Merge branch 'for-next/ratp'

39 files changed, 8468 insertions, 3 deletions

diff --git a/.gitignore b/.gitignore
index ce2be8ac04..bbcfa22447 100644
--- a/.gitignore
+++ b/.gitignore
@@ -23,6 +23,7 @@
 *.symtypes
 *.elf
 *.patch
+*.pyc
 *.mcp
 *.bct
 *.dcd
diff --git a/Documentation/user/remote-control.rst b/Documentation/user/remote-control.rst
new file mode 100644
index 0000000000..b9275cea80
--- /dev/null
+++ b/Documentation/user/remote-control.rst
@@ -0,0 +1,134 @@
+barebox remote control
+======================
+
+barebox remote control is for controlling barebox from a remote host via
+scripts. The barebox console is designed for human interaction,
+controlling it from a script is very error prone since UARTs do not
+offer reliable communication. Usually a tool like 'expect' is used for
+this purpose which uses its own language to communicate with the remote
+partner. The barebox remote control offers an alternative. barebox
+commands can be integrated into regular shell scripts running on the
+host:
+
+.. code-block:: sh
+
+  bbremote --port /dev/ttyUSB0 run "ls"
+
+Additionally files can be transferred from/to barebox and a regular
+console offers interactive access to barebox on flawy serial
+connections.
+
+Enabling remote control support
+-------------------------------
+
+To get remote control support barebox has to be compiled with
+CONFIG_RATP and CONFIG_CONSOLE_RATP enabled. Optionally CONFIG_FS_RATP
+can also be enabled.
+
+Running the bbremote tool
+-------------------------
+
+The bbremote host tool is written in python. To run it python2 has to be
+installed with the following additional packages:
+
++----------------+---------------------+
+| python package | Debian package name |
++================+=====================+
+| crcmod         | python-crcmod       |
++----------------+---------------------+
+| enum           | python-enum         |
++----------------+---------------------+
+| enum34         | python-enum34       |
++----------------+---------------------+
+
+If your distribution does not provide aforementioned packages, you can
+use 'pip' in order to install the dependencies localy to your user
+account via:
+
+.. code-block:: sh
+
+  pip install --user crcmod enum enum34
+
+configuring bbremote
+^^^^^^^^^^^^^^^^^^^^
+
+bbremote needs the port and possibly the baudrate to access the remote
+barebox. The port can be configured with the ``--baudrate`` option or
+with the ``BBREMOTE_PORT`` environment variable. The port can either be
+the device special file if it's a local port or if it's a remote port a
+string of the form: ``rfc2217://host:port``. The baudrate can be given
+with the ``--baudrate`` option or the ``BBREMOTE_BAUDRATE`` environment
+variable. For the rest of this document it is assumed that ``bbremote``
+has been configured using environment variables.
+
+running commands on the target
+------------------------------
+
+``bbremote`` can be used to run arbitrary commands on the remote
+barebox:
+
+.. code-block:: sh
+
+  bbremote run "echo huhu"
+  huhu
+
+The bbremote exit status will be 0 if the remote command exited
+successfully, 1 if the remote command failed and 127 if there was a
+communication error.
+
+**NOTE** It is possible to put the output into a shell variable for
+further processing, like ``RESULT=$(bbremote run "echo huhu")``.
+However, this string may contain unexpected messages from drivers and
+the like because currently we cannot filter out driver messages and
+messages to stderr.
+
+ping
+----
+
+This is a simple ping test.
+
+.. code-block:: sh
+
+  bbremote ping
+  pong
+
+getenv
+------
+
+.. code-block:: sh
+
+  bbremote getenv global.version
+  2015.12.0-00150-g81cd49f
+
+interactive console
+-------------------
+
+The bbremote tool also offers a regular interactive console to barebox.
+This is especially useful for flawy serial connections.
+
+.. code-block:: sh
+
+  bbremote console
+  barebox@Phytec phyFLEX-i.MX6 Quad Carrier-Board:/ ls
+  .      ..     dev    env    mnt
+
+*NOTE** To terminate resulting Barebox console session press 'Ctrl-T'
+
+**NOTE** You can also send 'ping' request to the target without
+ closing console session by pressint 'Ctrl-P'
+
+transferring files
+------------------
+
+With the bbremote tool it's possible to transfer files both from the
+host to barebox and from barebox to the host. Using the ``--export``
+option to bbremote a directory can be specified to export to barebox.
+This can be mounted on barebox using the regular mount command using
+``-t ratpfs`` as filesystem type.
+
+.. code-block:: sh
+
+  bbremote --export=somedir console
+  mkdir -p /ratpfs; mount -t ratpfs none /ratpfs
+  ls /ratpfs
+
diff --git a/common/Kconfig b/common/Kconfig
index 345de505c0..fc3ed8e57d 100644
--- a/common/Kconfig
+++ b/common/Kconfig
@@ -620,6 +620,16 @@ config PBL_CONSOLE
 	  must be running at the address it's linked at and bss must
 	  be cleared. On ARM that would be after setup_c().
 
+config CONSOLE_RATP
+	bool
+	select RATP
+	prompt "RATP console support"
+	help
+	  This option adds support for remote controlling barebox via serial
+	  port. The regular console is designed for human interaction whereas
+	  this option adds a machine readable interface for controlling barebox.
+	  Say yes here if you want to control barebox from a remote host.
+
 config PARTITION
 	bool
 	prompt "Enable Partitions"
diff --git a/common/Makefile b/common/Makefile
index ffaf8e7b42..d99ca7b7ac 100644
--- a/common/Makefile
+++ b/common/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_RESET_SOURCE)	+= reset_source.o
 obj-$(CONFIG_SHELL_HUSH)	+= hush.o
 obj-$(CONFIG_SHELL_SIMPLE)	+= parser.o
 obj-$(CONFIG_STATE)		+= state.o
+obj-$(CONFIG_RATP)		+= ratp.o
 obj-$(CONFIG_UIMAGE)		+= image.o uimage.o
 obj-$(CONFIG_FITIMAGE)		+= image-fit.o
 obj-$(CONFIG_MENUTREE)		+= menutree.o
@@ -55,6 +56,7 @@ obj-$(CONFIG_IMD)		+= imd.o
 obj-$(CONFIG_FILE_LIST)		+= file-list.o
 obj-$(CONFIG_FIRMWARE)		+= firmware.o
 obj-$(CONFIG_BAREBOX_UPDATE_IMX_NAND_FCB) += imx-bbu-nand-fcb.o
+obj-$(CONFIG_CONSOLE_RATP)	+= ratp.o
 
 quiet_cmd_pwd_h = PWDH    $@
 ifdef CONFIG_PASSWORD
diff --git a/common/console.c b/common/console.c
index 4a1d2576d0..a541892583 100644
--- a/common/console.c
+++ b/common/console.c
@@ -31,6 +31,7 @@
 #include <kfifo.h>
 #include <module.h>
 #include <poller.h>
+#include <ratp_bb.h>
 #include <magicvar.h>
 #include <globalvar.h>
 #include <linux/list.h>
@@ -313,8 +314,16 @@ static int getc_raw(void)
 			if (!(cdev->f_active & CONSOLE_STDIN))
 				continue;
 			active = 1;
-			if (cdev->tstc(cdev))
-				return cdev->getc(cdev);
+			if (cdev->tstc(cdev)) {
+				int ch = cdev->getc(cdev);
+
+				if (IS_ENABLED(CONFIG_RATP) && ch == 0x01) {
+					barebox_ratp(cdev);
+					return -1;
+				}
+
+				return ch;
+			}
 		}
 		if (!active)
 			/* no active console found. bail out */
@@ -349,16 +358,26 @@ int getc(void)
 	start = get_time_ns();
 	while (1) {
 		if (tstc_raw()) {
-			kfifo_putc(console_input_fifo, getc_raw());
+			int c = getc_raw();
+
+			if (c < 0)
+				break;
+
+			kfifo_putc(console_input_fifo, c);
 
 			start = get_time_ns();
 		}
+
 		if (is_timeout(start, 100 * USECOND) &&
 				kfifo_len(console_input_fifo))
 			break;
 	}
 
+	if (!kfifo_len(console_input_fifo))
+		return -1;
+
 	kfifo_getc(console_input_fifo, &ch);
+
 	return ch;
 }
 EXPORT_SYMBOL(getc);
diff --git a/common/ratp.c b/common/ratp.c
new file mode 100644
index 0000000000..2fef3cc0fe
--- /dev/null
+++ b/common/ratp.c
@@ -0,0 +1,511 @@
+/*
+ * Copyright (c) 2015 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ *
+ * See file CREDITS for list of people who contributed to this
+ * project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "barebox-ratp: " fmt
+
+#include <common.h>
+#include <command.h>
+#include <kfifo.h>
+#include <malloc.h>
+#include <init.h>
+#include <ratp.h>
+#include <command.h>
+#include <byteorder.h>
+#include <environment.h>
+#include <kfifo.h>
+#include <poller.h>
+#include <linux/sizes.h>
+#include <ratp_bb.h>
+#include <fs.h>
+
+#define BB_RATP_TYPE_COMMAND		1
+#define BB_RATP_TYPE_COMMAND_RETURN	2
+#define BB_RATP_TYPE_CONSOLEMSG		3
+#define BB_RATP_TYPE_PING		4
+#define BB_RATP_TYPE_PONG		5
+#define BB_RATP_TYPE_GETENV		6
+#define BB_RATP_TYPE_GETENV_RETURN	7
+#define BB_RATP_TYPE_FS			8
+#define BB_RATP_TYPE_FS_RETURN		9
+
+struct ratp_bb {
+	uint16_t type;
+	uint16_t flags;
+	uint8_t data[];
+};
+
+struct ratp_bb_command_return {
+	uint32_t errno;
+};
+
+struct ratp_ctx {
+	struct console_device *cdev;
+	struct ratp ratp;
+	int ratp_status;
+	struct console_device ratp_console;
+	int have_synch;
+	int in_ratp_console;
+
+	u8 sendbuf[256];
+	u8 sendbuf_len;
+
+	int old_active;
+
+	struct kfifo *console_recv_fifo;
+	struct kfifo *console_transmit_fifo;
+
+	struct ratp_bb_pkt *fs_rx;
+
+	struct poller_struct poller;
+};
+
+static int console_recv(struct ratp *r, uint8_t *data)
+{
+	struct ratp_ctx *ctx = container_of(r, struct ratp_ctx, ratp);
+	struct console_device *cdev = ctx->cdev;
+
+	if (ctx->have_synch) {
+		ctx->have_synch = 0;
+		*data = 0x01;
+		return 0;
+	}
+
+	if (!cdev->tstc(cdev))
+		return -EAGAIN;
+
+	*data = cdev->getc(cdev);
+
+	return 0;
+}
+
+static int console_send(struct ratp *r, void *pkt, int len)
+{
+	struct ratp_ctx *ctx = container_of(r, struct ratp_ctx, ratp);
+	struct console_device *cdev = ctx->cdev;
+	const uint8_t *buf = pkt;
+	int i;
+
+	for (i = 0; i < len; i++)
+		cdev->putc(cdev, buf[i]);
+
+	return 0;
+}
+
+static void *xmemdup_add_zero(const void *buf, int len)
+{
+	void *ret;
+
+	ret = xzalloc(len + 1);
+	*(uint8_t *)(ret + len) = 0;
+	memcpy(ret, buf, len);
+
+	return ret;
+}
+
+static void ratp_queue_console_tx(struct ratp_ctx *ctx)
+{
+	u8 buf[255];
+	struct ratp_bb *rbb = (void *)buf;
+	unsigned int now, maxlen = 255 - sizeof(*rbb);
+	int ret;
+
+	rbb->type = cpu_to_be16(BB_RATP_TYPE_CONSOLEMSG);
+
+	while (1) {
+		now = min(maxlen, kfifo_len(ctx->console_transmit_fifo));
+		if (!now)
+			break;
+
+		kfifo_get(ctx->console_transmit_fifo, rbb->data, now);
+
+		ret = ratp_send(&ctx->ratp, rbb, now + sizeof(*rbb));
+		if (ret)
+			return;
+	}
+}
+
+static int ratp_bb_send_command_return(struct ratp_ctx *ctx, uint32_t errno)
+{
+	void *buf;
+	struct ratp_bb *rbb;
+	struct ratp_bb_command_return *rbb_ret;
+	int len = sizeof(*rbb) + sizeof(*rbb_ret);
+	int ret;
+
+	ratp_queue_console_tx(ctx);
+
+	buf = xzalloc(len);
+	rbb = buf;
+	rbb_ret = buf + sizeof(*rbb);
+
+	rbb->type = cpu_to_be16(BB_RATP_TYPE_COMMAND_RETURN);
+	rbb_ret->errno = cpu_to_be32(errno);
+
+	ret = ratp_send(&ctx->ratp, buf, len);
+
+	free(buf);
+
+	return ret;
+}
+
+static int ratp_bb_send_pong(struct ratp_ctx *ctx)
+{
+	void *buf;
+	struct ratp_bb *rbb;
+	int len = sizeof(*rbb);
+	int ret;
+
+	buf = xzalloc(len);
+	rbb = buf;
+
+	rbb->type = cpu_to_be16(BB_RATP_TYPE_PONG);
+
+	ret = ratp_send(&ctx->ratp, buf, len);
+
+	free(buf);
+
+	return ret;
+}
+
+static int ratp_bb_send_getenv_return(struct ratp_ctx *ctx, const char *val)
+{
+	void *buf;
+	struct ratp_bb *rbb;
+	int len, ret;
+
+	if (!val)
+	    val = "";
+
+	len = sizeof(*rbb) + strlen(val);
+	buf = xzalloc(len);
+	rbb = buf;
+	strcpy(rbb->data, val);
+
+	rbb->type = cpu_to_be16(BB_RATP_TYPE_GETENV_RETURN);
+
+	ret = ratp_send(&ctx->ratp, buf, len);
+
+	free(buf);
+
+	return ret;
+}
+
+static char *ratp_command;
+static struct ratp_ctx *ratp_command_ctx;
+
+static int ratp_bb_dispatch(struct ratp_ctx *ctx, const void *buf, int len)
+{
+	const struct ratp_bb *rbb = buf;
+	struct ratp_bb_pkt *pkt;
+	int dlen = len - sizeof(struct ratp_bb);
+	char *varname;
+	int ret = 0;
+
+	switch (be16_to_cpu(rbb->type)) {
+	case BB_RATP_TYPE_COMMAND:
+		if (ratp_command)
+			return 0;
+
+		ratp_command = xmemdup_add_zero(&rbb->data, dlen);
+		ratp_command_ctx = ctx;
+		pr_debug("got command: %s\n", ratp_command);
+
+		break;
+
+	case BB_RATP_TYPE_COMMAND_RETURN:
+	case BB_RATP_TYPE_PONG:
+		break;
+
+	case BB_RATP_TYPE_CONSOLEMSG:
+
+		kfifo_put(ctx->console_recv_fifo, rbb->data, dlen);
+		break;
+
+	case BB_RATP_TYPE_PING:
+		ret = ratp_bb_send_pong(ctx);
+		break;
+
+	case BB_RATP_TYPE_GETENV:
+		varname = xmemdup_add_zero(&rbb->data, dlen);
+
+		ret = ratp_bb_send_getenv_return(ctx, getenv(varname));
+		break;
+
+	case BB_RATP_TYPE_FS_RETURN:
+		pkt = xzalloc(sizeof(*pkt) + dlen);
+		pkt->len = dlen;
+		memcpy(pkt->data, &rbb->data, dlen);
+		ctx->fs_rx = pkt;
+		break;
+	default:
+		printf("%s: unhandled packet type 0x%04x\n", __func__, be16_to_cpu(rbb->type));
+		break;
+	}
+
+	return ret;
+}
+
+static int ratp_console_getc(struct console_device *cdev)
+{
+	struct ratp_ctx *ctx = container_of(cdev, struct ratp_ctx, ratp_console);
+	unsigned char c;
+
+	if (!kfifo_len(ctx->console_recv_fifo))
+		return -1;
+
+	kfifo_getc(ctx->console_recv_fifo, &c);
+
+	return c;
+}
+
+static int ratp_console_tstc(struct console_device *cdev)
+{
+	struct ratp_ctx *ctx = container_of(cdev, struct ratp_ctx, ratp_console);
+
+	return kfifo_len(ctx->console_recv_fifo) ? 1 : 0;
+}
+
+static int ratp_console_puts(struct console_device *cdev, const char *s)
+{
+	struct ratp_ctx *ctx = container_of(cdev, struct ratp_ctx, ratp_console);
+	int len = 0;
+
+	len = strlen(s);
+
+	if (ratp_busy(&ctx->ratp))
+		return len;
+
+	kfifo_put(ctx->console_transmit_fifo, s, len);
+
+	return len;
+}
+
+static void ratp_console_putc(struct console_device *cdev, char c)
+{
+	struct ratp_ctx *ctx = container_of(cdev, struct ratp_ctx, ratp_console);
+
+	if (ratp_busy(&ctx->ratp))
+		return;
+
+	kfifo_putc(ctx->console_transmit_fifo, c);
+}
+
+static int ratp_console_register(struct ratp_ctx *ctx)
+{
+	int ret;
+
+	ctx->ratp_console.tstc = ratp_console_tstc;
+	ctx->ratp_console.puts = ratp_console_puts;
+	ctx->ratp_console.putc = ratp_console_putc;
+	ctx->ratp_console.getc = ratp_console_getc;
+	ctx->ratp_console.devname = "ratpconsole";
+	ctx->ratp_console.devid = DEVICE_ID_SINGLE;
+
+	ret = console_register(&ctx->ratp_console);
+	if (ret) {
+		pr_err("registering failed with %s\n", strerror(-ret));
+		return ret;
+	}
+
+	return 0;
+}
+
+void ratp_run_command(void)
+{
+	int ret;
+
+	if (!ratp_command)
+		return;
+
+	pr_debug("running command: %s\n", ratp_command);
+
+	ret = run_command(ratp_command);
+
+	free(ratp_command);
+	ratp_command = NULL;
+
+	ratp_bb_send_command_return(ratp_command_ctx, ret);
+}
+
+static const char *ratpfs_mount_path;
+
+int barebox_ratp_fs_mount(const char *path)
+{
+	if (path && ratpfs_mount_path)
+		return -EBUSY;
+
+	ratpfs_mount_path = path;
+
+	return 0;
+}
+
+static void ratp_console_unregister(struct ratp_ctx *ctx)
+{
+	int ret;
+
+	console_set_active(&ctx->ratp_console, 0);
+	poller_unregister(&ctx->poller);
+	ratp_close(&ctx->ratp);
+	console_set_active(ctx->cdev, ctx->old_active);
+	ctx->cdev = NULL;
+
+	if (ratpfs_mount_path) {
+		ret = umount(ratpfs_mount_path);
+		if (!ret)
+			ratpfs_mount_path = NULL;
+	}
+}
+
+static void ratp_poller(struct poller_struct *poller)
+{
+	struct ratp_ctx *ctx = container_of(poller, struct ratp_ctx, poller);
+	int ret;
+	size_t len;
+	void *buf;
+
+	ratp_queue_console_tx(ctx);
+
+	ret = ratp_poll(&ctx->ratp);
+	if (ret == -EINTR)
+		goto out;
+	if (ratp_closed(&ctx->ratp))
+		goto out;
+
+	ret = ratp_recv(&ctx->ratp, &buf, &len);
+	if (ret < 0)
+		return;
+
+	ratp_bb_dispatch(ctx, buf, len);
+
+	free(buf);
+
+	return;
+
+out:
+	ratp_console_unregister(ctx);
+}
+
+static int do_ratp_close(int argc, char *argv[])
+{
+	if (ratp_command_ctx && ratp_command_ctx->cdev)
+		ratp_console_unregister(ratp_command_ctx);
+	else
+		printf("ratp is not active\n");
+
+	return 0;
+}
+
+BAREBOX_CMD_START(ratp_close)
+	.cmd	= do_ratp_close,
+};
+
+int barebox_ratp_fs_call(struct ratp_bb_pkt *tx, struct ratp_bb_pkt **rx)
+{
+	struct ratp_ctx *ctx = ratp_command_ctx;
+	struct ratp_bb *rbb;
+	int len;
+	u64 start;
+
+	if (!ctx)
+		return -EINVAL;
+
+	ctx->fs_rx = NULL;
+
+	len = sizeof(*rbb) + tx->len;
+	rbb = xzalloc(len);
+	rbb->type = cpu_to_be16(BB_RATP_TYPE_FS);
+	memcpy(rbb->data, tx->data, tx->len);
+
+	if (ratp_send(&ctx->ratp, rbb, len) != 0)
+		pr_debug("failed to send port pkt\n");
+
+	free(rbb);
+
+	start = get_time_ns();
+
+	while (!ctx->fs_rx) {
+		poller_call();
+		if (ratp_closed(&ctx->ratp))
+			return -EIO;
+		if (is_timeout(start, 10 * SECOND))
+			return -ETIMEDOUT;
+	}
+
+	*rx = ctx->fs_rx;
+
+	pr_debug("%s: len %i\n", __func__, ctx->fs_rx->len);
+
+	return 0;
+}
+
+int barebox_ratp(struct console_device *cdev)
+{
+	int ret;
+	struct ratp_ctx *ctx;
+	struct ratp *ratp;
+
+	if (ratp_command_ctx) {
+		ctx = ratp_command_ctx;
+	} else {
+		ctx = xzalloc(sizeof(*ctx));
+		ratp_command_ctx = ctx;
+		ctx->ratp.send = console_send;
+		ctx->ratp.recv = console_recv;
+		ctx->console_recv_fifo = kfifo_alloc(512);
+		ctx->console_transmit_fifo = kfifo_alloc(SZ_128K);
+		ctx->poller.func = ratp_poller;
+		ratp_console_register(ctx);
+	}
+
+	if (ctx->cdev)
+		return -EBUSY;
+
+	ratp = &ctx->ratp;
+
+	ctx->old_active = console_get_active(cdev);
+	console_set_active(cdev, 0);
+
+	ctx->cdev = cdev;
+	ctx->have_synch = 1;
+
+	ret = ratp_establish(ratp, false, 100);
+	if (ret < 0)
+		goto out;
+
+	ret = poller_register(&ctx->poller);
+	if (ret)
+		goto out1;
+
+	console_set_active(&ctx->ratp_console, CONSOLE_STDOUT | CONSOLE_STDERR |
+			CONSOLE_STDIN);
+
+	return 0;
+
+out1:
+	ratp_close(ratp);
+out:
+	console_set_active(ctx->cdev, ctx->old_active);
+	ctx->cdev = NULL;
+
+	return ret;
+}
+
+static void barebox_ratp_close(void)
+{
+	if (ratp_command_ctx && ratp_command_ctx->cdev)
+		ratp_console_unregister(ratp_command_ctx);
+}
+predevshutdown_exitcall(barebox_ratp_close);
\ No newline at end of file
diff --git a/crypto/Kconfig b/crypto/Kconfig
index ca6f03a1ed..9b347f872f 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -4,6 +4,7 @@ config CRC32
 	bool
 
 config CRC16
+	default y
 	bool
 
 config CRC7
diff --git a/defaultenv/defaultenv-2-base/init/automount-ratp b/defaultenv/defaultenv-2-base/init/automount-ratp
new file mode 100644
index 0000000000..6474df8348
--- /dev/null
+++ b/defaultenv/defaultenv-2-base/init/automount-ratp
@@ -0,0 +1,6 @@
+#!/bin/sh
+
+# automount ratp filesystem
+
+mkdir -p /mnt/ratp
+automount /mnt/ratp 'mount -t ratpfs none /mnt/ratp'
\ No newline at end of file
diff --git a/fs/Kconfig b/fs/Kconfig
index 5413a9295c..56fe41a284 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -91,4 +91,12 @@ config FS_SMHFS
 
 source fs/pstore/Kconfig
 
+config FS_RATP
+	bool
+	depends on CONSOLE_RATP
+	prompt "RATP filesystem support"
+	help
+	  This enables support for transferring files over RATP. A host can
+	  export a directory which can then be mounted under barebox.
+
 endmenu
diff --git a/fs/Makefile b/fs/Makefile
index 2f952038d1..7896e385a0 100644
--- a/fs/Makefile
+++ b/fs/Makefile
@@ -15,3 +15,4 @@ obj-$(CONFIG_FS_EFI)	 += efi.o
 obj-$(CONFIG_FS_EFIVARFS) += efivarfs.o
 obj-$(CONFIG_FS_SMHFS) += smhfs.o
 obj-$(CONFIG_FS_PSTORE) += pstore/
+obj-$(CONFIG_FS_RATP)	+= ratpfs.o
diff --git a/fs/ratpfs.c b/fs/ratpfs.c
new file mode 100644
index 0000000000..902289bab1
--- /dev/null
+++ b/fs/ratpfs.c
@@ -0,0 +1,476 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; version 2.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ */
+
+#define pr_fmt(fmt) "barebox-ratpfs: " fmt
+
+#include <common.h>
+#include <command.h>
+#include <init.h>
+#include <malloc.h>
+#include <fs.h>
+#include <errno.h>
+#include <linux/stat.h>
+#include <asm/unaligned.h>
+#include <ratp_bb.h>
+
+#define RATPFS_TYPE_MOUNT_CALL       1
+#define RATPFS_TYPE_MOUNT_RETURN     2
+#define RATPFS_TYPE_READDIR_CALL     3
+#define RATPFS_TYPE_READDIR_RETURN   4
+#define RATPFS_TYPE_STAT_CALL        5
+#define RATPFS_TYPE_STAT_RETURN      6
+#define RATPFS_TYPE_OPEN_CALL        7
+#define RATPFS_TYPE_OPEN_RETURN      8
+#define RATPFS_TYPE_READ_CALL        9
+#define RATPFS_TYPE_READ_RETURN     10
+#define RATPFS_TYPE_WRITE_CALL      11
+#define RATPFS_TYPE_WRITE_RETURN    12
+#define RATPFS_TYPE_CLOSE_CALL      13
+#define RATPFS_TYPE_CLOSE_RETURN    14
+#define RATPFS_TYPE_TRUNCATE_CALL   15
+#define RATPFS_TYPE_TRUNCATE_RETURN 16
+
+struct ratpfs_file {
+	uint32_t handle;
+};
+
+struct ratpfs_dir {
+	char *entries;
+	int len, off;
+	DIR dir;
+};
+
+static int ratpfs_create(struct device_d __always_unused *dev,
+			const char __always_unused *pathname,
+			mode_t __always_unused mode)
+{
+	pr_debug("%s\n", __func__);
+
+	return 0;
+}
+
+static int ratpfs_mkdir(struct device_d __always_unused *dev,
+		       const char __always_unused *pathname)
+{
+	pr_debug("%s\n", __func__);
+
+	return -ENOSYS;
+}
+
+static int ratpfs_rm(struct device_d __always_unused *dev,
+		    const char *pathname)
+{
+	pr_debug("%s\n", __func__);
+
+	/* Get rid of leading '/' */
+	pathname = &pathname[1];
+
+	return 0;
+}
+
+static int ratpfs_truncate(struct device_d __always_unused *dev,
+			  FILE *f, ulong size)
+{
+	int len_tx = 1 /* type */
+		+ 4 /* handle */
+		+ 4 /* size */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx)+len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_file *rfile = f->priv;
+	int ret;
+
+	pr_debug("%s: len_tx=%i handle=%i size=%i\n", __func__,
+		 len_tx, rfile->handle, (int)size);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_TRUNCATE_CALL;
+	put_unaligned_be32(rfile->handle, &pkt_tx->data[1]);
+	put_unaligned_be32(size, &pkt_tx->data[5]);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_TRUNCATE_RETURN) {
+		pr_err("invalid truncate response\n");
+		ret = -EIO;
+		goto out;
+	}
+
+out:
+	free(pkt_rx);
+	return ret;
+}
+
+static int ratpfs_open(struct device_d __always_unused *dev,
+		      FILE *file, const char *filename)
+{
+	int len_name = strlen(filename);
+	int len_tx = 1 /* type */
+		+ 4 /* flags */
+		+ len_name /* path */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_file *rfile = xzalloc(sizeof(*rfile));
+	int ret;
+
+	pr_debug("%s: len_tx=%i filename='%s'\n", __func__, len_tx, filename);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_OPEN_CALL;
+	put_unaligned_be32(file->flags, &pkt_tx->data[1]);
+	memcpy(&pkt_tx->data[5], filename, len_name);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto err;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_OPEN_RETURN) {
+		pr_err("invalid open response\n");
+		ret = -EIO;
+		goto err;
+	}
+	rfile->handle = get_unaligned_be32(&pkt_rx->data[1]);
+	if (rfile->handle == 0) {
+		ret = -get_unaligned_be32(&pkt_rx->data[5]); /* errno */
+		goto err;
+	}
+	file->priv = rfile;
+	file->size = get_unaligned_be32(&pkt_rx->data[5]);
+
+	goto out;
+
+err:
+	file->priv = NULL;
+	free(rfile);
+out:
+	free(pkt_rx);
+	return ret;
+}
+
+static int ratpfs_close(struct device_d __always_unused *dev,
+			FILE *f)
+{
+	int len_tx = 1 /* type */
+		+ 4 /* handle */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_file *rfile = f->priv;
+	int ret;
+
+	pr_debug("%s: len_tx=%i handle=%i\n", __func__,
+		 len_tx, rfile->handle);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_CLOSE_CALL;
+	put_unaligned_be32(rfile->handle, &pkt_tx->data[1]);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_CLOSE_RETURN) {
+		pr_err("invalid close response\n");
+		goto out;
+	}
+
+out:
+	free(pkt_rx);
+	return ret;
+}
+
+static int ratpfs_write(struct device_d __always_unused *dev,
+			FILE *f, const void *buf, size_t orig_size)
+{
+	int size = min((int)orig_size, 4096);
+	int len_tx = 1 /* type */
+		+ 4 /* handle */
+		+ 4 /* pos */
+		+ size /* data */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_file *rfile = f->priv;
+	int ret;
+
+	pr_debug("%s: len_tx=%i handle=%i pos=%i size=%i\n", __func__,
+		 len_tx, rfile->handle, (int)f->pos, size);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_WRITE_CALL;
+	put_unaligned_be32(rfile->handle, &pkt_tx->data[1]);
+	put_unaligned_be32(f->pos, &pkt_tx->data[5]);
+	memcpy(&pkt_tx->data[9], buf, size);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_WRITE_RETURN) {
+		pr_err("invalid write response\n");
+		ret = -EIO;
+		goto out;
+	}
+
+	ret = size;
+out:
+	free(pkt_rx);
+
+	return ret;
+}
+
+static int ratpfs_read(struct device_d __always_unused *dev,
+		       FILE *f, void *buf, size_t orig_size)
+{
+	int size = min((int)orig_size, 4096);
+	int len_tx = 1 /* type */
+		+ 4 /* handle */
+		+ 4 /* pos */
+		+ 4 /* size */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_file *rfile = f->priv;
+	int ret;
+
+	pr_debug("%s: len_tx=%i handle=%i pos=%i size=%i\n", __func__,
+		 len_tx, rfile->handle, (int)f->pos, size);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_READ_CALL;
+	put_unaligned_be32(rfile->handle, &pkt_tx->data[1]);
+	put_unaligned_be32(f->pos, &pkt_tx->data[5]);
+	put_unaligned_be32(size, &pkt_tx->data[9]);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_READ_RETURN) {
+		pr_err("invalid read response\n");
+		ret = -EIO;
+		goto out;
+	}
+	size = pkt_rx->len - 1;
+	memcpy(buf, &pkt_rx->data[1], size);
+	ret = size;
+
+out:
+	free(pkt_rx);
+	return ret;
+}
+
+static loff_t ratpfs_lseek(struct device_d __always_unused *dev,
+			  FILE *f, loff_t pos)
+{
+	pr_debug("%s\n", __func__);
+	f->pos = pos;
+	return f->pos;
+}
+
+static DIR* ratpfs_opendir(struct device_d __always_unused *dev,
+			  const char *pathname)
+{
+	int len_name = strlen(pathname);
+	int len_tx = 1 /* type */
+		+ len_name /* path */;
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx)+len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	struct ratpfs_dir *rdir = xzalloc(sizeof(*rdir));
+	int ret;
+
+	pr_debug("%s: len_tx=%i pathname='%s'\n", __func__, len_tx, pathname);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_READDIR_CALL;
+	memcpy(&pkt_tx->data[1], pathname, len_name);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (!ret) {
+		pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+		if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_READDIR_RETURN) {
+			pr_err("invalid readdir response\n");
+			free(pkt_rx);
+			return NULL;
+		}
+		rdir->len = pkt_rx->len - 1;
+		rdir->entries = xmemdup(&pkt_rx->data[1], rdir->len);
+		free(pkt_rx);
+		return &rdir->dir;
+	} else {
+		return NULL;
+	}
+}
+
+static struct dirent *ratpfs_readdir(struct device_d *dev, DIR *dir)
+{
+	struct ratpfs_dir *rdir = container_of(dir, struct ratpfs_dir, dir);
+	int i;
+
+	pr_debug("%s\n", __func__);
+
+	if (rdir->len <= rdir->off)
+		return NULL;
+
+	for (i = 0; rdir->off < rdir->len; rdir->off++, i++) {
+		dir->d.d_name[i] = rdir->entries[rdir->off];
+		if (dir->d.d_name[i] == 0)
+			break;
+	}
+	rdir->off++;
+
+	return &dir->d;
+}
+
+static int ratpfs_closedir(struct device_d *dev, DIR *dir)
+{
+	struct ratpfs_dir *rdir = container_of(dir, struct ratpfs_dir, dir);
+
+	pr_debug("%s\n", __func__);
+
+	free(rdir->entries);
+	free(rdir);
+
+	return 0;
+}
+
+static int ratpfs_stat(struct device_d __always_unused *dev,
+		      const char *filename, struct stat *s)
+{
+	int len_name = strlen(filename);
+	int len_tx = 1 /* type */
+		+ len_name; /* path */
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	int ret;
+
+	pr_debug("%s: len_tx=%i filename='%s'\n", __func__, len_tx, filename);
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_STAT_CALL;
+	memcpy(&pkt_tx->data[1], filename, len_name);
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret) {
+		ret = -EIO;
+		goto out;
+	}
+
+	pr_debug("%s: len_rx=%i\n", __func__, pkt_rx->len);
+	if (pkt_rx->len < 6 || pkt_rx->data[0] != RATPFS_TYPE_STAT_RETURN) {
+		pr_err("invalid stat response\n");
+		goto out;
+	}
+	switch (pkt_rx->data[1]) {
+	case 0:
+		ret = -ENOENT;
+		break;
+	case 1:
+		s->st_mode = S_IFREG | S_IRWXU | S_IRWXG | S_IRWXO;
+		break;
+	case 2:
+		s->st_mode = S_IFDIR | S_IRWXU | S_IRWXG | S_IRWXO;
+		break;
+	}
+	s->st_size = get_unaligned_be32(&pkt_rx->data[2]);
+
+out:
+	free(pkt_rx);
+	return ret;
+}
+
+static int ratpfs_probe(struct device_d *dev)
+{
+	int len_tx = 1; /* type */
+	struct ratp_bb_pkt *pkt_tx = xzalloc(sizeof(*pkt_tx) + len_tx);
+	struct ratp_bb_pkt *pkt_rx = NULL;
+	int ret;
+	struct fs_device_d *fsdev = dev_to_fs_device(dev);
+
+	pr_debug("%s\n", __func__);
+
+	ret = barebox_ratp_fs_mount(fsdev->path);
+	if (ret)
+		return ret;
+
+	pkt_tx->len = len_tx;
+	pkt_tx->data[0] = RATPFS_TYPE_MOUNT_CALL;
+
+	ret = barebox_ratp_fs_call(pkt_tx, &pkt_rx);
+	if (ret)
+		goto out;
+
+	if (pkt_rx->len < 1 || pkt_rx->data[0] != RATPFS_TYPE_MOUNT_RETURN) {
+		pr_err("invalid mount response\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+out:
+	free(pkt_rx);
+
+	if (ret)
+		barebox_ratp_fs_mount(NULL);
+
+	return ret;
+}
+
+static void ratpfs_remove(struct device_d __always_unused *dev)
+{
+	pr_debug("%s\n", __func__);
+
+	barebox_ratp_fs_mount(NULL);
+}
+
+static struct fs_driver_d ratpfs_driver = {
+	.open      = ratpfs_open,
+	.close     = ratpfs_close,
+	.read      = ratpfs_read,
+	.lseek     = ratpfs_lseek,
+	.opendir   = ratpfs_opendir,
+	.readdir   = ratpfs_readdir,
+	.closedir  = ratpfs_closedir,
+	.stat      = ratpfs_stat,
+	.create    = ratpfs_create,
+	.unlink    = ratpfs_rm,
+	.mkdir     = ratpfs_mkdir,
+	.rmdir     = ratpfs_rm,
+	.write     = ratpfs_write,
+	.truncate  = ratpfs_truncate,
+	.flags     = FS_DRIVER_NO_DEV,
+	.drv = {
+		.probe  = ratpfs_probe,
+		.remove = ratpfs_remove,
+		.name = "ratpfs",
+	}
+};
+
+static int ratpfs_init(void)
+{
+	return register_fs_driver(&ratpfs_driver);
+}
+coredevice_initcall(ratpfs_init);
\ No newline at end of file
diff --git a/include/ratp.h b/include/ratp.h
new file mode 100644
index 0000000000..94fd004f45
--- /dev/null
+++ b/include/ratp.h
@@ -0,0 +1,22 @@
+#ifndef __RATP_H
+#define __RATP_H
+
+struct ratp {
+	struct ratp_internal *internal;
+	int (*send)(struct ratp *, void *pkt, int len);
+	int (*recv)(struct ratp *, uint8_t *data);
+};
+
+int ratp_establish(struct ratp *ratp, bool active, int timeout_ms);
+void ratp_close(struct ratp *ratp);
+int ratp_recv(struct ratp *ratp, void **data, size_t *len);
+int ratp_send(struct ratp *ratp, const void *data, size_t len);
+int ratp_send_complete(struct ratp *ratp, const void *data, size_t len,
+		   void (*complete)(void *ctx, int status), void *complete_ctx);
+int ratp_poll(struct ratp *ratp);
+bool ratp_closed(struct ratp *ratp);
+bool ratp_busy(struct ratp *ratp);
+
+void ratp_run_command(void);
+
+#endif /* __RATP_H */
\ No newline at end of file
diff --git a/include/ratp_bb.h b/include/ratp_bb.h
new file mode 100644
index 0000000000..52ecaff374
--- /dev/null
+++ b/include/ratp_bb.h
@@ -0,0 +1,15 @@
+#ifndef __RATP_BB_H
+#define __RATP_BB_H
+
+struct ratp_bb_pkt {
+	struct list_head list;
+
+	unsigned int len;
+	uint8_t data[];
+};
+
+int barebox_ratp(struct console_device *cdev);
+int barebox_ratp_fs_call(struct ratp_bb_pkt *tx, struct ratp_bb_pkt **rx);
+int barebox_ratp_fs_mount(const char *path);
+
+#endif /* __RATP_BB_H */
diff --git a/lib/Kconfig b/lib/Kconfig
index 46ec58c62e..f05175103c 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -58,6 +58,14 @@ config LIBMTD
 config STMP_DEVICE
 	bool
 
+config RATP
+	select CRC16
+	bool
+	help
+	  Reliable Asynchronous Transfer Protocol (RATP) is a protocol for reliably
+	  transferring packets over serial links described in RFC916. This implementation
+	  is used for controlling barebox over serial ports.
+
 source lib/gui/Kconfig
 
 source lib/fonts/Kconfig
diff --git a/lib/Makefile b/lib/Makefile
index 6ffa3e0104..44ba25b766 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -57,3 +57,4 @@ obj-y			+= hexdump.o
 obj-$(CONFIG_FONTS)	+= fonts/
 obj-$(CONFIG_BAREBOX_LOGO)     += logo/
 obj-y			+= reed_solomon/
+obj-$(CONFIG_RATP)	+= ratp.o
diff --git a/lib/ratp.c b/lib/ratp.c
new file mode 100644
index 0000000000..d596a0e8b2
--- /dev/null
+++ b/lib/ratp.c
@@ -0,0 +1,1834 @@
+/*
+ * barebox RATP implementation.
+ * This is the barebox implementation for the Reliable Asynchronous
+ * Transfer Protocol (RATP) as described in RFC916.
+ *
+ * Copyright (C) 2015 Pengutronix, Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#define pr_fmt(fmt)  "ratp: " fmt
+
+#include <common.h>
+#include <malloc.h>
+#include <getopt.h>
+#include <ratp.h>
+#include <crc.h>
+#include <clock.h>
+#include <asm/unaligned.h>
+
+/*
+ * RATP packet format:
+ *
+ * Byte No.
+ *
+ *        +-------------------------------+
+ *        |                               |
+ *    1   |          Synch Leader         | Hex 01
+ *        |                               |
+ *        +-------------------------------+
+ *        | S | A | F | R | S | A | E | S |
+ *    2   | Y | C | I | S | N | N | O | O | Control
+ *        | N | K | N | T |   |   | R |   |
+ *        +-------------------------------+
+ *        |                               |
+ *    3   |      Data length (0-255)      |
+ *        |                               |
+ *        +-------------------------------+
+ *        |                               |
+ *    4   |        Header Checksum        |
+ *        |                               |
+ *        +-------------------------------+
+ *
+ */
+
+struct ratp_header {
+	uint8_t	synch;
+	uint8_t	control;
+	uint8_t	data_length;
+	uint8_t	cksum;
+};
+
+#define RATP_CONTROL_SO		(1 << 0)
+#define RATP_CONTROL_EOR	(1 << 1)
+#define RATP_CONTROL_AN		(1 << 2)
+#define RATP_CONTROL_SN		(1 << 3)
+#define RATP_CONTROL_RST	(1 << 4)
+#define RATP_CONTROL_FIN	(1 << 5)
+#define RATP_CONTROL_ACK	(1 << 6)
+#define RATP_CONTROL_SYN	(1 << 7)
+
+enum ratp_state {
+	RATP_STATE_LISTEN,
+	RATP_STATE_SYN_SENT,
+	RATP_STATE_SYN_RECEIVED,
+	RATP_STATE_ESTABLISHED,
+	RATP_STATE_FIN_WAIT,
+	RATP_STATE_LAST_ACK,
+	RATP_STATE_CLOSING,
+	RATP_STATE_TIME_WAIT,
+	RATP_STATE_CLOSED,
+};
+
+struct ratp_message {
+	void *buf;
+	size_t len;
+	struct list_head list;
+	void (*complete)(void *ctx, int status);
+	void *complete_ctx;
+	int eor;
+};
+
+static char *ratp_state_str[] = {
+	[RATP_STATE_LISTEN]       = "LISTEN",
+	[RATP_STATE_SYN_SENT]     = "SYN_SENT",
+	[RATP_STATE_SYN_RECEIVED] = "SYN_RECEIVED",
+	[RATP_STATE_ESTABLISHED]  = "ESTABLISHED",
+	[RATP_STATE_FIN_WAIT]     = "FIN_WAIT",
+	[RATP_STATE_LAST_ACK]     = "LAST_ACK",
+	[RATP_STATE_CLOSING]      = "CLOSING",
+	[RATP_STATE_TIME_WAIT]    = "TIME_WAIT",
+	[RATP_STATE_CLOSED]       = "CLOSED",
+};
+
+struct ratp_internal {
+	struct ratp *ratp;
+
+	enum ratp_state state;
+	int sn_sent;
+	int sn_received;
+	int active;
+
+	void *recvbuf;
+	void *sendbuf;
+	int sendbuf_len;
+
+	struct list_head recvmsg;
+	struct list_head sendmsg;
+
+	struct ratp_message *sendmsg_current;
+
+	uint64_t timewait_timer_start;
+	uint64_t retransmission_timer_start;
+	int max_retransmission;
+	int retransmission_count;
+	int srtt;
+	int rto;
+
+	int status;
+
+	int in_ratp;
+};
+
+static bool ratp_sn(struct ratp_header *hdr)
+{
+	return hdr->control & RATP_CONTROL_SN ? 1 : 0;
+}
+
+static bool ratp_an(struct ratp_header *hdr)
+{
+	return hdr->control & RATP_CONTROL_AN ? 1 : 0;
+}
+
+#define ratp_set_sn(sn) (((sn) % 2) ? RATP_CONTROL_SN : 0)
+#define ratp_set_an(an) (((an) % 2) ? RATP_CONTROL_AN : 0)
+
+static inline int ratp_header_ok(struct ratp_internal *ri, struct ratp_header *h)
+{
+	uint8_t cksum;
+	int ret;
+
+	cksum = h->control;
+	cksum += h->data_length;
+	cksum += h->cksum;
+
+	ret = cksum == 0xff ? 1 : 0;
+
+	if (ret)
+		pr_vdebug("Header ok\n");
+	else
+		pr_vdebug("Header cksum failed: %02x\n", cksum);
+
+	return ret;
+}
+
+static bool ratp_has_data(struct ratp_header *hdr)
+{
+	if (hdr->control & RATP_CONTROL_SO)
+		return 1;
+	if (hdr->data_length)
+		return 1;
+	return 0;
+}
+
+static void ratp_print_header(struct ratp_internal *ri, struct ratp_header *hdr,
+		const char *prefix)
+{
+	uint8_t control = hdr->control;
+
+	pr_debug("%s>%s %s %s %s %s %s %s %s< len: %-3d\n",
+		prefix,
+		control & RATP_CONTROL_SO  ? "so" : "--",
+		control & RATP_CONTROL_EOR ? "eor" : "---",
+		control & RATP_CONTROL_AN ? "an" : "--",
+		control & RATP_CONTROL_SN ? "sn" : "--",
+		control & RATP_CONTROL_RST ? "rst" : "---",
+		control & RATP_CONTROL_FIN ? "fin" : "---",
+		control & RATP_CONTROL_ACK ? "ack" : "---",
+		control & RATP_CONTROL_SYN ? "syn" : "---",
+		hdr->data_length);
+
+#ifdef VERBOSE_DEBUG
+	if (hdr->data_length)
+		memory_display(hdr + 1, 0, hdr->data_length, 1, 0);
+#endif
+}
+
+static void ratp_create_packet(struct ratp_internal *ri, struct ratp_header *hdr,
+		uint8_t control, uint8_t length)
+{
+	hdr->synch = 0x1;
+	hdr->control = control;
+	hdr->data_length = length;
+	hdr->cksum = (control + length) ^ 0xff;
+}
+
+static void ratp_state_change(struct ratp_internal *ri, enum ratp_state state)
+{
+	pr_debug("state %-10s -> %-10s\n", ratp_state_str[ri->state],
+			ratp_state_str[state]);
+
+	ri->state = state;
+}
+
+#define RATP_CONTROL_SO		(1 << 0)
+#define RATP_CONTROL_EOR	(1 << 1)
+#define RATP_CONTROL_AN		(1 << 2)
+#define RATP_CONTROL_SN		(1 << 3)
+#define RATP_CONTROL_RST	(1 << 4)
+#define RATP_CONTROL_FIN	(1 << 5)
+#define RATP_CONTROL_ACK	(1 << 6)
+#define RATP_CONTROL_SYN	(1 << 7)
+
+static int ratp_send_pkt(struct ratp_internal *ri, void *pkt, int length)
+{
+	struct ratp_header *hdr = (void *)pkt;
+
+	ratp_print_header(ri, hdr, "send");
+
+	if (ratp_has_data(hdr) ||
+	    (hdr->control & (RATP_CONTROL_SYN | RATP_CONTROL_RST | RATP_CONTROL_FIN))) {
+		memcpy(ri->sendbuf, pkt, length);
+		ri->sn_sent = ratp_sn(hdr);
+		ri->sendbuf_len = length;
+		ri->retransmission_timer_start = get_time_ns();
+		ri->retransmission_count = 0;
+	}
+
+	return ri->ratp->send(ri->ratp, pkt, length);
+}
+
+static int ratp_send_hdr(struct ratp_internal *ri, uint8_t control)
+{
+	struct ratp_header hdr = {};
+
+	ratp_create_packet(ri, &hdr, control, 0);
+
+	return ratp_send_pkt(ri, &hdr, sizeof(hdr));
+}
+
+static int ratp_recv_char(struct ratp_internal *ri, uint8_t *data, int poll_timeout_ms)
+{
+	uint64_t start;
+	int ret;
+
+	start = get_time_ns();
+
+	while (1) {
+		ret = ri->ratp->recv(ri->ratp, data);
+		if (ret < 0 && ret != -EAGAIN)
+			return ret;
+
+		if (ret == 0)
+			return 0;
+
+		if (is_timeout(start, poll_timeout_ms * MSECOND))
+			return -EAGAIN;
+	}
+}
+
+static int ratp_recv_pkt_header(struct ratp_internal *ri, struct ratp_header *hdr,
+		int poll_timeout_ms)
+{
+	int ret;
+	uint8_t buf;
+
+	do {
+		ret = ratp_recv_char(ri, &buf, 0);
+		if (ret < 0)
+			return ret;
+		hdr->synch = buf;
+	} while (hdr->synch != 1);
+	ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
+	if (ret < 0)
+		return ret;
+
+	hdr->control = buf;
+	ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
+	if (ret < 0)
+		return ret;
+
+	hdr->data_length = buf;
+
+	ret = ratp_recv_char(ri, &buf, poll_timeout_ms);
+	if (ret < 0)
+		return ret;
+
+	hdr->cksum = buf;
+
+	if (!ratp_header_ok(ri, hdr))
+		return -EAGAIN;
+
+	return 0;
+}
+
+static int ratp_recv_pkt_data(struct ratp_internal *ri, void *data, uint8_t len,
+		int poll_timeout_ms)
+{
+	uint16_t crc_expect, crc_read;
+	int ret, i;
+
+	for (i = 0; i < len + 2; i++) {
+		ret = ratp_recv_char(ri, data + i, poll_timeout_ms);
+		if (ret < 0)
+			return ret;
+	}
+
+	crc_expect = cyg_crc16(data, len);
+
+	crc_read = get_unaligned_be16(data + len);
+
+	if (crc_expect != crc_read) {
+		pr_vdebug("Wrong CRC: expected: 0x%04x, got 0x%04x\n",
+				crc_expect, crc_read);
+		return -EBADMSG;
+	} else {
+		pr_vdebug("correct CRC: 0x%04x\n", crc_expect);
+	}
+
+	return 0;
+}
+
+static int ratp_recv_pkt(struct ratp_internal *ri, void *pkt, int poll_timeout_ms)
+{
+	struct ratp_header *hdr = pkt;
+	void *data = pkt + sizeof(struct ratp_header);
+	int ret;
+
+	ret = ratp_recv_pkt_header(ri, hdr, poll_timeout_ms);
+	if (ret < 0)
+		return ret;
+
+	if (hdr->control & (RATP_CONTROL_SO | RATP_CONTROL_RST | RATP_CONTROL_SYN |
+		RATP_CONTROL_FIN))
+		return 0;
+
+	if (hdr->data_length) {
+		ret = ratp_recv_pkt_data(ri, data, hdr->data_length,
+				poll_timeout_ms);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
+static bool ratp_an_expected(struct ratp_internal *ri, struct ratp_header *hdr)
+{
+	return ratp_an(hdr) == (ri->sn_sent + 1) % 2;
+}
+
+static bool ratp_sn_expected(struct ratp_internal *ri, struct ratp_header *hdr)
+{
+	return ratp_sn(hdr) != ri->sn_received;
+}
+
+static int ratp_send_ack(struct ratp_internal *ri, struct ratp_header *hdr)
+{
+	uint8_t control = RATP_CONTROL_ACK;
+	int ret;
+
+	if (hdr->control & RATP_CONTROL_SN)
+		control |= RATP_CONTROL_AN;
+	else
+		control |= 0;
+
+	ret = ratp_send_hdr(ri, control);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static int ratp_send_next_data(struct ratp_internal *ri)
+{
+	uint16_t crc;
+	uint8_t control = RATP_CONTROL_ACK;
+	struct ratp_header *hdr;
+	int pktlen;
+	struct ratp_message *msg;
+	int len;
+
+	if (ri->sendmsg_current) {
+		pr_err("%s: busy\n", __func__);
+		return -EBUSY;
+	}
+
+	if (list_empty(&ri->sendmsg))
+		return 0;
+
+	msg = list_first_entry(&ri->sendmsg, struct ratp_message, list);
+
+	ri->sendmsg_current = msg;
+
+	list_del(&msg->list);
+
+	len = msg->len;
+
+	control = ratp_set_sn(ri->sn_sent + 1) |
+		ratp_set_an(ri->sn_received + 1) |
+		RATP_CONTROL_ACK;
+
+	hdr = msg->buf;
+
+	if (msg->eor)
+		control |= RATP_CONTROL_EOR;
+
+	if (len > 1) {
+		void *data = hdr + 1;
+		pktlen = sizeof(*hdr) + len + 2;
+		crc = cyg_crc16(data, len);
+		put_unaligned_be16(crc, data + len);
+	} else {
+		pktlen = sizeof(struct ratp_header);
+		control |= RATP_CONTROL_SO;
+		len = 0;
+	}
+
+	ratp_create_packet(ri, hdr, control, len);
+
+	ri->retransmission_count = 0;
+
+	ratp_send_pkt(ri, msg->buf, pktlen);
+
+	return 0;
+}
+
+static void ratp_start_time_wait_timer(struct ratp_internal *ri)
+{
+	ri->timewait_timer_start = get_time_ns();
+}
+
+static void ratp_msg_done(struct ratp_internal *ri, struct ratp_message *msg, int status)
+{
+	int alpha, beta, rtt;
+
+	if (!status) {
+		rtt = (unsigned long)(get_time_ns() - ri->retransmission_timer_start) / MSECOND;
+
+		alpha = 8;
+		beta = 15;
+
+		ri->srtt = (alpha * ri->srtt + (10 - alpha) * rtt) / 10;
+		ri->rto = max(200, beta * ri->srtt / 10);
+
+		pr_debug("%s: done. SRTT: %dms RTO: %dms status: %d\n",
+			__func__, ri->srtt, ri->rto, ri->status);
+	}
+
+	if (msg->complete)
+		msg->complete(msg->complete_ctx, status);
+
+	free(msg->buf);
+	free(msg);
+}
+
+/*
+ * This procedure details the behavior of the LISTEN state.  First
+ * check the packet for the RST flag.  If it is set then packet is
+ * discarded and ignored, return and continue the processing
+ * associated with this state.
+ *
+ * We assume now that the RST flag was not set.  Check the packet
+ * for the ACK flag.  If it is set we have an illegal condition
+ * since no connection has yet been opened.  Send a RST packet
+ * with the correct response SN value:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * Return to the current state without any further processing.
+ *
+ * We assume now that neither the RST nor the ACK flags were set.
+ * Check the packet for a SYN flag.  If it is set then an attempt
+ * is being made to open a connection.  Create a TCB for this
+ * connection.  The sender has placed its MDL in the LENGTH field,
+ * also specified is the sender's initial SN value.  Retrieve and
+ * place them into the TCB.  Note that the presence of the SO flag
+ * is ignored since it has no meaning when either of the SYN, RST,
+ * or FIN flags are set.
+ *
+ * Send a SYN packet which acknowledges the SYN received.  Choose
+ * the initial SN value and the MDL for this end of the
+ * connection:
+ *
+ * <SN=0><AN=received SN+1 modulo 2><CTL=SYN, ACK><LENGTH=MDL>
+ *
+ * and go to the RATP_STATE_SYN_RECEIVED state without any further
+ * processing.
+ *
+ * Any packet not satisfying the above tests is discarded and
+ * ignored.  Return to the current state without any further
+ * processing.
+ */
+static void ratp_behaviour_a(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (hdr->control & RATP_CONTROL_RST)
+		return;
+
+	if (hdr->control & RATP_CONTROL_ACK) {
+		uint8_t control = RATP_CONTROL_RST;
+
+		if (hdr->control & RATP_CONTROL_AN)
+			control |= RATP_CONTROL_SN;
+
+		ratp_send_hdr(ri, control);
+
+		return;
+	}
+
+	if (hdr->control & RATP_CONTROL_SYN) {
+		struct ratp_header synack = {};
+		uint8_t control = RATP_CONTROL_SYN | RATP_CONTROL_ACK;
+
+		if (!(hdr->control & RATP_CONTROL_SN))
+			control |= RATP_CONTROL_AN;
+
+		ratp_create_packet(ri, &synack, control, 255);
+		ratp_send_pkt(ri, &synack, sizeof(synack));
+
+		ratp_state_change(ri, RATP_STATE_SYN_RECEIVED);
+	}
+}
+
+/*
+ * This procedure represents the behavior of the SYN-SENT state
+ * and is entered when this end of the connection decides to
+ * execute an active OPEN.
+ *
+ * First, check the packet for the ACK flag.  If the ACK flag is
+ * set then check to see if the AN value was as expected.  If it
+ * was continue below.  Otherwise the AN value was unexpected.  If
+ * the RST flag was set then discard the packet and return to the
+ * current state without any further processing, else send a
+ * reset:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * Discard the packet and return to the current state without any
+ * further processing.
+ *
+ * At this point either the ACK flag was set and the AN value was
+ * as expected or ACK was not set.  Second, check the RST flag.
+ * If the RST flag is set there are two cases:
+ *
+ * . If the ACK flag is set then discard the packet, flush the
+ * retransmission queue, inform the user "Error: Connection
+ * refused", delete the TCB, and go to the CLOSED state without
+ * any further processing.
+ *
+ * 2. If the ACK flag was not set then discard the packet and
+ * return to this state without any further processing.
+ *
+ * At this point we assume the packet contained an ACK which was
+ * Ok, or there was no ACK, and there was no RST.  Now check the
+ * packet for the SYN flag.  If the ACK flag was set then our SYN
+ * has been acknowledged.  Store MDL received in the TCB.  At this
+ * point we are technically in the ESTABLISHED state.  Send an
+ * acknowledgment packet and any initial data which is queued to
+ * send:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK><DATA>
+ *
+ * Go to the ESTABLISHED state without any further processing.
+ *
+ * If the SYN flag was set but the ACK was not set then the other
+ * end of the connection has executed an active open also.
+ * Acknowledge the SYN, choose your MDL, and send:
+ *
+ * <SN=0><AN=received SN+1 modulo 2><CTL=SYN, ACK><LENGTH=MDL>
+ *
+ * Go to the SYN-RECEIVED state without any further processing.
+ *
+ * Any packet not satisfying the above tests is discarded and
+ * ignored.  Return to the current state without any further
+ * processing.
+ */
+static void ratp_behaviour_b(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if ((hdr->control & RATP_CONTROL_ACK) && !ratp_an_expected(ri, hdr)) {
+		if (!(hdr->control & RATP_CONTROL_RST)) {
+			uint8_t control = RATP_CONTROL_RST;
+
+			control = RATP_CONTROL_RST |
+				ratp_set_sn(ratp_an(hdr));
+
+			ratp_send_hdr(ri, control);
+		}
+		return;
+	}
+
+	if (hdr->control & RATP_CONTROL_RST) {
+		if (hdr->control & RATP_CONTROL_ACK) {
+			ri->status = -ECONNREFUSED;
+
+			pr_debug("Connection refused\n");
+
+			ratp_state_change(ri, RATP_STATE_CLOSED);
+
+		}
+		return;
+	}
+
+	if (hdr->control & RATP_CONTROL_SYN) {
+		uint8_t control;
+
+		if (hdr->control & RATP_CONTROL_ACK) {
+			control = ratp_set_sn(ratp_an(hdr)) |
+				ratp_set_an(!ratp_sn(hdr)) |
+				RATP_CONTROL_ACK;
+		} else {
+			control = ratp_set_an(!ratp_sn(hdr)) |
+				RATP_CONTROL_SYN |
+				RATP_CONTROL_ACK;
+
+		}
+
+		ri->sn_received = ratp_sn(hdr);
+
+		ratp_send_hdr(ri, control);
+		ratp_state_change(ri, RATP_STATE_ESTABLISHED);
+	}
+}
+
+/*
+ * Examine the received SN field value.  If the SN value was
+ * expected then return and continue the processing associated
+ * with this state.
+ *
+ * We now assume the SN value was not what was expected.
+ *
+ * If either RST or FIN were set discard the packet and return to
+ * the current state without any further processing.
+ *
+ * If neither RST nor FIN flags were set it is assumed that this
+ * packet is a duplicate of one already received.  Send an ACK
+ * back:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * Discard the duplicate packet and return to the current state
+ * without any further processing.
+ */
+static int ratp_behaviour_c1(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	int ret;
+
+	pr_debug("%s\n", __func__);
+
+	if (ratp_sn_expected(ri, hdr)) {
+		pr_vdebug("%s: sn is expected\n", __func__);
+		return 0;
+	}
+
+	if (!(hdr->control & RATP_CONTROL_RST) &&
+			!(hdr->control & RATP_CONTROL_FIN)) {
+		ret = ratp_send_ack(ri, hdr);
+		if (ret)
+			return ret;
+	}
+
+	return 1;
+
+}
+
+/*
+ * Examine the received SN field value.  If the SN value was
+ * expected then return and continue the processing associated
+ * with this state.
+ *
+ * We now assume the SN value was not what was expected.
+ *
+ * If either RST or FIN were set discard the packet and return to
+ * the current state without any further processing.
+ *
+ * If SYN was set we assume that the other end crashed and has
+ * attempted to open a new connection.  We respond by sending a
+ * legal reset:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=RST, ACK>
+ *
+ * This will cause the other end, currently in the SYN-SENT state,
+ * to close.  Flush the retransmission queue, inform the user
+ * "Error: Connection reset", discard the packet, delete the TCB,
+ * and go to the CLOSED state without any further processing.
+ *
+ * If neither RST, FIN, nor SYN flags were set it is assumed that
+ * this packet is a duplicate of one already received.  Send an
+ * ACK back:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * Discard the duplicate packet and return to the current state
+ * without any further processing.
+ */
+static int ratp_behaviour_c2(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	int ret;
+
+	pr_debug("%s\n", __func__);
+
+	if (!ratp_has_data(hdr))
+		return 0;
+
+	if (ratp_sn_expected(ri, hdr))
+		return 0;
+
+	if ((hdr->control & RATP_CONTROL_RST) ||
+			(hdr->control & RATP_CONTROL_FIN))
+		return 1;
+
+	if (hdr->control & RATP_CONTROL_SYN) {
+		ri->status = -ECONNRESET;
+		pr_debug("Error: Connection reset\n");
+		ratp_state_change(ri, RATP_STATE_CLOSED);
+		return 1;
+	}
+
+	if (!ratp_has_data(hdr))
+		return 1;
+
+	pr_debug("Sending ack for duplicate message\n");
+	ret = ratp_send_ack(ri, hdr);
+	if (ret)
+		return ret;
+
+	return 1;
+}
+
+/*
+ * The packet is examined for a RST flag.  If RST is not set then
+ * return and continue the processing associated with this state.
+ *
+ * RST is now assumed to have been set.  If the connection was
+ * originally initiated from the LISTEN state (it was passively
+ * opened) then flush the retransmission queue, discard the
+ * packet, and go to the LISTEN state without any further
+ * processing.
+ *
+ * If instead the connection was initiated actively (came from the
+ * SYN-SENT state) then flush the retransmission queue, inform the
+ * user "Error: Connection refused", discard the packet, delete
+ * the TCB, and go to the CLOSED state without any further
+ * processing.
+ */
+static int ratp_behaviour_d1(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_RST))
+		return 0;
+
+	if (!(ri->active)) {
+		ratp_state_change(ri, RATP_STATE_LISTEN);
+		return 1;
+	}
+
+	ri->status = -ECONNREFUSED;
+
+	pr_debug("Error: connection refused\n");
+
+	ratp_state_change(ri, RATP_STATE_CLOSED);
+
+	return 1;
+}
+
+/*
+ * The packet is examined for a RST flag.  If RST is not set then
+ * return and continue the processing associated with this state.
+ *
+ * RST is now assumed to have been set.  Any data remaining to be
+ * sent is flushed.  The retransmission queue is flushed, the user
+ * is informed "Error: Connection reset.", discard the packet,
+ * delete the TCB, and go to the CLOSED state without any further
+ * processing.
+ */
+static int ratp_behaviour_d2(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_RST))
+		return 0;
+
+	ri->status = -ECONNRESET;
+
+	pr_debug("connection reset\n");
+
+	return 0;
+}
+
+/*
+ * The packet is examined for a RST flag.  If RST is not set then
+ * return and continue the processing associated with this state.
+ *
+ * RST is now assumed to have been set.  Discard the packet,
+ * delete the TCB, and go to the CLOSED state without any further
+ * processing.
+ */
+static int ratp_behaviour_d3(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_RST))
+		return 0;
+
+	ratp_state_change(ri, RATP_STATE_CLOSED);
+
+	return 1;
+}
+
+/*
+ * Check the presence of the SYN flag.  If the SYN flag is not set
+ * then return and continue the processing associated with this
+ * state.
+ *
+ * We now assume that the SYN flag was set.  The presence of a SYN
+ * here is an error.  Flush the retransmission queue, send a legal
+ * RST packet.
+ *
+ * If the ACK flag was set then send:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * If the ACK flag was not set then send:
+ *
+ * <SN=0><CTL=RST>
+ *
+ * The user should receive the message "Error: Connection reset.",
+ * then delete the TCB and go to the CLOSED state without any
+ * further processing.
+ */
+static int ratp_behaviour_e(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_SYN))
+		return 0;
+
+	ri->status = -ECONNRESET;
+
+	control = RATP_CONTROL_RST;
+
+	if (hdr->control & RATP_CONTROL_ACK)
+		control |= ratp_set_sn(ratp_an(hdr));
+
+	ratp_send_hdr(ri, control);
+
+	pr_debug("connection reset\n");
+
+	ratp_state_change(ri, RATP_STATE_CLOSED);
+
+	return 1;
+}
+
+/*
+ * Check the presence of the ACK flag.  If ACK is not set then
+ * discard the packet and return without any further processing.
+ *
+ * We now assume that the ACK flag was set.  If the AN field value
+ * was as expected then return and continue the processing
+ * associated with this state.
+ *
+ * We now assume that the ACK flag was set and that the AN field
+ * value was unexpected.  If the connection was originally
+ * initiated from the LISTEN state (it was passively opened) then
+ * flush the retransmission queue, discard the packet, and send a
+ * legal RST packet:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * Then delete the TCB and go to the LISTEN state without any
+ * further processing.
+ *
+ * Otherwise the connection was initiated actively (came from the
+ * SYN-SENT state) then inform the user "Error: Connection
+ * refused", flush the retransmission queue, discard the packet,
+ * and send a legal RST packet:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * Then delete the TCB and go to the CLOSED state without any
+ * further processing.
+ */
+static int ratp_behaviour_f1(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_ACK))
+		return 1;
+
+	if (ratp_an_expected(ri, hdr))
+		return 0;
+
+	control = RATP_CONTROL_RST | ratp_set_sn(ratp_an(hdr));
+	ratp_send_hdr(ri, control);
+
+	if (ri->active) {
+		ratp_state_change(ri, RATP_STATE_CLOSED);
+		ri->status = -ECONNREFUSED;
+
+		pr_debug("connection refused\n");
+	} else {
+		ratp_state_change(ri, RATP_STATE_LISTEN);
+	}
+
+	return 1;
+}
+
+/*
+ * Check the presence of the ACK flag.  If ACK is not set then
+ * discard the packet and return without any further processing.
+ *
+ * We now assume that the ACK flag was set.  If the AN field value
+ * was as expected then flush the retransmission queue and inform
+ * the user with an "Ok" if a buffer has been entirely
+ * acknowledged.  Another packet containing data may now be sent.
+ * Return and continue the processing associated with this state.
+ *
+ * We now assume that the ACK flag was set and that the AN field
+ * value was unexpected.  This is assumed to indicate a duplicate
+ * acknowledgment.  It is ignored, return and continue the
+ * processing associated with this state.
+ */
+static int ratp_behaviour_f2(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_ACK))
+		return 1;
+
+	if (ratp_an_expected(ri, hdr)) {
+		pr_debug("Data succesfully sent\n");
+		if (ri->sendmsg_current)
+			ratp_msg_done(ri, ri->sendmsg_current, 0);
+		ri->sendmsg_current = NULL;
+		return 0;
+	} else {
+		pr_vdebug("%s: an not expected\n", __func__);
+	}
+
+	return 0;
+}
+
+/*
+ * Check the presence of the ACK flag.  If ACK is not set then
+ * discard the packet and return without any further processing.
+ *
+ * We now assume that the ACK flag was set.  If the AN field value
+ * was as expected then continue the processing associated with
+ * this state.
+ *
+ * We now assume that the ACK flag was set and that the AN field
+ * value was unexpected.  This is ignored, return and continue
+ * with the processing associated with this state.
+ */
+static int ratp_behaviour_f3(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_ACK))
+		return 1;
+
+	return 0;
+}
+
+/*
+ * This procedure represents the behavior of the CLOSED state of a
+ * connection.  All incoming packets are discarded.  If the packet
+ * had the RST flag set take no action.  Otherwise it is necessary
+ * to build a RST packet.  Since this end is closed the other end
+ * of the connection has incorrect data about the state of the
+ * connection and should be so informed.
+ *
+ * If the ACK flag was set then send:
+ *
+ * <SN=received AN><CTL=RST>
+ *
+ * If the ACK flag was not set then send:
+ *
+ * <SN=0><AN=received SN+1 modulo 2><CTL=RST, ACK>
+ *
+ * After sending the reset packet return to the current state
+ * without any further processing.
+ */
+static int ratp_behaviour_g(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+
+	pr_debug("%s\n", __func__);
+
+	control = RATP_CONTROL_RST;
+
+	if (hdr->control & RATP_CONTROL_ACK)
+		control |= ratp_set_sn(ratp_an(hdr));
+	else
+		control = ratp_set_an(ratp_sn(hdr) + 1) | RATP_CONTROL_ACK;
+
+	ratp_send_hdr(ri, control);
+
+	return 0;
+}
+
+/*
+ * Our SYN has been acknowledged.  At this point we are
+ * technically in the ESTABLISHED state.  Send any initial data
+ * which is queued to send:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK><DATA>
+ *
+ * Go to the ESTABLISHED state and execute procedure I1 to process
+ * any data which might be in this packet.
+ *
+ * Any packet not satisfying the above tests is discarded and
+ * ignored.  Return to the current state without any further
+ * processing.
+ */
+static int ratp_behaviour_h1(struct ratp_internal *ri, void *pkt)
+{
+	pr_debug("%s\n", __func__);
+
+	ratp_state_change(ri, RATP_STATE_ESTABLISHED);
+
+	return 0;
+}
+
+/*
+ * Check the presence of the FIN flag.  If FIN is not set then
+ * continue the processing associated with this state.
+ *
+ * We now assume that the FIN flag was set.  This means the other
+ * end has decided to close the connection.  Flush the
+ * retransmission queue.  If any data remains to be sent then
+ * inform the user "Warning: Data left unsent."  The user must
+ * also be informed "Connection closing."  An acknowledgment for
+ * the FIN must be sent which also indicates this end is closing:
+ *
+ * <SN=received AN><AN=received SN + 1 modulo 2><CTL=FIN, ACK>
+ *
+ * Go to the LAST-ACK state without any further processing.
+ */
+static int ratp_behaviour_h2(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_FIN))
+		return 0;
+
+	ri->status = -ENETDOWN;
+
+	control = ratp_set_sn(ratp_an(hdr)) |
+		ratp_set_an(ratp_sn(hdr) + 1) |
+		RATP_CONTROL_FIN |
+		RATP_CONTROL_ACK;
+
+	ratp_send_hdr(ri, control);
+
+	ratp_state_change(ri, RATP_STATE_LAST_ACK);
+
+	return 1;
+}
+
+/*
+ * This state represents the final behavior of the FIN-WAIT state.
+ *
+ * If the packet did not contain a FIN we assume this packet is a
+ * duplicate and that the other end of the connection has not seen
+ * the FIN packet we sent earlier.  Rely upon retransmission of
+ * our earlier FIN packet to inform the other end of our desire to
+ * close.  Discard the packet and return without any further
+ * processing.
+ *
+ * At this point we have a packet which should contain a FIN.  By
+ * the rules of this protocol an ACK of a FIN requires a FIN, ACK
+ * in response and no data.  If the packet contains data we have
+ * detected an illegal condition.  Send a reset:
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=RST, ACK>
+ *
+ * Discard the packet, flush the retransmission queue, inform the
+ * ser "Error: Connection reset.", delete the TCB, and go to the
+ * CLOSED state without any further processing.
+ *
+ * We now assume that the FIN flag was set and no data was
+ * contained in the packet.  If the AN field value was expected
+ * then this packet acknowledges a previously sent FIN packet.
+ * The other end of the connection is then also assumed to be
+ * closing and expects an acknowledgment.  Send an acknowledgment
+ * of the FIN:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * Start the 2*SRTT timer associated with the TIME-WAIT state,
+ * discard the packet, and go to the TIME-WAIT state without any
+ * further processing.
+ *
+ * Otherwise the AN field value was unexpected.  This indicates a
+ * simultaneous closing by both sides of the connection.  Send an
+ * acknowledgment of the FIN:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * Discard the packet, and go to the CLOSING state without any
+ * further processing.
+ */
+static int ratp_behaviour_h3(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+	int expected;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_FIN))
+		return 1;
+
+	if (ratp_has_data(hdr)) {
+		control = ratp_set_sn(ratp_an(hdr)) |
+			ratp_set_an(ratp_sn(hdr) + 1) |
+			RATP_CONTROL_RST |
+			RATP_CONTROL_ACK;
+		ratp_send_hdr(ri, control);
+		ri->status = -ECONNRESET;
+		pr_debug("Error: Connection reset\n");
+		ratp_state_change(ri, RATP_STATE_CLOSED);
+		return 1;
+	}
+
+	control = ratp_set_sn(ratp_an(hdr)) |
+		ratp_set_an(ratp_sn(hdr) + 1) |
+		RATP_CONTROL_ACK;
+
+	expected = ratp_an_expected(ri, hdr);
+
+	ratp_send_hdr(ri, control);
+
+	if (expected) {
+		ratp_state_change(ri, RATP_STATE_TIME_WAIT);
+		ratp_start_time_wait_timer(ri);
+	} else {
+		ratp_state_change(ri, RATP_STATE_CLOSING);
+	}
+
+	return 1;
+}
+
+/*
+ * This state represents the final behavior of the LAST-ACK state.
+ *
+ * If the AN field value is expected then this ACK is in response
+ * to the FIN, ACK packet recently sent.  This is the final
+ * acknowledging message indicating both side's agreement to close
+ * the connection.  Discard the packet, flush all queues, delete
+ * the TCB, and go to the CLOSED state without any further
+ * processing.
+ *
+ * Otherwise the AN field value was unexpected.  Discard the
+ * packet and remain in the current state without any further
+ * processing.
+ */
+static int ratp_behaviour_h4(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (ratp_an_expected(ri, hdr))
+		ratp_state_change(ri, RATP_STATE_CLOSED);
+
+	return 1;
+}
+
+/*
+ * This state represents the final behavior of the CLOSING state.
+ *
+ * If the AN field value was expected then this packet
+ * acknowledges the FIN packet recently sent.  This is the final
+ * acknowledging message indicating both side's agreement to close
+ * the connection.  Start the 2*SRTT timer associated with the
+ * TIME-WAIT state, discard the packet, and go to the TIME-WAIT
+ * state without any further processing.
+ *
+ * Otherwise the AN field value was unexpected.  Discard the
+ * packet and remain in the current state without any further
+ * processing.
+ */
+static int ratp_behaviour_h5(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+
+	pr_debug("%s\n", __func__);
+
+	if (ratp_an_expected(ri, hdr)) {
+		ratp_state_change(ri, RATP_STATE_TIME_WAIT);
+		ratp_start_time_wait_timer(ri);
+	}
+
+	return 0;
+}
+
+/*
+ * This state represents the behavior of the TIME-WAIT state.
+ * Check the presence of the ACK flag.  If ACK is not set then
+ * discard the packet and return without any further processing.
+ *
+ * Check the presence of the FIN flag.  If FIN is not set then
+ * discard the packet and return without any further processing.
+ *
+ * We now assume that the FIN flag was set.  This situation
+ * indicates that the last acknowledgment of the FIN packet sent
+ * by the other end of the connection did not arrive.  Resend the
+ * acknowledgment:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * Restart the 2*SRTT timer, discard the packet, and remain in the
+ * current state without any further processing.
+ */
+static int ratp_behaviour_h6(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control;
+
+	pr_debug("%s\n", __func__);
+
+	if (!(hdr->control & RATP_CONTROL_ACK))
+		return 1;
+
+	if (!(hdr->control & RATP_CONTROL_FIN))
+		return 1;
+
+	control = ratp_set_sn(ratp_an(hdr) + 1) | RATP_CONTROL_ACK;
+
+	ratp_send_hdr(ri, control);
+
+	ratp_start_time_wait_timer(ri);
+
+	return 0;
+}
+
+static int msg_recv(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	struct ratp_message *msg;
+
+	pr_debug("%s: Put msg in receive queue\n", __func__);
+
+	msg = xzalloc(sizeof(*msg));
+	if (hdr->data_length) {
+		msg->len = hdr->data_length;
+		msg->buf = xzalloc(msg->len);
+		memcpy(msg->buf, pkt + sizeof(struct ratp_header), msg->len);
+	} else {
+		msg->len = 1;
+		msg->buf = xzalloc(1);
+		*(uint8_t *)msg->buf = hdr->data_length;
+	}
+
+	if (hdr->control & RATP_CONTROL_EOR)
+		msg->eor = 1;
+
+	list_add_tail(&msg->list, &ri->recvmsg);
+
+	return 0;
+}
+
+/*
+ * This represents that stage of processing in the ESTABLISHED
+ * state in which all the flag bits have been processed and only
+ * data may remain.  The packet is examined to see if it contains
+ * data.  If not the packet is now discarded, return to the
+ * current state without any further processing.
+ *
+ * We assume the packet contained data, that either the SO flag
+ * was set or LENGTH is positive.  That data is placed into the
+ * user's receive buffers.  As these become full the user should
+ * be informed "Receive buffer full."  An acknowledgment is sent:
+ *
+ * <SN=received AN><AN=received SN+1 modulo 2><CTL=ACK>
+ *
+ * If data is queued to send then it is most efficient to
+ * 'piggyback' this acknowledgment on that data packet.
+ *
+ * The packet is now discarded, return to the ESTABLISHED state
+ * without any further processing.
+ */
+static int ratp_behaviour_i1(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	uint8_t control = 0;
+
+	if (!hdr->data_length && !(hdr->control & RATP_CONTROL_SO))
+		return 1;
+
+	pr_vdebug("%s **received** %d\n", __func__, hdr->data_length);
+
+	ri->sn_received = ratp_sn(hdr);
+
+	msg_recv(ri, pkt);
+
+	if (list_empty(&ri->sendmsg) || ri->sendmsg_current) {
+		control = ratp_set_sn(!ri->sn_sent) |
+			ratp_set_an(ri->sn_received + 1) |
+			RATP_CONTROL_ACK;
+
+		ratp_send_hdr(ri, control);
+	} else {
+		ratp_send_next_data(ri);
+	}
+
+	return 0;
+}
+
+/*
+ * State machine as desribed in RFC916
+ *
+ * STATE                BEHAVIOR
+ * =============+========================
+ * LISTEN       |  A
+ * -------------+------------------------
+ * SYN-SENT     |  B
+ * -------------+------------------------
+ * SYN-RECEIVED |  C1  D1  E  F1  H1
+ * -------------+------------------------
+ * ESTABLISHED  |  C2  D2  E  F2  H2  I1
+ * -------------+------------------------
+ * FIN-WAIT     |  C2  D2  E  F3  H3
+ * -------------+------------------------
+ * LAST-ACK     |  C2  D3  E  F3  H4
+ * -------------+------------------------
+ * CLOSING      |  C2  D3  E  F3  H5
+ * -------------+------------------------
+ * TIME-WAIT    |  D3  E  F3 H6
+ * -------------+------------------------
+ * CLOSED       |  G
+ * -------------+------------------------
+ */
+
+static int ratp_state_machine(struct ratp_internal *ri, void *pkt)
+{
+	struct ratp_header *hdr = pkt;
+	int ret;
+
+	ratp_print_header(ri, hdr, "                      recv");
+	pr_debug(" state %s\n", ratp_state_str[ri->state]);
+
+	switch (ri->state) {
+	case RATP_STATE_LISTEN:
+		ratp_behaviour_a(ri, pkt);
+		break;
+	case RATP_STATE_SYN_SENT:
+		ratp_behaviour_b(ri, pkt);
+		break;
+	case RATP_STATE_SYN_RECEIVED:
+		ret = ratp_behaviour_c1(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_d1(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f1(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h1(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_ESTABLISHED:
+		ret = ratp_behaviour_c2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_d2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_i1(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_FIN_WAIT:
+		ret = ratp_behaviour_c2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_d2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h3(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_LAST_ACK:
+		ret = ratp_behaviour_c2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_d3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h4(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_CLOSING:
+		ret = ratp_behaviour_c2(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_d3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h5(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_TIME_WAIT:
+		ret = ratp_behaviour_d3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_e(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_f3(ri, pkt);
+		if (ret)
+			return ret;
+		ret = ratp_behaviour_h6(ri, pkt);
+		if (ret)
+			return ret;
+		break;
+	case RATP_STATE_CLOSED:
+		ratp_behaviour_g(ri, pkt);
+		break;
+	};
+
+	return 0;
+}
+
+/**
+ * ratp_closed() - Check if a connection is closed
+ *
+ * Return: true if a connection is closed, false otherwise
+ */
+bool ratp_closed(struct ratp *ratp)
+{
+	struct ratp_internal *ri = ratp->internal;
+
+	if (!ri)
+		return true;
+
+	return ri->state == RATP_STATE_CLOSED;
+}
+
+/**
+ * ratp_busy() - Check if we are inside the RATP code
+ *
+ * Needed for RATP debugging. The RATP console uses this to determine
+ * if it is called from inside the RATP code.
+ *
+ * Return: true if we are inside the RATP code, false otherwise
+ */
+bool ratp_busy(struct ratp *ratp)
+{
+	struct ratp_internal *ri = ratp->internal;
+
+	if (!ri)
+		return false;
+
+	return ri->in_ratp != 0;
+}
+
+/**
+ * ratp_poll() - Execute RATP state machine
+ * @ratp: The RATP link
+ *
+ * This function should be executed periodically to keep the RATP state
+ * machine going.
+ *
+ * Return: 0 if successful, a negative error code otherwise.
+ */
+int ratp_poll(struct ratp *ratp)
+{
+	struct ratp_internal *ri = ratp->internal;
+	int ret;
+
+	if (!ri)
+		return -ENETDOWN;
+
+	ri->in_ratp++;
+
+	ret = ratp_recv_pkt(ri, ri->recvbuf, 100);
+	if (ret == 0) {
+
+		if (ri->state == RATP_STATE_TIME_WAIT &&
+		    is_timeout(ri->timewait_timer_start, ri->srtt * 2 * MSECOND)) {
+			pr_debug("2*SRTT timer timed out\n");
+			ret = -ECONNRESET;
+			goto out;
+		}
+
+		ret = ratp_state_machine(ri, ri->recvbuf);
+		if (ret < 0)
+			goto out;
+
+		if (ri->status < 0) {
+			ret = ri->status;
+			goto out;
+		}
+	}
+
+	if (ri->sendmsg_current && is_timeout(ri->retransmission_timer_start,
+	    ri->rto * MSECOND)) {
+
+		ri->retransmission_count++;
+		if (ri->retransmission_count == ri->max_retransmission) {
+			ri->status = ret = -ETIMEDOUT;
+			ri->state = RATP_STATE_CLOSED;
+			goto out;
+		}
+
+		pr_debug("%s: retransmit\n", __func__);
+
+		ratp_print_header(ri, ri->sendbuf, "resend");
+
+		ri->retransmission_timer_start = get_time_ns();
+
+		ret = ri->ratp->send(ratp, ri->sendbuf, ri->sendbuf_len);
+		if (ret)
+			goto out;
+	}
+
+	if (!ri->sendmsg_current && !list_empty(&ri->sendmsg))
+		ratp_send_next_data(ri);
+
+	ret = 0;
+out:
+	ri->in_ratp--;
+
+	return ret;
+}
+
+/**
+ * ratp_establish(): Establish a RATP link
+ * @ratp: The RATP link
+ * @active: if true actively create a connection
+ * @timeout_ms: Timeout in ms to wait until a connection is established. If
+ *              0 wait forever.
+ *
+ * This function establishes a link with the remote end. It expects the
+ * send and receive functions to be set, all other struct ratp_internal members can
+ * be left uninitialized.
+ *
+ * Return: 0 if successful, a negative error code otherwise.
+ */
+int ratp_establish(struct ratp *ratp, bool active, int timeout_ms)
+{
+	struct ratp_internal *ri;
+	int ret;
+	uint64_t start;
+
+	ri = xzalloc(sizeof(*ri));
+	ri->ratp = ratp;
+	ratp->internal = ri;
+
+	ri->recvbuf = xmalloc(512);
+	ri->sendbuf = xmalloc(512);
+	INIT_LIST_HEAD(&ri->recvmsg);
+	INIT_LIST_HEAD(&ri->sendmsg);
+	ri->max_retransmission = 100;
+	ri->srtt = 100;
+	ri->rto = 100;
+	ri->active = active;
+
+	ri->in_ratp++;
+
+	if (ri->active) {
+		ratp_send_hdr(ri, RATP_CONTROL_SYN);
+
+		ratp_state_change(ri, RATP_STATE_SYN_SENT);
+	}
+
+	start = get_time_ns();
+
+	while (1) {
+		ret = ratp_poll(ri->ratp);
+		if (ret < 0)
+			goto out;
+
+		if (ri->state == RATP_STATE_ESTABLISHED) {
+			ret = 0;
+			goto out;
+		}
+
+		if (timeout_ms && is_timeout(start, MSECOND * timeout_ms)) {
+			ret = -ETIMEDOUT;
+			goto out;
+		}
+	}
+
+out:
+	if (ret) {
+		free(ri->recvbuf);
+		free(ri->sendbuf);
+		free(ri);
+		ratp->internal = NULL;
+	}
+
+	ri->in_ratp--;
+
+	return ret;
+}
+
+void ratp_close(struct ratp *ratp)
+{
+	struct ratp_internal *ri = ratp->internal;
+	struct ratp_message *msg, *tmp;
+	struct ratp_header fin = {};
+
+	if (!ri)
+		return;
+
+	if (ri->state == RATP_STATE_ESTABLISHED) {
+		uint64_t start;
+		u8 control;
+
+		pr_debug("Closing...\n");
+
+		ratp_state_change(ri, RATP_STATE_FIN_WAIT);
+
+		control = ratp_set_sn(!ri->sn_sent) |
+			ratp_set_an(ri->sn_received + 1) |
+			RATP_CONTROL_FIN | RATP_CONTROL_ACK;
+
+		ratp_create_packet(ri, &fin, control, 0);
+
+		ratp_send_pkt(ri, &fin, sizeof(fin));
+
+		start = get_time_ns();
+
+		while (!is_timeout(start, ri->srtt * MSECOND * 2))
+			ratp_poll(ratp);
+	}
+
+	list_for_each_entry_safe(msg, tmp, &ri->sendmsg, list)
+		ratp_msg_done(ri, msg, -ECONNRESET);
+
+	free(ri);
+	ratp->internal = NULL;
+
+	pr_info("Closed\n");
+}
+
+/**
+ * ratp_send_complete(): Send data over a RATP link
+ * @ratp: The RATP link
+ * @data: The data buffer
+ * @len: The length of the message to send
+ * @complete: The completion callback for the message
+ * @complete_ctx: context pointer for the completion callback
+ *
+ * Queue a RATP message for transmission. This only queues the message,
+ * ratp_poll has to be called to actually transfer the message.
+ * @complete will be called upon completion of the message.
+ *
+ * Return: 0 if successful, a negative error code otherwise.
+ */
+int ratp_send_complete(struct ratp *ratp, const void *data, size_t len,
+		   void (*complete)(void *ctx, int status), void *complete_ctx)
+{
+	struct ratp_internal *ri = ratp->internal;
+	struct ratp_message *msg;
+
+	if (!ri || ri->state != RATP_STATE_ESTABLISHED)
+		return -ENETDOWN;
+
+	if (!len)
+		return -EINVAL;
+
+	ri->in_ratp++;
+
+	while (len) {
+		int now = min((int)len, 255);
+
+		msg = xzalloc(sizeof(*msg));
+		msg->buf = xzalloc(sizeof(struct ratp_header) + now + 2);
+		msg->len = now;
+		memcpy(msg->buf + sizeof(struct ratp_header), data, now);
+
+		list_add_tail(&msg->list, &ri->sendmsg);
+
+		len -= now;
+	}
+
+	msg->eor = 1;
+	msg->complete = complete;
+	msg->complete_ctx = complete_ctx;
+
+	ri->in_ratp--;
+
+	return 0;
+}
+
+/**
+ * ratp_send(): Send data over a RATP link
+ * @ratp: The RATP link
+ * @data: The data buffer
+ * @len: The length of the message to send
+ *
+ * Queue a RATP message for transmission. This only queues the message,
+ * ratp_poll has to be called to actually transfer the message.
+ *
+ * Return: 0 if successful, a negative error code otherwise.
+ */
+int ratp_send(struct ratp *ratp, const void *data, size_t len)
+{
+	return ratp_send_complete(ratp, data, len, NULL, NULL);
+}
+
+/**
+ * ratp_recv() - Receive data from a RATP link
+ * @ratp: The RATP link
+ * @data: Pointer to data
+ * @len: The length of the data in bytes
+ *
+ * If a message is available it fills @data with a pointer to the data.
+ * This function does not wait for new messages. If no data is available
+ * -EAGAIN is returned. If data is received @data has to be freed by the
+ * caller.
+ *
+ * Return: 0 if successful, a negative error code otherwise.
+ */
+int ratp_recv(struct ratp *ratp, void **data, size_t *len)
+{
+	struct ratp_internal *ri = ratp->internal;
+	struct ratp_message *msg, *tmp;
+	void *pos;
+	int num = 0;
+
+	*len = 0;
+
+	if (!ri || ri->state != RATP_STATE_ESTABLISHED)
+		return -ENETDOWN;
+
+	if (list_empty(&ri->recvmsg))
+		return -EAGAIN;
+
+	list_for_each_entry(msg, &ri->recvmsg, list) {
+		*len += msg->len;
+		num++;
+		if (msg->eor)
+			goto eor;
+	}
+
+	return -EAGAIN;
+
+eor:
+	*data = malloc(*len);
+	if (!*data)
+		return -ENOMEM;
+
+	pos = *data;
+
+	list_for_each_entry_safe(msg, tmp, &ri->recvmsg, list) {
+		memcpy(pos, msg->buf, msg->len);
+		pos += msg->len;
+
+		list_del(&msg->list);
+
+		free(msg->buf);
+		free(msg);
+	}
+
+	return 0;
+}
\ No newline at end of file
diff --git a/lib/readline.c b/lib/readline.c
index cac967005f..b5d99ca185 100644
--- a/lib/readline.c
+++ b/lib/readline.c
@@ -2,6 +2,8 @@
 #include <readkey.h>
 #include <init.h>
 #include <libbb.h>
+#include <poller.h>
+#include <ratp.h>
 #include <xfuncs.h>
 #include <complete.h>
 #include <linux/ctype.h>
@@ -198,6 +200,12 @@ int readline(const char *prompt, char *buf, int len)
 	puts (prompt);
 
 	while (1) {
+		while (!tstc()) {
+			poller_call();
+			if (IS_ENABLED(CONFIG_RATP))
+				ratp_run_command();
+		}
+
 		ichar = read_key();
 
 		if ((ichar == '\n') || (ichar == '\r')) {
diff --git a/scripts/bbremote b/scripts/bbremote
new file mode 100755
index 0000000000..bc5351dbae
--- /dev/null
+++ b/scripts/bbremote
@@ -0,0 +1,3 @@
+#!/usr/bin/env python2
+
+import remote.main
diff --git a/scripts/remote/__init__.py b/scripts/remote/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/scripts/remote/__init__.py
diff --git a/scripts/remote/controller.py b/scripts/remote/controller.py
new file mode 100644
index 0000000000..a7257ecc97
--- /dev/null
+++ b/scripts/remote/controller.py
@@ -0,0 +1,173 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, print_function
+
+import struct
+import logging
+import sys
+import os
+from threading import Thread
+from Queue import Queue, Empty
+from .ratpfs import RatpFSServer
+from .messages import *
+from .ratp import RatpError
+
+try:
+    from time import monotonic
+except:
+    from .missing import monotonic
+
+
+def unpack(data):
+    p_type, = struct.unpack("!H", data[:2])
+    logging.debug("unpack: %r data=%r", p_type, repr(data))
+    if p_type == BBType.command:
+        logging.debug("received: command")
+        return BBPacketCommand(raw=data)
+    elif p_type == BBType.command_return:
+        logging.debug("received: command_return")
+        return BBPacketCommandReturn(raw=data)
+    elif p_type == BBType.consolemsg:
+        logging.debug("received: consolemsg")
+        return BBPacketConsoleMsg(raw=data)
+    elif p_type == BBType.ping:
+        logging.debug("received: ping")
+        return BBPacketPing(raw=data)
+    elif p_type == BBType.pong:
+        logging.debug("received: pong")
+        return BBPacketPong(raw=data)
+    elif p_type == BBType.getenv_return:
+        logging.debug("received: getenv_return")
+        return BBPacketGetenvReturn(raw=data)
+    elif p_type == BBType.fs:
+        logging.debug("received: fs")
+        return BBPacketFS(raw=data)
+    elif p_type == BBType.fs_return:
+        logging.debug("received: fs_return")
+        return BBPacketFSReturn(raw=data)
+    else:
+        logging.debug("received: UNKNOWN")
+        return BBPacket(raw=data)
+
+
+class Controller(Thread):
+    def __init__(self, conn):
+        Thread.__init__(self)
+        self.daemon = True
+        self.conn = conn
+        self.fsserver = None
+        self.rxq = None
+        self.conn.connect(timeout=5.0)
+        self._txq = Queue()
+        self._stop = False
+        self.fsserver = RatpFSServer()
+
+    def _send(self, bbpkt):
+        self.conn.send(bbpkt.pack())
+
+    def _handle(self, bbpkt):
+        if isinstance(bbpkt, BBPacketConsoleMsg):
+            os.write(sys.stdout.fileno(), bbpkt.text)
+        elif isinstance(bbpkt, BBPacketPong):
+            print("pong",)
+        elif isinstance(bbpkt, BBPacketFS):
+            if self.fsserver != None:
+                self._send(self.fsserver.handle(bbpkt))
+
+    def _expect(self, bbtype, timeout=1.0):
+        if timeout is not None:
+            limit = monotonic()+timeout
+        while timeout is None or limit > monotonic():
+            pkt = self.conn.recv(0.1)
+            if not pkt:
+                continue
+            bbpkt = unpack(pkt)
+            if isinstance(bbpkt, bbtype):
+                return bbpkt
+            else:
+                self._handle(bbpkt)
+
+    def export(self, path):
+        self.fsserver = RatpFSServer(path)
+
+    def ping(self):
+        self._send(BBPacketPing())
+        r = self._expect(BBPacketPong)
+        logging.info("Ping: %r", r)
+        if not r:
+            return 1
+        else:
+            print("pong")
+            return 0
+
+    def command(self, cmd):
+        self._send(BBPacketCommand(cmd=cmd))
+        r = self._expect(BBPacketCommandReturn, timeout=None)
+        logging.info("Command: %r", r)
+        return r.exit_code
+
+    def getenv(self, varname):
+        self._send(BBPacketGetenv(varname=varname))
+        r = self._expect(BBPacketGetenvReturn)
+        return r.text
+
+    def close(self):
+        self.conn.close()
+
+    def run(self):
+        assert self.rxq is not None
+        try:
+            while not self._stop:
+                # receive
+                pkt = self.conn.recv()
+                if pkt:
+                    bbpkt = unpack(pkt)
+                    if isinstance(bbpkt, BBPacketConsoleMsg):
+                        self.rxq.put((self, bbpkt.text))
+                    else:
+                        self._handle(bbpkt)
+                # send
+                try:
+                    pkt = self._txq.get(block=False)
+                except Empty:
+                    pkt = None
+                if pkt:
+                    self._send(pkt)
+        except RatpError as detail:
+            print("Ratp error:", detail, file=sys.stderr);
+            self.rxq.put((self, None))
+            return
+
+    def start(self, queue):
+        assert self.rxq is None
+        self.rxq = queue
+        Thread.start(self)
+
+    def stop(self):
+        self._stop = True
+        self.join()
+        self._stop = False
+        self.rxq = None
+
+    def send_async(self, pkt):
+        self._txq.put(pkt)
+
+    def send_async_console(self, text):
+        self._txq.put(BBPacketConsoleMsg(text=text))
+
+    def send_async_ping(self):
+        self._txq.put(BBPacketPing())
+
+
+def main():
+    import serial
+    from .ratp import SerialRatpConnection
+    url = "rfc2217://192.168.23.176:3002"
+    port = serial.serial_for_url(url, 115200)
+    conn = SerialRatpConnection(port)
+    ctrl = Controller(conn)
+    return ctrl
+
+if __name__ == "__main__":
+    C = main()
diff --git a/scripts/remote/main.py b/scripts/remote/main.py
new file mode 100644
index 0000000000..bd304723bb
--- /dev/null
+++ b/scripts/remote/main.py
@@ -0,0 +1,168 @@
+#!/usr/bin/env python2
+
+from __future__ import absolute_import, division, print_function
+
+import sys
+import os
+import argparse
+import logging
+from Queue import Queue
+from .ratp import RatpError
+
+try:
+    import serial
+except:
+    print("error: No python-serial package found", file=sys.stderr)
+    exit(2)
+
+
+def versiontuple(v):
+    return tuple(map(int, (v.split("."))))
+
+if versiontuple(serial.VERSION) < (2, 7):
+    print("warning: python-serial package is buggy in RFC2217 mode,",
+          "consider updating to at least 2.7", file=sys.stderr)
+
+from .ratp import SerialRatpConnection
+from .controller import Controller
+from .threadstdio import ConsoleInput
+
+
+def get_controller(args):
+    port = serial.serial_for_url(args.port, args.baudrate)
+    conn = SerialRatpConnection(port)
+
+    while True:
+        try:
+            ctrl = Controller(conn)
+            break
+        except (RatpError):
+            if args.wait == True:
+                pass
+            else:
+                raise
+
+    return ctrl
+
+
+def handle_run(args):
+    ctrl = get_controller(args)
+    ctrl.export(args.export)
+    res = ctrl.command(' '.join(args.arg))
+    if res:
+        res = 1
+    ctrl.close()
+    return res
+
+
+def handle_ping(args):
+    ctrl = get_controller(args)
+    res = ctrl.ping()
+    if res:
+        res = 1
+    ctrl.close()
+    return res
+
+
+def handle_getenv(args):
+    ctrl = get_controller(args)
+    value = ctrl.getenv(' '.join(args.arg))
+    if not value:
+        res = 1
+    else:
+        print(value)
+        res = 0
+    ctrl.close()
+    return res
+
+
+def handle_listen(args):
+    port = serial.serial_for_url(args.port, args.baudrate)
+    conn = SerialRatpConnection(port)
+    conn.listen()
+    while True:
+        conn.wait(None)
+    conn.close()
+
+
+def handle_console(args):
+    queue = Queue()
+    ctrl = get_controller(args)
+    ctrl.export(args.export)
+    ctrl.start(queue)
+    ctrl.send_async_console('\r')
+    cons = ConsoleInput(queue, exit='\x14')  # CTRL-T
+    cons.start()
+    try:
+        while True:
+            src, data = queue.get(block=True)
+            if src == cons:
+                if data is None:  # shutdown
+                    cons.join()
+                    break
+                elif data == '\x10':  # CTRL-P
+                    ctrl.send_async_ping()
+                else:
+                    ctrl.send_async_console(data)
+            elif src == ctrl:
+                if data is None:  # shutdown
+                    sys.exit(1)
+                    break
+                else:
+                    os.write(sys.stdout.fileno(), data)
+        ctrl.stop()
+        ctrl.close()
+    finally:
+        print()
+        print("total retransmits=%i crc-errors=%i" % (
+            ctrl.conn.total_retransmits,
+            ctrl.conn.total_crc_errors))
+
+VERBOSITY = {
+    0: logging.WARN,
+    1: logging.INFO,
+    2: logging.DEBUG,
+    }
+
+parser = argparse.ArgumentParser(prog='bbremote')
+parser.add_argument('-v', '--verbose', action='count', default=0)
+parser.add_argument('--port', type=str, default=os.environ.get('BBREMOTE_PORT', None))
+parser.add_argument('--baudrate', type=int, default=os.environ.get('BBREMOTE_BAUDRATE', 115200))
+parser.add_argument('--export', type=str, default=os.environ.get('BBREMOTE_EXPORT', None))
+parser.add_argument('-w', '--wait', action='count', default=0)
+subparsers = parser.add_subparsers(help='sub-command help')
+
+parser_run = subparsers.add_parser('run', help="run a barebox command")
+parser_run.add_argument('arg', nargs='+', help="barebox command to run")
+parser_run.set_defaults(func=handle_run)
+
+parser_ping = subparsers.add_parser('ping', help="test connection")
+parser_ping.set_defaults(func=handle_ping)
+
+parser_ping = subparsers.add_parser('getenv', help="get a barebox environment variable")
+parser_ping.add_argument('arg', nargs='+', help="variable name")
+parser_ping.set_defaults(func=handle_getenv)
+
+parser_run = subparsers.add_parser('listen', help="listen for an incoming connection")
+parser_run.set_defaults(func=handle_listen)
+
+parser_run = subparsers.add_parser('console', help="connect to the console")
+parser_run.set_defaults(func=handle_console)
+
+args = parser.parse_args()
+logging.basicConfig(level=VERBOSITY[args.verbose],
+                    format='%(levelname)-8s %(module)-8s %(funcName)-16s %(message)s')
+try:
+    res = args.func(args)
+    exit(res)
+except RatpError as detail:
+    print("Ratp error:", detail, file=sys.stderr);
+    exit(127)
+except KeyboardInterrupt:
+    print("\nInterrupted", file=sys.stderr);
+    exit(1)
+#try:
+#    res = args.func(args)
+#except Exception as e:
+#    print("error: failed to establish connection: %s" % e, file=sys.stderr)
+#    exit(2)
diff --git a/scripts/remote/messages.py b/scripts/remote/messages.py
new file mode 100644
index 0000000000..8e8495b12e
--- /dev/null
+++ b/scripts/remote/messages.py
@@ -0,0 +1,154 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, print_function
+
+import struct
+
+
+class BBType(object):
+    command = 1
+    command_return = 2
+    consolemsg = 3
+    ping = 4
+    pong = 5
+    getenv = 6
+    getenv_return = 7
+    fs = 8
+    fs_return = 9
+
+
+class BBPacket(object):
+    def __init__(self, p_type=0, p_flags=0, payload="", raw=None):
+        self.p_type = p_type
+        self.p_flags = p_flags
+        if raw is not None:
+            self.unpack(raw)
+        else:
+            self.payload = payload
+
+    def __repr__(self):
+        return "BBPacket(%i, %i)" % (self.p_type, self.p_flags)
+
+    def _unpack_payload(self, data):
+        self.payload = data
+
+    def _pack_payload(self):
+        return self.payload
+
+    def unpack(self, data):
+        self.p_type, self.p_flags = struct.unpack("!HH", data[:4])
+        self._unpack_payload(data[4:])
+
+    def pack(self):
+        return struct.pack("!HH", self.p_type, self.p_flags) + \
+            self._pack_payload()
+
+
+class BBPacketCommand(BBPacket):
+    def __init__(self, raw=None, cmd=None):
+        self.cmd = cmd
+        super(BBPacketCommand, self).__init__(BBType.command, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketCommand(cmd=%r)" % self.cmd
+
+    def _unpack_payload(self, payload):
+        self.cmd = payload
+
+    def _pack_payload(self):
+        return self.cmd
+
+
+class BBPacketCommandReturn(BBPacket):
+    def __init__(self, raw=None, exit_code=None):
+        self.exit_code = exit_code
+        super(BBPacketCommandReturn, self).__init__(BBType.command_return,
+                                                    raw=raw)
+
+    def __repr__(self):
+        return "BBPacketCommandReturn(exit_code=%i)" % self.exit_code
+
+    def _unpack_payload(self, data):
+        self.exit_code, = struct.unpack("!L", data[:4])
+
+    def _pack_payload(self):
+        return struct.pack("!L", self.exit_code)
+
+
+class BBPacketConsoleMsg(BBPacket):
+    def __init__(self, raw=None, text=None):
+        self.text = text
+        super(BBPacketConsoleMsg, self).__init__(BBType.consolemsg, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketConsoleMsg(text=%r)" % self.text
+
+    def _unpack_payload(self, payload):
+        self.text = payload
+
+    def _pack_payload(self):
+        return self.text
+
+
+class BBPacketPing(BBPacket):
+    def __init__(self, raw=None):
+        super(BBPacketPing, self).__init__(BBType.ping, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketPing()"
+
+
+class BBPacketPong(BBPacket):
+    def __init__(self, raw=None):
+        super(BBPacketPong, self).__init__(BBType.pong, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketPong()"
+
+
+class BBPacketGetenv(BBPacket):
+    def __init__(self, raw=None, varname=None):
+        self.varname = varname
+        super(BBPacketGetenv, self).__init__(BBType.getenv, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketGetenv(varname=%r)" % self.varname
+
+    def _unpack_payload(self, payload):
+        self.varname = payload
+
+    def _pack_payload(self):
+        return self.varname
+
+
+class BBPacketGetenvReturn(BBPacket):
+    def __init__(self, raw=None, text=None):
+        self.text = text
+        super(BBPacketGetenvReturn, self).__init__(BBType.getenv_return,
+                                                   raw=raw)
+
+    def __repr__(self):
+        return "BBPacketGetenvReturn(varvalue=%s)" % self.text
+
+    def _unpack_payload(self, payload):
+        self.text = payload
+
+    def _pack_payload(self):
+        return self.text
+
+
+class BBPacketFS(BBPacket):
+    def __init__(self, raw=None, payload=None):
+        super(BBPacketFS, self).__init__(BBType.fs, payload=payload, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketFS(payload=%r)" % self.payload
+
+
+class BBPacketFSReturn(BBPacket):
+    def __init__(self, raw=None, payload=None):
+        super(BBPacketFSReturn, self).__init__(BBType.fs_return, payload=payload, raw=raw)
+
+    def __repr__(self):
+        return "BBPacketFSReturn(payload=%r)" % self.payload
diff --git a/scripts/remote/missing.py b/scripts/remote/missing.py
new file mode 100644
index 0000000000..67c2dfa8c0
--- /dev/null
+++ b/scripts/remote/missing.py
@@ -0,0 +1,28 @@
+#!/usr/bin/env python
+
+import ctypes
+import os
+
+CLOCK_MONOTONIC_RAW = 4  # from <linux/time.h>
+
+
+class timespec(ctypes.Structure):
+    _fields_ = [
+        ('tv_sec', ctypes.c_long),
+        ('tv_nsec', ctypes.c_long)
+    ]
+
+librt = ctypes.CDLL('librt.so.1', use_errno=True)
+clock_gettime = librt.clock_gettime
+clock_gettime.argtypes = [ctypes.c_int, ctypes.POINTER(timespec)]
+
+
+def monotonic():
+    t = timespec()
+    if clock_gettime(CLOCK_MONOTONIC_RAW, ctypes.pointer(t)) != 0:
+        errno_ = ctypes.get_errno()
+        raise OSError(errno_, os.strerror(errno_))
+    return t.tv_sec + t.tv_nsec * 1e-9
+
+if __name__ == "__main__":
+    print monotonic()
diff --git a/scripts/remote/ratp.py b/scripts/remote/ratp.py
new file mode 100644
index 0000000000..079fb871a3
--- /dev/null
+++ b/scripts/remote/ratp.py
@@ -0,0 +1,773 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, print_function
+
+import crcmod
+import logging
+import struct
+from enum import Enum
+from time import sleep
+
+try:
+    from time import monotonic
+except:
+    from .missing import monotonic
+
+csum_func = crcmod.predefined.mkCrcFun('xmodem')
+
+
+class RatpState(Enum):
+    listen = "listen"  # 1
+    syn_sent = "syn-sent"  # 2
+    syn_received = "syn-received"  # 3
+    established = "established"  # 4
+    fin_wait = "fin-wait"  # 5
+    last_ack = "last-ack"  # 6
+    closing = "closing"  # 7
+    time_wait = "time-wait"  # 8
+    closed = "closed"  # 9
+
+
+class RatpInvalidHeader(ValueError):
+    pass
+
+
+class RatpInvalidPayload(ValueError):
+    pass
+
+
+class RatpError(ValueError):
+    pass
+
+
+class RatpPacket(object):
+
+    def __init__(self, data=None, flags=''):
+        self.payload = None
+        self.synch = 0x01
+        self._control = 0
+        self.length = 0
+        self.csum = 0
+        self.c_syn = False
+        self.c_ack = False
+        self.c_fin = False
+        self.c_rst = False
+        self.c_sn = 0
+        self.c_an = 0
+        self.c_eor = False
+        self.c_so = False
+        if data:
+            (self.synch, self._control, self.length, self.csum) = \
+                struct.unpack('!BBBB', data)
+            if self.synch != 0x01:
+                raise RatpInvalidHeader("invalid synch octet (%x != %x)" %
+                                        (self.synch, 0x01))
+            csum = (self._control + self.length + self.csum) & 0xff
+            if csum != 0xff:
+                raise RatpInvalidHeader("invalid csum octet (%x != %x)" %
+                                        (csum, 0xff))
+            self._unpack_control()
+        elif flags:
+            if 'S' in flags:
+                self.c_syn = True
+            if 'A' in flags:
+                self.c_ack = True
+            if 'F' in flags:
+                self.c_fin = True
+            if 'R' in flags:
+                self.c_rst = True
+            if 'E' in flags:
+                self.c_eor = True
+
+    def __repr__(self):
+        s = "RatpPacket("
+        if self.c_syn:
+            s += "SYN,"
+        if self.c_ack:
+            s += "ACK,"
+        if self.c_fin:
+            s += "FIN,"
+        if self.c_rst:
+            s += "RST,"
+        s += "SN=%i,AN=%i," % (self.c_sn, self.c_an)
+        if self.c_eor:
+            s += "EOR,"
+        if self.c_so:
+            s += "SO,DATA=%i)" % self.length
+        else:
+            s += "DATA=%i)" % self.length
+        return s
+
+    def _pack_control(self):
+        self._control = 0 | \
+            self.c_syn << 7 | \
+            self.c_ack << 6 | \
+            self.c_fin << 5 | \
+            self.c_rst << 4 | \
+            self.c_sn << 3 | \
+            self.c_an << 2 | \
+            self.c_eor << 1 | \
+            self.c_so << 0
+
+    def _unpack_control(self):
+        self.c_syn = bool(self._control & 1 << 7)
+        self.c_ack = bool(self._control & 1 << 6)
+        self.c_fin = bool(self._control & 1 << 5)
+        self.c_rst = bool(self._control & 1 << 4)
+        self.c_sn = bool(self._control & 1 << 3)
+        self.c_an = bool(self._control & 1 << 2)
+        self.c_eor = bool(self._control & 1 << 1)
+        self.c_so = bool(self._control & 1 << 0)
+
+    def pack(self):
+        self._pack_control()
+        self.csum = 0
+        self.csum = (self._control + self.length + self.csum)
+        self.csum = (self.csum & 0xff) ^ 0xff
+        return struct.pack('!BBBB', self.synch, self._control, self.length,
+                           self.csum)
+
+    def unpack_payload(self, payload):
+        (c_recv,) = struct.unpack('!H', payload[-2:])
+        c_calc = csum_func(payload[:-2])
+        if c_recv != c_calc:
+            raise RatpInvalidPayload("bad checksum (%04x != %04x)" %
+                                     (c_recv, c_calc))
+        self.payload = payload[:-2]
+
+    def pack_payload(self):
+        c_calc = csum_func(self.payload)
+        return self.payload+struct.pack('!H', c_calc)
+
+
+class RatpConnection(object):
+    def __init__(self):
+        self._state = RatpState.closed
+        self._passive = True
+        self._input = b''
+        self._s_sn = 0
+        self._r_sn = 0
+        self._retrans = None
+        self._retrans_counter = None
+        self._retrans_deadline = None
+        self._r_mdl = None
+        self._s_mdl = 0xff
+        self._rx_buf = [] # reassembly buffer
+        self._rx_queue = []
+        self._tx_queue = []
+        self._rtt_alpha = 0.8
+        self._rtt_beta = 2.0
+        self._srtt = 0.2
+        self._rto_min, self._rto_max = 0.2, 1
+        self._tx_timestamp = None
+        self.total_retransmits = 0
+        self.total_crc_errors = 0
+
+    def _update_srtt(self, rtt):
+        self._srtt = (self._rtt_alpha * self._srtt) + \
+                     ((1.0 - self._rtt_alpha) * rtt)
+        logging.info("SRTT: %r", self._srtt)
+
+    def _get_rto(self):
+        return min(self._rto_max,
+                   max(self._rto_min, self._rtt_beta * self._srtt))
+
+    def _write(self, pkt):
+
+        if pkt.payload or pkt.c_so or pkt.c_syn or pkt.c_rst or pkt.c_fin:
+            self._s_sn = pkt.c_sn
+            if not self._retrans:
+                self._retrans = pkt
+                self._retrans_counter = 0
+            else:
+                self.total_retransmits += 1
+                self._retrans_counter += 1
+                if self._retrans_counter > 10:
+                    raise RatpError("Maximum retransmit count exceeded")
+            self._retrans_deadline = monotonic()+self._get_rto()
+
+        logging.info("Write: %r", pkt)
+
+        self._write_raw(pkt.pack())
+        if pkt.payload:
+            self._write_raw(pkt.pack_payload())
+        self._tx_timestamp = monotonic()
+
+    def _check_rto(self):
+        if self._retrans is None:
+            return
+
+        if self._retrans_deadline < monotonic():
+            logging.debug("Retransmit...")
+            self._write(self._retrans)
+
+    def _check_time_wait(self):
+        if not self._state == RatpState.time_wait:
+            return
+
+        remaining = self._time_wait_deadline - monotonic()
+        if remaining < 0:
+            self._state = RatpState.closed
+        else:
+            logging.debug("Time-Wait: %.2f remaining" % remaining)
+            sleep(min(remaining, 0.1))
+
+    def _read(self):
+        if len(self._input) < 4:
+            self._input += self._read_raw(4-len(self._input))
+        if len(self._input) < 4:
+            return
+
+        try:
+            pkt = RatpPacket(data=self._input[:4])
+        except RatpInvalidHeader as e:
+            logging.info("%r", e)
+            self._input = self._input[1:]
+            return
+
+        self._input = self._input[4:]
+
+        logging.info("Read: %r", pkt)
+
+        if pkt.c_syn or pkt.c_rst or pkt.c_so or pkt.c_fin:
+            return pkt
+
+        if pkt.length == 0:
+            return pkt
+
+        while len(self._input) < pkt.length+2:
+            self._input += self._read_raw()
+
+        try:
+            pkt.unpack_payload(self._input[:pkt.length+2])
+        except RatpInvalidPayload as e:
+            self.total_crc_errors += 1
+            return
+        finally:
+            self._input = self._input[pkt.length+2:]
+
+        return pkt
+
+    def _close(self):
+        pass
+
+    def _a(self, r):
+        logging.info("A")
+
+        if r.c_rst:
+            return True
+
+        if r.c_ack:
+            s = RatpPacket(flags='R')
+            s.c_sn = r.c_an
+            self._write(s)
+            return False
+
+        if r.c_syn:
+            self._r_mdl = r.length
+
+            s = RatpPacket(flags='SA')
+            s.c_sn = 0
+            s.c_an = (r.c_sn + 1) % 2
+            s.length = self._s_mdl
+            self._write(s)
+            self._state = RatpState.syn_received
+            return False
+
+        return False
+
+    def _b(self, r):
+        logging.info("B")
+
+        if r.c_ack and r.c_an != (self._s_sn + 1) % 2:
+            if r.c_rst:
+                return False
+            else:
+                s = RatpPacket(flags='R')
+                s.c_sn = r.c_an
+                self._write(s)
+                return False
+
+        if r.c_rst:
+            if r.c_ack:
+                self._retrans = None
+                # FIXME: delete the TCB
+                self._state = RatpState.closed
+                return False
+            else:
+                return False
+
+        if r.c_syn:
+            if r.c_ack:
+                self._r_mdl = r.length
+                self._retrans = None
+                self._r_sn = r.c_sn
+                s = RatpPacket(flags='A')
+                s.c_sn = r.c_an
+                s.c_an = (r.c_sn + 1) % 2
+                self._write(s)
+                self._state = RatpState.established
+                return False
+            else:
+                self._retrans = None
+                s = RatpPacket(flags='SA')
+                s.c_sn = 0
+                s.c_an = (r.c_sn + 1) % 2
+                s.length = self._s_mdl
+                self._write(s)
+                self._state = RatpState.syn_received
+                return False
+
+        return False
+
+    def _c1(self, r):
+        logging.info("C1")
+
+        if r.c_sn != self._r_sn:
+            return True
+
+        if r.c_rst or r.c_fin:
+            return False
+
+        s = RatpPacket(flags='A')
+        s.c_sn = r.c_an
+        s.c_an = (r.c_sn + 1) % 2
+        self._write(s)
+        return False
+
+    def _c2(self, r):
+        logging.info("C2")
+
+        if r.length == 0 and r.c_so == 0:
+            return True
+
+        if r.c_sn != self._r_sn:
+            return True
+
+        if r.c_rst or r.c_fin:
+            return False
+
+        if r.c_syn:
+            s = RatpPacket(flags='RA')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+            self._retrans = None
+            # FIXME: inform the user "Error: Connection reset"
+            self._state = RatpState.closed
+            return False
+
+        # FIXME: only ack duplicate data packages?
+        # This is not documented in RFC 916
+        if r.length or r.c_so:
+            logging.info("C2: duplicate data packet, dropping")
+            s = RatpPacket(flags='A')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+
+        return False
+
+    def _d1(self, r):
+        logging.info("D1")
+
+        if not r.c_rst:
+            return True
+
+        if self._passive:
+            self._retrans = None
+            self._state = RatpState.listen
+            return False
+        else:
+            self._retrans = None
+
+            self._state = RatpState.closed
+            raise RatpError("Connection refused")
+
+    def _d2(self, r):
+        logging.info("D2")
+
+        if not r.c_rst:
+            return True
+
+        self._retrans = None
+
+        self._state = RatpState.closed
+
+        raise RatpError("Connection reset")
+
+    def _d3(self, r):
+        logging.info("C3")
+
+        if not r.c_rst:
+            return True
+
+        self._state = RatpState.closed
+        return False
+
+    def _e(self, r):
+        logging.info("E")
+
+        if not r.c_syn:
+            return True
+
+        self._retrans = None
+        s = RatpPacket(flags='R')
+        if r.c_ack:
+            s.c_sn = r.c_an
+        else:
+            s.c_sn = 0
+        self._write(s)
+        self._state = RatpState.closed
+        raise RatpError("Connection reset")
+
+    def _f1(self, r):
+        logging.info("F1")
+
+        if not r.c_ack:
+            return False
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            return True
+
+        if self._passive:
+            self._retrans = None
+            s = RatpPacket(flags='R')
+            s.c_sn = r.c_an
+            self._write(s)
+            self._state = RatpState.listen
+            return False
+        else:
+            self._retrans = None
+            s = RatpPacket(flags='R')
+            s.c_sn = r.c_an
+            self._write(s)
+            self._state = RatpState.closed
+            raise RatpError("Connection refused")
+
+    def _f2(self, r):
+        logging.info("F2")
+
+        if not r.c_ack:
+            return False
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            if self._retrans:
+                self._retrans = None
+                self._update_srtt(monotonic()-self._tx_timestamp)
+                # FIXME: inform the user with an "Ok" if a buffer has been
+                # entirely acknowledged.  Another packet containing data may
+                # now be sent.
+            return True
+
+        return True
+
+    def _f3(self, r):
+        logging.info("F3")
+
+        if not r.c_ack:
+            return False
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            return True
+
+        return True
+
+    def _g(self, r):
+        logging.info("G")
+
+        if not r.c_rst:
+            return False
+
+        self._retrans = None
+        if r.c_ack:
+            s = RatpPacket(flags='R')
+            s.c_sn = r.c_an
+            self._write(s)
+        else:
+            s = RatpPacket(flags='RA')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+
+        return False
+
+    def _h1(self, r):
+        logging.info("H1")
+
+        # FIXME: initial data?
+        self._state = RatpState.established
+        self._r_sn = r.c_sn
+
+        return False
+
+    def _h2(self, r):
+        logging.info("H2")
+
+        if not r.c_fin:
+            return True
+
+        if self._retrans is not None:
+            # FIXME: inform the user "Warning: Data left unsent.", "Connection closing."
+            self._retrans = None
+        s = RatpPacket(flags='FA')
+        s.c_sn = r.c_an
+        s.c_an = (r.c_sn + 1) % 2
+        self._write(s)
+        self._state = RatpState.last_ack
+        raise RatpError("Connection closed by remote")
+
+    def _h3(self, r):
+        logging.info("H3")
+
+        if not r.c_fin:
+            # Our fin was lost, rely on retransmission
+            return False
+
+        if r.length or r.c_so:
+            self._retrans = None
+            s = RatpPacket(flags='RA')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+            self._state = RatpState.closed
+            raise RatpError("Connection reset")
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            self._retrans = None
+            s = RatpPacket(flags='A')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+            self._time_wait_deadline = monotonic() + self._get_rto()
+            self._state = RatpState.time_wait
+            return False
+        else:
+            self._retrans = None
+            s = RatpPacket(flags='A')
+            s.c_sn = r.c_an
+            s.c_an = (r.c_sn + 1) % 2
+            self._write(s)
+            self._state = RatpState.closing
+            return False
+
+    def _h4(self, r):
+        logging.info("H4")
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            self._retrans = None
+            self._time_wait_deadline = monotonic() + self._get_rto()
+            self._state = RatpState.time_wait
+            return False
+
+        return False
+
+    def _h5(self, r):
+        logging.info("H5")
+
+        if r.c_an == (self._s_sn + 1) % 2:
+            self._time_wait_deadline = monotonic() + self._get_rto()
+            self._state = RatpState.time_wait
+            return False
+
+        return False
+
+    def _h6(self, r):
+        logging.info("H6")
+
+        if not r.c_ack:
+            return False
+
+        if not r.c_fin:
+            return False
+
+        self._retrans = None
+        s = RatpPacket(flags='A')
+        s.c_sn = r.c_an
+        s.c_an = (r.c_sn + 1) % 2
+        self._write(s)
+        self._time_wait_deadline = monotonic() + self._get_rto()
+        return False
+
+    def _i1(self, r):
+        logging.info("I1")
+
+        if r.c_so:
+            self._r_sn = r.c_sn
+            self._rx_buf.append(chr(r.length))
+        elif r.length:
+            self._r_sn = r.c_sn
+            self._rx_buf.append(r.payload)
+        else:
+            return False
+
+        # reassemble
+        if r.c_eor:
+            logging.info("Reassembling %i frames", len(self._rx_buf))
+            self._rx_queue.append(''.join(self._rx_buf))
+            self._rx_buf = []
+
+        s = RatpPacket(flags='A')
+        s.c_sn = r.c_an
+        s.c_an = (r.c_sn + 1) % 2
+        self._write(s)
+        return False
+
+    def _machine(self, pkt):
+        logging.info("State: %r", self._state)
+        if self._state == RatpState.listen:
+            self._a(pkt)
+        elif self._state == RatpState.syn_sent:
+            self._b(pkt)
+        elif self._state == RatpState.syn_received:
+            self._c1(pkt) and \
+                self._d1(pkt) and \
+                self._e(pkt) and \
+                self._f1(pkt) and \
+                self._h1(pkt)
+        elif self._state == RatpState.established:
+            self._c2(pkt) and \
+                self._d2(pkt) and \
+                self._e(pkt) and \
+                self._f2(pkt) and \
+                self._h2(pkt) and \
+                self._i1(pkt)
+        elif self._state == RatpState.fin_wait:
+            self._c2(pkt) and \
+                self._d2(pkt) and \
+                self._e(pkt) and \
+                self._f3(pkt) and \
+                self._h3(pkt)
+        elif self._state == RatpState.last_ack:
+            self._c2(pkt) and \
+                self._d3(pkt) and \
+                self._e(pkt) and \
+                self._f3(pkt) and \
+                self._h4(pkt)
+        elif self._state == RatpState.closing:
+            self._c2(pkt) and \
+                self._d3(pkt) and \
+                self._e(pkt) and \
+                self._f3(pkt) and \
+                self._h5(pkt)
+        elif self._state == RatpState.time_wait:
+            self._d3(pkt) and \
+                self._e(pkt) and \
+                self._f3(pkt) and \
+                self._h6(pkt)
+        elif self._state == RatpState.closed:
+            self._g(pkt)
+
+    def wait(self, deadline):
+        while deadline is None or deadline > monotonic():
+            pkt = self._read()
+            if pkt:
+                self._machine(pkt)
+            else:
+                self._check_rto()
+                self._check_time_wait()
+            if not self._retrans or self._rx_queue:
+                return
+
+    def wait1(self, deadline):
+        while deadline is None or deadline > monotonic():
+            pkt = self._read()
+            if pkt:
+                self._machine(pkt)
+            else:
+                self._check_rto()
+                self._check_time_wait()
+            if not self._retrans:
+                return
+
+    def listen(self):
+        logging.info("LISTEN")
+        self._state = RatpState.listen
+
+    def connect(self, timeout=5.0):
+        deadline = monotonic() + timeout
+        logging.info("CONNECT")
+        self._retrans = None
+        syn = RatpPacket(flags='S')
+        syn.length = self._s_mdl
+        self._write(syn)
+        self._state = RatpState.syn_sent
+        self.wait(deadline)
+
+    def send_one(self, data, eor=True, timeout=1.0):
+        deadline = monotonic() + timeout
+        logging.info("SEND_ONE (len=%i, eor=%r)", len(data), eor)
+        assert self._state == RatpState.established
+        assert self._retrans is None
+        snd = RatpPacket(flags='A')
+        snd.c_eor = eor
+        snd.c_sn = (self._s_sn + 1) % 2
+        snd.c_an = (self._r_sn + 1) % 2
+        snd.length = len(data)
+        snd.payload = data
+        self._write(snd)
+        self.wait1(deadline=None)
+
+    def send(self, data, timeout=1.0):
+        logging.info("SEND (len=%i)", len(data))
+        while len(data) > 255:
+            self.send_one(data[:255], eor=False, timeout=timeout)
+            data = data[255:]
+        self.send_one(data, eor=True, timeout=timeout)
+
+    def recv(self, timeout=1.0):
+        deadline = monotonic() + timeout
+
+        assert self._state == RatpState.established
+        if self._rx_queue:
+            return self._rx_queue.pop(0)
+        self.wait(deadline)
+        if self._rx_queue:
+            return self._rx_queue.pop(0)
+
+    def close(self, timeout=1.0):
+        deadline = monotonic() + timeout
+        logging.info("CLOSE")
+        if self._state == RatpState.established:
+            fin = RatpPacket(flags='FA')  # FIXME: only F?
+            fin.c_sn = (self._s_sn + 1) % 2
+            fin.c_an = (self._r_sn + 1) % 2
+            self._write(fin)
+            self._state = RatpState.fin_wait
+        while deadline > monotonic() and not self._state == RatpState.time_wait:
+            self.wait(deadline)
+        while self._state == RatpState.time_wait:
+            self.wait(None)
+        if self._state == RatpState.closed:
+            logging.info("CLOSE: success")
+        else:
+            logging.info("CLOSE: failure")
+
+
+    def abort(self):
+        logging.info("ABORT")
+
+    def status(self):
+        logging.info("STATUS")
+        return self._state
+
+
+class SerialRatpConnection(RatpConnection):
+    def __init__(self, port):
+        super(SerialRatpConnection, self).__init__()
+        self.__port = port
+        self.__port.timeout = 0.01
+        self.__port.writeTimeout = None
+        self.__port.flushInput()
+
+    def _write_raw(self, data):
+        if data:
+            logging.debug("-> %r", bytearray(data))
+        return self.__port.write(data)
+
+    def _read_raw(self, size=1):
+        data = self.__port.read(size)
+        if data:
+            logging.debug("<- %r", bytearray(data))
+        return data
diff --git a/scripts/remote/ratpfs.py b/scripts/remote/ratpfs.py
new file mode 100644
index 0000000000..91ca044540
--- /dev/null
+++ b/scripts/remote/ratpfs.py
@@ -0,0 +1,189 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+from __future__ import absolute_import, division, print_function
+
+import logging
+import os
+import stat
+import struct
+from enum import IntEnum
+
+from .messages import BBPacketFS, BBPacketFSReturn
+
+class RatpFSType(IntEnum):
+    invalid = 0
+    mount_call = 1
+    mount_return = 2
+    readdir_call = 3
+    readdir_return = 4
+    stat_call = 5
+    stat_return = 6
+    open_call = 7
+    open_return = 8
+    read_call = 9
+    read_return = 10
+    write_call = 11
+    write_return = 12
+    close_call = 13
+    close_return = 14
+    truncate_call = 15
+    truncate_return = 16
+
+
+class RatpFSError(ValueError):
+    pass
+
+
+class RatpFSPacket(object):
+    def __init__(self, type=RatpFSType.invalid, payload="", raw=None):
+        if raw is not None:
+            type, = struct.unpack('!B', raw[:1])
+            self.type = RatpFSType(type)
+            self.payload = raw[1:]
+        else:
+            self.type = type
+            self.payload = payload
+
+    def __repr__(self):
+        s = "%s(" % self.__class__.__name__
+        s += "TYPE=%i," % self.type
+        s += "PAYLOAD=%s)" % repr(self.payload)
+        return s
+
+    def pack(self):
+        return struct.pack('!B', int(self.type))+self.payload
+
+
+class RatpFSServer(object):
+    def __init__(self, path=None):
+        self.path = path
+        if path:
+            self.path = os.path.abspath(os.path.expanduser(path))
+        self.next_handle = 1  # 0 is invalid
+        self.files = {}
+        self.mounted = False
+        logging.info("exporting: %s", self.path)
+
+    def _alloc_handle(self):
+        handle = self.next_handle
+        self.next_handle += 1
+        return handle
+
+    def _resolve(self, path):
+        components = path.split('/')
+        components = [x for x in components if x and x != '..']
+        return os.path.join(self.path, *components)
+
+    def handle_stat(self, path):
+
+        try:
+            logging.info("path: %r", path)
+            path = self._resolve(path)
+            logging.info("path1: %r", path)
+            s = os.stat(path)
+        except OSError as e:
+            return struct.pack('!BI', 0, e.errno)
+        if stat.S_ISREG(s.st_mode):
+            return struct.pack('!BI', 1, s.st_size)
+        elif stat.S_ISDIR(s.st_mode):
+            return struct.pack('!BI', 2, s.st_size)
+        else:
+            return struct.pack('!BI', 0, 0)
+
+    def handle_open(self, params):
+        flags, = struct.unpack('!I', params[:4])
+        flags = flags & (os.O_RDONLY | os.O_WRONLY | os.O_RDWR | os.O_CREAT |
+                         os.O_TRUNC)
+        path = params[4:]
+        try:
+            f = os.open(self._resolve(path), flags, 0666)
+        except OSError as e:
+            return struct.pack('!II', 0, e.errno)
+        h = self._alloc_handle()
+        self.files[h] = f
+        size = os.lseek(f, 0, os.SEEK_END)
+        return struct.pack('!II', h, size)
+
+    def handle_read(self, params):
+        h, pos, size = struct.unpack('!III', params)
+        f = self.files[h]
+        os.lseek(f, pos, os.SEEK_SET)
+        size = min(size, 4096)
+        return os.read(f, size)
+
+    def handle_write(self, params):
+        h, pos = struct.unpack('!II', params[:8])
+        payload = params[8:]
+        f = self.files[h]
+        pos = os.lseek(f, pos, os.SEEK_SET)
+        assert os.write(f, payload) == len(payload)
+        return ""
+
+    def handle_readdir(self, path):
+        res = ""
+        for x in os.listdir(self._resolve(path)):
+            res += x+'\0'
+        return res
+
+    def handle_close(self, params):
+        h, = struct.unpack('!I', params[:4])
+        os.close(self.files.pop(h))
+        return ""
+
+    def handle_truncate(self, params):
+        h, size = struct.unpack('!II', params)
+        f = self.files[h]
+        os.ftruncate(f, size)
+        return ""
+
+    def handle(self, bbcall):
+        assert isinstance(bbcall, BBPacketFS)
+        logging.debug("bb-call: %s", bbcall)
+        fscall = RatpFSPacket(raw=bbcall.payload)
+        logging.info("fs-call: %s", fscall)
+
+        if not self.path:
+            logging.warning("no filesystem exported")
+            fsreturn = RatpFSPacket(type=RatpFSType.invalid)
+        elif fscall.type == RatpFSType.mount_call:
+            self.mounted = True
+            fsreturn = RatpFSPacket(type=RatpFSType.mount_return)
+        elif not self.mounted:
+            logging.warning("filesystem not mounted")
+            fsreturn = RatpFSPacket(type=RatpFSType.invalid)
+        elif fscall.type == RatpFSType.readdir_call:
+            payload = self.handle_readdir(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.readdir_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.stat_call:
+            payload = self.handle_stat(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.stat_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.open_call:
+            payload = self.handle_open(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.open_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.read_call:
+            payload = self.handle_read(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.read_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.write_call:
+            payload = self.handle_write(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.write_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.close_call:
+            payload = self.handle_close(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.close_return,
+                                    payload=payload)
+        elif fscall.type == RatpFSType.truncate_call:
+            payload = self.handle_truncate(fscall.payload)
+            fsreturn = RatpFSPacket(type=RatpFSType.truncate_return,
+                                    payload=payload)
+        else:
+            raise RatpFSError()
+
+        logging.info("fs-return: %s", fsreturn)
+        bbreturn = BBPacketFSReturn(payload=fsreturn.pack())
+        logging.debug("bb-return: %s", bbreturn)
+        return bbreturn
diff --git a/scripts/remote/threadstdio.py b/scripts/remote/threadstdio.py
new file mode 100644
index 0000000000..db249892ac
--- /dev/null
+++ b/scripts/remote/threadstdio.py
@@ -0,0 +1,47 @@
+#!/usr/bin/python2
+
+import os
+import sys
+import termios
+import atexit
+from threading import Thread
+from Queue import Queue, Empty
+
+class ConsoleInput(Thread):
+    def __init__(self, queue, exit='\x14'):
+        Thread.__init__(self)
+        self.daemon = True
+        self.q = queue
+        self._exit = exit
+        self.fd = sys.stdin.fileno()
+        old = termios.tcgetattr(self.fd)
+        new = termios.tcgetattr(self.fd)
+        new[3] = new[3] & ~termios.ICANON & ~termios.ECHO & ~termios.ISIG
+        new[6][termios.VMIN] = 1
+        new[6][termios.VTIME] = 0
+        termios.tcsetattr(self.fd, termios.TCSANOW, new)
+
+        def cleanup():
+            termios.tcsetattr(self.fd, termios.TCSAFLUSH, old)
+        atexit.register(cleanup)
+
+    def run(self):
+        while True:
+            c = os.read(self.fd, 1)
+            if c == self._exit:
+                self.q.put((self, None))
+                return
+            else:
+                self.q.put((self, c))
+
+if __name__ == "__main__":
+    q = Queue()
+    i = ConsoleInput(q)
+    i.start()
+    while True:
+        event = q.get(block=True)
+        src, c = event
+        if c == '\x04':
+            break
+        os.write(sys.stdout.fileno(), c.upper())
+
diff --git a/scripts/serial/__init__.py b/scripts/serial/__init__.py
new file mode 100644
index 0000000000..33ae52ec11
--- /dev/null
+++ b/scripts/serial/__init__.py
@@ -0,0 +1,79 @@
+#!/usr/bin/env python 
+
+# portable serial port access with python
+# this is a wrapper module for different platform implementations
+#
+# (C) 2001-2010 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+VERSION = '2.7'
+
+import sys
+
+if sys.platform == 'cli':
+    from serial.serialcli import *
+else:
+    import os
+    # chose an implementation, depending on os
+    if os.name == 'nt': #sys.platform == 'win32':
+        from serial.serialwin32 import *
+    elif os.name == 'posix':
+        from serial.serialposix import *
+    elif os.name == 'java':
+        from serial.serialjava import *
+    else:
+        raise ImportError("Sorry: no implementation for your platform ('%s') available" % (os.name,))
+
+
+protocol_handler_packages = [
+        'serial.urlhandler',
+        ]
+
+def serial_for_url(url, *args, **kwargs):
+    """\
+    Get an instance of the Serial class, depending on port/url. The port is not
+    opened when the keyword parameter 'do_not_open' is true, by default it
+    is. All other parameters are directly passed to the __init__ method when
+    the port is instantiated.
+
+    The list of package names that is searched for protocol handlers is kept in
+    ``protocol_handler_packages``.
+
+    e.g. we want to support a URL ``foobar://``. A module
+    ``my_handlers.protocol_foobar`` is provided by the user. Then
+    ``protocol_handler_packages.append("my_handlers")`` would extend the search
+    path so that ``serial_for_url("foobar://"))`` would work.
+    """
+    # check remove extra parameter to not confuse the Serial class
+    do_open = 'do_not_open' not in kwargs or not kwargs['do_not_open']
+    if 'do_not_open' in kwargs: del kwargs['do_not_open']
+    # the default is to use the native version
+    klass = Serial   # 'native' implementation
+    # check port type and get class
+    try:
+        url_nocase = url.lower()
+    except AttributeError:
+        # it's not a string, use default
+        pass
+    else:
+        if '://' in url_nocase:
+            protocol = url_nocase.split('://', 1)[0]
+            for package_name in protocol_handler_packages:
+                module_name = '%s.protocol_%s' % (package_name, protocol,)
+                try:
+                    handler_module = __import__(module_name)
+                except ImportError:
+                    pass
+                else:
+                    klass = sys.modules[module_name].Serial
+                    break
+            else:
+                raise ValueError('invalid URL, protocol %r not known' % (protocol,))
+        else:
+            klass = Serial   # 'native' implementation
+    # instantiate and open when desired
+    instance = klass(None, *args, **kwargs)
+    instance.port = url
+    if do_open:
+        instance.open()
+    return instance
diff --git a/scripts/serial/rfc2217.py b/scripts/serial/rfc2217.py
new file mode 100644
index 0000000000..b65edd55c8
--- /dev/null
+++ b/scripts/serial/rfc2217.py
@@ -0,0 +1,1327 @@
+#! python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see __init__.py
+#
+# This module implements a RFC2217 compatible client. RF2217 descibes a
+# protocol to access serial ports over TCP/IP and allows setting the baud rate,
+# modem control lines etc.
+#
+# (C) 2001-2013 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+# TODO:
+# - setting control line -> answer is not checked (had problems with one of the
+#   severs). consider implementing a compatibility mode flag to make check
+#   conditional
+# - write timeout not implemented at all
+
+##############################################################################
+# observations and issues with servers
+#=============================================================================
+# sredird V2.2.1
+# - http://www.ibiblio.org/pub/Linux/system/serial/   sredird-2.2.2.tar.gz
+# - does not acknowledge SET_CONTROL (RTS/DTR) correctly, always responding
+#   [105 1] instead of the actual value.
+# - SET_BAUDRATE answer contains 4 extra null bytes -> probably for larger
+#   numbers than 2**32?
+# - To get the signature [COM_PORT_OPTION 0] has to be sent.
+# - run a server: while true; do nc -l -p 7000 -c "sredird debug /dev/ttyUSB0 /var/lock/sredir"; done
+#=============================================================================
+# telnetcpcd (untested)
+# - http://ftp.wayne.edu/kermit/sredird/telnetcpcd-1.09.tar.gz
+# - To get the signature [COM_PORT_OPTION] w/o data has to be sent.
+#=============================================================================
+# ser2net
+# - does not negotiate BINARY or COM_PORT_OPTION for his side but at least
+#   acknowledges that the client activates these options
+# - The configuration may be that the server prints a banner. As this client
+#   implementation does a flushInput on connect, this banner is hidden from
+#   the user application.
+# - NOTIFY_MODEMSTATE: the poll interval of the server seems to be one
+#   second.
+# - To get the signature [COM_PORT_OPTION 0] has to be sent.
+# - run a server: run ser2net daemon, in /etc/ser2net.conf:
+#     2000:telnet:0:/dev/ttyS0:9600 remctl banner
+##############################################################################
+
+# How to identify ports? pySerial might want to support other protocols in the
+# future, so lets use an URL scheme.
+# for RFC2217 compliant servers we will use this:
+#    rfc2217://<host>:<port>[/option[/option...]]
+#
+# options:
+# - "debug" print diagnostic messages
+# - "ign_set_control": do not look at the answers to SET_CONTROL
+# - "poll_modem": issue NOTIFY_MODEMSTATE requests when CTS/DTR/RI/CD is read.
+#   Without this option it expects that the server sends notifications
+#   automatically on change (which most servers do and is according to the
+#   RFC).
+# the order of the options is not relevant
+
+from serial.serialutil import *
+import time
+import struct
+import socket
+import threading
+import Queue
+import logging
+
+# port string is expected to be something like this:
+# rfc2217://host:port
+# host may be an IP or including domain, whatever.
+# port is 0...65535
+
+# map log level names to constants. used in fromURL()
+LOGGER_LEVELS = {
+    'debug': logging.DEBUG,
+    'info': logging.INFO,
+    'warning': logging.WARNING,
+    'error': logging.ERROR,
+    }
+
+
+# telnet protocol characters
+IAC  = to_bytes([255]) # Interpret As Command
+DONT = to_bytes([254])
+DO   = to_bytes([253])
+WONT = to_bytes([252])
+WILL = to_bytes([251])
+IAC_DOUBLED = to_bytes([IAC, IAC])
+
+SE  = to_bytes([240])  # Subnegotiation End
+NOP = to_bytes([241])  # No Operation
+DM  = to_bytes([242])  # Data Mark
+BRK = to_bytes([243])  # Break
+IP  = to_bytes([244])  # Interrupt process
+AO  = to_bytes([245])  # Abort output
+AYT = to_bytes([246])  # Are You There
+EC  = to_bytes([247])  # Erase Character
+EL  = to_bytes([248])  # Erase Line
+GA  = to_bytes([249])  # Go Ahead
+SB =  to_bytes([250])  # Subnegotiation Begin
+
+# selected telnet options
+BINARY = to_bytes([0]) # 8-bit data path
+ECHO = to_bytes([1])   # echo
+SGA = to_bytes([3])    # suppress go ahead
+
+# RFC2217
+COM_PORT_OPTION = to_bytes([44])
+
+# Client to Access Server
+SET_BAUDRATE = to_bytes([1])
+SET_DATASIZE = to_bytes([2])
+SET_PARITY = to_bytes([3])
+SET_STOPSIZE = to_bytes([4])
+SET_CONTROL = to_bytes([5])
+NOTIFY_LINESTATE = to_bytes([6])
+NOTIFY_MODEMSTATE = to_bytes([7])
+FLOWCONTROL_SUSPEND = to_bytes([8])
+FLOWCONTROL_RESUME = to_bytes([9])
+SET_LINESTATE_MASK = to_bytes([10])
+SET_MODEMSTATE_MASK = to_bytes([11])
+PURGE_DATA = to_bytes([12])
+
+SERVER_SET_BAUDRATE = to_bytes([101])
+SERVER_SET_DATASIZE = to_bytes([102])
+SERVER_SET_PARITY = to_bytes([103])
+SERVER_SET_STOPSIZE = to_bytes([104])
+SERVER_SET_CONTROL = to_bytes([105])
+SERVER_NOTIFY_LINESTATE = to_bytes([106])
+SERVER_NOTIFY_MODEMSTATE = to_bytes([107])
+SERVER_FLOWCONTROL_SUSPEND = to_bytes([108])
+SERVER_FLOWCONTROL_RESUME = to_bytes([109])
+SERVER_SET_LINESTATE_MASK = to_bytes([110])
+SERVER_SET_MODEMSTATE_MASK = to_bytes([111])
+SERVER_PURGE_DATA = to_bytes([112])
+
+RFC2217_ANSWER_MAP = {
+    SET_BAUDRATE: SERVER_SET_BAUDRATE,
+    SET_DATASIZE: SERVER_SET_DATASIZE,
+    SET_PARITY: SERVER_SET_PARITY,
+    SET_STOPSIZE: SERVER_SET_STOPSIZE,
+    SET_CONTROL: SERVER_SET_CONTROL,
+    NOTIFY_LINESTATE: SERVER_NOTIFY_LINESTATE,
+    NOTIFY_MODEMSTATE: SERVER_NOTIFY_MODEMSTATE,
+    FLOWCONTROL_SUSPEND: SERVER_FLOWCONTROL_SUSPEND,
+    FLOWCONTROL_RESUME: SERVER_FLOWCONTROL_RESUME,
+    SET_LINESTATE_MASK: SERVER_SET_LINESTATE_MASK,
+    SET_MODEMSTATE_MASK: SERVER_SET_MODEMSTATE_MASK,
+    PURGE_DATA: SERVER_PURGE_DATA,
+}
+
+SET_CONTROL_REQ_FLOW_SETTING = to_bytes([0])        # Request Com Port Flow Control Setting (outbound/both)
+SET_CONTROL_USE_NO_FLOW_CONTROL = to_bytes([1])     # Use No Flow Control (outbound/both)
+SET_CONTROL_USE_SW_FLOW_CONTROL = to_bytes([2])     # Use XON/XOFF Flow Control (outbound/both)
+SET_CONTROL_USE_HW_FLOW_CONTROL = to_bytes([3])     # Use HARDWARE Flow Control (outbound/both)
+SET_CONTROL_REQ_BREAK_STATE = to_bytes([4])         # Request BREAK State
+SET_CONTROL_BREAK_ON = to_bytes([5])                # Set BREAK State ON
+SET_CONTROL_BREAK_OFF = to_bytes([6])               # Set BREAK State OFF
+SET_CONTROL_REQ_DTR = to_bytes([7])                 # Request DTR Signal State
+SET_CONTROL_DTR_ON = to_bytes([8])                  # Set DTR Signal State ON
+SET_CONTROL_DTR_OFF = to_bytes([9])                 # Set DTR Signal State OFF
+SET_CONTROL_REQ_RTS = to_bytes([10])                # Request RTS Signal State
+SET_CONTROL_RTS_ON = to_bytes([11])                 # Set RTS Signal State ON
+SET_CONTROL_RTS_OFF = to_bytes([12])                # Set RTS Signal State OFF
+SET_CONTROL_REQ_FLOW_SETTING_IN = to_bytes([13])    # Request Com Port Flow Control Setting (inbound)
+SET_CONTROL_USE_NO_FLOW_CONTROL_IN = to_bytes([14]) # Use No Flow Control (inbound)
+SET_CONTROL_USE_SW_FLOW_CONTOL_IN = to_bytes([15])  # Use XON/XOFF Flow Control (inbound)
+SET_CONTROL_USE_HW_FLOW_CONTOL_IN = to_bytes([16])  # Use HARDWARE Flow Control (inbound)
+SET_CONTROL_USE_DCD_FLOW_CONTROL = to_bytes([17])   # Use DCD Flow Control (outbound/both)
+SET_CONTROL_USE_DTR_FLOW_CONTROL = to_bytes([18])   # Use DTR Flow Control (inbound)
+SET_CONTROL_USE_DSR_FLOW_CONTROL = to_bytes([19])   # Use DSR Flow Control (outbound/both)
+
+LINESTATE_MASK_TIMEOUT = 128                # Time-out Error
+LINESTATE_MASK_SHIFTREG_EMPTY = 64          # Transfer Shift Register Empty
+LINESTATE_MASK_TRANSREG_EMPTY = 32          # Transfer Holding Register Empty
+LINESTATE_MASK_BREAK_DETECT = 16            # Break-detect Error
+LINESTATE_MASK_FRAMING_ERROR = 8            # Framing Error
+LINESTATE_MASK_PARTIY_ERROR = 4             # Parity Error
+LINESTATE_MASK_OVERRUN_ERROR = 2            # Overrun Error
+LINESTATE_MASK_DATA_READY = 1               # Data Ready
+
+MODEMSTATE_MASK_CD = 128                    # Receive Line Signal Detect (also known as Carrier Detect)
+MODEMSTATE_MASK_RI = 64                     # Ring Indicator
+MODEMSTATE_MASK_DSR = 32                    # Data-Set-Ready Signal State
+MODEMSTATE_MASK_CTS = 16                    # Clear-To-Send Signal State
+MODEMSTATE_MASK_CD_CHANGE = 8               # Delta Receive Line Signal Detect
+MODEMSTATE_MASK_RI_CHANGE = 4               # Trailing-edge Ring Detector
+MODEMSTATE_MASK_DSR_CHANGE = 2              # Delta Data-Set-Ready
+MODEMSTATE_MASK_CTS_CHANGE = 1              # Delta Clear-To-Send
+
+PURGE_RECEIVE_BUFFER = to_bytes([1])        # Purge access server receive data buffer
+PURGE_TRANSMIT_BUFFER = to_bytes([2])       # Purge access server transmit data buffer
+PURGE_BOTH_BUFFERS = to_bytes([3])          # Purge both the access server receive data buffer and the access server transmit data buffer
+
+
+RFC2217_PARITY_MAP = {
+    PARITY_NONE: 1,
+    PARITY_ODD: 2,
+    PARITY_EVEN: 3,
+    PARITY_MARK: 4,
+    PARITY_SPACE: 5,
+}
+RFC2217_REVERSE_PARITY_MAP = dict((v,k) for k,v in RFC2217_PARITY_MAP.items())
+
+RFC2217_STOPBIT_MAP = {
+    STOPBITS_ONE: 1,
+    STOPBITS_ONE_POINT_FIVE: 3,
+    STOPBITS_TWO: 2,
+}
+RFC2217_REVERSE_STOPBIT_MAP = dict((v,k) for k,v in RFC2217_STOPBIT_MAP.items())
+
+# Telnet filter states
+M_NORMAL = 0
+M_IAC_SEEN = 1
+M_NEGOTIATE = 2
+
+# TelnetOption and TelnetSubnegotiation states
+REQUESTED = 'REQUESTED'
+ACTIVE = 'ACTIVE'
+INACTIVE = 'INACTIVE'
+REALLY_INACTIVE = 'REALLY_INACTIVE'
+
+class TelnetOption(object):
+    """Manage a single telnet option, keeps track of DO/DONT WILL/WONT."""
+
+    def __init__(self, connection, name, option, send_yes, send_no, ack_yes, ack_no, initial_state, activation_callback=None):
+        """\
+        Initialize option.
+        :param connection: connection used to transmit answers
+        :param name: a readable name for debug outputs
+        :param send_yes: what to send when option is to be enabled.
+        :param send_no: what to send when option is to be disabled.
+        :param ack_yes: what to expect when remote agrees on option.
+        :param ack_no: what to expect when remote disagrees on option.
+        :param initial_state: options initialized with REQUESTED are tried to
+            be enabled on startup. use INACTIVE for all others.
+        """
+        self.connection = connection
+        self.name = name
+        self.option = option
+        self.send_yes = send_yes
+        self.send_no = send_no
+        self.ack_yes = ack_yes
+        self.ack_no = ack_no
+        self.state = initial_state
+        self.active = False
+        self.activation_callback = activation_callback
+
+    def __repr__(self):
+        """String for debug outputs"""
+        return "%s:%s(%s)" % (self.name, self.active, self.state)
+
+    def process_incoming(self, command):
+        """\
+        A DO/DONT/WILL/WONT was received for this option, update state and
+        answer when needed.
+        """
+        if command == self.ack_yes:
+            if self.state is REQUESTED:
+                self.state = ACTIVE
+                self.active = True
+                if self.activation_callback is not None:
+                    self.activation_callback()
+            elif self.state is ACTIVE:
+                pass
+            elif self.state is INACTIVE:
+                self.state = ACTIVE
+                self.connection.telnetSendOption(self.send_yes, self.option)
+                self.active = True
+                if self.activation_callback is not None:
+                    self.activation_callback()
+            elif self.state is REALLY_INACTIVE:
+                self.connection.telnetSendOption(self.send_no, self.option)
+            else:
+                raise ValueError('option in illegal state %r' % self)
+        elif command == self.ack_no:
+            if self.state is REQUESTED:
+                self.state = INACTIVE
+                self.active = False
+            elif self.state is ACTIVE:
+                self.state = INACTIVE
+                self.connection.telnetSendOption(self.send_no, self.option)
+                self.active = False
+            elif self.state is INACTIVE:
+                pass
+            elif self.state is REALLY_INACTIVE:
+                pass
+            else:
+                raise ValueError('option in illegal state %r' % self)
+
+
+class TelnetSubnegotiation(object):
+    """\
+    A object to handle subnegotiation of options. In this case actually
+    sub-sub options for RFC 2217. It is used to track com port options.
+    """
+
+    def __init__(self, connection, name, option, ack_option=None):
+        if ack_option is None: ack_option = option
+        self.connection = connection
+        self.name = name
+        self.option = option
+        self.value = None
+        self.ack_option = ack_option
+        self.state = INACTIVE
+
+    def __repr__(self):
+        """String for debug outputs."""
+        return "%s:%s" % (self.name, self.state)
+
+    def set(self, value):
+        """\
+        Request a change of the value. a request is sent to the server. if
+        the client needs to know if the change is performed he has to check the
+        state of this object.
+        """
+        self.value = value
+        self.state = REQUESTED
+        self.connection.rfc2217SendSubnegotiation(self.option, self.value)
+        if self.connection.logger:
+            self.connection.logger.debug("SB Requesting %s -> %r" % (self.name, self.value))
+
+    def isReady(self):
+        """\
+        Check if answer from server has been received. when server rejects
+        the change, raise a ValueError.
+        """
+        if self.state == REALLY_INACTIVE:
+            raise ValueError("remote rejected value for option %r" % (self.name))
+        return self.state == ACTIVE
+    # add property to have a similar interface as TelnetOption
+    active = property(isReady)
+
+    def wait(self, timeout=3):
+        """\
+        Wait until the subnegotiation has been acknowledged or timeout. It
+        can also throw a value error when the answer from the server does not
+        match the value sent.
+        """
+        timeout_time = time.time() + timeout
+        while time.time() < timeout_time:
+            if self.isReady():
+                break
+            time.sleep(0.001)    # prevent 100% CPU load
+        else:
+            raise SerialException("timeout while waiting for option %r" % (self.name))
+
+    def checkAnswer(self, suboption):
+        """\
+        Check an incoming subnegotiation block. The parameter already has
+        cut off the header like sub option number and com port option value.
+        """
+        if self.value == suboption[:len(self.value)]:
+            self.state = ACTIVE
+        else:
+            # error propagation done in isReady
+            self.state = REALLY_INACTIVE
+        if self.connection.logger:
+            self.connection.logger.debug("SB Answer %s -> %r -> %s" % (self.name, suboption, self.state))
+
+
+class RFC2217Serial(SerialBase):
+    """Serial port implementation for RFC 2217 remote serial ports."""
+
+    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+                 9600, 19200, 38400, 57600, 115200)
+
+    def open(self):
+        """\
+        Open port with current settings. This may throw a SerialException
+        if the port cannot be opened.
+        """
+        self.logger = None
+        self._ignore_set_control_answer = False
+        self._poll_modem_state = False
+        self._network_timeout = 3
+        if self._port is None:
+            raise SerialException("Port must be configured before it can be used.")
+        if self._isOpen:
+            raise SerialException("Port is already open.")
+        try:
+            self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            self._socket.connect(self.fromURL(self.portstr))
+            self._socket.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1)
+        except Exception, msg:
+            self._socket = None
+            raise SerialException("Could not open port %s: %s" % (self.portstr, msg))
+
+        self._socket.settimeout(5) # XXX good value?
+
+        # use a thread save queue as buffer. it also simplifies implementing
+        # the read timeout
+        self._read_buffer = Queue.Queue()
+        # to ensure that user writes does not interfere with internal
+        # telnet/rfc2217 options establish a lock
+        self._write_lock = threading.Lock()
+        # name the following separately so that, below, a check can be easily done
+        mandadory_options = [
+            TelnetOption(self, 'we-BINARY', BINARY, WILL, WONT, DO, DONT, INACTIVE),
+            TelnetOption(self, 'we-RFC2217', COM_PORT_OPTION, WILL, WONT, DO, DONT, REQUESTED),
+        ]
+        # all supported telnet options
+        self._telnet_options = [
+            TelnetOption(self, 'ECHO', ECHO, DO, DONT, WILL, WONT, REQUESTED),
+            TelnetOption(self, 'we-SGA', SGA, WILL, WONT, DO, DONT, REQUESTED),
+            TelnetOption(self, 'they-SGA', SGA, DO, DONT, WILL, WONT, REQUESTED),
+            TelnetOption(self, 'they-BINARY', BINARY, DO, DONT, WILL, WONT, INACTIVE),
+            TelnetOption(self, 'they-RFC2217', COM_PORT_OPTION, DO, DONT, WILL, WONT, REQUESTED),
+        ] + mandadory_options
+        # RFC 2217 specific states
+        # COM port settings
+        self._rfc2217_port_settings = {
+            'baudrate': TelnetSubnegotiation(self, 'baudrate', SET_BAUDRATE, SERVER_SET_BAUDRATE),
+            'datasize': TelnetSubnegotiation(self, 'datasize', SET_DATASIZE, SERVER_SET_DATASIZE),
+            'parity':   TelnetSubnegotiation(self, 'parity',   SET_PARITY,   SERVER_SET_PARITY),
+            'stopsize': TelnetSubnegotiation(self, 'stopsize', SET_STOPSIZE, SERVER_SET_STOPSIZE),
+            }
+        # There are more subnegotiation objects, combine all in one dictionary
+        # for easy access
+        self._rfc2217_options = {
+            'purge':    TelnetSubnegotiation(self, 'purge',    PURGE_DATA,   SERVER_PURGE_DATA),
+            'control':  TelnetSubnegotiation(self, 'control',  SET_CONTROL,  SERVER_SET_CONTROL),
+            }
+        self._rfc2217_options.update(self._rfc2217_port_settings)
+        # cache for line and modem states that the server sends to us
+        self._linestate = 0
+        self._modemstate = None
+        self._modemstate_expires = 0
+        # RFC 2217 flow control between server and client
+        self._remote_suspend_flow = False
+
+        self._thread = threading.Thread(target=self._telnetReadLoop)
+        self._thread.setDaemon(True)
+        self._thread.setName('pySerial RFC 2217 reader thread for %s' % (self._port,))
+        self._thread.start()
+
+        # negotiate Telnet/RFC 2217 -> send initial requests
+        for option in self._telnet_options:
+            if option.state is REQUESTED:
+                self.telnetSendOption(option.send_yes, option.option)
+        # now wait until important options are negotiated
+        timeout_time = time.time() + self._network_timeout
+        while time.time() < timeout_time:
+            if sum(o.active for o in mandadory_options) == sum(o.state != INACTIVE for o in mandadory_options):
+                break
+            time.sleep(0.001)    # prevent 100% CPU load
+        else:
+            raise SerialException("Remote does not seem to support RFC2217 or BINARY mode %r" % mandadory_options)
+        if self.logger:
+            self.logger.info("Negotiated options: %s" % self._telnet_options)
+
+        # fine, go on, set RFC 2271 specific things
+        self._reconfigurePort()
+        # all things set up get, now a clean start
+        self._isOpen = True
+        if not self._rtscts:
+            self.setRTS(True)
+            self.setDTR(True)
+        self.flushInput()
+        self.flushOutput()
+
+    def _reconfigurePort(self):
+        """Set communication parameters on opened port."""
+        if self._socket is None:
+            raise SerialException("Can only operate on open ports")
+
+        # if self._timeout != 0 and self._interCharTimeout is not None:
+            # XXX
+
+        if self._writeTimeout is not None:
+            raise NotImplementedError('writeTimeout is currently not supported')
+            # XXX
+
+        # Setup the connection
+        # to get good performance, all parameter changes are sent first...
+        if not isinstance(self._baudrate, (int, long)) or not 0 < self._baudrate < 2**32:
+            raise ValueError("invalid baudrate: %r" % (self._baudrate))
+        self._rfc2217_port_settings['baudrate'].set(struct.pack('!I', self._baudrate))
+        self._rfc2217_port_settings['datasize'].set(struct.pack('!B', self._bytesize))
+        self._rfc2217_port_settings['parity'].set(struct.pack('!B', RFC2217_PARITY_MAP[self._parity]))
+        self._rfc2217_port_settings['stopsize'].set(struct.pack('!B', RFC2217_STOPBIT_MAP[self._stopbits]))
+
+        # and now wait until parameters are active
+        items = self._rfc2217_port_settings.values()
+        if self.logger:
+            self.logger.debug("Negotiating settings: %s" % (items,))
+        timeout_time = time.time() + self._network_timeout
+        while time.time() < timeout_time:
+            if sum(o.active for o in items) == len(items):
+                break
+            time.sleep(0.001)    # prevent 100% CPU load
+        else:
+            raise SerialException("Remote does not accept parameter change (RFC2217): %r" % items)
+        if self.logger:
+            self.logger.info("Negotiated settings: %s" % (items,))
+
+        if self._rtscts and self._xonxoff:
+            raise ValueError('xonxoff and rtscts together are not supported')
+        elif self._rtscts:
+            self.rfc2217SetControl(SET_CONTROL_USE_HW_FLOW_CONTROL)
+        elif self._xonxoff:
+            self.rfc2217SetControl(SET_CONTROL_USE_SW_FLOW_CONTROL)
+        else:
+            self.rfc2217SetControl(SET_CONTROL_USE_NO_FLOW_CONTROL)
+
+    def close(self):
+        """Close port"""
+        if self._isOpen:
+            if self._socket:
+                try:
+                    self._socket.shutdown(socket.SHUT_RDWR)
+                    self._socket.close()
+                except:
+                    # ignore errors.
+                    pass
+                self._socket = None
+            if self._thread:
+                self._thread.join()
+            self._isOpen = False
+            # in case of quick reconnects, give the server some time
+            time.sleep(0.3)
+
+    def makeDeviceName(self, port):
+        raise SerialException("there is no sensible way to turn numbers into URLs")
+
+    def fromURL(self, url):
+        """extract host and port from an URL string"""
+        if url.lower().startswith("rfc2217://"): url = url[10:]
+        try:
+            # is there a "path" (our options)?
+            if '/' in url:
+                # cut away options
+                url, options = url.split('/', 1)
+                # process options now, directly altering self
+                for option in options.split('/'):
+                    if '=' in option:
+                        option, value = option.split('=', 1)
+                    else:
+                        value = None
+                    if option == 'logging':
+                        logging.basicConfig()   # XXX is that good to call it here?
+                        self.logger = logging.getLogger('pySerial.rfc2217')
+                        self.logger.setLevel(LOGGER_LEVELS[value])
+                        self.logger.debug('enabled logging')
+                    elif option == 'ign_set_control':
+                        self._ignore_set_control_answer = True
+                    elif option == 'poll_modem':
+                        self._poll_modem_state = True
+                    elif option == 'timeout':
+                        self._network_timeout = float(value)
+                    else:
+                        raise ValueError('unknown option: %r' % (option,))
+            # get host and port
+            host, port = url.split(':', 1) # may raise ValueError because of unpacking
+            port = int(port)               # and this if it's not a number
+            if not 0 <= port < 65536: raise ValueError("port not in range 0...65535")
+        except ValueError, e:
+            raise SerialException('expected a string in the form "[rfc2217://]<host>:<port>[/option[/option...]]": %s' % e)
+        return (host, port)
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def inWaiting(self):
+        """Return the number of characters currently in the input buffer."""
+        if not self._isOpen: raise portNotOpenError
+        return self._read_buffer.qsize()
+
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if not self._isOpen: raise portNotOpenError
+        data = bytearray()
+        try:
+            while len(data) < size:
+                if self._thread is None:
+                    raise SerialException('connection failed (reader thread died)')
+                data.append(self._read_buffer.get(True, self._timeout))
+        except Queue.Empty: # -> timeout
+            pass
+        return bytes(data)
+
+    def write(self, data):
+        """\
+        Output the given string over the serial port. Can block if the
+        connection is blocked. May raise SerialException if the connection is
+        closed.
+        """
+        if not self._isOpen: raise portNotOpenError
+        self._write_lock.acquire()
+        try:
+            try:
+                self._socket.sendall(to_bytes(data).replace(IAC, IAC_DOUBLED))
+            except socket.error, e:
+                raise SerialException("connection failed (socket error): %s" % e) # XXX what exception if socket connection fails
+        finally:
+            self._write_lock.release()
+        return len(data)
+
+    def flushInput(self):
+        """Clear input buffer, discarding all that is in the buffer."""
+        if not self._isOpen: raise portNotOpenError
+        self.rfc2217SendPurge(PURGE_RECEIVE_BUFFER)
+        # empty read buffer
+        while self._read_buffer.qsize():
+            self._read_buffer.get(False)
+
+    def flushOutput(self):
+        """\
+        Clear output buffer, aborting the current output and
+        discarding all that is in the buffer.
+        """
+        if not self._isOpen: raise portNotOpenError
+        self.rfc2217SendPurge(PURGE_TRANSMIT_BUFFER)
+
+    def sendBreak(self, duration=0.25):
+        """\
+        Send break condition. Timed, returns to idle state after given
+        duration.
+        """
+        if not self._isOpen: raise portNotOpenError
+        self.setBreak(True)
+        time.sleep(duration)
+        self.setBreak(False)
+
+    def setBreak(self, level=True):
+        """\
+        Set break: Controls TXD. When active, to transmitting is
+        possible.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('set BREAK to %s' % ('inactive', 'active')[bool(level)])
+        if level:
+            self.rfc2217SetControl(SET_CONTROL_BREAK_ON)
+        else:
+            self.rfc2217SetControl(SET_CONTROL_BREAK_OFF)
+
+    def setRTS(self, level=True):
+        """Set terminal status line: Request To Send."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('set RTS to %s' % ('inactive', 'active')[bool(level)])
+        if level:
+            self.rfc2217SetControl(SET_CONTROL_RTS_ON)
+        else:
+            self.rfc2217SetControl(SET_CONTROL_RTS_OFF)
+
+    def setDTR(self, level=True):
+        """Set terminal status line: Data Terminal Ready."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('set DTR to %s' % ('inactive', 'active')[bool(level)])
+        if level:
+            self.rfc2217SetControl(SET_CONTROL_DTR_ON)
+        else:
+            self.rfc2217SetControl(SET_CONTROL_DTR_OFF)
+
+    def getCTS(self):
+        """Read terminal status line: Clear To Send."""
+        if not self._isOpen: raise portNotOpenError
+        return bool(self.getModemState() & MODEMSTATE_MASK_CTS)
+
+    def getDSR(self):
+        """Read terminal status line: Data Set Ready."""
+        if not self._isOpen: raise portNotOpenError
+        return bool(self.getModemState() & MODEMSTATE_MASK_DSR)
+
+    def getRI(self):
+        """Read terminal status line: Ring Indicator."""
+        if not self._isOpen: raise portNotOpenError
+        return bool(self.getModemState() & MODEMSTATE_MASK_RI)
+
+    def getCD(self):
+        """Read terminal status line: Carrier Detect."""
+        if not self._isOpen: raise portNotOpenError
+        return bool(self.getModemState() & MODEMSTATE_MASK_CD)
+
+    # - - - platform specific - - -
+    # None so far
+
+    # - - - RFC2217 specific - - -
+
+    def _telnetReadLoop(self):
+        """Read loop for the socket."""
+        mode = M_NORMAL
+        suboption = None
+        try:
+            while self._socket is not None:
+                try:
+                    data = self._socket.recv(1024)
+                except socket.timeout:
+                    # just need to get out of recv form time to time to check if
+                    # still alive
+                    continue
+                except socket.error, e:
+                    # connection fails -> terminate loop
+                    if self.logger:
+                        self.logger.debug("socket error in reader thread: %s" % (e,))
+                    break
+                if not data: break # lost connection
+                for byte in data:
+                    if mode == M_NORMAL:
+                        # interpret as command or as data
+                        if byte == IAC:
+                            mode = M_IAC_SEEN
+                        else:
+                            # store data in read buffer or sub option buffer
+                            # depending on state
+                            if suboption is not None:
+                                suboption.append(byte)
+                            else:
+                                self._read_buffer.put(byte)
+                    elif mode == M_IAC_SEEN:
+                        if byte == IAC:
+                            # interpret as command doubled -> insert character
+                            # itself
+                            if suboption is not None:
+                                suboption.append(IAC)
+                            else:
+                                self._read_buffer.put(IAC)
+                            mode = M_NORMAL
+                        elif byte == SB:
+                            # sub option start
+                            suboption = bytearray()
+                            mode = M_NORMAL
+                        elif byte == SE:
+                            # sub option end -> process it now
+                            self._telnetProcessSubnegotiation(bytes(suboption))
+                            suboption = None
+                            mode = M_NORMAL
+                        elif byte in (DO, DONT, WILL, WONT):
+                            # negotiation
+                            telnet_command = byte
+                            mode = M_NEGOTIATE
+                        else:
+                            # other telnet commands
+                            self._telnetProcessCommand(byte)
+                            mode = M_NORMAL
+                    elif mode == M_NEGOTIATE: # DO, DONT, WILL, WONT was received, option now following
+                        self._telnetNegotiateOption(telnet_command, byte)
+                        mode = M_NORMAL
+        finally:
+            self._thread = None
+            if self.logger:
+                self.logger.debug("read thread terminated")
+
+    # - incoming telnet commands and options
+
+    def _telnetProcessCommand(self, command):
+        """Process commands other than DO, DONT, WILL, WONT."""
+        # Currently none. RFC2217 only uses negotiation and subnegotiation.
+        if self.logger:
+            self.logger.warning("ignoring Telnet command: %r" % (command,))
+
+    def _telnetNegotiateOption(self, command, option):
+        """Process incoming DO, DONT, WILL, WONT."""
+        # check our registered telnet options and forward command to them
+        # they know themselves if they have to answer or not
+        known = False
+        for item in self._telnet_options:
+            # can have more than one match! as some options are duplicated for
+            # 'us' and 'them'
+            if item.option == option:
+                item.process_incoming(command)
+                known = True
+        if not known:
+            # handle unknown options
+            # only answer to positive requests and deny them
+            if command == WILL or command == DO:
+                self.telnetSendOption((command == WILL and DONT or WONT), option)
+                if self.logger:
+                    self.logger.warning("rejected Telnet option: %r" % (option,))
+
+
+    def _telnetProcessSubnegotiation(self, suboption):
+        """Process subnegotiation, the data between IAC SB and IAC SE."""
+        if suboption[0:1] == COM_PORT_OPTION:
+            if suboption[1:2] == SERVER_NOTIFY_LINESTATE and len(suboption) >= 3:
+                self._linestate = ord(suboption[2:3]) # ensure it is a number
+                if self.logger:
+                    self.logger.info("NOTIFY_LINESTATE: %s" % self._linestate)
+            elif suboption[1:2] == SERVER_NOTIFY_MODEMSTATE and len(suboption) >= 3:
+                self._modemstate = ord(suboption[2:3]) # ensure it is a number
+                if self.logger:
+                    self.logger.info("NOTIFY_MODEMSTATE: %s" % self._modemstate)
+                # update time when we think that a poll would make sense
+                self._modemstate_expires = time.time() + 0.3
+            elif suboption[1:2] == FLOWCONTROL_SUSPEND:
+                self._remote_suspend_flow = True
+            elif suboption[1:2] == FLOWCONTROL_RESUME:
+                self._remote_suspend_flow = False
+            else:
+                for item in self._rfc2217_options.values():
+                    if item.ack_option == suboption[1:2]:
+                        #~ print "processing COM_PORT_OPTION: %r" % list(suboption[1:])
+                        item.checkAnswer(bytes(suboption[2:]))
+                        break
+                else:
+                    if self.logger:
+                        self.logger.warning("ignoring COM_PORT_OPTION: %r" % (suboption,))
+        else:
+            if self.logger:
+                self.logger.warning("ignoring subnegotiation: %r" % (suboption,))
+
+    # - outgoing telnet commands and options
+
+    def _internal_raw_write(self, data):
+        """internal socket write with no data escaping. used to send telnet stuff."""
+        self._write_lock.acquire()
+        try:
+            self._socket.sendall(data)
+        finally:
+            self._write_lock.release()
+
+    def telnetSendOption(self, action, option):
+        """Send DO, DONT, WILL, WONT."""
+        self._internal_raw_write(to_bytes([IAC, action, option]))
+
+    def rfc2217SendSubnegotiation(self, option, value=''):
+        """Subnegotiation of RFC2217 parameters."""
+        value = value.replace(IAC, IAC_DOUBLED)
+        self._internal_raw_write(to_bytes([IAC, SB, COM_PORT_OPTION, option] + list(value) + [IAC, SE]))
+
+    def rfc2217SendPurge(self, value):
+        item = self._rfc2217_options['purge']
+        item.set(value) # transmit desired purge type
+        item.wait(self._network_timeout) # wait for acknowledge from the server
+
+    def rfc2217SetControl(self, value):
+        item = self._rfc2217_options['control']
+        item.set(value) # transmit desired control type
+        if self._ignore_set_control_answer:
+            # answers are ignored when option is set. compatibility mode for
+            # servers that answer, but not the expected one... (or no answer
+            # at all) i.e. sredird
+            time.sleep(0.1)  # this helps getting the unit tests passed
+        else:
+            item.wait(self._network_timeout)  # wait for acknowledge from the server
+
+    def rfc2217FlowServerReady(self):
+        """\
+        check if server is ready to receive data. block for some time when
+        not.
+        """
+        #~ if self._remote_suspend_flow:
+            #~ wait---
+
+    def getModemState(self):
+        """\
+        get last modem state (cached value. If value is "old", request a new
+        one. This cache helps that we don't issue to many requests when e.g. all
+        status lines, one after the other is queried by the user (getCTS, getDSR
+        etc.)
+        """
+        # active modem state polling enabled? is the value fresh enough?
+        if self._poll_modem_state and self._modemstate_expires < time.time():
+            if self.logger:
+                self.logger.debug('polling modem state')
+            # when it is older, request an update
+            self.rfc2217SendSubnegotiation(NOTIFY_MODEMSTATE)
+            timeout_time = time.time() + self._network_timeout
+            while time.time() < timeout_time:
+                # when expiration time is updated, it means that there is a new
+                # value
+                if self._modemstate_expires > time.time():
+                    if self.logger:
+                        self.logger.warning('poll for modem state failed')
+                    break
+                time.sleep(0.001)    # prevent 100% CPU load
+            # even when there is a timeout, do not generate an error just
+            # return the last known value. this way we can support buggy
+            # servers that do not respond to polls, but send automatic
+            # updates.
+        if self._modemstate is not None:
+            if self.logger:
+                self.logger.debug('using cached modem state')
+            return self._modemstate
+        else:
+            # never received a notification from the server
+            raise SerialException("remote sends no NOTIFY_MODEMSTATE")
+
+
+# assemble Serial class with the platform specific implementation and the base
+# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
+# library, derive from io.RawIOBase
+try:
+    import io
+except ImportError:
+    # classic version with our own file-like emulation
+    class Serial(RFC2217Serial, FileLike):
+        pass
+else:
+    # io library present
+    class Serial(RFC2217Serial, io.RawIOBase):
+        pass
+
+
+#############################################################################
+# The following is code that helps implementing an RFC 2217 server.
+
+class PortManager(object):
+    """\
+    This class manages the state of Telnet and RFC 2217. It needs a serial
+    instance and a connection to work with. Connection is expected to implement
+    a (thread safe) write function, that writes the string to the network.
+    """
+
+    def __init__(self, serial_port, connection, logger=None):
+        self.serial = serial_port
+        self.connection = connection
+        self.logger = logger
+        self._client_is_rfc2217 = False
+
+        # filter state machine
+        self.mode = M_NORMAL
+        self.suboption = None
+        self.telnet_command = None
+
+        # states for modem/line control events
+        self.modemstate_mask = 255
+        self.last_modemstate = None
+        self.linstate_mask = 0
+
+        # all supported telnet options
+        self._telnet_options = [
+            TelnetOption(self, 'ECHO', ECHO, WILL, WONT, DO, DONT, REQUESTED),
+            TelnetOption(self, 'we-SGA', SGA, WILL, WONT, DO, DONT, REQUESTED),
+            TelnetOption(self, 'they-SGA', SGA, DO, DONT, WILL, WONT, INACTIVE),
+            TelnetOption(self, 'we-BINARY', BINARY, WILL, WONT, DO, DONT, INACTIVE),
+            TelnetOption(self, 'they-BINARY', BINARY, DO, DONT, WILL, WONT, REQUESTED),
+            TelnetOption(self, 'we-RFC2217', COM_PORT_OPTION, WILL, WONT, DO, DONT, REQUESTED, self._client_ok),
+            TelnetOption(self, 'they-RFC2217', COM_PORT_OPTION, DO, DONT, WILL, WONT, INACTIVE, self._client_ok),
+            ]
+
+        # negotiate Telnet/RFC2217 -> send initial requests
+        if self.logger:
+            self.logger.debug("requesting initial Telnet/RFC 2217 options")
+        for option in self._telnet_options:
+            if option.state is REQUESTED:
+                self.telnetSendOption(option.send_yes, option.option)
+        # issue 1st modem state notification
+
+    def _client_ok(self):
+        """\
+        callback of telnet option. It gets called when option is activated.
+        This one here is used to detect when the client agrees on RFC 2217. A
+        flag is set so that other functions like check_modem_lines know if the
+        client is OK.
+        """
+        # The callback is used for we and they so if one party agrees, we're
+        # already happy. it seems not all servers do the negotiation correctly
+        # and i guess there are incorrect clients too.. so be happy if client
+        # answers one or the other positively.
+        self._client_is_rfc2217 = True
+        if self.logger:
+            self.logger.info("client accepts RFC 2217")
+        # this is to ensure that the client gets a notification, even if there
+        # was no change
+        self.check_modem_lines(force_notification=True)
+
+    # - outgoing telnet commands and options
+
+    def telnetSendOption(self, action, option):
+        """Send DO, DONT, WILL, WONT."""
+        self.connection.write(to_bytes([IAC, action, option]))
+
+    def rfc2217SendSubnegotiation(self, option, value=''):
+        """Subnegotiation of RFC 2217 parameters."""
+        value = value.replace(IAC, IAC_DOUBLED)
+        self.connection.write(to_bytes([IAC, SB, COM_PORT_OPTION, option] + list(value) + [IAC, SE]))
+
+    # - check modem lines, needs to be called periodically from user to
+    # establish polling
+
+    def check_modem_lines(self, force_notification=False):
+        modemstate = (
+            (self.serial.getCTS() and MODEMSTATE_MASK_CTS) |
+            (self.serial.getDSR() and MODEMSTATE_MASK_DSR) |
+            (self.serial.getRI() and MODEMSTATE_MASK_RI) |
+            (self.serial.getCD() and MODEMSTATE_MASK_CD)
+        )
+        # check what has changed
+        deltas = modemstate ^ (self.last_modemstate or 0) # when last is None -> 0
+        if deltas & MODEMSTATE_MASK_CTS:
+            modemstate |= MODEMSTATE_MASK_CTS_CHANGE
+        if deltas & MODEMSTATE_MASK_DSR:
+            modemstate |= MODEMSTATE_MASK_DSR_CHANGE
+        if deltas & MODEMSTATE_MASK_RI:
+            modemstate |= MODEMSTATE_MASK_RI_CHANGE
+        if deltas & MODEMSTATE_MASK_CD:
+            modemstate |= MODEMSTATE_MASK_CD_CHANGE
+        # if new state is different and the mask allows this change, send
+        # notification. suppress notifications when client is not rfc2217
+        if modemstate != self.last_modemstate or force_notification:
+            if (self._client_is_rfc2217 and (modemstate & self.modemstate_mask)) or force_notification:
+                self.rfc2217SendSubnegotiation(
+                    SERVER_NOTIFY_MODEMSTATE,
+                    to_bytes([modemstate & self.modemstate_mask])
+                    )
+                if self.logger:
+                    self.logger.info("NOTIFY_MODEMSTATE: %s" % (modemstate,))
+            # save last state, but forget about deltas.
+            # otherwise it would also notify about changing deltas which is
+            # probably not very useful
+            self.last_modemstate = modemstate & 0xf0
+
+    # - outgoing data escaping
+
+    def escape(self, data):
+        """\
+        This generator function is for the user. All outgoing data has to be
+        properly escaped, so that no IAC character in the data stream messes up
+        the Telnet state machine in the server.
+
+        socket.sendall(escape(data))
+        """
+        for byte in data:
+            if byte == IAC:
+                yield IAC
+                yield IAC
+            else:
+                yield byte
+
+    # - incoming data filter
+
+    def filter(self, data):
+        """\
+        Handle a bunch of incoming bytes. This is a generator. It will yield
+        all characters not of interest for Telnet/RFC 2217.
+
+        The idea is that the reader thread pushes data from the socket through
+        this filter:
+
+        for byte in filter(socket.recv(1024)):
+            # do things like CR/LF conversion/whatever
+            # and write data to the serial port
+            serial.write(byte)
+
+        (socket error handling code left as exercise for the reader)
+        """
+        for byte in data:
+            if self.mode == M_NORMAL:
+                # interpret as command or as data
+                if byte == IAC:
+                    self.mode = M_IAC_SEEN
+                else:
+                    # store data in sub option buffer or pass it to our
+                    # consumer depending on state
+                    if self.suboption is not None:
+                        self.suboption.append(byte)
+                    else:
+                        yield byte
+            elif self.mode == M_IAC_SEEN:
+                if byte == IAC:
+                    # interpret as command doubled -> insert character
+                    # itself
+                    if self.suboption is not None:
+                        self.suboption.append(byte)
+                    else:
+                        yield byte
+                    self.mode = M_NORMAL
+                elif byte == SB:
+                    # sub option start
+                    self.suboption = bytearray()
+                    self.mode = M_NORMAL
+                elif byte == SE:
+                    # sub option end -> process it now
+                    self._telnetProcessSubnegotiation(bytes(self.suboption))
+                    self.suboption = None
+                    self.mode = M_NORMAL
+                elif byte in (DO, DONT, WILL, WONT):
+                    # negotiation
+                    self.telnet_command = byte
+                    self.mode = M_NEGOTIATE
+                else:
+                    # other telnet commands
+                    self._telnetProcessCommand(byte)
+                    self.mode = M_NORMAL
+            elif self.mode == M_NEGOTIATE: # DO, DONT, WILL, WONT was received, option now following
+                self._telnetNegotiateOption(self.telnet_command, byte)
+                self.mode = M_NORMAL
+
+    # - incoming telnet commands and options
+
+    def _telnetProcessCommand(self, command):
+        """Process commands other than DO, DONT, WILL, WONT."""
+        # Currently none. RFC2217 only uses negotiation and subnegotiation.
+        if self.logger:
+            self.logger.warning("ignoring Telnet command: %r" % (command,))
+
+    def _telnetNegotiateOption(self, command, option):
+        """Process incoming DO, DONT, WILL, WONT."""
+        # check our registered telnet options and forward command to them
+        # they know themselves if they have to answer or not
+        known = False
+        for item in self._telnet_options:
+            # can have more than one match! as some options are duplicated for
+            # 'us' and 'them'
+            if item.option == option:
+                item.process_incoming(command)
+                known = True
+        if not known:
+            # handle unknown options
+            # only answer to positive requests and deny them
+            if command == WILL or command == DO:
+                self.telnetSendOption((command == WILL and DONT or WONT), option)
+                if self.logger:
+                    self.logger.warning("rejected Telnet option: %r" % (option,))
+
+
+    def _telnetProcessSubnegotiation(self, suboption):
+        """Process subnegotiation, the data between IAC SB and IAC SE."""
+        if suboption[0:1] == COM_PORT_OPTION:
+            if self.logger:
+                self.logger.debug('received COM_PORT_OPTION: %r' % (suboption,))
+            if suboption[1:2] == SET_BAUDRATE:
+                backup = self.serial.baudrate
+                try:
+                    (baudrate,) = struct.unpack("!I", suboption[2:6])
+                    if baudrate != 0:
+                        self.serial.baudrate = baudrate
+                except ValueError, e:
+                    if self.logger:
+                        self.logger.error("failed to set baud rate: %s" % (e,))
+                    self.serial.baudrate = backup
+                else:
+                    if self.logger:
+                        self.logger.info("%s baud rate: %s" % (baudrate and 'set' or 'get', self.serial.baudrate))
+                self.rfc2217SendSubnegotiation(SERVER_SET_BAUDRATE, struct.pack("!I", self.serial.baudrate))
+            elif suboption[1:2] == SET_DATASIZE:
+                backup = self.serial.bytesize
+                try:
+                    (datasize,) = struct.unpack("!B", suboption[2:3])
+                    if datasize != 0:
+                        self.serial.bytesize = datasize
+                except ValueError, e:
+                    if self.logger:
+                        self.logger.error("failed to set data size: %s" % (e,))
+                    self.serial.bytesize = backup
+                else:
+                    if self.logger:
+                        self.logger.info("%s data size: %s" % (datasize and 'set' or 'get', self.serial.bytesize))
+                self.rfc2217SendSubnegotiation(SERVER_SET_DATASIZE, struct.pack("!B", self.serial.bytesize))
+            elif suboption[1:2] == SET_PARITY:
+                backup = self.serial.parity
+                try:
+                    parity = struct.unpack("!B", suboption[2:3])[0]
+                    if parity != 0:
+                            self.serial.parity = RFC2217_REVERSE_PARITY_MAP[parity]
+                except ValueError, e:
+                    if self.logger:
+                        self.logger.error("failed to set parity: %s" % (e,))
+                    self.serial.parity = backup
+                else:
+                    if self.logger:
+                        self.logger.info("%s parity: %s" % (parity and 'set' or 'get', self.serial.parity))
+                self.rfc2217SendSubnegotiation(
+                    SERVER_SET_PARITY,
+                    struct.pack("!B", RFC2217_PARITY_MAP[self.serial.parity])
+                    )
+            elif suboption[1:2] == SET_STOPSIZE:
+                backup = self.serial.stopbits
+                try:
+                    stopbits = struct.unpack("!B", suboption[2:3])[0]
+                    if stopbits != 0:
+                        self.serial.stopbits = RFC2217_REVERSE_STOPBIT_MAP[stopbits]
+                except ValueError, e:
+                    if self.logger:
+                        self.logger.error("failed to set stop bits: %s" % (e,))
+                    self.serial.stopbits = backup
+                else:
+                    if self.logger:
+                        self.logger.info("%s stop bits: %s" % (stopbits and 'set' or 'get', self.serial.stopbits))
+                self.rfc2217SendSubnegotiation(
+                    SERVER_SET_STOPSIZE,
+                    struct.pack("!B", RFC2217_STOPBIT_MAP[self.serial.stopbits])
+                    )
+            elif suboption[1:2] == SET_CONTROL:
+                if suboption[2:3] == SET_CONTROL_REQ_FLOW_SETTING:
+                    if self.serial.xonxoff:
+                        self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_SW_FLOW_CONTROL)
+                    elif self.serial.rtscts:
+                        self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_HW_FLOW_CONTROL)
+                    else:
+                        self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_NO_FLOW_CONTROL)
+                elif suboption[2:3] == SET_CONTROL_USE_NO_FLOW_CONTROL:
+                    self.serial.xonxoff = False
+                    self.serial.rtscts = False
+                    if self.logger:
+                        self.logger.info("changed flow control to None")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_NO_FLOW_CONTROL)
+                elif suboption[2:3] == SET_CONTROL_USE_SW_FLOW_CONTROL:
+                    self.serial.xonxoff = True
+                    if self.logger:
+                        self.logger.info("changed flow control to XON/XOFF")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_SW_FLOW_CONTROL)
+                elif suboption[2:3] == SET_CONTROL_USE_HW_FLOW_CONTROL:
+                    self.serial.rtscts = True
+                    if self.logger:
+                        self.logger.info("changed flow control to RTS/CTS")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_USE_HW_FLOW_CONTROL)
+                elif suboption[2:3] == SET_CONTROL_REQ_BREAK_STATE:
+                    if self.logger:
+                        self.logger.warning("requested break state - not implemented")
+                    pass # XXX needs cached value
+                elif suboption[2:3] == SET_CONTROL_BREAK_ON:
+                    self.serial.setBreak(True)
+                    if self.logger:
+                        self.logger.info("changed BREAK to active")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_BREAK_ON)
+                elif suboption[2:3] == SET_CONTROL_BREAK_OFF:
+                    self.serial.setBreak(False)
+                    if self.logger:
+                        self.logger.info("changed BREAK to inactive")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_BREAK_OFF)
+                elif suboption[2:3] == SET_CONTROL_REQ_DTR:
+                    if self.logger:
+                        self.logger.warning("requested DTR state - not implemented")
+                    pass # XXX needs cached value
+                elif suboption[2:3] == SET_CONTROL_DTR_ON:
+                    self.serial.setDTR(True)
+                    if self.logger:
+                        self.logger.info("changed DTR to active")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_DTR_ON)
+                elif suboption[2:3] == SET_CONTROL_DTR_OFF:
+                    self.serial.setDTR(False)
+                    if self.logger:
+                        self.logger.info("changed DTR to inactive")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_DTR_OFF)
+                elif suboption[2:3] == SET_CONTROL_REQ_RTS:
+                    if self.logger:
+                        self.logger.warning("requested RTS state - not implemented")
+                    pass # XXX needs cached value
+                    #~ self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_ON)
+                elif suboption[2:3] == SET_CONTROL_RTS_ON:
+                    self.serial.setRTS(True)
+                    if self.logger:
+                        self.logger.info("changed RTS to active")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_ON)
+                elif suboption[2:3] == SET_CONTROL_RTS_OFF:
+                    self.serial.setRTS(False)
+                    if self.logger:
+                        self.logger.info("changed RTS to inactive")
+                    self.rfc2217SendSubnegotiation(SERVER_SET_CONTROL, SET_CONTROL_RTS_OFF)
+                #~ elif suboption[2:3] == SET_CONTROL_REQ_FLOW_SETTING_IN:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_NO_FLOW_CONTROL_IN:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_SW_FLOW_CONTOL_IN:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_HW_FLOW_CONTOL_IN:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_DCD_FLOW_CONTROL:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_DTR_FLOW_CONTROL:
+                #~ elif suboption[2:3] == SET_CONTROL_USE_DSR_FLOW_CONTROL:
+            elif suboption[1:2] == NOTIFY_LINESTATE:
+                # client polls for current state
+                self.rfc2217SendSubnegotiation(
+                    SERVER_NOTIFY_LINESTATE,
+                    to_bytes([0])   # sorry, nothing like that implemented
+                    )
+            elif suboption[1:2] == NOTIFY_MODEMSTATE:
+                if self.logger:
+                    self.logger.info("request for modem state")
+                # client polls for current state
+                self.check_modem_lines(force_notification=True)
+            elif suboption[1:2] == FLOWCONTROL_SUSPEND:
+                if self.logger:
+                    self.logger.info("suspend")
+                self._remote_suspend_flow = True
+            elif suboption[1:2] == FLOWCONTROL_RESUME:
+                if self.logger:
+                    self.logger.info("resume")
+                self._remote_suspend_flow = False
+            elif suboption[1:2] == SET_LINESTATE_MASK:
+                self.linstate_mask = ord(suboption[2:3]) # ensure it is a number
+                if self.logger:
+                    self.logger.info("line state mask: 0x%02x" % (self.linstate_mask,))
+            elif suboption[1:2] == SET_MODEMSTATE_MASK:
+                self.modemstate_mask = ord(suboption[2:3]) # ensure it is a number
+                if self.logger:
+                    self.logger.info("modem state mask: 0x%02x" % (self.modemstate_mask,))
+            elif suboption[1:2] == PURGE_DATA:
+                if suboption[2:3] == PURGE_RECEIVE_BUFFER:
+                    self.serial.flushInput()
+                    if self.logger:
+                        self.logger.info("purge in")
+                    self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_RECEIVE_BUFFER)
+                elif suboption[2:3] == PURGE_TRANSMIT_BUFFER:
+                    self.serial.flushOutput()
+                    if self.logger:
+                        self.logger.info("purge out")
+                    self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_TRANSMIT_BUFFER)
+                elif suboption[2:3] == PURGE_BOTH_BUFFERS:
+                    self.serial.flushInput()
+                    self.serial.flushOutput()
+                    if self.logger:
+                        self.logger.info("purge both")
+                    self.rfc2217SendSubnegotiation(SERVER_PURGE_DATA, PURGE_BOTH_BUFFERS)
+                else:
+                    if self.logger:
+                        self.logger.error("undefined PURGE_DATA: %r" % list(suboption[2:]))
+            else:
+                if self.logger:
+                    self.logger.error("undefined COM_PORT_OPTION: %r" % list(suboption[1:]))
+        else:
+            if self.logger:
+                self.logger.warning("unknown subnegotiation: %r" % (suboption,))
+
+
+# simple client test
+if __name__ == '__main__':
+    import sys
+    s = Serial('rfc2217://localhost:7000', 115200)
+    sys.stdout.write('%s\n' % s)
+
+    #~ s.baudrate = 1898
+
+    sys.stdout.write("write...\n")
+    s.write("hello\n")
+    s.flush()
+    sys.stdout.write("read: %s\n" % s.read(5))
+
+    #~ s.baudrate = 19200
+    #~ s.databits = 7
+    s.close()
diff --git a/scripts/serial/serialcli.py b/scripts/serial/serialcli.py
new file mode 100644
index 0000000000..9ab3876206
--- /dev/null
+++ b/scripts/serial/serialcli.py
@@ -0,0 +1,284 @@
+#! python
+# Python Serial Port Extension for Win32, Linux, BSD, Jython and .NET/Mono
+# serial driver for .NET/Mono (IronPython), .NET >= 2
+# see __init__.py
+#
+# (C) 2008 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+import clr
+import System
+import System.IO.Ports
+from serial.serialutil import *
+
+
+def device(portnum):
+    """Turn a port number into a device name"""
+    return System.IO.Ports.SerialPort.GetPortNames()[portnum]
+
+
+# must invoke function with byte array, make a helper to convert strings
+# to byte arrays
+sab = System.Array[System.Byte]
+def as_byte_array(string):
+    return sab([ord(x) for x in string])  # XXX will require adaption when run with a 3.x compatible IronPython
+
+class IronSerial(SerialBase):
+    """Serial port implementation for .NET/Mono."""
+
+    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+                9600, 19200, 38400, 57600, 115200)
+
+    def open(self):
+        """\
+        Open port with current settings. This may throw a SerialException
+        if the port cannot be opened.
+        """
+        if self._port is None:
+            raise SerialException("Port must be configured before it can be used.")
+        if self._isOpen:
+            raise SerialException("Port is already open.")
+        try:
+            self._port_handle = System.IO.Ports.SerialPort(self.portstr)
+        except Exception, msg:
+            self._port_handle = None
+            raise SerialException("could not open port %s: %s" % (self.portstr, msg))
+
+        self._reconfigurePort()
+        self._port_handle.Open()
+        self._isOpen = True
+        if not self._rtscts:
+            self.setRTS(True)
+            self.setDTR(True)
+        self.flushInput()
+        self.flushOutput()
+
+    def _reconfigurePort(self):
+        """Set communication parameters on opened port."""
+        if not self._port_handle:
+            raise SerialException("Can only operate on a valid port handle")
+
+        #~ self._port_handle.ReceivedBytesThreshold = 1
+
+        if self._timeout is None:
+            self._port_handle.ReadTimeout = System.IO.Ports.SerialPort.InfiniteTimeout
+        else:
+            self._port_handle.ReadTimeout = int(self._timeout*1000)
+
+        # if self._timeout != 0 and self._interCharTimeout is not None:
+            # timeouts = (int(self._interCharTimeout * 1000),) + timeouts[1:]
+
+        if self._writeTimeout is None:
+            self._port_handle.WriteTimeout = System.IO.Ports.SerialPort.InfiniteTimeout
+        else:
+            self._port_handle.WriteTimeout = int(self._writeTimeout*1000)
+
+
+        # Setup the connection info.
+        try:
+            self._port_handle.BaudRate = self._baudrate
+        except IOError, e:
+            # catch errors from illegal baudrate settings
+            raise ValueError(str(e))
+
+        if self._bytesize == FIVEBITS:
+            self._port_handle.DataBits     = 5
+        elif self._bytesize == SIXBITS:
+            self._port_handle.DataBits     = 6
+        elif self._bytesize == SEVENBITS:
+            self._port_handle.DataBits     = 7
+        elif self._bytesize == EIGHTBITS:
+            self._port_handle.DataBits     = 8
+        else:
+            raise ValueError("Unsupported number of data bits: %r" % self._bytesize)
+
+        if self._parity == PARITY_NONE:
+            self._port_handle.Parity       = getattr(System.IO.Ports.Parity, 'None') # reserved keyword in Py3k
+        elif self._parity == PARITY_EVEN:
+            self._port_handle.Parity       = System.IO.Ports.Parity.Even
+        elif self._parity == PARITY_ODD:
+            self._port_handle.Parity       = System.IO.Ports.Parity.Odd
+        elif self._parity == PARITY_MARK:
+            self._port_handle.Parity       = System.IO.Ports.Parity.Mark
+        elif self._parity == PARITY_SPACE:
+            self._port_handle.Parity       = System.IO.Ports.Parity.Space
+        else:
+            raise ValueError("Unsupported parity mode: %r" % self._parity)
+
+        if self._stopbits == STOPBITS_ONE:
+            self._port_handle.StopBits     = System.IO.Ports.StopBits.One
+        elif self._stopbits == STOPBITS_ONE_POINT_FIVE:
+            self._port_handle.StopBits     = System.IO.Ports.StopBits.OnePointFive
+        elif self._stopbits == STOPBITS_TWO:
+            self._port_handle.StopBits     = System.IO.Ports.StopBits.Two
+        else:
+            raise ValueError("Unsupported number of stop bits: %r" % self._stopbits)
+
+        if self._rtscts and self._xonxoff:
+            self._port_handle.Handshake  = System.IO.Ports.Handshake.RequestToSendXOnXOff
+        elif self._rtscts:
+            self._port_handle.Handshake  = System.IO.Ports.Handshake.RequestToSend
+        elif self._xonxoff:
+            self._port_handle.Handshake  = System.IO.Ports.Handshake.XOnXOff
+        else:
+            self._port_handle.Handshake  = getattr(System.IO.Ports.Handshake, 'None')   # reserved keyword in Py3k
+
+    #~ def __del__(self):
+        #~ self.close()
+
+    def close(self):
+        """Close port"""
+        if self._isOpen:
+            if self._port_handle:
+                try:
+                    self._port_handle.Close()
+                except System.IO.Ports.InvalidOperationException:
+                    # ignore errors. can happen for unplugged USB serial devices
+                    pass
+                self._port_handle = None
+            self._isOpen = False
+
+    def makeDeviceName(self, port):
+        try:
+            return device(port)
+        except TypeError, e:
+            raise SerialException(str(e))
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def inWaiting(self):
+        """Return the number of characters currently in the input buffer."""
+        if not self._port_handle: raise portNotOpenError
+        return self._port_handle.BytesToRead
+
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if not self._port_handle: raise portNotOpenError
+        # must use single byte reads as this is the only way to read
+        # without applying encodings
+        data = bytearray()
+        while size:
+            try:
+                data.append(self._port_handle.ReadByte())
+            except System.TimeoutException, e:
+                break
+            else:
+                size -= 1
+        return bytes(data)
+
+    def write(self, data):
+        """Output the given string over the serial port."""
+        if not self._port_handle: raise portNotOpenError
+        #~ if not isinstance(data, (bytes, bytearray)):
+            #~ raise TypeError('expected %s or bytearray, got %s' % (bytes, type(data)))
+        try:
+            # must call overloaded method with byte array argument
+            # as this is the only one not applying encodings
+            self._port_handle.Write(as_byte_array(data), 0, len(data))
+        except System.TimeoutException, e:
+            raise writeTimeoutError
+        return len(data)
+
+    def flushInput(self):
+        """Clear input buffer, discarding all that is in the buffer."""
+        if not self._port_handle: raise portNotOpenError
+        self._port_handle.DiscardInBuffer()
+
+    def flushOutput(self):
+        """\
+        Clear output buffer, aborting the current output and
+        discarding all that is in the buffer.
+        """
+        if not self._port_handle: raise portNotOpenError
+        self._port_handle.DiscardOutBuffer()
+
+    def sendBreak(self, duration=0.25):
+        """\
+        Send break condition. Timed, returns to idle state after given
+        duration.
+        """
+        if not self._port_handle: raise portNotOpenError
+        import time
+        self._port_handle.BreakState = True
+        time.sleep(duration)
+        self._port_handle.BreakState = False
+
+    def setBreak(self, level=True):
+        """
+        Set break: Controls TXD. When active, to transmitting is possible.
+        """
+        if not self._port_handle: raise portNotOpenError
+        self._port_handle.BreakState = bool(level)
+
+    def setRTS(self, level=True):
+        """Set terminal status line: Request To Send"""
+        if not self._port_handle: raise portNotOpenError
+        self._port_handle.RtsEnable = bool(level)
+
+    def setDTR(self, level=True):
+        """Set terminal status line: Data Terminal Ready"""
+        if not self._port_handle: raise portNotOpenError
+        self._port_handle.DtrEnable = bool(level)
+
+    def getCTS(self):
+        """Read terminal status line: Clear To Send"""
+        if not self._port_handle: raise portNotOpenError
+        return self._port_handle.CtsHolding
+
+    def getDSR(self):
+        """Read terminal status line: Data Set Ready"""
+        if not self._port_handle: raise portNotOpenError
+        return self._port_handle.DsrHolding
+
+    def getRI(self):
+        """Read terminal status line: Ring Indicator"""
+        if not self._port_handle: raise portNotOpenError
+        #~ return self._port_handle.XXX
+        return False #XXX an error would be better
+
+    def getCD(self):
+        """Read terminal status line: Carrier Detect"""
+        if not self._port_handle: raise portNotOpenError
+        return self._port_handle.CDHolding
+
+    # - - platform specific - - - -
+    # none
+
+
+# assemble Serial class with the platform specific implementation and the base
+# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
+# library, derive from io.RawIOBase
+try:
+    import io
+except ImportError:
+    # classic version with our own file-like emulation
+    class Serial(IronSerial, FileLike):
+        pass
+else:
+    # io library present
+    class Serial(IronSerial, io.RawIOBase):
+        pass
+
+
+# Nur Testfunktion!!
+if __name__ == '__main__':
+    import sys
+
+    s = Serial(0)
+    sys.stdio.write('%s\n' % s)
+
+    s = Serial()
+    sys.stdio.write('%s\n' % s)
+
+
+    s.baudrate = 19200
+    s.databits = 7
+    s.close()
+    s.port = 0
+    s.open()
+    sys.stdio.write('%s\n' % s)
+
diff --git a/scripts/serial/serialposix.py b/scripts/serial/serialposix.py
new file mode 100644
index 0000000000..359ad1b877
--- /dev/null
+++ b/scripts/serial/serialposix.py
@@ -0,0 +1,730 @@
+#!/usr/bin/env python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# module for serial IO for POSIX compatible systems, like Linux
+# see __init__.py
+#
+# (C) 2001-2010 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+#
+# parts based on code from Grant B. Edwards  <grante@visi.com>:
+#  ftp://ftp.visi.com/users/grante/python/PosixSerial.py
+#
+# references: http://www.easysw.com/~mike/serial/serial.html
+
+import sys, os, fcntl, termios, struct, select, errno, time
+from serial.serialutil import *
+
+# Do check the Python version as some constants have moved.
+if (sys.hexversion < 0x020100f0):
+    import TERMIOS
+else:
+    TERMIOS = termios
+
+if (sys.hexversion < 0x020200f0):
+    import FCNTL
+else:
+    FCNTL = fcntl
+
+# try to detect the OS so that a device can be selected...
+# this code block should supply a device() and set_special_baudrate() function
+# for the platform
+plat = sys.platform.lower()
+
+if   plat[:5] == 'linux':    # Linux (confirmed)
+
+    def device(port):
+        return '/dev/ttyS%d' % port
+
+    TCGETS2 = 0x802C542A
+    TCSETS2 = 0x402C542B
+    BOTHER = 0o010000
+
+    def set_special_baudrate(port, baudrate):
+        # right size is 44 on x86_64, allow for some growth
+        import array
+        buf = array.array('i', [0] * 64)
+
+        try:
+            # get serial_struct
+            FCNTL.ioctl(port.fd, TCGETS2, buf)
+            # set custom speed
+            buf[2] &= ~TERMIOS.CBAUD
+            buf[2] |= BOTHER
+            buf[9] = buf[10] = baudrate
+
+            # set serial_struct
+            res = FCNTL.ioctl(port.fd, TCSETS2, buf)
+        except IOError, e:
+            raise ValueError('Failed to set custom baud rate (%s): %s' % (baudrate, e))
+
+    baudrate_constants = {
+        0:       0000000,  # hang up
+        50:      0000001,
+        75:      0000002,
+        110:     0000003,
+        134:     0000004,
+        150:     0000005,
+        200:     0000006,
+        300:     0000007,
+        600:     0000010,
+        1200:    0000011,
+        1800:    0000012,
+        2400:    0000013,
+        4800:    0000014,
+        9600:    0000015,
+        19200:   0000016,
+        38400:   0000017,
+        57600:   0010001,
+        115200:  0010002,
+        230400:  0010003,
+        460800:  0010004,
+        500000:  0010005,
+        576000:  0010006,
+        921600:  0010007,
+        1000000: 0010010,
+        1152000: 0010011,
+        1500000: 0010012,
+        2000000: 0010013,
+        2500000: 0010014,
+        3000000: 0010015,
+        3500000: 0010016,
+        4000000: 0010017
+    }
+
+elif plat == 'cygwin':       # cygwin/win32 (confirmed)
+
+    def device(port):
+        return '/dev/com%d' % (port + 1)
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {
+        128000: 0x01003,
+        256000: 0x01005,
+        500000: 0x01007,
+        576000: 0x01008,
+        921600: 0x01009,
+        1000000: 0x0100a,
+        1152000: 0x0100b,
+        1500000: 0x0100c,
+        2000000: 0x0100d,
+        2500000: 0x0100e,
+        3000000: 0x0100f
+    }
+
+elif plat[:7] == 'openbsd':    # OpenBSD
+
+    def device(port):
+        return '/dev/cua%02d' % port
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:3] == 'bsd' or  \
+    plat[:7] == 'freebsd':
+
+    def device(port):
+        return '/dev/cuad%d' % port
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:6] == 'darwin':   # OS X
+
+    version = os.uname()[2].split('.')
+    # Tiger or above can support arbitrary serial speeds
+    if int(version[0]) >= 8:
+        def set_special_baudrate(port, baudrate):
+            # use IOKit-specific call to set up high speeds
+            import array, fcntl
+            buf = array.array('i', [baudrate])
+            IOSSIOSPEED = 0x80045402 #_IOW('T', 2, speed_t)
+            fcntl.ioctl(port.fd, IOSSIOSPEED, buf, 1)
+    else: # version < 8
+        def set_special_baudrate(port, baudrate):
+            raise ValueError("baud rate not supported")
+
+    def device(port):
+        return '/dev/cuad%d' % port
+
+    baudrate_constants = {}
+
+
+elif plat[:6] == 'netbsd':   # NetBSD 1.6 testing by Erk
+
+    def device(port):
+        return '/dev/dty%02d' % port
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:4] == 'irix':     # IRIX (partially tested)
+
+    def device(port):
+        return '/dev/ttyf%d' % (port+1) #XXX different device names depending on flow control
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:2] == 'hp':       # HP-UX (not tested)
+
+    def device(port):
+        return '/dev/tty%dp0' % (port+1)
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:5] == 'sunos':    # Solaris/SunOS (confirmed)
+
+    def device(port):
+        return '/dev/tty%c' % (ord('a')+port)
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+elif plat[:3] == 'aix':      # AIX
+
+    def device(port):
+        return '/dev/tty%d' % (port)
+
+    def set_special_baudrate(port, baudrate):
+        raise ValueError("sorry don't know how to handle non standard baud rate on this platform")
+
+    baudrate_constants = {}
+
+else:
+    # platform detection has failed...
+    sys.stderr.write("""\
+don't know how to number ttys on this system.
+! Use an explicit path (eg /dev/ttyS1) or send this information to
+! the author of this module:
+
+sys.platform = %r
+os.name = %r
+serialposix.py version = %s
+
+also add the device name of the serial port and where the
+counting starts for the first serial port.
+e.g. 'first serial port: /dev/ttyS0'
+and with a bit luck you can get this module running...
+""" % (sys.platform, os.name, VERSION))
+    # no exception, just continue with a brave attempt to build a device name
+    # even if the device name is not correct for the platform it has chances
+    # to work using a string with the real device name as port parameter.
+    def device(portum):
+        return '/dev/ttyS%d' % portnum
+    def set_special_baudrate(port, baudrate):
+        raise SerialException("sorry don't know how to handle non standard baud rate on this platform")
+    baudrate_constants = {}
+    #~ raise Exception, "this module does not run on this platform, sorry."
+
+# whats up with "aix", "beos", ....
+# they should work, just need to know the device names.
+
+
+# load some constants for later use.
+# try to use values from TERMIOS, use defaults from linux otherwise
+TIOCMGET  = hasattr(TERMIOS, 'TIOCMGET') and TERMIOS.TIOCMGET or 0x5415
+TIOCMBIS  = hasattr(TERMIOS, 'TIOCMBIS') and TERMIOS.TIOCMBIS or 0x5416
+TIOCMBIC  = hasattr(TERMIOS, 'TIOCMBIC') and TERMIOS.TIOCMBIC or 0x5417
+TIOCMSET  = hasattr(TERMIOS, 'TIOCMSET') and TERMIOS.TIOCMSET or 0x5418
+
+#TIOCM_LE = hasattr(TERMIOS, 'TIOCM_LE') and TERMIOS.TIOCM_LE or 0x001
+TIOCM_DTR = hasattr(TERMIOS, 'TIOCM_DTR') and TERMIOS.TIOCM_DTR or 0x002
+TIOCM_RTS = hasattr(TERMIOS, 'TIOCM_RTS') and TERMIOS.TIOCM_RTS or 0x004
+#TIOCM_ST = hasattr(TERMIOS, 'TIOCM_ST') and TERMIOS.TIOCM_ST or 0x008
+#TIOCM_SR = hasattr(TERMIOS, 'TIOCM_SR') and TERMIOS.TIOCM_SR or 0x010
+
+TIOCM_CTS = hasattr(TERMIOS, 'TIOCM_CTS') and TERMIOS.TIOCM_CTS or 0x020
+TIOCM_CAR = hasattr(TERMIOS, 'TIOCM_CAR') and TERMIOS.TIOCM_CAR or 0x040
+TIOCM_RNG = hasattr(TERMIOS, 'TIOCM_RNG') and TERMIOS.TIOCM_RNG or 0x080
+TIOCM_DSR = hasattr(TERMIOS, 'TIOCM_DSR') and TERMIOS.TIOCM_DSR or 0x100
+TIOCM_CD  = hasattr(TERMIOS, 'TIOCM_CD') and TERMIOS.TIOCM_CD or TIOCM_CAR
+TIOCM_RI  = hasattr(TERMIOS, 'TIOCM_RI') and TERMIOS.TIOCM_RI or TIOCM_RNG
+#TIOCM_OUT1 = hasattr(TERMIOS, 'TIOCM_OUT1') and TERMIOS.TIOCM_OUT1 or 0x2000
+#TIOCM_OUT2 = hasattr(TERMIOS, 'TIOCM_OUT2') and TERMIOS.TIOCM_OUT2 or 0x4000
+if hasattr(TERMIOS, 'TIOCINQ'):
+    TIOCINQ = TERMIOS.TIOCINQ
+else:
+    TIOCINQ = hasattr(TERMIOS, 'FIONREAD') and TERMIOS.FIONREAD or 0x541B
+TIOCOUTQ   = hasattr(TERMIOS, 'TIOCOUTQ') and TERMIOS.TIOCOUTQ or 0x5411
+
+TIOCM_zero_str = struct.pack('I', 0)
+TIOCM_RTS_str = struct.pack('I', TIOCM_RTS)
+TIOCM_DTR_str = struct.pack('I', TIOCM_DTR)
+
+TIOCSBRK  = hasattr(TERMIOS, 'TIOCSBRK') and TERMIOS.TIOCSBRK or 0x5427
+TIOCCBRK  = hasattr(TERMIOS, 'TIOCCBRK') and TERMIOS.TIOCCBRK or 0x5428
+
+CMSPAR = 010000000000 # Use "stick" (mark/space) parity
+
+
+class PosixSerial(SerialBase):
+    """\
+    Serial port class POSIX implementation. Serial port configuration is 
+    done with termios and fcntl. Runs on Linux and many other Un*x like
+    systems.
+    """
+
+    def open(self):
+        """\
+        Open port with current settings. This may throw a SerialException
+        if the port cannot be opened."""
+        if self._port is None:
+            raise SerialException("Port must be configured before it can be used.")
+        if self._isOpen:
+            raise SerialException("Port is already open.")
+        self.fd = None
+        # open
+        try:
+            self.fd = os.open(self.portstr, os.O_RDWR|os.O_NOCTTY|os.O_NONBLOCK)
+        except OSError, msg:
+            self.fd = None
+            raise SerialException(msg.errno, "could not open port %s: %s" % (self._port, msg))
+        #~ fcntl.fcntl(self.fd, FCNTL.F_SETFL, 0)  # set blocking
+
+        try:
+            self._reconfigurePort()
+        except:
+            try:
+                os.close(self.fd)
+            except:
+                # ignore any exception when closing the port
+                # also to keep original exception that happened when setting up
+                pass
+            self.fd = None
+            raise
+        else:
+            self._isOpen = True
+        self.flushInput()
+
+
+    def _reconfigurePort(self):
+        """Set communication parameters on opened port."""
+        if self.fd is None:
+            raise SerialException("Can only operate on a valid file descriptor")
+        custom_baud = None
+
+        vmin = vtime = 0                # timeout is done via select
+        if self._interCharTimeout is not None:
+            vmin = 1
+            vtime = int(self._interCharTimeout * 10)
+        try:
+            orig_attr = termios.tcgetattr(self.fd)
+            iflag, oflag, cflag, lflag, ispeed, ospeed, cc = orig_attr
+        except termios.error, msg:      # if a port is nonexistent but has a /dev file, it'll fail here
+            raise SerialException("Could not configure port: %s" % msg)
+        # set up raw mode / no echo / binary
+        cflag |=  (TERMIOS.CLOCAL|TERMIOS.CREAD)
+        lflag &= ~(TERMIOS.ICANON|TERMIOS.ECHO|TERMIOS.ECHOE|TERMIOS.ECHOK|TERMIOS.ECHONL|
+                     TERMIOS.ISIG|TERMIOS.IEXTEN) #|TERMIOS.ECHOPRT
+        for flag in ('ECHOCTL', 'ECHOKE'): # netbsd workaround for Erk
+            if hasattr(TERMIOS, flag):
+                lflag &= ~getattr(TERMIOS, flag)
+
+        oflag &= ~(TERMIOS.OPOST)
+        iflag &= ~(TERMIOS.INLCR|TERMIOS.IGNCR|TERMIOS.ICRNL|TERMIOS.IGNBRK)
+        if hasattr(TERMIOS, 'IUCLC'):
+            iflag &= ~TERMIOS.IUCLC
+        if hasattr(TERMIOS, 'PARMRK'):
+            iflag &= ~TERMIOS.PARMRK
+
+        # setup baud rate
+        try:
+            ispeed = ospeed = getattr(TERMIOS, 'B%s' % (self._baudrate))
+        except AttributeError:
+            try:
+                ispeed = ospeed = baudrate_constants[self._baudrate]
+            except KeyError:
+                #~ raise ValueError('Invalid baud rate: %r' % self._baudrate)
+                # may need custom baud rate, it isn't in our list.
+                ispeed = ospeed = getattr(TERMIOS, 'B38400')
+                try:
+                    custom_baud = int(self._baudrate) # store for later
+                except ValueError:
+                    raise ValueError('Invalid baud rate: %r' % self._baudrate)
+                else:
+                    if custom_baud < 0:
+                        raise ValueError('Invalid baud rate: %r' % self._baudrate)
+
+        # setup char len
+        cflag &= ~TERMIOS.CSIZE
+        if self._bytesize == 8:
+            cflag |= TERMIOS.CS8
+        elif self._bytesize == 7:
+            cflag |= TERMIOS.CS7
+        elif self._bytesize == 6:
+            cflag |= TERMIOS.CS6
+        elif self._bytesize == 5:
+            cflag |= TERMIOS.CS5
+        else:
+            raise ValueError('Invalid char len: %r' % self._bytesize)
+        # setup stop bits
+        if self._stopbits == STOPBITS_ONE:
+            cflag &= ~(TERMIOS.CSTOPB)
+        elif self._stopbits == STOPBITS_ONE_POINT_FIVE:
+            cflag |=  (TERMIOS.CSTOPB)  # XXX same as TWO.. there is no POSIX support for 1.5
+        elif self._stopbits == STOPBITS_TWO:
+            cflag |=  (TERMIOS.CSTOPB)
+        else:
+            raise ValueError('Invalid stop bit specification: %r' % self._stopbits)
+        # setup parity
+        iflag &= ~(TERMIOS.INPCK|TERMIOS.ISTRIP)
+        if self._parity == PARITY_NONE:
+            cflag &= ~(TERMIOS.PARENB|TERMIOS.PARODD)
+        elif self._parity == PARITY_EVEN:
+            cflag &= ~(TERMIOS.PARODD)
+            cflag |=  (TERMIOS.PARENB)
+        elif self._parity == PARITY_ODD:
+            cflag |=  (TERMIOS.PARENB|TERMIOS.PARODD)
+        elif self._parity == PARITY_MARK and plat[:5] == 'linux':
+            cflag |=  (TERMIOS.PARENB|CMSPAR|TERMIOS.PARODD)
+        elif self._parity == PARITY_SPACE and plat[:5] == 'linux':
+            cflag |=  (TERMIOS.PARENB|CMSPAR)
+            cflag &= ~(TERMIOS.PARODD)
+        else:
+            raise ValueError('Invalid parity: %r' % self._parity)
+        # setup flow control
+        # xonxoff
+        if hasattr(TERMIOS, 'IXANY'):
+            if self._xonxoff:
+                iflag |=  (TERMIOS.IXON|TERMIOS.IXOFF) #|TERMIOS.IXANY)
+            else:
+                iflag &= ~(TERMIOS.IXON|TERMIOS.IXOFF|TERMIOS.IXANY)
+        else:
+            if self._xonxoff:
+                iflag |=  (TERMIOS.IXON|TERMIOS.IXOFF)
+            else:
+                iflag &= ~(TERMIOS.IXON|TERMIOS.IXOFF)
+        # rtscts
+        if hasattr(TERMIOS, 'CRTSCTS'):
+            if self._rtscts:
+                cflag |=  (TERMIOS.CRTSCTS)
+            else:
+                cflag &= ~(TERMIOS.CRTSCTS)
+        elif hasattr(TERMIOS, 'CNEW_RTSCTS'):   # try it with alternate constant name
+            if self._rtscts:
+                cflag |=  (TERMIOS.CNEW_RTSCTS)
+            else:
+                cflag &= ~(TERMIOS.CNEW_RTSCTS)
+        # XXX should there be a warning if setting up rtscts (and xonxoff etc) fails??
+
+        # buffer
+        # vmin "minimal number of characters to be read. 0 for non blocking"
+        if vmin < 0 or vmin > 255:
+            raise ValueError('Invalid vmin: %r ' % vmin)
+        cc[TERMIOS.VMIN] = vmin
+        # vtime
+        if vtime < 0 or vtime > 255:
+            raise ValueError('Invalid vtime: %r' % vtime)
+        cc[TERMIOS.VTIME] = vtime
+        # activate settings
+        if [iflag, oflag, cflag, lflag, ispeed, ospeed, cc] != orig_attr:
+            termios.tcsetattr(self.fd, TERMIOS.TCSANOW, [iflag, oflag, cflag, lflag, ispeed, ospeed, cc])
+
+        # apply custom baud rate, if any
+        if custom_baud is not None:
+            set_special_baudrate(self, custom_baud)
+
+    def close(self):
+        """Close port"""
+        if self._isOpen:
+            if self.fd is not None:
+                os.close(self.fd)
+                self.fd = None
+            self._isOpen = False
+
+    def makeDeviceName(self, port):
+        return device(port)
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def inWaiting(self):
+        """Return the number of characters currently in the input buffer."""
+        #~ s = fcntl.ioctl(self.fd, TERMIOS.FIONREAD, TIOCM_zero_str)
+        s = fcntl.ioctl(self.fd, TIOCINQ, TIOCM_zero_str)
+        return struct.unpack('I',s)[0]
+
+    # select based implementation, proved to work on many systems
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if not self._isOpen: raise portNotOpenError
+        read = bytearray()
+        while len(read) < size:
+            try:
+                ready,_,_ = select.select([self.fd],[],[], self._timeout)
+                # If select was used with a timeout, and the timeout occurs, it
+                # returns with empty lists -> thus abort read operation.
+                # For timeout == 0 (non-blocking operation) also abort when there
+                # is nothing to read.
+                if not ready:
+                    break   # timeout
+                buf = os.read(self.fd, size-len(read))
+                # read should always return some data as select reported it was
+                # ready to read when we get to this point.
+                if not buf:
+                    # Disconnected devices, at least on Linux, show the
+                    # behavior that they are always ready to read immediately
+                    # but reading returns nothing.
+                    raise SerialException('device reports readiness to read but returned no data (device disconnected or multiple access on port?)')
+                read.extend(buf)
+            except OSError, e:
+                # this is for Python 3.x where select.error is a subclass of OSError
+                # ignore EAGAIN errors. all other errors are shown
+                if e.errno != errno.EAGAIN:
+                    raise SerialException('read failed: %s' % (e,))
+            except select.error, e:
+                # this is for Python 2.x
+                # ignore EAGAIN errors. all other errors are shown
+                # see also http://www.python.org/dev/peps/pep-3151/#select
+                if e[0] != errno.EAGAIN:
+                    raise SerialException('read failed: %s' % (e,))
+        return bytes(read)
+
+    def write(self, data):
+        """Output the given string over the serial port."""
+        if not self._isOpen: raise portNotOpenError
+        d = to_bytes(data)
+        tx_len = len(d)
+        if self._writeTimeout is not None and self._writeTimeout > 0:
+            timeout = time.time() + self._writeTimeout
+        else:
+            timeout = None
+        while tx_len > 0:
+            try:
+                n = os.write(self.fd, d)
+                if timeout:
+                    # when timeout is set, use select to wait for being ready
+                    # with the time left as timeout
+                    timeleft = timeout - time.time()
+                    if timeleft < 0:
+                        raise writeTimeoutError
+                    _, ready, _ = select.select([], [self.fd], [], timeleft)
+                    if not ready:
+                        raise writeTimeoutError
+                else:
+                    # wait for write operation
+                    _, ready, _ = select.select([], [self.fd], [], None)
+                    if not ready:
+                        raise SerialException('write failed (select)')
+                d = d[n:]
+                tx_len -= n
+            except OSError, v:
+                if v.errno != errno.EAGAIN:
+                    raise SerialException('write failed: %s' % (v,))
+        return len(data)
+
+    def flush(self):
+        """\
+        Flush of file like objects. In this case, wait until all data
+        is written.
+        """
+        self.drainOutput()
+
+    def flushInput(self):
+        """Clear input buffer, discarding all that is in the buffer."""
+        if not self._isOpen: raise portNotOpenError
+        termios.tcflush(self.fd, TERMIOS.TCIFLUSH)
+
+    def flushOutput(self):
+        """\
+        Clear output buffer, aborting the current output and discarding all
+        that is in the buffer.
+        """
+        if not self._isOpen: raise portNotOpenError
+        termios.tcflush(self.fd, TERMIOS.TCOFLUSH)
+
+    def sendBreak(self, duration=0.25):
+        """\
+        Send break condition. Timed, returns to idle state after given
+        duration.
+        """
+        if not self._isOpen: raise portNotOpenError
+        termios.tcsendbreak(self.fd, int(duration/0.25))
+
+    def setBreak(self, level=1):
+        """\
+        Set break: Controls TXD. When active, no transmitting is possible.
+        """
+        if self.fd is None: raise portNotOpenError
+        if level:
+            fcntl.ioctl(self.fd, TIOCSBRK)
+        else:
+            fcntl.ioctl(self.fd, TIOCCBRK)
+
+    def setRTS(self, level=1):
+        """Set terminal status line: Request To Send"""
+        if not self._isOpen: raise portNotOpenError
+        if level:
+            fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_RTS_str)
+        else:
+            fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_RTS_str)
+
+    def setDTR(self, level=1):
+        """Set terminal status line: Data Terminal Ready"""
+        if not self._isOpen: raise portNotOpenError
+        if level:
+            fcntl.ioctl(self.fd, TIOCMBIS, TIOCM_DTR_str)
+        else:
+            fcntl.ioctl(self.fd, TIOCMBIC, TIOCM_DTR_str)
+
+    def getCTS(self):
+        """Read terminal status line: Clear To Send"""
+        if not self._isOpen: raise portNotOpenError
+        s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
+        return struct.unpack('I',s)[0] & TIOCM_CTS != 0
+
+    def getDSR(self):
+        """Read terminal status line: Data Set Ready"""
+        if not self._isOpen: raise portNotOpenError
+        s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
+        return struct.unpack('I',s)[0] & TIOCM_DSR != 0
+
+    def getRI(self):
+        """Read terminal status line: Ring Indicator"""
+        if not self._isOpen: raise portNotOpenError
+        s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
+        return struct.unpack('I',s)[0] & TIOCM_RI != 0
+
+    def getCD(self):
+        """Read terminal status line: Carrier Detect"""
+        if not self._isOpen: raise portNotOpenError
+        s = fcntl.ioctl(self.fd, TIOCMGET, TIOCM_zero_str)
+        return struct.unpack('I',s)[0] & TIOCM_CD != 0
+
+    # - - platform specific - - - -
+
+    def outWaiting(self):
+        """Return the number of characters currently in the output buffer."""
+        #~ s = fcntl.ioctl(self.fd, TERMIOS.FIONREAD, TIOCM_zero_str)
+        s = fcntl.ioctl(self.fd, TIOCOUTQ, TIOCM_zero_str)
+        return struct.unpack('I',s)[0]
+
+    def drainOutput(self):
+        """internal - not portable!"""
+        if not self._isOpen: raise portNotOpenError
+        termios.tcdrain(self.fd)
+
+    def nonblocking(self):
+        """internal - not portable!"""
+        if not self._isOpen: raise portNotOpenError
+        fcntl.fcntl(self.fd, FCNTL.F_SETFL, os.O_NONBLOCK)
+
+    def fileno(self):
+        """\
+        For easier use of the serial port instance with select.
+        WARNING: this function is not portable to different platforms!
+        """
+        if not self._isOpen: raise portNotOpenError
+        return self.fd
+
+    def setXON(self, level=True):
+        """\
+        Manually control flow - when software flow control is enabled.
+        This will send XON (true) and XOFF (false) to the other device.
+        WARNING: this function is not portable to different platforms!
+        """
+        if not self.hComPort: raise portNotOpenError
+        if enable:
+            termios.tcflow(self.fd, TERMIOS.TCION)
+        else:
+            termios.tcflow(self.fd, TERMIOS.TCIOFF)
+
+    def flowControlOut(self, enable):
+        """\
+        Manually control flow of outgoing data - when hardware or software flow
+        control is enabled.
+        WARNING: this function is not portable to different platforms!
+        """
+        if not self._isOpen: raise portNotOpenError
+        if enable:
+            termios.tcflow(self.fd, TERMIOS.TCOON)
+        else:
+            termios.tcflow(self.fd, TERMIOS.TCOOFF)
+
+
+# assemble Serial class with the platform specific implementation and the base
+# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
+# library, derive from io.RawIOBase
+try:
+    import io
+except ImportError:
+    # classic version with our own file-like emulation
+    class Serial(PosixSerial, FileLike):
+        pass
+else:
+    # io library present
+    class Serial(PosixSerial, io.RawIOBase):
+        pass
+
+class PosixPollSerial(Serial):
+    """\
+    Poll based read implementation. Not all systems support poll properly.
+    However this one has better handling of errors, such as a device
+    disconnecting while it's in use (e.g. USB-serial unplugged).
+    """
+
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if self.fd is None: raise portNotOpenError
+        read = bytearray()
+        poll = select.poll()
+        poll.register(self.fd, select.POLLIN|select.POLLERR|select.POLLHUP|select.POLLNVAL)
+        if size > 0:
+            while len(read) < size:
+                # print "\tread(): size",size, "have", len(read)    #debug
+                # wait until device becomes ready to read (or something fails)
+                for fd, event in poll.poll(self._timeout*1000):
+                    if event & (select.POLLERR|select.POLLHUP|select.POLLNVAL):
+                        raise SerialException('device reports error (poll)')
+                    #  we don't care if it is select.POLLIN or timeout, that's
+                    #  handled below
+                buf = os.read(self.fd, size - len(read))
+                read.extend(buf)
+                if ((self._timeout is not None and self._timeout >= 0) or 
+                    (self._interCharTimeout is not None and self._interCharTimeout > 0)) and not buf:
+                    break   # early abort on timeout
+        return bytes(read)
+
+
+if __name__ == '__main__':
+    s = Serial(0,
+                 baudrate=19200,        # baud rate
+                 bytesize=EIGHTBITS,    # number of data bits
+                 parity=PARITY_EVEN,    # enable parity checking
+                 stopbits=STOPBITS_ONE, # number of stop bits
+                 timeout=3,             # set a timeout value, None for waiting forever
+                 xonxoff=0,             # enable software flow control
+                 rtscts=0,              # enable RTS/CTS flow control
+               )
+    s.setRTS(1)
+    s.setDTR(1)
+    s.flushInput()
+    s.flushOutput()
+    s.write('hello')
+    sys.stdout.write('%r\n' % s.read(5))
+    sys.stdout.write('%s\n' % s.inWaiting())
+    del s
+
diff --git a/scripts/serial/serialutil.py b/scripts/serial/serialutil.py
new file mode 100644
index 0000000000..af0d2f6402
--- /dev/null
+++ b/scripts/serial/serialutil.py
@@ -0,0 +1,572 @@
+#! python
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see __init__.py
+#
+# (C) 2001-2010 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+# compatibility for older Python < 2.6
+try:
+    bytes
+    bytearray
+except (NameError, AttributeError):
+    # Python older than 2.6 do not have these types. Like for Python 2.6 they
+    # should behave like str. For Python older than 3.0 we want to work with
+    # strings anyway, only later versions have a true bytes type.
+    bytes = str
+    # bytearray is a mutable type that is easily turned into an instance of
+    # bytes
+    class bytearray(list):
+        # for bytes(bytearray()) usage
+        def __str__(self): return ''.join(self)
+        def __repr__(self): return 'bytearray(%r)' % ''.join(self)
+        # append automatically converts integers to characters
+        def append(self, item):
+            if isinstance(item, str):
+                list.append(self, item)
+            else:
+                list.append(self, chr(item))
+        # +=
+        def __iadd__(self, other):
+            for byte in other:
+                self.append(byte)
+            return self
+
+        def __getslice__(self, i, j):
+            return bytearray(list.__getslice__(self, i, j))
+
+        def __getitem__(self, item):
+            if isinstance(item, slice):
+                return bytearray(list.__getitem__(self, item))
+            else:
+                return ord(list.__getitem__(self, item))
+
+        def __eq__(self, other):
+            if isinstance(other, basestring):
+                other = bytearray(other)
+            return list.__eq__(self, other)
+
+# ``memoryview`` was introduced in Python 2.7 and ``bytes(some_memoryview)``
+# isn't returning the contents (very unfortunate). Therefore we need special
+# cases and test for it. Ensure that there is a ``memoryview`` object for older
+# Python versions. This is easier than making every test dependent on its
+# existence.
+try:
+    memoryview
+except (NameError, AttributeError):
+    # implementation does not matter as we do not realy use it.
+    # it just must not inherit from something else we might care for.
+    class memoryview:
+        pass
+
+
+# all Python versions prior 3.x convert ``str([17])`` to '[17]' instead of '\x11'
+# so a simple ``bytes(sequence)`` doesn't work for all versions
+def to_bytes(seq):
+    """convert a sequence to a bytes type"""
+    if isinstance(seq, bytes):
+        return seq
+    elif isinstance(seq, bytearray):
+        return bytes(seq)
+    elif isinstance(seq, memoryview):
+        return seq.tobytes()
+    else:
+        b = bytearray()
+        for item in seq:
+            b.append(item)  # this one handles int and str for our emulation and ints for Python 3.x
+        return bytes(b)
+
+# create control bytes
+XON  = to_bytes([17])
+XOFF = to_bytes([19])
+
+CR = to_bytes([13])
+LF = to_bytes([10])
+
+
+PARITY_NONE, PARITY_EVEN, PARITY_ODD, PARITY_MARK, PARITY_SPACE = 'N', 'E', 'O', 'M', 'S'
+STOPBITS_ONE, STOPBITS_ONE_POINT_FIVE, STOPBITS_TWO = (1, 1.5, 2)
+FIVEBITS, SIXBITS, SEVENBITS, EIGHTBITS = (5, 6, 7, 8)
+
+PARITY_NAMES = {
+    PARITY_NONE:  'None',
+    PARITY_EVEN:  'Even',
+    PARITY_ODD:   'Odd',
+    PARITY_MARK:  'Mark',
+    PARITY_SPACE: 'Space',
+}
+
+
+class SerialException(IOError):
+    """Base class for serial port related exceptions."""
+
+
+class SerialTimeoutException(SerialException):
+    """Write timeouts give an exception"""
+
+
+writeTimeoutError = SerialTimeoutException('Write timeout')
+portNotOpenError = SerialException('Attempting to use a port that is not open')
+
+
+class FileLike(object):
+    """\
+    An abstract file like class.
+
+    This class implements readline and readlines based on read and
+    writelines based on write.
+    This class is used to provide the above functions for to Serial
+    port objects.
+
+    Note that when the serial port was opened with _NO_ timeout that
+    readline blocks until it sees a newline (or the specified size is
+    reached) and that readlines would never return and therefore
+    refuses to work (it raises an exception in this case)!
+    """
+
+    def __init__(self):
+        self.closed = True
+
+    def close(self):
+        self.closed = True
+
+    # so that ports are closed when objects are discarded
+    def __del__(self):
+        """Destructor.  Calls close()."""
+        # The try/except block is in case this is called at program
+        # exit time, when it's possible that globals have already been
+        # deleted, and then the close() call might fail.  Since
+        # there's nothing we can do about such failures and they annoy
+        # the end users, we suppress the traceback.
+        try:
+            self.close()
+        except:
+            pass
+
+    def writelines(self, sequence):
+        for line in sequence:
+            self.write(line)
+
+    def flush(self):
+        """flush of file like objects"""
+        pass
+
+    # iterator for e.g. "for line in Serial(0): ..." usage
+    def next(self):
+        line = self.readline()
+        if not line: raise StopIteration
+        return line
+
+    def __iter__(self):
+        return self
+
+    def readline(self, size=None, eol=LF):
+        """\
+        Read a line which is terminated with end-of-line (eol) character
+        ('\n' by default) or until timeout.
+        """
+        leneol = len(eol)
+        line = bytearray()
+        while True:
+            c = self.read(1)
+            if c:
+                line += c
+                if line[-leneol:] == eol:
+                    break
+                if size is not None and len(line) >= size:
+                    break
+            else:
+                break
+        return bytes(line)
+
+    def readlines(self, sizehint=None, eol=LF):
+        """\
+        Read a list of lines, until timeout.
+        sizehint is ignored.
+        """
+        if self.timeout is None:
+            raise ValueError("Serial port MUST have enabled timeout for this function!")
+        leneol = len(eol)
+        lines = []
+        while True:
+            line = self.readline(eol=eol)
+            if line:
+                lines.append(line)
+                if line[-leneol:] != eol:    # was the line received with a timeout?
+                    break
+            else:
+                break
+        return lines
+
+    def xreadlines(self, sizehint=None):
+        """\
+        Read lines, implemented as generator. It will raise StopIteration on
+        timeout (empty read). sizehint is ignored.
+        """
+        while True:
+            line = self.readline()
+            if not line: break
+            yield line
+
+    # other functions of file-likes - not used by pySerial
+
+    #~ readinto(b)
+
+    def seek(self, pos, whence=0):
+        raise IOError("file is not seekable")
+
+    def tell(self):
+        raise IOError("file is not seekable")
+
+    def truncate(self, n=None):
+        raise IOError("file is not seekable")
+
+    def isatty(self):
+        return False
+
+
+class SerialBase(object):
+    """\
+    Serial port base class. Provides __init__ function and properties to
+    get/set port settings.
+    """
+
+    # default values, may be overridden in subclasses that do not support all values
+    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+                 9600, 19200, 38400, 57600, 115200, 230400, 460800, 500000,
+                 576000, 921600, 1000000, 1152000, 1500000, 2000000, 2500000,
+                 3000000, 3500000, 4000000)
+    BYTESIZES = (FIVEBITS, SIXBITS, SEVENBITS, EIGHTBITS)
+    PARITIES  = (PARITY_NONE, PARITY_EVEN, PARITY_ODD, PARITY_MARK, PARITY_SPACE)
+    STOPBITS  = (STOPBITS_ONE, STOPBITS_ONE_POINT_FIVE, STOPBITS_TWO)
+
+    def __init__(self,
+                 port = None,           # number of device, numbering starts at
+                                        # zero. if everything fails, the user
+                                        # can specify a device string, note
+                                        # that this isn't portable anymore
+                                        # port will be opened if one is specified
+                 baudrate=9600,         # baud rate
+                 bytesize=EIGHTBITS,    # number of data bits
+                 parity=PARITY_NONE,    # enable parity checking
+                 stopbits=STOPBITS_ONE, # number of stop bits
+                 timeout=None,          # set a timeout value, None to wait forever
+                 xonxoff=False,         # enable software flow control
+                 rtscts=False,          # enable RTS/CTS flow control
+                 writeTimeout=None,     # set a timeout for writes
+                 dsrdtr=False,          # None: use rtscts setting, dsrdtr override if True or False
+                 interCharTimeout=None  # Inter-character timeout, None to disable
+                 ):
+        """\
+        Initialize comm port object. If a port is given, then the port will be
+        opened immediately. Otherwise a Serial port object in closed state
+        is returned.
+        """
+
+        self._isOpen   = False
+        self._port     = None           # correct value is assigned below through properties
+        self._baudrate = None           # correct value is assigned below through properties
+        self._bytesize = None           # correct value is assigned below through properties
+        self._parity   = None           # correct value is assigned below through properties
+        self._stopbits = None           # correct value is assigned below through properties
+        self._timeout  = None           # correct value is assigned below through properties
+        self._writeTimeout = None       # correct value is assigned below through properties
+        self._xonxoff  = None           # correct value is assigned below through properties
+        self._rtscts   = None           # correct value is assigned below through properties
+        self._dsrdtr   = None           # correct value is assigned below through properties
+        self._interCharTimeout = None   # correct value is assigned below through properties
+
+        # assign values using get/set methods using the properties feature
+        self.port     = port
+        self.baudrate = baudrate
+        self.bytesize = bytesize
+        self.parity   = parity
+        self.stopbits = stopbits
+        self.timeout  = timeout
+        self.writeTimeout = writeTimeout
+        self.xonxoff  = xonxoff
+        self.rtscts   = rtscts
+        self.dsrdtr   = dsrdtr
+        self.interCharTimeout = interCharTimeout
+
+        if port is not None:
+            self.open()
+
+    def isOpen(self):
+        """Check if the port is opened."""
+        return self._isOpen
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    # TODO: these are not really needed as the is the BAUDRATES etc. attribute...
+    # maybe i remove them before the final release...
+
+    def getSupportedBaudrates(self):
+        return [(str(b), b) for b in self.BAUDRATES]
+
+    def getSupportedByteSizes(self):
+        return [(str(b), b) for b in self.BYTESIZES]
+
+    def getSupportedStopbits(self):
+        return [(str(b), b) for b in self.STOPBITS]
+
+    def getSupportedParities(self):
+        return [(PARITY_NAMES[b], b) for b in self.PARITIES]
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def setPort(self, port):
+        """\
+        Change the port. The attribute portstr is set to a string that
+        contains the name of the port.
+        """
+
+        was_open = self._isOpen
+        if was_open: self.close()
+        if port is not None:
+            if isinstance(port, basestring):
+                self.portstr = port
+            else:
+                self.portstr = self.makeDeviceName(port)
+        else:
+            self.portstr = None
+        self._port = port
+        self.name = self.portstr
+        if was_open: self.open()
+
+    def getPort(self):
+        """\
+        Get the current port setting. The value that was passed on init or using
+        setPort() is passed back. See also the attribute portstr which contains
+        the name of the port as a string.
+        """
+        return self._port
+
+    port = property(getPort, setPort, doc="Port setting")
+
+
+    def setBaudrate(self, baudrate):
+        """\
+        Change baud rate. It raises a ValueError if the port is open and the
+        baud rate is not possible. If the port is closed, then the value is
+        accepted and the exception is raised when the port is opened.
+        """
+        try:
+            b = int(baudrate)
+        except TypeError:
+            raise ValueError("Not a valid baudrate: %r" % (baudrate,))
+        else:
+            if b <= 0:
+                raise ValueError("Not a valid baudrate: %r" % (baudrate,))
+            self._baudrate = b
+            if self._isOpen:  self._reconfigurePort()
+
+    def getBaudrate(self):
+        """Get the current baud rate setting."""
+        return self._baudrate
+
+    baudrate = property(getBaudrate, setBaudrate, doc="Baud rate setting")
+
+
+    def setByteSize(self, bytesize):
+        """Change byte size."""
+        if bytesize not in self.BYTESIZES: raise ValueError("Not a valid byte size: %r" % (bytesize,))
+        self._bytesize = bytesize
+        if self._isOpen: self._reconfigurePort()
+
+    def getByteSize(self):
+        """Get the current byte size setting."""
+        return self._bytesize
+
+    bytesize = property(getByteSize, setByteSize, doc="Byte size setting")
+
+
+    def setParity(self, parity):
+        """Change parity setting."""
+        if parity not in self.PARITIES: raise ValueError("Not a valid parity: %r" % (parity,))
+        self._parity = parity
+        if self._isOpen: self._reconfigurePort()
+
+    def getParity(self):
+        """Get the current parity setting."""
+        return self._parity
+
+    parity = property(getParity, setParity, doc="Parity setting")
+
+
+    def setStopbits(self, stopbits):
+        """Change stop bits size."""
+        if stopbits not in self.STOPBITS: raise ValueError("Not a valid stop bit size: %r" % (stopbits,))
+        self._stopbits = stopbits
+        if self._isOpen: self._reconfigurePort()
+
+    def getStopbits(self):
+        """Get the current stop bits setting."""
+        return self._stopbits
+
+    stopbits = property(getStopbits, setStopbits, doc="Stop bits setting")
+
+
+    def setTimeout(self, timeout):
+        """Change timeout setting."""
+        if timeout is not None:
+            try:
+                timeout + 1     # test if it's a number, will throw a TypeError if not...
+            except TypeError:
+                raise ValueError("Not a valid timeout: %r" % (timeout,))
+            if timeout < 0: raise ValueError("Not a valid timeout: %r" % (timeout,))
+        self._timeout = timeout
+        if self._isOpen: self._reconfigurePort()
+
+    def getTimeout(self):
+        """Get the current timeout setting."""
+        return self._timeout
+
+    timeout = property(getTimeout, setTimeout, doc="Timeout setting for read()")
+
+
+    def setWriteTimeout(self, timeout):
+        """Change timeout setting."""
+        if timeout is not None:
+            if timeout < 0: raise ValueError("Not a valid timeout: %r" % (timeout,))
+            try:
+                timeout + 1     #test if it's a number, will throw a TypeError if not...
+            except TypeError:
+                raise ValueError("Not a valid timeout: %r" % timeout)
+
+        self._writeTimeout = timeout
+        if self._isOpen: self._reconfigurePort()
+
+    def getWriteTimeout(self):
+        """Get the current timeout setting."""
+        return self._writeTimeout
+
+    writeTimeout = property(getWriteTimeout, setWriteTimeout, doc="Timeout setting for write()")
+
+
+    def setXonXoff(self, xonxoff):
+        """Change XON/XOFF setting."""
+        self._xonxoff = xonxoff
+        if self._isOpen: self._reconfigurePort()
+
+    def getXonXoff(self):
+        """Get the current XON/XOFF setting."""
+        return self._xonxoff
+
+    xonxoff = property(getXonXoff, setXonXoff, doc="XON/XOFF setting")
+
+    def setRtsCts(self, rtscts):
+        """Change RTS/CTS flow control setting."""
+        self._rtscts = rtscts
+        if self._isOpen: self._reconfigurePort()
+
+    def getRtsCts(self):
+        """Get the current RTS/CTS flow control setting."""
+        return self._rtscts
+
+    rtscts = property(getRtsCts, setRtsCts, doc="RTS/CTS flow control setting")
+
+    def setDsrDtr(self, dsrdtr=None):
+        """Change DsrDtr flow control setting."""
+        if dsrdtr is None:
+            # if not set, keep backwards compatibility and follow rtscts setting
+            self._dsrdtr = self._rtscts
+        else:
+            # if defined independently, follow its value
+            self._dsrdtr = dsrdtr
+        if self._isOpen: self._reconfigurePort()
+
+    def getDsrDtr(self):
+        """Get the current DSR/DTR flow control setting."""
+        return self._dsrdtr
+
+    dsrdtr = property(getDsrDtr, setDsrDtr, "DSR/DTR flow control setting")
+
+    def setInterCharTimeout(self, interCharTimeout):
+        """Change inter-character timeout setting."""
+        if interCharTimeout is not None:
+            if interCharTimeout < 0: raise ValueError("Not a valid timeout: %r" % interCharTimeout)
+            try:
+                interCharTimeout + 1     # test if it's a number, will throw a TypeError if not...
+            except TypeError:
+                raise ValueError("Not a valid timeout: %r" % interCharTimeout)
+
+        self._interCharTimeout = interCharTimeout
+        if self._isOpen: self._reconfigurePort()
+
+    def getInterCharTimeout(self):
+        """Get the current inter-character timeout setting."""
+        return self._interCharTimeout
+
+    interCharTimeout = property(getInterCharTimeout, setInterCharTimeout, doc="Inter-character timeout setting for read()")
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    _SETTINGS = ('baudrate', 'bytesize', 'parity', 'stopbits', 'xonxoff',
+            'dsrdtr', 'rtscts', 'timeout', 'writeTimeout', 'interCharTimeout')
+
+    def getSettingsDict(self):
+        """\
+        Get current port settings as a dictionary. For use with
+        applySettingsDict.
+        """
+        return dict([(key, getattr(self, '_'+key)) for key in self._SETTINGS])
+
+    def applySettingsDict(self, d):
+        """\
+        apply stored settings from a dictionary returned from
+        getSettingsDict. it's allowed to delete keys from the dictionary. these
+        values will simply left unchanged.
+        """
+        for key in self._SETTINGS:
+            if d[key] != getattr(self, '_'+key):   # check against internal "_" value
+                setattr(self, key, d[key])          # set non "_" value to use properties write function
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def __repr__(self):
+        """String representation of the current port settings and its state."""
+        return "%s<id=0x%x, open=%s>(port=%r, baudrate=%r, bytesize=%r, parity=%r, stopbits=%r, timeout=%r, xonxoff=%r, rtscts=%r, dsrdtr=%r)" % (
+            self.__class__.__name__,
+            id(self),
+            self._isOpen,
+            self.portstr,
+            self.baudrate,
+            self.bytesize,
+            self.parity,
+            self.stopbits,
+            self.timeout,
+            self.xonxoff,
+            self.rtscts,
+            self.dsrdtr,
+        )
+
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+    # compatibility with io library
+
+    def readable(self): return True
+    def writable(self): return True
+    def seekable(self): return False
+    def readinto(self, b):
+        data = self.read(len(b))
+        n = len(data)
+        try:
+            b[:n] = data
+        except TypeError, err:
+            import array
+            if not isinstance(b, array.array):
+                raise err
+            b[:n] = array.array('b', data)
+        return n
+
+
+if __name__ == '__main__':
+    import sys
+    s = SerialBase()
+    sys.stdout.write('port name:  %s\n' % s.portstr)
+    sys.stdout.write('baud rates: %s\n' % s.getSupportedBaudrates())
+    sys.stdout.write('byte sizes: %s\n' % s.getSupportedByteSizes())
+    sys.stdout.write('parities:   %s\n' % s.getSupportedParities())
+    sys.stdout.write('stop bits:  %s\n' % s.getSupportedStopbits())
+    sys.stdout.write('%s\n' % s)
diff --git a/scripts/serial/tools/__init__.py b/scripts/serial/tools/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/scripts/serial/tools/__init__.py
diff --git a/scripts/serial/tools/list_ports.py b/scripts/serial/tools/list_ports.py
new file mode 100644
index 0000000000..d373a5566d
--- /dev/null
+++ b/scripts/serial/tools/list_ports.py
@@ -0,0 +1,103 @@
+#!/usr/bin/env python
+
+# portable serial port access with python
+# this is a wrapper module for different platform implementations of the
+# port enumeration feature
+#
+# (C) 2011-2013 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+"""\
+This module will provide a function called comports that returns an
+iterable (generator or list) that will enumerate available com ports. Note that
+on some systems non-existent ports may be listed.
+
+Additionally a grep function is supplied that can be used to search for ports
+based on their descriptions or hardware ID.
+"""
+
+import sys, os, re
+
+# chose an implementation, depending on os
+#~ if sys.platform == 'cli':
+#~ else:
+import os
+# chose an implementation, depending on os
+if os.name == 'nt': #sys.platform == 'win32':
+    from serial.tools.list_ports_windows import *
+elif os.name == 'posix':
+    from serial.tools.list_ports_posix import *
+#~ elif os.name == 'java':
+else:
+    raise ImportError("Sorry: no implementation for your platform ('%s') available" % (os.name,))
+
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+def grep(regexp):
+    """\
+    Search for ports using a regular expression. Port name, description and
+    hardware ID are searched. The function returns an iterable that returns the
+    same tuples as comport() would do.
+    """
+    r = re.compile(regexp, re.I)
+    for port, desc, hwid in comports():
+        if r.search(port) or r.search(desc) or r.search(hwid):
+            yield port, desc, hwid
+
+
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+def main():
+    import optparse
+
+    parser = optparse.OptionParser(
+        usage = "%prog [options] [<regexp>]",
+        description = "Miniterm - A simple terminal program for the serial port."
+    )
+
+    parser.add_option("--debug",
+            help="print debug messages and tracebacks (development mode)",
+            dest="debug",
+            default=False,
+            action='store_true')
+
+    parser.add_option("-v", "--verbose",
+            help="show more messages (can be given multiple times)",
+            dest="verbose",
+            default=1,
+            action='count')
+
+    parser.add_option("-q", "--quiet",
+            help="suppress all messages",
+            dest="verbose",
+            action='store_const',
+            const=0)
+
+    (options, args) = parser.parse_args()
+
+
+    hits = 0
+    # get iteraror w/ or w/o filter
+    if args:
+        if len(args) > 1:
+            parser.error('more than one regexp not supported')
+        print "Filtered list with regexp: %r" % (args[0],)
+        iterator = sorted(grep(args[0]))
+    else:
+        iterator = sorted(comports())
+    # list them
+    for port, desc, hwid in iterator:
+        print("%-20s" % (port,))
+        if options.verbose > 1:
+            print("    desc: %s" % (desc,))
+            print("    hwid: %s" % (hwid,))
+        hits += 1
+    if options.verbose:
+        if hits:
+            print("%d ports found" % (hits,))
+        else:
+            print("no ports found")
+
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+# test
+if __name__ == '__main__':
+    main()
diff --git a/scripts/serial/tools/list_ports_linux.py b/scripts/serial/tools/list_ports_linux.py
new file mode 100644
index 0000000000..955761eaa4
--- /dev/null
+++ b/scripts/serial/tools/list_ports_linux.py
@@ -0,0 +1,152 @@
+#!/usr/bin/env python

+

+# portable serial port access with python

+#

+# This is a module that gathers a list of serial ports including details on

+# GNU/Linux systems

+#

+# (C) 2011-2013 Chris Liechti <cliechti@gmx.net>

+# this is distributed under a free software license, see license.txt

+

+import glob

+import sys

+import os

+import re

+

+try:

+    import subprocess

+except ImportError:

+    def popen(argv):

+        try:

+            si, so =  os.popen4(' '.join(argv))

+            return so.read().strip()

+        except:

+            raise IOError('lsusb failed')

+else:

+    def popen(argv):

+        try:

+            return subprocess.check_output(argv, stderr=subprocess.STDOUT).strip()

+        except:

+            raise IOError('lsusb failed')

+

+

+# The comports function is expected to return an iterable that yields tuples of

+# 3 strings: port name, human readable description and a hardware ID.

+#

+# as currently no method is known to get the second two strings easily, they

+# are currently just identical to the port name.

+

+# try to detect the OS so that a device can be selected...

+plat = sys.platform.lower()

+

+def read_line(filename):

+    """\

+    Helper function to read a single line from a file.

+    Returns None on errors..

+    """

+    try:

+        f = open(filename)

+        line = f.readline().strip()

+        f.close()

+        return line

+    except IOError:

+        return None

+

+def re_group(regexp, text):

+    """search for regexp in text, return 1st group on match"""

+    if sys.version < '3':

+        m = re.search(regexp, text)

+    else:

+        # text is bytes-like

+        m = re.search(regexp, text.decode('ascii', 'replace'))

+    if m: return m.group(1)

+

+

+# try to extract descriptions from sysfs. this was done by experimenting,

+# no guarantee that it works for all devices or in the future...

+

+def usb_sysfs_hw_string(sysfs_path):

+    """given a path to a usb device in sysfs, return a string describing it"""

+    bus, dev = os.path.basename(os.path.realpath(sysfs_path)).split('-')

+    snr = read_line(sysfs_path+'/serial')

+    if snr:

+        snr_txt = ' SNR=%s' % (snr,)

+    else:

+        snr_txt = ''

+    return 'USB VID:PID=%s:%s%s' % (

+            read_line(sysfs_path+'/idVendor'),

+            read_line(sysfs_path+'/idProduct'),

+            snr_txt

+            )

+

+def usb_lsusb_string(sysfs_path):

+    base = os.path.basename(os.path.realpath(sysfs_path))

+    bus = base.split('-')[0]

+    try:

+        dev = int(read_line(os.path.join(sysfs_path, 'devnum')))

+        desc = popen(['lsusb', '-v', '-s', '%s:%s' % (bus, dev)])

+        # descriptions from device

+        iManufacturer = re_group('iManufacturer\s+\w+ (.+)', desc)

+        iProduct = re_group('iProduct\s+\w+ (.+)', desc)

+        iSerial = re_group('iSerial\s+\w+ (.+)', desc) or ''

+        # descriptions from kernel

+        idVendor = re_group('idVendor\s+0x\w+ (.+)', desc)

+        idProduct = re_group('idProduct\s+0x\w+ (.+)', desc)

+        # create descriptions. prefer text from device, fall back to the others

+        return '%s %s %s' % (iManufacturer or idVendor, iProduct or idProduct, iSerial)

+    except IOError:

+        return base

+

+def describe(device):

+    """\

+    Get a human readable description.

+    For USB-Serial devices try to run lsusb to get a human readable description.

+    For USB-CDC devices read the description from sysfs.

+    """

+    base = os.path.basename(device)

+    # USB-Serial devices

+    sys_dev_path = '/sys/class/tty/%s/device/driver/%s' % (base, base)

+    if os.path.exists(sys_dev_path):

+        sys_usb = os.path.dirname(os.path.dirname(os.path.realpath(sys_dev_path)))

+        return usb_lsusb_string(sys_usb)

+    # USB-CDC devices

+    sys_dev_path = '/sys/class/tty/%s/device/interface' % (base,)

+    if os.path.exists(sys_dev_path):

+        return read_line(sys_dev_path)

+    # USB Product Information

+    sys_dev_path = '/sys/class/tty/%s/device' % (base,)

+    if os.path.exists(sys_dev_path):

+        product_name_file = os.path.dirname(os.path.realpath(sys_dev_path)) + "/product"

+        if os.path.exists(product_name_file):

+            return read_line(product_name_file)

+    return base

+

+def hwinfo(device):

+    """Try to get a HW identification using sysfs"""

+    base = os.path.basename(device)

+    if os.path.exists('/sys/class/tty/%s/device' % (base,)):

+        # PCI based devices

+        sys_id_path = '/sys/class/tty/%s/device/id' % (base,)

+        if os.path.exists(sys_id_path):

+            return read_line(sys_id_path)

+        # USB-Serial devices

+        sys_dev_path = '/sys/class/tty/%s/device/driver/%s' % (base, base)

+        if os.path.exists(sys_dev_path):

+            sys_usb = os.path.dirname(os.path.dirname(os.path.realpath(sys_dev_path)))

+            return usb_sysfs_hw_string(sys_usb)

+        # USB-CDC devices

+        if base.startswith('ttyACM'):

+            sys_dev_path = '/sys/class/tty/%s/device' % (base,)

+            if os.path.exists(sys_dev_path):

+                return usb_sysfs_hw_string(sys_dev_path + '/..')

+    return 'n/a'    # XXX directly remove these from the list?

+

+def comports():

+    devices = glob.glob('/dev/ttyS*') + glob.glob('/dev/ttyUSB*') + glob.glob('/dev/ttyACM*')

+    return [(d, describe(d), hwinfo(d)) for d in devices]

+

+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

+# test

+if __name__ == '__main__':

+    for port, desc, hwid in sorted(comports()):

+        print "%s: %s [%s]" % (port, desc, hwid)

diff --git a/scripts/serial/urlhandler/__init__.py b/scripts/serial/urlhandler/__init__.py
new file mode 100644
index 0000000000..e69de29bb2
--- /dev/null
+++ b/scripts/serial/urlhandler/__init__.py
diff --git a/scripts/serial/urlhandler/protocol_hwgrep.py b/scripts/serial/urlhandler/protocol_hwgrep.py
new file mode 100644
index 0000000000..62cda43aa7
--- /dev/null
+++ b/scripts/serial/urlhandler/protocol_hwgrep.py
@@ -0,0 +1,45 @@
+#! python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see __init__.py
+#
+# This module implements a special URL handler that uses the port listing to
+# find ports by searching the string descriptions.
+#
+# (C) 2011 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+#
+# URL format:    hwgrep://regexp
+
+import serial
+import serial.tools.list_ports
+
+class Serial(serial.Serial):
+    """Just inherit the native Serial port implementation and patch the open function."""
+
+    def setPort(self, value):
+        """translate port name before storing it"""
+        if isinstance(value, basestring) and value.startswith('hwgrep://'):
+            serial.Serial.setPort(self, self.fromURL(value))
+        else:
+            serial.Serial.setPort(self, value)
+
+    def fromURL(self, url):
+        """extract host and port from an URL string"""
+        if url.lower().startswith("hwgrep://"): url = url[9:]
+        # use a for loop to get the 1st element from the generator
+        for port, desc, hwid in serial.tools.list_ports.grep(url):
+            return port
+        else:
+            raise serial.SerialException('no ports found matching regexp %r' % (url,))
+
+    # override property
+    port = property(serial.Serial.getPort, setPort, doc="Port setting")
+
+# - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+if __name__ == '__main__':
+    #~ s = Serial('hwgrep://ttyS0')
+    s = Serial(None)
+    s.port = 'hwgrep://ttyS0'
+    print s
+
diff --git a/scripts/serial/urlhandler/protocol_loop.py b/scripts/serial/urlhandler/protocol_loop.py
new file mode 100644
index 0000000000..a414839761
--- /dev/null
+++ b/scripts/serial/urlhandler/protocol_loop.py
@@ -0,0 +1,279 @@
+#! python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see __init__.py
+#
+# This module implements a loop back connection receiving itself what it sent.
+#
+# The purpose of this module is.. well... You can run the unit tests with it.
+# and it was so easy to implement ;-)
+#
+# (C) 2001-2011 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+#
+# URL format:    loop://[option[/option...]]
+# options:
+# - "debug" print diagnostic messages
+
+from serial.serialutil import *
+import threading
+import time
+import logging
+
+# map log level names to constants. used in fromURL()
+LOGGER_LEVELS = {
+    'debug': logging.DEBUG,
+    'info': logging.INFO,
+    'warning': logging.WARNING,
+    'error': logging.ERROR,
+    }
+
+
+class LoopbackSerial(SerialBase):
+    """Serial port implementation that simulates a loop back connection in plain software."""
+
+    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+                 9600, 19200, 38400, 57600, 115200)
+
+    def open(self):
+        """\
+        Open port with current settings. This may throw a SerialException
+        if the port cannot be opened.
+        """
+        if self._isOpen:
+            raise SerialException("Port is already open.")
+        self.logger = None
+        self.buffer_lock = threading.Lock()
+        self.loop_buffer = bytearray()
+        self.cts = False
+        self.dsr = False
+
+        if self._port is None:
+            raise SerialException("Port must be configured before it can be used.")
+        # not that there is anything to open, but the function applies the
+        # options found in the URL
+        self.fromURL(self.port)
+
+        # not that there anything to configure...
+        self._reconfigurePort()
+        # all things set up get, now a clean start
+        self._isOpen = True
+        if not self._rtscts:
+            self.setRTS(True)
+            self.setDTR(True)
+        self.flushInput()
+        self.flushOutput()
+
+    def _reconfigurePort(self):
+        """\
+        Set communication parameters on opened port. For the loop://
+        protocol all settings are ignored!
+        """
+        # not that's it of any real use, but it helps in the unit tests
+        if not isinstance(self._baudrate, (int, long)) or not 0 < self._baudrate < 2**32:
+            raise ValueError("invalid baudrate: %r" % (self._baudrate))
+        if self.logger:
+            self.logger.info('_reconfigurePort()')
+
+    def close(self):
+        """Close port"""
+        if self._isOpen:
+            self._isOpen = False
+            # in case of quick reconnects, give the server some time
+            time.sleep(0.3)
+
+    def makeDeviceName(self, port):
+        raise SerialException("there is no sensible way to turn numbers into URLs")
+
+    def fromURL(self, url):
+        """extract host and port from an URL string"""
+        if url.lower().startswith("loop://"): url = url[7:]
+        try:
+            # process options now, directly altering self
+            for option in url.split('/'):
+                if '=' in option:
+                    option, value = option.split('=', 1)
+                else:
+                    value = None
+                if not option:
+                    pass
+                elif option == 'logging':
+                    logging.basicConfig()   # XXX is that good to call it here?
+                    self.logger = logging.getLogger('pySerial.loop')
+                    self.logger.setLevel(LOGGER_LEVELS[value])
+                    self.logger.debug('enabled logging')
+                else:
+                    raise ValueError('unknown option: %r' % (option,))
+        except ValueError, e:
+            raise SerialException('expected a string in the form "[loop://][option[/option...]]": %s' % e)
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def inWaiting(self):
+        """Return the number of characters currently in the input buffer."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            # attention the logged value can differ from return value in
+            # threaded environments...
+            self.logger.debug('inWaiting() -> %d' % (len(self.loop_buffer),))
+        return len(self.loop_buffer)
+
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self._timeout is not None:
+            timeout = time.time() + self._timeout
+        else:
+            timeout = None
+        data = bytearray()
+        while size > 0:
+            self.buffer_lock.acquire()
+            try:
+                block = to_bytes(self.loop_buffer[:size])
+                del self.loop_buffer[:size]
+            finally:
+                self.buffer_lock.release()
+            data += block
+            size -= len(block)
+            # check for timeout now, after data has been read.
+            # useful for timeout = 0 (non blocking) read
+            if timeout and time.time() > timeout:
+                break
+        return bytes(data)
+
+    def write(self, data):
+        """\
+        Output the given string over the serial port. Can block if the
+        connection is blocked. May raise SerialException if the connection is
+        closed.
+        """
+        if not self._isOpen: raise portNotOpenError
+        # ensure we're working with bytes
+        data = to_bytes(data)
+        # calculate aprox time that would be used to send the data
+        time_used_to_send = 10.0*len(data) / self._baudrate
+        # when a write timeout is configured check if we would be successful
+        # (not sending anything, not even the part that would have time)
+        if self._writeTimeout is not None and time_used_to_send > self._writeTimeout:
+            time.sleep(self._writeTimeout) # must wait so that unit test succeeds
+            raise writeTimeoutError
+        self.buffer_lock.acquire()
+        try:
+            self.loop_buffer += data
+        finally:
+            self.buffer_lock.release()
+        return len(data)
+
+    def flushInput(self):
+        """Clear input buffer, discarding all that is in the buffer."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('flushInput()')
+        self.buffer_lock.acquire()
+        try:
+            del self.loop_buffer[:]
+        finally:
+            self.buffer_lock.release()
+
+    def flushOutput(self):
+        """\
+        Clear output buffer, aborting the current output and
+        discarding all that is in the buffer.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('flushOutput()')
+
+    def sendBreak(self, duration=0.25):
+        """\
+        Send break condition. Timed, returns to idle state after given
+        duration.
+        """
+        if not self._isOpen: raise portNotOpenError
+
+    def setBreak(self, level=True):
+        """\
+        Set break: Controls TXD. When active, to transmitting is
+        possible.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('setBreak(%r)' % (level,))
+
+    def setRTS(self, level=True):
+        """Set terminal status line: Request To Send"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('setRTS(%r) -> state of CTS' % (level,))
+        self.cts = level
+
+    def setDTR(self, level=True):
+        """Set terminal status line: Data Terminal Ready"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('setDTR(%r) -> state of DSR' % (level,))
+        self.dsr = level
+
+    def getCTS(self):
+        """Read terminal status line: Clear To Send"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('getCTS() -> state of RTS (%r)' % (self.cts,))
+        return self.cts
+
+    def getDSR(self):
+        """Read terminal status line: Data Set Ready"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('getDSR() -> state of DTR (%r)' % (self.dsr,))
+        return self.dsr
+
+    def getRI(self):
+        """Read terminal status line: Ring Indicator"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getRI()')
+        return False
+
+    def getCD(self):
+        """Read terminal status line: Carrier Detect"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getCD()')
+        return True
+
+    # - - - platform specific - - -
+    # None so far
+
+
+# assemble Serial class with the platform specific implementation and the base
+# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
+# library, derive from io.RawIOBase
+try:
+    import io
+except ImportError:
+    # classic version with our own file-like emulation
+    class Serial(LoopbackSerial, FileLike):
+        pass
+else:
+    # io library present
+    class Serial(LoopbackSerial, io.RawIOBase):
+        pass
+
+
+# simple client test
+if __name__ == '__main__':
+    import sys
+    s = Serial('loop://')
+    sys.stdout.write('%s\n' % s)
+
+    sys.stdout.write("write...\n")
+    s.write("hello\n")
+    s.flush()
+    sys.stdout.write("read: %s\n" % s.read(5))
+
+    s.close()
diff --git a/scripts/serial/urlhandler/protocol_rfc2217.py b/scripts/serial/urlhandler/protocol_rfc2217.py
new file mode 100644
index 0000000000..981ba45fea
--- /dev/null
+++ b/scripts/serial/urlhandler/protocol_rfc2217.py
@@ -0,0 +1,11 @@
+#! python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see ../__init__.py
+#
+# This is a thin wrapper to load the rfc2271 implementation.
+#
+# (C) 2011 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+
+from serial.rfc2217 import Serial
diff --git a/scripts/serial/urlhandler/protocol_socket.py b/scripts/serial/urlhandler/protocol_socket.py
new file mode 100644
index 0000000000..dc5992342c
--- /dev/null
+++ b/scripts/serial/urlhandler/protocol_socket.py
@@ -0,0 +1,291 @@
+#! python
+#
+# Python Serial Port Extension for Win32, Linux, BSD, Jython
+# see __init__.py
+#
+# This module implements a simple socket based client.
+# It does not support changing any port parameters and will silently ignore any
+# requests to do so.
+#
+# The purpose of this module is that applications using pySerial can connect to
+# TCP/IP to serial port converters that do not support RFC 2217.
+#
+# (C) 2001-2011 Chris Liechti <cliechti@gmx.net>
+# this is distributed under a free software license, see license.txt
+#
+# URL format:    socket://<host>:<port>[/option[/option...]]
+# options:
+# - "debug" print diagnostic messages
+
+from serial.serialutil import *
+import time
+import socket
+import select
+import logging
+
+# map log level names to constants. used in fromURL()
+LOGGER_LEVELS = {
+    'debug': logging.DEBUG,
+    'info': logging.INFO,
+    'warning': logging.WARNING,
+    'error': logging.ERROR,
+    }
+
+POLL_TIMEOUT = 2
+
+class SocketSerial(SerialBase):
+    """Serial port implementation for plain sockets."""
+
+    BAUDRATES = (50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800,
+                 9600, 19200, 38400, 57600, 115200)
+
+    def open(self):
+        """\
+        Open port with current settings. This may throw a SerialException
+        if the port cannot be opened.
+        """
+        self.logger = None
+        if self._port is None:
+            raise SerialException("Port must be configured before it can be used.")
+        if self._isOpen:
+            raise SerialException("Port is already open.")
+        try:
+            # XXX in future replace with create_connection (py >=2.6)
+            self._socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+            self._socket.connect(self.fromURL(self.portstr))
+        except Exception, msg:
+            self._socket = None
+            raise SerialException("Could not open port %s: %s" % (self.portstr, msg))
+
+        self._socket.settimeout(POLL_TIMEOUT) # used for write timeout support :/
+
+        # not that there anything to configure...
+        self._reconfigurePort()
+        # all things set up get, now a clean start
+        self._isOpen = True
+        if not self._rtscts:
+            self.setRTS(True)
+            self.setDTR(True)
+        self.flushInput()
+        self.flushOutput()
+
+    def _reconfigurePort(self):
+        """\
+        Set communication parameters on opened port. For the socket://
+        protocol all settings are ignored!
+        """
+        if self._socket is None:
+            raise SerialException("Can only operate on open ports")
+        if self.logger:
+            self.logger.info('ignored port configuration change')
+
+    def close(self):
+        """Close port"""
+        if self._isOpen:
+            if self._socket:
+                try:
+                    self._socket.shutdown(socket.SHUT_RDWR)
+                    self._socket.close()
+                except:
+                    # ignore errors.
+                    pass
+                self._socket = None
+            self._isOpen = False
+            # in case of quick reconnects, give the server some time
+            time.sleep(0.3)
+
+    def makeDeviceName(self, port):
+        raise SerialException("there is no sensible way to turn numbers into URLs")
+
+    def fromURL(self, url):
+        """extract host and port from an URL string"""
+        if url.lower().startswith("socket://"): url = url[9:]
+        try:
+            # is there a "path" (our options)?
+            if '/' in url:
+                # cut away options
+                url, options = url.split('/', 1)
+                # process options now, directly altering self
+                for option in options.split('/'):
+                    if '=' in option:
+                        option, value = option.split('=', 1)
+                    else:
+                        value = None
+                    if option == 'logging':
+                        logging.basicConfig()   # XXX is that good to call it here?
+                        self.logger = logging.getLogger('pySerial.socket')
+                        self.logger.setLevel(LOGGER_LEVELS[value])
+                        self.logger.debug('enabled logging')
+                    else:
+                        raise ValueError('unknown option: %r' % (option,))
+            # get host and port
+            host, port = url.split(':', 1) # may raise ValueError because of unpacking
+            port = int(port)               # and this if it's not a number
+            if not 0 <= port < 65536: raise ValueError("port not in range 0...65535")
+        except ValueError, e:
+            raise SerialException('expected a string in the form "[rfc2217://]<host>:<port>[/option[/option...]]": %s' % e)
+        return (host, port)
+
+    #  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -  -
+
+    def inWaiting(self):
+        """Return the number of characters currently in the input buffer."""
+        if not self._isOpen: raise portNotOpenError
+        # Poll the socket to see if it is ready for reading.
+        # If ready, at least one byte will be to read.
+        lr, lw, lx = select.select([self._socket], [], [], 0)
+        return len(lr)
+
+    def read(self, size=1):
+        """\
+        Read size bytes from the serial port. If a timeout is set it may
+        return less characters as requested. With no timeout it will block
+        until the requested number of bytes is read.
+        """
+        if not self._isOpen: raise portNotOpenError
+        data = bytearray()
+        if self._timeout is not None:
+            timeout = time.time() + self._timeout
+        else:
+            timeout = None
+        while len(data) < size and (timeout is None or time.time() < timeout):
+            try:
+                # an implementation with internal buffer would be better
+                # performing...
+                t = time.time()
+                block = self._socket.recv(size - len(data))
+                duration = time.time() - t
+                if block:
+                    data.extend(block)
+                else:
+                    # no data -> EOF (connection probably closed)
+                    break
+            except socket.timeout:
+                # just need to get out of recv from time to time to check if
+                # still alive
+                continue
+            except socket.error, e:
+                # connection fails -> terminate loop
+                raise SerialException('connection failed (%s)' % e)
+        return bytes(data)
+
+    def write(self, data):
+        """\
+        Output the given string over the serial port. Can block if the
+        connection is blocked. May raise SerialException if the connection is
+        closed.
+        """
+        if not self._isOpen: raise portNotOpenError
+        try:
+            self._socket.sendall(to_bytes(data))
+        except socket.error, e:
+            # XXX what exception if socket connection fails
+            raise SerialException("socket connection failed: %s" % e)
+        return len(data)
+
+    def flushInput(self):
+        """Clear input buffer, discarding all that is in the buffer."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored flushInput')
+
+    def flushOutput(self):
+        """\
+        Clear output buffer, aborting the current output and
+        discarding all that is in the buffer.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored flushOutput')
+
+    def sendBreak(self, duration=0.25):
+        """\
+        Send break condition. Timed, returns to idle state after given
+        duration.
+        """
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored sendBreak(%r)' % (duration,))
+
+    def setBreak(self, level=True):
+        """Set break: Controls TXD. When active, to transmitting is
+        possible."""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored setBreak(%r)' % (level,))
+
+    def setRTS(self, level=True):
+        """Set terminal status line: Request To Send"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored setRTS(%r)' % (level,))
+
+    def setDTR(self, level=True):
+        """Set terminal status line: Data Terminal Ready"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('ignored setDTR(%r)' % (level,))
+
+    def getCTS(self):
+        """Read terminal status line: Clear To Send"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getCTS()')
+        return True
+
+    def getDSR(self):
+        """Read terminal status line: Data Set Ready"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getDSR()')
+        return True
+
+    def getRI(self):
+        """Read terminal status line: Ring Indicator"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getRI()')
+        return False
+
+    def getCD(self):
+        """Read terminal status line: Carrier Detect"""
+        if not self._isOpen: raise portNotOpenError
+        if self.logger:
+            self.logger.info('returning dummy for getCD()')
+        return True
+
+    # - - - platform specific - - -
+
+    # works on Linux and probably all the other POSIX systems
+    def fileno(self):
+        """Get the file handle of the underlying socket for use with select"""
+        return self._socket.fileno()
+
+
+# assemble Serial class with the platform specific implementation and the base
+# for file-like behavior. for Python 2.6 and newer, that provide the new I/O
+# library, derive from io.RawIOBase
+try:
+    import io
+except ImportError:
+    # classic version with our own file-like emulation
+    class Serial(SocketSerial, FileLike):
+        pass
+else:
+    # io library present
+    class Serial(SocketSerial, io.RawIOBase):
+        pass
+
+
+# simple client test
+if __name__ == '__main__':
+    import sys
+    s = Serial('socket://localhost:7000')
+    sys.stdout.write('%s\n' % s)
+
+    sys.stdout.write("write...\n")
+    s.write("hello\n")
+    s.flush()
+    sys.stdout.write("read: %s\n" % s.read(5))
+
+    s.close()