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-rw-r--r--mux.c397
1 files changed, 256 insertions, 141 deletions
diff --git a/mux.c b/mux.c
index 0f4ad47..1cfb914 100644
--- a/mux.c
+++ b/mux.c
@@ -20,165 +20,190 @@
#include "microcom.h"
#include <arpa/telnet.h>
#include <arpa/inet.h>
+#include <stdbool.h>
#define BUFSIZE 1024
-static int do_com_port_option(unsigned char *buf, int len)
+/* This is called with buf[-2:0] being IAC SB COM_PORT_OPTION */
+static int do_com_port_option(struct ios_ops *ios, unsigned char *buf, int len)
{
- int i = 0;
+ int i = 2;
+
+ switch (buf[1]) {
+ case SET_BAUDRATE_CS:
+ dbg_printf("SET_BAUDRATE_CS ");
+ break;
+ case SET_DATASIZE_CS:
+ dbg_printf("SET_DATASIZE_CS ");
+ break;
+ case SET_PARITY_CS:
+ dbg_printf("SET_PARITY_CS ");
+ break;
+ case SET_STOPSIZE_CS:
+ dbg_printf("SET_STOPSIZE_CS ");
+ break;
+ case SET_CONTROL_CS:
+ dbg_printf("SET_CONTROL_CS ");
+ break;
+ case NOTIFY_LINESTATE_CS:
+ dbg_printf("NOTIFY_LINESTATE_CS ");
+ break;
+ case NOTIFY_MODEMSTATE_CS:
+ dbg_printf("NOTIFY_MODEMSTATE_CS ");
+ break;
+ case FLOWCONTROL_SUSPEND_CS:
+ dbg_printf("FLOWCONTROL_SUSPEND_CS ");
+ break;
+ case FLOWCONTROL_RESUME_CS:
+ dbg_printf("FLOWCONTROL_RESUME_CS ");
+ break;
+ case SET_LINESTATE_MASK_CS:
+ dbg_printf("SET_LINESTATE_MASK_CS ");
+ break;
+ case SET_MODEMSTATE_MASK_CS:
+ dbg_printf("SET_MODEMSTATE_MASK_CS ");
+ break;
+ case PURGE_DATA_CS:
+ dbg_printf("PURGE_DATA_CS ");
+ break;
+ case SET_BAUDRATE_SC:
+ dbg_printf("SET_BAUDRATE_SC %d ",
+ buf[2] << 24 | buf[3] << 16 | buf[4] << 8 | buf[5]);
+ i += 4;
+ break;
+ case SET_DATASIZE_SC:
+ dbg_printf("SET_DATASIZE_SC ");
+ break;
+ case SET_PARITY_SC:
+ dbg_printf("SET_PARITY_SC ");
+ break;
+ case SET_STOPSIZE_SC:
+ dbg_printf("SET_STOPSIZE_SC ");
+ break;
+ case SET_CONTROL_SC:
+ i++;
+ dbg_printf("SET_CONTROL_SC 0x%02x ", buf[i]);
+ break;
+ case NOTIFY_LINESTATE_SC:
+ dbg_printf("NOTIFY_LINESTATE_SC ");
+ break;
+ case NOTIFY_MODEMSTATE_SC:
+ i++;
+ dbg_printf("NOTIFY_MODEMSTATE_SC 0x%02x ", buf[i]);
+ break;
+ case FLOWCONTROL_SUSPEND_SC:
+ dbg_printf("FLOWCONTROL_SUSPEND_SC ");
+ break;
+ case FLOWCONTROL_RESUME_SC:
+ dbg_printf("FLOWCONTROL_RESUME_SC ");
+ break;
+ case SET_LINESTATE_MASK_SC:
+ dbg_printf("SET_LINESTATE_MASK_SC ");
+ break;
+ case SET_MODEMSTATE_MASK_SC:
+ dbg_printf("SET_MODEMSTATE_MASK_SC ");
+ break;
+ case PURGE_DATA_SC:
+ dbg_printf("PURGE_DATA_SC ");
+ break;
+ default:
+ dbg_printf("??? %d ", buf[i]);
+ break;
+ }
while (i < len) {
- switch (buf[i]) {
- case IAC:
- dbg_printf("IAC ");
- return i + 1;
- case SET_BAUDRATE_CS:
- dbg_printf("SET_BAUDRATE_CS ");
- break;
- case SET_DATASIZE_CS:
- dbg_printf("SET_DATASIZE_CS ");
- break;
- case SET_PARITY_CS:
- dbg_printf("SET_PARITY_CS ");
- break;
- case SET_STOPSIZE_CS:
- dbg_printf("SET_STOPSIZE_CS ");
- break;
- case SET_CONTROL_CS:
- dbg_printf("SET_CONTROL_CS ");
- break;
- case NOTIFY_LINESTATE_CS:
- dbg_printf("NOTIFY_LINESTATE_CS ");
- break;
- case NOTIFY_MODEMSTATE_CS:
- dbg_printf("NOTIFY_MODEMSTATE_CS ");
- break;
- case FLOWCONTROL_SUSPEND_CS:
- dbg_printf("FLOWCONTROL_SUSPEND_CS ");
- break;
- case FLOWCONTROL_RESUME_CS:
- dbg_printf("FLOWCONTROL_RESUME_CS ");
- break;
- case SET_LINESTATE_MASK_CS:
- dbg_printf("SET_LINESTATE_MASK_CS ");
- break;
- case SET_MODEMSTATE_MASK_CS:
- dbg_printf("SET_MODEMSTATE_MASK_CS ");
- break;
- case PURGE_DATA_CS:
- dbg_printf("PURGE_DATA_CS ");
- break;
- case SET_BAUDRATE_SC:
- dbg_printf("SET_BAUDRATE_SC %d ", ntohl(*(int *)&buf[i + 1]));
- i += 4;
- break;
- case SET_DATASIZE_SC:
- dbg_printf("SET_DATASIZE_SC ");
- break;
- case SET_PARITY_SC:
- dbg_printf("SET_PARITY_SC ");
- break;
- case SET_STOPSIZE_SC:
- dbg_printf("SET_STOPSIZE_SC ");
- break;
- case SET_CONTROL_SC:
- i++;
- dbg_printf("SET_CONTROL_SC 0x%02x ", buf[i]);
- break;
- case NOTIFY_LINESTATE_SC:
- dbg_printf("NOTIFY_LINESTATE_SC ");
- break;
- case NOTIFY_MODEMSTATE_SC:
- i++;
- dbg_printf("NOTIFY_MODEMSTATE_SC 0x%02x ", buf[i]);
- break;
- case FLOWCONTROL_SUSPEND_SC:
- dbg_printf("FLOWCONTROL_SUSPEND_SC ");
- break;
- case FLOWCONTROL_RESUME_SC:
- dbg_printf("FLOWCONTROL_RESUME_SC ");
- break;
- case SET_LINESTATE_MASK_SC:
- dbg_printf("SET_LINESTATE_MASK_SC ");
- break;
- case SET_MODEMSTATE_MASK_SC:
- dbg_printf("SET_MODEMSTATE_MASK_SC ");
- break;
- case PURGE_DATA_SC:
- dbg_printf("PURGE_DATA_SC ");
- break;
- default:
- dbg_printf("%d ", buf[i]);
- break;
+ if (buf[i] == IAC) {
+ if (i + 1 < len && buf[i+1] == IAC) {
+ /* quoted IAC -> unquote */
+ ++i;
+ } else if (i + 1 < len && buf[i+1] == SE) {
+ dbg_printf("IAC SE\n");
+ return i + 2;
+ }
}
- i++;
+ dbg_printf("%d ", buf[i]);
+
+ ++i;
}
- return len;
+ fprintf(stderr, "Incomplete SB string\n");
+ return -EINVAL;
}
-static int do_subneg(unsigned char *buf, int len)
+struct telnet_option {
+ unsigned char id;
+ const char *name;
+ int (*subneg_handler)(struct ios_ops *ios, unsigned char *buf, int len);
+ bool sent_will;
+};
+
+#define TELNET_OPTION(x) .id = TELNET_OPTION_ ## x, .name = #x
+
+static const struct telnet_option telnet_options[] = {
+ {
+ TELNET_OPTION(COM_PORT_CONTROL),
+ .subneg_handler = do_com_port_option,
+ .sent_will = true,
+ }, {
+ TELNET_OPTION(BINARY_TRANSMISSION),
+ }, {
+ TELNET_OPTION(ECHO),
+ }, {
+ TELNET_OPTION(SUPPRESS_GO_AHEAD),
+ }
+};
+
+static const struct telnet_option *get_telnet_option(unsigned char id)
{
- int i = 0;
+ int i;
- while (i < len) {
- switch (buf[i]) {
- case COM_PORT_OPTION:
- dbg_printf("COM_PORT_OPTION ");
- return do_com_port_option(&buf[i + 1], len - i) + 1;
- case IAC:
- dbg_printf("IAC ");
- return len - i;
- default:
- dbg_printf("%d ", buf[i]);
- break;
- }
- i++;
+ for (i = 0; i < ARRAY_SIZE(telnet_options); ++i) {
+ if (id == telnet_options[i].id)
+ return &telnet_options[i];
}
- return len;
+ return NULL;
}
-static int handle_command(unsigned char *buf, int len)
+
+/* This function is called with buf[-2:-1] being IAC SB */
+static int do_subneg(struct ios_ops *ios, unsigned char *buf, int len)
{
- int i = 0;
+ const struct telnet_option *option = get_telnet_option(buf[0]);
+
+ if (option)
+ dbg_printf("%s ", option->name);
+ if (option->subneg_handler) {
+ return option->subneg_handler(ios, buf, len);
+ } else {
+ /* skip over subneg string */
+ int i;
+ for (i = 0; i < len - 1; ++i) {
+ if (buf[i] != IAC) {
+ dbg_printf("%d ", buf[i]);
+ continue;
+ }
- while (i < len) {
- switch (buf[i]) {
- case SB:
- dbg_printf("SB ");
- i += do_subneg(&buf[i+1], len - i);
- break;
- case IAC:
- dbg_printf("IAC ");
- break;
- case COM_PORT_OPTION:
- dbg_printf("COM_PORT_OPTION ");
- break;
- case SE:
- dbg_printf("SE ");
- break;
- case WILL:
- dbg_printf("WILL ");
- break;
- case WONT:
- dbg_printf("WONT ");
- break;
- case DO:
- dbg_printf("DO ");
- break;
- case DONT:
- dbg_printf("DONT ");
- break;
- default:
- dbg_printf("%d ", buf[i]);
- break;
+ if (buf[i + 1] == SE) {
+ dbg_printf("IAC SE\n");
+ return i + 1;
+ }
+
+ /* skip over IAC IAC */
+ if (buf[i + 1] == IAC) {
+ dbg_printf("%d \n", IAC);
+ i++;
+ }
}
- i++;
- }
- dbg_printf("\n");
- return len;
+ /* the subneg string isn't finished yet */
+ if (i == len - 1)
+ dbg_printf("%d", buf[i]);
+ dbg_printf("\\\n");
+ fprintf(stderr, "Incomplete SB string\n");
+
+ return -EINVAL;
+ }
}
static int logfd = -1;
@@ -194,7 +219,89 @@ static void write_receive_buf(const unsigned char *buf, int len)
write(logfd, buf, len);
}
-static void handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
+/* This function is called with buf[0] being IAC. */
+static int handle_command(struct ios_ops *ios, unsigned char *buf, int len)
+{
+ int ret;
+ const struct telnet_option *option;
+
+ switch (buf[1]) {
+ case SB:
+ dbg_printf("SB ");
+ ret = do_subneg(ios, &buf[2], len - 2);
+ if (ret < 0)
+ return ret;
+ return ret + 2;
+
+ case IAC:
+ /* escaped IAC -> unescape */
+ write_receive_buf(&buf[1], 1);
+ return 2;
+
+ case WILL:
+ option = get_telnet_option(buf[2]);
+ if (option)
+ dbg_printf("WILL %s", option->name);
+ else
+ dbg_printf("WILL #%d", buf[2]);
+
+ if (option && option->subneg_handler) {
+ /* ok, we already requested that, so take this as
+ * confirmation to actually do COM_PORT stuff.
+ * Everything is fine. Don't reconfirm to prevent an
+ * request/confirm storm.
+ */
+ dbg_printf("\n");
+ } else {
+ /* unknown/unimplemented option -> DONT */
+ dbg_printf(" -> DONT\n");
+ dprintf(ios->fd, "%c%c%c", IAC, DONT, buf[2]);
+ }
+ return 3;
+
+ case WONT:
+ option = get_telnet_option(buf[2]);
+ if (option)
+ dbg_printf("WONT %s\n", option->name);
+ else
+ dbg_printf("WONT #%d\n", buf[2]);
+ return 3;
+
+ case DO:
+ option = get_telnet_option(buf[2]);
+ if (option)
+ dbg_printf("DO %s", option->name);
+ else
+ dbg_printf("DO #%d", buf[2]);
+
+ if (option && option->sent_will) {
+ /*
+ * This is a confirmation of an WILL sent by us before.
+ * There is nothing to do now.
+ */
+ dbg_printf("\n");
+ } else {
+ /* Oh, cannot handle that one, so send a WONT */
+ dbg_printf(" -> WONT\n");
+ dprintf(ios->fd, "%c%c%c", IAC, WONT, buf[2]);
+ }
+ return 3;
+
+ case DONT:
+ option = get_telnet_option(buf[2]);
+ if (option)
+ dbg_printf("DONT %s\n", option->name);
+ else
+ dbg_printf("DONT #%d\n", buf[2]);
+ return 3;
+
+ default:
+ dbg_printf("??? %d\n", buf[1]);
+ return 1;
+ }
+}
+
+static int handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
{
unsigned char *sendbuf = buf;
int i;
@@ -204,7 +311,10 @@ static void handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
case IAC:
/* BUG: this is telnet specific */
write_receive_buf(sendbuf, buf - sendbuf);
- i = handle_command(buf, len);
+ i = handle_command(ios, buf, len);
+ if (i < 0)
+ return i;
+
buf += i;
len -= i;
sendbuf = buf;
@@ -213,6 +323,8 @@ static void handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
write_receive_buf(sendbuf, buf - sendbuf);
if (answerback)
write(ios->fd, answerback, strlen(answerback));
+ else
+ write_receive_buf(buf, 1);
buf += 1;
len -= 1;
@@ -226,6 +338,7 @@ static void handle_receive_buf(struct ios_ops *ios, unsigned char *buf, int len)
}
write_receive_buf(sendbuf, buf - sendbuf);
+ return 0;
}
/* handle escape characters, writing to output */
@@ -304,7 +417,9 @@ int mux_loop(struct ios_ops *ios)
return 0;
}
- handle_receive_buf(ios, buf, len);
+ i = handle_receive_buf(ios, buf, len);
+ if (i < 0)
+ return i;
}
if (!listenonly && FD_ISSET(STDIN_FILENO, &ready)) {
generated by cgit v1.2.3 (git 2.39.1) at 2024-05-01 06:16:28 +0000