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/*
* dccp_probe - Observe the DCCP flow with kprobes.
*
* The idea for this came from Werner Almesberger's umlsim
* Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
*
* Modified for DCCP from Stephen Hemminger's code
* Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz>
*
* 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/socket.h>
#include <linux/dccp.h>
#include <linux/proc_fs.h>
#include <linux/module.h>
#include <linux/kfifo.h>
#include <linux/vmalloc.h>
#include <linux/time64.h>
#include <linux/gfp.h>
#include <net/net_namespace.h>
#include "dccp.h"
#include "ccid.h"
#include "ccids/ccid3.h"
static int port;
static int bufsize = 64 * 1024;
static const char procname[] = "dccpprobe";
static struct {
struct kfifo fifo;
spinlock_t lock;
wait_queue_head_t wait;
struct timespec64 tstart;
} dccpw;
static void printl(const char *fmt, ...)
{
va_list args;
int len;
struct timespec64 now;
char tbuf[256];
va_start(args, fmt);
getnstimeofday64(&now);
now = timespec64_sub(now, dccpw.tstart);
len = sprintf(tbuf, "%lu.%06lu ",
(unsigned long) now.tv_sec,
(unsigned long) now.tv_nsec / NSEC_PER_USEC);
len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
va_end(args);
kfifo_in_locked(&dccpw.fifo, tbuf, len, &dccpw.lock);
wake_up(&dccpw.wait);
}
static int jdccp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
{
const struct inet_sock *inet = inet_sk(sk);
struct ccid3_hc_tx_sock *hc = NULL;
if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3)
hc = ccid3_hc_tx_sk(sk);
if (port == 0 || ntohs(inet->inet_dport) == port ||
ntohs(inet->inet_sport) == port) {
if (hc)
printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n",
&inet->inet_saddr, ntohs(inet->inet_sport),
&inet->inet_daddr, ntohs(inet->inet_dport), size,
hc->tx_s, hc->tx_rtt, hc->tx_p,
hc->tx_x_calc, hc->tx_x_recv >> 6,
hc->tx_x >> 6, hc->tx_t_ipi);
else
printl("%pI4:%u %pI4:%u %d\n",
&inet->inet_saddr, ntohs(inet->inet_sport),
&inet->inet_daddr, ntohs(inet->inet_dport),
size);
}
jprobe_return();
return 0;
}
static struct jprobe dccp_send_probe = {
.kp = {
.symbol_name = "dccp_sendmsg",
},
.entry = jdccp_sendmsg,
};
static int dccpprobe_open(struct inode *inode, struct file *file)
{
kfifo_reset(&dccpw.fifo);
getnstimeofday64(&dccpw.tstart);
return 0;
}
static ssize_t dccpprobe_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
int error = 0, cnt = 0;
unsigned char *tbuf;
if (!buf)
return -EINVAL;
if (len == 0)
return 0;
tbuf = vmalloc(len);
if (!tbuf)
return -ENOMEM;
error = wait_event_interruptible(dccpw.wait,
kfifo_len(&dccpw.fifo) != 0);
if (error)
goto out_free;
cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock);
error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
out_free:
vfree(tbuf);
return error ? error : cnt;
}
static const struct file_operations dccpprobe_fops = {
.owner = THIS_MODULE,
.open = dccpprobe_open,
.read = dccpprobe_read,
.llseek = noop_llseek,
};
static __init int dccpprobe_init(void)
{
int ret = -ENOMEM;
init_waitqueue_head(&dccpw.wait);
spin_lock_init(&dccpw.lock);
if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL))
return ret;
if (!proc_create(procname, S_IRUSR, init_net.proc_net, &dccpprobe_fops))
goto err0;
ret = register_jprobe(&dccp_send_probe);
if (ret) {
ret = request_module("dccp");
if (!ret)
ret = register_jprobe(&dccp_send_probe);
}
if (ret)
goto err1;
pr_info("DCCP watch registered (port=%d)\n", port);
return 0;
err1:
remove_proc_entry(procname, init_net.proc_net);
err0:
kfifo_free(&dccpw.fifo);
return ret;
}
module_init(dccpprobe_init);
static __exit void dccpprobe_exit(void)
{
kfifo_free(&dccpw.fifo);
remove_proc_entry(procname, init_net.proc_net);
unregister_jprobe(&dccp_send_probe);
}
module_exit(dccpprobe_exit);
MODULE_PARM_DESC(port, "Port to match (0=all)");
module_param(port, int, 0);
MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
module_param(bufsize, int, 0);
MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
MODULE_DESCRIPTION("DCCP snooper");
MODULE_LICENSE("GPL");
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