/*
* 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 "dccp.h"
#include "ccid.h"
#include "ccids/ccid3.h"
static int port;
static int bufsize = 64 * 1024;
static const char procname[] = "dccpprobe";
struct {
struct kfifo *fifo;
spinlock_t lock;
wait_queue_head_t wait;
struct timeval tstart;
} dccpw;
static void printl(const char *fmt, ...)
{
va_list args;
int len;
struct timeval now;
char tbuf[256];
va_start(args, fmt);
do_gettimeofday(&now);
now.tv_sec -= dccpw.tstart.tv_sec;
now.tv_usec -= dccpw.tstart.tv_usec;
if (now.tv_usec < 0) {
--now.tv_sec;
now.tv_usec += 1000000;
}
len = sprintf(tbuf, "%lu.%06lu ",
(unsigned long) now.tv_sec,
(unsigned long) now.tv_usec);
len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
va_end(args);
kfifo_put(dccpw.fifo, tbuf, len);
wake_up(&dccpw.wait);
}
static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t size)
{
const struct dccp_minisock *dmsk = dccp_msk(sk);
const struct inet_sock *inet = inet_sk(sk);
const struct ccid3_hc_tx_sock *hctx;
if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
hctx = ccid3_hc_tx_sk(sk);
else
hctx = NULL;
if (port == 0 || ntohs(inet->dport) == port ||
ntohs(inet->sport) == port) {
if (hctx)
printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %d\n",
NIPQUAD(inet->saddr), ntohs(inet->sport),
NIPQUAD(inet->daddr), ntohs(inet->dport), size,
hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
hctx->ccid3hctx_p, hctx->ccid3hctx_t_ipi);
else
printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
NIPQUAD(inet->saddr), ntohs(inet->sport),
NIPQUAD(inet->daddr), ntohs(inet->dport), size);
}
jprobe_return();
return 0;
}
static struct jprobe dccp_send_probe = {
.kp = {
.symbol_name = "dccp_sendmsg",
},
.entry = JPROBE_ENTRY(jdccp_sendmsg),
};
static int dccpprobe_open(struct inode *inode, struct file *file)
{
kfifo_reset(dccpw.fifo);
do_gettimeofday(&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 || len < 0)
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_get(dccpw.fifo, tbuf, len);
error = copy_to_user(buf, tbuf, cnt);
out_free:
vfree(tbuf);
return error ? error : cnt;
}
static const struct file_operations dccpprobe_fops = {
.owner = THIS_MODULE,
.open = dccpprobe_open,
.read = dccpprobe_read,
};
static __init int dccpprobe_init(void)
{
int ret = -ENOMEM;
init_waitqueue_head(&dccpw.wait);
spin_lock_init(&dccpw.lock);
dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
if (IS_ERR(dccpw.fifo))
return PTR_ERR(dccpw.fifo);
if (!proc_net_fops_create(procname, S_IRUSR, &dccpprobe_fops))
goto err0;
ret = register_jprobe(&dccp_send_probe);
if (ret)
goto err1;
pr_info("DCCP watch registered (port=%d)\n", port);
return 0;
err1:
proc_net_remove(procname);
err0:
kfifo_free(dccpw.fifo);
return ret;
}
module_init(dccpprobe_init);
static __exit void dccpprobe_exit(void)
{
kfifo_free(dccpw.fifo);
proc_net_remove(procname);
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");
