![Stephen Hemminger](/assets/img/avatar_default.png)
Change tcp_probe to use ktime (needed to add one export). Add option to only get events when cwnd changes - from Doug Leith Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org> Signed-off-by: David S. Miller <davem@davemloft.net>
197 lines
4.8 KiB
C
197 lines
4.8 KiB
C
/*
|
|
* tcpprobe - Observe the TCP flow with kprobes.
|
|
*
|
|
* The idea for this came from Werner Almesberger's umlsim
|
|
* Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
|
|
*
|
|
* 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/tcp.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kfifo.h>
|
|
#include <linux/ktime.h>
|
|
#include <linux/time.h>
|
|
#include <linux/vmalloc.h>
|
|
|
|
#include <net/tcp.h>
|
|
|
|
MODULE_AUTHOR("Stephen Hemminger <shemminger@linux-foundation.org>");
|
|
MODULE_DESCRIPTION("TCP cwnd snooper");
|
|
MODULE_LICENSE("GPL");
|
|
|
|
static int port __read_mostly = 0;
|
|
MODULE_PARM_DESC(port, "Port to match (0=all)");
|
|
module_param(port, int, 0);
|
|
|
|
static int bufsize __read_mostly = 64*1024;
|
|
MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
|
|
module_param(bufsize, int, 0);
|
|
|
|
static int full __read_mostly;
|
|
MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
|
|
module_param(full, int, 0);
|
|
|
|
static const char procname[] = "tcpprobe";
|
|
|
|
struct {
|
|
struct kfifo *fifo;
|
|
spinlock_t lock;
|
|
wait_queue_head_t wait;
|
|
ktime_t start;
|
|
u32 lastcwnd;
|
|
} tcpw;
|
|
|
|
/*
|
|
* Print to log with timestamps.
|
|
* FIXME: causes an extra copy
|
|
*/
|
|
static void printl(const char *fmt, ...)
|
|
{
|
|
va_list args;
|
|
int len;
|
|
struct timespec tv;
|
|
char tbuf[256];
|
|
|
|
va_start(args, fmt);
|
|
/* want monotonic time since start of tcp_probe */
|
|
tv = ktime_to_timespec(ktime_sub(ktime_get(), tcpw.start));
|
|
|
|
len = sprintf(tbuf, "%lu.%09lu ",
|
|
(unsigned long) tv.tv_sec, (unsigned long) tv.tv_nsec);
|
|
len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
|
|
va_end(args);
|
|
|
|
kfifo_put(tcpw.fifo, tbuf, len);
|
|
wake_up(&tcpw.wait);
|
|
}
|
|
|
|
/*
|
|
* Hook inserted to be called before each receive packet.
|
|
* Note: arguments must match tcp_rcv_established()!
|
|
*/
|
|
static int jtcp_rcv_established(struct sock *sk, struct sk_buff *skb,
|
|
struct tcphdr *th, unsigned len)
|
|
{
|
|
const struct tcp_sock *tp = tcp_sk(sk);
|
|
const struct inet_sock *inet = inet_sk(sk);
|
|
|
|
/* Only update if port matches */
|
|
if ((port == 0 || ntohs(inet->dport) == port || ntohs(inet->sport) == port)
|
|
&& (full || tp->snd_cwnd != tcpw.lastcwnd)) {
|
|
printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %#x %#x %u %u %u\n",
|
|
NIPQUAD(inet->saddr), ntohs(inet->sport),
|
|
NIPQUAD(inet->daddr), ntohs(inet->dport),
|
|
skb->len, tp->snd_nxt, tp->snd_una,
|
|
tp->snd_cwnd, tcp_current_ssthresh(sk),
|
|
tp->snd_wnd, tp->srtt >> 3);
|
|
tcpw.lastcwnd = tp->snd_cwnd;
|
|
}
|
|
|
|
jprobe_return();
|
|
return 0;
|
|
}
|
|
|
|
static struct jprobe tcp_probe = {
|
|
.kp = {
|
|
.symbol_name = "tcp_rcv_established",
|
|
},
|
|
.entry = JPROBE_ENTRY(jtcp_rcv_established),
|
|
};
|
|
|
|
|
|
static int tcpprobe_open(struct inode * inode, struct file * file)
|
|
{
|
|
kfifo_reset(tcpw.fifo);
|
|
tcpw.start = ktime_get();
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t tcpprobe_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(tcpw.wait,
|
|
__kfifo_len(tcpw.fifo) != 0);
|
|
if (error)
|
|
goto out_free;
|
|
|
|
cnt = kfifo_get(tcpw.fifo, tbuf, len);
|
|
error = copy_to_user(buf, tbuf, cnt);
|
|
|
|
out_free:
|
|
vfree(tbuf);
|
|
|
|
return error ? error : cnt;
|
|
}
|
|
|
|
static const struct file_operations tcpprobe_fops = {
|
|
.owner = THIS_MODULE,
|
|
.open = tcpprobe_open,
|
|
.read = tcpprobe_read,
|
|
};
|
|
|
|
static __init int tcpprobe_init(void)
|
|
{
|
|
int ret = -ENOMEM;
|
|
|
|
init_waitqueue_head(&tcpw.wait);
|
|
spin_lock_init(&tcpw.lock);
|
|
tcpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &tcpw.lock);
|
|
if (IS_ERR(tcpw.fifo))
|
|
return PTR_ERR(tcpw.fifo);
|
|
|
|
if (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))
|
|
goto err0;
|
|
|
|
ret = register_jprobe(&tcp_probe);
|
|
if (ret)
|
|
goto err1;
|
|
|
|
pr_info("TCP watch registered (port=%d)\n", port);
|
|
return 0;
|
|
err1:
|
|
proc_net_remove(procname);
|
|
err0:
|
|
kfifo_free(tcpw.fifo);
|
|
return ret;
|
|
}
|
|
module_init(tcpprobe_init);
|
|
|
|
static __exit void tcpprobe_exit(void)
|
|
{
|
|
kfifo_free(tcpw.fifo);
|
|
proc_net_remove(procname);
|
|
unregister_jprobe(&tcp_probe);
|
|
|
|
}
|
|
module_exit(tcpprobe_exit);
|