1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
/*
* 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/vmalloc.h>
#include <net/tcp.h>
MODULE_AUTHOR("Stephen Hemminger <shemminger@osdl.org>");
MODULE_DESCRIPTION("TCP cwnd snooper");
MODULE_LICENSE("GPL");
static int port = 0;
MODULE_PARM_DESC(port, "Port to match (0=all)");
module_param(port, int, 0);
static int bufsize = 64*1024;
MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
module_param(bufsize, int, 0);
static const char procname[] = "tcpprobe";
struct {
struct kfifo *fifo;
spinlock_t lock;
wait_queue_head_t wait;
struct timeval tstart;
} tcpw;
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 -= tcpw.tstart.tv_sec;
now.tv_usec -= tcpw.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(tcpw.fifo, tbuf, len);
wake_up(&tcpw.wait);
}
static int jtcp_sendmsg(struct kiocb *iocb, struct sock *sk,
struct msghdr *msg, size_t size)
{
const struct tcp_sock *tp = tcp_sk(sk);
const struct inet_sock *inet = inet_sk(sk);
if (port == 0 || ntohs(inet->dport) == port ||
ntohs(inet->sport) == port) {
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),
size, tp->snd_nxt, tp->snd_una,
tp->snd_cwnd, tcp_current_ssthresh(sk),
tp->snd_wnd);
}
jprobe_return();
return 0;
}
static struct jprobe tcp_send_probe = {
.kp = { .addr = (kprobe_opcode_t *) &tcp_sendmsg, },
.entry = (kprobe_opcode_t *) &jtcp_sendmsg,
};
static int tcpprobe_open(struct inode * inode, struct file * file)
{
kfifo_reset(tcpw.fifo);
do_gettimeofday(&tcpw.tstart);
return 0;
}
static ssize_t tcpprobe_read(struct file *file, char __user *buf,
size_t len, loff_t *ppos)
{
int error = 0, cnt;
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)
return error;
cnt = kfifo_get(tcpw.fifo, tbuf, len);
error = copy_to_user(buf, tbuf, cnt);
vfree(tbuf);
return error ? error : cnt;
}
static 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 (!proc_net_fops_create(procname, S_IRUSR, &tcpprobe_fops))
goto err0;
ret = register_jprobe(&tcp_send_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_send_probe);
}
module_exit(tcpprobe_exit);
|
