tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * dccp_probe - Observe the DCCP flow with kprobes.
3 *
4 * The idea for this came from Werner Almesberger's umlsim
5 * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
6 *
7 * Modified for DCCP from Stephen Hemminger's code
8 * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 */
24
25#include <linux/kernel.h>
26#include <linux/kprobes.h>
27#include <linux/socket.h>
28#include <linux/dccp.h>
29#include <linux/proc_fs.h>
30#include <linux/module.h>
31#include <linux/kfifo.h>
32#include <linux/vmalloc.h>
33
34#include "dccp.h"
35#include "ccid.h"
36#include "ccids/ccid3.h"
37
38static int port;
39
40static int bufsize = 64 * 1024;
41
42static const char procname[] = "dccpprobe";
43
44struct {
45 struct kfifo *fifo;
46 spinlock_t lock;
47 wait_queue_head_t wait;
48 struct timeval tstart;
49} dccpw;
50
51static void printl(const char *fmt, ...)
52{
53 va_list args;
54 int len;
55 struct timeval now;
56 char tbuf[256];
57
58 va_start(args, fmt);
59 do_gettimeofday(&now);
60
61 now.tv_sec -= dccpw.tstart.tv_sec;
62 now.tv_usec -= dccpw.tstart.tv_usec;
63 if (now.tv_usec < 0) {
64 --now.tv_sec;
65 now.tv_usec += 1000000;
66 }
67
68 len = sprintf(tbuf, "%lu.%06lu ",
69 (unsigned long) now.tv_sec,
70 (unsigned long) now.tv_usec);
71 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
72 va_end(args);
73
74 kfifo_put(dccpw.fifo, tbuf, len);
75 wake_up(&dccpw.wait);
76}
77
78static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
79 struct msghdr *msg, size_t size)
80{
81 const struct dccp_minisock *dmsk = dccp_msk(sk);
82 const struct inet_sock *inet = inet_sk(sk);
83 const struct ccid3_hc_tx_sock *hctx;
84
85 if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
86 hctx = ccid3_hc_tx_sk(sk);
87 else
88 hctx = NULL;
89
90 if (port == 0 || ntohs(inet->dport) == port ||
91 ntohs(inet->sport) == port) {
92 if (hctx)
93 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %d\n",
94 NIPQUAD(inet->saddr), ntohs(inet->sport),
95 NIPQUAD(inet->daddr), ntohs(inet->dport), size,
96 hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
97 hctx->ccid3hctx_p, hctx->ccid3hctx_t_ipi);
98 else
99 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
100 NIPQUAD(inet->saddr), ntohs(inet->sport),
101 NIPQUAD(inet->daddr), ntohs(inet->dport), size);
102 }
103
104 jprobe_return();
105 return 0;
106}
107
108static struct jprobe dccp_send_probe = {
109 .kp = {
110 .symbol_name = "dccp_sendmsg",
111 },
112 .entry = JPROBE_ENTRY(jdccp_sendmsg),
113};
114
115static int dccpprobe_open(struct inode *inode, struct file *file)
116{
117 kfifo_reset(dccpw.fifo);
118 do_gettimeofday(&dccpw.tstart);
119 return 0;
120}
121
122static ssize_t dccpprobe_read(struct file *file, char __user *buf,
123 size_t len, loff_t *ppos)
124{
125 int error = 0, cnt = 0;
126 unsigned char *tbuf;
127
128 if (!buf || len < 0)
129 return -EINVAL;
130
131 if (len == 0)
132 return 0;
133
134 tbuf = vmalloc(len);
135 if (!tbuf)
136 return -ENOMEM;
137
138 error = wait_event_interruptible(dccpw.wait,
139 __kfifo_len(dccpw.fifo) != 0);
140 if (error)
141 goto out_free;
142
143 cnt = kfifo_get(dccpw.fifo, tbuf, len);
144 error = copy_to_user(buf, tbuf, cnt);
145
146out_free:
147 vfree(tbuf);
148
149 return error ? error : cnt;
150}
151
152static struct file_operations dccpprobe_fops = {
153 .owner = THIS_MODULE,
154 .open = dccpprobe_open,
155 .read = dccpprobe_read,
156};
157
158static __init int dccpprobe_init(void)
159{
160 int ret = -ENOMEM;
161
162 init_waitqueue_head(&dccpw.wait);
163 spin_lock_init(&dccpw.lock);
164 dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
165 if (IS_ERR(dccpw.fifo))
166 return PTR_ERR(dccpw.fifo);
167
168 if (!proc_net_fops_create(procname, S_IRUSR, &dccpprobe_fops))
169 goto err0;
170
171 ret = register_jprobe(&dccp_send_probe);
172 if (ret)
173 goto err1;
174
175 pr_info("DCCP watch registered (port=%d)\n", port);
176 return 0;
177err1:
178 proc_net_remove(procname);
179err0:
180 kfifo_free(dccpw.fifo);
181 return ret;
182}
183module_init(dccpprobe_init);
184
185static __exit void dccpprobe_exit(void)
186{
187 kfifo_free(dccpw.fifo);
188 proc_net_remove(procname);
189 unregister_jprobe(&dccp_send_probe);
190
191}
192module_exit(dccpprobe_exit);
193
194MODULE_PARM_DESC(port, "Port to match (0=all)");
195module_param(port, int, 0);
196
197MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
198module_param(bufsize, int, 0);
199
200MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
201MODULE_DESCRIPTION("DCCP snooper");
202MODULE_LICENSE("GPL");