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#include <net/net_namespace.h>
34
35#include "dccp.h"
36#include "ccid.h"
37#include "ccids/ccid3.h"
38
39static int port;
40
41static int bufsize = 64 * 1024;
42
43static const char procname[] = "dccpprobe";
44
45static struct {
46 struct kfifo *fifo;
47 spinlock_t lock;
48 wait_queue_head_t wait;
49 struct timespec tstart;
50} dccpw;
51
52static void printl(const char *fmt, ...)
53{
54 va_list args;
55 int len;
56 struct timespec now;
57 char tbuf[256];
58
59 va_start(args, fmt);
60 getnstimeofday(&now);
61
62 now = timespec_sub(now, dccpw.tstart);
63
64 len = sprintf(tbuf, "%lu.%06lu ",
65 (unsigned long) now.tv_sec,
66 (unsigned long) now.tv_nsec / NSEC_PER_USEC);
67 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
68 va_end(args);
69
70 kfifo_put(dccpw.fifo, tbuf, len);
71 wake_up(&dccpw.wait);
72}
73
74static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
75 struct msghdr *msg, size_t size)
76{
77 const struct dccp_minisock *dmsk = dccp_msk(sk);
78 const struct inet_sock *inet = inet_sk(sk);
79 const struct ccid3_hc_tx_sock *hctx;
80
81 if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
82 hctx = ccid3_hc_tx_sk(sk);
83 else
84 hctx = NULL;
85
86 if (port == 0 || ntohs(inet->dport) == port ||
87 ntohs(inet->sport) == port) {
88 if (hctx)
89 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u "
90 "%llu %llu %d\n",
91 NIPQUAD(inet->saddr), ntohs(inet->sport),
92 NIPQUAD(inet->daddr), ntohs(inet->dport), size,
93 hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
94 hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc,
95 hctx->ccid3hctx_x_recv >> 6,
96 hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi);
97 else
98 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
99 NIPQUAD(inet->saddr), ntohs(inet->sport),
100 NIPQUAD(inet->daddr), ntohs(inet->dport), size);
101 }
102
103 jprobe_return();
104 return 0;
105}
106
107static struct jprobe dccp_send_probe = {
108 .kp = {
109 .symbol_name = "dccp_sendmsg",
110 },
111 .entry = jdccp_sendmsg,
112};
113
114static int dccpprobe_open(struct inode *inode, struct file *file)
115{
116 kfifo_reset(dccpw.fifo);
117 getnstimeofday(&dccpw.tstart);
118 return 0;
119}
120
121static ssize_t dccpprobe_read(struct file *file, char __user *buf,
122 size_t len, loff_t *ppos)
123{
124 int error = 0, cnt = 0;
125 unsigned char *tbuf;
126
127 if (!buf)
128 return -EINVAL;
129
130 if (len == 0)
131 return 0;
132
133 tbuf = vmalloc(len);
134 if (!tbuf)
135 return -ENOMEM;
136
137 error = wait_event_interruptible(dccpw.wait,
138 __kfifo_len(dccpw.fifo) != 0);
139 if (error)
140 goto out_free;
141
142 cnt = kfifo_get(dccpw.fifo, tbuf, len);
143 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
144
145out_free:
146 vfree(tbuf);
147
148 return error ? error : cnt;
149}
150
151static const struct file_operations dccpprobe_fops = {
152 .owner = THIS_MODULE,
153 .open = dccpprobe_open,
154 .read = dccpprobe_read,
155};
156
157static __init int dccpprobe_init(void)
158{
159 int ret = -ENOMEM;
160
161 init_waitqueue_head(&dccpw.wait);
162 spin_lock_init(&dccpw.lock);
163 dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
164 if (IS_ERR(dccpw.fifo))
165 return PTR_ERR(dccpw.fifo);
166
167 if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
168 goto err0;
169
170 ret = register_jprobe(&dccp_send_probe);
171 if (ret)
172 goto err1;
173
174 pr_info("DCCP watch registered (port=%d)\n", port);
175 return 0;
176err1:
177 proc_net_remove(&init_net, procname);
178err0:
179 kfifo_free(dccpw.fifo);
180 return ret;
181}
182module_init(dccpprobe_init);
183
184static __exit void dccpprobe_exit(void)
185{
186 kfifo_free(dccpw.fifo);
187 proc_net_remove(&init_net, procname);
188 unregister_jprobe(&dccp_send_probe);
189
190}
191module_exit(dccpprobe_exit);
192
193MODULE_PARM_DESC(port, "Port to match (0=all)");
194module_param(port, int, 0);
195
196MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
197module_param(bufsize, int, 0);
198
199MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
200MODULE_DESCRIPTION("DCCP snooper");
201MODULE_LICENSE("GPL");