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
39 static int port;
40
41 static int bufsize = 64 * 1024;
42
43 static const char procname[] = "dccpprobe";
44
45 struct {
46 struct kfifo *fifo;
47 spinlock_t lock;
48 wait_queue_head_t wait;
49 struct timeval tstart;
50 } dccpw;
51
52 static void printl(const char *fmt, ...)
53 {
54 va_list args;
55 int len;
56 struct timeval now;
57 char tbuf[256];
58
59 va_start(args, fmt);
60 do_gettimeofday(&now);
61
62 now.tv_sec -= dccpw.tstart.tv_sec;
63 now.tv_usec -= dccpw.tstart.tv_usec;
64 if (now.tv_usec < 0) {
65 --now.tv_sec;
66 now.tv_usec += 1000000;
67 }
68
69 len = sprintf(tbuf, "%lu.%06lu ",
70 (unsigned long) now.tv_sec,
71 (unsigned long) now.tv_usec);
72 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
73 va_end(args);
74
75 kfifo_put(dccpw.fifo, tbuf, len);
76 wake_up(&dccpw.wait);
77 }
78
79 static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
80 struct msghdr *msg, size_t size)
81 {
82 const struct dccp_minisock *dmsk = dccp_msk(sk);
83 const struct inet_sock *inet = inet_sk(sk);
84 const struct ccid3_hc_tx_sock *hctx;
85
86 if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
87 hctx = ccid3_hc_tx_sk(sk);
88 else
89 hctx = NULL;
90
91 if (port == 0 || ntohs(inet->dport) == port ||
92 ntohs(inet->sport) == port) {
93 if (hctx)
94 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u "
95 "%llu %llu %d\n",
96 NIPQUAD(inet->saddr), ntohs(inet->sport),
97 NIPQUAD(inet->daddr), ntohs(inet->dport), size,
98 hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
99 hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc,
100 hctx->ccid3hctx_x_recv >> 6,
101 hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi);
102 else
103 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
104 NIPQUAD(inet->saddr), ntohs(inet->sport),
105 NIPQUAD(inet->daddr), ntohs(inet->dport), size);
106 }
107
108 jprobe_return();
109 return 0;
110 }
111
112 static struct jprobe dccp_send_probe = {
113 .kp = {
114 .symbol_name = "dccp_sendmsg",
115 },
116 .entry = jdccp_sendmsg,
117 };
118
119 static int dccpprobe_open(struct inode *inode, struct file *file)
120 {
121 kfifo_reset(dccpw.fifo);
122 do_gettimeofday(&dccpw.tstart);
123 return 0;
124 }
125
126 static ssize_t dccpprobe_read(struct file *file, char __user *buf,
127 size_t len, loff_t *ppos)
128 {
129 int error = 0, cnt = 0;
130 unsigned char *tbuf;
131
132 if (!buf)
133 return -EINVAL;
134
135 if (len == 0)
136 return 0;
137
138 tbuf = vmalloc(len);
139 if (!tbuf)
140 return -ENOMEM;
141
142 error = wait_event_interruptible(dccpw.wait,
143 __kfifo_len(dccpw.fifo) != 0);
144 if (error)
145 goto out_free;
146
147 cnt = kfifo_get(dccpw.fifo, tbuf, len);
148 error = copy_to_user(buf, tbuf, cnt);
149
150 out_free:
151 vfree(tbuf);
152
153 return error ? error : cnt;
154 }
155
156 static const struct file_operations dccpprobe_fops = {
157 .owner = THIS_MODULE,
158 .open = dccpprobe_open,
159 .read = dccpprobe_read,
160 };
161
162 static __init int dccpprobe_init(void)
163 {
164 int ret = -ENOMEM;
165
166 init_waitqueue_head(&dccpw.wait);
167 spin_lock_init(&dccpw.lock);
168 dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
169 if (IS_ERR(dccpw.fifo))
170 return PTR_ERR(dccpw.fifo);
171
172 if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
173 goto err0;
174
175 ret = register_jprobe(&dccp_send_probe);
176 if (ret)
177 goto err1;
178
179 pr_info("DCCP watch registered (port=%d)\n", port);
180 return 0;
181 err1:
182 proc_net_remove(&init_net, procname);
183 err0:
184 kfifo_free(dccpw.fifo);
185 return ret;
186 }
187 module_init(dccpprobe_init);
188
189 static __exit void dccpprobe_exit(void)
190 {
191 kfifo_free(dccpw.fifo);
192 proc_net_remove(&init_net, procname);
193 unregister_jprobe(&dccp_send_probe);
194
195 }
196 module_exit(dccpprobe_exit);
197
198 MODULE_PARM_DESC(port, "Port to match (0=all)");
199 module_param(port, int, 0);
200
201 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
202 module_param(bufsize, int, 0);
203
204 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
205 MODULE_DESCRIPTION("DCCP snooper");
206 MODULE_LICENSE("GPL");
207
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