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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 static struct {
46 struct kfifo fifo;
47 spinlock_t lock;
48 wait_queue_head_t wait;
49 struct timespec tstart;
50 } dccpw;
51
52 static 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
74 static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
75 struct msghdr *msg, size_t size)
76 {
77 const struct inet_sock *inet = inet_sk(sk);
78 struct ccid3_hc_tx_sock *hc = NULL;
79
80 if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3)
81 hc = ccid3_hc_tx_sk(sk);
82
83 if (port == 0 || ntohs(inet->inet_dport) == port ||
84 ntohs(inet->inet_sport) == port) {
85 if (hc)
86 printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n",
87 &inet->inet_saddr, ntohs(inet->inet_sport),
88 &inet->inet_daddr, ntohs(inet->inet_dport), size,
89 hc->tx_s, hc->tx_rtt, hc->tx_p,
90 hc->tx_x_calc, hc->tx_x_recv >> 6,
91 hc->tx_x >> 6, hc->tx_t_ipi);
92 else
93 printl("%pI4:%u %pI4:%u %d\n",
94 &inet->inet_saddr, ntohs(inet->inet_sport),
95 &inet->inet_daddr, ntohs(inet->inet_dport),
96 size);
97 }
98
99 jprobe_return();
100 return 0;
101 }
102
103 static struct jprobe dccp_send_probe = {
104 .kp = {
105 .symbol_name = "dccp_sendmsg",
106 },
107 .entry = jdccp_sendmsg,
108 };
109
110 static int dccpprobe_open(struct inode *inode, struct file *file)
111 {
112 kfifo_reset(&dccpw.fifo);
113 getnstimeofday(&dccpw.tstart);
114 return 0;
115 }
116
117 static ssize_t dccpprobe_read(struct file *file, char __user *buf,
118 size_t len, loff_t *ppos)
119 {
120 int error = 0, cnt = 0;
121 unsigned char *tbuf;
122
123 if (!buf)
124 return -EINVAL;
125
126 if (len == 0)
127 return 0;
128
129 tbuf = vmalloc(len);
130 if (!tbuf)
131 return -ENOMEM;
132
133 error = wait_event_interruptible(dccpw.wait,
134 __kfifo_len(&dccpw.fifo) != 0);
135 if (error)
136 goto out_free;
137
138 cnt = kfifo_get(&dccpw.fifo, tbuf, len);
139 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
140
141 out_free:
142 vfree(tbuf);
143
144 return error ? error : cnt;
145 }
146
147 static const struct file_operations dccpprobe_fops = {
148 .owner = THIS_MODULE,
149 .open = dccpprobe_open,
150 .read = dccpprobe_read,
151 };
152
153 static __init int dccpprobe_init(void)
154 {
155 int ret = -ENOMEM;
156
157 init_waitqueue_head(&dccpw.wait);
158 spin_lock_init(&dccpw.lock);
159 if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL, &dccpw.lock))
160 return ret;
161 if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
162 goto err0;
163
164 ret = register_jprobe(&dccp_send_probe);
165 if (ret)
166 goto err1;
167
168 pr_info("DCCP watch registered (port=%d)\n", port);
169 return 0;
170 err1:
171 proc_net_remove(&init_net, procname);
172 err0:
173 kfifo_free(&dccpw.fifo);
174 return ret;
175 }
176 module_init(dccpprobe_init);
177
178 static __exit void dccpprobe_exit(void)
179 {
180 kfifo_free(&dccpw.fifo);
181 proc_net_remove(&init_net, procname);
182 unregister_jprobe(&dccp_send_probe);
183
184 }
185 module_exit(dccpprobe_exit);
186
187 MODULE_PARM_DESC(port, "Port to match (0=all)");
188 module_param(port, int, 0);
189
190 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
191 module_param(bufsize, int, 0);
192
193 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
194 MODULE_DESCRIPTION("DCCP snooper");
195 MODULE_LICENSE("GPL");