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Ian McDonalde41542f2006-09-22 14:28:01 +12001/*
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)
Gerrit Renkerfddc2fe2007-03-20 15:02:10 -030093 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u "
94 "%llu %llu %d\n",
95 NIPQUAD(inet->saddr), ntohs(inet->sport),
96 NIPQUAD(inet->daddr), ntohs(inet->dport), size,
97 hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
98 hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc,
99 hctx->ccid3hctx_x_recv >> 6,
100 hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi);
Ian McDonalde41542f2006-09-22 14:28:01 +1200101 else
102 printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
Gerrit Renkerfddc2fe2007-03-20 15:02:10 -0300103 NIPQUAD(inet->saddr), ntohs(inet->sport),
104 NIPQUAD(inet->daddr), ntohs(inet->dport), size);
Ian McDonalde41542f2006-09-22 14:28:01 +1200105 }
106
107 jprobe_return();
108 return 0;
109}
110
111static struct jprobe dccp_send_probe = {
Ian McDonalde1b74412006-11-20 18:41:37 -0200112 .kp = {
113 .symbol_name = "dccp_sendmsg",
114 },
Michael Ellerman9e367d82007-07-19 01:48:10 -0700115 .entry = jdccp_sendmsg,
Ian McDonalde41542f2006-09-22 14:28:01 +1200116};
117
118static int dccpprobe_open(struct inode *inode, struct file *file)
119{
120 kfifo_reset(dccpw.fifo);
121 do_gettimeofday(&dccpw.tstart);
122 return 0;
123}
124
125static ssize_t dccpprobe_read(struct file *file, char __user *buf,
126 size_t len, loff_t *ppos)
127{
128 int error = 0, cnt = 0;
129 unsigned char *tbuf;
130
Bill Nottingham75202e72007-05-31 21:33:35 -0700131 if (!buf)
Ian McDonalde41542f2006-09-22 14:28:01 +1200132 return -EINVAL;
133
134 if (len == 0)
135 return 0;
136
137 tbuf = vmalloc(len);
138 if (!tbuf)
139 return -ENOMEM;
140
141 error = wait_event_interruptible(dccpw.wait,
142 __kfifo_len(dccpw.fifo) != 0);
143 if (error)
144 goto out_free;
145
146 cnt = kfifo_get(dccpw.fifo, tbuf, len);
147 error = copy_to_user(buf, tbuf, cnt);
148
149out_free:
150 vfree(tbuf);
151
152 return error ? error : cnt;
153}
154
Arjan van de Ven9a321442007-02-12 00:55:35 -0800155static const struct file_operations dccpprobe_fops = {
Ian McDonalde41542f2006-09-22 14:28:01 +1200156 .owner = THIS_MODULE,
157 .open = dccpprobe_open,
158 .read = dccpprobe_read,
159};
160
161static __init int dccpprobe_init(void)
162{
163 int ret = -ENOMEM;
164
165 init_waitqueue_head(&dccpw.wait);
166 spin_lock_init(&dccpw.lock);
167 dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
Akinobu Mitaac16ca62006-11-22 20:26:11 -0800168 if (IS_ERR(dccpw.fifo))
169 return PTR_ERR(dccpw.fifo);
Ian McDonalde41542f2006-09-22 14:28:01 +1200170
171 if (!proc_net_fops_create(procname, S_IRUSR, &dccpprobe_fops))
172 goto err0;
173
174 ret = register_jprobe(&dccp_send_probe);
175 if (ret)
176 goto err1;
177
178 pr_info("DCCP watch registered (port=%d)\n", port);
179 return 0;
180err1:
181 proc_net_remove(procname);
182err0:
183 kfifo_free(dccpw.fifo);
184 return ret;
185}
186module_init(dccpprobe_init);
187
188static __exit void dccpprobe_exit(void)
189{
190 kfifo_free(dccpw.fifo);
191 proc_net_remove(procname);
192 unregister_jprobe(&dccp_send_probe);
193
194}
195module_exit(dccpprobe_exit);
196
197MODULE_PARM_DESC(port, "Port to match (0=all)");
198module_param(port, int, 0);
199
200MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
201module_param(bufsize, int, 0);
202
203MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
204MODULE_DESCRIPTION("DCCP snooper");
205MODULE_LICENSE("GPL");