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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>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090033#include <linux/gfp.h>
Eric W. Biederman457c4cb2007-09-12 12:01:34 +020034#include <net/net_namespace.h>
Ian McDonalde41542f2006-09-22 14:28:01 +120035
36#include "dccp.h"
37#include "ccid.h"
38#include "ccids/ccid3.h"
39
40static int port;
41
42static int bufsize = 64 * 1024;
43
44static const char procname[] = "dccpprobe";
45
Gerrit Renker1e2f0e52008-06-11 11:19:09 +010046static struct {
Stefani Seibold45465482009-12-21 14:37:26 -080047 struct kfifo fifo;
Ian McDonalde41542f2006-09-22 14:28:01 +120048 spinlock_t lock;
49 wait_queue_head_t wait;
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -070050 struct timespec tstart;
Ian McDonalde41542f2006-09-22 14:28:01 +120051} dccpw;
52
53static void printl(const char *fmt, ...)
54{
55 va_list args;
56 int len;
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -070057 struct timespec now;
Ian McDonalde41542f2006-09-22 14:28:01 +120058 char tbuf[256];
59
60 va_start(args, fmt);
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -070061 getnstimeofday(&now);
Ian McDonalde41542f2006-09-22 14:28:01 +120062
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -070063 now = timespec_sub(now, dccpw.tstart);
Ian McDonalde41542f2006-09-22 14:28:01 +120064
65 len = sprintf(tbuf, "%lu.%06lu ",
66 (unsigned long) now.tv_sec,
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -070067 (unsigned long) now.tv_nsec / NSEC_PER_USEC);
Ian McDonalde41542f2006-09-22 14:28:01 +120068 len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
69 va_end(args);
70
Stefani Seibold7acd72e2009-12-21 14:37:28 -080071 kfifo_in_locked(&dccpw.fifo, tbuf, len, &dccpw.lock);
Ian McDonalde41542f2006-09-22 14:28:01 +120072 wake_up(&dccpw.wait);
73}
74
75static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
76 struct msghdr *msg, size_t size)
77{
Ian McDonalde41542f2006-09-22 14:28:01 +120078 const struct inet_sock *inet = inet_sk(sk);
Gerrit Renker996ccf42009-10-05 00:53:13 +000079 struct ccid3_hc_tx_sock *hc = NULL;
Ian McDonalde41542f2006-09-22 14:28:01 +120080
Gerrit Renker71c262a2008-11-23 16:04:59 -080081 if (ccid_get_current_tx_ccid(dccp_sk(sk)) == DCCPC_CCID3)
Gerrit Renker996ccf42009-10-05 00:53:13 +000082 hc = ccid3_hc_tx_sk(sk);
Ian McDonalde41542f2006-09-22 14:28:01 +120083
Eric Dumazetc720c7e2009-10-15 06:30:45 +000084 if (port == 0 || ntohs(inet->inet_dport) == port ||
85 ntohs(inet->inet_sport) == port) {
Gerrit Renker996ccf42009-10-05 00:53:13 +000086 if (hc)
Gerrit Renker388d5e92009-10-05 00:53:11 +000087 printl("%pI4:%u %pI4:%u %d %d %d %d %u %llu %llu %d\n",
Eric Dumazetc720c7e2009-10-15 06:30:45 +000088 &inet->inet_saddr, ntohs(inet->inet_sport),
89 &inet->inet_daddr, ntohs(inet->inet_dport), size,
Gerrit Renker996ccf42009-10-05 00:53:13 +000090 hc->tx_s, hc->tx_rtt, hc->tx_p,
91 hc->tx_x_calc, hc->tx_x_recv >> 6,
92 hc->tx_x >> 6, hc->tx_t_ipi);
Ian McDonalde41542f2006-09-22 14:28:01 +120093 else
Harvey Harrison21454aa2008-10-31 00:54:56 -070094 printl("%pI4:%u %pI4:%u %d\n",
Eric Dumazetc720c7e2009-10-15 06:30:45 +000095 &inet->inet_saddr, ntohs(inet->inet_sport),
96 &inet->inet_daddr, ntohs(inet->inet_dport),
97 size);
Ian McDonalde41542f2006-09-22 14:28:01 +120098 }
99
100 jprobe_return();
101 return 0;
102}
103
104static struct jprobe dccp_send_probe = {
Ian McDonalde1b74412006-11-20 18:41:37 -0200105 .kp = {
106 .symbol_name = "dccp_sendmsg",
107 },
Michael Ellerman9e367d82007-07-19 01:48:10 -0700108 .entry = jdccp_sendmsg,
Ian McDonalde41542f2006-09-22 14:28:01 +1200109};
110
111static int dccpprobe_open(struct inode *inode, struct file *file)
112{
Stefani Seibold45465482009-12-21 14:37:26 -0800113 kfifo_reset(&dccpw.fifo);
YOSHIFUJI Hideakicdd04d92008-04-21 14:28:45 -0700114 getnstimeofday(&dccpw.tstart);
Ian McDonalde41542f2006-09-22 14:28:01 +1200115 return 0;
116}
117
118static ssize_t dccpprobe_read(struct file *file, char __user *buf,
119 size_t len, loff_t *ppos)
120{
121 int error = 0, cnt = 0;
122 unsigned char *tbuf;
123
Bill Nottingham75202e72007-05-31 21:33:35 -0700124 if (!buf)
Ian McDonalde41542f2006-09-22 14:28:01 +1200125 return -EINVAL;
126
127 if (len == 0)
128 return 0;
129
130 tbuf = vmalloc(len);
131 if (!tbuf)
132 return -ENOMEM;
133
134 error = wait_event_interruptible(dccpw.wait,
Stefani Seibolde64c0262009-12-21 14:37:28 -0800135 kfifo_len(&dccpw.fifo) != 0);
Ian McDonalde41542f2006-09-22 14:28:01 +1200136 if (error)
137 goto out_free;
138
Stefani Seibold7acd72e2009-12-21 14:37:28 -0800139 cnt = kfifo_out_locked(&dccpw.fifo, tbuf, len, &dccpw.lock);
Pavel Emelyanov653252c2008-04-25 01:49:48 -0700140 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
Ian McDonalde41542f2006-09-22 14:28:01 +1200141
142out_free:
143 vfree(tbuf);
144
145 return error ? error : cnt;
146}
147
Arjan van de Ven9a321442007-02-12 00:55:35 -0800148static const struct file_operations dccpprobe_fops = {
Ian McDonalde41542f2006-09-22 14:28:01 +1200149 .owner = THIS_MODULE,
150 .open = dccpprobe_open,
151 .read = dccpprobe_read,
152};
153
154static __init int dccpprobe_init(void)
155{
156 int ret = -ENOMEM;
157
158 init_waitqueue_head(&dccpw.wait);
159 spin_lock_init(&dccpw.lock);
Stefani Seiboldc1e13f22009-12-21 14:37:27 -0800160 if (kfifo_alloc(&dccpw.fifo, bufsize, GFP_KERNEL))
Stefani Seibold45465482009-12-21 14:37:26 -0800161 return ret;
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200162 if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
Ian McDonalde41542f2006-09-22 14:28:01 +1200163 goto err0;
164
Gerrit Renker1386be52010-02-02 20:16:56 +0000165 try_then_request_module((ret = register_jprobe(&dccp_send_probe)) == 0,
166 "dccp");
Ian McDonalde41542f2006-09-22 14:28:01 +1200167 if (ret)
168 goto err1;
169
170 pr_info("DCCP watch registered (port=%d)\n", port);
171 return 0;
172err1:
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200173 proc_net_remove(&init_net, procname);
Ian McDonalde41542f2006-09-22 14:28:01 +1200174err0:
Stefani Seibold45465482009-12-21 14:37:26 -0800175 kfifo_free(&dccpw.fifo);
Ian McDonalde41542f2006-09-22 14:28:01 +1200176 return ret;
177}
178module_init(dccpprobe_init);
179
180static __exit void dccpprobe_exit(void)
181{
Stefani Seibold45465482009-12-21 14:37:26 -0800182 kfifo_free(&dccpw.fifo);
Eric W. Biederman457c4cb2007-09-12 12:01:34 +0200183 proc_net_remove(&init_net, procname);
Ian McDonalde41542f2006-09-22 14:28:01 +1200184 unregister_jprobe(&dccp_send_probe);
185
186}
187module_exit(dccpprobe_exit);
188
189MODULE_PARM_DESC(port, "Port to match (0=all)");
190module_param(port, int, 0);
191
192MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
193module_param(bufsize, int, 0);
194
195MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
196MODULE_DESCRIPTION("DCCP snooper");
197MODULE_LICENSE("GPL");