blob: db3a42b8b34962594b7c8fe3e38b45cb68b19f83 [file] [log] [blame]
Wei Yongjun787a51a2010-04-30 22:41:09 -04001/*
2 * sctp_probe - Observe the SCTP 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 SCTP from Stephen Hemminger's code
8 * Copyright (C) 2010, Wei Yongjun <yjwei@cn.fujitsu.com>
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/sctp.h>
29#include <linux/proc_fs.h>
David S. Millerf5460612010-05-03 16:20:44 -070030#include <linux/vmalloc.h>
Wei Yongjun787a51a2010-04-30 22:41:09 -040031#include <linux/module.h>
32#include <linux/kfifo.h>
33#include <linux/time.h>
34#include <net/net_namespace.h>
35
36#include <net/sctp/sctp.h>
37#include <net/sctp/sm.h>
38
39MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
40MODULE_DESCRIPTION("SCTP snooper");
41MODULE_LICENSE("GPL");
42
43static int port __read_mostly = 0;
44MODULE_PARM_DESC(port, "Port to match (0=all)");
45module_param(port, int, 0);
46
47static int bufsize __read_mostly = 64 * 1024;
48MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
49module_param(bufsize, int, 0);
50
51static int full __read_mostly = 1;
52MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
53module_param(full, int, 0);
54
55static const char procname[] = "sctpprobe";
56
57static struct {
58 struct kfifo fifo;
59 spinlock_t lock;
60 wait_queue_head_t wait;
61 struct timespec tstart;
62} sctpw;
63
64static void printl(const char *fmt, ...)
65{
66 va_list args;
67 int len;
68 char tbuf[256];
69
70 va_start(args, fmt);
71 len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
72 va_end(args);
73
74 kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
75 wake_up(&sctpw.wait);
76}
77
78static int sctpprobe_open(struct inode *inode, struct file *file)
79{
80 kfifo_reset(&sctpw.fifo);
81 getnstimeofday(&sctpw.tstart);
82
83 return 0;
84}
85
86static ssize_t sctpprobe_read(struct file *file, char __user *buf,
87 size_t len, loff_t *ppos)
88{
89 int error = 0, cnt = 0;
90 unsigned char *tbuf;
91
92 if (!buf)
93 return -EINVAL;
94
95 if (len == 0)
96 return 0;
97
98 tbuf = vmalloc(len);
99 if (!tbuf)
100 return -ENOMEM;
101
102 error = wait_event_interruptible(sctpw.wait,
103 kfifo_len(&sctpw.fifo) != 0);
104 if (error)
105 goto out_free;
106
107 cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
108 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
109
110out_free:
111 vfree(tbuf);
112
113 return error ? error : cnt;
114}
115
116static const struct file_operations sctpprobe_fops = {
117 .owner = THIS_MODULE,
118 .open = sctpprobe_open,
119 .read = sctpprobe_read,
120};
121
122sctp_disposition_t jsctp_sf_eat_sack(const struct sctp_endpoint *ep,
123 const struct sctp_association *asoc,
124 const sctp_subtype_t type,
125 void *arg,
126 sctp_cmd_seq_t *commands)
127{
128 struct sctp_transport *sp;
129 static __u32 lcwnd = 0;
130 struct timespec now;
131
132 sp = asoc->peer.primary_path;
133
134 if ((full || sp->cwnd != lcwnd) &&
135 (!port || asoc->peer.port == port ||
136 ep->base.bind_addr.port == port)) {
137 lcwnd = sp->cwnd;
138
139 getnstimeofday(&now);
140 now = timespec_sub(now, sctpw.tstart);
141
142 printl("%lu.%06lu ", (unsigned long) now.tv_sec,
143 (unsigned long) now.tv_nsec / NSEC_PER_USEC);
144
145 printl("%p %5d %5d %5d %8d %5d ", asoc,
146 ep->base.bind_addr.port, asoc->peer.port,
147 asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
148
149 list_for_each_entry(sp, &asoc->peer.transport_addr_list,
150 transports) {
151 if (sp == asoc->peer.primary_path)
152 printl("*");
153
154 if (sp->ipaddr.sa.sa_family == AF_INET)
155 printl("%pI4 ", &sp->ipaddr.v4.sin_addr);
156 else
157 printl("%pI6 ", &sp->ipaddr.v6.sin6_addr);
158
159 printl("%2u %8u %8u %8u %8u %8u ",
160 sp->state, sp->cwnd, sp->ssthresh,
161 sp->flight_size, sp->partial_bytes_acked,
162 sp->pathmtu);
163 }
164 printl("\n");
165 }
166
167 jprobe_return();
168 return 0;
169}
170
171static struct jprobe sctp_recv_probe = {
172 .kp = {
173 .symbol_name = "sctp_sf_eat_sack_6_2",
174 },
175 .entry = jsctp_sf_eat_sack,
176};
177
178static __init int sctpprobe_init(void)
179{
180 int ret = -ENOMEM;
181
182 init_waitqueue_head(&sctpw.wait);
183 spin_lock_init(&sctpw.lock);
184 if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
185 return ret;
186
187 if (!proc_net_fops_create(&init_net, procname, S_IRUSR,
188 &sctpprobe_fops))
189 goto free_kfifo;
190
191 ret = register_jprobe(&sctp_recv_probe);
192 if (ret)
193 goto remove_proc;
194
195 pr_info("SCTP probe registered (port=%d)\n", port);
196
197 return 0;
198
199remove_proc:
200 proc_net_remove(&init_net, procname);
201free_kfifo:
202 kfifo_free(&sctpw.fifo);
203 return ret;
204}
205
206static __exit void sctpprobe_exit(void)
207{
208 kfifo_free(&sctpw.fifo);
209 proc_net_remove(&init_net, procname);
210 unregister_jprobe(&sctp_recv_probe);
211}
212
213module_init(sctpprobe_init);
214module_exit(sctpprobe_exit);