summaryrefslogtreecommitdiff
path: root/net/sctp/probe.c
blob: 34097a167431125af127a8b98f93aa2716a99953 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
/*
 * sctp_probe - Observe the SCTP flow with kprobes.
 *
 * The idea for this came from Werner Almesberger's umlsim
 * Copyright (C) 2004, Stephen Hemminger <shemminger@osdl.org>
 *
 * Modified for SCTP from Stephen Hemminger's code
 * Copyright (C) 2010, Wei Yongjun <yjwei@cn.fujitsu.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/kprobes.h>
#include <linux/socket.h>
#include <linux/sctp.h>
#include <linux/proc_fs.h>
#include <linux/vmalloc.h>
#include <linux/module.h>
#include <linux/kfifo.h>
#include <linux/time.h>
#include <net/net_namespace.h>

#include <net/sctp/sctp.h>
#include <net/sctp/sm.h>

MODULE_SOFTDEP("pre: sctp");
MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
MODULE_DESCRIPTION("SCTP snooper");
MODULE_LICENSE("GPL");

static int port __read_mostly = 0;
MODULE_PARM_DESC(port, "Port to match (0=all)");
module_param(port, int, 0);

static unsigned int fwmark __read_mostly = 0;
MODULE_PARM_DESC(fwmark, "skb mark to match (0=no mark)");
module_param(fwmark, uint, 0);

static int bufsize __read_mostly = 64 * 1024;
MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
module_param(bufsize, int, 0);

static int full __read_mostly = 1;
MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");
module_param(full, int, 0);

static const char procname[] = "sctpprobe";

static struct {
	struct kfifo	  fifo;
	spinlock_t	  lock;
	wait_queue_head_t wait;
	struct timespec64 tstart;
} sctpw;

static __printf(1, 2) void printl(const char *fmt, ...)
{
	va_list args;
	int len;
	char tbuf[256];

	va_start(args, fmt);
	len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
	va_end(args);

	kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
	wake_up(&sctpw.wait);
}

static int sctpprobe_open(struct inode *inode, struct file *file)
{
	kfifo_reset(&sctpw.fifo);
	ktime_get_ts64(&sctpw.tstart);

	return 0;
}

static ssize_t sctpprobe_read(struct file *file, char __user *buf,
			      size_t len, loff_t *ppos)
{
	int error = 0, cnt = 0;
	unsigned char *tbuf;

	if (!buf)
		return -EINVAL;

	if (len == 0)
		return 0;

	tbuf = vmalloc(len);
	if (!tbuf)
		return -ENOMEM;

	error = wait_event_interruptible(sctpw.wait,
					 kfifo_len(&sctpw.fifo) != 0);
	if (error)
		goto out_free;

	cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
	error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;

out_free:
	vfree(tbuf);

	return error ? error : cnt;
}

static const struct file_operations sctpprobe_fops = {
	.owner	= THIS_MODULE,
	.open	= sctpprobe_open,
	.read	= sctpprobe_read,
	.llseek = noop_llseek,
};

static sctp_disposition_t jsctp_sf_eat_sack(struct net *net,
					    const struct sctp_endpoint *ep,
					    const struct sctp_association *asoc,
					    const union sctp_subtype type,
					    void *arg,
					    struct sctp_cmd_seq *commands)
{
	struct sctp_chunk *chunk = arg;
	struct sk_buff *skb = chunk->skb;
	struct sctp_transport *sp;
	static __u32 lcwnd = 0;
	struct timespec64 now;

	sp = asoc->peer.primary_path;

	if (((port == 0 && fwmark == 0) ||
	     asoc->peer.port == port ||
	     ep->base.bind_addr.port == port ||
	     (fwmark > 0 && skb->mark == fwmark)) &&
	    (full || sp->cwnd != lcwnd)) {
		lcwnd = sp->cwnd;

		ktime_get_ts64(&now);
		now = timespec64_sub(now, sctpw.tstart);

		printl("%lu.%06lu ", (unsigned long) now.tv_sec,
		       (unsigned long) now.tv_nsec / NSEC_PER_USEC);

		printl("%p %5d %5d %5d %8d %5d ", asoc,
		       ep->base.bind_addr.port, asoc->peer.port,
		       asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);

		list_for_each_entry(sp, &asoc->peer.transport_addr_list,
					transports) {
			if (sp == asoc->peer.primary_path)
				printl("*");

			printl("%pISc %2u %8u %8u %8u %8u %8u ",
			       &sp->ipaddr, sp->state, sp->cwnd, sp->ssthresh,
			       sp->flight_size, sp->partial_bytes_acked,
			       sp->pathmtu);
		}
		printl("\n");
	}

	jprobe_return();
	return 0;
}

static struct jprobe sctp_recv_probe = {
	.kp	= {
		.symbol_name = "sctp_sf_eat_sack_6_2",
	},
	.entry	= jsctp_sf_eat_sack,
};

static __init int sctp_setup_jprobe(void)
{
	int ret = register_jprobe(&sctp_recv_probe);

	if (ret) {
		if (request_module("sctp"))
			goto out;
		ret = register_jprobe(&sctp_recv_probe);
	}

out:
	return ret;
}

static __init int sctpprobe_init(void)
{
	int ret = -ENOMEM;

	/* Warning: if the function signature of sctp_sf_eat_sack_6_2,
	 * has been changed, you also have to change the signature of
	 * jsctp_sf_eat_sack, otherwise you end up right here!
	 */
	BUILD_BUG_ON(__same_type(sctp_sf_eat_sack_6_2,
				 jsctp_sf_eat_sack) == 0);

	init_waitqueue_head(&sctpw.wait);
	spin_lock_init(&sctpw.lock);
	if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
		return ret;

	if (!proc_create(procname, S_IRUSR, init_net.proc_net,
			 &sctpprobe_fops))
		goto free_kfifo;

	ret = sctp_setup_jprobe();
	if (ret)
		goto remove_proc;

	pr_info("probe registered (port=%d/fwmark=%u) bufsize=%u\n",
		port, fwmark, bufsize);
	return 0;

remove_proc:
	remove_proc_entry(procname, init_net.proc_net);
free_kfifo:
	kfifo_free(&sctpw.fifo);
	return ret;
}

static __exit void sctpprobe_exit(void)
{
	kfifo_free(&sctpw.fifo);
	remove_proc_entry(procname, init_net.proc_net);
	unregister_jprobe(&sctp_recv_probe);
}

module_init(sctpprobe_init);
module_exit(sctpprobe_exit);