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[mirror_ubuntu-bionic-kernel.git] / net / sctp / probe.c
1 /*
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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
26
27 #include <linux/kernel.h>
28 #include <linux/kprobes.h>
29 #include <linux/socket.h>
30 #include <linux/sctp.h>
31 #include <linux/proc_fs.h>
32 #include <linux/vmalloc.h>
33 #include <linux/module.h>
34 #include <linux/kfifo.h>
35 #include <linux/time.h>
36 #include <net/net_namespace.h>
37
38 #include <net/sctp/sctp.h>
39 #include <net/sctp/sm.h>
40
41 MODULE_SOFTDEP("pre: sctp");
42 MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
43 MODULE_DESCRIPTION("SCTP snooper");
44 MODULE_LICENSE("GPL");
45
46 static int port __read_mostly = 0;
47 MODULE_PARM_DESC(port, "Port to match (0=all)");
48 module_param(port, int, 0);
49
50 static unsigned int fwmark __read_mostly = 0;
51 MODULE_PARM_DESC(fwmark, "skb mark to match (0=no mark)");
52 module_param(fwmark, uint, 0);
53
54 static int bufsize __read_mostly = 64 * 1024;
55 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
56 module_param(bufsize, int, 0);
57
58 static int full __read_mostly = 1;
59 MODULE_PARM_DESC(full, "Full log (1=every ack packet received, 0=only cwnd changes)");
60 module_param(full, int, 0);
61
62 static const char procname[] = "sctpprobe";
63
64 static struct {
65 struct kfifo fifo;
66 spinlock_t lock;
67 wait_queue_head_t wait;
68 struct timespec64 tstart;
69 } sctpw;
70
71 static __printf(1, 2) void printl(const char *fmt, ...)
72 {
73 va_list args;
74 int len;
75 char tbuf[256];
76
77 va_start(args, fmt);
78 len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
79 va_end(args);
80
81 kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
82 wake_up(&sctpw.wait);
83 }
84
85 static int sctpprobe_open(struct inode *inode, struct file *file)
86 {
87 kfifo_reset(&sctpw.fifo);
88 ktime_get_ts64(&sctpw.tstart);
89
90 return 0;
91 }
92
93 static ssize_t sctpprobe_read(struct file *file, char __user *buf,
94 size_t len, loff_t *ppos)
95 {
96 int error = 0, cnt = 0;
97 unsigned char *tbuf;
98
99 if (!buf)
100 return -EINVAL;
101
102 if (len == 0)
103 return 0;
104
105 tbuf = vmalloc(len);
106 if (!tbuf)
107 return -ENOMEM;
108
109 error = wait_event_interruptible(sctpw.wait,
110 kfifo_len(&sctpw.fifo) != 0);
111 if (error)
112 goto out_free;
113
114 cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
115 error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
116
117 out_free:
118 vfree(tbuf);
119
120 return error ? error : cnt;
121 }
122
123 static const struct file_operations sctpprobe_fops = {
124 .owner = THIS_MODULE,
125 .open = sctpprobe_open,
126 .read = sctpprobe_read,
127 .llseek = noop_llseek,
128 };
129
130 static sctp_disposition_t jsctp_sf_eat_sack(struct net *net,
131 const struct sctp_endpoint *ep,
132 const struct sctp_association *asoc,
133 const sctp_subtype_t type,
134 void *arg,
135 sctp_cmd_seq_t *commands)
136 {
137 struct sctp_chunk *chunk = arg;
138 struct sk_buff *skb = chunk->skb;
139 struct sctp_transport *sp;
140 static __u32 lcwnd = 0;
141 struct timespec64 now;
142
143 sp = asoc->peer.primary_path;
144
145 if (((port == 0 && fwmark == 0) ||
146 asoc->peer.port == port ||
147 ep->base.bind_addr.port == port ||
148 (fwmark > 0 && skb->mark == fwmark)) &&
149 (full || sp->cwnd != lcwnd)) {
150 lcwnd = sp->cwnd;
151
152 ktime_get_ts64(&now);
153 now = timespec64_sub(now, sctpw.tstart);
154
155 printl("%lu.%06lu ", (unsigned long) now.tv_sec,
156 (unsigned long) now.tv_nsec / NSEC_PER_USEC);
157
158 printl("%p %5d %5d %5d %8d %5d ", asoc,
159 ep->base.bind_addr.port, asoc->peer.port,
160 asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
161
162 list_for_each_entry(sp, &asoc->peer.transport_addr_list,
163 transports) {
164 if (sp == asoc->peer.primary_path)
165 printl("*");
166
167 printl("%pISc %2u %8u %8u %8u %8u %8u ",
168 &sp->ipaddr, sp->state, sp->cwnd, sp->ssthresh,
169 sp->flight_size, sp->partial_bytes_acked,
170 sp->pathmtu);
171 }
172 printl("\n");
173 }
174
175 jprobe_return();
176 return 0;
177 }
178
179 static struct jprobe sctp_recv_probe = {
180 .kp = {
181 .symbol_name = "sctp_sf_eat_sack_6_2",
182 },
183 .entry = jsctp_sf_eat_sack,
184 };
185
186 static __init int sctp_setup_jprobe(void)
187 {
188 int ret = register_jprobe(&sctp_recv_probe);
189
190 if (ret) {
191 if (request_module("sctp"))
192 goto out;
193 ret = register_jprobe(&sctp_recv_probe);
194 }
195
196 out:
197 return ret;
198 }
199
200 static __init int sctpprobe_init(void)
201 {
202 int ret = -ENOMEM;
203
204 /* Warning: if the function signature of sctp_sf_eat_sack_6_2,
205 * has been changed, you also have to change the signature of
206 * jsctp_sf_eat_sack, otherwise you end up right here!
207 */
208 BUILD_BUG_ON(__same_type(sctp_sf_eat_sack_6_2,
209 jsctp_sf_eat_sack) == 0);
210
211 init_waitqueue_head(&sctpw.wait);
212 spin_lock_init(&sctpw.lock);
213 if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
214 return ret;
215
216 if (!proc_create(procname, S_IRUSR, init_net.proc_net,
217 &sctpprobe_fops))
218 goto free_kfifo;
219
220 ret = sctp_setup_jprobe();
221 if (ret)
222 goto remove_proc;
223
224 pr_info("probe registered (port=%d/fwmark=%u) bufsize=%u\n",
225 port, fwmark, bufsize);
226 return 0;
227
228 remove_proc:
229 remove_proc_entry(procname, init_net.proc_net);
230 free_kfifo:
231 kfifo_free(&sctpw.fifo);
232 return ret;
233 }
234
235 static __exit void sctpprobe_exit(void)
236 {
237 kfifo_free(&sctpw.fifo);
238 remove_proc_entry(procname, init_net.proc_net);
239 unregister_jprobe(&sctp_recv_probe);
240 }
241
242 module_init(sctpprobe_init);
243 module_exit(sctpprobe_exit);