sctp: remove 'resent' bit from the chunk
[linux-2.6.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 #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>
30 #include <linux/module.h>
31 #include <linux/kfifo.h>
32 #include <linux/time.h>
33 #include <net/net_namespace.h>
34
35 #include <net/sctp/sctp.h>
36 #include <net/sctp/sm.h>
37
38 MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
39 MODULE_DESCRIPTION("SCTP snooper");
40 MODULE_LICENSE("GPL");
41
42 static int port __read_mostly = 0;
43 MODULE_PARM_DESC(port, "Port to match (0=all)");
44 module_param(port, int, 0);
45
46 static int bufsize __read_mostly = 64 * 1024;
47 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
48 module_param(bufsize, int, 0);
49
50 static int full __read_mostly = 1;
51 MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");
52 module_param(full, int, 0);
53
54 static const char procname[] = "sctpprobe";
55
56 static struct {
57         struct kfifo      fifo;
58         spinlock_t        lock;
59         wait_queue_head_t wait;
60         struct timespec   tstart;
61 } sctpw;
62
63 static void printl(const char *fmt, ...)
64 {
65         va_list args;
66         int len;
67         char tbuf[256];
68
69         va_start(args, fmt);
70         len = vscnprintf(tbuf, sizeof(tbuf), fmt, args);
71         va_end(args);
72
73         kfifo_in_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
74         wake_up(&sctpw.wait);
75 }
76
77 static int sctpprobe_open(struct inode *inode, struct file *file)
78 {
79         kfifo_reset(&sctpw.fifo);
80         getnstimeofday(&sctpw.tstart);
81
82         return 0;
83 }
84
85 static ssize_t sctpprobe_read(struct file *file, char __user *buf,
86                               size_t len, loff_t *ppos)
87 {
88         int error = 0, cnt = 0;
89         unsigned char *tbuf;
90
91         if (!buf)
92                 return -EINVAL;
93
94         if (len == 0)
95                 return 0;
96
97         tbuf = vmalloc(len);
98         if (!tbuf)
99                 return -ENOMEM;
100
101         error = wait_event_interruptible(sctpw.wait,
102                                          kfifo_len(&sctpw.fifo) != 0);
103         if (error)
104                 goto out_free;
105
106         cnt = kfifo_out_locked(&sctpw.fifo, tbuf, len, &sctpw.lock);
107         error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
108
109 out_free:
110         vfree(tbuf);
111
112         return error ? error : cnt;
113 }
114
115 static const struct file_operations sctpprobe_fops = {
116         .owner  = THIS_MODULE,
117         .open   = sctpprobe_open,
118         .read   = sctpprobe_read,
119 };
120
121 sctp_disposition_t jsctp_sf_eat_sack(const struct sctp_endpoint *ep,
122                                      const struct sctp_association *asoc,
123                                      const sctp_subtype_t type,
124                                      void *arg,
125                                      sctp_cmd_seq_t *commands)
126 {
127         struct sctp_transport *sp;
128         static __u32 lcwnd = 0;
129         struct timespec now;
130
131         sp = asoc->peer.primary_path;
132
133         if ((full || sp->cwnd != lcwnd) &&
134             (!port || asoc->peer.port == port ||
135              ep->base.bind_addr.port == port)) {
136                 lcwnd = sp->cwnd;
137
138                 getnstimeofday(&now);
139                 now = timespec_sub(now, sctpw.tstart);
140
141                 printl("%lu.%06lu ", (unsigned long) now.tv_sec,
142                        (unsigned long) now.tv_nsec / NSEC_PER_USEC);
143
144                 printl("%p %5d %5d %5d %8d %5d ", asoc,
145                        ep->base.bind_addr.port, asoc->peer.port,
146                        asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
147
148                 list_for_each_entry(sp, &asoc->peer.transport_addr_list,
149                                         transports) {
150                         if (sp == asoc->peer.primary_path)
151                                 printl("*");
152
153                         if (sp->ipaddr.sa.sa_family == AF_INET)
154                                 printl("%pI4 ", &sp->ipaddr.v4.sin_addr);
155                         else
156                                 printl("%pI6 ", &sp->ipaddr.v6.sin6_addr);
157
158                         printl("%2u %8u %8u %8u %8u %8u ",
159                                sp->state, sp->cwnd, sp->ssthresh,
160                                sp->flight_size, sp->partial_bytes_acked,
161                                sp->pathmtu);
162                 }
163                 printl("\n");
164         }
165
166         jprobe_return();
167         return 0;
168 }
169
170 static struct jprobe sctp_recv_probe = {
171         .kp     = {
172                 .symbol_name = "sctp_sf_eat_sack_6_2",
173         },
174         .entry  = jsctp_sf_eat_sack,
175 };
176
177 static __init int sctpprobe_init(void)
178 {
179         int ret = -ENOMEM;
180
181         init_waitqueue_head(&sctpw.wait);
182         spin_lock_init(&sctpw.lock);
183         if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
184                 return ret;
185
186         if (!proc_net_fops_create(&init_net, procname, S_IRUSR,
187                                   &sctpprobe_fops))
188                 goto free_kfifo;
189
190         ret = register_jprobe(&sctp_recv_probe);
191         if (ret)
192                 goto remove_proc;
193
194         pr_info("SCTP probe registered (port=%d)\n", port);
195
196         return 0;
197
198 remove_proc:
199         proc_net_remove(&init_net, procname);
200 free_kfifo:
201         kfifo_free(&sctpw.fifo);
202         return ret;
203 }
204
205 static __exit void sctpprobe_exit(void)
206 {
207         kfifo_free(&sctpw.fifo);
208         proc_net_remove(&init_net, procname);
209         unregister_jprobe(&sctp_recv_probe);
210 }
211
212 module_init(sctpprobe_init);
213 module_exit(sctpprobe_exit);