llseek: automatically add .llseek fop
[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/vmalloc.h>
31 #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
39 MODULE_AUTHOR("Wei Yongjun <yjwei@cn.fujitsu.com>");
40 MODULE_DESCRIPTION("SCTP snooper");
41 MODULE_LICENSE("GPL");
42
43 static int port __read_mostly = 0;
44 MODULE_PARM_DESC(port, "Port to match (0=all)");
45 module_param(port, int, 0);
46
47 static int bufsize __read_mostly = 64 * 1024;
48 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
49 module_param(bufsize, int, 0);
50
51 static int full __read_mostly = 1;
52 MODULE_PARM_DESC(full, "Full log (1=every ack packet received,  0=only cwnd changes)");
53 module_param(full, int, 0);
54
55 static const char procname[] = "sctpprobe";
56
57 static struct {
58         struct kfifo      fifo;
59         spinlock_t        lock;
60         wait_queue_head_t wait;
61         struct timespec   tstart;
62 } sctpw;
63
64 static 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
78 static 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
86 static 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
110 out_free:
111         vfree(tbuf);
112
113         return error ? error : cnt;
114 }
115
116 static const struct file_operations sctpprobe_fops = {
117         .owner  = THIS_MODULE,
118         .open   = sctpprobe_open,
119         .read   = sctpprobe_read,
120         .llseek = noop_llseek,
121 };
122
123 sctp_disposition_t jsctp_sf_eat_sack(const struct sctp_endpoint *ep,
124                                      const struct sctp_association *asoc,
125                                      const sctp_subtype_t type,
126                                      void *arg,
127                                      sctp_cmd_seq_t *commands)
128 {
129         struct sctp_transport *sp;
130         static __u32 lcwnd = 0;
131         struct timespec now;
132
133         sp = asoc->peer.primary_path;
134
135         if ((full || sp->cwnd != lcwnd) &&
136             (!port || asoc->peer.port == port ||
137              ep->base.bind_addr.port == port)) {
138                 lcwnd = sp->cwnd;
139
140                 getnstimeofday(&now);
141                 now = timespec_sub(now, sctpw.tstart);
142
143                 printl("%lu.%06lu ", (unsigned long) now.tv_sec,
144                        (unsigned long) now.tv_nsec / NSEC_PER_USEC);
145
146                 printl("%p %5d %5d %5d %8d %5d ", asoc,
147                        ep->base.bind_addr.port, asoc->peer.port,
148                        asoc->pathmtu, asoc->peer.rwnd, asoc->unack_data);
149
150                 list_for_each_entry(sp, &asoc->peer.transport_addr_list,
151                                         transports) {
152                         if (sp == asoc->peer.primary_path)
153                                 printl("*");
154
155                         if (sp->ipaddr.sa.sa_family == AF_INET)
156                                 printl("%pI4 ", &sp->ipaddr.v4.sin_addr);
157                         else
158                                 printl("%pI6 ", &sp->ipaddr.v6.sin6_addr);
159
160                         printl("%2u %8u %8u %8u %8u %8u ",
161                                sp->state, sp->cwnd, sp->ssthresh,
162                                sp->flight_size, sp->partial_bytes_acked,
163                                sp->pathmtu);
164                 }
165                 printl("\n");
166         }
167
168         jprobe_return();
169         return 0;
170 }
171
172 static struct jprobe sctp_recv_probe = {
173         .kp     = {
174                 .symbol_name = "sctp_sf_eat_sack_6_2",
175         },
176         .entry  = jsctp_sf_eat_sack,
177 };
178
179 static __init int sctpprobe_init(void)
180 {
181         int ret = -ENOMEM;
182
183         init_waitqueue_head(&sctpw.wait);
184         spin_lock_init(&sctpw.lock);
185         if (kfifo_alloc(&sctpw.fifo, bufsize, GFP_KERNEL))
186                 return ret;
187
188         if (!proc_net_fops_create(&init_net, procname, S_IRUSR,
189                                   &sctpprobe_fops))
190                 goto free_kfifo;
191
192         ret = register_jprobe(&sctp_recv_probe);
193         if (ret)
194                 goto remove_proc;
195
196         pr_info("SCTP probe registered (port=%d)\n", port);
197
198         return 0;
199
200 remove_proc:
201         proc_net_remove(&init_net, procname);
202 free_kfifo:
203         kfifo_free(&sctpw.fifo);
204         return ret;
205 }
206
207 static __exit void sctpprobe_exit(void)
208 {
209         kfifo_free(&sctpw.fifo);
210         proc_net_remove(&init_net, procname);
211         unregister_jprobe(&sctp_recv_probe);
212 }
213
214 module_init(sctpprobe_init);
215 module_exit(sctpprobe_exit);