net/dccp/probe.c

   1 /*
   2  * dccp_probe - Observe the DCCP 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 DCCP from Stephen Hemminger's code
   8  * Copyright (C) 2006, Ian McDonald <ian.mcdonald@jandi.co.nz>
   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/dccp.h>
  29 #include <linux/proc_fs.h>
  30 #include <linux/module.h>
  31 #include <linux/kfifo.h>
  32 #include <linux/vmalloc.h>
  33 #include <net/net_namespace.h>
  34
  35 #include "dccp.h"
  36 #include "ccid.h"
  37 #include "ccids/ccid3.h"
  38
  39 static int port;
  40
  41 static int bufsize = 64 * 1024;
  42
  43 static const char procname[] = "dccpprobe";
  44
  45 struct {
  46         struct kfifo      *fifo;
  47         spinlock_t        lock;
  48         wait_queue_head_t wait;
  49         struct timeval    tstart;
  50 } dccpw;
  51
  52 static void printl(const char *fmt, ...)
  53 {
  54         va_list args;
  55         int len;
  56         struct timeval now;
  57         char tbuf[256];
  58
  59         va_start(args, fmt);
  60         do_gettimeofday(&now);
  61
  62         now.tv_sec -= dccpw.tstart.tv_sec;
  63         now.tv_usec -= dccpw.tstart.tv_usec;
  64         if (now.tv_usec < 0) {
  65                 --now.tv_sec;
  66                 now.tv_usec += 1000000;
  67         }
  68
  69         len = sprintf(tbuf, "%lu.%06lu ",
  70                       (unsigned long) now.tv_sec,
  71                       (unsigned long) now.tv_usec);
  72         len += vscnprintf(tbuf+len, sizeof(tbuf)-len, fmt, args);
  73         va_end(args);
  74
  75         kfifo_put(dccpw.fifo, tbuf, len);
  76         wake_up(&dccpw.wait);
  77 }
  78
  79 static int jdccp_sendmsg(struct kiocb *iocb, struct sock *sk,
  80                          struct msghdr *msg, size_t size)
  81 {
  82         const struct dccp_minisock *dmsk = dccp_msk(sk);
  83         const struct inet_sock *inet = inet_sk(sk);
  84         const struct ccid3_hc_tx_sock *hctx;
  85
  86         if (dmsk->dccpms_tx_ccid == DCCPC_CCID3)
  87                 hctx = ccid3_hc_tx_sk(sk);
  88         else
  89                 hctx = NULL;
  90
  91         if (port == 0 || ntohs(inet->dport) == port ||
  92             ntohs(inet->sport) == port) {
  93                 if (hctx)
  94                         printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d %d %d %d %u "
  95                                "%llu %llu %d\n",
  96                                NIPQUAD(inet->saddr), ntohs(inet->sport),
  97                                NIPQUAD(inet->daddr), ntohs(inet->dport), size,
  98                                hctx->ccid3hctx_s, hctx->ccid3hctx_rtt,
  99                                hctx->ccid3hctx_p, hctx->ccid3hctx_x_calc,
 100                                hctx->ccid3hctx_x_recv >> 6,
 101                                hctx->ccid3hctx_x >> 6, hctx->ccid3hctx_t_ipi);
 102                 else
 103                         printl("%d.%d.%d.%d:%u %d.%d.%d.%d:%u %d\n",
 104                                NIPQUAD(inet->saddr), ntohs(inet->sport),
 105                                NIPQUAD(inet->daddr), ntohs(inet->dport), size);
 106         }
 107
 108         jprobe_return();
 109         return 0;
 110 }
 111
 112 static struct jprobe dccp_send_probe = {
 113         .kp     = {
 114                 .symbol_name = "dccp_sendmsg",
 115         },
 116         .entry  = jdccp_sendmsg,
 117 };
 118
 119 static int dccpprobe_open(struct inode *inode, struct file *file)
 120 {
 121         kfifo_reset(dccpw.fifo);
 122         do_gettimeofday(&dccpw.tstart);
 123         return 0;
 124 }
 125
 126 static ssize_t dccpprobe_read(struct file *file, char __user *buf,
 127                               size_t len, loff_t *ppos)
 128 {
 129         int error = 0, cnt = 0;
 130         unsigned char *tbuf;
 131
 132         if (!buf)
 133                 return -EINVAL;
 134
 135         if (len == 0)
 136                 return 0;
 137
 138         tbuf = vmalloc(len);
 139         if (!tbuf)
 140                 return -ENOMEM;
 141
 142         error = wait_event_interruptible(dccpw.wait,
 143                                          __kfifo_len(dccpw.fifo) != 0);
 144         if (error)
 145                 goto out_free;
 146
 147         cnt = kfifo_get(dccpw.fifo, tbuf, len);
 148         error = copy_to_user(buf, tbuf, cnt) ? -EFAULT : 0;
 149
 150 out_free:
 151         vfree(tbuf);
 152
 153         return error ? error : cnt;
 154 }
 155
 156 static const struct file_operations dccpprobe_fops = {
 157         .owner   = THIS_MODULE,
 158         .open    = dccpprobe_open,
 159         .read    = dccpprobe_read,
 160 };
 161
 162 static __init int dccpprobe_init(void)
 163 {
 164         int ret = -ENOMEM;
 165
 166         init_waitqueue_head(&dccpw.wait);
 167         spin_lock_init(&dccpw.lock);
 168         dccpw.fifo = kfifo_alloc(bufsize, GFP_KERNEL, &dccpw.lock);
 169         if (IS_ERR(dccpw.fifo))
 170                 return PTR_ERR(dccpw.fifo);
 171
 172         if (!proc_net_fops_create(&init_net, procname, S_IRUSR, &dccpprobe_fops))
 173                 goto err0;
 174
 175         ret = register_jprobe(&dccp_send_probe);
 176         if (ret)
 177                 goto err1;
 178
 179         pr_info("DCCP watch registered (port=%d)\n", port);
 180         return 0;
 181 err1:
 182         proc_net_remove(&init_net, procname);
 183 err0:
 184         kfifo_free(dccpw.fifo);
 185         return ret;
 186 }
 187 module_init(dccpprobe_init);
 188
 189 static __exit void dccpprobe_exit(void)
 190 {
 191         kfifo_free(dccpw.fifo);
 192         proc_net_remove(&init_net, procname);
 193         unregister_jprobe(&dccp_send_probe);
 194
 195 }
 196 module_exit(dccpprobe_exit);
 197
 198 MODULE_PARM_DESC(port, "Port to match (0=all)");
 199 module_param(port, int, 0);
 200
 201 MODULE_PARM_DESC(bufsize, "Log buffer size (default 64k)");
 202 module_param(bufsize, int, 0);
 203
 204 MODULE_AUTHOR("Ian McDonald <ian.mcdonald@jandi.co.nz>");
 205 MODULE_DESCRIPTION("DCCP snooper");
 206 MODULE_LICENSE("GPL");