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