probe.c 4.7 KB

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