The Tcpdump Group git mirrors - tcpdump/blob - print-msdp.c

   1 /*
   2  * Copyright (c) 2001 William C. Fenner.
   3  *                All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that: (1) source code
   7  * distributions retain the above copyright notice and this paragraph
   8  * in its entirety, and (2) distributions including binary code include
   9  * the above copyright notice and this paragraph in its entirety in
  10  * the documentation or other materials provided with the distribution.
  11  * The name of William C. Fenner may not be used to endorse or
  12  * promote products derived from this software without specific prior
  13  * written permission.  THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  14  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  15  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  16  * FOR A PARTICULAR PURPOSE.
  17  */
  18
  19 /* \summary: Multicast Source Discovery Protocol (MSDP) printer */
  20
  21 #ifdef HAVE_CONFIG_H
  22 #include <config.h>
  23 #endif
  24
  25 #include "netdissect-stdinc.h"
  26
  27 #include "netdissect.h"
  28 #include "addrtoname.h"
  29 #include "extract.h"
  30
  31 #define MSDP_TYPE_MAX   7
  32
  33 void
  34 msdp_print(netdissect_options *ndo, const u_char *sp, u_int length)
  35 {
  36         unsigned int type, len;
  37
  38         ndo->ndo_protocol = "msdp";
  39         ND_PRINT(": ");
  40         nd_print_protocol(ndo);
  41         /* See if we think we're at the beginning of a compound packet */
  42         type = GET_U_1(sp);
  43         len = GET_BE_U_2(sp + 1);
  44         if (len > 1500 || len < 3 || type == 0 || type > MSDP_TYPE_MAX)
  45                 goto trunc;     /* not really truncated, but still not decodable */
  46         while (length != 0) {
  47                 type = GET_U_1(sp);
  48                 len = GET_BE_U_2(sp + 1);
  49                 if (len > 1400 || ndo->ndo_vflag)
  50                         ND_PRINT(" [len %u]", len);
  51                 if (len < 3)
  52                         goto trunc;
  53                 if (length < len)
  54                         goto trunc;
  55                 sp += 3;
  56                 length -= 3;
  57                 switch (type) {
  58                 case 1: /* IPv4 Source-Active */
  59                 case 3: /* IPv4 Source-Active Response */
  60                         if (type == 1)
  61                                 ND_PRINT(" SA");
  62                         else
  63                                 ND_PRINT(" SA-Response");
  64                         ND_PRINT(" %u entries", GET_U_1(sp));
  65                         if ((u_int)((GET_U_1(sp) * 12) + 8) < len) {
  66                                 ND_PRINT(" [w/data]");
  67                                 if (ndo->ndo_vflag > 1) {
  68                                         ND_PRINT(" ");
  69                                         ip_print(ndo, sp +
  70                                                  GET_U_1(sp) * 12 + 8 - 3,
  71                                                  len - (GET_U_1(sp) * 12 + 8));
  72                                 }
  73                         }
  74                         break;
  75                 case 2:
  76                         ND_PRINT(" SA-Request");
  77                         ND_PRINT(" for %s", GET_IPADDR_STRING(sp + 1));
  78                         break;
  79                 case 4:
  80                         ND_PRINT(" Keepalive");
  81                         if (len != 3)
  82                                 ND_PRINT("[len=%u] ", len);
  83                         break;
  84                 case 5:
  85                         ND_PRINT(" Notification");
  86                         break;
  87                 default:
  88                         ND_PRINT(" [type=%u len=%u]", type, len);
  89                         break;
  90                 }
  91                 sp += (len - 3);
  92                 length -= (len - 3);
  93         }
  94         return;
  95 trunc:
  96         nd_print_trunc(ndo);
  97 }