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 #include <config.h>
  22
  23 #define ND_LONGJMP_FROM_TCHECK
  24 #include "netdissect-stdinc.h"
  25
  26 #include "netdissect.h"
  27 #include "addrtoname.h"
  28 #include "extract.h"
  29
  30 #define MSDP_TYPE_MAX   7
  31
  32 void
  33 msdp_print(netdissect_options *ndo, const u_char *sp, u_int length)
  34 {
  35         unsigned int type, len;
  36
  37         ndo->ndo_protocol = "msdp";
  38         ND_PRINT(": ");
  39         nd_print_protocol(ndo);
  40         /* See if we think we're at the beginning of a compound packet */
  41         type = GET_U_1(sp);
  42         len = GET_BE_U_2(sp + 1);
  43         if (len > 1500 || len < 3 || type == 0 || type > MSDP_TYPE_MAX)
  44                 goto trunc;     /* not really truncated, but still not decodable */
  45         while (length != 0) {
  46                 unsigned int entry_count;
  47
  48                 if (length < 3)
  49                         goto trunc;
  50                 type = GET_U_1(sp);
  51                 len = GET_BE_U_2(sp + 1);
  52                 if (len > 1400 || ndo->ndo_vflag)
  53                         ND_PRINT(" [len %u]", len);
  54                 if (len < 3)
  55                         goto trunc;
  56                 if (length < len)
  57                         goto trunc;
  58                 switch (type) {
  59                 case 1: /* IPv4 Source-Active */
  60                 case 3: /* IPv4 Source-Active Response */
  61                         if (type == 1)
  62                                 ND_PRINT(" SA");
  63                         else
  64                                 ND_PRINT(" SA-Response");
  65
  66                         /* Entry Count */
  67                         if (len < 4)
  68                                 goto trunc;
  69                         entry_count = GET_U_1(sp + 3);
  70                         ND_PRINT(" %u entries", entry_count);
  71
  72                         /* RP Address */
  73                         if (len < 8)
  74                                 goto trunc;
  75                         /* XXX -print this based on ndo_vflag? */
  76                         ND_TCHECK_LEN(sp + 4, 4);
  77
  78                         /* Entries */
  79                         ND_TCHECK_LEN(sp + 8, entry_count*12);
  80
  81                         if (len > (8 + entry_count*12)) {
  82                                 /* Encapsulated IP packet */
  83                                 ND_PRINT(" [w/data]");
  84                                 if (ndo->ndo_vflag > 1) {
  85                                         ND_PRINT(" ");
  86                                         ip_print(ndo, sp + (8 + entry_count*12),
  87                                             len - (8 + entry_count*12));
  88                                 }
  89                         }
  90                         break;
  91                 case 2:
  92                         /* draft-ietf-msdp-spec-13 */
  93                         ND_PRINT(" SA-Request");
  94
  95                         /* Reserved */
  96                         if (len < 4)
  97                                 goto trunc;
  98                         ND_TCHECK_1(sp + 3);
  99
 100                         /* Group Address */
 101                         if (len < 8)
 102                                 goto trunc;
 103                         if (len != 8)
 104                                 ND_PRINT("[len=%u] ", len);
 105                         ND_PRINT(" for %s", GET_IPADDR_STRING(sp + 4));
 106                         break;
 107                 case 4:
 108                         ND_PRINT(" Keepalive");
 109                         if (len != 3)
 110                                 ND_PRINT("[len=%u] ", len);
 111                         break;
 112                 case 5:
 113                         ND_PRINT(" Notification");
 114                         break;
 115                 default:
 116                         ND_PRINT(" [type=%u len=%u]", type, len);
 117                         break;
 118                 }
 119                 ND_TCHECK_LEN(sp, len);
 120                 sp += len;
 121                 length -= len;
 122         }
 123         return;
 124 trunc:
 125         nd_print_trunc(ndo);
 126 }