contrib/tcpdump/print-mpls.c

   1 /*
   2  * Copyright (C) 2001 WIDE Project.  All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  * 1. Redistributions of source code must retain the above copyright
   8  *    notice, this list of conditions and the following disclaimer.
   9  * 2. Redistributions in binary form must reproduce the above copyright
  10  *    notice, this list of conditions and the following disclaimer in the
  11  *    documentation and/or other materials provided with the distribution.
  12  * 3. Neither the name of the project nor the names of its contributors
  13  *    may be used to endorse or promote products derived from this software
  14  *    without specific prior written permission.
  15  *
  16  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
  17  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  18  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  19  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
  20  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  21  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  22  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  23  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  24  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  26  * SUCH DAMAGE.
  27  */
  28
  29 #ifndef lint
  30 static const char rcsid[] _U_ =
  31     "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.14 2005-07-05 09:38:19 hannes Exp $ (LBL)";
  32 #endif
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <tcpdump-stdinc.h>
  39
  40 #include <stdio.h>
  41 #include <stdlib.h>
  42 #include <string.h>
  43
  44 #include "addrtoname.h"
  45 #include "interface.h"
  46 #include "extract.h"                    /* must come after interface.h */
  47 #include "mpls.h"
  48
  49 static const char *mpls_labelname[] = {
  50 /*0*/   "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
  51         "implicit NULL", "rsvd",
  52 /*5*/   "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  53 /*10*/  "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  54 /*15*/  "rsvd",
  55 };
  56
  57 /*
  58  * RFC3032: MPLS label stack encoding
  59  */
  60 void
  61 mpls_print(const u_char *bp, u_int length)
  62 {
  63         const u_char *p;
  64         u_int32_t label_entry;
  65         u_int16_t label_stack_depth = 0;
  66
  67         p = bp;
  68         printf("MPLS");
  69         do {
  70                 TCHECK2(*p, sizeof(label_entry));
  71                 label_entry = EXTRACT_32BITS(p);
  72                 printf("%s(label %u",
  73                        label_stack_depth ? "\n\t" : " ",
  74                        MPLS_LABEL(label_entry));
  75                 label_stack_depth++;
  76                 if (vflag &&
  77                     MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  78                         printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
  79                 printf(", exp %u", MPLS_EXP(label_entry));
  80                 if (MPLS_STACK(label_entry))
  81                         printf(", [S]");
  82                 printf(", ttl %u)", MPLS_TTL(label_entry));
  83
  84                 p += sizeof(label_entry);
  85         } while (!MPLS_STACK(label_entry));
  86
  87         switch (MPLS_LABEL(label_entry)) {
  88         case 0: /* IPv4 explicit NULL label */
  89         case 3: /* IPv4 implicit NULL label */
  90                 if (vflag>0) {
  91                         printf("\n\t");
  92                         ip_print(gndo, p, length - (p - bp));
  93                 }
  94                 else printf(", IP, length: %u",length);
  95                 break;
  96 #ifdef INET6
  97         case 2: /* IPv6 explicit NULL label */
  98                 if (vflag>0) {
  99                         printf("\n\t");
 100                         ip6_print(p, length - (p - bp));
 101                 }
 102                 else printf(", IPv6, length: %u",length);
 103                 break;
 104 #endif
 105         default:
 106                 /*
 107                  * Generally there's no indication of protocol in MPLS label
 108                  * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
 109                  * a technique that looks at the first payload byte if the BOS (bottom of stack)
 110                  * bit is set and tries to determine the network layer protocol
 111                  * 0x45-0x4f is IPv4
 112                  * 0x60-0x6f is IPv6
 113                  * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
 114                  * this technique is sometimes known as NULL encapsulation
 115                  * and decoding is particularly useful for control-plane traffic [BGP]
 116                  * which cisco by default sends MPLS encapsulated
 117                  */
 118
 119                 if (MPLS_STACK(label_entry)) { /* only do this if the stack bit is set */
 120                     switch(*p) {
 121                     case 0x45:
 122                     case 0x46:
 123                     case 0x47:
 124                     case 0x48:
 125                     case 0x49:
 126                     case 0x4a:
 127                     case 0x4b:
 128                     case 0x4c:
 129                     case 0x4d:
 130                     case 0x4e:
 131                     case 0x4f:
 132                         if (vflag>0) {
 133                             printf("\n\t");
 134                             ip_print(gndo, p, length - (p - bp));
 135                             }
 136                         else printf(", IP, length: %u",length);
 137                         break;
 138 #ifdef INET6
 139                     case 0x60:
 140                     case 0x61:
 141                     case 0x62:
 142                     case 0x63:
 143                     case 0x64:
 144                     case 0x65:
 145                     case 0x66:
 146                     case 0x67:
 147                     case 0x68:
 148                     case 0x69:
 149                     case 0x6a:
 150                     case 0x6b:
 151                     case 0x6c:
 152                     case 0x6d:
 153                     case 0x6e:
 154                     case 0x6f:
 155                         if (vflag>0) {
 156                             printf("\n\t");
 157                             ip6_print(p, length - (p - bp));
 158                             }
 159                         else printf(", IPv6, length: %u",length);
 160                         break;
 161 #endif
 162                     case 0x81:
 163                     case 0x82:
 164                     case 0x83:
 165                         if (vflag>0) {
 166                             printf("\n\t");
 167                             isoclns_print(p, length - (p - bp), length - (p - bp));
 168                             }
 169                         else printf(", OSI, length: %u",length);
 170                         break;
 171                     default:
 172                         /* ok bail out - we did not figure out what it is*/
 173                         break;
 174                     }
 175                 }
 176                 return;
 177         }
 178
 179 trunc:
 180         printf("[|MPLS]");
 181 }
 182
 183
 184 /*
 185  * Local Variables:
 186  * c-style: whitesmith
 187  * c-basic-offset: 8
 188  * End:
 189  */