The Tcpdump Group git mirrors - tcpdump/blob - 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 1.13 2005-04-06 21:32:41 mcr 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 v;
  65
  66         p = bp;
  67         printf("MPLS");
  68         do {
  69                 TCHECK2(*p, sizeof(v));
  70                 v = EXTRACT_32BITS(p);
  71                 printf(" (");   /*)*/
  72                 printf("label %u", MPLS_LABEL(v));
  73                 if (vflag &&
  74                     MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  75                         printf(" (%s)", mpls_labelname[MPLS_LABEL(v)]);
  76                 printf(", exp %u", MPLS_EXP(v));
  77                 if (MPLS_STACK(v))
  78                         printf(", [S]");
  79                 printf(", ttl %u", MPLS_TTL(v));
  80                 /*(*/
  81                 printf(")");
  82
  83                 p += sizeof(v);
  84         } while (!MPLS_STACK(v));
  85
  86         switch (MPLS_LABEL(v)) {
  87         case 0: /* IPv4 explicit NULL label */
  88         case 3: /* IPv4 implicit NULL label */
  89                 ip_print(gndo, p, length - (p - bp));
  90                 break;
  91 #ifdef INET6
  92         case 2: /* IPv6 explicit NULL label */
  93                 ip6_print(p, length - (p - bp));
  94                 break;
  95 #endif
  96         default:
  97                 /*
  98                  * Generally there's no indication of protocol in MPLS label
  99                  * encoding, however draft-hsmit-isis-aal5mux-00.txt describes
 100                  * a technique that looks at the first payload byte if the BOS (bottom of stack)
 101                  * bit is set and tries to determine the network layer protocol
 102                  * 0x45-0x4f is IPv4
 103                  * 0x60-0x6f is IPv6
 104                  * 0x81-0x83 is OSI (CLNP,ES-IS,IS-IS)
 105                  * this technique is sometimes known as NULL encapsulation
 106                  * and decoding is particularly useful for control-plane traffic [BGP]
 107                  * which cisco by default sends MPLS encapsulated
 108                  */
 109
 110                 if (MPLS_STACK(v)) { /* only do this if the stack bit is set */
 111                     switch(*p) {
 112                     case 0x45:
 113                     case 0x46:
 114                     case 0x47:
 115                     case 0x48:
 116                     case 0x49:
 117                     case 0x4a:
 118                     case 0x4b:
 119                     case 0x4c:
 120                     case 0x4d:
 121                     case 0x4e:
 122                     case 0x4f:
 123                         if (vflag>0) {
 124                             printf("\n\t");
 125                             ip_print(gndo, p, length - (p - bp));
 126                             }
 127                         else printf(", IP, length: %u",length);
 128                         break;
 129 #ifdef INET6
 130                     case 0x60:
 131                     case 0x61:
 132                     case 0x62:
 133                     case 0x63:
 134                     case 0x64:
 135                     case 0x65:
 136                     case 0x66:
 137                     case 0x67:
 138                     case 0x68:
 139                     case 0x69:
 140                     case 0x6a:
 141                     case 0x6b:
 142                     case 0x6c:
 143                     case 0x6d:
 144                     case 0x6e:
 145                     case 0x6f:
 146                         if (vflag>0) {
 147                             printf("\n\t");
 148                             ip6_print(p, length - (p - bp));
 149                             }
 150                         else printf(", IPv6, length: %u",length);
 151                         break;
 152 #endif
 153                     case 0x81:
 154                     case 0x82:
 155                     case 0x83:
 156                         if (vflag>0) {
 157                             printf("\n\t");
 158                             isoclns_print(p, length - (p - bp), length - (p - bp));
 159                             }
 160                         else printf(", OSI, length: %u",length);
 161                         break;
 162                     default:
 163                         /* ok bail out - we did not figure out what it is*/
 164                         break;
 165                     }
 166                 }
 167                 return;
 168         }
 169
 170 trunc:
 171         printf("[|MPLS]");
 172 }
 173
 174
 175 /*
 176  * Local Variables:
 177  * c-style: whitesmith
 178  * c-basic-offset: 8
 179  * End:
 180  */