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 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include <tcpdump-stdinc.h>
  34
  35 #include <stdio.h>
  36 #include <stdlib.h>
  37 #include <string.h>
  38
  39 #include "interface.h"
  40 #include "extract.h"                    /* must come after interface.h */
  41 #include "mpls.h"
  42
  43 static const char *mpls_labelname[] = {
  44 /*0*/   "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
  45         "implicit NULL", "rsvd",
  46 /*5*/   "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  47 /*10*/  "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  48 /*15*/  "rsvd",
  49 };
  50
  51 enum mpls_packet_type {
  52         PT_UNKNOWN,
  53         PT_IPV4,
  54         PT_IPV6,
  55         PT_OSI
  56 };
  57
  58 /*
  59  * RFC3032: MPLS label stack encoding
  60  */
  61 void
  62 mpls_print(const u_char *bp, u_int length)
  63 {
  64         const u_char *p;
  65         u_int32_t label_entry;
  66         u_int16_t label_stack_depth = 0;
  67         enum mpls_packet_type pt = PT_UNKNOWN;
  68
  69         p = bp;
  70         printf("MPLS");
  71         do {
  72                 TCHECK2(*p, sizeof(label_entry));
  73                 label_entry = EXTRACT_32BITS(p);
  74                 printf("%s(label %u",
  75                        (label_stack_depth && vflag) ? "\n\t" : " ",
  76                        MPLS_LABEL(label_entry));
  77                 label_stack_depth++;
  78                 if (vflag &&
  79                     MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  80                         printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
  81                 printf(", exp %u", MPLS_EXP(label_entry));
  82                 if (MPLS_STACK(label_entry))
  83                         printf(", [S]");
  84                 printf(", ttl %u)", MPLS_TTL(label_entry));
  85
  86                 p += sizeof(label_entry);
  87         } while (!MPLS_STACK(label_entry));
  88
  89         /*
  90          * Try to figure out the packet type.
  91          */
  92         switch (MPLS_LABEL(label_entry)) {
  93
  94         case 0: /* IPv4 explicit NULL label */
  95         case 3: /* IPv4 implicit NULL label */
  96                 pt = PT_IPV4;
  97                 break;
  98
  99         case 2: /* IPv6 explicit NULL label */
 100                 pt = PT_IPV6;
 101                 break;
 102
 103         default:
 104                 /*
 105                  * Generally there's no indication of protocol in MPLS label
 106                  * encoding.
 107                  *
 108                  * However, draft-hsmit-isis-aal5mux-00.txt describes a
 109                  * technique for encapsulating IS-IS and IP traffic on the
 110                  * same ATM virtual circuit; you look at the first payload
 111                  * byte to determine the network layer protocol, based on
 112                  * the fact that
 113                  *
 114                  *      1) the first byte of an IP header is 0x45-0x4f
 115                  *         for IPv4 and 0x60-0x6f for IPv6;
 116                  *
 117                  *      2) the first byte of an OSI CLNP packet is 0x81,
 118                  *         the first byte of an OSI ES-IS packet is 0x82,
 119                  *         and the first byte of an OSI IS-IS packet is
 120                  *         0x83;
 121                  *
 122                  * so the network layer protocol can be inferred from the
 123                  * first byte of the packet, if the protocol is one of the
 124                  * ones listed above.
 125                  *
 126                  * Cisco sends control-plane traffic MPLS-encapsulated in
 127                  * this fashion.
 128                  */
 129                 switch(*p) {
 130
 131                 case 0x45:
 132                 case 0x46:
 133                 case 0x47:
 134                 case 0x48:
 135                 case 0x49:
 136                 case 0x4a:
 137                 case 0x4b:
 138                 case 0x4c:
 139                 case 0x4d:
 140                 case 0x4e:
 141                 case 0x4f:
 142                         pt = PT_IPV4;
 143                         break;
 144
 145                 case 0x60:
 146                 case 0x61:
 147                 case 0x62:
 148                 case 0x63:
 149                 case 0x64:
 150                 case 0x65:
 151                 case 0x66:
 152                 case 0x67:
 153                 case 0x68:
 154                 case 0x69:
 155                 case 0x6a:
 156                 case 0x6b:
 157                 case 0x6c:
 158                 case 0x6d:
 159                 case 0x6e:
 160                 case 0x6f:
 161                         pt = PT_IPV6;
 162                         break;
 163
 164                 case 0x81:
 165                 case 0x82:
 166                 case 0x83:
 167                         pt = PT_OSI;
 168                         break;
 169
 170                 default:
 171                         /* ok bail out - we did not figure out what it is*/
 172                         break;
 173                 }
 174         }
 175
 176         /*
 177          * Print the payload.
 178          */
 179         if (pt == PT_UNKNOWN) {
 180                 if (!suppress_default_print)
 181                         default_print(p, length - (p - bp));
 182                 return;
 183         }
 184         if (vflag)
 185                 printf("\n\t");
 186         else
 187                 printf(" ");
 188         switch (pt) {
 189
 190         case PT_IPV4:
 191                 ip_print(gndo, p, length - (p - bp));
 192                 break;
 193
 194         case PT_IPV6:
 195 #ifdef INET6
 196                 ip6_print(gndo, p, length - (p - bp));
 197 #else
 198                 printf("IPv6, length: %u", length);
 199 #endif
 200                 break;
 201
 202         case PT_OSI:
 203                 isoclns_print(p, length - (p - bp), length - (p - bp));
 204                 break;
 205
 206         default:
 207                 break;
 208         }
 209         return;
 210
 211 trunc:
 212         printf("[|MPLS]");
 213 }
 214
 215
 216 /*
 217  * Local Variables:
 218  * c-style: whitesmith
 219  * c-basic-offset: 8
 220  * End:
 221  */