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 "addrtoname.h"
  40 #include "interface.h"
  41 #include "extract.h"                    /* must come after interface.h */
  42 #include "mpls.h"
  43
  44 static const char *mpls_labelname[] = {
  45 /*0*/   "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
  46         "implicit NULL", "rsvd",
  47 /*5*/   "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  48 /*10*/  "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  49 /*15*/  "rsvd",
  50 };
  51
  52 enum mpls_packet_type {
  53         PT_UNKNOWN,
  54         PT_IPV4,
  55         PT_IPV6,
  56         PT_OSI
  57 };
  58
  59 /*
  60  * RFC3032: MPLS label stack encoding
  61  */
  62 void
  63 mpls_print(const u_char *bp, u_int length)
  64 {
  65         const u_char *p;
  66         u_int32_t label_entry;
  67         u_int16_t label_stack_depth = 0;
  68         enum mpls_packet_type pt = PT_UNKNOWN;
  69
  70         p = bp;
  71         printf("MPLS");
  72         do {
  73                 TCHECK2(*p, sizeof(label_entry));
  74                 label_entry = EXTRACT_32BITS(p);
  75                 printf("%s(label %u",
  76                        (label_stack_depth && vflag) ? "\n\t" : " ",
  77                        MPLS_LABEL(label_entry));
  78                 label_stack_depth++;
  79                 if (vflag &&
  80                     MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  81                         printf(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
  82                 printf(", exp %u", MPLS_EXP(label_entry));
  83                 if (MPLS_STACK(label_entry))
  84                         printf(", [S]");
  85                 printf(", ttl %u)", MPLS_TTL(label_entry));
  86
  87                 p += sizeof(label_entry);
  88         } while (!MPLS_STACK(label_entry));
  89
  90         /*
  91          * Try to figure out the packet type.
  92          */
  93         switch (MPLS_LABEL(label_entry)) {
  94
  95         case 0: /* IPv4 explicit NULL label */
  96         case 3: /* IPv4 implicit NULL label */
  97                 pt = PT_IPV4;
  98                 break;
  99
 100         case 2: /* IPv6 explicit NULL label */
 101                 pt = PT_IPV6;
 102                 break;
 103
 104         default:
 105                 /*
 106                  * Generally there's no indication of protocol in MPLS label
 107                  * encoding.
 108                  *
 109                  * However, draft-hsmit-isis-aal5mux-00.txt describes a
 110                  * technique for encapsulating IS-IS and IP traffic on the
 111                  * same ATM virtual circuit; you look at the first payload
 112                  * byte to determine the network layer protocol, based on
 113                  * the fact that
 114                  *
 115                  *      1) the first byte of an IP header is 0x45-0x4f
 116                  *         for IPv4 and 0x60-0x6f for IPv6;
 117                  *
 118                  *      2) the first byte of an OSI CLNP packet is 0x81,
 119                  *         the first byte of an OSI ES-IS packet is 0x82,
 120                  *         and the first byte of an OSI IS-IS packet is
 121                  *         0x83;
 122                  *
 123                  * so the network layer protocol can be inferred from the
 124                  * first byte of the packet, if the protocol is one of the
 125                  * ones listed above.
 126                  *
 127                  * Cisco sends control-plane traffic MPLS-encapsulated in
 128                  * this fashion.
 129                  */
 130                 switch(*p) {
 131
 132                 case 0x45:
 133                 case 0x46:
 134                 case 0x47:
 135                 case 0x48:
 136                 case 0x49:
 137                 case 0x4a:
 138                 case 0x4b:
 139                 case 0x4c:
 140                 case 0x4d:
 141                 case 0x4e:
 142                 case 0x4f:
 143                         pt = PT_IPV4;
 144                         break;
 145
 146                 case 0x60:
 147                 case 0x61:
 148                 case 0x62:
 149                 case 0x63:
 150                 case 0x64:
 151                 case 0x65:
 152                 case 0x66:
 153                 case 0x67:
 154                 case 0x68:
 155                 case 0x69:
 156                 case 0x6a:
 157                 case 0x6b:
 158                 case 0x6c:
 159                 case 0x6d:
 160                 case 0x6e:
 161                 case 0x6f:
 162                         pt = PT_IPV6;
 163                         break;
 164
 165                 case 0x81:
 166                 case 0x82:
 167                 case 0x83:
 168                         pt = PT_OSI;
 169                         break;
 170
 171                 default:
 172                         /* ok bail out - we did not figure out what it is*/
 173                         break;
 174                 }
 175         }
 176
 177         /*
 178          * Print the payload.
 179          */
 180         if (pt == PT_UNKNOWN) {
 181                 if (!suppress_default_print)
 182                         default_print(p, length - (p - bp));
 183                 return;
 184         }
 185         if (vflag)
 186                 printf("\n\t");
 187         else
 188                 printf(" ");
 189         switch (pt) {
 190
 191         case PT_IPV4:
 192                 ip_print(gndo, p, length - (p - bp));
 193                 break;
 194
 195         case PT_IPV6:
 196 #ifdef INET6
 197                 ip6_print(gndo, p, length - (p - bp));
 198 #else
 199                 printf("IPv6, length: %u", length);
 200 #endif
 201                 break;
 202
 203         case PT_OSI:
 204                 isoclns_print(p, length - (p - bp), length - (p - bp));
 205                 break;
 206
 207         default:
 208                 break;
 209         }
 210         return;
 211
 212 trunc:
 213         printf("[|MPLS]");
 214 }
 215
 216
 217 /*
 218  * Local Variables:
 219  * c-style: whitesmith
 220  * c-basic-offset: 8
 221  * End:
 222  */