external/bsd/tcpdump/dist/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 #include <sys/cdefs.h>
  30 #ifndef lint
  31 __RCSID("$NetBSD: print-mpls.c,v 1.5 2015/03/31 21:59:35 christos Exp $");
  32 #endif
  33
  34 #define NETDISSECT_REWORKED
  35 #ifdef HAVE_CONFIG_H
  36 #include "config.h"
  37 #endif
  38
  39 #include <tcpdump-stdinc.h>
  40
  41 #include "interface.h"
  42 #include "extract.h"                    /* must come after interface.h */
  43 #include "mpls.h"
  44
  45 static const char *mpls_labelname[] = {
  46 /*0*/   "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
  47         "implicit NULL", "rsvd",
  48 /*5*/   "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  49 /*10*/  "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  50 /*15*/  "rsvd",
  51 };
  52
  53 enum mpls_packet_type {
  54         PT_UNKNOWN,
  55         PT_IPV4,
  56         PT_IPV6,
  57         PT_OSI
  58 };
  59
  60 /*
  61  * RFC3032: MPLS label stack encoding
  62  */
  63 void
  64 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
  65 {
  66         const u_char *p;
  67         uint32_t label_entry;
  68         uint16_t label_stack_depth = 0;
  69         enum mpls_packet_type pt = PT_UNKNOWN;
  70
  71         p = bp;
  72         ND_PRINT((ndo, "MPLS"));
  73         do {
  74                 ND_TCHECK2(*p, sizeof(label_entry));
  75                 label_entry = EXTRACT_32BITS(p);
  76                 ND_PRINT((ndo, "%s(label %u",
  77                        (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
  78                        MPLS_LABEL(label_entry)));
  79                 label_stack_depth++;
  80                 if (ndo->ndo_vflag &&
  81                     MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  82                         ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)]));
  83                 ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry)));
  84                 if (MPLS_STACK(label_entry))
  85                         ND_PRINT((ndo, ", [S]"));
  86                 ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry)));
  87
  88                 p += sizeof(label_entry);
  89         } while (!MPLS_STACK(label_entry));
  90
  91         /*
  92          * Try to figure out the packet type.
  93          */
  94         switch (MPLS_LABEL(label_entry)) {
  95
  96         case 0: /* IPv4 explicit NULL label */
  97         case 3: /* IPv4 implicit NULL label */
  98                 pt = PT_IPV4;
  99                 break;
 100
 101         case 2: /* IPv6 explicit NULL label */
 102                 pt = PT_IPV6;
 103                 break;
 104
 105         default:
 106                 /*
 107                  * Generally there's no indication of protocol in MPLS label
 108                  * encoding.
 109                  *
 110                  * However, draft-hsmit-isis-aal5mux-00.txt describes a
 111                  * technique for encapsulating IS-IS and IP traffic on the
 112                  * same ATM virtual circuit; you look at the first payload
 113                  * byte to determine the network layer protocol, based on
 114                  * the fact that
 115                  *
 116                  *      1) the first byte of an IP header is 0x45-0x4f
 117                  *         for IPv4 and 0x60-0x6f for IPv6;
 118                  *
 119                  *      2) the first byte of an OSI CLNP packet is 0x81,
 120                  *         the first byte of an OSI ES-IS packet is 0x82,
 121                  *         and the first byte of an OSI IS-IS packet is
 122                  *         0x83;
 123                  *
 124                  * so the network layer protocol can be inferred from the
 125                  * first byte of the packet, if the protocol is one of the
 126                  * ones listed above.
 127                  *
 128                  * Cisco sends control-plane traffic MPLS-encapsulated in
 129                  * this fashion.
 130                  */
 131                 switch(*p) {
 132
 133                 case 0x45:
 134                 case 0x46:
 135                 case 0x47:
 136                 case 0x48:
 137                 case 0x49:
 138                 case 0x4a:
 139                 case 0x4b:
 140                 case 0x4c:
 141                 case 0x4d:
 142                 case 0x4e:
 143                 case 0x4f:
 144                         pt = PT_IPV4;
 145                         break;
 146
 147                 case 0x60:
 148                 case 0x61:
 149                 case 0x62:
 150                 case 0x63:
 151                 case 0x64:
 152                 case 0x65:
 153                 case 0x66:
 154                 case 0x67:
 155                 case 0x68:
 156                 case 0x69:
 157                 case 0x6a:
 158                 case 0x6b:
 159                 case 0x6c:
 160                 case 0x6d:
 161                 case 0x6e:
 162                 case 0x6f:
 163                         pt = PT_IPV6;
 164                         break;
 165
 166                 case 0x81:
 167                 case 0x82:
 168                 case 0x83:
 169                         pt = PT_OSI;
 170                         break;
 171
 172                 default:
 173                         /* ok bail out - we did not figure out what it is*/
 174                         break;
 175                 }
 176         }
 177
 178         /*
 179          * Print the payload.
 180          */
 181         if (pt == PT_UNKNOWN) {
 182                 if (!ndo->ndo_suppress_default_print)
 183                         ND_DEFAULTPRINT(p, length - (p - bp));
 184                 return;
 185         }
 186         ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
 187         switch (pt) {
 188
 189         case PT_IPV4:
 190                 ip_print(ndo, p, length - (p - bp));
 191                 break;
 192
 193         case PT_IPV6:
 194                 ip6_print(ndo, p, length - (p - bp));
 195                 break;
 196
 197         case PT_OSI:
 198                 isoclns_print(ndo, p, length - (p - bp), length - (p - bp));
 199                 break;
 200
 201         default:
 202                 break;
 203         }
 204         return;
 205
 206 trunc:
 207         ND_PRINT((ndo, "[|MPLS]"));
 208 }
 209
 210
 211 /*
 212  * Local Variables:
 213  * c-style: whitesmith
 214  * c-basic-offset: 8
 215  * End:
 216  */