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[] =
  31     "@(#) $Header: /tcpdump/master/tcpdump/print-mpls.c,v 1.3 2002-05-07 18:35:39 fenner Exp $ (LBL)";
  32 #endif
  33
  34 #ifdef HAVE_CONFIG_H
  35 #include "config.h"
  36 #endif
  37
  38 #include <sys/param.h>
  39 #include <sys/time.h>
  40 #include <sys/socket.h>
  41
  42 #include <netinet/in.h>
  43
  44 #include <stdio.h>
  45 #include <stdlib.h>
  46 #include <string.h>
  47 #include <unistd.h>
  48
  49 #include "addrtoname.h"
  50 #include "interface.h"
  51 #include "extract.h"                    /* must come after interface.h */
  52
  53 #define LABEL_MASK      0xfffff000
  54 #define LABEL_SHIFT     12
  55 #define EXP_MASK        0x00000e00
  56 #define EXP_SHIFT       9
  57 #define STACK_MASK      0x00000100
  58 #define STACK_SHIFT     8
  59 #define TTL_MASK        0x000000ff
  60 #define TTL_SHIFT       0
  61
  62 #define MPLS_LABEL(x)   (((x) & LABEL_MASK) >> LABEL_SHIFT)
  63 #define MPLS_EXP(x)     (((x) & EXP_MASK) >> EXP_SHIFT)
  64 #define MPLS_STACK(x)   (((x) & STACK_MASK) >> STACK_SHIFT)
  65 #define MPLS_TTL(x)     (((x) & TTL_MASK) >> TTL_SHIFT)
  66
  67 static const char *mpls_labelname[] = {
  68 /*0*/   "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
  69         "implicit NULL", "rsvd",
  70 /*5*/   "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  71 /*10*/  "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
  72 /*15*/  "rsvd",
  73 };
  74
  75 /*
  76  * RFC3032: MPLS label stack encoding
  77  */
  78 void
  79 mpls_print(const u_char *bp, u_int length)
  80 {
  81         const u_char *p;
  82         u_int32_t v;
  83
  84         p = bp;
  85         printf("MPLS");
  86         do {
  87                 TCHECK2(*p, sizeof(v));
  88                 v = EXTRACT_32BITS(p);
  89                 printf(" (");   /*)*/
  90                 printf("label 0x%x", MPLS_LABEL(v));
  91                 if (vflag &&
  92                     MPLS_LABEL(v) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
  93                         printf("(%s)", mpls_labelname[MPLS_LABEL(v)]);
  94                 if (MPLS_EXP(v))
  95                         printf(" exp 0x%x", MPLS_EXP(v));
  96                 if (MPLS_STACK(v))
  97                         printf("[S]");
  98                 printf(" TTL %u", MPLS_TTL(v));
  99                 /*(*/
 100                 printf(")");
 101
 102                 p += sizeof(v);
 103         } while (!MPLS_STACK(v));
 104
 105         switch (MPLS_LABEL(v)) {
 106         case 0: /* IPv4 explicit NULL label */
 107                 ip_print(p, length - (p - bp));
 108                 break;
 109 #ifdef INET6
 110         case 2: /* IPv6 explicit NULL label */
 111                 ip6_print(p, length - (p - bp));
 112                 break;
 113 #endif
 114         default:
 115                 /*
 116                  * Since there's no indication of protocol in MPLS label
 117                  * encoding, we can print nothing further.
 118                  */
 119                 return;
 120         }
 121
 122 trunc:
 123         printf("[|MPLS]");
 124 }