The Tcpdump Group git mirrors - tcpdump/blob - print-vxlan-gpe.c

   1 /* Copyright (c) 2015, bugyo
   2  * 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 are met:
   6  * 1. Redistributions of source code must retain the above copyright notice,
   7  *    this list of conditions and the following disclaimer.
   8  * 2. Redistributions in binary form must reproduce the above copyright notice,
   9  *    this list of conditions and the following disclaimer in the documentation
  10  *    and/or other materials provided with the distribution.
  11  *
  12  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
  13  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  14  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  15  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
  16  * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  17  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  18  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  19  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  20  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
  21  * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  22  */
  23
  24 #ifdef HAVE_CONFIG_H
  25 #include "config.h"
  26 #endif
  27
  28 #include <netdissect-stdinc.h>
  29
  30 #include "netdissect.h"
  31 #include "extract.h"
  32
  33 static const char tstr[] = " [|VXLAN-GPE]";
  34 static const struct tok vxlan_gpe_flags [] = {
  35     { 0x08, "I" },
  36     { 0x04, "P" },
  37     { 0x01, "O" },
  38     { 0, NULL }
  39 };
  40
  41 #define VXLAN_GPE_HDR_LEN 8
  42
  43 /*
  44  * VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-01
  45  *                   Generic Protocol Extension for VXLAN
  46  *
  47  *     0                   1                   2                   3
  48  *     0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
  49  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  50  *    |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
  51  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  52  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  53  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54  */
  55
  56 void
  57 vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
  58 {
  59     uint8_t flags;
  60     uint8_t next_protocol;
  61     uint32_t vni;
  62
  63     if (len < VXLAN_GPE_HDR_LEN)
  64         goto trunc;
  65
  66     ND_TCHECK2(*bp, VXLAN_GPE_HDR_LEN);
  67
  68     flags = *bp;
  69     bp += 3;
  70
  71     next_protocol = *bp;
  72     bp += 1;
  73
  74     vni = EXTRACT_24BITS(bp);
  75     bp += 4;
  76
  77     ND_PRINT((ndo, "VXLAN-GPE, "));
  78     ND_PRINT((ndo, "flags [%s], ",
  79               bittok2str_nosep(vxlan_gpe_flags, "none", flags)));
  80     ND_PRINT((ndo, "vni %u", vni));
  81     ND_PRINT((ndo, ndo->ndo_vflag ? "\n    " : ": "));
  82
  83     switch (next_protocol) {
  84     case 0x1:
  85         ip_print(ndo, bp, len - 8);
  86         break;
  87     case 0x2:
  88         ip6_print(ndo, bp, len - 8);
  89         break;
  90     case 0x3:
  91         ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
  92         break;
  93     case 0x4:
  94         nsh_print(ndo, bp, len - 8);
  95         break;
  96     case 0x5:
  97         mpls_print(ndo, bp, len - 8);
  98         break;
  99     default:
 100         ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
 101         return;
 102     }
 103
 104         return;
 105
 106 trunc:
 107         ND_PRINT((ndo, "%s", tstr));
 108 }
 109