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 /* \summary: Generic Protocol Extension for VXLAN (VXLAN GPE) printer */
  25
  26 /* specification: draft-ietf-nvo3-vxlan-gpe-01 */
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include "config.h"
  30 #endif
  31
  32 #include <netdissect-stdinc.h>
  33
  34 #include "netdissect.h"
  35 #include "extract.h"
  36
  37 static const char tstr[] = " [|VXLAN-GPE]";
  38 static const struct tok vxlan_gpe_flags [] = {
  39     { 0x08, "I" },
  40     { 0x04, "P" },
  41     { 0x01, "O" },
  42     { 0, NULL }
  43 };
  44
  45 #define VXLAN_GPE_HDR_LEN 8
  46
  47 /*
  48  * VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-01
  49  *                   Generic Protocol Extension for VXLAN
  50  *
  51  *     0                   1                   2                   3
  52  *     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
  53  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  54  *    |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
  55  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  56  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  57  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  58  */
  59
  60 void
  61 vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
  62 {
  63     uint8_t flags;
  64     uint8_t next_protocol;
  65     uint32_t vni;
  66
  67     if (len < VXLAN_GPE_HDR_LEN)
  68         goto trunc;
  69
  70     ND_TCHECK2(*bp, VXLAN_GPE_HDR_LEN);
  71
  72     flags = *bp;
  73     bp += 3;
  74
  75     next_protocol = *bp;
  76     bp += 1;
  77
  78     vni = EXTRACT_24BITS(bp);
  79     bp += 4;
  80
  81     ND_PRINT((ndo, "VXLAN-GPE, "));
  82     ND_PRINT((ndo, "flags [%s], ",
  83               bittok2str_nosep(vxlan_gpe_flags, "none", flags)));
  84     ND_PRINT((ndo, "vni %u", vni));
  85     ND_PRINT((ndo, ndo->ndo_vflag ? "\n    " : ": "));
  86
  87     switch (next_protocol) {
  88     case 0x1:
  89         ip_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
  90         break;
  91     case 0x2:
  92         ip6_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
  93         break;
  94     case 0x3:
  95         ether_print(ndo, bp, len - VXLAN_GPE_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
  96         break;
  97     case 0x4:
  98         nsh_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
  99         break;
 100     case 0x5:
 101         mpls_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
 102         break;
 103     default:
 104         ND_PRINT((ndo, "ERROR: unknown-next-protocol"));
 105         return;
 106     }
 107
 108         return;
 109
 110 trunc:
 111         ND_PRINT((ndo, "%s", tstr));
 112 }
 113