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     ndo->ndo_protocol = "vxlan_gpe";
  68     if (len < VXLAN_GPE_HDR_LEN)
  69         goto trunc;
  70
  71     ND_TCHECK_LEN(bp, VXLAN_GPE_HDR_LEN);
  72
  73     flags = EXTRACT_U_1(bp);
  74     bp += 3;
  75
  76     next_protocol = EXTRACT_U_1(bp);
  77     bp += 1;
  78
  79     vni = EXTRACT_BE_U_3(bp);
  80     bp += 4;
  81
  82     ND_PRINT("VXLAN-GPE, ");
  83     ND_PRINT("flags [%s], ",
  84               bittok2str_nosep(vxlan_gpe_flags, "none", flags));
  85     ND_PRINT("vni %u", vni);
  86     ND_PRINT(ndo->ndo_vflag ? "\n    " : ": ");
  87
  88     switch (next_protocol) {
  89     case 0x1:
  90         ip_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
  91         break;
  92     case 0x2:
  93         ip6_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
  94         break;
  95     case 0x3:
  96         ether_print(ndo, bp, len - VXLAN_GPE_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
  97         break;
  98     case 0x4:
  99         nsh_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
 100         break;
 101     case 0x5:
 102         mpls_print(ndo, bp, len - VXLAN_GPE_HDR_LEN);
 103         break;
 104     default:
 105         ND_PRINT("ERROR: unknown-next-protocol");
 106         return;
 107     }
 108
 109         return;
 110
 111 trunc:
 112         ND_PRINT("%s", tstr);
 113 }
 114