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-10 */
  27
  28 #ifdef HAVE_CONFIG_H
  29 #include <config.h>
  30 #endif
  31
  32 #include "netdissect-stdinc.h"
  33
  34 #define ND_LONGJMP_FROM_TCHECK
  35 #include "netdissect.h"
  36 #include "extract.h"
  37
  38 static const struct tok vxlan_gpe_flags [] = {
  39     { 0x08, "I" },
  40     { 0x04, "P" },
  41     { 0x02, "B" },
  42     { 0x01, "O" },
  43     { 0, NULL }
  44 };
  45
  46 #define VXLAN_GPE_HDR_LEN 8
  47
  48 /*
  49  * VXLAN GPE header, draft-ietf-nvo3-vxlan-gpe-01
  50  *                   Generic Protocol Extension for VXLAN
  51  *
  52  *     0                   1                   2                   3
  53  *     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
  54  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  55  *    |R|R|Ver|I|P|R|O|       Reserved                |Next Protocol  |
  56  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  57  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  58  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  59  */
  60
  61 void
  62 vxlan_gpe_print(netdissect_options *ndo, const u_char *bp, u_int len)
  63 {
  64     uint8_t flags;
  65     uint8_t next_protocol;
  66     uint32_t vni;
  67
  68     ndo->ndo_protocol = "vxlan_gpe";
  69     ND_PRINT("VXLAN-GPE, ");
  70     if (len < VXLAN_GPE_HDR_LEN) {
  71         ND_PRINT(" (len %u < %u)", len, VXLAN_GPE_HDR_LEN);
  72         goto invalid;
  73     }
  74
  75     flags = GET_U_1(bp);
  76     bp += 1;
  77     len -= 1;
  78     ND_PRINT("flags [%s], ",
  79               bittok2str_nosep(vxlan_gpe_flags, "none", flags));
  80
  81     /* Reserved */
  82     bp += 2;
  83     len -= 2;
  84
  85     next_protocol = GET_U_1(bp);
  86     bp += 1;
  87     len -= 1;
  88
  89     vni = GET_BE_U_3(bp);
  90     bp += 3;
  91     len -= 3;
  92
  93     /* Reserved */
  94     ND_TCHECK_1(bp);
  95     bp += 1;
  96     len -= 1;
  97
  98     ND_PRINT("vni %u", vni);
  99     ND_PRINT(ndo->ndo_vflag ? "\n    " : ": ");
 100
 101     switch (next_protocol) {
 102     case 0x1:
 103         ip_print(ndo, bp, len);
 104         break;
 105     case 0x2:
 106         ip6_print(ndo, bp, len);
 107         break;
 108     case 0x3:
 109         ether_print(ndo, bp, len, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
 110         break;
 111     case 0x4:
 112         nsh_print(ndo, bp, len);
 113         break;
 114     default:
 115         ND_PRINT("ERROR: unknown-next-protocol");
 116         goto invalid;
 117     }
 118
 119         return;
 120
 121 invalid:
 122     nd_print_invalid(ndo);
 123 }
 124