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

   1 /*
   2  * Redistribution and use in source and binary forms, with or without
   3  * modification, are permitted provided that: (1) source code
   4  * distributions retain the above copyright notice and this paragraph
   5  * in its entirety, and (2) distributions including binary code include
   6  * the above copyright notice and this paragraph in its entirety in
   7  * the documentation or other materials provided with the distribution.
   8  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
   9  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  10  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  11  * FOR A PARTICULAR PURPOSE.
  12  *
  13  * Original code by Francesco Fondelli (francesco dot fondelli, gmail dot com)
  14  */
  15
  16 /* \summary: Virtual eXtensible Local Area Network (VXLAN) printer */
  17
  18 /* specification: RFC 7348 */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include "netdissect-stdinc.h"
  25
  26 #include "netdissect.h"
  27 #include "extract.h"
  28
  29 static const struct tok vxlan_flags [] = {
  30     { 0x08, "I" },
  31     { 0, NULL }
  32 };
  33 #define VXLAN_HDR_LEN 8
  34
  35 /*
  36  * VXLAN header, RFC7348
  37  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
  38  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
  39  *
  40  *     0                   1                   2                   3
  41  *     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
  42  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  43  *    |R|R|R|R|I|R|R|R|            Reserved                           |
  44  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  46  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  47  */
  48
  49 void
  50 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
  51 {
  52     uint8_t flags;
  53     uint32_t vni;
  54
  55     ndo->ndo_protocol = "vxlan";
  56     if (len < VXLAN_HDR_LEN)
  57         goto trunc;
  58
  59     ND_TCHECK_LEN(bp, VXLAN_HDR_LEN);
  60
  61     flags = GET_U_1(bp);
  62     bp += 4;
  63
  64     vni = GET_BE_U_3(bp);
  65     bp += 4;
  66
  67     nd_print_protocol_caps(ndo);
  68     ND_PRINT(", flags [%s] (0x%02x), ",
  69              bittok2str_nosep(vxlan_flags, "invalid", flags), flags);
  70     ND_PRINT("vni %u\n", vni);
  71
  72     ether_print(ndo, bp, len - VXLAN_HDR_LEN, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
  73
  74     return;
  75
  76 trunc:
  77     nd_print_trunc(ndo);
  78 }