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 #ifdef HAVE_CONFIG_H
  17 #include "config.h"
  18 #endif
  19
  20 #include <tcpdump-stdinc.h>
  21
  22 #include "interface.h"
  23 #include "extract.h"
  24
  25 /*
  26  * VXLAN header, RFC7348
  27  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
  28  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
  29  *
  30  *     0                   1                   2                   3
  31  *     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
  32  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *    |R|R|R|R|I|R|R|R|            Reserved                           |
  34  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  36  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  */
  38
  39 void
  40 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
  41 {
  42     uint8_t flags;
  43     uint32_t vni;
  44
  45     if (len < 8) {
  46         ND_PRINT((ndo, "[|VXLAN]"));
  47         return;
  48     }
  49
  50     flags = *bp;
  51     bp += 4;
  52
  53     vni = EXTRACT_24BITS(bp);
  54     bp += 4;
  55
  56     ND_PRINT((ndo, "VXLAN, "));
  57     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
  58     ND_PRINT((ndo, "vni %u\n", vni));
  59
  60     ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
  61 }