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 <netdissect-stdinc.h>
  21
  22 #include "netdissect.h"
  23 #include "extract.h"
  24
  25 static const char tstr[] = " [|VXLAN]";
  26
  27 #define VXLAN_HDR_LEN 8
  28
  29 /*
  30  * VXLAN header, RFC7348
  31  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
  32  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
  33  *
  34  *     0                   1                   2                   3
  35  *     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
  36  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *    |R|R|R|R|I|R|R|R|            Reserved                           |
  38  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  40  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  */
  42
  43 void
  44 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
  45 {
  46     uint8_t flags;
  47     uint32_t vni;
  48
  49     if (len < VXLAN_HDR_LEN)
  50         goto trunc;
  51
  52     ND_TCHECK2(*bp, VXLAN_HDR_LEN);
  53
  54     flags = *bp;
  55     bp += 4;
  56
  57     vni = EXTRACT_24BITS(bp);
  58     bp += 4;
  59
  60     ND_PRINT((ndo, "VXLAN, "));
  61     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
  62     ND_PRINT((ndo, "vni %u\n", vni));
  63
  64     ether_print(ndo, bp, len - VXLAN_HDR_LEN, len - VXLAN_HDR_LEN, NULL, NULL);
  65
  66     return;
  67
  68 trunc:
  69     ND_PRINT((ndo, "%s", tstr));
  70 }