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 char tstr[] = " [|VXLAN]";
  30
  31 #define VXLAN_HDR_LEN 8
  32
  33 /*
  34  * VXLAN header, RFC7348
  35  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
  36  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
  37  *
  38  *     0                   1                   2                   3
  39  *     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
  40  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  *    |R|R|R|R|I|R|R|R|            Reserved                           |
  42  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  43  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
  44  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  45  */
  46
  47 void
  48 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
  49 {
  50     uint8_t flags;
  51     uint32_t vni;
  52
  53     if (len < VXLAN_HDR_LEN)
  54         goto trunc;
  55
  56     ND_TCHECK2(*bp, VXLAN_HDR_LEN);
  57
  58     flags = *bp;
  59     bp += 4;
  60
  61     vni = EXTRACT_24BITS(bp);
  62     bp += 4;
  63
  64     ND_PRINT((ndo, "VXLAN, "));
  65     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
  66     ND_PRINT((ndo, "vni %u\n", vni));
  67
  68     ether_print(ndo, bp, len - VXLAN_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
  69
  70     return;
  71
  72 trunc:
  73     ND_PRINT((ndo, "%s", tstr));
  74 }