print-vxlan.c revision 313537 
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
29static 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
47void
48vxlan_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
72trunc:
73    ND_PRINT((ndo, "%s", tstr));
74}
75