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#define ND_LONGJMP_FROM_TCHECK
27#include "netdissect.h"
28#include "extract.h"
29
30static const struct tok vxlan_flags [] = {
31    { 0x08, "I" },
32    { 0, NULL }
33};
34#define VXLAN_HDR_LEN 8
35
36/*
37 * VXLAN header, RFC7348
38 *               Virtual eXtensible Local Area Network (VXLAN): A Framework
39 *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
40 *
41 *     0                   1                   2                   3
42 *     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
43 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
44 *    |R|R|R|R|I|R|R|R|            Reserved                           |
45 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46 *    |                VXLAN Network Identifier (VNI) |   Reserved    |
47 *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48 */
49
50void
51vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
52{
53    uint8_t flags;
54    uint32_t vni;
55
56    ndo->ndo_protocol = "vxlan";
57    nd_print_protocol_caps(ndo);
58    if (len < VXLAN_HDR_LEN)
59        goto invalid;
60
61    flags = GET_U_1(bp);
62    bp += 1;
63    ND_PRINT(", flags [%s] (0x%02x), ",
64             bittok2str_nosep(vxlan_flags, "invalid", flags), flags);
65
66    /* 1st Reserved */
67    bp += 3;
68
69    vni = GET_BE_U_3(bp);
70    bp += 3;
71    ND_PRINT("vni %u\n", vni);
72
73    /* 2nd Reserved */
74    ND_TCHECK_1(bp);
75    bp += 1;
76
77    ether_print(ndo, bp, len - VXLAN_HDR_LEN, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
78
79    return;
80
81invalid:
82    nd_print_invalid(ndo);
83}
84