xref: /freebsd/contrib/tcpdump/print-vxlan.c (revision 0b3105a37d7adcadcb720112fed4dc4e8040be99)
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 #define NETDISSECT_REWORKED
17 #ifdef HAVE_CONFIG_H
18 #include "config.h"
19 #endif
20 
21 #include <tcpdump-stdinc.h>
22 
23 #include "interface.h"
24 #include "extract.h"
25 
26 /*
27  * VXLAN header, RFC7348
28  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
29  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
30  *
31  *     0                   1                   2                   3
32  *     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
33  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
34  *    |R|R|R|R|I|R|R|R|            Reserved                           |
35  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
36  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
37  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
38  */
39 
40 void
41 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
42 {
43     uint8_t flags;
44     uint32_t vni;
45 
46     if (len < 8) {
47         ND_PRINT((ndo, "[|VXLAN]"));
48         return;
49     }
50 
51     flags = *bp;
52     bp += 4;
53 
54     vni = EXTRACT_24BITS(bp);
55     bp += 4;
56 
57     ND_PRINT((ndo, "VXLAN, "));
58     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
59     ND_PRINT((ndo, "vni %u\n", vni));
60 
61     ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
62 }
63