xref: /netbsd-src/external/bsd/tcpdump/dist/print-vxlan.c (revision 181254a7b1bdde6873432bffef2d2decc4b5c22f)
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 #include <sys/cdefs.h>
17 #ifndef lint
18 __RCSID("$NetBSD: print-vxlan.c,v 1.3 2017/02/05 04:05:05 spz Exp $");
19 #endif
20 
21 /* \summary: Virtual eXtensible Local Area Network (VXLAN) printer */
22 
23 /* specification: RFC 7348 */
24 
25 #ifdef HAVE_CONFIG_H
26 #include "config.h"
27 #endif
28 
29 #include <netdissect-stdinc.h>
30 
31 #include "netdissect.h"
32 #include "extract.h"
33 
34 static const char tstr[] = " [|VXLAN]";
35 
36 #define VXLAN_HDR_LEN 8
37 
38 /*
39  * VXLAN header, RFC7348
40  *               Virtual eXtensible Local Area Network (VXLAN): A Framework
41  *               for Overlaying Virtualized Layer 2 Networks over Layer 3 Networks
42  *
43  *     0                   1                   2                   3
44  *     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
45  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
46  *    |R|R|R|R|I|R|R|R|            Reserved                           |
47  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
48  *    |                VXLAN Network Identifier (VNI) |   Reserved    |
49  *    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
50  */
51 
52 void
53 vxlan_print(netdissect_options *ndo, const u_char *bp, u_int len)
54 {
55     uint8_t flags;
56     uint32_t vni;
57 
58     if (len < VXLAN_HDR_LEN)
59         goto trunc;
60 
61     ND_TCHECK2(*bp, VXLAN_HDR_LEN);
62 
63     flags = *bp;
64     bp += 4;
65 
66     vni = EXTRACT_24BITS(bp);
67     bp += 4;
68 
69     ND_PRINT((ndo, "VXLAN, "));
70     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
71     ND_PRINT((ndo, "vni %u\n", vni));
72 
73     ether_print(ndo, bp, len - VXLAN_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
74 
75     return;
76 
77 trunc:
78     ND_PRINT((ndo, "%s", tstr));
79 }
80