xref: /freebsd/contrib/tcpdump/print-otv.c (revision dd41de95a84d979615a2ef11df6850622bf6184e)
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: Overlay Transport Virtualization (OTV) printer */
17 
18 /* specification: draft-hasmit-otv-04 */
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 /*
30  * OTV header, draft-hasmit-otv-04
31  *
32  *     0                   1                   2                   3
33  *     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
34  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
35  *     |R|R|R|R|I|R|R|R|           Overlay ID                          |
36  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
37  *     |          Instance ID                          | Reserved      |
38  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
39  */
40 
41 void
42 otv_print(netdissect_options *ndo, const u_char *bp, u_int len)
43 {
44     uint8_t flags;
45 
46     ND_PRINT((ndo, "OTV, "));
47     if (len < 8)
48         goto trunc;
49 
50     ND_TCHECK(*bp);
51     flags = *bp;
52     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
53     bp += 1;
54 
55     ND_TCHECK2(*bp, 3);
56     ND_PRINT((ndo, "overlay %u, ", EXTRACT_24BITS(bp)));
57     bp += 3;
58 
59     ND_TCHECK2(*bp, 3);
60     ND_PRINT((ndo, "instance %u\n", EXTRACT_24BITS(bp)));
61     bp += 3;
62 
63     /* Reserved */
64     ND_TCHECK(*bp);
65     bp += 1;
66 
67     ether_print(ndo, bp, len - 8, ndo->ndo_snapend - bp, NULL, NULL);
68     return;
69 
70 trunc:
71     ND_PRINT((ndo, " [|OTV]"));
72 }
73