The Tcpdump Group git mirrors - tcpdump/blob - print-otv.c

   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 #ifdef HAVE_CONFIG_H
  17 #include "config.h"
  18 #endif
  19
  20 #include <tcpdump-stdinc.h>
  21
  22 #include "netdissect.h"
  23 #include "extract.h"
  24
  25 /*
  26  * OTV header, draft-hasmit-otv-04
  27  *
  28  *     0                   1                   2                   3
  29  *     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
  30  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  31  *     |R|R|R|R|I|R|R|R|           Overlay ID                          |
  32  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  33  *     |          Instance ID                          | Reserved      |
  34  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  35  */
  36
  37 void
  38 otv_print(netdissect_options *ndo, const u_char *bp, u_int len)
  39 {
  40     u_int8_t flags;
  41     u_int32_t overlay_id;
  42     u_int32_t instance_id;
  43
  44     if (len < 8) {
  45         ND_PRINT((ndo, "[|OTV]"));
  46         return;
  47     }
  48
  49     flags = *bp;
  50     bp += 1;
  51
  52     overlay_id = EXTRACT_24BITS(bp);
  53     bp += 3;
  54
  55     instance_id = EXTRACT_24BITS(bp);
  56     bp += 4;
  57
  58     ND_PRINT((ndo, "OTV, "));
  59     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
  60     ND_PRINT((ndo, "overlay %u, ", overlay_id));
  61     ND_PRINT((ndo, "instance %u\n", instance_id));
  62
  63     ether_print(ndo, bp, len - 8, len - 8, NULL, NULL);
  64 }