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 /* \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 #define OTV_HDR_LEN 8
  30
  31 /*
  32  * OTV header, draft-hasmit-otv-04
  33  *
  34  *     0                   1                   2                   3
  35  *     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
  36  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  37  *     |R|R|R|R|I|R|R|R|           Overlay ID                          |
  38  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  39  *     |          Instance ID                          | Reserved      |
  40  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  41  */
  42
  43 void
  44 otv_print(netdissect_options *ndo, const u_char *bp, u_int len)
  45 {
  46     uint8_t flags;
  47
  48     ND_PRINT((ndo, "OTV, "));
  49     if (len < OTV_HDR_LEN)
  50         goto trunc;
  51
  52     ND_TCHECK(*bp);
  53     flags = *bp;
  54     ND_PRINT((ndo, "flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags));
  55     bp += 1;
  56
  57     ND_TCHECK2(*bp, 3);
  58     ND_PRINT((ndo, "overlay %u, ", EXTRACT_BE_U_3(bp)));
  59     bp += 3;
  60
  61     ND_TCHECK2(*bp, 3);
  62     ND_PRINT((ndo, "instance %u\n", EXTRACT_BE_U_3(bp)));
  63     bp += 3;
  64
  65     /* Reserved */
  66     ND_TCHECK(*bp);
  67     bp += 1;
  68
  69     ether_print(ndo, bp, len - OTV_HDR_LEN, ndo->ndo_snapend - bp, NULL, NULL);
  70     return;
  71
  72 trunc:
  73     ND_PRINT((ndo, " [|OTV]"));
  74 }