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 #include <config.h>
  21
  22 #include "netdissect-stdinc.h"
  23
  24 #define ND_LONGJMP_FROM_TCHECK
  25 #include "netdissect.h"
  26 #include "extract.h"
  27
  28 #define OTV_HDR_LEN 8
  29
  30 /*
  31  * OTV header, draft-hasmit-otv-04
  32  *
  33  *     0                   1                   2                   3
  34  *     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
  35  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  36  *     |R|R|R|R|I|R|R|R|           Overlay ID                          |
  37  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  38  *     |          Instance ID                          | Reserved      |
  39  *     +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  40  */
  41
  42 void
  43 otv_print(netdissect_options *ndo, const u_char *bp, u_int len)
  44 {
  45     uint8_t flags;
  46
  47     ndo->ndo_protocol = "otv";
  48     ND_PRINT("OTV, ");
  49     if (len < OTV_HDR_LEN) {
  50         ND_PRINT("[length %u < %u]", len, OTV_HDR_LEN);
  51         goto invalid;
  52     }
  53
  54     flags = GET_U_1(bp);
  55     ND_PRINT("flags [%s] (0x%02x), ", flags & 0x08 ? "I" : ".", flags);
  56     bp += 1;
  57
  58     ND_PRINT("overlay %u, ", GET_BE_U_3(bp));
  59     bp += 3;
  60
  61     ND_PRINT("instance %u\n", GET_BE_U_3(bp));
  62     bp += 3;
  63
  64     /* Reserved */
  65     ND_TCHECK_1(bp);
  66     bp += 1;
  67
  68     ether_print(ndo, bp, len - OTV_HDR_LEN, ND_BYTES_AVAILABLE_AFTER(bp), NULL, NULL);
  69     return;
  70
  71 invalid:
  72     nd_print_invalid(ndo);
  73     ND_TCHECK_LEN(bp, len);
  74 }