contrib/tcpdump/print-dtp.c

   1 /*
   2  * Copyright (c) 1998-2007 The TCPDUMP project
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that: (1) source code
   6  * distributions retain the above copyright notice and this paragraph
   7  * in its entirety, and (2) distributions including binary code include
   8  * the above copyright notice and this paragraph in its entirety in
   9  * the documentation or other materials provided with the distribution.
  10  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND
  11  * WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, WITHOUT
  12  * LIMITATION, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  13  * FOR A PARTICULAR PURPOSE.
  14  *
  15  * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
  16  */
  17
  18 /* \summary: Dynamic Trunking Protocol (DTP) printer */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include <config.h>
  22 #endif
  23
  24 #include "netdissect-stdinc.h"
  25
  26 #define ND_LONGJMP_FROM_TCHECK
  27 #include "netdissect.h"
  28 #include "addrtoname.h"
  29 #include "extract.h"
  30
  31
  32 #define DTP_HEADER_LEN                  1
  33 #define DTP_DOMAIN_TLV                  0x0001
  34 #define DTP_STATUS_TLV                  0x0002
  35 #define DTP_DTP_TYPE_TLV                0x0003
  36 #define DTP_NEIGHBOR_TLV                0x0004
  37
  38 static const struct tok dtp_tlv_values[] = {
  39     { DTP_DOMAIN_TLV, "Domain" },
  40     { DTP_STATUS_TLV, "Status" },
  41     { DTP_DTP_TYPE_TLV, "DTP type" },
  42     { DTP_NEIGHBOR_TLV, "Neighbor" },
  43     { 0, NULL}
  44 };
  45
  46 void
  47 dtp_print(netdissect_options *ndo, const u_char *tptr, u_int length)
  48 {
  49     ndo->ndo_protocol = "dtp";
  50     if (length < DTP_HEADER_LEN) {
  51         ND_PRINT("[zero packet length]");
  52         goto invalid;
  53     }
  54
  55     ND_PRINT("DTPv%u, length %u",
  56            GET_U_1(tptr),
  57            length);
  58
  59     /*
  60      * In non-verbose mode, just print version.
  61      */
  62     if (ndo->ndo_vflag < 1) {
  63         return;
  64     }
  65
  66     tptr += DTP_HEADER_LEN;
  67     length -= DTP_HEADER_LEN;
  68
  69     while (length) {
  70         uint16_t type, len;
  71
  72         if (length < 4) {
  73             ND_PRINT("[%u bytes remaining]", length);
  74             goto invalid;
  75         }
  76         type = GET_BE_U_2(tptr);
  77         len  = GET_BE_U_2(tptr + 2);
  78        /* XXX: should not be but sometimes it is, see the test captures */
  79         if (type == 0)
  80             return;
  81         ND_PRINT("\n\t%s (0x%04x) TLV, length %u",
  82                tok2str(dtp_tlv_values, "Unknown", type),
  83                type, len);
  84
  85         /* infinite loop check */
  86         if (len < 4 || len > length) {
  87             ND_PRINT("[invalid TLV length %u]", len);
  88             goto invalid;
  89         }
  90
  91         switch (type) {
  92         case DTP_DOMAIN_TLV:
  93                 ND_PRINT(", ");
  94                 nd_printjnp(ndo, tptr+4, len-4);
  95                 break;
  96
  97         case DTP_STATUS_TLV:
  98         case DTP_DTP_TYPE_TLV:
  99                 if (len != 5)
 100                     goto invalid;
 101                 ND_PRINT(", 0x%x", GET_U_1(tptr + 4));
 102                 break;
 103
 104         case DTP_NEIGHBOR_TLV:
 105                 if (len != 10)
 106                     goto invalid;
 107                 ND_PRINT(", %s", GET_ETHERADDR_STRING(tptr+4));
 108                 break;
 109
 110         default:
 111             ND_TCHECK_LEN(tptr, len);
 112             break;
 113         }
 114         tptr += len;
 115         length -= len;
 116     }
 117     return;
 118
 119  invalid:
 120     nd_print_invalid(ndo);
 121     ND_TCHECK_LEN(tptr, length);
 122 }