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   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 #include "netdissect.h"
  27 #include "addrtoname.h"
  28 #include "extract.h"
  29
  30
  31 #define DTP_HEADER_LEN                  1
  32 #define DTP_DOMAIN_TLV                  0x0001
  33 #define DTP_STATUS_TLV                  0x0002
  34 #define DTP_DTP_TYPE_TLV                0x0003
  35 #define DTP_NEIGHBOR_TLV                0x0004
  36
  37 static const struct tok dtp_tlv_values[] = {
  38     { DTP_DOMAIN_TLV, "Domain TLV"},
  39     { DTP_STATUS_TLV, "Status TLV"},
  40     { DTP_DTP_TYPE_TLV, "DTP type TLV"},
  41     { DTP_NEIGHBOR_TLV, "Neighbor TLV"},
  42     { 0, NULL}
  43 };
  44
  45 void
  46 dtp_print (netdissect_options *ndo, const u_char *pptr, u_int length)
  47 {
  48     int type, len;
  49     const u_char *tptr;
  50
  51     ndo->ndo_protocol = "dtp";
  52     if (length < DTP_HEADER_LEN)
  53         goto trunc;
  54
  55     tptr = pptr;
  56
  57     ND_TCHECK_LEN(tptr, DTP_HEADER_LEN);
  58
  59     ND_PRINT("DTPv%u, length %u",
  60            EXTRACT_U_1(tptr),
  61            length);
  62
  63     /*
  64      * In non-verbose mode, just print version.
  65      */
  66     if (ndo->ndo_vflag < 1) {
  67         return;
  68     }
  69
  70     tptr += DTP_HEADER_LEN;
  71
  72     while (tptr < (pptr+length)) {
  73
  74         ND_TCHECK_4(tptr);
  75         type = EXTRACT_BE_U_2(tptr);
  76         len  = EXTRACT_BE_U_2(tptr + 2);
  77        /* XXX: should not be but sometimes it is, see the test captures */
  78         if (type == 0)
  79             return;
  80         ND_PRINT("\n\t%s (0x%04x) TLV, length %u",
  81                tok2str(dtp_tlv_values, "Unknown", type),
  82                type, len);
  83
  84         /* infinite loop check */
  85         if (len < 4)
  86             goto invalid;
  87         ND_TCHECK_LEN(tptr, len);
  88
  89         switch (type) {
  90         case DTP_DOMAIN_TLV:
  91                 ND_PRINT(", ");
  92                 nd_printzp(ndo, tptr+4, len-4, pptr+length);
  93                 break;
  94
  95         case DTP_STATUS_TLV:
  96         case DTP_DTP_TYPE_TLV:
  97                 if (len < 5)
  98                     goto invalid;
  99                 ND_PRINT(", 0x%x", EXTRACT_U_1(tptr + 4));
 100                 break;
 101
 102         case DTP_NEIGHBOR_TLV:
 103                 if (len < 10)
 104                     goto invalid;
 105                 ND_PRINT(", %s", etheraddr_string(ndo, tptr+4));
 106                 break;
 107
 108         default:
 109             break;
 110         }
 111         tptr += len;
 112     }
 113
 114     return;
 115
 116  invalid:
 117     ND_PRINT("%s", istr);
 118     return;
 119  trunc:
 120     nd_print_trunc(ndo);
 121 }