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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 static const char tstr[] = " [|dtp]";
  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 TLV"},
  40     { DTP_STATUS_TLV, "Status TLV"},
  41     { DTP_DTP_TYPE_TLV, "DTP type TLV"},
  42     { DTP_NEIGHBOR_TLV, "Neighbor TLV"},
  43     { 0, NULL}
  44 };
  45
  46 void
  47 dtp_print (netdissect_options *ndo, const u_char *pptr, u_int length)
  48 {
  49     int type, len;
  50     const u_char *tptr;
  51
  52     ndo->ndo_protocol = "dtp";
  53     if (length < DTP_HEADER_LEN)
  54         goto trunc;
  55
  56     tptr = pptr;
  57
  58     ND_TCHECK_LEN(tptr, DTP_HEADER_LEN);
  59
  60     ND_PRINT("DTPv%u, length %u",
  61            EXTRACT_U_1(tptr),
  62            length);
  63
  64     /*
  65      * In non-verbose mode, just print version.
  66      */
  67     if (ndo->ndo_vflag < 1) {
  68         return;
  69     }
  70
  71     tptr += DTP_HEADER_LEN;
  72
  73     while (tptr < (pptr+length)) {
  74
  75         ND_TCHECK_4(tptr);
  76         type = EXTRACT_BE_U_2(tptr);
  77         len  = EXTRACT_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)
  87             goto invalid;
  88         ND_TCHECK_LEN(tptr, len);
  89
  90         switch (type) {
  91         case DTP_DOMAIN_TLV:
  92                 ND_PRINT(", ");
  93                 fn_printzp(ndo, tptr+4, len-4, pptr+length);
  94                 break;
  95
  96         case DTP_STATUS_TLV:
  97         case DTP_DTP_TYPE_TLV:
  98                 if (len < 5)
  99                     goto invalid;
 100                 ND_PRINT(", 0x%x", EXTRACT_U_1(tptr + 4));
 101                 break;
 102
 103         case DTP_NEIGHBOR_TLV:
 104                 if (len < 10)
 105                     goto invalid;
 106                 ND_PRINT(", %s", etheraddr_string(ndo, tptr+4));
 107                 break;
 108
 109         default:
 110             break;
 111         }
 112         tptr += len;
 113     }
 114
 115     return;
 116
 117  invalid:
 118     ND_PRINT("%s", istr);
 119     return;
 120  trunc:
 121     ND_PRINT("%s", tstr);
 122 }