The Tcpdump Group git mirrors - tcpdump/blob - print-udld.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  * UNIDIRECTIONAL LINK DETECTION (UDLD) as per RFC5171
  16  *
  17  * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
  18  */
  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 static const char tstr[] = " [|udld]";
  30 static const char istr[] = " (invalid)";
  31
  32 #define UDLD_HEADER_LEN                 4
  33 #define UDLD_DEVICE_ID_TLV              0x0001
  34 #define UDLD_PORT_ID_TLV                0x0002
  35 #define UDLD_ECHO_TLV                   0x0003
  36 #define UDLD_MESSAGE_INTERVAL_TLV       0x0004
  37 #define UDLD_TIMEOUT_INTERVAL_TLV       0x0005
  38 #define UDLD_DEVICE_NAME_TLV            0x0006
  39 #define UDLD_SEQ_NUMBER_TLV             0x0007
  40
  41 static const struct tok udld_tlv_values[] = {
  42     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
  43     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
  44     { UDLD_ECHO_TLV, "Echo TLV"},
  45     { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
  46     { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
  47     { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
  48     { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
  49     { 0, NULL}
  50 };
  51
  52 static const struct tok udld_code_values[] = {
  53     { 0x00, "Reserved"},
  54     { 0x01, "Probe message"},
  55     { 0x02, "Echo message"},
  56     { 0x03, "Flush message"},
  57     { 0, NULL}
  58 };
  59
  60 static const struct tok udld_flags_values[] = {
  61     { 0x00, "RT"},
  62     { 0x01, "RSY"},
  63     { 0, NULL}
  64 };
  65
  66 /*
  67  * UDLD's Protocol Data Unit format:
  68  *
  69  *  0                   1                   2                   3
  70  *  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
  71  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  72  * | Ver | Opcode  |     Flags     |           Checksum            |
  73  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  74  * |               List of TLVs (variable length list)             |
  75  * |                              ...                              |
  76  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  77  *
  78  * TLV format:
  79  *
  80  *  0                   1                   2                   3
  81  *  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
  82  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  83  * |             TYPE              |            LENGTH             |
  84  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  85  * |                             VALUE                             |
  86  * |                              ...                              |
  87  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  88  *
  89  * LENGTH: Length in bytes of the Type, Length, and Value fields.
  90  */
  91
  92 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
  93 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
  94
  95 void
  96 udld_print (netdissect_options *ndo, const u_char *pptr, u_int length)
  97 {
  98     int code, type, len;
  99     const u_char *tptr;
 100
 101     if (length < UDLD_HEADER_LEN)
 102         goto trunc;
 103
 104     tptr = pptr;
 105
 106     ND_TCHECK2(*tptr, UDLD_HEADER_LEN);
 107
 108     code = UDLD_EXTRACT_OPCODE(*tptr);
 109
 110     ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
 111            UDLD_EXTRACT_VERSION(*tptr),
 112            tok2str(udld_code_values, "Reserved", code),
 113            code,
 114            bittok2str(udld_flags_values, "none", *(tptr+1)),
 115            *(tptr+1),
 116            length));
 117
 118     /*
 119      * In non-verbose mode, just print version and opcode type
 120      */
 121     if (ndo->ndo_vflag < 1) {
 122         return;
 123     }
 124
 125     ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2)));
 126
 127     tptr += UDLD_HEADER_LEN;
 128
 129     while (tptr < (pptr+length)) {
 130
 131         ND_TCHECK2(*tptr, 4);
 132         type = EXTRACT_16BITS(tptr);
 133         len  = EXTRACT_16BITS(tptr+2);
 134
 135         ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
 136                tok2str(udld_tlv_values, "Unknown", type),
 137                type, len));
 138
 139         if (type == 0)
 140             goto invalid;
 141
 142         /* infinite loop check */
 143         if (len <= 4)
 144             goto invalid;
 145
 146         len -= 4;
 147         tptr += 4;
 148
 149         ND_TCHECK2(*tptr, len);
 150
 151         switch (type) {
 152         case UDLD_DEVICE_ID_TLV:
 153         case UDLD_PORT_ID_TLV:
 154         case UDLD_DEVICE_NAME_TLV:
 155             ND_PRINT((ndo, ", "));
 156             fn_printzp(ndo, tptr, len, NULL);
 157             break;
 158
 159         case UDLD_ECHO_TLV:
 160             ND_PRINT((ndo, ", "));
 161             fn_printn(ndo, tptr, len, NULL);
 162             break;
 163
 164         case UDLD_MESSAGE_INTERVAL_TLV:
 165         case UDLD_TIMEOUT_INTERVAL_TLV:
 166             if (len != 1)
 167                 goto invalid;
 168             ND_PRINT((ndo, ", %us", (*tptr)));
 169             break;
 170
 171         case UDLD_SEQ_NUMBER_TLV:
 172             if (len != 4)
 173                 goto invalid;
 174             ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr)));
 175             break;
 176
 177         default:
 178             break;
 179         }
 180         tptr += len;
 181     }
 182
 183     return;
 184
 185 invalid:
 186     ND_PRINT((ndo, "%s", istr));
 187     return;
 188 trunc:
 189     ND_PRINT((ndo, "%s", tstr));
 190 }
 191
 192 /*
 193  * Local Variables:
 194  * c-style: whitesmith
 195  * c-basic-offset: 4
 196  * End:
 197  */