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
  16  * http://www.ietf.org/internet-drafts/draft-foschiano-udld-02.txt
  17  *
  18  * Original code by Carles Kishimoto <carles.kishimoto@gmail.com>
  19  */
  20
  21 #define NETDISSECT_REWORKED
  22 #ifdef HAVE_CONFIG_H
  23 #include "config.h"
  24 #endif
  25
  26 #include <tcpdump-stdinc.h>
  27
  28 #include "interface.h"
  29 #include "extract.h"
  30
  31 #define UDLD_HEADER_LEN                 4
  32 #define UDLD_DEVICE_ID_TLV              0x0001
  33 #define UDLD_PORT_ID_TLV                0x0002
  34 #define UDLD_ECHO_TLV                   0x0003
  35 #define UDLD_MESSAGE_INTERVAL_TLV       0x0004
  36 #define UDLD_TIMEOUT_INTERVAL_TLV       0x0005
  37 #define UDLD_DEVICE_NAME_TLV            0x0006
  38 #define UDLD_SEQ_NUMBER_TLV             0x0007
  39
  40 static const struct tok udld_tlv_values[] = {
  41     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
  42     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
  43     { UDLD_ECHO_TLV, "Echo TLV"},
  44     { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
  45     { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
  46     { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
  47     { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
  48     { 0, NULL}
  49 };
  50
  51 static const struct tok udld_code_values[] = {
  52     { 0x00, "Reserved"},
  53     { 0x01, "Probe message"},
  54     { 0x02, "Echo message"},
  55     { 0x03, "Flush message"},
  56     { 0, NULL}
  57 };
  58
  59 static const struct tok udld_flags_values[] = {
  60     { 0x00, "RT"},
  61     { 0x01, "RSY"},
  62     { 0, NULL}
  63 };
  64
  65 /*
  66  *
  67  * 0                   1                   2                   3
  68  * 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
  69  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  70  * | Ver | Opcode  |     Flags     |           Checksum            |
  71  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  72  * |               List of TLVs (variable length list)             |
  73  * |                              ...                              |
  74  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  75  *
  76  */
  77
  78 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
  79 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
  80
  81 void
  82 udld_print (netdissect_options *ndo, const u_char *pptr, u_int length)
  83 {
  84     int code, type, len;
  85     const u_char *tptr;
  86
  87     if (length < UDLD_HEADER_LEN)
  88         goto trunc;
  89
  90     tptr = pptr;
  91
  92     if (!ND_TTEST2(*tptr, UDLD_HEADER_LEN))
  93         goto trunc;
  94
  95     code = UDLD_EXTRACT_OPCODE(*tptr);
  96
  97     ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
  98            UDLD_EXTRACT_VERSION(*tptr),
  99            tok2str(udld_code_values, "Reserved", code),
 100            code,
 101            bittok2str(udld_flags_values, "none", *(tptr+1)),
 102            *(tptr+1),
 103            length));
 104
 105     /*
 106      * In non-verbose mode, just print version and opcode type
 107      */
 108     if (ndo->ndo_vflag < 1) {
 109         return;
 110     }
 111
 112     ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2)));
 113
 114     tptr += UDLD_HEADER_LEN;
 115
 116     while (tptr < (pptr+length)) {
 117
 118         if (!ND_TTEST2(*tptr, 4))
 119             goto trunc;
 120
 121         type = EXTRACT_16BITS(tptr);
 122         len  = EXTRACT_16BITS(tptr+2);
 123         len -= 4;
 124         tptr += 4;
 125
 126         /* infinite loop check */
 127         if (type == 0 || len == 0) {
 128             return;
 129         }
 130
 131         ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
 132                tok2str(udld_tlv_values, "Unknown", type),
 133                type, len));
 134
 135         switch (type) {
 136         case UDLD_DEVICE_ID_TLV:
 137         case UDLD_PORT_ID_TLV:
 138         case UDLD_ECHO_TLV:
 139         case UDLD_DEVICE_NAME_TLV:
 140             ND_PRINT((ndo, ", %s", tptr));
 141             break;
 142
 143         case UDLD_MESSAGE_INTERVAL_TLV:
 144         case UDLD_TIMEOUT_INTERVAL_TLV:
 145             ND_PRINT((ndo, ", %us", (*tptr)));
 146             break;
 147
 148         case UDLD_SEQ_NUMBER_TLV:
 149             ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr)));
 150             break;
 151
 152         default:
 153             break;
 154         }
 155         tptr += len;
 156     }
 157
 158     return;
 159
 160  trunc:
 161     ND_PRINT((ndo, "[|udld]"));
 162 }
 163
 164 /*
 165  * Local Variables:
 166  * c-style: whitesmith
 167  * c-basic-offset: 4
 168  * End:
 169  */