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 #ifdef HAVE_CONFIG_H
  22 #include "config.h"
  23 #endif
  24
  25 #include <tcpdump-stdinc.h>
  26
  27 #include "netdissect.h"
  28 #include "extract.h"
  29
  30 #define UDLD_HEADER_LEN                 4
  31 #define UDLD_DEVICE_ID_TLV              0x0001
  32 #define UDLD_PORT_ID_TLV                0x0002
  33 #define UDLD_ECHO_TLV                   0x0003
  34 #define UDLD_MESSAGE_INTERVAL_TLV       0x0004
  35 #define UDLD_TIMEOUT_INTERVAL_TLV       0x0005
  36 #define UDLD_DEVICE_NAME_TLV            0x0006
  37 #define UDLD_SEQ_NUMBER_TLV             0x0007
  38
  39 static const struct tok udld_tlv_values[] = {
  40     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
  41     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
  42     { UDLD_ECHO_TLV, "Echo TLV"},
  43     { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
  44     { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
  45     { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
  46     { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
  47     { 0, NULL}
  48 };
  49
  50 static const struct tok udld_code_values[] = {
  51     { 0x00, "Reserved"},
  52     { 0x01, "Probe message"},
  53     { 0x02, "Echo message"},
  54     { 0x03, "Flush message"},
  55     { 0, NULL}
  56 };
  57
  58 static const struct tok udld_flags_values[] = {
  59     { 0x00, "RT"},
  60     { 0x01, "RSY"},
  61     { 0, NULL}
  62 };
  63
  64 /*
  65  *
  66  * 0                   1                   2                   3
  67  * 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
  68  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  69  * | Ver | Opcode  |     Flags     |           Checksum            |
  70  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  71  * |               List of TLVs (variable length list)             |
  72  * |                              ...                              |
  73  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  74  *
  75  */
  76
  77 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
  78 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
  79
  80 void
  81 udld_print (netdissect_options *ndo, const u_char *pptr, u_int length)
  82 {
  83     int code, type, len;
  84     const u_char *tptr;
  85
  86     if (length < UDLD_HEADER_LEN)
  87         goto trunc;
  88
  89     tptr = pptr;
  90
  91     ND_TCHECK2(*tptr, UDLD_HEADER_LEN);
  92
  93     code = UDLD_EXTRACT_OPCODE(*tptr);
  94
  95     ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
  96            UDLD_EXTRACT_VERSION(*tptr),
  97            tok2str(udld_code_values, "Reserved", code),
  98            code,
  99            bittok2str(udld_flags_values, "none", *(tptr+1)),
 100            *(tptr+1),
 101            length));
 102
 103     /*
 104      * In non-verbose mode, just print version and opcode type
 105      */
 106     if (ndo->ndo_vflag < 1) {
 107         return;
 108     }
 109
 110     ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2)));
 111
 112     tptr += UDLD_HEADER_LEN;
 113
 114     while (tptr < (pptr+length)) {
 115
 116         ND_TCHECK2(*tptr, 4);
 117
 118         type = EXTRACT_16BITS(tptr);
 119         len  = EXTRACT_16BITS(tptr+2);
 120         len -= 4;
 121         tptr += 4;
 122
 123         /* infinite loop check */
 124         if (type == 0 || len == 0) {
 125             return;
 126         }
 127
 128         ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u",
 129                tok2str(udld_tlv_values, "Unknown", type),
 130                type, len));
 131
 132         switch (type) {
 133         case UDLD_DEVICE_ID_TLV:
 134         case UDLD_PORT_ID_TLV:
 135         case UDLD_ECHO_TLV:
 136         case UDLD_DEVICE_NAME_TLV:
 137             ND_PRINT((ndo, ", %s", tptr));
 138             break;
 139
 140         case UDLD_MESSAGE_INTERVAL_TLV:
 141         case UDLD_TIMEOUT_INTERVAL_TLV:
 142             ND_PRINT((ndo, ", %us", (*tptr)));
 143             break;
 144
 145         case UDLD_SEQ_NUMBER_TLV:
 146             ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr)));
 147             break;
 148
 149         default:
 150             break;
 151         }
 152         tptr += len;
 153     }
 154
 155     return;
 156
 157  trunc:
 158     ND_PRINT((ndo, "[|udld]"));
 159 }
 160
 161 /*
 162  * Local Variables:
 163  * c-style: whitesmith
 164  * c-basic-offset: 4
 165  * End:
 166  */