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 <stdio.h>
  28 #include <string.h>
  29
  30 #include "interface.h"
  31 #include "extract.h"
  32 #include "nlpid.h"
  33
  34 #define UDLD_HEADER_LEN                 4
  35 #define UDLD_DEVICE_ID_TLV              0x0001
  36 #define UDLD_PORT_ID_TLV                0x0002
  37 #define UDLD_ECHO_TLV                   0x0003
  38 #define UDLD_MESSAGE_INTERVAL_TLV       0x0004
  39 #define UDLD_TIMEOUT_INTERVAL_TLV       0x0005
  40 #define UDLD_DEVICE_NAME_TLV            0x0006
  41 #define UDLD_SEQ_NUMBER_TLV             0x0007
  42
  43 static const struct tok udld_tlv_values[] = {
  44     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
  45     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
  46     { UDLD_ECHO_TLV, "Echo TLV"},
  47     { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
  48     { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
  49     { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
  50     { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
  51     { 0, NULL}
  52 };
  53
  54 static const struct tok udld_code_values[] = {
  55     { 0x00, "Reserved"},
  56     { 0x01, "Probe message"},
  57     { 0x02, "Echo message"},
  58     { 0x03, "Flush message"},
  59     { 0, NULL}
  60 };
  61
  62 static const struct tok udld_flags_values[] = {
  63     { 0x00, "RT"},
  64     { 0x01, "RSY"},
  65     { 0, NULL}
  66 };
  67
  68 /*
  69  *
  70  * 0                   1                   2                   3
  71  * 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
  72  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  73  * | Ver | Opcode  |     Flags     |           Checksum            |
  74  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  75  * |               List of TLVs (variable length list)             |
  76  * |                              ...                              |
  77  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  78  *
  79  */
  80
  81 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
  82 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
  83
  84 void
  85 udld_print (const u_char *pptr, u_int length)
  86 {
  87     int code, type, len;
  88     const u_char *tptr;
  89
  90     if (length < UDLD_HEADER_LEN)
  91         goto trunc;
  92
  93     tptr = pptr;
  94
  95     if (!TTEST2(*tptr, UDLD_HEADER_LEN))
  96         goto trunc;
  97
  98     code = UDLD_EXTRACT_OPCODE(*tptr);
  99
 100     printf("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
 101            UDLD_EXTRACT_VERSION(*tptr),
 102            tok2str(udld_code_values, "Reserved", code),
 103            code,
 104            bittok2str(udld_flags_values, "none", *(tptr+1)),
 105            *(tptr+1),
 106            length);
 107
 108     /*
 109      * In non-verbose mode, just print version and opcode type
 110      */
 111     if (vflag < 1) {
 112         return;
 113     }
 114
 115     printf("\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2));
 116
 117     tptr += UDLD_HEADER_LEN;
 118
 119     while (tptr < (pptr+length)) {
 120
 121         if (!TTEST2(*tptr, 4))
 122             goto trunc;
 123
 124         type = EXTRACT_16BITS(tptr);
 125         len  = EXTRACT_16BITS(tptr+2);
 126         len -= 4;
 127         tptr += 4;
 128
 129         /* infinite loop check */
 130         if (type == 0 || len == 0) {
 131             return;
 132         }
 133
 134         printf("\n\t%s (0x%04x) TLV, length %u",
 135                tok2str(udld_tlv_values, "Unknown", type),
 136                type, len);
 137
 138         switch (type) {
 139         case UDLD_DEVICE_ID_TLV:
 140         case UDLD_PORT_ID_TLV:
 141         case UDLD_ECHO_TLV:
 142         case UDLD_DEVICE_NAME_TLV:
 143             printf(", %s", tptr);
 144             break;
 145
 146         case UDLD_MESSAGE_INTERVAL_TLV:
 147         case UDLD_TIMEOUT_INTERVAL_TLV:
 148             printf(", %us", (*tptr));
 149             break;
 150
 151         case UDLD_SEQ_NUMBER_TLV:
 152             printf(", %u", EXTRACT_32BITS(tptr));
 153             break;
 154
 155         default:
 156             break;
 157         }
 158         tptr += len;
 159     }
 160
 161     return;
 162
 163  trunc:
 164     printf("[|udld]");
 165 }
 166
 167 /*
 168  * Local Variables:
 169  * c-style: whitesmith
 170  * c-basic-offset: 4
 171  * End:
 172  */