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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  * 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 (at) 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 "addrtoname.h"
     32 #include "extract.h"
     33 #include "nlpid.h"
     34 
     35 #define UDLD_HEADER_LEN			4
     36 #define UDLD_DEVICE_ID_TLV		0x0001
     37 #define UDLD_PORT_ID_TLV		0x0002
     38 #define UDLD_ECHO_TLV			0x0003
     39 #define UDLD_MESSAGE_INTERVAL_TLV	0x0004
     40 #define UDLD_TIMEOUT_INTERVAL_TLV	0x0005
     41 #define UDLD_DEVICE_NAME_TLV		0x0006
     42 #define UDLD_SEQ_NUMBER_TLV		0x0007
     43 
     44 static const struct tok udld_tlv_values[] = {
     45     { UDLD_DEVICE_ID_TLV, "Device-ID TLV"},
     46     { UDLD_PORT_ID_TLV, "Port-ID TLV"},
     47     { UDLD_ECHO_TLV, "Echo TLV"},
     48     { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"},
     49     { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"},
     50     { UDLD_DEVICE_NAME_TLV, "Device Name TLV"},
     51     { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"},
     52     { 0, NULL}
     53 };
     54 
     55 static const struct tok udld_code_values[] = {
     56     { 0x00, "Reserved"},
     57     { 0x01, "Probe message"},
     58     { 0x02, "Echo message"},
     59     { 0x03, "Flush message"},
     60     { 0, NULL}
     61 };
     62 
     63 static const struct tok udld_flags_values[] = {
     64     { 0x00, "RT"},
     65     { 0x01, "RSY"},
     66     { 0, NULL}
     67 };
     68 
     69 /*
     70  *
     71  * 0                   1                   2                   3
     72  * 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
     73  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     74  * | Ver | Opcode  |     Flags     |           Checksum            |
     75  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     76  * |               List of TLVs (variable length list)             |
     77  * |                              ...                              |
     78  * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
     79  *
     80  */
     81 
     82 #define	UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5)
     83 #define	UDLD_EXTRACT_OPCODE(x) ((x)&0x1f)
     84 
     85 void
     86 udld_print (const u_char *pptr, u_int length)
     87 {
     88     int code, type, len;
     89     const u_char *tptr;
     90 
     91     if (length < UDLD_HEADER_LEN)
     92         goto trunc;
     93 
     94     tptr = pptr;
     95 
     96     if (!TTEST2(*tptr, UDLD_HEADER_LEN))
     97 	goto trunc;
     98 
     99     code = UDLD_EXTRACT_OPCODE(*tptr);
    100 
    101     printf("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u",
    102            UDLD_EXTRACT_VERSION(*tptr),
    103            tok2str(udld_code_values, "Reserved", code),
    104            code,
    105            bittok2str(udld_flags_values, "none", *(tptr+1)),
    106            *(tptr+1),
    107            length);
    108 
    109     /*
    110      * In non-verbose mode, just print version and opcode type
    111      */
    112     if (vflag < 1) {
    113 	return;
    114     }
    115 
    116     printf("\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2));
    117 
    118     tptr += UDLD_HEADER_LEN;
    119 
    120     while (tptr < (pptr+length)) {
    121 
    122         if (!TTEST2(*tptr, 4))
    123             goto trunc;
    124 
    125 	type = EXTRACT_16BITS(tptr);
    126         len  = EXTRACT_16BITS(tptr+2);
    127         len -= 4;
    128         tptr += 4;
    129 
    130         /* infinite loop check */
    131         if (type == 0 || len == 0) {
    132             return;
    133         }
    134 
    135         printf("\n\t%s (0x%04x) TLV, length %u",
    136                tok2str(udld_tlv_values, "Unknown", type),
    137                type, len);
    138 
    139         switch (type) {
    140         case UDLD_DEVICE_ID_TLV:
    141         case UDLD_PORT_ID_TLV:
    142         case UDLD_ECHO_TLV:
    143         case UDLD_DEVICE_NAME_TLV:
    144             printf(", %s", tptr);
    145             break;
    146 
    147         case UDLD_MESSAGE_INTERVAL_TLV:
    148         case UDLD_TIMEOUT_INTERVAL_TLV:
    149             printf(", %us", (*tptr));
    150             break;
    151 
    152         case UDLD_SEQ_NUMBER_TLV:
    153             printf(", %u", EXTRACT_32BITS(tptr));
    154             break;
    155 
    156         default:
    157             break;
    158         }
    159         tptr += len;
    160     }
    161 
    162     return;
    163 
    164  trunc:
    165     printf("[|udld]");
    166 }
    167 
    168 /*
    169  * Local Variables:
    170  * c-style: whitesmith
    171  * c-basic-offset: 4
    172  * End:
    173  */
    174