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 * Original code by Carles Kishimoto <carles.kishimoto@gmail.com> 16 */ 17 18 /* \summary: Cisco UniDirectional Link Detection (UDLD) protocol printer */ 19 20 /* specification: RFC 5171 */ 21 22 #ifdef HAVE_CONFIG_H 23 #include "config.h" 24 #endif 25 26 #include <netdissect-stdinc.h> 27 28 #include "netdissect.h" 29 #include "extract.h" 30 31 static const char tstr[] = " [|udld]"; 32 33 #define UDLD_HEADER_LEN 4 34 #define UDLD_DEVICE_ID_TLV 0x0001 35 #define UDLD_PORT_ID_TLV 0x0002 36 #define UDLD_ECHO_TLV 0x0003 37 #define UDLD_MESSAGE_INTERVAL_TLV 0x0004 38 #define UDLD_TIMEOUT_INTERVAL_TLV 0x0005 39 #define UDLD_DEVICE_NAME_TLV 0x0006 40 #define UDLD_SEQ_NUMBER_TLV 0x0007 41 42 static const struct tok udld_tlv_values[] = { 43 { UDLD_DEVICE_ID_TLV, "Device-ID TLV"}, 44 { UDLD_PORT_ID_TLV, "Port-ID TLV"}, 45 { UDLD_ECHO_TLV, "Echo TLV"}, 46 { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"}, 47 { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"}, 48 { UDLD_DEVICE_NAME_TLV, "Device Name TLV"}, 49 { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"}, 50 { 0, NULL} 51 }; 52 53 static const struct tok udld_code_values[] = { 54 { 0x00, "Reserved"}, 55 { 0x01, "Probe message"}, 56 { 0x02, "Echo message"}, 57 { 0x03, "Flush message"}, 58 { 0, NULL} 59 }; 60 61 static const struct tok udld_flags_values[] = { 62 { 0x00, "RT"}, 63 { 0x01, "RSY"}, 64 { 0, NULL} 65 }; 66 67 /* 68 * UDLD's Protocol Data Unit format: 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 * TLV format: 80 * 81 * 0 1 2 3 82 * 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 83 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 84 * | TYPE | LENGTH | 85 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 86 * | VALUE | 87 * | ... | 88 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 89 * 90 * LENGTH: Length in bytes of the Type, Length, and Value fields. 91 */ 92 93 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5) 94 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f) 95 96 void 97 udld_print (netdissect_options *ndo, const u_char *pptr, u_int length) 98 { 99 int code, type, len; 100 const u_char *tptr; 101 102 if (length < UDLD_HEADER_LEN) 103 goto trunc; 104 105 tptr = pptr; 106 107 ND_TCHECK2(*tptr, UDLD_HEADER_LEN); 108 109 code = UDLD_EXTRACT_OPCODE(*tptr); 110 111 ND_PRINT((ndo, "UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u", 112 UDLD_EXTRACT_VERSION(*tptr), 113 tok2str(udld_code_values, "Reserved", code), 114 code, 115 bittok2str(udld_flags_values, "none", *(tptr+1)), 116 *(tptr+1), 117 length)); 118 119 /* 120 * In non-verbose mode, just print version and opcode type 121 */ 122 if (ndo->ndo_vflag < 1) { 123 return; 124 } 125 126 ND_PRINT((ndo, "\n\tChecksum 0x%04x (unverified)", EXTRACT_16BITS(tptr+2))); 127 128 tptr += UDLD_HEADER_LEN; 129 130 while (tptr < (pptr+length)) { 131 132 ND_TCHECK2(*tptr, 4); 133 type = EXTRACT_16BITS(tptr); 134 len = EXTRACT_16BITS(tptr+2); 135 136 ND_PRINT((ndo, "\n\t%s (0x%04x) TLV, length %u", 137 tok2str(udld_tlv_values, "Unknown", type), 138 type, len)); 139 140 if (type == 0) 141 goto invalid; 142 143 /* infinite loop check */ 144 if (len <= 4) 145 goto invalid; 146 147 len -= 4; 148 tptr += 4; 149 150 ND_TCHECK2(*tptr, len); 151 152 switch (type) { 153 case UDLD_DEVICE_ID_TLV: 154 case UDLD_PORT_ID_TLV: 155 case UDLD_DEVICE_NAME_TLV: 156 ND_PRINT((ndo, ", ")); 157 fn_printzp(ndo, tptr, len, NULL); 158 break; 159 160 case UDLD_ECHO_TLV: 161 ND_PRINT((ndo, ", ")); 162 (void)fn_printn(ndo, tptr, len, NULL); 163 break; 164 165 case UDLD_MESSAGE_INTERVAL_TLV: 166 case UDLD_TIMEOUT_INTERVAL_TLV: 167 if (len != 1) 168 goto invalid; 169 ND_PRINT((ndo, ", %us", (*tptr))); 170 break; 171 172 case UDLD_SEQ_NUMBER_TLV: 173 if (len != 4) 174 goto invalid; 175 ND_PRINT((ndo, ", %u", EXTRACT_32BITS(tptr))); 176 break; 177 178 default: 179 break; 180 } 181 tptr += len; 182 } 183 184 return; 185 186 invalid: 187 ND_PRINT((ndo, "%s", istr)); 188 return; 189 trunc: 190 ND_PRINT((ndo, "%s", tstr)); 191 } 192 193 /* 194 * Local Variables: 195 * c-style: whitesmith 196 * c-basic-offset: 4 197 * End: 198 */ 199