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 #define ND_LONGJMP_FROM_TCHECK 29 #include "netdissect.h" 30 #include "extract.h" 31 32 33 #define UDLD_HEADER_LEN 4 34 #define UDLD_TLV_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_bitmap_str[] = { 63 { 1U << 0, "RT" }, 64 { 1U << 1, "RSY" }, 65 { 1U << 2, "MBZ-2" }, 66 { 1U << 3, "MBZ-3" }, 67 { 1U << 4, "MBZ-4" }, 68 { 1U << 5, "MBZ-5" }, 69 { 1U << 6, "MBZ-6" }, 70 { 1U << 7, "MBZ-7" }, 71 { 0, NULL} 72 }; 73 74 /* 75 * UDLD's Protocol Data Unit format: 76 * 77 * 0 1 2 3 78 * 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 79 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 80 * | Ver | Opcode | Flags | Checksum | 81 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 82 * | List of TLVs (variable length list) | 83 * | ... | 84 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 85 * 86 * TLV format: 87 * 88 * 0 1 2 3 89 * 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 90 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 91 * | TYPE | LENGTH | 92 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 93 * | VALUE | 94 * | ... | 95 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 96 * 97 * LENGTH: Length in bytes of the Type, Length, and Value fields. 98 */ 99 100 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5) 101 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f) 102 103 void 104 udld_print(netdissect_options *ndo, 105 const u_char *tptr, u_int length) 106 { 107 uint8_t ver, code, flags; 108 109 ndo->ndo_protocol = "udld"; 110 if (length < UDLD_HEADER_LEN) 111 goto invalid; 112 113 ver = UDLD_EXTRACT_VERSION(GET_U_1(tptr)); 114 code = UDLD_EXTRACT_OPCODE(GET_U_1(tptr)); 115 tptr += 1; 116 length -= 1; 117 118 flags = GET_U_1(tptr); 119 tptr += 1; 120 length -= 1; 121 122 ND_PRINT("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u", 123 ver, 124 tok2str(udld_code_values, "Reserved", code), 125 code, 126 bittok2str(udld_flags_bitmap_str, "none", flags), 127 flags, 128 length + 2); 129 130 /* 131 * In non-verbose mode, just print version and opcode type 132 */ 133 if (ndo->ndo_vflag < 1) { 134 goto tcheck_remainder; 135 } 136 137 ND_PRINT("\n\tChecksum 0x%04x (unverified)", GET_BE_U_2(tptr)); 138 tptr += 2; 139 length -= 2; 140 141 while (length) { 142 uint16_t type, len; 143 144 if (length < UDLD_TLV_HEADER_LEN) 145 goto invalid; 146 147 type = GET_BE_U_2(tptr); 148 tptr += 2; 149 length -= 2; 150 151 len = GET_BE_U_2(tptr); 152 tptr += 2; 153 length -= 2; 154 155 ND_PRINT("\n\t%s (0x%04x) TLV, length %u", 156 tok2str(udld_tlv_values, "Unknown", type), 157 type, len); 158 159 /* infinite loop check */ 160 if (len <= UDLD_TLV_HEADER_LEN) 161 goto invalid; 162 163 len -= UDLD_TLV_HEADER_LEN; 164 if (length < len) 165 goto invalid; 166 167 switch (type) { 168 case UDLD_DEVICE_ID_TLV: 169 case UDLD_PORT_ID_TLV: 170 case UDLD_DEVICE_NAME_TLV: 171 ND_PRINT(", "); 172 nd_printjnp(ndo, tptr, len); 173 break; 174 175 case UDLD_ECHO_TLV: 176 ND_PRINT(", "); 177 (void)nd_printn(ndo, tptr, len, NULL); 178 break; 179 180 case UDLD_MESSAGE_INTERVAL_TLV: 181 case UDLD_TIMEOUT_INTERVAL_TLV: 182 if (len != 1) 183 goto invalid; 184 ND_PRINT(", %us", (GET_U_1(tptr))); 185 break; 186 187 case UDLD_SEQ_NUMBER_TLV: 188 if (len != 4) 189 goto invalid; 190 ND_PRINT(", %u", GET_BE_U_4(tptr)); 191 break; 192 193 default: 194 ND_TCHECK_LEN(tptr, len); 195 break; 196 } 197 tptr += len; 198 length -= len; 199 } 200 201 return; 202 203 invalid: 204 nd_print_invalid(ndo); 205 tcheck_remainder: 206 ND_TCHECK_LEN(tptr, length); 207 } 208