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 #include <sys/cdefs.h> 23 #ifndef lint 24 __RCSID("$NetBSD: print-udld.c,v 1.4 2023/08/17 20:19:40 christos Exp $"); 25 #endif 26 27 #ifdef HAVE_CONFIG_H 28 #include <config.h> 29 #endif 30 31 #include "netdissect-stdinc.h" 32 33 #define ND_LONGJMP_FROM_TCHECK 34 #include "netdissect.h" 35 #include "extract.h" 36 37 38 #define UDLD_HEADER_LEN 4 39 #define UDLD_TLV_HEADER_LEN 4 40 #define UDLD_DEVICE_ID_TLV 0x0001 41 #define UDLD_PORT_ID_TLV 0x0002 42 #define UDLD_ECHO_TLV 0x0003 43 #define UDLD_MESSAGE_INTERVAL_TLV 0x0004 44 #define UDLD_TIMEOUT_INTERVAL_TLV 0x0005 45 #define UDLD_DEVICE_NAME_TLV 0x0006 46 #define UDLD_SEQ_NUMBER_TLV 0x0007 47 48 static const struct tok udld_tlv_values[] = { 49 { UDLD_DEVICE_ID_TLV, "Device-ID TLV"}, 50 { UDLD_PORT_ID_TLV, "Port-ID TLV"}, 51 { UDLD_ECHO_TLV, "Echo TLV"}, 52 { UDLD_MESSAGE_INTERVAL_TLV, "Message Interval TLV"}, 53 { UDLD_TIMEOUT_INTERVAL_TLV, "Timeout Interval TLV"}, 54 { UDLD_DEVICE_NAME_TLV, "Device Name TLV"}, 55 { UDLD_SEQ_NUMBER_TLV,"Sequence Number TLV"}, 56 { 0, NULL} 57 }; 58 59 static const struct tok udld_code_values[] = { 60 { 0x00, "Reserved"}, 61 { 0x01, "Probe message"}, 62 { 0x02, "Echo message"}, 63 { 0x03, "Flush message"}, 64 { 0, NULL} 65 }; 66 67 static const struct tok udld_flags_bitmap_str[] = { 68 { 1U << 0, "RT" }, 69 { 1U << 1, "RSY" }, 70 { 1U << 2, "MBZ-2" }, 71 { 1U << 3, "MBZ-3" }, 72 { 1U << 4, "MBZ-4" }, 73 { 1U << 5, "MBZ-5" }, 74 { 1U << 6, "MBZ-6" }, 75 { 1U << 7, "MBZ-7" }, 76 { 0, NULL} 77 }; 78 79 /* 80 * UDLD's Protocol Data Unit format: 81 * 82 * 0 1 2 3 83 * 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 84 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 85 * | Ver | Opcode | Flags | Checksum | 86 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 87 * | List of TLVs (variable length list) | 88 * | ... | 89 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 90 * 91 * TLV format: 92 * 93 * 0 1 2 3 94 * 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 95 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 96 * | TYPE | LENGTH | 97 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 98 * | VALUE | 99 * | ... | 100 * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 101 * 102 * LENGTH: Length in bytes of the Type, Length, and Value fields. 103 */ 104 105 #define UDLD_EXTRACT_VERSION(x) (((x)&0xe0)>>5) 106 #define UDLD_EXTRACT_OPCODE(x) ((x)&0x1f) 107 108 void 109 udld_print(netdissect_options *ndo, 110 const u_char *tptr, u_int length) 111 { 112 uint8_t ver, code, flags; 113 114 ndo->ndo_protocol = "udld"; 115 if (length < UDLD_HEADER_LEN) 116 goto invalid; 117 118 ver = UDLD_EXTRACT_VERSION(GET_U_1(tptr)); 119 code = UDLD_EXTRACT_OPCODE(GET_U_1(tptr)); 120 tptr += 1; 121 length -= 1; 122 123 flags = GET_U_1(tptr); 124 tptr += 1; 125 length -= 1; 126 127 ND_PRINT("UDLDv%u, Code %s (%x), Flags [%s] (0x%02x), length %u", 128 ver, 129 tok2str(udld_code_values, "Reserved", code), 130 code, 131 bittok2str(udld_flags_bitmap_str, "none", flags), 132 flags, 133 length + 2); 134 135 /* 136 * In non-verbose mode, just print version and opcode type 137 */ 138 if (ndo->ndo_vflag < 1) { 139 goto tcheck_remainder; 140 } 141 142 ND_PRINT("\n\tChecksum 0x%04x (unverified)", GET_BE_U_2(tptr)); 143 tptr += 2; 144 length -= 2; 145 146 while (length) { 147 uint16_t type, len; 148 149 if (length < UDLD_TLV_HEADER_LEN) 150 goto invalid; 151 152 type = GET_BE_U_2(tptr); 153 tptr += 2; 154 length -= 2; 155 156 len = GET_BE_U_2(tptr); 157 tptr += 2; 158 length -= 2; 159 160 ND_PRINT("\n\t%s (0x%04x) TLV, length %u", 161 tok2str(udld_tlv_values, "Unknown", type), 162 type, len); 163 164 /* infinite loop check */ 165 if (len <= UDLD_TLV_HEADER_LEN) 166 goto invalid; 167 168 len -= UDLD_TLV_HEADER_LEN; 169 if (length < len) 170 goto invalid; 171 172 switch (type) { 173 case UDLD_DEVICE_ID_TLV: 174 case UDLD_PORT_ID_TLV: 175 case UDLD_DEVICE_NAME_TLV: 176 ND_PRINT(", "); 177 nd_printjnp(ndo, tptr, len); 178 break; 179 180 case UDLD_ECHO_TLV: 181 ND_PRINT(", "); 182 (void)nd_printn(ndo, tptr, len, NULL); 183 break; 184 185 case UDLD_MESSAGE_INTERVAL_TLV: 186 case UDLD_TIMEOUT_INTERVAL_TLV: 187 if (len != 1) 188 goto invalid; 189 ND_PRINT(", %us", (GET_U_1(tptr))); 190 break; 191 192 case UDLD_SEQ_NUMBER_TLV: 193 if (len != 4) 194 goto invalid; 195 ND_PRINT(", %u", GET_BE_U_4(tptr)); 196 break; 197 198 default: 199 ND_TCHECK_LEN(tptr, len); 200 break; 201 } 202 tptr += len; 203 length -= len; 204 } 205 206 return; 207 208 invalid: 209 nd_print_invalid(ndo); 210 tcheck_remainder: 211 ND_TCHECK_LEN(tptr, length); 212 } 213