1 /* 2 * Copyright (C) 2001 WIDE Project. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 1. Redistributions of source code must retain the above copyright 8 * notice, this list of conditions and the following disclaimer. 9 * 2. Redistributions in binary form must reproduce the above copyright 10 * notice, this list of conditions and the following disclaimer in the 11 * documentation and/or other materials provided with the distribution. 12 * 3. Neither the name of the project nor the names of its contributors 13 * may be used to endorse or promote products derived from this software 14 * without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #include <sys/cdefs.h> 30 #ifndef lint 31 __RCSID("$NetBSD: print-mpls.c,v 1.8 2017/09/08 14:01:13 christos Exp $"); 32 #endif 33 34 /* \summary: Multi-Protocol Label Switching (MPLS) printer */ 35 36 #ifdef HAVE_CONFIG_H 37 #include "config.h" 38 #endif 39 40 #include <netdissect-stdinc.h> 41 42 #include "netdissect.h" 43 #include "extract.h" 44 #include "mpls.h" 45 46 static const char *mpls_labelname[] = { 47 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 48 "implicit NULL", "rsvd", 49 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 50 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 51 /*15*/ "rsvd", 52 }; 53 54 enum mpls_packet_type { 55 PT_UNKNOWN, 56 PT_IPV4, 57 PT_IPV6, 58 PT_OSI 59 }; 60 61 /* 62 * RFC3032: MPLS label stack encoding 63 */ 64 void 65 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 66 { 67 const u_char *p; 68 uint32_t label_entry; 69 uint16_t label_stack_depth = 0; 70 enum mpls_packet_type pt = PT_UNKNOWN; 71 72 p = bp; 73 ND_PRINT((ndo, "MPLS")); 74 do { 75 ND_TCHECK2(*p, sizeof(label_entry)); 76 if (length < sizeof(label_entry)) { 77 ND_PRINT((ndo, "[|MPLS], length %u", length)); 78 return; 79 } 80 label_entry = EXTRACT_32BITS(p); 81 ND_PRINT((ndo, "%s(label %u", 82 (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ", 83 MPLS_LABEL(label_entry))); 84 label_stack_depth++; 85 if (ndo->ndo_vflag && 86 MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) 87 ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)])); 88 ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry))); 89 if (MPLS_STACK(label_entry)) 90 ND_PRINT((ndo, ", [S]")); 91 ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry))); 92 93 p += sizeof(label_entry); 94 length -= sizeof(label_entry); 95 } while (!MPLS_STACK(label_entry)); 96 97 /* 98 * Try to figure out the packet type. 99 */ 100 switch (MPLS_LABEL(label_entry)) { 101 102 case 0: /* IPv4 explicit NULL label */ 103 case 3: /* IPv4 implicit NULL label */ 104 pt = PT_IPV4; 105 break; 106 107 case 2: /* IPv6 explicit NULL label */ 108 pt = PT_IPV6; 109 break; 110 111 default: 112 /* 113 * Generally there's no indication of protocol in MPLS label 114 * encoding. 115 * 116 * However, draft-hsmit-isis-aal5mux-00.txt describes a 117 * technique for encapsulating IS-IS and IP traffic on the 118 * same ATM virtual circuit; you look at the first payload 119 * byte to determine the network layer protocol, based on 120 * the fact that 121 * 122 * 1) the first byte of an IP header is 0x45-0x4f 123 * for IPv4 and 0x60-0x6f for IPv6; 124 * 125 * 2) the first byte of an OSI CLNP packet is 0x81, 126 * the first byte of an OSI ES-IS packet is 0x82, 127 * and the first byte of an OSI IS-IS packet is 128 * 0x83; 129 * 130 * so the network layer protocol can be inferred from the 131 * first byte of the packet, if the protocol is one of the 132 * ones listed above. 133 * 134 * Cisco sends control-plane traffic MPLS-encapsulated in 135 * this fashion. 136 */ 137 ND_TCHECK(*p); 138 if (length < 1) { 139 /* nothing to print */ 140 return; 141 } 142 switch(*p) { 143 144 case 0x45: 145 case 0x46: 146 case 0x47: 147 case 0x48: 148 case 0x49: 149 case 0x4a: 150 case 0x4b: 151 case 0x4c: 152 case 0x4d: 153 case 0x4e: 154 case 0x4f: 155 pt = PT_IPV4; 156 break; 157 158 case 0x60: 159 case 0x61: 160 case 0x62: 161 case 0x63: 162 case 0x64: 163 case 0x65: 164 case 0x66: 165 case 0x67: 166 case 0x68: 167 case 0x69: 168 case 0x6a: 169 case 0x6b: 170 case 0x6c: 171 case 0x6d: 172 case 0x6e: 173 case 0x6f: 174 pt = PT_IPV6; 175 break; 176 177 case 0x81: 178 case 0x82: 179 case 0x83: 180 pt = PT_OSI; 181 break; 182 183 default: 184 /* ok bail out - we did not figure out what it is*/ 185 break; 186 } 187 } 188 189 /* 190 * Print the payload. 191 */ 192 if (pt == PT_UNKNOWN) { 193 if (!ndo->ndo_suppress_default_print) 194 ND_DEFAULTPRINT(p, length); 195 return; 196 } 197 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " ")); 198 switch (pt) { 199 200 case PT_IPV4: 201 ip_print(ndo, p, length); 202 break; 203 204 case PT_IPV6: 205 ip6_print(ndo, p, length); 206 break; 207 208 case PT_OSI: 209 isoclns_print(ndo, p, length); 210 break; 211 212 default: 213 break; 214 } 215 return; 216 217 trunc: 218 ND_PRINT((ndo, "[|MPLS]")); 219 } 220 221 222 /* 223 * Local Variables: 224 * c-style: whitesmith 225 * c-basic-offset: 8 226 * End: 227 */ 228