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 /* \summary: Multi-Protocol Label Switching (MPLS) printer */ 30 31 #ifdef HAVE_CONFIG_H 32 #include "config.h" 33 #endif 34 35 #include <netdissect-stdinc.h> 36 37 #include "netdissect.h" 38 #include "extract.h" 39 #include "mpls.h" 40 41 static const char *mpls_labelname[] = { 42 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 43 "implicit NULL", "rsvd", 44 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 45 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 46 /*15*/ "rsvd", 47 }; 48 49 enum mpls_packet_type { 50 PT_UNKNOWN, 51 PT_IPV4, 52 PT_IPV6, 53 PT_OSI 54 }; 55 56 /* 57 * RFC3032: MPLS label stack encoding 58 */ 59 void 60 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 61 { 62 const u_char *p; 63 uint32_t label_entry; 64 uint16_t label_stack_depth = 0; 65 enum mpls_packet_type pt = PT_UNKNOWN; 66 67 p = bp; 68 ND_PRINT((ndo, "MPLS")); 69 do { 70 ND_TCHECK2(*p, sizeof(label_entry)); 71 if (length < sizeof(label_entry)) { 72 ND_PRINT((ndo, "[|MPLS], length %u", length)); 73 return; 74 } 75 label_entry = EXTRACT_32BITS(p); 76 ND_PRINT((ndo, "%s(label %u", 77 (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ", 78 MPLS_LABEL(label_entry))); 79 label_stack_depth++; 80 if (ndo->ndo_vflag && 81 MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) 82 ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)])); 83 ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry))); 84 if (MPLS_STACK(label_entry)) 85 ND_PRINT((ndo, ", [S]")); 86 ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry))); 87 88 p += sizeof(label_entry); 89 length -= sizeof(label_entry); 90 } while (!MPLS_STACK(label_entry)); 91 92 /* 93 * Try to figure out the packet type. 94 */ 95 switch (MPLS_LABEL(label_entry)) { 96 97 case 0: /* IPv4 explicit NULL label */ 98 case 3: /* IPv4 implicit NULL label */ 99 pt = PT_IPV4; 100 break; 101 102 case 2: /* IPv6 explicit NULL label */ 103 pt = PT_IPV6; 104 break; 105 106 default: 107 /* 108 * Generally there's no indication of protocol in MPLS label 109 * encoding. 110 * 111 * However, draft-hsmit-isis-aal5mux-00.txt describes a 112 * technique for encapsulating IS-IS and IP traffic on the 113 * same ATM virtual circuit; you look at the first payload 114 * byte to determine the network layer protocol, based on 115 * the fact that 116 * 117 * 1) the first byte of an IP header is 0x45-0x4f 118 * for IPv4 and 0x60-0x6f for IPv6; 119 * 120 * 2) the first byte of an OSI CLNP packet is 0x81, 121 * the first byte of an OSI ES-IS packet is 0x82, 122 * and the first byte of an OSI IS-IS packet is 123 * 0x83; 124 * 125 * so the network layer protocol can be inferred from the 126 * first byte of the packet, if the protocol is one of the 127 * ones listed above. 128 * 129 * Cisco sends control-plane traffic MPLS-encapsulated in 130 * this fashion. 131 */ 132 ND_TCHECK(*p); 133 if (length < 1) { 134 /* nothing to print */ 135 return; 136 } 137 switch(*p) { 138 139 case 0x45: 140 case 0x46: 141 case 0x47: 142 case 0x48: 143 case 0x49: 144 case 0x4a: 145 case 0x4b: 146 case 0x4c: 147 case 0x4d: 148 case 0x4e: 149 case 0x4f: 150 pt = PT_IPV4; 151 break; 152 153 case 0x60: 154 case 0x61: 155 case 0x62: 156 case 0x63: 157 case 0x64: 158 case 0x65: 159 case 0x66: 160 case 0x67: 161 case 0x68: 162 case 0x69: 163 case 0x6a: 164 case 0x6b: 165 case 0x6c: 166 case 0x6d: 167 case 0x6e: 168 case 0x6f: 169 pt = PT_IPV6; 170 break; 171 172 case 0x81: 173 case 0x82: 174 case 0x83: 175 pt = PT_OSI; 176 break; 177 178 default: 179 /* ok bail out - we did not figure out what it is*/ 180 break; 181 } 182 } 183 184 /* 185 * Print the payload. 186 */ 187 if (pt == PT_UNKNOWN) { 188 if (!ndo->ndo_suppress_default_print) 189 ND_DEFAULTPRINT(p, length); 190 return; 191 } 192 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " ")); 193 switch (pt) { 194 195 case PT_IPV4: 196 ip_print(ndo, p, length); 197 break; 198 199 case PT_IPV6: 200 ip6_print(ndo, p, length); 201 break; 202 203 case PT_OSI: 204 isoclns_print(ndo, p, length); 205 break; 206 207 default: 208 break; 209 } 210 return; 211 212 trunc: 213 ND_PRINT((ndo, "[|MPLS]")); 214 } 215 216 217 /* 218 * Local Variables: 219 * c-style: whitesmith 220 * c-basic-offset: 8 221 * End: 222 */ 223
