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 #define NETDISSECT_REWORKED 30 #ifdef HAVE_CONFIG_H 31 #include "config.h" 32 #endif 33 34 #include <tcpdump-stdinc.h> 35 36 #include "interface.h" 37 #include "extract.h" /* must come after interface.h */ 38 #include "mpls.h" 39 40 static const char *mpls_labelname[] = { 41 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 42 "implicit NULL", "rsvd", 43 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 44 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 45 /*15*/ "rsvd", 46 }; 47 48 enum mpls_packet_type { 49 PT_UNKNOWN, 50 PT_IPV4, 51 PT_IPV6, 52 PT_OSI 53 }; 54 55 /* 56 * RFC3032: MPLS label stack encoding 57 */ 58 void 59 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 60 { 61 const u_char *p; 62 uint32_t label_entry; 63 uint16_t label_stack_depth = 0; 64 enum mpls_packet_type pt = PT_UNKNOWN; 65 66 p = bp; 67 ND_PRINT((ndo, "MPLS")); 68 do { 69 ND_TCHECK2(*p, sizeof(label_entry)); 70 label_entry = EXTRACT_32BITS(p); 71 ND_PRINT((ndo, "%s(label %u", 72 (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ", 73 MPLS_LABEL(label_entry))); 74 label_stack_depth++; 75 if (ndo->ndo_vflag && 76 MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) 77 ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)])); 78 ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry))); 79 if (MPLS_STACK(label_entry)) 80 ND_PRINT((ndo, ", [S]")); 81 ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry))); 82 83 p += sizeof(label_entry); 84 } while (!MPLS_STACK(label_entry)); 85 86 /* 87 * Try to figure out the packet type. 88 */ 89 switch (MPLS_LABEL(label_entry)) { 90 91 case 0: /* IPv4 explicit NULL label */ 92 case 3: /* IPv4 implicit NULL label */ 93 pt = PT_IPV4; 94 break; 95 96 case 2: /* IPv6 explicit NULL label */ 97 pt = PT_IPV6; 98 break; 99 100 default: 101 /* 102 * Generally there's no indication of protocol in MPLS label 103 * encoding. 104 * 105 * However, draft-hsmit-isis-aal5mux-00.txt describes a 106 * technique for encapsulating IS-IS and IP traffic on the 107 * same ATM virtual circuit; you look at the first payload 108 * byte to determine the network layer protocol, based on 109 * the fact that 110 * 111 * 1) the first byte of an IP header is 0x45-0x4f 112 * for IPv4 and 0x60-0x6f for IPv6; 113 * 114 * 2) the first byte of an OSI CLNP packet is 0x81, 115 * the first byte of an OSI ES-IS packet is 0x82, 116 * and the first byte of an OSI IS-IS packet is 117 * 0x83; 118 * 119 * so the network layer protocol can be inferred from the 120 * first byte of the packet, if the protocol is one of the 121 * ones listed above. 122 * 123 * Cisco sends control-plane traffic MPLS-encapsulated in 124 * this fashion. 125 */ 126 switch(*p) { 127 128 case 0x45: 129 case 0x46: 130 case 0x47: 131 case 0x48: 132 case 0x49: 133 case 0x4a: 134 case 0x4b: 135 case 0x4c: 136 case 0x4d: 137 case 0x4e: 138 case 0x4f: 139 pt = PT_IPV4; 140 break; 141 142 case 0x60: 143 case 0x61: 144 case 0x62: 145 case 0x63: 146 case 0x64: 147 case 0x65: 148 case 0x66: 149 case 0x67: 150 case 0x68: 151 case 0x69: 152 case 0x6a: 153 case 0x6b: 154 case 0x6c: 155 case 0x6d: 156 case 0x6e: 157 case 0x6f: 158 pt = PT_IPV6; 159 break; 160 161 case 0x81: 162 case 0x82: 163 case 0x83: 164 pt = PT_OSI; 165 break; 166 167 default: 168 /* ok bail out - we did not figure out what it is*/ 169 break; 170 } 171 } 172 173 /* 174 * Print the payload. 175 */ 176 if (pt == PT_UNKNOWN) { 177 if (!ndo->ndo_suppress_default_print) 178 ND_DEFAULTPRINT(p, length - (p - bp)); 179 return; 180 } 181 ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " ")); 182 switch (pt) { 183 184 case PT_IPV4: 185 ip_print(ndo, p, length - (p - bp)); 186 break; 187 188 case PT_IPV6: 189 ip6_print(ndo, p, length - (p - bp)); 190 break; 191 192 case PT_OSI: 193 isoclns_print(ndo, p, length - (p - bp), length - (p - bp)); 194 break; 195 196 default: 197 break; 198 } 199 return; 200 201 trunc: 202 ND_PRINT((ndo, "[|MPLS]")); 203 } 204 205 206 /* 207 * Local Variables: 208 * c-style: whitesmith 209 * c-basic-offset: 8 210 * End: 211 */ 212
