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 #define ND_LONGJMP_FROM_TCHECK 38 #include "netdissect.h" 39 #include "extract.h" 40 #include "mpls.h" 41 42 static const char *mpls_labelname[] = { 43 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 44 "implicit NULL", "rsvd", 45 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 46 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 47 /*15*/ "rsvd", 48 }; 49 50 enum mpls_packet_type { 51 PT_UNKNOWN, 52 PT_IPV4, 53 PT_IPV6, 54 PT_OSI 55 }; 56 57 /* 58 * RFC3032: MPLS label stack encoding 59 */ 60 void 61 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 62 { 63 const u_char *p; 64 uint32_t label_entry; 65 uint16_t label_stack_depth = 0; 66 uint8_t first; 67 enum mpls_packet_type pt = PT_UNKNOWN; 68 69 ndo->ndo_protocol = "mpls"; 70 p = bp; 71 nd_print_protocol_caps(ndo); 72 do { 73 if (length < sizeof(label_entry)) 74 goto invalid; 75 label_entry = GET_BE_U_4(p); 76 ND_PRINT("%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(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]); 83 ND_PRINT(", exp %u", MPLS_EXP(label_entry)); 84 if (MPLS_STACK(label_entry)) 85 ND_PRINT(", [S]"); 86 ND_PRINT(", 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 if (length < 1) { 133 /* nothing to print */ 134 return; 135 } 136 first = GET_U_1(p); 137 pt = 138 (first >= 0x45 && first <= 0x4f) ? PT_IPV4 : 139 (first >= 0x60 && first <= 0x6f) ? PT_IPV6 : 140 (first >= 0x81 && first <= 0x83) ? PT_OSI : 141 /* ok bail out - we did not figure out what it is*/ 142 PT_UNKNOWN; 143 } 144 145 /* 146 * Print the payload. 147 */ 148 switch (pt) { 149 case PT_UNKNOWN: 150 if (!ndo->ndo_suppress_default_print) 151 ND_DEFAULTPRINT(p, length); 152 break; 153 154 case PT_IPV4: 155 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 156 ip_print(ndo, p, length); 157 break; 158 159 case PT_IPV6: 160 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 161 ip6_print(ndo, p, length); 162 break; 163 164 case PT_OSI: 165 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 166 isoclns_print(ndo, p, length); 167 break; 168 } 169 return; 170 171 invalid: 172 nd_print_invalid(ndo); 173 ND_TCHECK_LEN(p, length); 174 } 175