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 1.10 2024/09/02 16:15:32 christos Exp $"); 32 #endif 33 34 /* \summary: Multi-Protocol Label Switching (MPLS) printer */ 35 36 #include <config.h> 37 38 #include "netdissect-stdinc.h" 39 40 #define ND_LONGJMP_FROM_TCHECK 41 #include "netdissect.h" 42 #include "extract.h" 43 #include "mpls.h" 44 45 static const char *mpls_labelname[] = { 46 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 47 "implicit NULL", "rsvd", 48 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 49 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 50 /*15*/ "rsvd", 51 }; 52 53 enum mpls_packet_type { 54 PT_UNKNOWN, 55 PT_IPV4, 56 PT_IPV6, 57 PT_OSI 58 }; 59 60 /* 61 * RFC3032: MPLS label stack encoding 62 */ 63 void 64 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 65 { 66 const u_char *p; 67 uint32_t label_entry; 68 uint16_t label_stack_depth = 0; 69 uint8_t first; 70 enum mpls_packet_type pt = PT_UNKNOWN; 71 72 ndo->ndo_protocol = "mpls"; 73 p = bp; 74 nd_print_protocol_caps(ndo); 75 do { 76 if (length < sizeof(label_entry)) 77 goto invalid; 78 label_entry = GET_BE_U_4(p); 79 ND_PRINT("%s(label %u", 80 (label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ", 81 MPLS_LABEL(label_entry)); 82 label_stack_depth++; 83 if (ndo->ndo_vflag && 84 MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0])) 85 ND_PRINT(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]); 86 ND_PRINT(", tc %u", MPLS_TC(label_entry)); 87 if (MPLS_STACK(label_entry)) 88 ND_PRINT(", [S]"); 89 ND_PRINT(", ttl %u)", MPLS_TTL(label_entry)); 90 91 p += sizeof(label_entry); 92 length -= sizeof(label_entry); 93 } while (!MPLS_STACK(label_entry)); 94 95 /* 96 * Try to figure out the packet type. 97 */ 98 switch (MPLS_LABEL(label_entry)) { 99 100 case 0: /* IPv4 explicit NULL label */ 101 case 3: /* IPv4 implicit NULL label */ 102 pt = PT_IPV4; 103 break; 104 105 case 2: /* IPv6 explicit NULL label */ 106 pt = PT_IPV6; 107 break; 108 109 default: 110 /* 111 * Generally there's no indication of protocol in MPLS label 112 * encoding. 113 * 114 * However, draft-hsmit-isis-aal5mux-00.txt describes a 115 * technique for encapsulating IS-IS and IP traffic on the 116 * same ATM virtual circuit; you look at the first payload 117 * byte to determine the network layer protocol, based on 118 * the fact that 119 * 120 * 1) the first byte of an IP header is 0x45-0x4f 121 * for IPv4 and 0x60-0x6f for IPv6; 122 * 123 * 2) the first byte of an OSI CLNP packet is 0x81, 124 * the first byte of an OSI ES-IS packet is 0x82, 125 * and the first byte of an OSI IS-IS packet is 126 * 0x83; 127 * 128 * so the network layer protocol can be inferred from the 129 * first byte of the packet, if the protocol is one of the 130 * ones listed above. 131 * 132 * Cisco sends control-plane traffic MPLS-encapsulated in 133 * this fashion. 134 */ 135 if (length < 1) { 136 /* nothing to print */ 137 return; 138 } 139 first = GET_U_1(p); 140 pt = 141 (first >= 0x45 && first <= 0x4f) ? PT_IPV4 : 142 (first >= 0x60 && first <= 0x6f) ? PT_IPV6 : 143 (first >= 0x81 && first <= 0x83) ? PT_OSI : 144 /* ok bail out - we did not figure out what it is*/ 145 PT_UNKNOWN; 146 } 147 148 /* 149 * Print the payload. 150 */ 151 switch (pt) { 152 case PT_UNKNOWN: 153 if (!ndo->ndo_suppress_default_print) 154 ND_DEFAULTPRINT(p, length); 155 break; 156 157 case PT_IPV4: 158 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 159 ip_print(ndo, p, length); 160 break; 161 162 case PT_IPV6: 163 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 164 ip6_print(ndo, p, length); 165 break; 166 167 case PT_OSI: 168 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 169 isoclns_print(ndo, p, length); 170 break; 171 } 172 return; 173 174 invalid: 175 nd_print_invalid(ndo); 176 ND_TCHECK_LEN(p, length); 177 } 178