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 1.9 2023/08/17 20:19:40 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 #define ND_LONGJMP_FROM_TCHECK 43 #include "netdissect.h" 44 #include "extract.h" 45 #include "mpls.h" 46 47 static const char *mpls_labelname[] = { 48 /*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL", 49 "implicit NULL", "rsvd", 50 /*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 51 /*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd", 52 /*15*/ "rsvd", 53 }; 54 55 enum mpls_packet_type { 56 PT_UNKNOWN, 57 PT_IPV4, 58 PT_IPV6, 59 PT_OSI 60 }; 61 62 /* 63 * RFC3032: MPLS label stack encoding 64 */ 65 void 66 mpls_print(netdissect_options *ndo, const u_char *bp, u_int length) 67 { 68 const u_char *p; 69 uint32_t label_entry; 70 uint16_t label_stack_depth = 0; 71 uint8_t first; 72 enum mpls_packet_type pt = PT_UNKNOWN; 73 74 ndo->ndo_protocol = "mpls"; 75 p = bp; 76 nd_print_protocol_caps(ndo); 77 do { 78 if (length < sizeof(label_entry)) 79 goto invalid; 80 label_entry = GET_BE_U_4(p); 81 ND_PRINT("%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(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]); 88 ND_PRINT(", tc %u", MPLS_TC(label_entry)); 89 if (MPLS_STACK(label_entry)) 90 ND_PRINT(", [S]"); 91 ND_PRINT(", 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 if (length < 1) { 138 /* nothing to print */ 139 return; 140 } 141 first = GET_U_1(p); 142 pt = 143 (first >= 0x45 && first <= 0x4f) ? PT_IPV4 : 144 (first >= 0x60 && first <= 0x6f) ? PT_IPV6 : 145 (first >= 0x81 && first <= 0x83) ? PT_OSI : 146 /* ok bail out - we did not figure out what it is*/ 147 PT_UNKNOWN; 148 } 149 150 /* 151 * Print the payload. 152 */ 153 switch (pt) { 154 case PT_UNKNOWN: 155 if (!ndo->ndo_suppress_default_print) 156 ND_DEFAULTPRINT(p, length); 157 break; 158 159 case PT_IPV4: 160 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 161 ip_print(ndo, p, length); 162 break; 163 164 case PT_IPV6: 165 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 166 ip6_print(ndo, p, length); 167 break; 168 169 case PT_OSI: 170 ND_PRINT(ndo->ndo_vflag ? "\n\t" : " "); 171 isoclns_print(ndo, p, length); 172 break; 173 } 174 return; 175 176 invalid: 177 nd_print_invalid(ndo); 178 ND_TCHECK_LEN(p, length); 179 } 180