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