211 lines
5.1 KiB
C
Executable File
211 lines
5.1 KiB
C
Executable File
/*
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* Copyright (C) 2001 WIDE Project. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the project nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include <tcpdump-stdinc.h>
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#include "interface.h"
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#include "extract.h" /* must come after interface.h */
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#include "mpls.h"
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static const char *mpls_labelname[] = {
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/*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
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"implicit NULL", "rsvd",
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/*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
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/*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
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/*15*/ "rsvd",
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};
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enum mpls_packet_type {
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PT_UNKNOWN,
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PT_IPV4,
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PT_IPV6,
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PT_OSI
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};
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/*
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* RFC3032: MPLS label stack encoding
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*/
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void
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mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
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{
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const u_char *p;
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uint32_t label_entry;
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uint16_t label_stack_depth = 0;
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enum mpls_packet_type pt = PT_UNKNOWN;
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p = bp;
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ND_PRINT((ndo, "MPLS"));
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do {
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ND_TCHECK2(*p, sizeof(label_entry));
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label_entry = EXTRACT_32BITS(p);
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ND_PRINT((ndo, "%s(label %u",
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(label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
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MPLS_LABEL(label_entry)));
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label_stack_depth++;
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if (ndo->ndo_vflag &&
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MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
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ND_PRINT((ndo, " (%s)", mpls_labelname[MPLS_LABEL(label_entry)]));
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ND_PRINT((ndo, ", exp %u", MPLS_EXP(label_entry)));
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if (MPLS_STACK(label_entry))
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ND_PRINT((ndo, ", [S]"));
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ND_PRINT((ndo, ", ttl %u)", MPLS_TTL(label_entry)));
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p += sizeof(label_entry);
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} while (!MPLS_STACK(label_entry));
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/*
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* Try to figure out the packet type.
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*/
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switch (MPLS_LABEL(label_entry)) {
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case 0: /* IPv4 explicit NULL label */
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case 3: /* IPv4 implicit NULL label */
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pt = PT_IPV4;
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break;
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case 2: /* IPv6 explicit NULL label */
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pt = PT_IPV6;
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break;
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default:
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/*
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* Generally there's no indication of protocol in MPLS label
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* encoding.
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*
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* However, draft-hsmit-isis-aal5mux-00.txt describes a
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* technique for encapsulating IS-IS and IP traffic on the
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* same ATM virtual circuit; you look at the first payload
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* byte to determine the network layer protocol, based on
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* the fact that
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*
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* 1) the first byte of an IP header is 0x45-0x4f
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* for IPv4 and 0x60-0x6f for IPv6;
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*
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* 2) the first byte of an OSI CLNP packet is 0x81,
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* the first byte of an OSI ES-IS packet is 0x82,
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* and the first byte of an OSI IS-IS packet is
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* 0x83;
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*
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* so the network layer protocol can be inferred from the
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* first byte of the packet, if the protocol is one of the
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* ones listed above.
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*
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* Cisco sends control-plane traffic MPLS-encapsulated in
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* this fashion.
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*/
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switch(*p) {
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case 0x45:
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case 0x46:
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case 0x47:
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case 0x48:
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case 0x49:
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case 0x4a:
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case 0x4b:
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case 0x4c:
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case 0x4d:
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case 0x4e:
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case 0x4f:
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pt = PT_IPV4;
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break;
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case 0x60:
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case 0x61:
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case 0x62:
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case 0x63:
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case 0x64:
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case 0x65:
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case 0x66:
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case 0x67:
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case 0x68:
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case 0x69:
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case 0x6a:
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case 0x6b:
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case 0x6c:
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case 0x6d:
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case 0x6e:
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case 0x6f:
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pt = PT_IPV6;
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break;
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case 0x81:
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case 0x82:
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case 0x83:
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pt = PT_OSI;
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break;
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default:
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/* ok bail out - we did not figure out what it is*/
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break;
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}
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}
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/*
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* Print the payload.
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*/
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if (pt == PT_UNKNOWN) {
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if (!ndo->ndo_suppress_default_print)
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ND_DEFAULTPRINT(p, length - (p - bp));
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return;
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}
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ND_PRINT((ndo, ndo->ndo_vflag ? "\n\t" : " "));
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switch (pt) {
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case PT_IPV4:
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ip_print(ndo, p, length - (p - bp));
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break;
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case PT_IPV6:
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ip6_print(ndo, p, length - (p - bp));
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break;
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case PT_OSI:
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isoclns_print(ndo, p, length - (p - bp), length - (p - bp));
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break;
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default:
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break;
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}
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return;
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trunc:
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ND_PRINT((ndo, "[|MPLS]"));
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}
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/*
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* Local Variables:
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* c-style: whitesmith
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* c-basic-offset: 8
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* End:
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*/
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