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/*
* Copyright (C) 2001 WIDE Project. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the project nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* \summary: Multi-Protocol Label Switching (MPLS) printer */
#include <config.h>
#include "netdissect-stdinc.h"
#define ND_LONGJMP_FROM_TCHECK
#include "netdissect.h"
#include "extract.h"
#include "mpls.h"
static const char *mpls_labelname[] = {
/*0*/ "IPv4 explicit NULL", "router alert", "IPv6 explicit NULL",
"implicit NULL", "rsvd",
/*5*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
/*10*/ "rsvd", "rsvd", "rsvd", "rsvd", "rsvd",
/*15*/ "rsvd",
};
enum mpls_packet_type {
PT_UNKNOWN,
PT_IPV4,
PT_IPV6,
PT_OSI
};
/*
* RFC3032: MPLS label stack encoding
*/
void
mpls_print(netdissect_options *ndo, const u_char *bp, u_int length)
{
const u_char *p;
uint32_t label_entry;
uint16_t label_stack_depth = 0;
uint8_t first;
enum mpls_packet_type pt = PT_UNKNOWN;
ndo->ndo_protocol = "mpls";
p = bp;
nd_print_protocol_caps(ndo);
do {
if (length < sizeof(label_entry))
goto invalid;
label_entry = GET_BE_U_4(p);
ND_PRINT("%s(label %u",
(label_stack_depth && ndo->ndo_vflag) ? "\n\t" : " ",
MPLS_LABEL(label_entry));
label_stack_depth++;
if (ndo->ndo_vflag &&
MPLS_LABEL(label_entry) < sizeof(mpls_labelname) / sizeof(mpls_labelname[0]))
ND_PRINT(" (%s)", mpls_labelname[MPLS_LABEL(label_entry)]);
ND_PRINT(", tc %u", MPLS_TC(label_entry));
if (MPLS_STACK(label_entry))
ND_PRINT(", [S]");
ND_PRINT(", ttl %u)", MPLS_TTL(label_entry));
p += sizeof(label_entry);
length -= sizeof(label_entry);
} while (!MPLS_STACK(label_entry));
/*
* Try to figure out the packet type.
*/
switch (MPLS_LABEL(label_entry)) {
case 0: /* IPv4 explicit NULL label */
case 3: /* IPv4 implicit NULL label */
pt = PT_IPV4;
break;
case 2: /* IPv6 explicit NULL label */
pt = PT_IPV6;
break;
default:
/*
* Generally there's no indication of protocol in MPLS label
* encoding.
*
* However, draft-hsmit-isis-aal5mux-00.txt describes a
* technique for encapsulating IS-IS and IP traffic on the
* same ATM virtual circuit; you look at the first payload
* byte to determine the network layer protocol, based on
* the fact that
*
* 1) the first byte of an IP header is 0x45-0x4f
* for IPv4 and 0x60-0x6f for IPv6;
*
* 2) the first byte of an OSI CLNP packet is 0x81,
* the first byte of an OSI ES-IS packet is 0x82,
* and the first byte of an OSI IS-IS packet is
* 0x83;
*
* so the network layer protocol can be inferred from the
* first byte of the packet, if the protocol is one of the
* ones listed above.
*
* Cisco sends control-plane traffic MPLS-encapsulated in
* this fashion.
*/
if (length < 1) {
/* nothing to print */
return;
}
first = GET_U_1(p);
pt =
(first >= 0x45 && first <= 0x4f) ? PT_IPV4 :
(first >= 0x60 && first <= 0x6f) ? PT_IPV6 :
(first >= 0x81 && first <= 0x83) ? PT_OSI :
/* ok bail out - we did not figure out what it is*/
PT_UNKNOWN;
}
/*
* Print the payload.
*/
switch (pt) {
case PT_UNKNOWN:
if (!ndo->ndo_suppress_default_print)
ND_DEFAULTPRINT(p, length);
break;
case PT_IPV4:
ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
ip_print(ndo, p, length);
break;
case PT_IPV6:
ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
ip6_print(ndo, p, length);
break;
case PT_OSI:
ND_PRINT(ndo->ndo_vflag ? "\n\t" : " ");
isoclns_print(ndo, p, length);
break;
}
return;
invalid:
nd_print_invalid(ndo);
ND_TCHECK_LEN(p, length);
}
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