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401 lines
12 KiB
C
401 lines
12 KiB
C
/* Copyright (C) 2014-2021 Open Information Security Foundation
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*
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* You can copy, redistribute or modify this Program under the terms of
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* the GNU General Public License version 2 as published by the Free
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* Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* version 2 along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA.
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*/
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/**
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* \file
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*
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* \author Jason Ish <jason.ish@emulex.com>
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*
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* MPLS decoder.
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*/
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#include "suricata-common.h"
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#include "decode.h"
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#include "util-validate.h"
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#include "util-unittest.h"
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#define MPLS_HEADER_LEN 4
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#define MPLS_PW_LEN 4
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#define MPLS_MAX_RESERVED_LABEL 15
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#define MPLS_LABEL_IPV4 0
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#define MPLS_LABEL_ROUTER_ALERT 1
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#define MPLS_LABEL_IPV6 2
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#define MPLS_LABEL_NULL 3
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#define MPLS_LABEL(shim) SCNtohl(shim) >> 12
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#define MPLS_BOTTOM(shim) ((SCNtohl(shim) >> 8) & 0x1)
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/* Inner protocol guessing values. */
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#define MPLS_PROTO_ETHERNET_PW 0
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#define MPLS_PROTO_IPV4 4
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#define MPLS_PROTO_IPV6 6
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int DecodeMPLS(ThreadVars *tv, DecodeThreadVars *dtv, Packet *p,
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const uint8_t *pkt, uint32_t len)
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{
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DEBUG_VALIDATE_BUG_ON(pkt == NULL);
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uint32_t shim;
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int label;
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int event = 0;
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StatsIncr(tv, dtv->counter_mpls);
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if (!PacketIncreaseCheckLayers(p)) {
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return TM_ECODE_FAILED;
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}
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do {
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if (len < MPLS_HEADER_LEN) {
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ENGINE_SET_INVALID_EVENT(p, MPLS_HEADER_TOO_SMALL);
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return TM_ECODE_FAILED;
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}
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memcpy(&shim, pkt, sizeof(shim));
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pkt += MPLS_HEADER_LEN;
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len -= MPLS_HEADER_LEN;
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} while (MPLS_BOTTOM(shim) == 0);
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label = MPLS_LABEL(shim);
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if (label == MPLS_LABEL_IPV4) {
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if (len > USHRT_MAX) {
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return TM_ECODE_FAILED;
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}
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return DecodeIPV4(tv, dtv, p, pkt, len);
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}
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else if (label == MPLS_LABEL_ROUTER_ALERT) {
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/* Not valid at the bottom of the stack. */
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event = MPLS_BAD_LABEL_ROUTER_ALERT;
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}
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else if (label == MPLS_LABEL_IPV6) {
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if (len > USHRT_MAX) {
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return TM_ECODE_FAILED;
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}
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return DecodeIPV6(tv, dtv, p, pkt, len);
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}
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else if (label == MPLS_LABEL_NULL) {
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/* Shouldn't appear on the wire. */
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event = MPLS_BAD_LABEL_IMPLICIT_NULL;
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}
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else if (label < MPLS_MAX_RESERVED_LABEL) {
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event = MPLS_BAD_LABEL_RESERVED;
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}
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if (event) {
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goto end;
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}
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// Make sure we still have enough data. While we only need 1 byte to test
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// for IPv4 and IPv4, we need for to check for ethernet.
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if (len < MPLS_PW_LEN) {
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ENGINE_SET_INVALID_EVENT(p, MPLS_PKT_TOO_SMALL);
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return TM_ECODE_FAILED;
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}
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/* Best guess at inner packet. */
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switch (pkt[0] >> 4) {
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case MPLS_PROTO_IPV4:
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if (len > USHRT_MAX) {
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return TM_ECODE_FAILED;
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}
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DecodeIPV4(tv, dtv, p, pkt, len);
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break;
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case MPLS_PROTO_IPV6:
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if (len > USHRT_MAX) {
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return TM_ECODE_FAILED;
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}
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DecodeIPV6(tv, dtv, p, pkt, len);
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break;
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case MPLS_PROTO_ETHERNET_PW:
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DecodeEthernet(tv, dtv, p, pkt + MPLS_PW_LEN, len - MPLS_PW_LEN);
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break;
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default:
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ENGINE_SET_INVALID_EVENT(p, MPLS_UNKNOWN_PAYLOAD_TYPE);
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return TM_ECODE_OK;
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}
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end:
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if (event) {
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ENGINE_SET_EVENT(p, event);
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}
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return TM_ECODE_OK;
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}
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#ifdef UNITTESTS
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static int DecodeMPLSTestHeaderTooSmall(void)
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{
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int ret = 1;
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/* A packet that is too small to have a complete MPLS header. */
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uint8_t pkt[] = {
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0x00, 0x00, 0x11
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};
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Packet *p = SCMalloc(SIZE_OF_PACKET);
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if (unlikely(p == NULL)) {
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return 0;
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}
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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memset(p, 0, SIZE_OF_PACKET);
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DecodeMPLS(&tv, &dtv, p, pkt, sizeof(pkt));
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if (!ENGINE_ISSET_EVENT(p, MPLS_HEADER_TOO_SMALL)) {
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ret = 0;
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}
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SCFree(p);
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return ret;
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}
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static int DecodeMPLSTestPacketTooSmall(void)
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{
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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Packet *p0 = SCCalloc(1, SIZE_OF_PACKET);
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memset(p0, 0, SIZE_OF_PACKET);
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uint8_t pkt0[] = { 0x00, 0x01, 0x51, 0xff };
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DecodeMPLS(&tv, &dtv, p0, pkt0, sizeof(pkt0));
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FAIL_IF_NOT(ENGINE_ISSET_EVENT(p0, MPLS_PKT_TOO_SMALL));
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SCFree(p0);
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Packet *p1 = SCCalloc(1, SIZE_OF_PACKET);
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FAIL_IF_NULL(p1);
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uint8_t pkt1[] = { 0x00, 0x01, 0x51, 0xff, 0x45 };
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DecodeMPLS(&tv, &dtv, p1, pkt1, sizeof(pkt1));
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FAIL_IF_NOT(ENGINE_ISSET_EVENT(p1, MPLS_PKT_TOO_SMALL));
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SCFree(p1);
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Packet *p2 = SCCalloc(1, SIZE_OF_PACKET);
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FAIL_IF_NULL(p2);
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uint8_t pkt2[] = { 0x00, 0x01, 0x51, 0xff, 0x45, 0x01 };
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DecodeMPLS(&tv, &dtv, p2, pkt2, sizeof(pkt2));
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FAIL_IF_NOT(ENGINE_ISSET_EVENT(p2, MPLS_PKT_TOO_SMALL));
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SCFree(p2);
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Packet *p3 = SCCalloc(1, SIZE_OF_PACKET);
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FAIL_IF_NULL(p3);
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uint8_t pkt3[] = { 0x00, 0x01, 0x51, 0xff, 0x45, 0x01, 0x02 };
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DecodeMPLS(&tv, &dtv, p3, pkt3, sizeof(pkt3));
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FAIL_IF_NOT(ENGINE_ISSET_EVENT(p3, MPLS_PKT_TOO_SMALL));
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SCFree(p3);
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// This should not create a too small event is it has one more byte
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// than required.
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Packet *p4 = SCCalloc(1, SIZE_OF_PACKET);
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FAIL_IF_NULL(p4);
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uint8_t pkt4[] = { 0x00, 0x01, 0x51, 0xff, 0x45, 0x01, 0x02, 0x03 };
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DecodeMPLS(&tv, &dtv, p4, pkt4, sizeof(pkt4));
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FAIL_IF(ENGINE_ISSET_EVENT(p4, MPLS_PKT_TOO_SMALL));
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SCFree(p4);
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PASS;
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}
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static int DecodeMPLSTestBadLabelRouterAlert(void)
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{
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int ret = 1;
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uint8_t pkt[] = {
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0x00, 0x00, 0x11, 0xff, 0x45, 0x00, 0x00, 0x64,
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0x00, 0x0a, 0x00, 0x00, 0xff, 0x01, 0xa5, 0x6a,
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0x0a, 0x01, 0x02, 0x01, 0x0a, 0x22, 0x00, 0x01,
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0x08, 0x00, 0x3a, 0x77, 0x0a, 0x39, 0x06, 0x2b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x33, 0x50,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd
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};
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Packet *p = SCMalloc(SIZE_OF_PACKET);
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if (unlikely(p == NULL)) {
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return 0;
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}
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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memset(p, 0, SIZE_OF_PACKET);
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DecodeMPLS(&tv, &dtv, p, pkt, sizeof(pkt));
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if (!ENGINE_ISSET_EVENT(p, MPLS_BAD_LABEL_ROUTER_ALERT)) {
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ret = 0;
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}
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SCFree(p);
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return ret;
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}
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static int DecodeMPLSTestBadLabelImplicitNull(void)
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{
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int ret = 1;
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uint8_t pkt[] = {
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0x00, 0x00, 0x31, 0xff, 0x45, 0x00, 0x00, 0x64,
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0x00, 0x0a, 0x00, 0x00, 0xff, 0x01, 0xa5, 0x6a,
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0x0a, 0x01, 0x02, 0x01, 0x0a, 0x22, 0x00, 0x01,
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0x08, 0x00, 0x3a, 0x77, 0x0a, 0x39, 0x06, 0x2b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x33, 0x50,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd
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};
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Packet *p = SCMalloc(SIZE_OF_PACKET);
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if (unlikely(p == NULL)) {
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return 0;
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}
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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memset(p, 0, SIZE_OF_PACKET);
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DecodeMPLS(&tv, &dtv, p, pkt, sizeof(pkt));
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if (!ENGINE_ISSET_EVENT(p, MPLS_BAD_LABEL_IMPLICIT_NULL)) {
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ret = 0;
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}
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SCFree(p);
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return ret;
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}
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static int DecodeMPLSTestBadLabelReserved(void)
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{
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int ret = 1;
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uint8_t pkt[] = {
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0x00, 0x00, 0x51, 0xff, 0x45, 0x00, 0x00, 0x64,
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0x00, 0x0a, 0x00, 0x00, 0xff, 0x01, 0xa5, 0x6a,
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0x0a, 0x01, 0x02, 0x01, 0x0a, 0x22, 0x00, 0x01,
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0x08, 0x00, 0x3a, 0x77, 0x0a, 0x39, 0x06, 0x2b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x33, 0x50,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd
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};
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Packet *p = SCMalloc(SIZE_OF_PACKET);
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if (unlikely(p == NULL)) {
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return 0;
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}
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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memset(p, 0, SIZE_OF_PACKET);
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DecodeMPLS(&tv, &dtv, p, pkt, sizeof(pkt));
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if (!ENGINE_ISSET_EVENT(p, MPLS_BAD_LABEL_RESERVED)) {
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ret = 0;
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}
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SCFree(p);
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return ret;
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}
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static int DecodeMPLSTestUnknownPayloadType(void)
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{
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int ret = 1;
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/* Valid label: 21.
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* Unknown payload type: 1.
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*/
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uint8_t pkt[] = {
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0x00, 0x01, 0x51, 0xff, 0x15, 0x00, 0x00, 0x64,
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0x00, 0x0a, 0x00, 0x00, 0xff, 0x01, 0xa5, 0x6a,
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0x0a, 0x01, 0x02, 0x01, 0x0a, 0x22, 0x00, 0x01,
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0x08, 0x00, 0x3a, 0x77, 0x0a, 0x39, 0x06, 0x2b,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x1f, 0x33, 0x50,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd,
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0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd, 0xab, 0xcd
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};
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Packet *p = SCMalloc(SIZE_OF_PACKET);
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if (unlikely(p == NULL)) {
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return 0;
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}
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ThreadVars tv;
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DecodeThreadVars dtv;
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memset(&dtv, 0, sizeof(DecodeThreadVars));
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memset(&tv, 0, sizeof(ThreadVars));
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memset(p, 0, SIZE_OF_PACKET);
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DecodeMPLS(&tv, &dtv, p, pkt, sizeof(pkt));
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if (!ENGINE_ISSET_EVENT(p, MPLS_UNKNOWN_PAYLOAD_TYPE)) {
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ret = 0;
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}
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SCFree(p);
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return ret;
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}
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#endif /* UNITTESTS */
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void DecodeMPLSRegisterTests(void)
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{
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#ifdef UNITTESTS
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UtRegisterTest("DecodeMPLSTestHeaderTooSmall",
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DecodeMPLSTestHeaderTooSmall);
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UtRegisterTest("DecodeMPLSTestPacketTooSmall",
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DecodeMPLSTestPacketTooSmall);
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UtRegisterTest("DecodeMPLSTestBadLabelRouterAlert",
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DecodeMPLSTestBadLabelRouterAlert);
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UtRegisterTest("DecodeMPLSTestBadLabelImplicitNull",
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DecodeMPLSTestBadLabelImplicitNull);
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UtRegisterTest("DecodeMPLSTestBadLabelReserved",
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DecodeMPLSTestBadLabelReserved);
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UtRegisterTest("DecodeMPLSTestUnknownPayloadType",
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DecodeMPLSTestUnknownPayloadType);
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#endif /* UNITTESTS */
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}
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