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mpls_ttl.c revision 1.2.2.2
      1  1.2.2.2  rmind /*	$NetBSD: mpls_ttl.c,v 1.2.2.2 2010/07/03 01:20:00 rmind Exp $ */
      2  1.2.2.2  rmind 
      3  1.2.2.2  rmind /*
      4  1.2.2.2  rmind  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      5  1.2.2.2  rmind  * All rights reserved.
      6  1.2.2.2  rmind  *
      7  1.2.2.2  rmind  * Redistribution and use in source and binary forms, with or without
      8  1.2.2.2  rmind  * modification, are permitted provided that the following conditions
      9  1.2.2.2  rmind  * are met:
     10  1.2.2.2  rmind  * 1. Redistributions of source code must retain the above copyright
     11  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer.
     12  1.2.2.2  rmind  * 2. Redistributions in binary form must reproduce the above copyright
     13  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer in the
     14  1.2.2.2  rmind  *    documentation and/or other materials provided with the distribution.
     15  1.2.2.2  rmind  * 3. Neither the name of the project nor the names of its contributors
     16  1.2.2.2  rmind  *    may be used to endorse or promote products derived from this software
     17  1.2.2.2  rmind  *    without specific prior written permission.
     18  1.2.2.2  rmind  *
     19  1.2.2.2  rmind  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     20  1.2.2.2  rmind  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  1.2.2.2  rmind  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  1.2.2.2  rmind  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     23  1.2.2.2  rmind  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  1.2.2.2  rmind  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  1.2.2.2  rmind  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  1.2.2.2  rmind  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  1.2.2.2  rmind  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  1.2.2.2  rmind  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  1.2.2.2  rmind  * SUCH DAMAGE.
     30  1.2.2.2  rmind  */
     31  1.2.2.2  rmind 
     32  1.2.2.2  rmind /*-
     33  1.2.2.2  rmind  * Copyright (c) 2010 The NetBSD Foundation, Inc.
     34  1.2.2.2  rmind  * All rights reserved.
     35  1.2.2.2  rmind  *
     36  1.2.2.2  rmind  * This code is derived from software contributed to The NetBSD Foundation
     37  1.2.2.2  rmind  * by Public Access Networks Corporation ("Panix").  It was developed under
     38  1.2.2.2  rmind  * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
     39  1.2.2.2  rmind  *
     40  1.2.2.2  rmind  * This code is derived from software contributed to The NetBSD Foundation
     41  1.2.2.2  rmind  * by Jason R. Thorpe of Zembu Labs, Inc.
     42  1.2.2.2  rmind  *
     43  1.2.2.2  rmind  * This code is derived from software contributed to The NetBSD Foundation
     44  1.2.2.2  rmind  * by Mihai Chelaru <kefren (at) NetBSD.org>
     45  1.2.2.2  rmind  *
     46  1.2.2.2  rmind  * Redistribution and use in source and binary forms, with or without
     47  1.2.2.2  rmind  * modification, are permitted provided that the following conditions
     48  1.2.2.2  rmind  * are met:
     49  1.2.2.2  rmind  * 1. Redistributions of source code must retain the above copyright
     50  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer.
     51  1.2.2.2  rmind  * 2. Redistributions in binary form must reproduce the above copyright
     52  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer in the
     53  1.2.2.2  rmind  *    documentation and/or other materials provided with the distribution.
     54  1.2.2.2  rmind  *
     55  1.2.2.2  rmind  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     56  1.2.2.2  rmind  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     57  1.2.2.2  rmind  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     58  1.2.2.2  rmind  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     59  1.2.2.2  rmind  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     60  1.2.2.2  rmind  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     61  1.2.2.2  rmind  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     62  1.2.2.2  rmind  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     63  1.2.2.2  rmind  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     64  1.2.2.2  rmind  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     65  1.2.2.2  rmind  * POSSIBILITY OF SUCH DAMAGE.
     66  1.2.2.2  rmind  */
     67  1.2.2.2  rmind 
     68  1.2.2.2  rmind /*
     69  1.2.2.2  rmind  * Copyright (c) 1982, 1986, 1988, 1993
     70  1.2.2.2  rmind  *      The Regents of the University of California.  All rights reserved.
     71  1.2.2.2  rmind  *
     72  1.2.2.2  rmind  * Redistribution and use in source and binary forms, with or without
     73  1.2.2.2  rmind  * modification, are permitted provided that the following conditions
     74  1.2.2.2  rmind  * are met:
     75  1.2.2.2  rmind  * 1. Redistributions of source code must retain the above copyright
     76  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer.
     77  1.2.2.2  rmind  * 2. Redistributions in binary form must reproduce the above copyright
     78  1.2.2.2  rmind  *    notice, this list of conditions and the following disclaimer in the
     79  1.2.2.2  rmind  *    documentation and/or other materials provided with the distribution.
     80  1.2.2.2  rmind  * 3. Neither the name of the University nor the names of its contributors
     81  1.2.2.2  rmind  *    may be used to endorse or promote products derived from this software
     82  1.2.2.2  rmind  *    without specific prior written permission.
     83  1.2.2.2  rmind  *
     84  1.2.2.2  rmind  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     85  1.2.2.2  rmind  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     86  1.2.2.2  rmind  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     87  1.2.2.2  rmind  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     88  1.2.2.2  rmind  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     89  1.2.2.2  rmind  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     90  1.2.2.2  rmind  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     91  1.2.2.2  rmind  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     92  1.2.2.2  rmind  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     93  1.2.2.2  rmind  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     94  1.2.2.2  rmind  * SUCH DAMAGE.
     95  1.2.2.2  rmind  *
     96  1.2.2.2  rmind  *      @(#)ip_icmp.c   8.2 (Berkeley) 1/4/94
     97  1.2.2.2  rmind  */
     98  1.2.2.2  rmind 
     99  1.2.2.2  rmind #include <sys/cdefs.h>
    100  1.2.2.2  rmind __KERNEL_RCSID(0, "$NetBSD: mpls_ttl.c,v 1.2.2.2 2010/07/03 01:20:00 rmind Exp $");
    101  1.2.2.2  rmind 
    102  1.2.2.2  rmind #include "opt_inet.h"
    103  1.2.2.2  rmind #include "opt_mpls.h"
    104  1.2.2.2  rmind 
    105  1.2.2.2  rmind #include <sys/param.h>
    106  1.2.2.2  rmind #include <sys/malloc.h>
    107  1.2.2.2  rmind #include <sys/mbuf.h>
    108  1.2.2.2  rmind #include <sys/errno.h>
    109  1.2.2.2  rmind #include <sys/socket.h>
    110  1.2.2.2  rmind #include <sys/systm.h>
    111  1.2.2.2  rmind 
    112  1.2.2.2  rmind #include <net/if.h>
    113  1.2.2.2  rmind #include <net/if_dl.h>
    114  1.2.2.2  rmind #include <net/route.h>
    115  1.2.2.2  rmind 
    116  1.2.2.2  rmind #include <netinet/in.h>
    117  1.2.2.2  rmind #include <netinet/in_systm.h>
    118  1.2.2.2  rmind #include <netinet/ip.h>
    119  1.2.2.2  rmind #include <netinet/ip_icmp.h>
    120  1.2.2.2  rmind #include <netinet/icmp_private.h>
    121  1.2.2.2  rmind #include <netinet/icmp_var.h>
    122  1.2.2.2  rmind 
    123  1.2.2.2  rmind #include <netmpls/mpls.h>
    124  1.2.2.2  rmind #include <netmpls/mpls_var.h>
    125  1.2.2.2  rmind 
    126  1.2.2.2  rmind #ifdef INET
    127  1.2.2.2  rmind 
    128  1.2.2.2  rmind /* in netinet/ip_icmp.c */
    129  1.2.2.2  rmind extern int icmpreturndatabytes;
    130  1.2.2.2  rmind 
    131  1.2.2.2  rmind /* ICMP Extensions */
    132  1.2.2.2  rmind 
    133  1.2.2.2  rmind #define ICMP_EXT_VERSION 2
    134  1.2.2.2  rmind #define	MPLS_RETURN_DATA 128
    135  1.2.2.2  rmind #define	ICMP_EXT_OFFSET	128
    136  1.2.2.2  rmind 
    137  1.2.2.2  rmind struct icmp_ext_cmn_hdr {
    138  1.2.2.2  rmind #if BYTE_ORDER == BIG_ENDIAN
    139  1.2.2.2  rmind         unsigned char   version:4;
    140  1.2.2.2  rmind         unsigned char   reserved1:4;
    141  1.2.2.2  rmind #else
    142  1.2.2.2  rmind         unsigned char   reserved1:4;
    143  1.2.2.2  rmind         unsigned char   version:4;
    144  1.2.2.2  rmind #endif
    145  1.2.2.2  rmind 	unsigned char   reserved2;
    146  1.2.2.2  rmind 	unsigned short  checksum;
    147  1.2.2.2  rmind };
    148  1.2.2.2  rmind 
    149  1.2.2.2  rmind struct icmp_ext_obj_hdr {
    150  1.2.2.2  rmind 	u_short length;
    151  1.2.2.2  rmind 	u_char  class_num;
    152  1.2.2.2  rmind #define MPLS_STACK_ENTRY_CLASS 1
    153  1.2.2.2  rmind 	u_char  c_type;
    154  1.2.2.2  rmind #define MPLS_STACK_ENTRY_C_TYPE 1
    155  1.2.2.2  rmind };
    156  1.2.2.2  rmind 
    157  1.2.2.2  rmind struct mpls_extension {
    158  1.2.2.2  rmind 	struct icmp_ext_cmn_hdr cmn_hdr;
    159  1.2.2.2  rmind 	struct icmp_ext_obj_hdr obj_hdr;
    160  1.2.2.2  rmind 	union mpls_shim ms;
    161  1.2.2.2  rmind } __packed;
    162  1.2.2.2  rmind 
    163  1.2.2.2  rmind static void mpls_icmp_error(struct mbuf*, int, int, n_long, int, union mpls_shim *);
    164  1.2.2.2  rmind 
    165  1.2.2.2  rmind /*
    166  1.2.2.2  rmind  * http://www.ietf.org/proceedings/01aug/I-D/draft-ietf-mpls-icmp-02.txt
    167  1.2.2.2  rmind  * This should be in sync with icmp_error() in sys/netinet/ip_icmp.c
    168  1.2.2.2  rmind  */
    169  1.2.2.2  rmind 
    170  1.2.2.2  rmind static void
    171  1.2.2.2  rmind mpls_icmp_error(struct mbuf *n, int type, int code, n_long dest,
    172  1.2.2.2  rmind     int destmtu, union mpls_shim *shim)
    173  1.2.2.2  rmind {
    174  1.2.2.2  rmind 	struct ip *oip = mtod(n, struct ip *), *nip;
    175  1.2.2.2  rmind 	unsigned oiplen = oip->ip_hl << 2;
    176  1.2.2.2  rmind 	struct icmp *icp;
    177  1.2.2.2  rmind 	struct mbuf *m;
    178  1.2.2.2  rmind 	unsigned icmplen, mblen, packetlen;
    179  1.2.2.2  rmind 	struct mpls_extension mpls_icmp_ext;
    180  1.2.2.2  rmind 
    181  1.2.2.2  rmind 	memset(&mpls_icmp_ext, 0, sizeof(mpls_icmp_ext));
    182  1.2.2.2  rmind 	mpls_icmp_ext.cmn_hdr.version = ICMP_EXT_VERSION;
    183  1.2.2.2  rmind 	mpls_icmp_ext.cmn_hdr.checksum = 0;
    184  1.2.2.2  rmind 
    185  1.2.2.2  rmind 	mpls_icmp_ext.obj_hdr.length = htons(sizeof(union mpls_shim) +
    186  1.2.2.2  rmind 					sizeof(struct icmp_ext_obj_hdr));
    187  1.2.2.2  rmind 	mpls_icmp_ext.obj_hdr.class_num = MPLS_STACK_ENTRY_CLASS;
    188  1.2.2.2  rmind 	mpls_icmp_ext.obj_hdr.c_type = MPLS_STACK_ENTRY_C_TYPE;
    189  1.2.2.2  rmind 
    190  1.2.2.2  rmind 	mpls_icmp_ext.ms.s_addr = shim->s_addr;
    191  1.2.2.2  rmind 
    192  1.2.2.2  rmind #ifdef ICMPPRINTFS
    193  1.2.2.2  rmind 	if (icmpprintfs)
    194  1.2.2.2  rmind 		printf("mpls_icmp_error(%p, type:%d, code:%d)\n", oip, type,
    195  1.2.2.2  rmind 			code);
    196  1.2.2.2  rmind #endif
    197  1.2.2.2  rmind 	if (type != ICMP_REDIRECT)
    198  1.2.2.2  rmind 		ICMP_STATINC(ICMP_STAT_ERROR);
    199  1.2.2.2  rmind 	/*
    200  1.2.2.2  rmind 	 * Don't send error if the original packet was encrypted.
    201  1.2.2.2  rmind 	 * Don't send error if not the first fragment of message.
    202  1.2.2.2  rmind 	 * Don't error if the old packet protocol was ICMP
    203  1.2.2.2  rmind 	 * error message, only known informational types.
    204  1.2.2.2  rmind 	 */
    205  1.2.2.2  rmind 	if (n->m_flags & M_DECRYPTED)
    206  1.2.2.2  rmind 		goto freeit;
    207  1.2.2.2  rmind 	if (oip->ip_off &~ htons(IP_MF|IP_DF))
    208  1.2.2.2  rmind 		goto freeit;
    209  1.2.2.2  rmind 	if (oip->ip_p == IPPROTO_ICMP && type != ICMP_REDIRECT &&
    210  1.2.2.2  rmind 	    n->m_len >= oiplen + ICMP_MINLEN &&
    211  1.2.2.2  rmind 	    !ICMP_INFOTYPE(((struct icmp *)((char *)oip + oiplen))->icmp_type))
    212  1.2.2.2  rmind 	{
    213  1.2.2.2  rmind 		ICMP_STATINC(ICMP_STAT_OLDICMP);
    214  1.2.2.2  rmind 		goto freeit;
    215  1.2.2.2  rmind 	}
    216  1.2.2.2  rmind 	/* Don't send error in response to a multicast or broadcast packet */
    217  1.2.2.2  rmind 	if (n->m_flags & (M_BCAST|M_MCAST))
    218  1.2.2.2  rmind 		goto freeit;
    219  1.2.2.2  rmind 
    220  1.2.2.2  rmind 	/*
    221  1.2.2.2  rmind 	 * First, do a rate limitation check.
    222  1.2.2.2  rmind 	 */
    223  1.2.2.2  rmind 	if (icmp_ratelimit(&oip->ip_src, type, code))
    224  1.2.2.2  rmind 		/* XXX stats */
    225  1.2.2.2  rmind 		goto freeit;
    226  1.2.2.2  rmind 
    227  1.2.2.2  rmind 	/*
    228  1.2.2.2  rmind 	 * Now, formulate icmp message
    229  1.2.2.2  rmind 	 */
    230  1.2.2.2  rmind 	icmplen = min(ICMP_EXT_OFFSET, ntohs(oip->ip_len));
    231  1.2.2.2  rmind 	/*
    232  1.2.2.2  rmind 	 * Defend against mbuf chains shorter than oip->ip_len - oiplen:
    233  1.2.2.2  rmind 	 */
    234  1.2.2.2  rmind 	mblen = 0;
    235  1.2.2.2  rmind 	for (m = n; m && (mblen < icmplen); m = m->m_next)
    236  1.2.2.2  rmind 		mblen += m->m_len;
    237  1.2.2.2  rmind 	icmplen = min(mblen, icmplen);
    238  1.2.2.2  rmind 
    239  1.2.2.2  rmind 	packetlen = sizeof(struct ip) + ICMP_EXT_OFFSET + sizeof(mpls_icmp_ext);
    240  1.2.2.2  rmind 
    241  1.2.2.2  rmind 	/*
    242  1.2.2.2  rmind 	 * As we are not required to return everything we have,
    243  1.2.2.2  rmind 	 * we return whatever we can return at ease.
    244  1.2.2.2  rmind 	 *
    245  1.2.2.2  rmind 	 * Note that ICMP datagrams longer than 576 octets are out of spec
    246  1.2.2.2  rmind 	 * according to RFC1812; the limit on icmpreturndatabytes below in
    247  1.2.2.2  rmind 	 * icmp_sysctl will keep things below that limit.
    248  1.2.2.2  rmind 	 */
    249  1.2.2.2  rmind 
    250  1.2.2.2  rmind 	KASSERT (packetlen <= MCLBYTES);
    251  1.2.2.2  rmind 
    252  1.2.2.2  rmind 	m = m_gethdr(M_DONTWAIT, MT_HEADER);
    253  1.2.2.2  rmind 	if (m && (packetlen > MHLEN)) {
    254  1.2.2.2  rmind 		MCLGET(m, M_DONTWAIT);
    255  1.2.2.2  rmind 		if ((m->m_flags & M_EXT) == 0) {
    256  1.2.2.2  rmind 			m_freem(m);
    257  1.2.2.2  rmind 			m = NULL;
    258  1.2.2.2  rmind 		}
    259  1.2.2.2  rmind 	}
    260  1.2.2.2  rmind 	if (m == NULL)
    261  1.2.2.2  rmind 		goto freeit;
    262  1.2.2.2  rmind 	MCLAIM(m, n->m_owner);
    263  1.2.2.2  rmind 	m->m_len = packetlen;
    264  1.2.2.2  rmind 	if ((m->m_flags & M_EXT) == 0)
    265  1.2.2.2  rmind 		MH_ALIGN(m, m->m_len);
    266  1.2.2.2  rmind 	else {
    267  1.2.2.2  rmind 		m->m_data += sizeof(struct ip);
    268  1.2.2.2  rmind 		m->m_len -= sizeof(struct ip);
    269  1.2.2.2  rmind 	}
    270  1.2.2.2  rmind 	icp = mtod(m, struct icmp *);
    271  1.2.2.2  rmind 	if ((u_int)type > ICMP_MAXTYPE)
    272  1.2.2.2  rmind 		panic("icmp error");
    273  1.2.2.2  rmind 	ICMP_STATINC(ICMP_STAT_OUTHIST + type);
    274  1.2.2.2  rmind 	icp->icmp_type = type;
    275  1.2.2.2  rmind 	if (type == ICMP_REDIRECT)
    276  1.2.2.2  rmind 		icp->icmp_gwaddr.s_addr = dest;
    277  1.2.2.2  rmind 	else {
    278  1.2.2.2  rmind 		icp->icmp_void = 0;
    279  1.2.2.2  rmind 		/*
    280  1.2.2.2  rmind 		 * The following assignments assume an overlay with the
    281  1.2.2.2  rmind 		 * zeroed icmp_void field.
    282  1.2.2.2  rmind 		 */
    283  1.2.2.2  rmind 		if (type == ICMP_PARAMPROB) {
    284  1.2.2.2  rmind 			icp->icmp_pptr = code;
    285  1.2.2.2  rmind 			code = 0;
    286  1.2.2.2  rmind 		} else if (type == ICMP_UNREACH &&
    287  1.2.2.2  rmind 		    code == ICMP_UNREACH_NEEDFRAG && destmtu)
    288  1.2.2.2  rmind 			icp->icmp_nextmtu = htons(destmtu);
    289  1.2.2.2  rmind 	}
    290  1.2.2.2  rmind 
    291  1.2.2.2  rmind 	icp->icmp_code = code;
    292  1.2.2.2  rmind 
    293  1.2.2.2  rmind 	memset(&icp->icmp_ip, 0, ICMP_EXT_OFFSET);
    294  1.2.2.2  rmind 	m_copydata(n, 0, icmplen, (char *)&icp->icmp_ip);
    295  1.2.2.2  rmind 
    296  1.2.2.2  rmind 	/* Append the extension structure */
    297  1.2.2.2  rmind 	memcpy(((char*)&icp->icmp_ip) + ICMP_EXT_OFFSET,
    298  1.2.2.2  rmind 	    &mpls_icmp_ext, sizeof(mpls_icmp_ext));
    299  1.2.2.2  rmind 
    300  1.2.2.2  rmind 	/*
    301  1.2.2.2  rmind 	 * Now, copy old ip header (without options)
    302  1.2.2.2  rmind 	 * in front of icmp message.
    303  1.2.2.2  rmind 	*/
    304  1.2.2.2  rmind 	if ((m->m_flags & M_EXT) == 0 &&
    305  1.2.2.2  rmind 	    m->m_data - sizeof(struct ip) < m->m_pktdat)
    306  1.2.2.2  rmind 		panic("icmp len");
    307  1.2.2.2  rmind 	m->m_data -= sizeof(struct ip);
    308  1.2.2.2  rmind 	m->m_len += sizeof(struct ip);
    309  1.2.2.2  rmind 	m->m_pkthdr.len = m->m_len;
    310  1.2.2.2  rmind 	m->m_pkthdr.rcvif = n->m_pkthdr.rcvif;
    311  1.2.2.2  rmind 	nip = mtod(m, struct ip *);
    312  1.2.2.2  rmind 	/* ip_v set in ip_output */
    313  1.2.2.2  rmind 	nip->ip_hl = sizeof(struct ip) >> 2;
    314  1.2.2.2  rmind 	nip->ip_tos = 0;
    315  1.2.2.2  rmind 	nip->ip_len = htons(m->m_len);
    316  1.2.2.2  rmind 	/* ip_id set in ip_output */
    317  1.2.2.2  rmind 	nip->ip_off = htons(0);
    318  1.2.2.2  rmind 	/* ip_ttl set in icmp_reflect */
    319  1.2.2.2  rmind 	nip->ip_p = IPPROTO_ICMP;
    320  1.2.2.2  rmind 	nip->ip_src = oip->ip_src;
    321  1.2.2.2  rmind 	nip->ip_dst = oip->ip_dst;
    322  1.2.2.2  rmind 	icmp_reflect(m);
    323  1.2.2.2  rmind 
    324  1.2.2.2  rmind freeit:
    325  1.2.2.2  rmind 	m_freem(n);
    326  1.2.2.2  rmind 
    327  1.2.2.2  rmind }
    328  1.2.2.2  rmind 
    329  1.2.2.2  rmind #endif	/* INET */
    330  1.2.2.2  rmind 
    331  1.2.2.2  rmind struct mbuf *
    332  1.2.2.2  rmind mpls_ttl_dec(struct mbuf *m)
    333  1.2.2.2  rmind {
    334  1.2.2.2  rmind 	union mpls_shim *mshim;
    335  1.2.2.2  rmind #ifdef INET
    336  1.2.2.2  rmind 	union mpls_shim top_shim, bossh;
    337  1.2.2.2  rmind #endif
    338  1.2.2.2  rmind 
    339  1.2.2.2  rmind 	if (m->m_len < sizeof(union mpls_shim) &&
    340  1.2.2.2  rmind 	    (m = m_pullup(m, sizeof(union mpls_shim))) == NULL)
    341  1.2.2.2  rmind 		return NULL;
    342  1.2.2.2  rmind 	mshim = mtod(m, union mpls_shim *);
    343  1.2.2.2  rmind 	mshim->s_addr = ntohl(mshim->s_addr);
    344  1.2.2.2  rmind 	mshim->shim.ttl--;
    345  1.2.2.2  rmind 
    346  1.2.2.2  rmind 	if (mshim->shim.ttl == 0) {
    347  1.2.2.2  rmind 		if (!mpls_icmp_respond) {
    348  1.2.2.2  rmind 			m_freem(m);
    349  1.2.2.2  rmind 			return NULL;
    350  1.2.2.2  rmind 		}
    351  1.2.2.2  rmind 
    352  1.2.2.2  rmind #ifdef INET
    353  1.2.2.2  rmind 		/*
    354  1.2.2.2  rmind 		 * shim ttl exceeded
    355  1.2.2.2  rmind 		 * send back ICMP type 11 code 0
    356  1.2.2.2  rmind 		 */
    357  1.2.2.2  rmind 		bossh.s_addr = mshim->s_addr;
    358  1.2.2.2  rmind 		top_shim.s_addr = htonl(mshim->s_addr);
    359  1.2.2.2  rmind 		m_adj(m, sizeof(union mpls_shim));
    360  1.2.2.2  rmind 
    361  1.2.2.2  rmind 		/* Goto BOS */
    362  1.2.2.2  rmind 		while(bossh.shim.bos == 0) {
    363  1.2.2.2  rmind 			if (m->m_len < sizeof(union mpls_shim) &&
    364  1.2.2.2  rmind 			    (m = m_pullup(m, sizeof(union mpls_shim))) == NULL) {
    365  1.2.2.2  rmind 				m_freem(m);
    366  1.2.2.2  rmind 				return NULL;
    367  1.2.2.2  rmind 			}
    368  1.2.2.2  rmind 			bossh.s_addr = ntohl(mtod(m, union mpls_shim *)->s_addr);
    369  1.2.2.2  rmind 			m_adj(m, sizeof(union mpls_shim));
    370  1.2.2.2  rmind 		}
    371  1.2.2.2  rmind 
    372  1.2.2.2  rmind 		mpls_icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS,
    373  1.2.2.2  rmind 		    0, 0, &top_shim);
    374  1.2.2.2  rmind #else
    375  1.2.2.2  rmind 		m_freem(m);
    376  1.2.2.2  rmind #endif
    377  1.2.2.2  rmind 		return NULL;
    378  1.2.2.2  rmind 	}
    379  1.2.2.2  rmind 
    380  1.2.2.2  rmind 	mshim->s_addr = htonl(mshim->s_addr);
    381  1.2.2.2  rmind 
    382  1.2.2.2  rmind 	return m;
    383  1.2.2.2  rmind }
    384