Home | History | Annotate | Line # | Download | only in netinet
ip_input.c revision 1.345
      1 /*	$NetBSD: ip_input.c,v 1.345 2016/12/08 05:16:33 ozaki-r Exp $	*/
      2 
      3 /*
      4  * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the project nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 /*-
     33  * Copyright (c) 1998 The NetBSD Foundation, Inc.
     34  * All rights reserved.
     35  *
     36  * This code is derived from software contributed to The NetBSD Foundation
     37  * by Public Access Networks Corporation ("Panix").  It was developed under
     38  * contract to Panix by Eric Haszlakiewicz and Thor Lancelot Simon.
     39  *
     40  * Redistribution and use in source and binary forms, with or without
     41  * modification, are permitted provided that the following conditions
     42  * are met:
     43  * 1. Redistributions of source code must retain the above copyright
     44  *    notice, this list of conditions and the following disclaimer.
     45  * 2. Redistributions in binary form must reproduce the above copyright
     46  *    notice, this list of conditions and the following disclaimer in the
     47  *    documentation and/or other materials provided with the distribution.
     48  *
     49  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     50  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     51  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     52  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     53  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     54  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     55  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     56  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     57  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     58  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     59  * POSSIBILITY OF SUCH DAMAGE.
     60  */
     61 
     62 /*
     63  * Copyright (c) 1982, 1986, 1988, 1993
     64  *	The Regents of the University of California.  All rights reserved.
     65  *
     66  * Redistribution and use in source and binary forms, with or without
     67  * modification, are permitted provided that the following conditions
     68  * are met:
     69  * 1. Redistributions of source code must retain the above copyright
     70  *    notice, this list of conditions and the following disclaimer.
     71  * 2. Redistributions in binary form must reproduce the above copyright
     72  *    notice, this list of conditions and the following disclaimer in the
     73  *    documentation and/or other materials provided with the distribution.
     74  * 3. Neither the name of the University nor the names of its contributors
     75  *    may be used to endorse or promote products derived from this software
     76  *    without specific prior written permission.
     77  *
     78  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     79  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     80  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     81  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     82  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     83  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     84  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     85  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     86  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     87  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     88  * SUCH DAMAGE.
     89  *
     90  *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
     91  */
     92 
     93 #include <sys/cdefs.h>
     94 __KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.345 2016/12/08 05:16:33 ozaki-r Exp $");
     95 
     96 #ifdef _KERNEL_OPT
     97 #include "opt_inet.h"
     98 #include "opt_compat_netbsd.h"
     99 #include "opt_gateway.h"
    100 #include "opt_ipsec.h"
    101 #include "opt_mrouting.h"
    102 #include "opt_mbuftrace.h"
    103 #include "opt_inet_csum.h"
    104 #include "opt_net_mpsafe.h"
    105 #endif
    106 
    107 #include "arp.h"
    108 
    109 #include <sys/param.h>
    110 #include <sys/systm.h>
    111 #include <sys/cpu.h>
    112 #include <sys/mbuf.h>
    113 #include <sys/domain.h>
    114 #include <sys/protosw.h>
    115 #include <sys/socket.h>
    116 #include <sys/socketvar.h>
    117 #include <sys/errno.h>
    118 #include <sys/time.h>
    119 #include <sys/kernel.h>
    120 #include <sys/pool.h>
    121 #include <sys/sysctl.h>
    122 #include <sys/kauth.h>
    123 
    124 #include <net/if.h>
    125 #include <net/if_dl.h>
    126 #include <net/route.h>
    127 #include <net/pktqueue.h>
    128 #include <net/pfil.h>
    129 
    130 #include <netinet/in.h>
    131 #include <netinet/in_systm.h>
    132 #include <netinet/ip.h>
    133 #include <netinet/in_pcb.h>
    134 #include <netinet/in_proto.h>
    135 #include <netinet/in_var.h>
    136 #include <netinet/ip_var.h>
    137 #include <netinet/ip_private.h>
    138 #include <netinet/ip_icmp.h>
    139 /* just for gif_ttl */
    140 #include <netinet/in_gif.h>
    141 #include "gif.h"
    142 #include <net/if_gre.h>
    143 #include "gre.h"
    144 
    145 #ifdef MROUTING
    146 #include <netinet/ip_mroute.h>
    147 #endif
    148 #include <netinet/portalgo.h>
    149 
    150 #ifdef IPSEC
    151 #include <netipsec/ipsec.h>
    152 #endif
    153 
    154 #ifndef	IPFORWARDING
    155 #ifdef GATEWAY
    156 #define	IPFORWARDING	1	/* forward IP packets not for us */
    157 #else /* GATEWAY */
    158 #define	IPFORWARDING	0	/* don't forward IP packets not for us */
    159 #endif /* GATEWAY */
    160 #endif /* IPFORWARDING */
    161 #ifndef	IPSENDREDIRECTS
    162 #define	IPSENDREDIRECTS	1
    163 #endif
    164 #ifndef IPFORWSRCRT
    165 #define	IPFORWSRCRT	1	/* forward source-routed packets */
    166 #endif
    167 #ifndef IPALLOWSRCRT
    168 #define	IPALLOWSRCRT	1	/* allow source-routed packets */
    169 #endif
    170 #ifndef IPMTUDISC
    171 #define IPMTUDISC	1
    172 #endif
    173 #ifndef IPMTUDISCTIMEOUT
    174 #define IPMTUDISCTIMEOUT (10 * 60)	/* as per RFC 1191 */
    175 #endif
    176 
    177 #ifdef COMPAT_50
    178 #include <compat/sys/time.h>
    179 #include <compat/sys/socket.h>
    180 #endif
    181 
    182 /*
    183  * Note: DIRECTED_BROADCAST is handled this way so that previous
    184  * configuration using this option will Just Work.
    185  */
    186 #ifndef IPDIRECTEDBCAST
    187 #ifdef DIRECTED_BROADCAST
    188 #define IPDIRECTEDBCAST	1
    189 #else
    190 #define	IPDIRECTEDBCAST	0
    191 #endif /* DIRECTED_BROADCAST */
    192 #endif /* IPDIRECTEDBCAST */
    193 int	ipforwarding = IPFORWARDING;
    194 int	ipsendredirects = IPSENDREDIRECTS;
    195 int	ip_defttl = IPDEFTTL;
    196 int	ip_forwsrcrt = IPFORWSRCRT;
    197 int	ip_directedbcast = IPDIRECTEDBCAST;
    198 int	ip_allowsrcrt = IPALLOWSRCRT;
    199 int	ip_mtudisc = IPMTUDISC;
    200 int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
    201 #ifdef DIAGNOSTIC
    202 int	ipprintfs = 0;
    203 #endif
    204 
    205 int	ip_do_randomid = 0;
    206 
    207 /*
    208  * XXX - Setting ip_checkinterface mostly implements the receive side of
    209  * the Strong ES model described in RFC 1122, but since the routing table
    210  * and transmit implementation do not implement the Strong ES model,
    211  * setting this to 1 results in an odd hybrid.
    212  *
    213  * XXX - ip_checkinterface currently must be disabled if you use ipnat
    214  * to translate the destination address to another local interface.
    215  *
    216  * XXX - ip_checkinterface must be disabled if you add IP aliases
    217  * to the loopback interface instead of the interface where the
    218  * packets for those addresses are received.
    219  */
    220 static int		ip_checkinterface	__read_mostly = 0;
    221 
    222 struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
    223 
    224 pktqueue_t *		ip_pktq			__read_mostly;
    225 pfil_head_t *		inet_pfil_hook		__read_mostly;
    226 ipid_state_t *		ip_ids			__read_mostly;
    227 percpu_t *		ipstat_percpu		__read_mostly;
    228 
    229 static percpu_t		*ipforward_rt_percpu	__cacheline_aligned;
    230 
    231 uint16_t ip_id;
    232 
    233 #ifdef INET_CSUM_COUNTERS
    234 #include <sys/device.h>
    235 
    236 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    237     NULL, "inet", "hwcsum bad");
    238 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    239     NULL, "inet", "hwcsum ok");
    240 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    241     NULL, "inet", "swcsum");
    242 
    243 #define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
    244 
    245 EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
    246 EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
    247 EVCNT_ATTACH_STATIC(ip_swcsum);
    248 
    249 #else
    250 
    251 #define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
    252 
    253 #endif /* INET_CSUM_COUNTERS */
    254 
    255 /*
    256  * We need to save the IP options in case a protocol wants to respond
    257  * to an incoming packet over the same route if the packet got here
    258  * using IP source routing.  This allows connection establishment and
    259  * maintenance when the remote end is on a network that is not known
    260  * to us.
    261  */
    262 
    263 static int	ip_nhops = 0;
    264 
    265 static	struct ip_srcrt {
    266 	struct	in_addr dst;			/* final destination */
    267 	char	nop;				/* one NOP to align */
    268 	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
    269 	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
    270 } ip_srcrt;
    271 
    272 static int ip_drainwanted;
    273 
    274 struct	sockaddr_in ipaddr = {
    275 	.sin_len = sizeof(ipaddr),
    276 	.sin_family = AF_INET,
    277 };
    278 
    279 static void save_rte(u_char *, struct in_addr);
    280 
    281 #ifdef MBUFTRACE
    282 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
    283 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
    284 #endif
    285 
    286 static void		ipintr(void *);
    287 static void		ip_input(struct mbuf *);
    288 static void		ip_forward(struct mbuf *, int, struct ifnet *);
    289 static bool		ip_dooptions(struct mbuf *);
    290 static struct in_ifaddr *ip_rtaddr(struct in_addr);
    291 static void		sysctl_net_inet_ip_setup(struct sysctllog **);
    292 
    293 static struct in_ifaddr	*ip_match_our_address(struct ifnet *, struct ip *,
    294 			    int *);
    295 static struct in_ifaddr	*ip_match_our_address_broadcast(struct ifnet *,
    296 			    struct ip *);
    297 
    298 #ifdef NET_MPSAFE
    299 #define	SOFTNET_LOCK()		mutex_enter(softnet_lock)
    300 #define	SOFTNET_UNLOCK()	mutex_exit(softnet_lock)
    301 #else
    302 #define	SOFTNET_LOCK()		KASSERT(mutex_owned(softnet_lock))
    303 #define	SOFTNET_UNLOCK()	KASSERT(mutex_owned(softnet_lock))
    304 #endif
    305 
    306 /*
    307  * IP initialization: fill in IP protocol switch table.
    308  * All protocols not implemented in kernel go to raw IP protocol handler.
    309  */
    310 void
    311 ip_init(void)
    312 {
    313 	const struct protosw *pr;
    314 
    315 	in_init();
    316 	sysctl_net_inet_ip_setup(NULL);
    317 
    318 	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
    319 	KASSERT(pr != NULL);
    320 
    321 	ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL);
    322 	KASSERT(ip_pktq != NULL);
    323 
    324 	for (u_int i = 0; i < IPPROTO_MAX; i++) {
    325 		ip_protox[i] = pr - inetsw;
    326 	}
    327 	for (pr = inetdomain.dom_protosw;
    328 	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
    329 		if (pr->pr_domain->dom_family == PF_INET &&
    330 		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
    331 			ip_protox[pr->pr_protocol] = pr - inetsw;
    332 
    333 	ip_reass_init();
    334 
    335 	ip_ids = ip_id_init();
    336 	ip_id = time_uptime & 0xfffff;
    337 
    338 	ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout);
    339 #ifdef GATEWAY
    340 	ipflow_init();
    341 #endif
    342 
    343 	/* Register our Packet Filter hook. */
    344 	inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET);
    345 	KASSERT(inet_pfil_hook != NULL);
    346 
    347 #ifdef MBUFTRACE
    348 	MOWNER_ATTACH(&ip_tx_mowner);
    349 	MOWNER_ATTACH(&ip_rx_mowner);
    350 #endif /* MBUFTRACE */
    351 
    352 	ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
    353 
    354 	ipforward_rt_percpu = percpu_alloc(sizeof(struct route));
    355 	if (ipforward_rt_percpu == NULL)
    356 		panic("failed to allocate ipforward_rt_percpu");
    357 }
    358 
    359 static struct in_ifaddr *
    360 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch)
    361 {
    362 	struct in_ifaddr *ia = NULL;
    363 	int checkif;
    364 
    365 	/*
    366 	 * Enable a consistency check between the destination address
    367 	 * and the arrival interface for a unicast packet (the RFC 1122
    368 	 * strong ES model) if IP forwarding is disabled and the packet
    369 	 * is not locally generated.
    370 	 *
    371 	 * XXX - Checking also should be disabled if the destination
    372 	 * address is ipnat'ed to a different interface.
    373 	 *
    374 	 * XXX - Checking is incompatible with IP aliases added
    375 	 * to the loopback interface instead of the interface where
    376 	 * the packets are received.
    377 	 *
    378 	 * XXX - We need to add a per ifaddr flag for this so that
    379 	 * we get finer grain control.
    380 	 */
    381 	checkif = ip_checkinterface && (ipforwarding == 0) &&
    382 	    (ifp->if_flags & IFF_LOOPBACK) == 0;
    383 
    384 	IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) {
    385 		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
    386 			if (ia->ia4_flags & IN_IFF_NOTREADY)
    387 				continue;
    388 			if (checkif && ia->ia_ifp != ifp)
    389 				continue;
    390 			if ((ia->ia_ifp->if_flags & IFF_UP) != 0 &&
    391 			    (ia->ia4_flags & IN_IFF_DETACHED) == 0)
    392 				break;
    393 			else
    394 				(*downmatch)++;
    395 		}
    396 	}
    397 
    398 	return ia;
    399 }
    400 
    401 static struct in_ifaddr *
    402 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip)
    403 {
    404 	struct in_ifaddr *ia = NULL;
    405 	struct ifaddr *ifa;
    406 
    407 	IFADDR_READER_FOREACH(ifa, ifp) {
    408 		if (ifa->ifa_addr->sa_family != AF_INET)
    409 			continue;
    410 		ia = ifatoia(ifa);
    411 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
    412 			continue;
    413 		if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
    414 		    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
    415 		    /*
    416 		     * Look for all-0's host part (old broadcast addr),
    417 		     * either for subnet or net.
    418 		     */
    419 		    ip->ip_dst.s_addr == ia->ia_subnet ||
    420 		    ip->ip_dst.s_addr == ia->ia_net)
    421 			goto matched;
    422 		/*
    423 		 * An interface with IP address zero accepts
    424 		 * all packets that arrive on that interface.
    425 		 */
    426 		if (in_nullhost(ia->ia_addr.sin_addr))
    427 			goto matched;
    428 	}
    429 	ia = NULL;
    430 
    431 matched:
    432 	return ia;
    433 }
    434 
    435 /*
    436  * IP software interrupt routine.
    437  */
    438 static void
    439 ipintr(void *arg __unused)
    440 {
    441 	struct mbuf *m;
    442 
    443 	KASSERT(cpu_softintr_p());
    444 
    445 #ifndef NET_MPSAFE
    446 	mutex_enter(softnet_lock);
    447 #endif
    448 	while ((m = pktq_dequeue(ip_pktq)) != NULL) {
    449 		ip_input(m);
    450 	}
    451 #ifndef NET_MPSAFE
    452 	mutex_exit(softnet_lock);
    453 #endif
    454 }
    455 
    456 /*
    457  * IP input routine.  Checksum and byte swap header.  If fragmented
    458  * try to reassemble.  Process options.  Pass to next level.
    459  */
    460 static void
    461 ip_input(struct mbuf *m)
    462 {
    463 	struct ip *ip = NULL;
    464 	struct in_ifaddr *ia = NULL;
    465 	int hlen = 0, len;
    466 	int downmatch;
    467 	int srcrt = 0;
    468 	ifnet_t *ifp;
    469 	struct psref psref;
    470 	int s;
    471 
    472 	KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software "
    473 	    "interrupt handler; synchronization assumptions violated");
    474 
    475 	MCLAIM(m, &ip_rx_mowner);
    476 	KASSERT((m->m_flags & M_PKTHDR) != 0);
    477 
    478 	ifp = m_get_rcvif_psref(m, &psref);
    479 	if (__predict_false(ifp == NULL))
    480 		goto out;
    481 
    482 	/*
    483 	 * If no IP addresses have been set yet but the interfaces
    484 	 * are receiving, can't do anything with incoming packets yet.
    485 	 * Note: we pre-check without locks held.
    486 	 */
    487 	if (IN_ADDRLIST_READER_EMPTY())
    488 		goto out;
    489 	IP_STATINC(IP_STAT_TOTAL);
    490 
    491 	/*
    492 	 * If the IP header is not aligned, slurp it up into a new
    493 	 * mbuf with space for link headers, in the event we forward
    494 	 * it.  Otherwise, if it is aligned, make sure the entire
    495 	 * base IP header is in the first mbuf of the chain.
    496 	 */
    497 	if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
    498 		if ((m = m_copyup(m, sizeof(struct ip),
    499 				  (max_linkhdr + 3) & ~3)) == NULL) {
    500 			/* XXXJRT new stat, please */
    501 			IP_STATINC(IP_STAT_TOOSMALL);
    502 			goto out;
    503 		}
    504 	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
    505 		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
    506 			IP_STATINC(IP_STAT_TOOSMALL);
    507 			goto out;
    508 		}
    509 	}
    510 	ip = mtod(m, struct ip *);
    511 	if (ip->ip_v != IPVERSION) {
    512 		IP_STATINC(IP_STAT_BADVERS);
    513 		goto out;
    514 	}
    515 	hlen = ip->ip_hl << 2;
    516 	if (hlen < sizeof(struct ip)) {	/* minimum header length */
    517 		IP_STATINC(IP_STAT_BADHLEN);
    518 		goto out;
    519 	}
    520 	if (hlen > m->m_len) {
    521 		if ((m = m_pullup(m, hlen)) == NULL) {
    522 			IP_STATINC(IP_STAT_BADHLEN);
    523 			goto out;
    524 		}
    525 		ip = mtod(m, struct ip *);
    526 	}
    527 
    528 	/*
    529 	 * RFC1122: packets with a multicast source address are
    530 	 * not allowed.
    531 	 */
    532 	if (IN_MULTICAST(ip->ip_src.s_addr)) {
    533 		IP_STATINC(IP_STAT_BADADDR);
    534 		goto out;
    535 	}
    536 
    537 	/* 127/8 must not appear on wire - RFC1122 */
    538 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
    539 	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
    540 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
    541 			IP_STATINC(IP_STAT_BADADDR);
    542 			goto out;
    543 		}
    544 	}
    545 
    546 	switch (m->m_pkthdr.csum_flags &
    547 		((ifp->if_csum_flags_rx & M_CSUM_IPv4) |
    548 		 M_CSUM_IPv4_BAD)) {
    549 	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
    550 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
    551 		IP_STATINC(IP_STAT_BADSUM);
    552 		goto out;
    553 
    554 	case M_CSUM_IPv4:
    555 		/* Checksum was okay. */
    556 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
    557 		break;
    558 
    559 	default:
    560 		/*
    561 		 * Must compute it ourselves.  Maybe skip checksum on
    562 		 * loopback interfaces.
    563 		 */
    564 		if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) ||
    565 		    ip_do_loopback_cksum)) {
    566 			INET_CSUM_COUNTER_INCR(&ip_swcsum);
    567 			if (in_cksum(m, hlen) != 0) {
    568 				IP_STATINC(IP_STAT_BADSUM);
    569 				goto out;
    570 			}
    571 		}
    572 		break;
    573 	}
    574 
    575 	/* Retrieve the packet length. */
    576 	len = ntohs(ip->ip_len);
    577 
    578 	/*
    579 	 * Check for additional length bogosity
    580 	 */
    581 	if (len < hlen) {
    582 		IP_STATINC(IP_STAT_BADLEN);
    583 		goto out;
    584 	}
    585 
    586 	/*
    587 	 * Check that the amount of data in the buffers
    588 	 * is as at least much as the IP header would have us expect.
    589 	 * Trim mbufs if longer than we expect.
    590 	 * Drop packet if shorter than we expect.
    591 	 */
    592 	if (m->m_pkthdr.len < len) {
    593 		IP_STATINC(IP_STAT_TOOSHORT);
    594 		goto out;
    595 	}
    596 	if (m->m_pkthdr.len > len) {
    597 		if (m->m_len == m->m_pkthdr.len) {
    598 			m->m_len = len;
    599 			m->m_pkthdr.len = len;
    600 		} else
    601 			m_adj(m, len - m->m_pkthdr.len);
    602 	}
    603 
    604 	/*
    605 	 * Assume that we can create a fast-forward IP flow entry
    606 	 * based on this packet.
    607 	 */
    608 	m->m_flags |= M_CANFASTFWD;
    609 
    610 	/*
    611 	 * Run through list of hooks for input packets.  If there are any
    612 	 * filters which require that additional packets in the flow are
    613 	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
    614 	 * Note that filters must _never_ set this flag, as another filter
    615 	 * in the list may have previously cleared it.
    616 	 */
    617 #if defined(IPSEC)
    618 	if (!ipsec_used || !ipsec_indone(m))
    619 #else
    620 	if (1)
    621 #endif
    622 	{
    623 		struct in_addr odst = ip->ip_dst;
    624 		bool freed;
    625 
    626 		freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0;
    627 		if (freed || m == NULL) {
    628 			m = NULL;
    629 			goto out;
    630 		}
    631 		ip = mtod(m, struct ip *);
    632 		hlen = ip->ip_hl << 2;
    633 
    634 		/*
    635 		 * XXX The setting of "srcrt" here is to prevent ip_forward()
    636 		 * from generating ICMP redirects for packets that have
    637 		 * been redirected by a hook back out on to the same LAN that
    638 		 * they came from and is not an indication that the packet
    639 		 * is being inffluenced by source routing options.  This
    640 		 * allows things like
    641 		 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
    642 		 * where tlp0 is both on the 1.1.1.0/24 network and is the
    643 		 * default route for hosts on 1.1.1.0/24.  Of course this
    644 		 * also requires a "map tlp0 ..." to complete the story.
    645 		 * One might argue whether or not this kind of network config.
    646 		 * should be supported in this manner...
    647 		 */
    648 		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
    649 	}
    650 
    651 #ifdef ALTQ
    652 	/* XXX Temporary until ALTQ is changed to use a pfil hook */
    653 	if (altq_input) {
    654 		SOFTNET_LOCK();
    655 		if ((*altq_input)(m, AF_INET) == 0) {
    656 			/* Packet dropped by traffic conditioner. */
    657 			SOFTNET_UNLOCK();
    658 			m = NULL;
    659 			goto out;
    660 		}
    661 		SOFTNET_UNLOCK();
    662 	}
    663 #endif
    664 
    665 	/*
    666 	 * Process options and, if not destined for us,
    667 	 * ship it on.  ip_dooptions returns 1 when an
    668 	 * error was detected (causing an icmp message
    669 	 * to be sent and the original packet to be freed).
    670 	 */
    671 	ip_nhops = 0;		/* for source routed packets */
    672 	if (hlen > sizeof (struct ip) && ip_dooptions(m)) {
    673 		m = NULL;
    674 		goto out;
    675 	}
    676 
    677 	/*
    678 	 * Check our list of addresses, to see if the packet is for us.
    679 	 *
    680 	 * Traditional 4.4BSD did not consult IFF_UP at all.
    681 	 * The behavior here is to treat addresses on !IFF_UP interface
    682 	 * or IN_IFF_NOTREADY addresses as not mine.
    683 	 */
    684 	downmatch = 0;
    685 	s = pserialize_read_enter();
    686 	ia = ip_match_our_address(ifp, ip, &downmatch);
    687 	if (ia != NULL) {
    688 		pserialize_read_exit(s);
    689 		goto ours;
    690 	}
    691 
    692 	if (ifp->if_flags & IFF_BROADCAST) {
    693 		ia = ip_match_our_address_broadcast(ifp, ip);
    694 		if (ia != NULL) {
    695 			pserialize_read_exit(s);
    696 			goto ours;
    697 		}
    698 	}
    699 	pserialize_read_exit(s);
    700 
    701 	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
    702 #ifdef MROUTING
    703 		extern struct socket *ip_mrouter;
    704 
    705 		if (ip_mrouter) {
    706 			/*
    707 			 * If we are acting as a multicast router, all
    708 			 * incoming multicast packets are passed to the
    709 			 * kernel-level multicast forwarding function.
    710 			 * The packet is returned (relatively) intact; if
    711 			 * ip_mforward() returns a non-zero value, the packet
    712 			 * must be discarded, else it may be accepted below.
    713 			 *
    714 			 * (The IP ident field is put in the same byte order
    715 			 * as expected when ip_mforward() is called from
    716 			 * ip_output().)
    717 			 */
    718 			SOFTNET_LOCK();
    719 			if (ip_mforward(m, ifp) != 0) {
    720 				SOFTNET_UNLOCK();
    721 				IP_STATINC(IP_STAT_CANTFORWARD);
    722 				goto out;
    723 			}
    724 			SOFTNET_UNLOCK();
    725 
    726 			/*
    727 			 * The process-level routing demon needs to receive
    728 			 * all multicast IGMP packets, whether or not this
    729 			 * host belongs to their destination groups.
    730 			 */
    731 			if (ip->ip_p == IPPROTO_IGMP) {
    732 				goto ours;
    733 			}
    734 			IP_STATINC(IP_STAT_CANTFORWARD);
    735 		}
    736 #endif
    737 		/*
    738 		 * See if we belong to the destination multicast group on the
    739 		 * arrival interface.
    740 		 */
    741 		if (!in_multi_group(ip->ip_dst, ifp, 0)) {
    742 			IP_STATINC(IP_STAT_CANTFORWARD);
    743 			goto out;
    744 		}
    745 		goto ours;
    746 	}
    747 	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
    748 	    in_nullhost(ip->ip_dst))
    749 		goto ours;
    750 
    751 	/*
    752 	 * Not for us; forward if possible and desirable.
    753 	 */
    754 	if (ipforwarding == 0) {
    755 		m_put_rcvif_psref(ifp, &psref);
    756 		IP_STATINC(IP_STAT_CANTFORWARD);
    757 		m_freem(m);
    758 	} else {
    759 		/*
    760 		 * If ip_dst matched any of my address on !IFF_UP interface,
    761 		 * and there's no IFF_UP interface that matches ip_dst,
    762 		 * send icmp unreach.  Forwarding it will result in in-kernel
    763 		 * forwarding loop till TTL goes to 0.
    764 		 */
    765 		if (downmatch) {
    766 			m_put_rcvif_psref(ifp, &psref);
    767 			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
    768 			IP_STATINC(IP_STAT_CANTFORWARD);
    769 			return;
    770 		}
    771 #ifdef IPSEC
    772 		/* Perform IPsec, if any. */
    773 		if (ipsec_used) {
    774 			SOFTNET_LOCK();
    775 			if (ipsec4_input(m, IP_FORWARDING |
    776 			    (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) {
    777 				SOFTNET_UNLOCK();
    778 				goto out;
    779 			}
    780 			SOFTNET_UNLOCK();
    781 		}
    782 #endif
    783 		ip_forward(m, srcrt, ifp);
    784 		m_put_rcvif_psref(ifp, &psref);
    785 	}
    786 	return;
    787 
    788 ours:
    789 	m_put_rcvif_psref(ifp, &psref);
    790 	ifp = NULL;
    791 
    792 	/*
    793 	 * If offset or IP_MF are set, must reassemble.
    794 	 */
    795 	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
    796 		/*
    797 		 * Pass to IP reassembly mechanism.
    798 		 */
    799 		if (ip_reass_packet(&m, ip) != 0) {
    800 			/* Failed; invalid fragment(s) or packet. */
    801 			goto out;
    802 		}
    803 		if (m == NULL) {
    804 			/* More fragments should come; silently return. */
    805 			goto out;
    806 		}
    807 		/*
    808 		 * Reassembly is done, we have the final packet.
    809 		 * Updated cached data in local variable(s).
    810 		 */
    811 		ip = mtod(m, struct ip *);
    812 		hlen = ip->ip_hl << 2;
    813 	}
    814 
    815 #ifdef IPSEC
    816 	/*
    817 	 * Enforce IPsec policy checking if we are seeing last header.
    818 	 * Note that we do not visit this with protocols with PCB layer
    819 	 * code - like UDP/TCP/raw IP.
    820 	 */
    821 	if (ipsec_used &&
    822 	    (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
    823 		SOFTNET_LOCK();
    824 		if (ipsec4_input(m, 0) != 0) {
    825 			SOFTNET_UNLOCK();
    826 			goto out;
    827 		}
    828 		SOFTNET_UNLOCK();
    829 	}
    830 #endif
    831 
    832 	/*
    833 	 * Switch out to protocol's input routine.
    834 	 */
    835 #if IFA_STATS
    836 	if (ia && ip) {
    837 		struct in_ifaddr *_ia;
    838 		/*
    839 		 * Keep a reference from ip_match_our_address with psref
    840 		 * is expensive, so explore ia here again.
    841 		 */
    842 		s = pserialize_read_enter();
    843 		_ia = in_get_ia(ip->ip_dst);
    844 		_ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
    845 		pserialize_read_exit(s);
    846 	}
    847 #endif
    848 	IP_STATINC(IP_STAT_DELIVERED);
    849 
    850 	const int off = hlen, nh = ip->ip_p;
    851 
    852 	SOFTNET_LOCK();
    853 	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
    854 	SOFTNET_UNLOCK();
    855 	return;
    856 
    857 out:
    858 	m_put_rcvif_psref(ifp, &psref);
    859 	if (m != NULL)
    860 		m_freem(m);
    861 }
    862 
    863 /*
    864  * IP timer processing.
    865  */
    866 void
    867 ip_slowtimo(void)
    868 {
    869 
    870 	mutex_enter(softnet_lock);
    871 	KERNEL_LOCK(1, NULL);
    872 
    873 	ip_reass_slowtimo();
    874 
    875 	KERNEL_UNLOCK_ONE(NULL);
    876 	mutex_exit(softnet_lock);
    877 }
    878 
    879 /*
    880  * IP drain processing.
    881  */
    882 void
    883 ip_drain(void)
    884 {
    885 
    886 	KERNEL_LOCK(1, NULL);
    887 	ip_reass_drain();
    888 	KERNEL_UNLOCK_ONE(NULL);
    889 }
    890 
    891 /*
    892  * ip_dooptions: perform option processing on a datagram, possibly discarding
    893  * it if bad options are encountered, or forwarding it if source-routed.
    894  *
    895  * => Returns true if packet has been forwarded/freed.
    896  * => Returns false if the packet should be processed further.
    897  */
    898 static bool
    899 ip_dooptions(struct mbuf *m)
    900 {
    901 	struct ip *ip = mtod(m, struct ip *);
    902 	u_char *cp, *cp0;
    903 	struct ip_timestamp *ipt;
    904 	struct in_ifaddr *ia;
    905 	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
    906 	struct in_addr dst;
    907 	n_time ntime;
    908 	struct ifaddr *ifa;
    909 	int s;
    910 
    911 	dst = ip->ip_dst;
    912 	cp = (u_char *)(ip + 1);
    913 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
    914 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
    915 		opt = cp[IPOPT_OPTVAL];
    916 		if (opt == IPOPT_EOL)
    917 			break;
    918 		if (opt == IPOPT_NOP)
    919 			optlen = 1;
    920 		else {
    921 			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
    922 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    923 				goto bad;
    924 			}
    925 			optlen = cp[IPOPT_OLEN];
    926 			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
    927 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    928 				goto bad;
    929 			}
    930 		}
    931 		switch (opt) {
    932 
    933 		default:
    934 			break;
    935 
    936 		/*
    937 		 * Source routing with record.
    938 		 * Find interface with current destination address.
    939 		 * If none on this machine then drop if strictly routed,
    940 		 * or do nothing if loosely routed.
    941 		 * Record interface address and bring up next address
    942 		 * component.  If strictly routed make sure next
    943 		 * address is on directly accessible net.
    944 		 */
    945 		case IPOPT_LSRR:
    946 		case IPOPT_SSRR:
    947 			if (ip_allowsrcrt == 0) {
    948 				type = ICMP_UNREACH;
    949 				code = ICMP_UNREACH_NET_PROHIB;
    950 				goto bad;
    951 			}
    952 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
    953 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    954 				goto bad;
    955 			}
    956 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
    957 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
    958 				goto bad;
    959 			}
    960 			ipaddr.sin_addr = ip->ip_dst;
    961 
    962 			s = pserialize_read_enter();
    963 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
    964 			if (ifa == NULL) {
    965 				pserialize_read_exit(s);
    966 				if (opt == IPOPT_SSRR) {
    967 					type = ICMP_UNREACH;
    968 					code = ICMP_UNREACH_SRCFAIL;
    969 					goto bad;
    970 				}
    971 				/*
    972 				 * Loose routing, and not at next destination
    973 				 * yet; nothing to do except forward.
    974 				 */
    975 				break;
    976 			}
    977 			pserialize_read_exit(s);
    978 
    979 			off--;			/* 0 origin */
    980 			if ((off + sizeof(struct in_addr)) > optlen) {
    981 				/*
    982 				 * End of source route.  Should be for us.
    983 				 */
    984 				save_rte(cp, ip->ip_src);
    985 				break;
    986 			}
    987 			/*
    988 			 * locate outgoing interface
    989 			 */
    990 			memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
    991 			    sizeof(ipaddr.sin_addr));
    992 			s = pserialize_read_enter();
    993 			if (opt == IPOPT_SSRR) {
    994 				ifa = ifa_ifwithladdr(sintosa(&ipaddr));
    995 				if (ifa != NULL)
    996 					ia = ifatoia(ifa);
    997 				else
    998 					ia = NULL;
    999 			} else {
   1000 				ia = ip_rtaddr(ipaddr.sin_addr);
   1001 			}
   1002 			if (ia == NULL) {
   1003 				type = ICMP_UNREACH;
   1004 				code = ICMP_UNREACH_SRCFAIL;
   1005 				pserialize_read_exit(s);
   1006 				goto bad;
   1007 			}
   1008 			ip->ip_dst = ipaddr.sin_addr;
   1009 			bcopy((void *)&ia->ia_addr.sin_addr,
   1010 			    (void *)(cp + off), sizeof(struct in_addr));
   1011 			pserialize_read_exit(s);
   1012 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1013 			/*
   1014 			 * Let ip_intr's mcast routing check handle mcast pkts
   1015 			 */
   1016 			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
   1017 			break;
   1018 
   1019 		case IPOPT_RR:
   1020 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
   1021 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
   1022 				goto bad;
   1023 			}
   1024 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
   1025 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
   1026 				goto bad;
   1027 			}
   1028 			/*
   1029 			 * If no space remains, ignore.
   1030 			 */
   1031 			off--;			/* 0 origin */
   1032 			if ((off + sizeof(struct in_addr)) > optlen)
   1033 				break;
   1034 			memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
   1035 			    sizeof(ipaddr.sin_addr));
   1036 			/*
   1037 			 * locate outgoing interface; if we're the destination,
   1038 			 * use the incoming interface (should be same).
   1039 			 */
   1040 			s = pserialize_read_enter();
   1041 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
   1042 			if (ifa == NULL) {
   1043 				ia = ip_rtaddr(ipaddr.sin_addr);
   1044 				if (ia == NULL) {
   1045 					pserialize_read_exit(s);
   1046 					type = ICMP_UNREACH;
   1047 					code = ICMP_UNREACH_HOST;
   1048 					goto bad;
   1049 				}
   1050 			} else {
   1051 				ia = ifatoia(ifa);
   1052 			}
   1053 			bcopy((void *)&ia->ia_addr.sin_addr,
   1054 			    (void *)(cp + off), sizeof(struct in_addr));
   1055 			pserialize_read_exit(s);
   1056 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1057 			break;
   1058 
   1059 		case IPOPT_TS:
   1060 			code = cp - (u_char *)ip;
   1061 			ipt = (struct ip_timestamp *)cp;
   1062 			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
   1063 				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
   1064 				goto bad;
   1065 			}
   1066 			if (ipt->ipt_ptr < 5) {
   1067 				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
   1068 				goto bad;
   1069 			}
   1070 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
   1071 				if (++ipt->ipt_oflw == 0) {
   1072 					code = (u_char *)&ipt->ipt_ptr -
   1073 					    (u_char *)ip;
   1074 					goto bad;
   1075 				}
   1076 				break;
   1077 			}
   1078 			cp0 = (cp + ipt->ipt_ptr - 1);
   1079 			switch (ipt->ipt_flg) {
   1080 
   1081 			case IPOPT_TS_TSONLY:
   1082 				break;
   1083 
   1084 			case IPOPT_TS_TSANDADDR: {
   1085 				struct ifnet *rcvif;
   1086 				int _s, _ss;
   1087 
   1088 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1089 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1090 					code = (u_char *)&ipt->ipt_ptr -
   1091 					    (u_char *)ip;
   1092 					goto bad;
   1093 				}
   1094 				ipaddr.sin_addr = dst;
   1095 				_ss = pserialize_read_enter();
   1096 				rcvif = m_get_rcvif(m, &_s);
   1097 				ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif);
   1098 				m_put_rcvif(rcvif, &_s);
   1099 				if (ifa == NULL) {
   1100 					pserialize_read_exit(_ss);
   1101 					break;
   1102 				}
   1103 				ia = ifatoia(ifa);
   1104 				bcopy(&ia->ia_addr.sin_addr,
   1105 				    cp0, sizeof(struct in_addr));
   1106 				pserialize_read_exit(_ss);
   1107 				ipt->ipt_ptr += sizeof(struct in_addr);
   1108 				break;
   1109 			}
   1110 
   1111 			case IPOPT_TS_PRESPEC:
   1112 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1113 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1114 					code = (u_char *)&ipt->ipt_ptr -
   1115 					    (u_char *)ip;
   1116 					goto bad;
   1117 				}
   1118 				memcpy(&ipaddr.sin_addr, cp0,
   1119 				    sizeof(struct in_addr));
   1120 				s = pserialize_read_enter();
   1121 				ifa = ifa_ifwithaddr(sintosa(&ipaddr));
   1122 				if (ifa == NULL) {
   1123 					pserialize_read_exit(s);
   1124 					continue;
   1125 				}
   1126 				pserialize_read_exit(s);
   1127 				ipt->ipt_ptr += sizeof(struct in_addr);
   1128 				break;
   1129 
   1130 			default:
   1131 				/* XXX can't take &ipt->ipt_flg */
   1132 				code = (u_char *)&ipt->ipt_ptr -
   1133 				    (u_char *)ip + 1;
   1134 				goto bad;
   1135 			}
   1136 			ntime = iptime();
   1137 			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
   1138 			memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
   1139 			    sizeof(n_time));
   1140 			ipt->ipt_ptr += sizeof(n_time);
   1141 		}
   1142 	}
   1143 	if (forward) {
   1144 		struct ifnet *rcvif;
   1145 		struct psref _psref;
   1146 
   1147 		if (ip_forwsrcrt == 0) {
   1148 			type = ICMP_UNREACH;
   1149 			code = ICMP_UNREACH_SRCFAIL;
   1150 			goto bad;
   1151 		}
   1152 
   1153 		rcvif = m_get_rcvif_psref(m, &_psref);
   1154 		if (__predict_false(rcvif == NULL)) {
   1155 			type = ICMP_UNREACH;
   1156 			code = ICMP_UNREACH_HOST;
   1157 			goto bad;
   1158 		}
   1159 		ip_forward(m, 1, rcvif);
   1160 		m_put_rcvif_psref(rcvif, &_psref);
   1161 		return true;
   1162 	}
   1163 	return false;
   1164 bad:
   1165 	icmp_error(m, type, code, 0, 0);
   1166 	IP_STATINC(IP_STAT_BADOPTIONS);
   1167 	return true;
   1168 }
   1169 
   1170 /*
   1171  * ip_rtaddr: given address of next destination (final or next hop),
   1172  * return internet address info of interface to be used to get there.
   1173  */
   1174 static struct in_ifaddr *
   1175 ip_rtaddr(struct in_addr dst)
   1176 {
   1177 	struct rtentry *rt;
   1178 	union {
   1179 		struct sockaddr		dst;
   1180 		struct sockaddr_in	dst4;
   1181 	} u;
   1182 	struct route *ro;
   1183 
   1184 	sockaddr_in_init(&u.dst4, &dst, 0);
   1185 
   1186 	ro = percpu_getref(ipforward_rt_percpu);
   1187 	rt = rtcache_lookup(ro, &u.dst);
   1188 	if (rt == NULL) {
   1189 		percpu_putref(ipforward_rt_percpu);
   1190 		return NULL;
   1191 	}
   1192 
   1193 	rtcache_unref(rt, ro);
   1194 	percpu_putref(ipforward_rt_percpu);
   1195 
   1196 	return ifatoia(rt->rt_ifa);
   1197 }
   1198 
   1199 /*
   1200  * save_rte: save incoming source route for use in replies, to be picked
   1201  * up later by ip_srcroute if the receiver is interested.
   1202  */
   1203 static void
   1204 save_rte(u_char *option, struct in_addr dst)
   1205 {
   1206 	unsigned olen;
   1207 
   1208 	olen = option[IPOPT_OLEN];
   1209 	if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
   1210 		return;
   1211 	memcpy((void *)ip_srcrt.srcopt, (void *)option, olen);
   1212 	ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
   1213 	ip_srcrt.dst = dst;
   1214 }
   1215 
   1216 /*
   1217  * Retrieve incoming source route for use in replies,
   1218  * in the same form used by setsockopt.
   1219  * The first hop is placed before the options, will be removed later.
   1220  */
   1221 struct mbuf *
   1222 ip_srcroute(void)
   1223 {
   1224 	struct in_addr *p, *q;
   1225 	struct mbuf *m;
   1226 
   1227 	if (ip_nhops == 0)
   1228 		return NULL;
   1229 	m = m_get(M_DONTWAIT, MT_SOOPTS);
   1230 	if (m == 0)
   1231 		return NULL;
   1232 
   1233 	MCLAIM(m, &inetdomain.dom_mowner);
   1234 #define OPTSIZ	(sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
   1235 
   1236 	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
   1237 	m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
   1238 	    OPTSIZ;
   1239 
   1240 	/*
   1241 	 * First save first hop for return route
   1242 	 */
   1243 	p = &ip_srcrt.route[ip_nhops - 1];
   1244 	*(mtod(m, struct in_addr *)) = *p--;
   1245 
   1246 	/*
   1247 	 * Copy option fields and padding (nop) to mbuf.
   1248 	 */
   1249 	ip_srcrt.nop = IPOPT_NOP;
   1250 	ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
   1251 	memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop,
   1252 	    OPTSIZ);
   1253 	q = (struct in_addr *)(mtod(m, char *) +
   1254 	    sizeof(struct in_addr) + OPTSIZ);
   1255 #undef OPTSIZ
   1256 	/*
   1257 	 * Record return path as an IP source route,
   1258 	 * reversing the path (pointers are now aligned).
   1259 	 */
   1260 	while (p >= ip_srcrt.route) {
   1261 		*q++ = *p--;
   1262 	}
   1263 	/*
   1264 	 * Last hop goes to final destination.
   1265 	 */
   1266 	*q = ip_srcrt.dst;
   1267 	return (m);
   1268 }
   1269 
   1270 const int inetctlerrmap[PRC_NCMDS] = {
   1271 	[PRC_MSGSIZE] = EMSGSIZE,
   1272 	[PRC_HOSTDEAD] = EHOSTDOWN,
   1273 	[PRC_HOSTUNREACH] = EHOSTUNREACH,
   1274 	[PRC_UNREACH_NET] = EHOSTUNREACH,
   1275 	[PRC_UNREACH_HOST] = EHOSTUNREACH,
   1276 	[PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
   1277 	[PRC_UNREACH_PORT] = ECONNREFUSED,
   1278 	[PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
   1279 	[PRC_PARAMPROB] = ENOPROTOOPT,
   1280 };
   1281 
   1282 void
   1283 ip_fasttimo(void)
   1284 {
   1285 	if (ip_drainwanted) {
   1286 		ip_drain();
   1287 		ip_drainwanted = 0;
   1288 	}
   1289 }
   1290 
   1291 void
   1292 ip_drainstub(void)
   1293 {
   1294 	ip_drainwanted = 1;
   1295 }
   1296 
   1297 /*
   1298  * Forward a packet.  If some error occurs return the sender
   1299  * an icmp packet.  Note we can't always generate a meaningful
   1300  * icmp message because icmp doesn't have a large enough repertoire
   1301  * of codes and types.
   1302  *
   1303  * If not forwarding, just drop the packet.  This could be confusing
   1304  * if ipforwarding was zero but some routing protocol was advancing
   1305  * us as a gateway to somewhere.  However, we must let the routing
   1306  * protocol deal with that.
   1307  *
   1308  * The srcrt parameter indicates whether the packet is being forwarded
   1309  * via a source route.
   1310  */
   1311 static void
   1312 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif)
   1313 {
   1314 	struct ip *ip = mtod(m, struct ip *);
   1315 	struct rtentry *rt;
   1316 	int error, type = 0, code = 0, destmtu = 0;
   1317 	struct mbuf *mcopy;
   1318 	n_long dest;
   1319 	union {
   1320 		struct sockaddr		dst;
   1321 		struct sockaddr_in	dst4;
   1322 	} u;
   1323 	uint64_t *ips;
   1324 	struct route *ro;
   1325 
   1326 	KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software "
   1327 	    "interrupt handler; synchronization assumptions violated");
   1328 
   1329 	/*
   1330 	 * We are now in the output path.
   1331 	 */
   1332 	MCLAIM(m, &ip_tx_mowner);
   1333 
   1334 	/*
   1335 	 * Clear any in-bound checksum flags for this packet.
   1336 	 */
   1337 	m->m_pkthdr.csum_flags = 0;
   1338 
   1339 	dest = 0;
   1340 	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
   1341 		IP_STATINC(IP_STAT_CANTFORWARD);
   1342 		m_freem(m);
   1343 		return;
   1344 	}
   1345 
   1346 	if (ip->ip_ttl <= IPTTLDEC) {
   1347 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
   1348 		return;
   1349 	}
   1350 
   1351 	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
   1352 
   1353 	ro = percpu_getref(ipforward_rt_percpu);
   1354 	rt = rtcache_lookup(ro, &u.dst);
   1355 	if (rt == NULL) {
   1356 		percpu_putref(ipforward_rt_percpu);
   1357 		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
   1358 		return;
   1359 	}
   1360 
   1361 	/*
   1362 	 * Save at most 68 bytes of the packet in case
   1363 	 * we need to generate an ICMP message to the src.
   1364 	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
   1365 	 */
   1366 	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
   1367 	if (mcopy)
   1368 		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
   1369 
   1370 	ip->ip_ttl -= IPTTLDEC;
   1371 
   1372 	/*
   1373 	 * If forwarding packet using same interface that it came in on,
   1374 	 * perhaps should send a redirect to sender to shortcut a hop.
   1375 	 * Only send redirect if source is sending directly to us,
   1376 	 * and if packet was not source routed (or has any options).
   1377 	 * Also, don't send redirect if forwarding using a default route
   1378 	 * or a route modified by a redirect.
   1379 	 */
   1380 	if (rt->rt_ifp == rcvif &&
   1381 	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
   1382 	    !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
   1383 	    ipsendredirects && !srcrt) {
   1384 		if (rt->rt_ifa &&
   1385 		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
   1386 		    ifatoia(rt->rt_ifa)->ia_subnet) {
   1387 			if (rt->rt_flags & RTF_GATEWAY)
   1388 				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
   1389 			else
   1390 				dest = ip->ip_dst.s_addr;
   1391 			/*
   1392 			 * Router requirements says to only send host
   1393 			 * redirects.
   1394 			 */
   1395 			type = ICMP_REDIRECT;
   1396 			code = ICMP_REDIRECT_HOST;
   1397 		}
   1398 	}
   1399 	rtcache_unref(rt, ro);
   1400 
   1401 	error = ip_output(m, NULL, ro,
   1402 	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
   1403 	    NULL, NULL);
   1404 
   1405 	if (error) {
   1406 		IP_STATINC(IP_STAT_CANTFORWARD);
   1407 		goto error;
   1408 	}
   1409 
   1410 	ips = IP_STAT_GETREF();
   1411 	ips[IP_STAT_FORWARD]++;
   1412 
   1413 	if (type) {
   1414 		ips[IP_STAT_REDIRECTSENT]++;
   1415 		IP_STAT_PUTREF();
   1416 		goto redirect;
   1417 	}
   1418 
   1419 	IP_STAT_PUTREF();
   1420 	if (mcopy) {
   1421 #ifdef GATEWAY
   1422 		if (mcopy->m_flags & M_CANFASTFWD)
   1423 			ipflow_create(ro, mcopy);
   1424 #endif
   1425 		m_freem(mcopy);
   1426 	}
   1427 
   1428 	percpu_putref(ipforward_rt_percpu);
   1429 	return;
   1430 
   1431 redirect:
   1432 error:
   1433 	if (mcopy == NULL) {
   1434 		percpu_putref(ipforward_rt_percpu);
   1435 		return;
   1436 	}
   1437 
   1438 	switch (error) {
   1439 
   1440 	case 0:				/* forwarded, but need redirect */
   1441 		/* type, code set above */
   1442 		break;
   1443 
   1444 	case ENETUNREACH:		/* shouldn't happen, checked above */
   1445 	case EHOSTUNREACH:
   1446 	case ENETDOWN:
   1447 	case EHOSTDOWN:
   1448 	default:
   1449 		type = ICMP_UNREACH;
   1450 		code = ICMP_UNREACH_HOST;
   1451 		break;
   1452 
   1453 	case EMSGSIZE:
   1454 		type = ICMP_UNREACH;
   1455 		code = ICMP_UNREACH_NEEDFRAG;
   1456 
   1457 		if ((rt = rtcache_validate(ro)) != NULL) {
   1458 			destmtu = rt->rt_ifp->if_mtu;
   1459 			rtcache_unref(rt, ro);
   1460 		}
   1461 #ifdef IPSEC
   1462 		if (ipsec_used)
   1463 			(void)ipsec4_forward(mcopy, &destmtu);
   1464 #endif
   1465 		IP_STATINC(IP_STAT_CANTFRAG);
   1466 		break;
   1467 
   1468 	case ENOBUFS:
   1469 		/*
   1470 		 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812,
   1471 		 * Requirements for IP Version 4 Routers.  Source quench can
   1472 		 * big problem under DoS attacks or if the underlying
   1473 		 * interface is rate-limited.
   1474 		 */
   1475 		if (mcopy)
   1476 			m_freem(mcopy);
   1477 		percpu_putref(ipforward_rt_percpu);
   1478 		return;
   1479 	}
   1480 	icmp_error(mcopy, type, code, dest, destmtu);
   1481 	percpu_putref(ipforward_rt_percpu);
   1482 }
   1483 
   1484 void
   1485 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
   1486     struct mbuf *m)
   1487 {
   1488 	struct socket *so = inp->inp_socket;
   1489 	ifnet_t *ifp;
   1490 	int inpflags = inp->inp_flags;
   1491 	struct psref psref;
   1492 
   1493 	ifp = m_get_rcvif_psref(m, &psref);
   1494 	if (__predict_false(ifp == NULL))
   1495 		return; /* XXX should report error? */
   1496 
   1497 	if (so->so_options & SO_TIMESTAMP
   1498 #ifdef SO_OTIMESTAMP
   1499 	    || so->so_options & SO_OTIMESTAMP
   1500 #endif
   1501 	    ) {
   1502 		struct timeval tv;
   1503 
   1504 		microtime(&tv);
   1505 #ifdef SO_OTIMESTAMP
   1506 		if (so->so_options & SO_OTIMESTAMP) {
   1507 			struct timeval50 tv50;
   1508 			timeval_to_timeval50(&tv, &tv50);
   1509 			*mp = sbcreatecontrol((void *) &tv50, sizeof(tv50),
   1510 			    SCM_OTIMESTAMP, SOL_SOCKET);
   1511 		} else
   1512 #endif
   1513 		*mp = sbcreatecontrol((void *) &tv, sizeof(tv),
   1514 		    SCM_TIMESTAMP, SOL_SOCKET);
   1515 		if (*mp)
   1516 			mp = &(*mp)->m_next;
   1517 	}
   1518 	if (inpflags & INP_RECVDSTADDR) {
   1519 		*mp = sbcreatecontrol((void *) &ip->ip_dst,
   1520 		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
   1521 		if (*mp)
   1522 			mp = &(*mp)->m_next;
   1523 	}
   1524 	if (inpflags & INP_RECVPKTINFO) {
   1525 		struct in_pktinfo ipi;
   1526 		ipi.ipi_addr = ip->ip_src;
   1527 		ipi.ipi_ifindex = ifp->if_index;
   1528 		*mp = sbcreatecontrol((void *) &ipi,
   1529 		    sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP);
   1530 		if (*mp)
   1531 			mp = &(*mp)->m_next;
   1532 	}
   1533 	if (inpflags & INP_PKTINFO) {
   1534 		struct in_pktinfo ipi;
   1535 		ipi.ipi_addr = ip->ip_dst;
   1536 		ipi.ipi_ifindex = ifp->if_index;
   1537 		*mp = sbcreatecontrol((void *) &ipi,
   1538 		    sizeof(ipi), IP_PKTINFO, IPPROTO_IP);
   1539 		if (*mp)
   1540 			mp = &(*mp)->m_next;
   1541 	}
   1542 	if (inpflags & INP_RECVIF) {
   1543 		struct sockaddr_dl sdl;
   1544 
   1545 		sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0,
   1546 		    NULL, 0);
   1547 		*mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
   1548 		if (*mp)
   1549 			mp = &(*mp)->m_next;
   1550 	}
   1551 	if (inpflags & INP_RECVTTL) {
   1552 		*mp = sbcreatecontrol((void *) &ip->ip_ttl,
   1553 		    sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
   1554 		if (*mp)
   1555 			mp = &(*mp)->m_next;
   1556 	}
   1557 	m_put_rcvif_psref(ifp, &psref);
   1558 }
   1559 
   1560 /*
   1561  * sysctl helper routine for net.inet.ip.forwsrcrt.
   1562  */
   1563 static int
   1564 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
   1565 {
   1566 	int error, tmp;
   1567 	struct sysctlnode node;
   1568 
   1569 	node = *rnode;
   1570 	tmp = ip_forwsrcrt;
   1571 	node.sysctl_data = &tmp;
   1572 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1573 	if (error || newp == NULL)
   1574 		return (error);
   1575 
   1576 	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
   1577 	    0, NULL, NULL, NULL);
   1578 	if (error)
   1579 		return (error);
   1580 
   1581 	ip_forwsrcrt = tmp;
   1582 
   1583 	return (0);
   1584 }
   1585 
   1586 /*
   1587  * sysctl helper routine for net.inet.ip.mtudisctimeout.  checks the
   1588  * range of the new value and tweaks timers if it changes.
   1589  */
   1590 static int
   1591 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
   1592 {
   1593 	int error, tmp;
   1594 	struct sysctlnode node;
   1595 
   1596 	node = *rnode;
   1597 	tmp = ip_mtudisc_timeout;
   1598 	node.sysctl_data = &tmp;
   1599 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1600 	if (error || newp == NULL)
   1601 		return (error);
   1602 	if (tmp < 0)
   1603 		return (EINVAL);
   1604 
   1605 	mutex_enter(softnet_lock);
   1606 
   1607 	ip_mtudisc_timeout = tmp;
   1608 	rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
   1609 
   1610 	mutex_exit(softnet_lock);
   1611 
   1612 	return (0);
   1613 }
   1614 
   1615 static int
   1616 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
   1617 {
   1618 
   1619 	return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
   1620 }
   1621 
   1622 static void
   1623 sysctl_net_inet_ip_setup(struct sysctllog **clog)
   1624 {
   1625 	sysctl_createv(clog, 0, NULL, NULL,
   1626 		       CTLFLAG_PERMANENT,
   1627 		       CTLTYPE_NODE, "inet",
   1628 		       SYSCTL_DESCR("PF_INET related settings"),
   1629 		       NULL, 0, NULL, 0,
   1630 		       CTL_NET, PF_INET, CTL_EOL);
   1631 	sysctl_createv(clog, 0, NULL, NULL,
   1632 		       CTLFLAG_PERMANENT,
   1633 		       CTLTYPE_NODE, "ip",
   1634 		       SYSCTL_DESCR("IPv4 related settings"),
   1635 		       NULL, 0, NULL, 0,
   1636 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
   1637 
   1638 	sysctl_createv(clog, 0, NULL, NULL,
   1639 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1640 		       CTLTYPE_INT, "forwarding",
   1641 		       SYSCTL_DESCR("Enable forwarding of INET datagrams"),
   1642 		       NULL, 0, &ipforwarding, 0,
   1643 		       CTL_NET, PF_INET, IPPROTO_IP,
   1644 		       IPCTL_FORWARDING, CTL_EOL);
   1645 	sysctl_createv(clog, 0, NULL, NULL,
   1646 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1647 		       CTLTYPE_INT, "redirect",
   1648 		       SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
   1649 		       NULL, 0, &ipsendredirects, 0,
   1650 		       CTL_NET, PF_INET, IPPROTO_IP,
   1651 		       IPCTL_SENDREDIRECTS, CTL_EOL);
   1652 	sysctl_createv(clog, 0, NULL, NULL,
   1653 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1654 		       CTLTYPE_INT, "ttl",
   1655 		       SYSCTL_DESCR("Default TTL for an INET datagram"),
   1656 		       NULL, 0, &ip_defttl, 0,
   1657 		       CTL_NET, PF_INET, IPPROTO_IP,
   1658 		       IPCTL_DEFTTL, CTL_EOL);
   1659 #ifdef IPCTL_DEFMTU
   1660 	sysctl_createv(clog, 0, NULL, NULL,
   1661 		       CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
   1662 		       CTLTYPE_INT, "mtu",
   1663 		       SYSCTL_DESCR("Default MTA for an INET route"),
   1664 		       NULL, 0, &ip_mtu, 0,
   1665 		       CTL_NET, PF_INET, IPPROTO_IP,
   1666 		       IPCTL_DEFMTU, CTL_EOL);
   1667 #endif /* IPCTL_DEFMTU */
   1668 	sysctl_createv(clog, 0, NULL, NULL,
   1669 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1670 		       CTLTYPE_INT, "forwsrcrt",
   1671 		       SYSCTL_DESCR("Enable forwarding of source-routed "
   1672 				    "datagrams"),
   1673 		       sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
   1674 		       CTL_NET, PF_INET, IPPROTO_IP,
   1675 		       IPCTL_FORWSRCRT, CTL_EOL);
   1676 	sysctl_createv(clog, 0, NULL, NULL,
   1677 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1678 		       CTLTYPE_INT, "directed-broadcast",
   1679 		       SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
   1680 		       NULL, 0, &ip_directedbcast, 0,
   1681 		       CTL_NET, PF_INET, IPPROTO_IP,
   1682 		       IPCTL_DIRECTEDBCAST, CTL_EOL);
   1683 	sysctl_createv(clog, 0, NULL, NULL,
   1684 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1685 		       CTLTYPE_INT, "allowsrcrt",
   1686 		       SYSCTL_DESCR("Accept source-routed datagrams"),
   1687 		       NULL, 0, &ip_allowsrcrt, 0,
   1688 		       CTL_NET, PF_INET, IPPROTO_IP,
   1689 		       IPCTL_ALLOWSRCRT, CTL_EOL);
   1690 
   1691 	sysctl_createv(clog, 0, NULL, NULL,
   1692 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1693 		       CTLTYPE_INT, "mtudisc",
   1694 		       SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
   1695 		       NULL, 0, &ip_mtudisc, 0,
   1696 		       CTL_NET, PF_INET, IPPROTO_IP,
   1697 		       IPCTL_MTUDISC, CTL_EOL);
   1698 	sysctl_createv(clog, 0, NULL, NULL,
   1699 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1700 		       CTLTYPE_INT, "anonportmin",
   1701 		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
   1702 		       sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
   1703 		       CTL_NET, PF_INET, IPPROTO_IP,
   1704 		       IPCTL_ANONPORTMIN, CTL_EOL);
   1705 	sysctl_createv(clog, 0, NULL, NULL,
   1706 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1707 		       CTLTYPE_INT, "anonportmax",
   1708 		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
   1709 		       sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
   1710 		       CTL_NET, PF_INET, IPPROTO_IP,
   1711 		       IPCTL_ANONPORTMAX, CTL_EOL);
   1712 	sysctl_createv(clog, 0, NULL, NULL,
   1713 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1714 		       CTLTYPE_INT, "mtudisctimeout",
   1715 		       SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
   1716 		       sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0,
   1717 		       CTL_NET, PF_INET, IPPROTO_IP,
   1718 		       IPCTL_MTUDISCTIMEOUT, CTL_EOL);
   1719 #ifndef IPNOPRIVPORTS
   1720 	sysctl_createv(clog, 0, NULL, NULL,
   1721 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1722 		       CTLTYPE_INT, "lowportmin",
   1723 		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
   1724 				    "to assign"),
   1725 		       sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
   1726 		       CTL_NET, PF_INET, IPPROTO_IP,
   1727 		       IPCTL_LOWPORTMIN, CTL_EOL);
   1728 	sysctl_createv(clog, 0, NULL, NULL,
   1729 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1730 		       CTLTYPE_INT, "lowportmax",
   1731 		       SYSCTL_DESCR("Highest privileged ephemeral port number "
   1732 				    "to assign"),
   1733 		       sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
   1734 		       CTL_NET, PF_INET, IPPROTO_IP,
   1735 		       IPCTL_LOWPORTMAX, CTL_EOL);
   1736 #endif /* IPNOPRIVPORTS */
   1737 #if NGRE > 0
   1738 	sysctl_createv(clog, 0, NULL, NULL,
   1739 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1740 		       CTLTYPE_INT, "grettl",
   1741 		       SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
   1742 		       NULL, 0, &ip_gre_ttl, 0,
   1743 		       CTL_NET, PF_INET, IPPROTO_IP,
   1744 		       IPCTL_GRE_TTL, CTL_EOL);
   1745 #endif /* NGRE */
   1746 	sysctl_createv(clog, 0, NULL, NULL,
   1747 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1748 		       CTLTYPE_INT, "checkinterface",
   1749 		       SYSCTL_DESCR("Enable receive side of Strong ES model "
   1750 				    "from RFC1122"),
   1751 		       NULL, 0, &ip_checkinterface, 0,
   1752 		       CTL_NET, PF_INET, IPPROTO_IP,
   1753 		       IPCTL_CHECKINTERFACE, CTL_EOL);
   1754 	sysctl_createv(clog, 0, NULL, NULL,
   1755 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1756 		       CTLTYPE_INT, "random_id",
   1757 		       SYSCTL_DESCR("Assign random ip_id values"),
   1758 		       NULL, 0, &ip_do_randomid, 0,
   1759 		       CTL_NET, PF_INET, IPPROTO_IP,
   1760 		       IPCTL_RANDOMID, CTL_EOL);
   1761 	sysctl_createv(clog, 0, NULL, NULL,
   1762 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1763 		       CTLTYPE_INT, "do_loopback_cksum",
   1764 		       SYSCTL_DESCR("Perform IP checksum on loopback"),
   1765 		       NULL, 0, &ip_do_loopback_cksum, 0,
   1766 		       CTL_NET, PF_INET, IPPROTO_IP,
   1767 		       IPCTL_LOOPBACKCKSUM, CTL_EOL);
   1768 	sysctl_createv(clog, 0, NULL, NULL,
   1769 		       CTLFLAG_PERMANENT,
   1770 		       CTLTYPE_STRUCT, "stats",
   1771 		       SYSCTL_DESCR("IP statistics"),
   1772 		       sysctl_net_inet_ip_stats, 0, NULL, 0,
   1773 		       CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
   1774 		       CTL_EOL);
   1775 #if NARP
   1776 	sysctl_createv(clog, 0, NULL, NULL,
   1777 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1778 		       CTLTYPE_INT, "dad_count",
   1779 		       SYSCTL_DESCR("Number of Duplicate Address Detection "
   1780 				    "probes to send"),
   1781 		       NULL, 0, &ip_dad_count, 0,
   1782 		       CTL_NET, PF_INET, IPPROTO_IP,
   1783 		       IPCTL_DAD_COUNT, CTL_EOL);
   1784 #endif
   1785 
   1786 	/* anonportalgo RFC6056 subtree */
   1787 	const struct sysctlnode *portalgo_node;
   1788 	sysctl_createv(clog, 0, NULL, &portalgo_node,
   1789 		       CTLFLAG_PERMANENT,
   1790 		       CTLTYPE_NODE, "anonportalgo",
   1791 		       SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"),
   1792 	    	       NULL, 0, NULL, 0,
   1793 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL);
   1794 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1795 		       CTLFLAG_PERMANENT,
   1796 		       CTLTYPE_STRING, "available",
   1797 		       SYSCTL_DESCR("available algorithms"),
   1798 		       sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
   1799 		       CTL_CREATE, CTL_EOL);
   1800 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1801 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1802 		       CTLTYPE_STRING, "selected",
   1803 		       SYSCTL_DESCR("selected algorithm"),
   1804 		       sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN,
   1805 		       CTL_CREATE, CTL_EOL);
   1806 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1807 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1808 		       CTLTYPE_STRUCT, "reserve",
   1809 		       SYSCTL_DESCR("bitmap of reserved ports"),
   1810 		       sysctl_portalgo_reserve4, 0, NULL, 0,
   1811 		       CTL_CREATE, CTL_EOL);
   1812 }
   1813 
   1814 void
   1815 ip_statinc(u_int stat)
   1816 {
   1817 
   1818 	KASSERT(stat < IP_NSTATS);
   1819 	IP_STATINC(stat);
   1820 }
   1821