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ip_input.c revision 1.359
      1 /*	$NetBSD: ip_input.c,v 1.359 2017/07/19 07:24:46 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 1.359 2017/07/19 07:24:46 ozaki-r Exp $");
     95 
     96 #ifdef _KERNEL_OPT
     97 #include "opt_inet.h"
     98 #include "opt_gateway.h"
     99 #include "opt_ipsec.h"
    100 #include "opt_mrouting.h"
    101 #include "opt_mbuftrace.h"
    102 #include "opt_inet_csum.h"
    103 #include "opt_net_mpsafe.h"
    104 #endif
    105 
    106 #include "arp.h"
    107 
    108 #include <sys/param.h>
    109 #include <sys/systm.h>
    110 #include <sys/cpu.h>
    111 #include <sys/mbuf.h>
    112 #include <sys/domain.h>
    113 #include <sys/protosw.h>
    114 #include <sys/socket.h>
    115 #include <sys/socketvar.h>
    116 #include <sys/errno.h>
    117 #include <sys/time.h>
    118 #include <sys/kernel.h>
    119 #include <sys/pool.h>
    120 #include <sys/sysctl.h>
    121 #include <sys/kauth.h>
    122 
    123 #include <net/if.h>
    124 #include <net/if_dl.h>
    125 #include <net/route.h>
    126 #include <net/pktqueue.h>
    127 #include <net/pfil.h>
    128 
    129 #include <netinet/in.h>
    130 #include <netinet/in_systm.h>
    131 #include <netinet/ip.h>
    132 #include <netinet/in_pcb.h>
    133 #include <netinet/in_proto.h>
    134 #include <netinet/in_var.h>
    135 #include <netinet/ip_var.h>
    136 #include <netinet/ip_private.h>
    137 #include <netinet/ip_icmp.h>
    138 /* just for gif_ttl */
    139 #include <netinet/in_gif.h>
    140 #include "gif.h"
    141 #include <net/if_gre.h>
    142 #include "gre.h"
    143 
    144 #ifdef MROUTING
    145 #include <netinet/ip_mroute.h>
    146 #endif
    147 #include <netinet/portalgo.h>
    148 
    149 #ifdef IPSEC
    150 #include <netipsec/ipsec.h>
    151 #endif
    152 
    153 #ifndef	IPFORWARDING
    154 #ifdef GATEWAY
    155 #define	IPFORWARDING	1	/* forward IP packets not for us */
    156 #else /* GATEWAY */
    157 #define	IPFORWARDING	0	/* don't forward IP packets not for us */
    158 #endif /* GATEWAY */
    159 #endif /* IPFORWARDING */
    160 #ifndef	IPSENDREDIRECTS
    161 #define	IPSENDREDIRECTS	1
    162 #endif
    163 #ifndef IPFORWSRCRT
    164 #define	IPFORWSRCRT	1	/* forward source-routed packets */
    165 #endif
    166 #ifndef IPALLOWSRCRT
    167 #define	IPALLOWSRCRT	1	/* allow source-routed packets */
    168 #endif
    169 #ifndef IPMTUDISC
    170 #define IPMTUDISC	1
    171 #endif
    172 #ifndef IPMTUDISCTIMEOUT
    173 #define IPMTUDISCTIMEOUT (10 * 60)	/* as per RFC 1191 */
    174 #endif
    175 
    176 /*
    177  * Note: DIRECTED_BROADCAST is handled this way so that previous
    178  * configuration using this option will Just Work.
    179  */
    180 #ifndef IPDIRECTEDBCAST
    181 #ifdef DIRECTED_BROADCAST
    182 #define IPDIRECTEDBCAST	1
    183 #else
    184 #define	IPDIRECTEDBCAST	0
    185 #endif /* DIRECTED_BROADCAST */
    186 #endif /* IPDIRECTEDBCAST */
    187 int	ipforwarding = IPFORWARDING;
    188 int	ipsendredirects = IPSENDREDIRECTS;
    189 int	ip_defttl = IPDEFTTL;
    190 int	ip_forwsrcrt = IPFORWSRCRT;
    191 int	ip_directedbcast = IPDIRECTEDBCAST;
    192 int	ip_allowsrcrt = IPALLOWSRCRT;
    193 int	ip_mtudisc = IPMTUDISC;
    194 int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
    195 #ifdef DIAGNOSTIC
    196 int	ipprintfs = 0;
    197 #endif
    198 
    199 int	ip_do_randomid = 0;
    200 
    201 /*
    202  * XXX - Setting ip_checkinterface mostly implements the receive side of
    203  * the Strong ES model described in RFC 1122, but since the routing table
    204  * and transmit implementation do not implement the Strong ES model,
    205  * setting this to 1 results in an odd hybrid.
    206  *
    207  * XXX - ip_checkinterface currently must be disabled if you use ipnat
    208  * to translate the destination address to another local interface.
    209  *
    210  * XXX - ip_checkinterface must be disabled if you add IP aliases
    211  * to the loopback interface instead of the interface where the
    212  * packets for those addresses are received.
    213  */
    214 static int		ip_checkinterface	__read_mostly = 0;
    215 
    216 struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
    217 
    218 pktqueue_t *		ip_pktq			__read_mostly;
    219 pfil_head_t *		inet_pfil_hook		__read_mostly;
    220 ipid_state_t *		ip_ids			__read_mostly;
    221 percpu_t *		ipstat_percpu		__read_mostly;
    222 
    223 static percpu_t		*ipforward_rt_percpu	__cacheline_aligned;
    224 
    225 uint16_t ip_id;
    226 
    227 #ifdef INET_CSUM_COUNTERS
    228 #include <sys/device.h>
    229 
    230 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    231     NULL, "inet", "hwcsum bad");
    232 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    233     NULL, "inet", "hwcsum ok");
    234 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    235     NULL, "inet", "swcsum");
    236 
    237 #define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
    238 
    239 EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
    240 EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
    241 EVCNT_ATTACH_STATIC(ip_swcsum);
    242 
    243 #else
    244 
    245 #define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
    246 
    247 #endif /* INET_CSUM_COUNTERS */
    248 
    249 /*
    250  * Used to save the IP options in case a protocol wants to respond
    251  * to an incoming packet over the same route if the packet got here
    252  * using IP source routing.  This allows connection establishment and
    253  * maintenance when the remote end is on a network that is not known
    254  * to us.
    255  */
    256 struct ip_srcrt {
    257 	int		isr_nhops;		   /* number of hops */
    258 	struct in_addr	isr_dst;		   /* final destination */
    259 	char		isr_nop;		   /* one NOP to align */
    260 	char		isr_hdr[IPOPT_OFFSET + 1]; /* OPTVAL, OLEN & OFFSET */
    261 	struct in_addr	isr_routes[MAX_IPOPTLEN/sizeof(struct in_addr)];
    262 };
    263 
    264 static int ip_drainwanted;
    265 
    266 static void save_rte(struct mbuf *, u_char *, struct in_addr);
    267 
    268 #ifdef MBUFTRACE
    269 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
    270 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
    271 #endif
    272 
    273 static void		ipintr(void *);
    274 static void		ip_input(struct mbuf *);
    275 static void		ip_forward(struct mbuf *, int, struct ifnet *);
    276 static bool		ip_dooptions(struct mbuf *);
    277 static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *);
    278 static void		sysctl_net_inet_ip_setup(struct sysctllog **);
    279 
    280 static struct in_ifaddr	*ip_match_our_address(struct ifnet *, struct ip *,
    281 			    int *);
    282 static struct in_ifaddr	*ip_match_our_address_broadcast(struct ifnet *,
    283 			    struct ip *);
    284 
    285 #ifdef NET_MPSAFE
    286 #define	SOFTNET_LOCK()		mutex_enter(softnet_lock)
    287 #define	SOFTNET_UNLOCK()	mutex_exit(softnet_lock)
    288 #else
    289 #define	SOFTNET_LOCK()		KASSERT(mutex_owned(softnet_lock))
    290 #define	SOFTNET_UNLOCK()	KASSERT(mutex_owned(softnet_lock))
    291 #endif
    292 
    293 /*
    294  * IP initialization: fill in IP protocol switch table.
    295  * All protocols not implemented in kernel go to raw IP protocol handler.
    296  */
    297 void
    298 ip_init(void)
    299 {
    300 	const struct protosw *pr;
    301 
    302 	in_init();
    303 	sysctl_net_inet_ip_setup(NULL);
    304 
    305 	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
    306 	KASSERT(pr != NULL);
    307 
    308 	ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL);
    309 	KASSERT(ip_pktq != NULL);
    310 
    311 	for (u_int i = 0; i < IPPROTO_MAX; i++) {
    312 		ip_protox[i] = pr - inetsw;
    313 	}
    314 	for (pr = inetdomain.dom_protosw;
    315 	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
    316 		if (pr->pr_domain->dom_family == PF_INET &&
    317 		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
    318 			ip_protox[pr->pr_protocol] = pr - inetsw;
    319 
    320 	ip_reass_init();
    321 
    322 	ip_ids = ip_id_init();
    323 	ip_id = time_uptime & 0xfffff;
    324 
    325 #ifdef GATEWAY
    326 	ipflow_init();
    327 #endif
    328 
    329 	/* Register our Packet Filter hook. */
    330 	inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET);
    331 	KASSERT(inet_pfil_hook != NULL);
    332 
    333 #ifdef MBUFTRACE
    334 	MOWNER_ATTACH(&ip_tx_mowner);
    335 	MOWNER_ATTACH(&ip_rx_mowner);
    336 #endif /* MBUFTRACE */
    337 
    338 	ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
    339 	ipforward_rt_percpu = percpu_alloc(sizeof(struct route));
    340 	ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout);
    341 }
    342 
    343 static struct in_ifaddr *
    344 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch)
    345 {
    346 	struct in_ifaddr *ia = NULL;
    347 	int checkif;
    348 
    349 	/*
    350 	 * Enable a consistency check between the destination address
    351 	 * and the arrival interface for a unicast packet (the RFC 1122
    352 	 * strong ES model) if IP forwarding is disabled and the packet
    353 	 * is not locally generated.
    354 	 *
    355 	 * XXX - Checking also should be disabled if the destination
    356 	 * address is ipnat'ed to a different interface.
    357 	 *
    358 	 * XXX - Checking is incompatible with IP aliases added
    359 	 * to the loopback interface instead of the interface where
    360 	 * the packets are received.
    361 	 *
    362 	 * XXX - We need to add a per ifaddr flag for this so that
    363 	 * we get finer grain control.
    364 	 */
    365 	checkif = ip_checkinterface && (ipforwarding == 0) &&
    366 	    (ifp->if_flags & IFF_LOOPBACK) == 0;
    367 
    368 	IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) {
    369 		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
    370 			if (ia->ia4_flags & IN_IFF_NOTREADY)
    371 				continue;
    372 			if (checkif && ia->ia_ifp != ifp)
    373 				continue;
    374 			if ((ia->ia_ifp->if_flags & IFF_UP) != 0 &&
    375 			    (ia->ia4_flags & IN_IFF_DETACHED) == 0)
    376 				break;
    377 			else
    378 				(*downmatch)++;
    379 		}
    380 	}
    381 
    382 	return ia;
    383 }
    384 
    385 static struct in_ifaddr *
    386 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip)
    387 {
    388 	struct in_ifaddr *ia = NULL;
    389 	struct ifaddr *ifa;
    390 
    391 	IFADDR_READER_FOREACH(ifa, ifp) {
    392 		if (ifa->ifa_addr->sa_family != AF_INET)
    393 			continue;
    394 		ia = ifatoia(ifa);
    395 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
    396 			continue;
    397 		if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
    398 		    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
    399 		    /*
    400 		     * Look for all-0's host part (old broadcast addr),
    401 		     * either for subnet or net.
    402 		     */
    403 		    ip->ip_dst.s_addr == ia->ia_subnet ||
    404 		    ip->ip_dst.s_addr == ia->ia_net)
    405 			goto matched;
    406 		/*
    407 		 * An interface with IP address zero accepts
    408 		 * all packets that arrive on that interface.
    409 		 */
    410 		if (in_nullhost(ia->ia_addr.sin_addr))
    411 			goto matched;
    412 	}
    413 	ia = NULL;
    414 
    415 matched:
    416 	return ia;
    417 }
    418 
    419 /*
    420  * IP software interrupt routine.
    421  */
    422 static void
    423 ipintr(void *arg __unused)
    424 {
    425 	struct mbuf *m;
    426 
    427 	KASSERT(cpu_softintr_p());
    428 
    429 #ifndef NET_MPSAFE
    430 	mutex_enter(softnet_lock);
    431 #endif
    432 	while ((m = pktq_dequeue(ip_pktq)) != NULL) {
    433 		ip_input(m);
    434 	}
    435 #ifndef NET_MPSAFE
    436 	mutex_exit(softnet_lock);
    437 #endif
    438 }
    439 
    440 /*
    441  * IP input routine.  Checksum and byte swap header.  If fragmented
    442  * try to reassemble.  Process options.  Pass to next level.
    443  */
    444 static void
    445 ip_input(struct mbuf *m)
    446 {
    447 	struct ip *ip = NULL;
    448 	struct in_ifaddr *ia = NULL;
    449 	int hlen = 0, len;
    450 	int downmatch;
    451 	int srcrt = 0;
    452 	ifnet_t *ifp;
    453 	struct psref psref;
    454 	int s;
    455 
    456 	KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software "
    457 	    "interrupt handler; synchronization assumptions violated");
    458 
    459 	MCLAIM(m, &ip_rx_mowner);
    460 	KASSERT((m->m_flags & M_PKTHDR) != 0);
    461 
    462 	ifp = m_get_rcvif_psref(m, &psref);
    463 	if (__predict_false(ifp == NULL))
    464 		goto out;
    465 
    466 	/*
    467 	 * If no IP addresses have been set yet but the interfaces
    468 	 * are receiving, can't do anything with incoming packets yet.
    469 	 * Note: we pre-check without locks held.
    470 	 */
    471 	if (IN_ADDRLIST_READER_EMPTY())
    472 		goto out;
    473 	IP_STATINC(IP_STAT_TOTAL);
    474 
    475 	/*
    476 	 * If the IP header is not aligned, slurp it up into a new
    477 	 * mbuf with space for link headers, in the event we forward
    478 	 * it.  Otherwise, if it is aligned, make sure the entire
    479 	 * base IP header is in the first mbuf of the chain.
    480 	 */
    481 	if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
    482 		if ((m = m_copyup(m, sizeof(struct ip),
    483 				  (max_linkhdr + 3) & ~3)) == NULL) {
    484 			/* XXXJRT new stat, please */
    485 			IP_STATINC(IP_STAT_TOOSMALL);
    486 			goto out;
    487 		}
    488 	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
    489 		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
    490 			IP_STATINC(IP_STAT_TOOSMALL);
    491 			goto out;
    492 		}
    493 	}
    494 	ip = mtod(m, struct ip *);
    495 	if (ip->ip_v != IPVERSION) {
    496 		IP_STATINC(IP_STAT_BADVERS);
    497 		goto out;
    498 	}
    499 	hlen = ip->ip_hl << 2;
    500 	if (hlen < sizeof(struct ip)) {	/* minimum header length */
    501 		IP_STATINC(IP_STAT_BADHLEN);
    502 		goto out;
    503 	}
    504 	if (hlen > m->m_len) {
    505 		if ((m = m_pullup(m, hlen)) == NULL) {
    506 			IP_STATINC(IP_STAT_BADHLEN);
    507 			goto out;
    508 		}
    509 		ip = mtod(m, struct ip *);
    510 	}
    511 
    512 	/*
    513 	 * RFC1122: packets with a multicast source address are
    514 	 * not allowed.
    515 	 */
    516 	if (IN_MULTICAST(ip->ip_src.s_addr)) {
    517 		IP_STATINC(IP_STAT_BADADDR);
    518 		goto out;
    519 	}
    520 
    521 	/* 127/8 must not appear on wire - RFC1122 */
    522 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
    523 	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
    524 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
    525 			IP_STATINC(IP_STAT_BADADDR);
    526 			goto out;
    527 		}
    528 	}
    529 
    530 	switch (m->m_pkthdr.csum_flags &
    531 		((ifp->if_csum_flags_rx & M_CSUM_IPv4) |
    532 		 M_CSUM_IPv4_BAD)) {
    533 	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
    534 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
    535 		IP_STATINC(IP_STAT_BADSUM);
    536 		goto out;
    537 
    538 	case M_CSUM_IPv4:
    539 		/* Checksum was okay. */
    540 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
    541 		break;
    542 
    543 	default:
    544 		/*
    545 		 * Must compute it ourselves.  Maybe skip checksum on
    546 		 * loopback interfaces.
    547 		 */
    548 		if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) ||
    549 		    ip_do_loopback_cksum)) {
    550 			INET_CSUM_COUNTER_INCR(&ip_swcsum);
    551 			if (in_cksum(m, hlen) != 0) {
    552 				IP_STATINC(IP_STAT_BADSUM);
    553 				goto out;
    554 			}
    555 		}
    556 		break;
    557 	}
    558 
    559 	/* Retrieve the packet length. */
    560 	len = ntohs(ip->ip_len);
    561 
    562 	/*
    563 	 * Check for additional length bogosity
    564 	 */
    565 	if (len < hlen) {
    566 		IP_STATINC(IP_STAT_BADLEN);
    567 		goto out;
    568 	}
    569 
    570 	/*
    571 	 * Check that the amount of data in the buffers
    572 	 * is as at least much as the IP header would have us expect.
    573 	 * Trim mbufs if longer than we expect.
    574 	 * Drop packet if shorter than we expect.
    575 	 */
    576 	if (m->m_pkthdr.len < len) {
    577 		IP_STATINC(IP_STAT_TOOSHORT);
    578 		goto out;
    579 	}
    580 	if (m->m_pkthdr.len > len) {
    581 		if (m->m_len == m->m_pkthdr.len) {
    582 			m->m_len = len;
    583 			m->m_pkthdr.len = len;
    584 		} else
    585 			m_adj(m, len - m->m_pkthdr.len);
    586 	}
    587 
    588 	/*
    589 	 * Assume that we can create a fast-forward IP flow entry
    590 	 * based on this packet.
    591 	 */
    592 	m->m_flags |= M_CANFASTFWD;
    593 
    594 	/*
    595 	 * Run through list of hooks for input packets.  If there are any
    596 	 * filters which require that additional packets in the flow are
    597 	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
    598 	 * Note that filters must _never_ set this flag, as another filter
    599 	 * in the list may have previously cleared it.
    600 	 */
    601 #if defined(IPSEC)
    602 	if (!ipsec_used || !ipsec_indone(m))
    603 #else
    604 	if (1)
    605 #endif
    606 	{
    607 		struct in_addr odst = ip->ip_dst;
    608 		bool freed;
    609 
    610 		freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0;
    611 		if (freed || m == NULL) {
    612 			m = NULL;
    613 			goto out;
    614 		}
    615 		ip = mtod(m, struct ip *);
    616 		hlen = ip->ip_hl << 2;
    617 
    618 		/*
    619 		 * XXX The setting of "srcrt" here is to prevent ip_forward()
    620 		 * from generating ICMP redirects for packets that have
    621 		 * been redirected by a hook back out on to the same LAN that
    622 		 * they came from and is not an indication that the packet
    623 		 * is being inffluenced by source routing options.  This
    624 		 * allows things like
    625 		 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
    626 		 * where tlp0 is both on the 1.1.1.0/24 network and is the
    627 		 * default route for hosts on 1.1.1.0/24.  Of course this
    628 		 * also requires a "map tlp0 ..." to complete the story.
    629 		 * One might argue whether or not this kind of network config.
    630 		 * should be supported in this manner...
    631 		 */
    632 		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
    633 	}
    634 
    635 #ifdef ALTQ
    636 	/* XXX Temporary until ALTQ is changed to use a pfil hook */
    637 	if (altq_input) {
    638 		SOFTNET_LOCK();
    639 		if ((*altq_input)(m, AF_INET) == 0) {
    640 			/* Packet dropped by traffic conditioner. */
    641 			SOFTNET_UNLOCK();
    642 			m = NULL;
    643 			goto out;
    644 		}
    645 		SOFTNET_UNLOCK();
    646 	}
    647 #endif
    648 
    649 	/*
    650 	 * Process options and, if not destined for us,
    651 	 * ship it on.  ip_dooptions returns 1 when an
    652 	 * error was detected (causing an icmp message
    653 	 * to be sent and the original packet to be freed).
    654 	 */
    655 	if (hlen > sizeof (struct ip) && ip_dooptions(m)) {
    656 		m = NULL;
    657 		goto out;
    658 	}
    659 
    660 	/*
    661 	 * Check our list of addresses, to see if the packet is for us.
    662 	 *
    663 	 * Traditional 4.4BSD did not consult IFF_UP at all.
    664 	 * The behavior here is to treat addresses on !IFF_UP interface
    665 	 * or IN_IFF_NOTREADY addresses as not mine.
    666 	 */
    667 	downmatch = 0;
    668 	s = pserialize_read_enter();
    669 	ia = ip_match_our_address(ifp, ip, &downmatch);
    670 	if (ia != NULL) {
    671 		pserialize_read_exit(s);
    672 		goto ours;
    673 	}
    674 
    675 	if (ifp->if_flags & IFF_BROADCAST) {
    676 		ia = ip_match_our_address_broadcast(ifp, ip);
    677 		if (ia != NULL) {
    678 			pserialize_read_exit(s);
    679 			goto ours;
    680 		}
    681 	}
    682 	pserialize_read_exit(s);
    683 
    684 	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
    685 #ifdef MROUTING
    686 		extern struct socket *ip_mrouter;
    687 
    688 		if (ip_mrouter) {
    689 			/*
    690 			 * If we are acting as a multicast router, all
    691 			 * incoming multicast packets are passed to the
    692 			 * kernel-level multicast forwarding function.
    693 			 * The packet is returned (relatively) intact; if
    694 			 * ip_mforward() returns a non-zero value, the packet
    695 			 * must be discarded, else it may be accepted below.
    696 			 *
    697 			 * (The IP ident field is put in the same byte order
    698 			 * as expected when ip_mforward() is called from
    699 			 * ip_output().)
    700 			 */
    701 			SOFTNET_LOCK();
    702 			if (ip_mforward(m, ifp) != 0) {
    703 				SOFTNET_UNLOCK();
    704 				IP_STATINC(IP_STAT_CANTFORWARD);
    705 				goto out;
    706 			}
    707 			SOFTNET_UNLOCK();
    708 
    709 			/*
    710 			 * The process-level routing demon needs to receive
    711 			 * all multicast IGMP packets, whether or not this
    712 			 * host belongs to their destination groups.
    713 			 */
    714 			if (ip->ip_p == IPPROTO_IGMP) {
    715 				goto ours;
    716 			}
    717 			IP_STATINC(IP_STAT_CANTFORWARD);
    718 		}
    719 #endif
    720 		/*
    721 		 * See if we belong to the destination multicast group on the
    722 		 * arrival interface.
    723 		 */
    724 		if (!in_multi_group(ip->ip_dst, ifp, 0)) {
    725 			IP_STATINC(IP_STAT_CANTFORWARD);
    726 			goto out;
    727 		}
    728 		goto ours;
    729 	}
    730 	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
    731 	    in_nullhost(ip->ip_dst))
    732 		goto ours;
    733 
    734 	/*
    735 	 * Not for us; forward if possible and desirable.
    736 	 */
    737 	if (ipforwarding == 0) {
    738 		m_put_rcvif_psref(ifp, &psref);
    739 		IP_STATINC(IP_STAT_CANTFORWARD);
    740 		m_freem(m);
    741 	} else {
    742 		/*
    743 		 * If ip_dst matched any of my address on !IFF_UP interface,
    744 		 * and there's no IFF_UP interface that matches ip_dst,
    745 		 * send icmp unreach.  Forwarding it will result in in-kernel
    746 		 * forwarding loop till TTL goes to 0.
    747 		 */
    748 		if (downmatch) {
    749 			m_put_rcvif_psref(ifp, &psref);
    750 			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
    751 			IP_STATINC(IP_STAT_CANTFORWARD);
    752 			return;
    753 		}
    754 #ifdef IPSEC
    755 		/* Check the security policy (SP) for the packet */
    756 		if (ipsec_used) {
    757 			SOFTNET_LOCK();
    758 			if (ipsec4_input(m, IP_FORWARDING |
    759 			    (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) {
    760 				SOFTNET_UNLOCK();
    761 				goto out;
    762 			}
    763 			SOFTNET_UNLOCK();
    764 		}
    765 #endif
    766 		ip_forward(m, srcrt, ifp);
    767 		m_put_rcvif_psref(ifp, &psref);
    768 	}
    769 	return;
    770 
    771 ours:
    772 	m_put_rcvif_psref(ifp, &psref);
    773 	ifp = NULL;
    774 
    775 	/*
    776 	 * If offset or IP_MF are set, must reassemble.
    777 	 */
    778 	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
    779 		/*
    780 		 * Pass to IP reassembly mechanism.
    781 		 */
    782 		if (ip_reass_packet(&m, ip) != 0) {
    783 			/* Failed; invalid fragment(s) or packet. */
    784 			goto out;
    785 		}
    786 		if (m == NULL) {
    787 			/* More fragments should come; silently return. */
    788 			goto out;
    789 		}
    790 		/*
    791 		 * Reassembly is done, we have the final packet.
    792 		 * Updated cached data in local variable(s).
    793 		 */
    794 		ip = mtod(m, struct ip *);
    795 		hlen = ip->ip_hl << 2;
    796 	}
    797 
    798 #ifdef IPSEC
    799 	/*
    800 	 * Enforce IPsec policy checking if we are seeing last header.
    801 	 * Note that we do not visit this with protocols with PCB layer
    802 	 * code - like UDP/TCP/raw IP.
    803 	 */
    804 	if (ipsec_used &&
    805 	    (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
    806 		SOFTNET_LOCK();
    807 		if (ipsec4_input(m, 0) != 0) {
    808 			SOFTNET_UNLOCK();
    809 			goto out;
    810 		}
    811 		SOFTNET_UNLOCK();
    812 	}
    813 #endif
    814 
    815 	/*
    816 	 * Switch out to protocol's input routine.
    817 	 */
    818 #if IFA_STATS
    819 	if (ia && ip) {
    820 		struct in_ifaddr *_ia;
    821 		/*
    822 		 * Keep a reference from ip_match_our_address with psref
    823 		 * is expensive, so explore ia here again.
    824 		 */
    825 		s = pserialize_read_enter();
    826 		_ia = in_get_ia(ip->ip_dst);
    827 		_ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
    828 		pserialize_read_exit(s);
    829 	}
    830 #endif
    831 	IP_STATINC(IP_STAT_DELIVERED);
    832 
    833 	const int off = hlen, nh = ip->ip_p;
    834 
    835 	SOFTNET_LOCK();
    836 	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
    837 	SOFTNET_UNLOCK();
    838 	return;
    839 
    840 out:
    841 	m_put_rcvif_psref(ifp, &psref);
    842 	if (m != NULL)
    843 		m_freem(m);
    844 }
    845 
    846 /*
    847  * IP timer processing.
    848  */
    849 void
    850 ip_slowtimo(void)
    851 {
    852 
    853 #ifndef NET_MPSAFE
    854 	mutex_enter(softnet_lock);
    855 	KERNEL_LOCK(1, NULL);
    856 #endif
    857 
    858 	ip_reass_slowtimo();
    859 
    860 #ifndef NET_MPSAFE
    861 	KERNEL_UNLOCK_ONE(NULL);
    862 	mutex_exit(softnet_lock);
    863 #endif
    864 }
    865 
    866 /*
    867  * IP drain processing.
    868  */
    869 void
    870 ip_drain(void)
    871 {
    872 
    873 	KERNEL_LOCK(1, NULL);
    874 	ip_reass_drain();
    875 	KERNEL_UNLOCK_ONE(NULL);
    876 }
    877 
    878 /*
    879  * ip_dooptions: perform option processing on a datagram, possibly discarding
    880  * it if bad options are encountered, or forwarding it if source-routed.
    881  *
    882  * => Returns true if packet has been forwarded/freed.
    883  * => Returns false if the packet should be processed further.
    884  */
    885 static bool
    886 ip_dooptions(struct mbuf *m)
    887 {
    888 	struct ip *ip = mtod(m, struct ip *);
    889 	u_char *cp, *cp0;
    890 	struct ip_timestamp *ipt;
    891 	struct in_ifaddr *ia;
    892 	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
    893 	struct in_addr dst;
    894 	n_time ntime;
    895 	struct ifaddr *ifa = NULL;
    896 	int s;
    897 
    898 	dst = ip->ip_dst;
    899 	cp = (u_char *)(ip + 1);
    900 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
    901 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
    902 		opt = cp[IPOPT_OPTVAL];
    903 		if (opt == IPOPT_EOL)
    904 			break;
    905 		if (opt == IPOPT_NOP)
    906 			optlen = 1;
    907 		else {
    908 			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
    909 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    910 				goto bad;
    911 			}
    912 			optlen = cp[IPOPT_OLEN];
    913 			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
    914 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    915 				goto bad;
    916 			}
    917 		}
    918 		switch (opt) {
    919 
    920 		default:
    921 			break;
    922 
    923 		/*
    924 		 * Source routing with record.
    925 		 * Find interface with current destination address.
    926 		 * If none on this machine then drop if strictly routed,
    927 		 * or do nothing if loosely routed.
    928 		 * Record interface address and bring up next address
    929 		 * component.  If strictly routed make sure next
    930 		 * address is on directly accessible net.
    931 		 */
    932 		case IPOPT_LSRR:
    933 		case IPOPT_SSRR: {
    934 			struct psref psref;
    935 			struct sockaddr_in ipaddr = {
    936 			    .sin_len = sizeof(ipaddr),
    937 			    .sin_family = AF_INET,
    938 			};
    939 
    940 			if (ip_allowsrcrt == 0) {
    941 				type = ICMP_UNREACH;
    942 				code = ICMP_UNREACH_NET_PROHIB;
    943 				goto bad;
    944 			}
    945 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
    946 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    947 				goto bad;
    948 			}
    949 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
    950 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
    951 				goto bad;
    952 			}
    953 			ipaddr.sin_addr = ip->ip_dst;
    954 
    955 			s = pserialize_read_enter();
    956 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
    957 			if (ifa == NULL) {
    958 				pserialize_read_exit(s);
    959 				if (opt == IPOPT_SSRR) {
    960 					type = ICMP_UNREACH;
    961 					code = ICMP_UNREACH_SRCFAIL;
    962 					goto bad;
    963 				}
    964 				/*
    965 				 * Loose routing, and not at next destination
    966 				 * yet; nothing to do except forward.
    967 				 */
    968 				break;
    969 			}
    970 			pserialize_read_exit(s);
    971 
    972 			off--;			/* 0 origin */
    973 			if ((off + sizeof(struct in_addr)) > optlen) {
    974 				/*
    975 				 * End of source route.  Should be for us.
    976 				 */
    977 				save_rte(m, cp, ip->ip_src);
    978 				break;
    979 			}
    980 			/*
    981 			 * locate outgoing interface
    982 			 */
    983 			memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
    984 			    sizeof(ipaddr.sin_addr));
    985 			if (opt == IPOPT_SSRR) {
    986 				ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr),
    987 				    &psref);
    988 				if (ifa != NULL)
    989 					ia = ifatoia(ifa);
    990 				else
    991 					ia = NULL;
    992 			} else {
    993 				ia = ip_rtaddr(ipaddr.sin_addr, &psref);
    994 			}
    995 			if (ia == NULL) {
    996 				type = ICMP_UNREACH;
    997 				code = ICMP_UNREACH_SRCFAIL;
    998 				goto bad;
    999 			}
   1000 			ip->ip_dst = ipaddr.sin_addr;
   1001 			bcopy((void *)&ia->ia_addr.sin_addr,
   1002 			    (void *)(cp + off), sizeof(struct in_addr));
   1003 			ia4_release(ia, &psref);
   1004 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1005 			/*
   1006 			 * Let ip_intr's mcast routing check handle mcast pkts
   1007 			 */
   1008 			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
   1009 			break;
   1010 		    }
   1011 
   1012 		case IPOPT_RR: {
   1013 			struct psref psref;
   1014 			struct sockaddr_in ipaddr = {
   1015 			    .sin_len = sizeof(ipaddr),
   1016 			    .sin_family = AF_INET,
   1017 			};
   1018 
   1019 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
   1020 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
   1021 				goto bad;
   1022 			}
   1023 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
   1024 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
   1025 				goto bad;
   1026 			}
   1027 			/*
   1028 			 * If no space remains, ignore.
   1029 			 */
   1030 			off--;			/* 0 origin */
   1031 			if ((off + sizeof(struct in_addr)) > optlen)
   1032 				break;
   1033 			memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
   1034 			    sizeof(ipaddr.sin_addr));
   1035 			/*
   1036 			 * locate outgoing interface; if we're the destination,
   1037 			 * use the incoming interface (should be same).
   1038 			 */
   1039 			ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref);
   1040 			if (ifa == NULL) {
   1041 				ia = ip_rtaddr(ipaddr.sin_addr, &psref);
   1042 				if (ia == NULL) {
   1043 					type = ICMP_UNREACH;
   1044 					code = ICMP_UNREACH_HOST;
   1045 					goto bad;
   1046 				}
   1047 			} else {
   1048 				ia = ifatoia(ifa);
   1049 			}
   1050 			bcopy((void *)&ia->ia_addr.sin_addr,
   1051 			    (void *)(cp + off), sizeof(struct in_addr));
   1052 			ia4_release(ia, &psref);
   1053 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1054 			break;
   1055 		    }
   1056 
   1057 		case IPOPT_TS:
   1058 			code = cp - (u_char *)ip;
   1059 			ipt = (struct ip_timestamp *)cp;
   1060 			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
   1061 				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
   1062 				goto bad;
   1063 			}
   1064 			if (ipt->ipt_ptr < 5) {
   1065 				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
   1066 				goto bad;
   1067 			}
   1068 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
   1069 				if (++ipt->ipt_oflw == 0) {
   1070 					code = (u_char *)&ipt->ipt_ptr -
   1071 					    (u_char *)ip;
   1072 					goto bad;
   1073 				}
   1074 				break;
   1075 			}
   1076 			cp0 = (cp + ipt->ipt_ptr - 1);
   1077 			switch (ipt->ipt_flg) {
   1078 
   1079 			case IPOPT_TS_TSONLY:
   1080 				break;
   1081 
   1082 			case IPOPT_TS_TSANDADDR: {
   1083 				struct ifnet *rcvif;
   1084 				int _s, _ss;
   1085 				struct sockaddr_in ipaddr = {
   1086 				    .sin_len = sizeof(ipaddr),
   1087 				    .sin_family = AF_INET,
   1088 				};
   1089 
   1090 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1091 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1092 					code = (u_char *)&ipt->ipt_ptr -
   1093 					    (u_char *)ip;
   1094 					goto bad;
   1095 				}
   1096 				ipaddr.sin_addr = dst;
   1097 				_ss = pserialize_read_enter();
   1098 				rcvif = m_get_rcvif(m, &_s);
   1099 				if (__predict_true(rcvif != NULL)) {
   1100 					ifa = ifaof_ifpforaddr(sintosa(&ipaddr),
   1101 					    rcvif);
   1102 				}
   1103 				m_put_rcvif(rcvif, &_s);
   1104 				if (ifa == NULL) {
   1105 					pserialize_read_exit(_ss);
   1106 					break;
   1107 				}
   1108 				ia = ifatoia(ifa);
   1109 				bcopy(&ia->ia_addr.sin_addr,
   1110 				    cp0, sizeof(struct in_addr));
   1111 				pserialize_read_exit(_ss);
   1112 				ipt->ipt_ptr += sizeof(struct in_addr);
   1113 				break;
   1114 			}
   1115 
   1116 			case IPOPT_TS_PRESPEC: {
   1117 				struct sockaddr_in ipaddr = {
   1118 				    .sin_len = sizeof(ipaddr),
   1119 				    .sin_family = AF_INET,
   1120 				};
   1121 
   1122 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1123 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1124 					code = (u_char *)&ipt->ipt_ptr -
   1125 					    (u_char *)ip;
   1126 					goto bad;
   1127 				}
   1128 				memcpy(&ipaddr.sin_addr, cp0,
   1129 				    sizeof(struct in_addr));
   1130 				s = pserialize_read_enter();
   1131 				ifa = ifa_ifwithaddr(sintosa(&ipaddr));
   1132 				if (ifa == NULL) {
   1133 					pserialize_read_exit(s);
   1134 					continue;
   1135 				}
   1136 				pserialize_read_exit(s);
   1137 				ipt->ipt_ptr += sizeof(struct in_addr);
   1138 				break;
   1139 			    }
   1140 
   1141 			default:
   1142 				/* XXX can't take &ipt->ipt_flg */
   1143 				code = (u_char *)&ipt->ipt_ptr -
   1144 				    (u_char *)ip + 1;
   1145 				goto bad;
   1146 			}
   1147 			ntime = iptime();
   1148 			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
   1149 			memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
   1150 			    sizeof(n_time));
   1151 			ipt->ipt_ptr += sizeof(n_time);
   1152 		}
   1153 	}
   1154 	if (forward) {
   1155 		struct ifnet *rcvif;
   1156 		struct psref _psref;
   1157 
   1158 		if (ip_forwsrcrt == 0) {
   1159 			type = ICMP_UNREACH;
   1160 			code = ICMP_UNREACH_SRCFAIL;
   1161 			goto bad;
   1162 		}
   1163 
   1164 		rcvif = m_get_rcvif_psref(m, &_psref);
   1165 		if (__predict_false(rcvif == NULL)) {
   1166 			type = ICMP_UNREACH;
   1167 			code = ICMP_UNREACH_HOST;
   1168 			goto bad;
   1169 		}
   1170 		ip_forward(m, 1, rcvif);
   1171 		m_put_rcvif_psref(rcvif, &_psref);
   1172 		return true;
   1173 	}
   1174 	return false;
   1175 bad:
   1176 	icmp_error(m, type, code, 0, 0);
   1177 	IP_STATINC(IP_STAT_BADOPTIONS);
   1178 	return true;
   1179 }
   1180 
   1181 /*
   1182  * ip_rtaddr: given address of next destination (final or next hop),
   1183  * return internet address info of interface to be used to get there.
   1184  */
   1185 static struct in_ifaddr *
   1186 ip_rtaddr(struct in_addr dst, struct psref *psref)
   1187 {
   1188 	struct rtentry *rt;
   1189 	union {
   1190 		struct sockaddr		dst;
   1191 		struct sockaddr_in	dst4;
   1192 	} u;
   1193 	struct route *ro;
   1194 
   1195 	sockaddr_in_init(&u.dst4, &dst, 0);
   1196 
   1197 	ro = percpu_getref(ipforward_rt_percpu);
   1198 	rt = rtcache_lookup(ro, &u.dst);
   1199 	if (rt == NULL) {
   1200 		percpu_putref(ipforward_rt_percpu);
   1201 		return NULL;
   1202 	}
   1203 
   1204 	ia4_acquire(ifatoia(rt->rt_ifa), psref);
   1205 	rtcache_unref(rt, ro);
   1206 	percpu_putref(ipforward_rt_percpu);
   1207 
   1208 	return ifatoia(rt->rt_ifa);
   1209 }
   1210 
   1211 /*
   1212  * save_rte: save incoming source route for use in replies, to be picked
   1213  * up later by ip_srcroute if the receiver is interested.
   1214  */
   1215 static void
   1216 save_rte(struct mbuf *m, u_char *option, struct in_addr dst)
   1217 {
   1218 	struct ip_srcrt *isr;
   1219 	struct m_tag *mtag;
   1220 	unsigned olen;
   1221 
   1222 	olen = option[IPOPT_OLEN];
   1223 	if (olen > sizeof(isr->isr_hdr) + sizeof(isr->isr_routes))
   1224 		return;
   1225 
   1226 	mtag = m_tag_get(PACKET_TAG_SRCROUTE, sizeof(*isr), M_NOWAIT);
   1227 	if (mtag == NULL)
   1228 		return;
   1229 	isr = (struct ip_srcrt *)(mtag + 1);
   1230 
   1231 	memcpy(isr->isr_hdr, option, olen);
   1232 	isr->isr_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
   1233 	isr->isr_dst = dst;
   1234 	m_tag_prepend(m, mtag);
   1235 }
   1236 
   1237 /*
   1238  * Retrieve incoming source route for use in replies,
   1239  * in the same form used by setsockopt.
   1240  * The first hop is placed before the options, will be removed later.
   1241  */
   1242 struct mbuf *
   1243 ip_srcroute(struct mbuf *m0)
   1244 {
   1245 	struct in_addr *p, *q;
   1246 	struct mbuf *m;
   1247 	struct ip_srcrt *isr;
   1248 	struct m_tag *mtag;
   1249 
   1250 	mtag = m_tag_find(m0, PACKET_TAG_SRCROUTE, NULL);
   1251 	if (mtag == NULL)
   1252 		return NULL;
   1253 	isr = (struct ip_srcrt *)(mtag + 1);
   1254 
   1255 	if (isr->isr_nhops == 0)
   1256 		return NULL;
   1257 
   1258 	m = m_get(M_DONTWAIT, MT_SOOPTS);
   1259 	if (m == NULL)
   1260 		return NULL;
   1261 
   1262 	MCLAIM(m, &inetdomain.dom_mowner);
   1263 #define OPTSIZ	(sizeof(isr->isr_nop) + sizeof(isr->isr_hdr))
   1264 
   1265 	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + header) */
   1266 	m->m_len = (isr->isr_nhops + 1) * sizeof(struct in_addr) + OPTSIZ;
   1267 
   1268 	/*
   1269 	 * First save first hop for return route
   1270 	 */
   1271 	p = &(isr->isr_routes[isr->isr_nhops - 1]);
   1272 	*(mtod(m, struct in_addr *)) = *p--;
   1273 
   1274 	/*
   1275 	 * Copy option fields and padding (nop) to mbuf.
   1276 	 */
   1277 	isr->isr_nop = IPOPT_NOP;
   1278 	isr->isr_hdr[IPOPT_OFFSET] = IPOPT_MINOFF;
   1279 	memmove(mtod(m, char *) + sizeof(struct in_addr), &isr->isr_nop,
   1280 	    OPTSIZ);
   1281 	q = (struct in_addr *)(mtod(m, char *) +
   1282 	    sizeof(struct in_addr) + OPTSIZ);
   1283 #undef OPTSIZ
   1284 	/*
   1285 	 * Record return path as an IP source route,
   1286 	 * reversing the path (pointers are now aligned).
   1287 	 */
   1288 	while (p >= isr->isr_routes) {
   1289 		*q++ = *p--;
   1290 	}
   1291 	/*
   1292 	 * Last hop goes to final destination.
   1293 	 */
   1294 	*q = isr->isr_dst;
   1295 	m_tag_delete(m0, mtag);
   1296 	return m;
   1297 }
   1298 
   1299 const int inetctlerrmap[PRC_NCMDS] = {
   1300 	[PRC_MSGSIZE] = EMSGSIZE,
   1301 	[PRC_HOSTDEAD] = EHOSTDOWN,
   1302 	[PRC_HOSTUNREACH] = EHOSTUNREACH,
   1303 	[PRC_UNREACH_NET] = EHOSTUNREACH,
   1304 	[PRC_UNREACH_HOST] = EHOSTUNREACH,
   1305 	[PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
   1306 	[PRC_UNREACH_PORT] = ECONNREFUSED,
   1307 	[PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
   1308 	[PRC_PARAMPROB] = ENOPROTOOPT,
   1309 };
   1310 
   1311 void
   1312 ip_fasttimo(void)
   1313 {
   1314 	if (ip_drainwanted) {
   1315 		ip_drain();
   1316 		ip_drainwanted = 0;
   1317 	}
   1318 }
   1319 
   1320 void
   1321 ip_drainstub(void)
   1322 {
   1323 	ip_drainwanted = 1;
   1324 }
   1325 
   1326 /*
   1327  * Forward a packet.  If some error occurs return the sender
   1328  * an icmp packet.  Note we can't always generate a meaningful
   1329  * icmp message because icmp doesn't have a large enough repertoire
   1330  * of codes and types.
   1331  *
   1332  * If not forwarding, just drop the packet.  This could be confusing
   1333  * if ipforwarding was zero but some routing protocol was advancing
   1334  * us as a gateway to somewhere.  However, we must let the routing
   1335  * protocol deal with that.
   1336  *
   1337  * The srcrt parameter indicates whether the packet is being forwarded
   1338  * via a source route.
   1339  */
   1340 static void
   1341 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif)
   1342 {
   1343 	struct ip *ip = mtod(m, struct ip *);
   1344 	struct rtentry *rt;
   1345 	int error, type = 0, code = 0, destmtu = 0;
   1346 	struct mbuf *mcopy;
   1347 	n_long dest;
   1348 	union {
   1349 		struct sockaddr		dst;
   1350 		struct sockaddr_in	dst4;
   1351 	} u;
   1352 	uint64_t *ips;
   1353 	struct route *ro;
   1354 
   1355 	KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software "
   1356 	    "interrupt handler; synchronization assumptions violated");
   1357 
   1358 	/*
   1359 	 * We are now in the output path.
   1360 	 */
   1361 	MCLAIM(m, &ip_tx_mowner);
   1362 
   1363 	/*
   1364 	 * Clear any in-bound checksum flags for this packet.
   1365 	 */
   1366 	m->m_pkthdr.csum_flags = 0;
   1367 
   1368 	dest = 0;
   1369 	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
   1370 		IP_STATINC(IP_STAT_CANTFORWARD);
   1371 		m_freem(m);
   1372 		return;
   1373 	}
   1374 
   1375 	if (ip->ip_ttl <= IPTTLDEC) {
   1376 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
   1377 		return;
   1378 	}
   1379 
   1380 	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
   1381 
   1382 	ro = percpu_getref(ipforward_rt_percpu);
   1383 	rt = rtcache_lookup(ro, &u.dst);
   1384 	if (rt == NULL) {
   1385 		percpu_putref(ipforward_rt_percpu);
   1386 		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
   1387 		return;
   1388 	}
   1389 
   1390 	/*
   1391 	 * Save at most 68 bytes of the packet in case
   1392 	 * we need to generate an ICMP message to the src.
   1393 	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
   1394 	 */
   1395 	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
   1396 	if (mcopy)
   1397 		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
   1398 
   1399 	ip->ip_ttl -= IPTTLDEC;
   1400 
   1401 	/*
   1402 	 * If forwarding packet using same interface that it came in on,
   1403 	 * perhaps should send a redirect to sender to shortcut a hop.
   1404 	 * Only send redirect if source is sending directly to us,
   1405 	 * and if packet was not source routed (or has any options).
   1406 	 * Also, don't send redirect if forwarding using a default route
   1407 	 * or a route modified by a redirect.
   1408 	 */
   1409 	if (rt->rt_ifp == rcvif &&
   1410 	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
   1411 	    !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
   1412 	    ipsendredirects && !srcrt) {
   1413 		if (rt->rt_ifa &&
   1414 		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
   1415 		    ifatoia(rt->rt_ifa)->ia_subnet) {
   1416 			if (rt->rt_flags & RTF_GATEWAY)
   1417 				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
   1418 			else
   1419 				dest = ip->ip_dst.s_addr;
   1420 			/*
   1421 			 * Router requirements says to only send host
   1422 			 * redirects.
   1423 			 */
   1424 			type = ICMP_REDIRECT;
   1425 			code = ICMP_REDIRECT_HOST;
   1426 		}
   1427 	}
   1428 	rtcache_unref(rt, ro);
   1429 
   1430 	error = ip_output(m, NULL, ro,
   1431 	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
   1432 	    NULL, NULL);
   1433 
   1434 	if (error) {
   1435 		IP_STATINC(IP_STAT_CANTFORWARD);
   1436 		goto error;
   1437 	}
   1438 
   1439 	ips = IP_STAT_GETREF();
   1440 	ips[IP_STAT_FORWARD]++;
   1441 
   1442 	if (type) {
   1443 		ips[IP_STAT_REDIRECTSENT]++;
   1444 		IP_STAT_PUTREF();
   1445 		goto redirect;
   1446 	}
   1447 
   1448 	IP_STAT_PUTREF();
   1449 	if (mcopy) {
   1450 #ifdef GATEWAY
   1451 		if (mcopy->m_flags & M_CANFASTFWD)
   1452 			ipflow_create(ro, mcopy);
   1453 #endif
   1454 		m_freem(mcopy);
   1455 	}
   1456 
   1457 	percpu_putref(ipforward_rt_percpu);
   1458 	return;
   1459 
   1460 redirect:
   1461 error:
   1462 	if (mcopy == NULL) {
   1463 		percpu_putref(ipforward_rt_percpu);
   1464 		return;
   1465 	}
   1466 
   1467 	switch (error) {
   1468 
   1469 	case 0:				/* forwarded, but need redirect */
   1470 		/* type, code set above */
   1471 		break;
   1472 
   1473 	case ENETUNREACH:		/* shouldn't happen, checked above */
   1474 	case EHOSTUNREACH:
   1475 	case ENETDOWN:
   1476 	case EHOSTDOWN:
   1477 	default:
   1478 		type = ICMP_UNREACH;
   1479 		code = ICMP_UNREACH_HOST;
   1480 		break;
   1481 
   1482 	case EMSGSIZE:
   1483 		type = ICMP_UNREACH;
   1484 		code = ICMP_UNREACH_NEEDFRAG;
   1485 
   1486 		if ((rt = rtcache_validate(ro)) != NULL) {
   1487 			destmtu = rt->rt_ifp->if_mtu;
   1488 			rtcache_unref(rt, ro);
   1489 		}
   1490 #ifdef IPSEC
   1491 		if (ipsec_used)
   1492 			(void)ipsec4_forward(mcopy, &destmtu);
   1493 #endif
   1494 		IP_STATINC(IP_STAT_CANTFRAG);
   1495 		break;
   1496 
   1497 	case ENOBUFS:
   1498 		/*
   1499 		 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812,
   1500 		 * Requirements for IP Version 4 Routers.  Source quench can
   1501 		 * big problem under DoS attacks or if the underlying
   1502 		 * interface is rate-limited.
   1503 		 */
   1504 		if (mcopy)
   1505 			m_freem(mcopy);
   1506 		percpu_putref(ipforward_rt_percpu);
   1507 		return;
   1508 	}
   1509 	icmp_error(mcopy, type, code, dest, destmtu);
   1510 	percpu_putref(ipforward_rt_percpu);
   1511 }
   1512 
   1513 void
   1514 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
   1515     struct mbuf *m)
   1516 {
   1517 	struct socket *so = inp->inp_socket;
   1518 	int inpflags = inp->inp_flags;
   1519 
   1520 	if (SOOPT_TIMESTAMP(so->so_options))
   1521 		mp = sbsavetimestamp(so->so_options, m, mp);
   1522 
   1523 	if (inpflags & INP_RECVDSTADDR) {
   1524 		*mp = sbcreatecontrol(&ip->ip_dst,
   1525 		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
   1526 		if (*mp)
   1527 			mp = &(*mp)->m_next;
   1528 	}
   1529 
   1530 	if (inpflags & INP_RECVTTL) {
   1531 		*mp = sbcreatecontrol(&ip->ip_ttl,
   1532 		    sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
   1533 		if (*mp)
   1534 			mp = &(*mp)->m_next;
   1535 	}
   1536 
   1537 	struct psref psref;
   1538 	ifnet_t *ifp = m_get_rcvif_psref(m, &psref);
   1539 	if (__predict_false(ifp == NULL)) {
   1540 #ifdef DIAGNOSTIC
   1541 		printf("%s: missing receive interface\n", __func__);
   1542 #endif
   1543 		return; /* XXX should report error? */
   1544 	}
   1545 
   1546 	if (inpflags & INP_RECVPKTINFO) {
   1547 		struct in_pktinfo ipi;
   1548 		ipi.ipi_addr = ip->ip_src;
   1549 		ipi.ipi_ifindex = ifp->if_index;
   1550 		*mp = sbcreatecontrol(&ipi,
   1551 		    sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP);
   1552 		if (*mp)
   1553 			mp = &(*mp)->m_next;
   1554 	}
   1555 	if (inpflags & INP_PKTINFO) {
   1556 		struct in_pktinfo ipi;
   1557 		ipi.ipi_addr = ip->ip_dst;
   1558 		ipi.ipi_ifindex = ifp->if_index;
   1559 		*mp = sbcreatecontrol(&ipi,
   1560 		    sizeof(ipi), IP_PKTINFO, IPPROTO_IP);
   1561 		if (*mp)
   1562 			mp = &(*mp)->m_next;
   1563 	}
   1564 	if (inpflags & INP_RECVIF) {
   1565 		struct sockaddr_dl sdl;
   1566 
   1567 		sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0,
   1568 		    NULL, 0);
   1569 		*mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
   1570 		if (*mp)
   1571 			mp = &(*mp)->m_next;
   1572 	}
   1573 	m_put_rcvif_psref(ifp, &psref);
   1574 }
   1575 
   1576 /*
   1577  * sysctl helper routine for net.inet.ip.forwsrcrt.
   1578  */
   1579 static int
   1580 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
   1581 {
   1582 	int error, tmp;
   1583 	struct sysctlnode node;
   1584 
   1585 	node = *rnode;
   1586 	tmp = ip_forwsrcrt;
   1587 	node.sysctl_data = &tmp;
   1588 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1589 	if (error || newp == NULL)
   1590 		return (error);
   1591 
   1592 	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
   1593 	    0, NULL, NULL, NULL);
   1594 	if (error)
   1595 		return (error);
   1596 
   1597 	ip_forwsrcrt = tmp;
   1598 
   1599 	return (0);
   1600 }
   1601 
   1602 /*
   1603  * sysctl helper routine for net.inet.ip.mtudisctimeout.  checks the
   1604  * range of the new value and tweaks timers if it changes.
   1605  */
   1606 static int
   1607 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
   1608 {
   1609 	int error, tmp;
   1610 	struct sysctlnode node;
   1611 
   1612 	icmp_mtudisc_lock();
   1613 
   1614 	node = *rnode;
   1615 	tmp = ip_mtudisc_timeout;
   1616 	node.sysctl_data = &tmp;
   1617 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1618 	if (error || newp == NULL)
   1619 		goto out;
   1620 	if (tmp < 0) {
   1621 		error = EINVAL;
   1622 		goto out;
   1623 	}
   1624 
   1625 	ip_mtudisc_timeout = tmp;
   1626 	rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
   1627 	error = 0;
   1628 out:
   1629 	icmp_mtudisc_unlock();
   1630 	return error;
   1631 }
   1632 
   1633 static int
   1634 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
   1635 {
   1636 
   1637 	return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
   1638 }
   1639 
   1640 static void
   1641 sysctl_net_inet_ip_setup(struct sysctllog **clog)
   1642 {
   1643 	sysctl_createv(clog, 0, NULL, NULL,
   1644 		       CTLFLAG_PERMANENT,
   1645 		       CTLTYPE_NODE, "inet",
   1646 		       SYSCTL_DESCR("PF_INET related settings"),
   1647 		       NULL, 0, NULL, 0,
   1648 		       CTL_NET, PF_INET, CTL_EOL);
   1649 	sysctl_createv(clog, 0, NULL, NULL,
   1650 		       CTLFLAG_PERMANENT,
   1651 		       CTLTYPE_NODE, "ip",
   1652 		       SYSCTL_DESCR("IPv4 related settings"),
   1653 		       NULL, 0, NULL, 0,
   1654 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
   1655 
   1656 	sysctl_createv(clog, 0, NULL, NULL,
   1657 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1658 		       CTLTYPE_INT, "forwarding",
   1659 		       SYSCTL_DESCR("Enable forwarding of INET datagrams"),
   1660 		       NULL, 0, &ipforwarding, 0,
   1661 		       CTL_NET, PF_INET, IPPROTO_IP,
   1662 		       IPCTL_FORWARDING, CTL_EOL);
   1663 	sysctl_createv(clog, 0, NULL, NULL,
   1664 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1665 		       CTLTYPE_INT, "redirect",
   1666 		       SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
   1667 		       NULL, 0, &ipsendredirects, 0,
   1668 		       CTL_NET, PF_INET, IPPROTO_IP,
   1669 		       IPCTL_SENDREDIRECTS, CTL_EOL);
   1670 	sysctl_createv(clog, 0, NULL, NULL,
   1671 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1672 		       CTLTYPE_INT, "ttl",
   1673 		       SYSCTL_DESCR("Default TTL for an INET datagram"),
   1674 		       NULL, 0, &ip_defttl, 0,
   1675 		       CTL_NET, PF_INET, IPPROTO_IP,
   1676 		       IPCTL_DEFTTL, CTL_EOL);
   1677 #ifdef IPCTL_DEFMTU
   1678 	sysctl_createv(clog, 0, NULL, NULL,
   1679 		       CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
   1680 		       CTLTYPE_INT, "mtu",
   1681 		       SYSCTL_DESCR("Default MTA for an INET route"),
   1682 		       NULL, 0, &ip_mtu, 0,
   1683 		       CTL_NET, PF_INET, IPPROTO_IP,
   1684 		       IPCTL_DEFMTU, CTL_EOL);
   1685 #endif /* IPCTL_DEFMTU */
   1686 	sysctl_createv(clog, 0, NULL, NULL,
   1687 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1688 		       CTLTYPE_INT, "forwsrcrt",
   1689 		       SYSCTL_DESCR("Enable forwarding of source-routed "
   1690 				    "datagrams"),
   1691 		       sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
   1692 		       CTL_NET, PF_INET, IPPROTO_IP,
   1693 		       IPCTL_FORWSRCRT, CTL_EOL);
   1694 	sysctl_createv(clog, 0, NULL, NULL,
   1695 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1696 		       CTLTYPE_INT, "directed-broadcast",
   1697 		       SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
   1698 		       NULL, 0, &ip_directedbcast, 0,
   1699 		       CTL_NET, PF_INET, IPPROTO_IP,
   1700 		       IPCTL_DIRECTEDBCAST, CTL_EOL);
   1701 	sysctl_createv(clog, 0, NULL, NULL,
   1702 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1703 		       CTLTYPE_INT, "allowsrcrt",
   1704 		       SYSCTL_DESCR("Accept source-routed datagrams"),
   1705 		       NULL, 0, &ip_allowsrcrt, 0,
   1706 		       CTL_NET, PF_INET, IPPROTO_IP,
   1707 		       IPCTL_ALLOWSRCRT, CTL_EOL);
   1708 
   1709 	sysctl_createv(clog, 0, NULL, NULL,
   1710 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1711 		       CTLTYPE_INT, "mtudisc",
   1712 		       SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
   1713 		       NULL, 0, &ip_mtudisc, 0,
   1714 		       CTL_NET, PF_INET, IPPROTO_IP,
   1715 		       IPCTL_MTUDISC, CTL_EOL);
   1716 	sysctl_createv(clog, 0, NULL, NULL,
   1717 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1718 		       CTLTYPE_INT, "anonportmin",
   1719 		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
   1720 		       sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
   1721 		       CTL_NET, PF_INET, IPPROTO_IP,
   1722 		       IPCTL_ANONPORTMIN, CTL_EOL);
   1723 	sysctl_createv(clog, 0, NULL, NULL,
   1724 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1725 		       CTLTYPE_INT, "anonportmax",
   1726 		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
   1727 		       sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
   1728 		       CTL_NET, PF_INET, IPPROTO_IP,
   1729 		       IPCTL_ANONPORTMAX, CTL_EOL);
   1730 	sysctl_createv(clog, 0, NULL, NULL,
   1731 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1732 		       CTLTYPE_INT, "mtudisctimeout",
   1733 		       SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
   1734 		       sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0,
   1735 		       CTL_NET, PF_INET, IPPROTO_IP,
   1736 		       IPCTL_MTUDISCTIMEOUT, CTL_EOL);
   1737 #ifndef IPNOPRIVPORTS
   1738 	sysctl_createv(clog, 0, NULL, NULL,
   1739 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1740 		       CTLTYPE_INT, "lowportmin",
   1741 		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
   1742 				    "to assign"),
   1743 		       sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
   1744 		       CTL_NET, PF_INET, IPPROTO_IP,
   1745 		       IPCTL_LOWPORTMIN, CTL_EOL);
   1746 	sysctl_createv(clog, 0, NULL, NULL,
   1747 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1748 		       CTLTYPE_INT, "lowportmax",
   1749 		       SYSCTL_DESCR("Highest privileged ephemeral port number "
   1750 				    "to assign"),
   1751 		       sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
   1752 		       CTL_NET, PF_INET, IPPROTO_IP,
   1753 		       IPCTL_LOWPORTMAX, CTL_EOL);
   1754 #endif /* IPNOPRIVPORTS */
   1755 #if NGRE > 0
   1756 	sysctl_createv(clog, 0, NULL, NULL,
   1757 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1758 		       CTLTYPE_INT, "grettl",
   1759 		       SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
   1760 		       NULL, 0, &ip_gre_ttl, 0,
   1761 		       CTL_NET, PF_INET, IPPROTO_IP,
   1762 		       IPCTL_GRE_TTL, CTL_EOL);
   1763 #endif /* NGRE */
   1764 	sysctl_createv(clog, 0, NULL, NULL,
   1765 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1766 		       CTLTYPE_INT, "checkinterface",
   1767 		       SYSCTL_DESCR("Enable receive side of Strong ES model "
   1768 				    "from RFC1122"),
   1769 		       NULL, 0, &ip_checkinterface, 0,
   1770 		       CTL_NET, PF_INET, IPPROTO_IP,
   1771 		       IPCTL_CHECKINTERFACE, CTL_EOL);
   1772 	sysctl_createv(clog, 0, NULL, NULL,
   1773 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1774 		       CTLTYPE_INT, "random_id",
   1775 		       SYSCTL_DESCR("Assign random ip_id values"),
   1776 		       NULL, 0, &ip_do_randomid, 0,
   1777 		       CTL_NET, PF_INET, IPPROTO_IP,
   1778 		       IPCTL_RANDOMID, CTL_EOL);
   1779 	sysctl_createv(clog, 0, NULL, NULL,
   1780 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1781 		       CTLTYPE_INT, "do_loopback_cksum",
   1782 		       SYSCTL_DESCR("Perform IP checksum on loopback"),
   1783 		       NULL, 0, &ip_do_loopback_cksum, 0,
   1784 		       CTL_NET, PF_INET, IPPROTO_IP,
   1785 		       IPCTL_LOOPBACKCKSUM, CTL_EOL);
   1786 	sysctl_createv(clog, 0, NULL, NULL,
   1787 		       CTLFLAG_PERMANENT,
   1788 		       CTLTYPE_STRUCT, "stats",
   1789 		       SYSCTL_DESCR("IP statistics"),
   1790 		       sysctl_net_inet_ip_stats, 0, NULL, 0,
   1791 		       CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
   1792 		       CTL_EOL);
   1793 #if NARP
   1794 	sysctl_createv(clog, 0, NULL, NULL,
   1795 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1796 		       CTLTYPE_INT, "dad_count",
   1797 		       SYSCTL_DESCR("Number of Duplicate Address Detection "
   1798 				    "probes to send"),
   1799 		       NULL, 0, &ip_dad_count, 0,
   1800 		       CTL_NET, PF_INET, IPPROTO_IP,
   1801 		       IPCTL_DAD_COUNT, CTL_EOL);
   1802 #endif
   1803 
   1804 	/* anonportalgo RFC6056 subtree */
   1805 	const struct sysctlnode *portalgo_node;
   1806 	sysctl_createv(clog, 0, NULL, &portalgo_node,
   1807 		       CTLFLAG_PERMANENT,
   1808 		       CTLTYPE_NODE, "anonportalgo",
   1809 		       SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"),
   1810 	    	       NULL, 0, NULL, 0,
   1811 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL);
   1812 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1813 		       CTLFLAG_PERMANENT,
   1814 		       CTLTYPE_STRING, "available",
   1815 		       SYSCTL_DESCR("available algorithms"),
   1816 		       sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
   1817 		       CTL_CREATE, CTL_EOL);
   1818 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1819 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1820 		       CTLTYPE_STRING, "selected",
   1821 		       SYSCTL_DESCR("selected algorithm"),
   1822 		       sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN,
   1823 		       CTL_CREATE, CTL_EOL);
   1824 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1825 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1826 		       CTLTYPE_STRUCT, "reserve",
   1827 		       SYSCTL_DESCR("bitmap of reserved ports"),
   1828 		       sysctl_portalgo_reserve4, 0, NULL, 0,
   1829 		       CTL_CREATE, CTL_EOL);
   1830 }
   1831 
   1832 void
   1833 ip_statinc(u_int stat)
   1834 {
   1835 
   1836 	KASSERT(stat < IP_NSTATS);
   1837 	IP_STATINC(stat);
   1838 }
   1839