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ip_input.c revision 1.340
      1 /*	$NetBSD: ip_input.c,v 1.340 2016/08/31 09:14:47 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 1.340 2016/08/31 09:14:47 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 #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 #ifdef COMPAT_50
    177 #include <compat/sys/time.h>
    178 #include <compat/sys/socket.h>
    179 #endif
    180 
    181 /*
    182  * Note: DIRECTED_BROADCAST is handled this way so that previous
    183  * configuration using this option will Just Work.
    184  */
    185 #ifndef IPDIRECTEDBCAST
    186 #ifdef DIRECTED_BROADCAST
    187 #define IPDIRECTEDBCAST	1
    188 #else
    189 #define	IPDIRECTEDBCAST	0
    190 #endif /* DIRECTED_BROADCAST */
    191 #endif /* IPDIRECTEDBCAST */
    192 int	ipforwarding = IPFORWARDING;
    193 int	ipsendredirects = IPSENDREDIRECTS;
    194 int	ip_defttl = IPDEFTTL;
    195 int	ip_forwsrcrt = IPFORWSRCRT;
    196 int	ip_directedbcast = IPDIRECTEDBCAST;
    197 int	ip_allowsrcrt = IPALLOWSRCRT;
    198 int	ip_mtudisc = IPMTUDISC;
    199 int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
    200 #ifdef DIAGNOSTIC
    201 int	ipprintfs = 0;
    202 #endif
    203 
    204 int	ip_do_randomid = 0;
    205 
    206 /*
    207  * XXX - Setting ip_checkinterface mostly implements the receive side of
    208  * the Strong ES model described in RFC 1122, but since the routing table
    209  * and transmit implementation do not implement the Strong ES model,
    210  * setting this to 1 results in an odd hybrid.
    211  *
    212  * XXX - ip_checkinterface currently must be disabled if you use ipnat
    213  * to translate the destination address to another local interface.
    214  *
    215  * XXX - ip_checkinterface must be disabled if you add IP aliases
    216  * to the loopback interface instead of the interface where the
    217  * packets for those addresses are received.
    218  */
    219 static int		ip_checkinterface	__read_mostly = 0;
    220 
    221 struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
    222 
    223 pktqueue_t *		ip_pktq			__read_mostly;
    224 pfil_head_t *		inet_pfil_hook		__read_mostly;
    225 ipid_state_t *		ip_ids			__read_mostly;
    226 percpu_t *		ipstat_percpu		__read_mostly;
    227 
    228 static percpu_t		*ipforward_rt_percpu	__cacheline_aligned;
    229 
    230 uint16_t ip_id;
    231 
    232 #ifdef INET_CSUM_COUNTERS
    233 #include <sys/device.h>
    234 
    235 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    236     NULL, "inet", "hwcsum bad");
    237 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    238     NULL, "inet", "hwcsum ok");
    239 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
    240     NULL, "inet", "swcsum");
    241 
    242 #define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
    243 
    244 EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
    245 EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
    246 EVCNT_ATTACH_STATIC(ip_swcsum);
    247 
    248 #else
    249 
    250 #define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
    251 
    252 #endif /* INET_CSUM_COUNTERS */
    253 
    254 /*
    255  * We need to save the IP options in case a protocol wants to respond
    256  * to an incoming packet over the same route if the packet got here
    257  * using IP source routing.  This allows connection establishment and
    258  * maintenance when the remote end is on a network that is not known
    259  * to us.
    260  */
    261 
    262 static int	ip_nhops = 0;
    263 
    264 static	struct ip_srcrt {
    265 	struct	in_addr dst;			/* final destination */
    266 	char	nop;				/* one NOP to align */
    267 	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
    268 	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
    269 } ip_srcrt;
    270 
    271 static int ip_drainwanted;
    272 
    273 struct	sockaddr_in ipaddr = {
    274 	.sin_len = sizeof(ipaddr),
    275 	.sin_family = AF_INET,
    276 };
    277 
    278 static void save_rte(u_char *, struct in_addr);
    279 
    280 #ifdef MBUFTRACE
    281 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
    282 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
    283 #endif
    284 
    285 static void		ipintr(void *);
    286 static void		ip_input(struct mbuf *);
    287 static void		ip_forward(struct mbuf *, int, struct ifnet *);
    288 static bool		ip_dooptions(struct mbuf *);
    289 static struct in_ifaddr *ip_rtaddr(struct in_addr);
    290 static void		sysctl_net_inet_ip_setup(struct sysctllog **);
    291 
    292 static struct in_ifaddr	*ip_match_our_address(struct ifnet *, struct ip *,
    293 			    int *);
    294 static struct in_ifaddr	*ip_match_our_address_broadcast(struct ifnet *,
    295 			    struct ip *);
    296 
    297 /* XXX: Not yet enabled. */
    298 #define	SOFTNET_LOCK()		KASSERT(mutex_owned(softnet_lock))
    299 #define	SOFTNET_UNLOCK()	KASSERT(mutex_owned(softnet_lock))
    300 
    301 /*
    302  * IP initialization: fill in IP protocol switch table.
    303  * All protocols not implemented in kernel go to raw IP protocol handler.
    304  */
    305 void
    306 ip_init(void)
    307 {
    308 	const struct protosw *pr;
    309 
    310 	in_init();
    311 	sysctl_net_inet_ip_setup(NULL);
    312 
    313 	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
    314 	KASSERT(pr != NULL);
    315 
    316 	ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL);
    317 	KASSERT(ip_pktq != NULL);
    318 
    319 	for (u_int i = 0; i < IPPROTO_MAX; i++) {
    320 		ip_protox[i] = pr - inetsw;
    321 	}
    322 	for (pr = inetdomain.dom_protosw;
    323 	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
    324 		if (pr->pr_domain->dom_family == PF_INET &&
    325 		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
    326 			ip_protox[pr->pr_protocol] = pr - inetsw;
    327 
    328 	ip_reass_init();
    329 
    330 	ip_ids = ip_id_init();
    331 	ip_id = time_uptime & 0xfffff;
    332 
    333 	ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout);
    334 #ifdef GATEWAY
    335 	ipflow_init();
    336 #endif
    337 
    338 	/* Register our Packet Filter hook. */
    339 	inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET);
    340 	KASSERT(inet_pfil_hook != NULL);
    341 
    342 #ifdef MBUFTRACE
    343 	MOWNER_ATTACH(&ip_tx_mowner);
    344 	MOWNER_ATTACH(&ip_rx_mowner);
    345 #endif /* MBUFTRACE */
    346 
    347 	ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
    348 
    349 	ipforward_rt_percpu = percpu_alloc(sizeof(struct route));
    350 	if (ipforward_rt_percpu == NULL)
    351 		panic("failed to allocate ipforward_rt_percpu");
    352 }
    353 
    354 static struct in_ifaddr *
    355 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch)
    356 {
    357 	struct in_ifaddr *ia = NULL;
    358 	int checkif;
    359 
    360 	/*
    361 	 * Enable a consistency check between the destination address
    362 	 * and the arrival interface for a unicast packet (the RFC 1122
    363 	 * strong ES model) if IP forwarding is disabled and the packet
    364 	 * is not locally generated.
    365 	 *
    366 	 * XXX - Checking also should be disabled if the destination
    367 	 * address is ipnat'ed to a different interface.
    368 	 *
    369 	 * XXX - Checking is incompatible with IP aliases added
    370 	 * to the loopback interface instead of the interface where
    371 	 * the packets are received.
    372 	 *
    373 	 * XXX - We need to add a per ifaddr flag for this so that
    374 	 * we get finer grain control.
    375 	 */
    376 	checkif = ip_checkinterface && (ipforwarding == 0) &&
    377 	    (ifp->if_flags & IFF_LOOPBACK) == 0;
    378 
    379 	IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) {
    380 		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
    381 			if (ia->ia4_flags & IN_IFF_NOTREADY)
    382 				continue;
    383 			if (checkif && ia->ia_ifp != ifp)
    384 				continue;
    385 			if ((ia->ia_ifp->if_flags & IFF_UP) != 0)
    386 				break;
    387 			else
    388 				(*downmatch)++;
    389 		}
    390 	}
    391 
    392 	return ia;
    393 }
    394 
    395 static struct in_ifaddr *
    396 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip)
    397 {
    398 	struct in_ifaddr *ia = NULL;
    399 	struct ifaddr *ifa;
    400 
    401 	IFADDR_READER_FOREACH(ifa, ifp) {
    402 		if (ifa->ifa_addr->sa_family != AF_INET)
    403 			continue;
    404 		ia = ifatoia(ifa);
    405 		if (ia->ia4_flags & IN_IFF_NOTREADY)
    406 			continue;
    407 		if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
    408 		    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
    409 		    /*
    410 		     * Look for all-0's host part (old broadcast addr),
    411 		     * either for subnet or net.
    412 		     */
    413 		    ip->ip_dst.s_addr == ia->ia_subnet ||
    414 		    ip->ip_dst.s_addr == ia->ia_net)
    415 			goto matched;
    416 		/*
    417 		 * An interface with IP address zero accepts
    418 		 * all packets that arrive on that interface.
    419 		 */
    420 		if (in_nullhost(ia->ia_addr.sin_addr))
    421 			goto matched;
    422 	}
    423 	ia = NULL;
    424 
    425 matched:
    426 	return ia;
    427 }
    428 
    429 /*
    430  * IP software interrupt routine.
    431  */
    432 static void
    433 ipintr(void *arg __unused)
    434 {
    435 	struct mbuf *m;
    436 
    437 	KASSERT(cpu_softintr_p());
    438 
    439 	mutex_enter(softnet_lock);
    440 	while ((m = pktq_dequeue(ip_pktq)) != NULL) {
    441 		ip_input(m);
    442 	}
    443 	mutex_exit(softnet_lock);
    444 }
    445 
    446 /*
    447  * IP input routine.  Checksum and byte swap header.  If fragmented
    448  * try to reassemble.  Process options.  Pass to next level.
    449  */
    450 static void
    451 ip_input(struct mbuf *m)
    452 {
    453 	struct ip *ip = NULL;
    454 	struct in_ifaddr *ia = NULL;
    455 	int hlen = 0, len;
    456 	int downmatch;
    457 	int srcrt = 0;
    458 	ifnet_t *ifp;
    459 	struct psref psref;
    460 	int s;
    461 
    462 	KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software "
    463 	    "interrupt handler; synchronization assumptions violated");
    464 
    465 	MCLAIM(m, &ip_rx_mowner);
    466 	KASSERT((m->m_flags & M_PKTHDR) != 0);
    467 
    468 	ifp = m_get_rcvif_psref(m, &psref);
    469 	if (__predict_false(ifp == NULL))
    470 		goto out;
    471 
    472 	/*
    473 	 * If no IP addresses have been set yet but the interfaces
    474 	 * are receiving, can't do anything with incoming packets yet.
    475 	 * Note: we pre-check without locks held.
    476 	 */
    477 	if (IN_ADDRLIST_READER_EMPTY())
    478 		goto out;
    479 	IP_STATINC(IP_STAT_TOTAL);
    480 
    481 	/*
    482 	 * If the IP header is not aligned, slurp it up into a new
    483 	 * mbuf with space for link headers, in the event we forward
    484 	 * it.  Otherwise, if it is aligned, make sure the entire
    485 	 * base IP header is in the first mbuf of the chain.
    486 	 */
    487 	if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
    488 		if ((m = m_copyup(m, sizeof(struct ip),
    489 				  (max_linkhdr + 3) & ~3)) == NULL) {
    490 			/* XXXJRT new stat, please */
    491 			IP_STATINC(IP_STAT_TOOSMALL);
    492 			goto out;
    493 		}
    494 	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
    495 		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
    496 			IP_STATINC(IP_STAT_TOOSMALL);
    497 			goto out;
    498 		}
    499 	}
    500 	ip = mtod(m, struct ip *);
    501 	if (ip->ip_v != IPVERSION) {
    502 		IP_STATINC(IP_STAT_BADVERS);
    503 		goto out;
    504 	}
    505 	hlen = ip->ip_hl << 2;
    506 	if (hlen < sizeof(struct ip)) {	/* minimum header length */
    507 		IP_STATINC(IP_STAT_BADHLEN);
    508 		goto out;
    509 	}
    510 	if (hlen > m->m_len) {
    511 		if ((m = m_pullup(m, hlen)) == NULL) {
    512 			IP_STATINC(IP_STAT_BADHLEN);
    513 			goto out;
    514 		}
    515 		ip = mtod(m, struct ip *);
    516 	}
    517 
    518 	/*
    519 	 * RFC1122: packets with a multicast source address are
    520 	 * not allowed.
    521 	 */
    522 	if (IN_MULTICAST(ip->ip_src.s_addr)) {
    523 		IP_STATINC(IP_STAT_BADADDR);
    524 		goto out;
    525 	}
    526 
    527 	/* 127/8 must not appear on wire - RFC1122 */
    528 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
    529 	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
    530 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
    531 			IP_STATINC(IP_STAT_BADADDR);
    532 			goto out;
    533 		}
    534 	}
    535 
    536 	switch (m->m_pkthdr.csum_flags &
    537 		((ifp->if_csum_flags_rx & M_CSUM_IPv4) |
    538 		 M_CSUM_IPv4_BAD)) {
    539 	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
    540 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
    541 		IP_STATINC(IP_STAT_BADSUM);
    542 		goto out;
    543 
    544 	case M_CSUM_IPv4:
    545 		/* Checksum was okay. */
    546 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
    547 		break;
    548 
    549 	default:
    550 		/*
    551 		 * Must compute it ourselves.  Maybe skip checksum on
    552 		 * loopback interfaces.
    553 		 */
    554 		if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) ||
    555 		    ip_do_loopback_cksum)) {
    556 			INET_CSUM_COUNTER_INCR(&ip_swcsum);
    557 			if (in_cksum(m, hlen) != 0) {
    558 				IP_STATINC(IP_STAT_BADSUM);
    559 				goto out;
    560 			}
    561 		}
    562 		break;
    563 	}
    564 
    565 	/* Retrieve the packet length. */
    566 	len = ntohs(ip->ip_len);
    567 
    568 	/*
    569 	 * Check for additional length bogosity
    570 	 */
    571 	if (len < hlen) {
    572 		IP_STATINC(IP_STAT_BADLEN);
    573 		goto out;
    574 	}
    575 
    576 	/*
    577 	 * Check that the amount of data in the buffers
    578 	 * is as at least much as the IP header would have us expect.
    579 	 * Trim mbufs if longer than we expect.
    580 	 * Drop packet if shorter than we expect.
    581 	 */
    582 	if (m->m_pkthdr.len < len) {
    583 		IP_STATINC(IP_STAT_TOOSHORT);
    584 		goto out;
    585 	}
    586 	if (m->m_pkthdr.len > len) {
    587 		if (m->m_len == m->m_pkthdr.len) {
    588 			m->m_len = len;
    589 			m->m_pkthdr.len = len;
    590 		} else
    591 			m_adj(m, len - m->m_pkthdr.len);
    592 	}
    593 
    594 	/*
    595 	 * Assume that we can create a fast-forward IP flow entry
    596 	 * based on this packet.
    597 	 */
    598 	m->m_flags |= M_CANFASTFWD;
    599 
    600 	/*
    601 	 * Run through list of hooks for input packets.  If there are any
    602 	 * filters which require that additional packets in the flow are
    603 	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
    604 	 * Note that filters must _never_ set this flag, as another filter
    605 	 * in the list may have previously cleared it.
    606 	 */
    607 #if defined(IPSEC)
    608 	if (!ipsec_used || !ipsec_indone(m))
    609 #else
    610 	if (1)
    611 #endif
    612 	{
    613 		struct in_addr odst = ip->ip_dst;
    614 		bool freed;
    615 
    616 		SOFTNET_LOCK();
    617 		freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0;
    618 		SOFTNET_UNLOCK();
    619 		if (freed || m == NULL) {
    620 			goto out;
    621 		}
    622 		ip = mtod(m, struct ip *);
    623 		hlen = ip->ip_hl << 2;
    624 
    625 		/*
    626 		 * XXX The setting of "srcrt" here is to prevent ip_forward()
    627 		 * from generating ICMP redirects for packets that have
    628 		 * been redirected by a hook back out on to the same LAN that
    629 		 * they came from and is not an indication that the packet
    630 		 * is being inffluenced by source routing options.  This
    631 		 * allows things like
    632 		 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
    633 		 * where tlp0 is both on the 1.1.1.0/24 network and is the
    634 		 * default route for hosts on 1.1.1.0/24.  Of course this
    635 		 * also requires a "map tlp0 ..." to complete the story.
    636 		 * One might argue whether or not this kind of network config.
    637 		 * should be supported in this manner...
    638 		 */
    639 		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
    640 	}
    641 
    642 #ifdef ALTQ
    643 	/* XXX Temporary until ALTQ is changed to use a pfil hook */
    644 	if (altq_input) {
    645 		SOFTNET_LOCK();
    646 		if ((*altq_input)(m, AF_INET) == 0) {
    647 			/* Packet dropped by traffic conditioner. */
    648 			SOFTNET_UNLOCK();
    649 			goto out;
    650 		}
    651 		SOFTNET_UNLOCK();
    652 	}
    653 #endif
    654 
    655 	/*
    656 	 * Process options and, if not destined for us,
    657 	 * ship it on.  ip_dooptions returns 1 when an
    658 	 * error was detected (causing an icmp message
    659 	 * to be sent and the original packet to be freed).
    660 	 */
    661 	ip_nhops = 0;		/* for source routed packets */
    662 	if (hlen > sizeof (struct ip) && ip_dooptions(m))
    663 		goto out;
    664 
    665 	/*
    666 	 * Check our list of addresses, to see if the packet is for us.
    667 	 *
    668 	 * Traditional 4.4BSD did not consult IFF_UP at all.
    669 	 * The behavior here is to treat addresses on !IFF_UP interface
    670 	 * or IN_IFF_NOTREADY addresses as not mine.
    671 	 */
    672 	downmatch = 0;
    673 	s = pserialize_read_enter();
    674 	ia = ip_match_our_address(ifp, ip, &downmatch);
    675 	if (ia != NULL) {
    676 		pserialize_read_exit(s);
    677 		goto ours;
    678 	}
    679 
    680 	if (ifp->if_flags & IFF_BROADCAST) {
    681 		ia = ip_match_our_address_broadcast(ifp, ip);
    682 		if (ia != NULL) {
    683 			pserialize_read_exit(s);
    684 			goto ours;
    685 		}
    686 	}
    687 	pserialize_read_exit(s);
    688 
    689 	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
    690 #ifdef MROUTING
    691 		extern struct socket *ip_mrouter;
    692 
    693 		if (ip_mrouter) {
    694 			/*
    695 			 * If we are acting as a multicast router, all
    696 			 * incoming multicast packets are passed to the
    697 			 * kernel-level multicast forwarding function.
    698 			 * The packet is returned (relatively) intact; if
    699 			 * ip_mforward() returns a non-zero value, the packet
    700 			 * must be discarded, else it may be accepted below.
    701 			 *
    702 			 * (The IP ident field is put in the same byte order
    703 			 * as expected when ip_mforward() is called from
    704 			 * ip_output().)
    705 			 */
    706 			SOFTNET_LOCK();
    707 			if (ip_mforward(m, ifp) != 0) {
    708 				SOFTNET_UNLOCK();
    709 				IP_STATINC(IP_STAT_CANTFORWARD);
    710 				goto out;
    711 			}
    712 			SOFTNET_UNLOCK();
    713 
    714 			/*
    715 			 * The process-level routing demon needs to receive
    716 			 * all multicast IGMP packets, whether or not this
    717 			 * host belongs to their destination groups.
    718 			 */
    719 			if (ip->ip_p == IPPROTO_IGMP) {
    720 				goto ours;
    721 			}
    722 			IP_STATINC(IP_STAT_CANTFORWARD);
    723 		}
    724 #endif
    725 		/*
    726 		 * See if we belong to the destination multicast group on the
    727 		 * arrival interface.
    728 		 */
    729 		if (!in_multi_group(ip->ip_dst, ifp, 0)) {
    730 			IP_STATINC(IP_STAT_CANTFORWARD);
    731 			goto out;
    732 		}
    733 		goto ours;
    734 	}
    735 	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
    736 	    in_nullhost(ip->ip_dst))
    737 		goto ours;
    738 
    739 	/*
    740 	 * Not for us; forward if possible and desirable.
    741 	 */
    742 	if (ipforwarding == 0) {
    743 		m_put_rcvif_psref(ifp, &psref);
    744 		IP_STATINC(IP_STAT_CANTFORWARD);
    745 		m_freem(m);
    746 	} else {
    747 		/*
    748 		 * If ip_dst matched any of my address on !IFF_UP interface,
    749 		 * and there's no IFF_UP interface that matches ip_dst,
    750 		 * send icmp unreach.  Forwarding it will result in in-kernel
    751 		 * forwarding loop till TTL goes to 0.
    752 		 */
    753 		if (downmatch) {
    754 			m_put_rcvif_psref(ifp, &psref);
    755 			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
    756 			IP_STATINC(IP_STAT_CANTFORWARD);
    757 			return;
    758 		}
    759 #ifdef IPSEC
    760 		/* Perform IPsec, if any. */
    761 		if (ipsec_used) {
    762 			SOFTNET_LOCK();
    763 			if (ipsec4_input(m, IP_FORWARDING |
    764 			    (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) {
    765 				SOFTNET_UNLOCK();
    766 				goto out;
    767 			}
    768 			SOFTNET_UNLOCK();
    769 		}
    770 #endif
    771 		ip_forward(m, srcrt, ifp);
    772 		m_put_rcvif_psref(ifp, &psref);
    773 	}
    774 	return;
    775 
    776 ours:
    777 	m_put_rcvif_psref(ifp, &psref);
    778 	ifp = NULL;
    779 
    780 	/*
    781 	 * If offset or IP_MF are set, must reassemble.
    782 	 */
    783 	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
    784 		/*
    785 		 * Pass to IP reassembly mechanism.
    786 		 */
    787 		if (ip_reass_packet(&m, ip) != 0) {
    788 			/* Failed; invalid fragment(s) or packet. */
    789 			goto out;
    790 		}
    791 		if (m == NULL) {
    792 			/* More fragments should come; silently return. */
    793 			goto out;
    794 		}
    795 		/*
    796 		 * Reassembly is done, we have the final packet.
    797 		 * Updated cached data in local variable(s).
    798 		 */
    799 		ip = mtod(m, struct ip *);
    800 		hlen = ip->ip_hl << 2;
    801 	}
    802 
    803 #ifdef IPSEC
    804 	/*
    805 	 * Enforce IPsec policy checking if we are seeing last header.
    806 	 * Note that we do not visit this with protocols with PCB layer
    807 	 * code - like UDP/TCP/raw IP.
    808 	 */
    809 	if (ipsec_used &&
    810 	    (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
    811 		SOFTNET_LOCK();
    812 		if (ipsec4_input(m, 0) != 0) {
    813 			SOFTNET_UNLOCK();
    814 			goto out;
    815 		}
    816 		SOFTNET_UNLOCK();
    817 	}
    818 #endif
    819 
    820 	/*
    821 	 * Switch out to protocol's input routine.
    822 	 */
    823 #if IFA_STATS
    824 	if (ia && ip) {
    825 		struct in_ifaddr *_ia;
    826 		/*
    827 		 * Keep a reference from ip_match_our_address with psref
    828 		 * is expensive, so explore ia here again.
    829 		 */
    830 		s = pserialize_read_enter();
    831 		_ia = in_get_ia(ip->ip_dst.s_addr);
    832 		_ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
    833 		pserialize_read_exit(s);
    834 	}
    835 #endif
    836 	IP_STATINC(IP_STAT_DELIVERED);
    837 
    838 	const int off = hlen, nh = ip->ip_p;
    839 
    840 	SOFTNET_LOCK();
    841 	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
    842 	SOFTNET_UNLOCK();
    843 	return;
    844 
    845 out:
    846 	m_put_rcvif_psref(ifp, &psref);
    847 	if (m != NULL)
    848 		m_freem(m);
    849 }
    850 
    851 /*
    852  * IP timer processing.
    853  */
    854 void
    855 ip_slowtimo(void)
    856 {
    857 
    858 	mutex_enter(softnet_lock);
    859 	KERNEL_LOCK(1, NULL);
    860 
    861 	ip_reass_slowtimo();
    862 
    863 	KERNEL_UNLOCK_ONE(NULL);
    864 	mutex_exit(softnet_lock);
    865 }
    866 
    867 /*
    868  * IP drain processing.
    869  */
    870 void
    871 ip_drain(void)
    872 {
    873 
    874 	KERNEL_LOCK(1, NULL);
    875 	ip_reass_drain();
    876 	KERNEL_UNLOCK_ONE(NULL);
    877 }
    878 
    879 /*
    880  * ip_dooptions: perform option processing on a datagram, possibly discarding
    881  * it if bad options are encountered, or forwarding it if source-routed.
    882  *
    883  * => Returns true if packet has been forwarded/freed.
    884  * => Returns false if the packet should be processed further.
    885  */
    886 static bool
    887 ip_dooptions(struct mbuf *m)
    888 {
    889 	struct ip *ip = mtod(m, struct ip *);
    890 	u_char *cp, *cp0;
    891 	struct ip_timestamp *ipt;
    892 	struct in_ifaddr *ia;
    893 	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
    894 	struct in_addr dst;
    895 	n_time ntime;
    896 	struct ifaddr *ifa;
    897 	int s;
    898 
    899 	dst = ip->ip_dst;
    900 	cp = (u_char *)(ip + 1);
    901 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
    902 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
    903 		opt = cp[IPOPT_OPTVAL];
    904 		if (opt == IPOPT_EOL)
    905 			break;
    906 		if (opt == IPOPT_NOP)
    907 			optlen = 1;
    908 		else {
    909 			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
    910 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    911 				goto bad;
    912 			}
    913 			optlen = cp[IPOPT_OLEN];
    914 			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
    915 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    916 				goto bad;
    917 			}
    918 		}
    919 		switch (opt) {
    920 
    921 		default:
    922 			break;
    923 
    924 		/*
    925 		 * Source routing with record.
    926 		 * Find interface with current destination address.
    927 		 * If none on this machine then drop if strictly routed,
    928 		 * or do nothing if loosely routed.
    929 		 * Record interface address and bring up next address
    930 		 * component.  If strictly routed make sure next
    931 		 * address is on directly accessible net.
    932 		 */
    933 		case IPOPT_LSRR:
    934 		case IPOPT_SSRR:
    935 			if (ip_allowsrcrt == 0) {
    936 				type = ICMP_UNREACH;
    937 				code = ICMP_UNREACH_NET_PROHIB;
    938 				goto bad;
    939 			}
    940 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
    941 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
    942 				goto bad;
    943 			}
    944 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
    945 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
    946 				goto bad;
    947 			}
    948 			ipaddr.sin_addr = ip->ip_dst;
    949 
    950 			s = pserialize_read_enter();
    951 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
    952 			if (ifa == NULL) {
    953 				pserialize_read_exit(s);
    954 				if (opt == IPOPT_SSRR) {
    955 					type = ICMP_UNREACH;
    956 					code = ICMP_UNREACH_SRCFAIL;
    957 					goto bad;
    958 				}
    959 				/*
    960 				 * Loose routing, and not at next destination
    961 				 * yet; nothing to do except forward.
    962 				 */
    963 				break;
    964 			}
    965 			pserialize_read_exit(s);
    966 
    967 			off--;			/* 0 origin */
    968 			if ((off + sizeof(struct in_addr)) > optlen) {
    969 				/*
    970 				 * End of source route.  Should be for us.
    971 				 */
    972 				save_rte(cp, ip->ip_src);
    973 				break;
    974 			}
    975 			/*
    976 			 * locate outgoing interface
    977 			 */
    978 			memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
    979 			    sizeof(ipaddr.sin_addr));
    980 			s = pserialize_read_enter();
    981 			if (opt == IPOPT_SSRR) {
    982 				ifa = ifa_ifwithladdr(sintosa(&ipaddr));
    983 				if (ifa != NULL)
    984 					ia = ifatoia(ifa);
    985 				else
    986 					ia = NULL;
    987 			} else {
    988 				ia = ip_rtaddr(ipaddr.sin_addr);
    989 			}
    990 			if (ia == NULL) {
    991 				type = ICMP_UNREACH;
    992 				code = ICMP_UNREACH_SRCFAIL;
    993 				pserialize_read_exit(s);
    994 				goto bad;
    995 			}
    996 			ip->ip_dst = ipaddr.sin_addr;
    997 			bcopy((void *)&ia->ia_addr.sin_addr,
    998 			    (void *)(cp + off), sizeof(struct in_addr));
    999 			pserialize_read_exit(s);
   1000 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1001 			/*
   1002 			 * Let ip_intr's mcast routing check handle mcast pkts
   1003 			 */
   1004 			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
   1005 			break;
   1006 
   1007 		case IPOPT_RR:
   1008 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
   1009 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
   1010 				goto bad;
   1011 			}
   1012 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
   1013 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
   1014 				goto bad;
   1015 			}
   1016 			/*
   1017 			 * If no space remains, ignore.
   1018 			 */
   1019 			off--;			/* 0 origin */
   1020 			if ((off + sizeof(struct in_addr)) > optlen)
   1021 				break;
   1022 			memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
   1023 			    sizeof(ipaddr.sin_addr));
   1024 			/*
   1025 			 * locate outgoing interface; if we're the destination,
   1026 			 * use the incoming interface (should be same).
   1027 			 */
   1028 			s = pserialize_read_enter();
   1029 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
   1030 			if (ifa == NULL) {
   1031 				ia = ip_rtaddr(ipaddr.sin_addr);
   1032 				if (ia == NULL) {
   1033 					pserialize_read_exit(s);
   1034 					type = ICMP_UNREACH;
   1035 					code = ICMP_UNREACH_HOST;
   1036 					goto bad;
   1037 				}
   1038 			} else {
   1039 				ia = ifatoia(ifa);
   1040 			}
   1041 			bcopy((void *)&ia->ia_addr.sin_addr,
   1042 			    (void *)(cp + off), sizeof(struct in_addr));
   1043 			pserialize_read_exit(s);
   1044 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
   1045 			break;
   1046 
   1047 		case IPOPT_TS:
   1048 			code = cp - (u_char *)ip;
   1049 			ipt = (struct ip_timestamp *)cp;
   1050 			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
   1051 				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
   1052 				goto bad;
   1053 			}
   1054 			if (ipt->ipt_ptr < 5) {
   1055 				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
   1056 				goto bad;
   1057 			}
   1058 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
   1059 				if (++ipt->ipt_oflw == 0) {
   1060 					code = (u_char *)&ipt->ipt_ptr -
   1061 					    (u_char *)ip;
   1062 					goto bad;
   1063 				}
   1064 				break;
   1065 			}
   1066 			cp0 = (cp + ipt->ipt_ptr - 1);
   1067 			switch (ipt->ipt_flg) {
   1068 
   1069 			case IPOPT_TS_TSONLY:
   1070 				break;
   1071 
   1072 			case IPOPT_TS_TSANDADDR: {
   1073 				struct ifnet *rcvif;
   1074 				int _s, _ss;
   1075 
   1076 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1077 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1078 					code = (u_char *)&ipt->ipt_ptr -
   1079 					    (u_char *)ip;
   1080 					goto bad;
   1081 				}
   1082 				ipaddr.sin_addr = dst;
   1083 				_ss = pserialize_read_enter();
   1084 				rcvif = m_get_rcvif(m, &_s);
   1085 				ifa = ifaof_ifpforaddr(sintosa(&ipaddr), rcvif);
   1086 				m_put_rcvif(rcvif, &_s);
   1087 				if (ifa == NULL) {
   1088 					pserialize_read_exit(_ss);
   1089 					break;
   1090 				}
   1091 				ia = ifatoia(ifa);
   1092 				bcopy(&ia->ia_addr.sin_addr,
   1093 				    cp0, sizeof(struct in_addr));
   1094 				pserialize_read_exit(_ss);
   1095 				ipt->ipt_ptr += sizeof(struct in_addr);
   1096 				break;
   1097 			}
   1098 
   1099 			case IPOPT_TS_PRESPEC:
   1100 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
   1101 				    sizeof(struct in_addr) > ipt->ipt_len) {
   1102 					code = (u_char *)&ipt->ipt_ptr -
   1103 					    (u_char *)ip;
   1104 					goto bad;
   1105 				}
   1106 				memcpy(&ipaddr.sin_addr, cp0,
   1107 				    sizeof(struct in_addr));
   1108 				s = pserialize_read_enter();
   1109 				ifa = ifa_ifwithaddr(sintosa(&ipaddr));
   1110 				if (ifa == NULL) {
   1111 					pserialize_read_exit(s);
   1112 					continue;
   1113 				}
   1114 				pserialize_read_exit(s);
   1115 				ipt->ipt_ptr += sizeof(struct in_addr);
   1116 				break;
   1117 
   1118 			default:
   1119 				/* XXX can't take &ipt->ipt_flg */
   1120 				code = (u_char *)&ipt->ipt_ptr -
   1121 				    (u_char *)ip + 1;
   1122 				goto bad;
   1123 			}
   1124 			ntime = iptime();
   1125 			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
   1126 			memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
   1127 			    sizeof(n_time));
   1128 			ipt->ipt_ptr += sizeof(n_time);
   1129 		}
   1130 	}
   1131 	if (forward) {
   1132 		struct ifnet *rcvif;
   1133 		struct psref _psref;
   1134 
   1135 		if (ip_forwsrcrt == 0) {
   1136 			type = ICMP_UNREACH;
   1137 			code = ICMP_UNREACH_SRCFAIL;
   1138 			goto bad;
   1139 		}
   1140 
   1141 		rcvif = m_get_rcvif_psref(m, &_psref);
   1142 		if (__predict_false(rcvif == NULL)) {
   1143 			type = ICMP_UNREACH;
   1144 			code = ICMP_UNREACH_HOST;
   1145 			goto bad;
   1146 		}
   1147 		ip_forward(m, 1, rcvif);
   1148 		m_put_rcvif_psref(rcvif, &_psref);
   1149 		return true;
   1150 	}
   1151 	return false;
   1152 bad:
   1153 	icmp_error(m, type, code, 0, 0);
   1154 	IP_STATINC(IP_STAT_BADOPTIONS);
   1155 	return true;
   1156 }
   1157 
   1158 /*
   1159  * ip_rtaddr: given address of next destination (final or next hop),
   1160  * return internet address info of interface to be used to get there.
   1161  */
   1162 static struct in_ifaddr *
   1163 ip_rtaddr(struct in_addr dst)
   1164 {
   1165 	struct rtentry *rt;
   1166 	union {
   1167 		struct sockaddr		dst;
   1168 		struct sockaddr_in	dst4;
   1169 	} u;
   1170 	struct route *ro;
   1171 
   1172 	sockaddr_in_init(&u.dst4, &dst, 0);
   1173 
   1174 	SOFTNET_LOCK();
   1175 	ro = percpu_getref(ipforward_rt_percpu);
   1176 	rt = rtcache_lookup(ro, &u.dst);
   1177 	percpu_putref(ipforward_rt_percpu);
   1178 	SOFTNET_UNLOCK();
   1179 	if (rt == NULL)
   1180 		return NULL;
   1181 
   1182 	return ifatoia(rt->rt_ifa);
   1183 }
   1184 
   1185 /*
   1186  * save_rte: save incoming source route for use in replies, to be picked
   1187  * up later by ip_srcroute if the receiver is interested.
   1188  */
   1189 static void
   1190 save_rte(u_char *option, struct in_addr dst)
   1191 {
   1192 	unsigned olen;
   1193 
   1194 	olen = option[IPOPT_OLEN];
   1195 	if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
   1196 		return;
   1197 	memcpy((void *)ip_srcrt.srcopt, (void *)option, olen);
   1198 	ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
   1199 	ip_srcrt.dst = dst;
   1200 }
   1201 
   1202 /*
   1203  * Retrieve incoming source route for use in replies,
   1204  * in the same form used by setsockopt.
   1205  * The first hop is placed before the options, will be removed later.
   1206  */
   1207 struct mbuf *
   1208 ip_srcroute(void)
   1209 {
   1210 	struct in_addr *p, *q;
   1211 	struct mbuf *m;
   1212 
   1213 	if (ip_nhops == 0)
   1214 		return NULL;
   1215 	m = m_get(M_DONTWAIT, MT_SOOPTS);
   1216 	if (m == 0)
   1217 		return NULL;
   1218 
   1219 	MCLAIM(m, &inetdomain.dom_mowner);
   1220 #define OPTSIZ	(sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
   1221 
   1222 	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
   1223 	m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
   1224 	    OPTSIZ;
   1225 
   1226 	/*
   1227 	 * First save first hop for return route
   1228 	 */
   1229 	p = &ip_srcrt.route[ip_nhops - 1];
   1230 	*(mtod(m, struct in_addr *)) = *p--;
   1231 
   1232 	/*
   1233 	 * Copy option fields and padding (nop) to mbuf.
   1234 	 */
   1235 	ip_srcrt.nop = IPOPT_NOP;
   1236 	ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
   1237 	memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop,
   1238 	    OPTSIZ);
   1239 	q = (struct in_addr *)(mtod(m, char *) +
   1240 	    sizeof(struct in_addr) + OPTSIZ);
   1241 #undef OPTSIZ
   1242 	/*
   1243 	 * Record return path as an IP source route,
   1244 	 * reversing the path (pointers are now aligned).
   1245 	 */
   1246 	while (p >= ip_srcrt.route) {
   1247 		*q++ = *p--;
   1248 	}
   1249 	/*
   1250 	 * Last hop goes to final destination.
   1251 	 */
   1252 	*q = ip_srcrt.dst;
   1253 	return (m);
   1254 }
   1255 
   1256 const int inetctlerrmap[PRC_NCMDS] = {
   1257 	[PRC_MSGSIZE] = EMSGSIZE,
   1258 	[PRC_HOSTDEAD] = EHOSTDOWN,
   1259 	[PRC_HOSTUNREACH] = EHOSTUNREACH,
   1260 	[PRC_UNREACH_NET] = EHOSTUNREACH,
   1261 	[PRC_UNREACH_HOST] = EHOSTUNREACH,
   1262 	[PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
   1263 	[PRC_UNREACH_PORT] = ECONNREFUSED,
   1264 	[PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
   1265 	[PRC_PARAMPROB] = ENOPROTOOPT,
   1266 };
   1267 
   1268 void
   1269 ip_fasttimo(void)
   1270 {
   1271 	if (ip_drainwanted) {
   1272 		ip_drain();
   1273 		ip_drainwanted = 0;
   1274 	}
   1275 }
   1276 
   1277 void
   1278 ip_drainstub(void)
   1279 {
   1280 	ip_drainwanted = 1;
   1281 }
   1282 
   1283 /*
   1284  * Forward a packet.  If some error occurs return the sender
   1285  * an icmp packet.  Note we can't always generate a meaningful
   1286  * icmp message because icmp doesn't have a large enough repertoire
   1287  * of codes and types.
   1288  *
   1289  * If not forwarding, just drop the packet.  This could be confusing
   1290  * if ipforwarding was zero but some routing protocol was advancing
   1291  * us as a gateway to somewhere.  However, we must let the routing
   1292  * protocol deal with that.
   1293  *
   1294  * The srcrt parameter indicates whether the packet is being forwarded
   1295  * via a source route.
   1296  */
   1297 static void
   1298 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif)
   1299 {
   1300 	struct ip *ip = mtod(m, struct ip *);
   1301 	struct rtentry *rt;
   1302 	int error, type = 0, code = 0, destmtu = 0;
   1303 	struct mbuf *mcopy;
   1304 	n_long dest;
   1305 	union {
   1306 		struct sockaddr		dst;
   1307 		struct sockaddr_in	dst4;
   1308 	} u;
   1309 	uint64_t *ips;
   1310 	struct route *ro;
   1311 
   1312 	KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software "
   1313 	    "interrupt handler; synchronization assumptions violated");
   1314 
   1315 	/*
   1316 	 * We are now in the output path.
   1317 	 */
   1318 	MCLAIM(m, &ip_tx_mowner);
   1319 
   1320 	/*
   1321 	 * Clear any in-bound checksum flags for this packet.
   1322 	 */
   1323 	m->m_pkthdr.csum_flags = 0;
   1324 
   1325 	dest = 0;
   1326 	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
   1327 		IP_STATINC(IP_STAT_CANTFORWARD);
   1328 		m_freem(m);
   1329 		return;
   1330 	}
   1331 
   1332 	SOFTNET_LOCK();
   1333 
   1334 	if (ip->ip_ttl <= IPTTLDEC) {
   1335 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
   1336 		SOFTNET_UNLOCK();
   1337 		return;
   1338 	}
   1339 
   1340 	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
   1341 
   1342 	ro = percpu_getref(ipforward_rt_percpu);
   1343 	if ((rt = rtcache_lookup(ro, &u.dst)) == NULL) {
   1344 		percpu_putref(ipforward_rt_percpu);
   1345 		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
   1346 		SOFTNET_UNLOCK();
   1347 		return;
   1348 	}
   1349 
   1350 	/*
   1351 	 * Save at most 68 bytes of the packet in case
   1352 	 * we need to generate an ICMP message to the src.
   1353 	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
   1354 	 */
   1355 	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
   1356 	if (mcopy)
   1357 		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
   1358 
   1359 	ip->ip_ttl -= IPTTLDEC;
   1360 
   1361 	/*
   1362 	 * If forwarding packet using same interface that it came in on,
   1363 	 * perhaps should send a redirect to sender to shortcut a hop.
   1364 	 * Only send redirect if source is sending directly to us,
   1365 	 * and if packet was not source routed (or has any options).
   1366 	 * Also, don't send redirect if forwarding using a default route
   1367 	 * or a route modified by a redirect.
   1368 	 */
   1369 	if (rt->rt_ifp == rcvif &&
   1370 	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
   1371 	    !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
   1372 	    ipsendredirects && !srcrt) {
   1373 		if (rt->rt_ifa &&
   1374 		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
   1375 		    ifatoia(rt->rt_ifa)->ia_subnet) {
   1376 			if (rt->rt_flags & RTF_GATEWAY)
   1377 				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
   1378 			else
   1379 				dest = ip->ip_dst.s_addr;
   1380 			/*
   1381 			 * Router requirements says to only send host
   1382 			 * redirects.
   1383 			 */
   1384 			type = ICMP_REDIRECT;
   1385 			code = ICMP_REDIRECT_HOST;
   1386 		}
   1387 	}
   1388 
   1389 	error = ip_output(m, NULL, ro,
   1390 	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
   1391 	    NULL, NULL);
   1392 
   1393 	if (error) {
   1394 		IP_STATINC(IP_STAT_CANTFORWARD);
   1395 		goto error;
   1396 	}
   1397 
   1398 	ips = IP_STAT_GETREF();
   1399 	ips[IP_STAT_FORWARD]++;
   1400 
   1401 	if (type) {
   1402 		ips[IP_STAT_REDIRECTSENT]++;
   1403 		IP_STAT_PUTREF();
   1404 		goto redirect;
   1405 	}
   1406 
   1407 	IP_STAT_PUTREF();
   1408 	if (mcopy) {
   1409 #ifdef GATEWAY
   1410 		if (mcopy->m_flags & M_CANFASTFWD)
   1411 			ipflow_create(ro, mcopy);
   1412 #endif
   1413 		m_freem(mcopy);
   1414 	}
   1415 
   1416 	percpu_putref(ipforward_rt_percpu);
   1417 	SOFTNET_UNLOCK();
   1418 	return;
   1419 
   1420 redirect:
   1421 error:
   1422 	if (mcopy == NULL) {
   1423 		percpu_putref(ipforward_rt_percpu);
   1424 		SOFTNET_UNLOCK();
   1425 		return;
   1426 	}
   1427 
   1428 	switch (error) {
   1429 
   1430 	case 0:				/* forwarded, but need redirect */
   1431 		/* type, code set above */
   1432 		break;
   1433 
   1434 	case ENETUNREACH:		/* shouldn't happen, checked above */
   1435 	case EHOSTUNREACH:
   1436 	case ENETDOWN:
   1437 	case EHOSTDOWN:
   1438 	default:
   1439 		type = ICMP_UNREACH;
   1440 		code = ICMP_UNREACH_HOST;
   1441 		break;
   1442 
   1443 	case EMSGSIZE:
   1444 		type = ICMP_UNREACH;
   1445 		code = ICMP_UNREACH_NEEDFRAG;
   1446 
   1447 		if ((rt = rtcache_validate(ro)) != NULL)
   1448 			destmtu = rt->rt_ifp->if_mtu;
   1449 #ifdef IPSEC
   1450 		if (ipsec_used)
   1451 			(void)ipsec4_forward(mcopy, &destmtu);
   1452 #endif
   1453 		IP_STATINC(IP_STAT_CANTFRAG);
   1454 		break;
   1455 
   1456 	case ENOBUFS:
   1457 		/*
   1458 		 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812,
   1459 		 * Requirements for IP Version 4 Routers.  Source quench can
   1460 		 * big problem under DoS attacks or if the underlying
   1461 		 * interface is rate-limited.
   1462 		 */
   1463 		if (mcopy)
   1464 			m_freem(mcopy);
   1465 		percpu_putref(ipforward_rt_percpu);
   1466 		SOFTNET_UNLOCK();
   1467 		return;
   1468 	}
   1469 	icmp_error(mcopy, type, code, dest, destmtu);
   1470 	percpu_putref(ipforward_rt_percpu);
   1471 	SOFTNET_UNLOCK();
   1472 }
   1473 
   1474 void
   1475 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
   1476     struct mbuf *m)
   1477 {
   1478 	struct socket *so = inp->inp_socket;
   1479 	ifnet_t *ifp;
   1480 	int inpflags = inp->inp_flags;
   1481 	struct psref psref;
   1482 
   1483 	ifp = m_get_rcvif_psref(m, &psref);
   1484 	if (__predict_false(ifp == NULL))
   1485 		return; /* XXX should report error? */
   1486 
   1487 	if (so->so_options & SO_TIMESTAMP
   1488 #ifdef SO_OTIMESTAMP
   1489 	    || so->so_options & SO_OTIMESTAMP
   1490 #endif
   1491 	    ) {
   1492 		struct timeval tv;
   1493 
   1494 		microtime(&tv);
   1495 #ifdef SO_OTIMESTAMP
   1496 		if (so->so_options & SO_OTIMESTAMP) {
   1497 			struct timeval50 tv50;
   1498 			timeval_to_timeval50(&tv, &tv50);
   1499 			*mp = sbcreatecontrol((void *) &tv50, sizeof(tv50),
   1500 			    SCM_OTIMESTAMP, SOL_SOCKET);
   1501 		} else
   1502 #endif
   1503 		*mp = sbcreatecontrol((void *) &tv, sizeof(tv),
   1504 		    SCM_TIMESTAMP, SOL_SOCKET);
   1505 		if (*mp)
   1506 			mp = &(*mp)->m_next;
   1507 	}
   1508 	if (inpflags & INP_RECVDSTADDR) {
   1509 		*mp = sbcreatecontrol((void *) &ip->ip_dst,
   1510 		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
   1511 		if (*mp)
   1512 			mp = &(*mp)->m_next;
   1513 	}
   1514 	if (inpflags & INP_RECVPKTINFO) {
   1515 		struct in_pktinfo ipi;
   1516 		ipi.ipi_addr = ip->ip_src;
   1517 		ipi.ipi_ifindex = ifp->if_index;
   1518 		*mp = sbcreatecontrol((void *) &ipi,
   1519 		    sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP);
   1520 		if (*mp)
   1521 			mp = &(*mp)->m_next;
   1522 	}
   1523 	if (inpflags & INP_PKTINFO) {
   1524 		struct in_pktinfo ipi;
   1525 		ipi.ipi_addr = ip->ip_dst;
   1526 		ipi.ipi_ifindex = ifp->if_index;
   1527 		*mp = sbcreatecontrol((void *) &ipi,
   1528 		    sizeof(ipi), IP_PKTINFO, IPPROTO_IP);
   1529 		if (*mp)
   1530 			mp = &(*mp)->m_next;
   1531 	}
   1532 	if (inpflags & INP_RECVIF) {
   1533 		struct sockaddr_dl sdl;
   1534 
   1535 		sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0,
   1536 		    NULL, 0);
   1537 		*mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
   1538 		if (*mp)
   1539 			mp = &(*mp)->m_next;
   1540 	}
   1541 	if (inpflags & INP_RECVTTL) {
   1542 		*mp = sbcreatecontrol((void *) &ip->ip_ttl,
   1543 		    sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
   1544 		if (*mp)
   1545 			mp = &(*mp)->m_next;
   1546 	}
   1547 	m_put_rcvif_psref(ifp, &psref);
   1548 }
   1549 
   1550 /*
   1551  * sysctl helper routine for net.inet.ip.forwsrcrt.
   1552  */
   1553 static int
   1554 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
   1555 {
   1556 	int error, tmp;
   1557 	struct sysctlnode node;
   1558 
   1559 	node = *rnode;
   1560 	tmp = ip_forwsrcrt;
   1561 	node.sysctl_data = &tmp;
   1562 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1563 	if (error || newp == NULL)
   1564 		return (error);
   1565 
   1566 	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
   1567 	    0, NULL, NULL, NULL);
   1568 	if (error)
   1569 		return (error);
   1570 
   1571 	ip_forwsrcrt = tmp;
   1572 
   1573 	return (0);
   1574 }
   1575 
   1576 /*
   1577  * sysctl helper routine for net.inet.ip.mtudisctimeout.  checks the
   1578  * range of the new value and tweaks timers if it changes.
   1579  */
   1580 static int
   1581 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
   1582 {
   1583 	int error, tmp;
   1584 	struct sysctlnode node;
   1585 
   1586 	node = *rnode;
   1587 	tmp = ip_mtudisc_timeout;
   1588 	node.sysctl_data = &tmp;
   1589 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
   1590 	if (error || newp == NULL)
   1591 		return (error);
   1592 	if (tmp < 0)
   1593 		return (EINVAL);
   1594 
   1595 	mutex_enter(softnet_lock);
   1596 
   1597 	ip_mtudisc_timeout = tmp;
   1598 	rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
   1599 
   1600 	mutex_exit(softnet_lock);
   1601 
   1602 	return (0);
   1603 }
   1604 
   1605 static int
   1606 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
   1607 {
   1608 
   1609 	return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
   1610 }
   1611 
   1612 static void
   1613 sysctl_net_inet_ip_setup(struct sysctllog **clog)
   1614 {
   1615 	sysctl_createv(clog, 0, NULL, NULL,
   1616 		       CTLFLAG_PERMANENT,
   1617 		       CTLTYPE_NODE, "inet",
   1618 		       SYSCTL_DESCR("PF_INET related settings"),
   1619 		       NULL, 0, NULL, 0,
   1620 		       CTL_NET, PF_INET, CTL_EOL);
   1621 	sysctl_createv(clog, 0, NULL, NULL,
   1622 		       CTLFLAG_PERMANENT,
   1623 		       CTLTYPE_NODE, "ip",
   1624 		       SYSCTL_DESCR("IPv4 related settings"),
   1625 		       NULL, 0, NULL, 0,
   1626 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
   1627 
   1628 	sysctl_createv(clog, 0, NULL, NULL,
   1629 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1630 		       CTLTYPE_INT, "forwarding",
   1631 		       SYSCTL_DESCR("Enable forwarding of INET datagrams"),
   1632 		       NULL, 0, &ipforwarding, 0,
   1633 		       CTL_NET, PF_INET, IPPROTO_IP,
   1634 		       IPCTL_FORWARDING, CTL_EOL);
   1635 	sysctl_createv(clog, 0, NULL, NULL,
   1636 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1637 		       CTLTYPE_INT, "redirect",
   1638 		       SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
   1639 		       NULL, 0, &ipsendredirects, 0,
   1640 		       CTL_NET, PF_INET, IPPROTO_IP,
   1641 		       IPCTL_SENDREDIRECTS, CTL_EOL);
   1642 	sysctl_createv(clog, 0, NULL, NULL,
   1643 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1644 		       CTLTYPE_INT, "ttl",
   1645 		       SYSCTL_DESCR("Default TTL for an INET datagram"),
   1646 		       NULL, 0, &ip_defttl, 0,
   1647 		       CTL_NET, PF_INET, IPPROTO_IP,
   1648 		       IPCTL_DEFTTL, CTL_EOL);
   1649 #ifdef IPCTL_DEFMTU
   1650 	sysctl_createv(clog, 0, NULL, NULL,
   1651 		       CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
   1652 		       CTLTYPE_INT, "mtu",
   1653 		       SYSCTL_DESCR("Default MTA for an INET route"),
   1654 		       NULL, 0, &ip_mtu, 0,
   1655 		       CTL_NET, PF_INET, IPPROTO_IP,
   1656 		       IPCTL_DEFMTU, CTL_EOL);
   1657 #endif /* IPCTL_DEFMTU */
   1658 	sysctl_createv(clog, 0, NULL, NULL,
   1659 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1660 		       CTLTYPE_INT, "forwsrcrt",
   1661 		       SYSCTL_DESCR("Enable forwarding of source-routed "
   1662 				    "datagrams"),
   1663 		       sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
   1664 		       CTL_NET, PF_INET, IPPROTO_IP,
   1665 		       IPCTL_FORWSRCRT, CTL_EOL);
   1666 	sysctl_createv(clog, 0, NULL, NULL,
   1667 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1668 		       CTLTYPE_INT, "directed-broadcast",
   1669 		       SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
   1670 		       NULL, 0, &ip_directedbcast, 0,
   1671 		       CTL_NET, PF_INET, IPPROTO_IP,
   1672 		       IPCTL_DIRECTEDBCAST, CTL_EOL);
   1673 	sysctl_createv(clog, 0, NULL, NULL,
   1674 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1675 		       CTLTYPE_INT, "allowsrcrt",
   1676 		       SYSCTL_DESCR("Accept source-routed datagrams"),
   1677 		       NULL, 0, &ip_allowsrcrt, 0,
   1678 		       CTL_NET, PF_INET, IPPROTO_IP,
   1679 		       IPCTL_ALLOWSRCRT, CTL_EOL);
   1680 
   1681 	sysctl_createv(clog, 0, NULL, NULL,
   1682 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1683 		       CTLTYPE_INT, "mtudisc",
   1684 		       SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
   1685 		       NULL, 0, &ip_mtudisc, 0,
   1686 		       CTL_NET, PF_INET, IPPROTO_IP,
   1687 		       IPCTL_MTUDISC, CTL_EOL);
   1688 	sysctl_createv(clog, 0, NULL, NULL,
   1689 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1690 		       CTLTYPE_INT, "anonportmin",
   1691 		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
   1692 		       sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
   1693 		       CTL_NET, PF_INET, IPPROTO_IP,
   1694 		       IPCTL_ANONPORTMIN, CTL_EOL);
   1695 	sysctl_createv(clog, 0, NULL, NULL,
   1696 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1697 		       CTLTYPE_INT, "anonportmax",
   1698 		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
   1699 		       sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
   1700 		       CTL_NET, PF_INET, IPPROTO_IP,
   1701 		       IPCTL_ANONPORTMAX, CTL_EOL);
   1702 	sysctl_createv(clog, 0, NULL, NULL,
   1703 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1704 		       CTLTYPE_INT, "mtudisctimeout",
   1705 		       SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
   1706 		       sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0,
   1707 		       CTL_NET, PF_INET, IPPROTO_IP,
   1708 		       IPCTL_MTUDISCTIMEOUT, CTL_EOL);
   1709 #ifndef IPNOPRIVPORTS
   1710 	sysctl_createv(clog, 0, NULL, NULL,
   1711 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1712 		       CTLTYPE_INT, "lowportmin",
   1713 		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
   1714 				    "to assign"),
   1715 		       sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
   1716 		       CTL_NET, PF_INET, IPPROTO_IP,
   1717 		       IPCTL_LOWPORTMIN, CTL_EOL);
   1718 	sysctl_createv(clog, 0, NULL, NULL,
   1719 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1720 		       CTLTYPE_INT, "lowportmax",
   1721 		       SYSCTL_DESCR("Highest privileged ephemeral port number "
   1722 				    "to assign"),
   1723 		       sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
   1724 		       CTL_NET, PF_INET, IPPROTO_IP,
   1725 		       IPCTL_LOWPORTMAX, CTL_EOL);
   1726 #endif /* IPNOPRIVPORTS */
   1727 #if NGRE > 0
   1728 	sysctl_createv(clog, 0, NULL, NULL,
   1729 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1730 		       CTLTYPE_INT, "grettl",
   1731 		       SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
   1732 		       NULL, 0, &ip_gre_ttl, 0,
   1733 		       CTL_NET, PF_INET, IPPROTO_IP,
   1734 		       IPCTL_GRE_TTL, CTL_EOL);
   1735 #endif /* NGRE */
   1736 	sysctl_createv(clog, 0, NULL, NULL,
   1737 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1738 		       CTLTYPE_INT, "checkinterface",
   1739 		       SYSCTL_DESCR("Enable receive side of Strong ES model "
   1740 				    "from RFC1122"),
   1741 		       NULL, 0, &ip_checkinterface, 0,
   1742 		       CTL_NET, PF_INET, IPPROTO_IP,
   1743 		       IPCTL_CHECKINTERFACE, CTL_EOL);
   1744 	sysctl_createv(clog, 0, NULL, NULL,
   1745 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1746 		       CTLTYPE_INT, "random_id",
   1747 		       SYSCTL_DESCR("Assign random ip_id values"),
   1748 		       NULL, 0, &ip_do_randomid, 0,
   1749 		       CTL_NET, PF_INET, IPPROTO_IP,
   1750 		       IPCTL_RANDOMID, CTL_EOL);
   1751 	sysctl_createv(clog, 0, NULL, NULL,
   1752 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1753 		       CTLTYPE_INT, "do_loopback_cksum",
   1754 		       SYSCTL_DESCR("Perform IP checksum on loopback"),
   1755 		       NULL, 0, &ip_do_loopback_cksum, 0,
   1756 		       CTL_NET, PF_INET, IPPROTO_IP,
   1757 		       IPCTL_LOOPBACKCKSUM, CTL_EOL);
   1758 	sysctl_createv(clog, 0, NULL, NULL,
   1759 		       CTLFLAG_PERMANENT,
   1760 		       CTLTYPE_STRUCT, "stats",
   1761 		       SYSCTL_DESCR("IP statistics"),
   1762 		       sysctl_net_inet_ip_stats, 0, NULL, 0,
   1763 		       CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
   1764 		       CTL_EOL);
   1765 #if NARP
   1766 	sysctl_createv(clog, 0, NULL, NULL,
   1767 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1768 		       CTLTYPE_INT, "dad_count",
   1769 		       SYSCTL_DESCR("Number of Duplicate Address Detection "
   1770 				    "probes to send"),
   1771 		       NULL, 0, &ip_dad_count, 0,
   1772 		       CTL_NET, PF_INET, IPPROTO_IP,
   1773 		       IPCTL_DAD_COUNT, CTL_EOL);
   1774 #endif
   1775 
   1776 	/* anonportalgo RFC6056 subtree */
   1777 	const struct sysctlnode *portalgo_node;
   1778 	sysctl_createv(clog, 0, NULL, &portalgo_node,
   1779 		       CTLFLAG_PERMANENT,
   1780 		       CTLTYPE_NODE, "anonportalgo",
   1781 		       SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"),
   1782 	    	       NULL, 0, NULL, 0,
   1783 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL);
   1784 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1785 		       CTLFLAG_PERMANENT,
   1786 		       CTLTYPE_STRING, "available",
   1787 		       SYSCTL_DESCR("available algorithms"),
   1788 		       sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
   1789 		       CTL_CREATE, CTL_EOL);
   1790 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1791 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1792 		       CTLTYPE_STRING, "selected",
   1793 		       SYSCTL_DESCR("selected algorithm"),
   1794 		       sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN,
   1795 		       CTL_CREATE, CTL_EOL);
   1796 	sysctl_createv(clog, 0, &portalgo_node, NULL,
   1797 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
   1798 		       CTLTYPE_STRUCT, "reserve",
   1799 		       SYSCTL_DESCR("bitmap of reserved ports"),
   1800 		       sysctl_portalgo_reserve4, 0, NULL, 0,
   1801 		       CTL_CREATE, CTL_EOL);
   1802 }
   1803 
   1804 void
   1805 ip_statinc(u_int stat)
   1806 {
   1807 
   1808 	KASSERT(stat < IP_NSTATS);
   1809 	IP_STATINC(stat);
   1810 }
   1811