xref: /netbsd-src/sys/netinet/ip_input.c (revision e89934bbf778a6d6d6894877c4da59d0c7835b0f)
1 /*	$NetBSD: ip_input.c,v 1.349 2017/02/07 02:38:08 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 1.349 2017/02/07 02:38:08 ozaki-r Exp $");
95 
96 #ifdef _KERNEL_OPT
97 #include "opt_inet.h"
98 #include "opt_compat_netbsd.h"
99 #include "opt_gateway.h"
100 #include "opt_ipsec.h"
101 #include "opt_mrouting.h"
102 #include "opt_mbuftrace.h"
103 #include "opt_inet_csum.h"
104 #include "opt_net_mpsafe.h"
105 #endif
106 
107 #include "arp.h"
108 
109 #include <sys/param.h>
110 #include <sys/systm.h>
111 #include <sys/cpu.h>
112 #include <sys/mbuf.h>
113 #include <sys/domain.h>
114 #include <sys/protosw.h>
115 #include <sys/socket.h>
116 #include <sys/socketvar.h>
117 #include <sys/errno.h>
118 #include <sys/time.h>
119 #include <sys/kernel.h>
120 #include <sys/pool.h>
121 #include <sys/sysctl.h>
122 #include <sys/kauth.h>
123 
124 #include <net/if.h>
125 #include <net/if_dl.h>
126 #include <net/route.h>
127 #include <net/pktqueue.h>
128 #include <net/pfil.h>
129 
130 #include <netinet/in.h>
131 #include <netinet/in_systm.h>
132 #include <netinet/ip.h>
133 #include <netinet/in_pcb.h>
134 #include <netinet/in_proto.h>
135 #include <netinet/in_var.h>
136 #include <netinet/ip_var.h>
137 #include <netinet/ip_private.h>
138 #include <netinet/ip_icmp.h>
139 /* just for gif_ttl */
140 #include <netinet/in_gif.h>
141 #include "gif.h"
142 #include <net/if_gre.h>
143 #include "gre.h"
144 
145 #ifdef MROUTING
146 #include <netinet/ip_mroute.h>
147 #endif
148 #include <netinet/portalgo.h>
149 
150 #ifdef IPSEC
151 #include <netipsec/ipsec.h>
152 #endif
153 
154 #ifndef	IPFORWARDING
155 #ifdef GATEWAY
156 #define	IPFORWARDING	1	/* forward IP packets not for us */
157 #else /* GATEWAY */
158 #define	IPFORWARDING	0	/* don't forward IP packets not for us */
159 #endif /* GATEWAY */
160 #endif /* IPFORWARDING */
161 #ifndef	IPSENDREDIRECTS
162 #define	IPSENDREDIRECTS	1
163 #endif
164 #ifndef IPFORWSRCRT
165 #define	IPFORWSRCRT	1	/* forward source-routed packets */
166 #endif
167 #ifndef IPALLOWSRCRT
168 #define	IPALLOWSRCRT	1	/* allow source-routed packets */
169 #endif
170 #ifndef IPMTUDISC
171 #define IPMTUDISC	1
172 #endif
173 #ifndef IPMTUDISCTIMEOUT
174 #define IPMTUDISCTIMEOUT (10 * 60)	/* as per RFC 1191 */
175 #endif
176 
177 #ifdef COMPAT_50
178 #include <compat/sys/time.h>
179 #include <compat/sys/socket.h>
180 #endif
181 
182 /*
183  * Note: DIRECTED_BROADCAST is handled this way so that previous
184  * configuration using this option will Just Work.
185  */
186 #ifndef IPDIRECTEDBCAST
187 #ifdef DIRECTED_BROADCAST
188 #define IPDIRECTEDBCAST	1
189 #else
190 #define	IPDIRECTEDBCAST	0
191 #endif /* DIRECTED_BROADCAST */
192 #endif /* IPDIRECTEDBCAST */
193 int	ipforwarding = IPFORWARDING;
194 int	ipsendredirects = IPSENDREDIRECTS;
195 int	ip_defttl = IPDEFTTL;
196 int	ip_forwsrcrt = IPFORWSRCRT;
197 int	ip_directedbcast = IPDIRECTEDBCAST;
198 int	ip_allowsrcrt = IPALLOWSRCRT;
199 int	ip_mtudisc = IPMTUDISC;
200 int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
201 #ifdef DIAGNOSTIC
202 int	ipprintfs = 0;
203 #endif
204 
205 int	ip_do_randomid = 0;
206 
207 /*
208  * XXX - Setting ip_checkinterface mostly implements the receive side of
209  * the Strong ES model described in RFC 1122, but since the routing table
210  * and transmit implementation do not implement the Strong ES model,
211  * setting this to 1 results in an odd hybrid.
212  *
213  * XXX - ip_checkinterface currently must be disabled if you use ipnat
214  * to translate the destination address to another local interface.
215  *
216  * XXX - ip_checkinterface must be disabled if you add IP aliases
217  * to the loopback interface instead of the interface where the
218  * packets for those addresses are received.
219  */
220 static int		ip_checkinterface	__read_mostly = 0;
221 
222 struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
223 
224 pktqueue_t *		ip_pktq			__read_mostly;
225 pfil_head_t *		inet_pfil_hook		__read_mostly;
226 ipid_state_t *		ip_ids			__read_mostly;
227 percpu_t *		ipstat_percpu		__read_mostly;
228 
229 static percpu_t		*ipforward_rt_percpu	__cacheline_aligned;
230 
231 uint16_t ip_id;
232 
233 #ifdef INET_CSUM_COUNTERS
234 #include <sys/device.h>
235 
236 struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
237     NULL, "inet", "hwcsum bad");
238 struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
239     NULL, "inet", "hwcsum ok");
240 struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
241     NULL, "inet", "swcsum");
242 
243 #define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
244 
245 EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
246 EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
247 EVCNT_ATTACH_STATIC(ip_swcsum);
248 
249 #else
250 
251 #define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
252 
253 #endif /* INET_CSUM_COUNTERS */
254 
255 /*
256  * We need to save the IP options in case a protocol wants to respond
257  * to an incoming packet over the same route if the packet got here
258  * using IP source routing.  This allows connection establishment and
259  * maintenance when the remote end is on a network that is not known
260  * to us.
261  */
262 
263 static int	ip_nhops = 0;
264 
265 static	struct ip_srcrt {
266 	struct	in_addr dst;			/* final destination */
267 	char	nop;				/* one NOP to align */
268 	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
269 	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
270 } ip_srcrt;
271 
272 static int ip_drainwanted;
273 
274 struct	sockaddr_in ipaddr = {
275 	.sin_len = sizeof(ipaddr),
276 	.sin_family = AF_INET,
277 };
278 
279 static void save_rte(u_char *, struct in_addr);
280 
281 #ifdef MBUFTRACE
282 struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
283 struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
284 #endif
285 
286 static void		ipintr(void *);
287 static void		ip_input(struct mbuf *);
288 static void		ip_forward(struct mbuf *, int, struct ifnet *);
289 static bool		ip_dooptions(struct mbuf *);
290 static struct in_ifaddr *ip_rtaddr(struct in_addr, struct psref *);
291 static void		sysctl_net_inet_ip_setup(struct sysctllog **);
292 
293 static struct in_ifaddr	*ip_match_our_address(struct ifnet *, struct ip *,
294 			    int *);
295 static struct in_ifaddr	*ip_match_our_address_broadcast(struct ifnet *,
296 			    struct ip *);
297 
298 #ifdef NET_MPSAFE
299 #define	SOFTNET_LOCK()		mutex_enter(softnet_lock)
300 #define	SOFTNET_UNLOCK()	mutex_exit(softnet_lock)
301 #else
302 #define	SOFTNET_LOCK()		KASSERT(mutex_owned(softnet_lock))
303 #define	SOFTNET_UNLOCK()	KASSERT(mutex_owned(softnet_lock))
304 #endif
305 
306 /*
307  * IP initialization: fill in IP protocol switch table.
308  * All protocols not implemented in kernel go to raw IP protocol handler.
309  */
310 void
311 ip_init(void)
312 {
313 	const struct protosw *pr;
314 
315 	in_init();
316 	sysctl_net_inet_ip_setup(NULL);
317 
318 	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
319 	KASSERT(pr != NULL);
320 
321 	ip_pktq = pktq_create(IFQ_MAXLEN, ipintr, NULL);
322 	KASSERT(ip_pktq != NULL);
323 
324 	for (u_int i = 0; i < IPPROTO_MAX; i++) {
325 		ip_protox[i] = pr - inetsw;
326 	}
327 	for (pr = inetdomain.dom_protosw;
328 	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
329 		if (pr->pr_domain->dom_family == PF_INET &&
330 		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
331 			ip_protox[pr->pr_protocol] = pr - inetsw;
332 
333 	ip_reass_init();
334 
335 	ip_ids = ip_id_init();
336 	ip_id = time_uptime & 0xfffff;
337 
338 #ifdef GATEWAY
339 	ipflow_init();
340 #endif
341 
342 	/* Register our Packet Filter hook. */
343 	inet_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET);
344 	KASSERT(inet_pfil_hook != NULL);
345 
346 #ifdef MBUFTRACE
347 	MOWNER_ATTACH(&ip_tx_mowner);
348 	MOWNER_ATTACH(&ip_rx_mowner);
349 #endif /* MBUFTRACE */
350 
351 	ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
352 
353 	ipforward_rt_percpu = percpu_alloc(sizeof(struct route));
354 	if (ipforward_rt_percpu == NULL)
355 		panic("failed to allocate ipforward_rt_percpu");
356 }
357 
358 static struct in_ifaddr *
359 ip_match_our_address(struct ifnet *ifp, struct ip *ip, int *downmatch)
360 {
361 	struct in_ifaddr *ia = NULL;
362 	int checkif;
363 
364 	/*
365 	 * Enable a consistency check between the destination address
366 	 * and the arrival interface for a unicast packet (the RFC 1122
367 	 * strong ES model) if IP forwarding is disabled and the packet
368 	 * is not locally generated.
369 	 *
370 	 * XXX - Checking also should be disabled if the destination
371 	 * address is ipnat'ed to a different interface.
372 	 *
373 	 * XXX - Checking is incompatible with IP aliases added
374 	 * to the loopback interface instead of the interface where
375 	 * the packets are received.
376 	 *
377 	 * XXX - We need to add a per ifaddr flag for this so that
378 	 * we get finer grain control.
379 	 */
380 	checkif = ip_checkinterface && (ipforwarding == 0) &&
381 	    (ifp->if_flags & IFF_LOOPBACK) == 0;
382 
383 	IN_ADDRHASH_READER_FOREACH(ia, ip->ip_dst.s_addr) {
384 		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
385 			if (ia->ia4_flags & IN_IFF_NOTREADY)
386 				continue;
387 			if (checkif && ia->ia_ifp != ifp)
388 				continue;
389 			if ((ia->ia_ifp->if_flags & IFF_UP) != 0 &&
390 			    (ia->ia4_flags & IN_IFF_DETACHED) == 0)
391 				break;
392 			else
393 				(*downmatch)++;
394 		}
395 	}
396 
397 	return ia;
398 }
399 
400 static struct in_ifaddr *
401 ip_match_our_address_broadcast(struct ifnet *ifp, struct ip *ip)
402 {
403 	struct in_ifaddr *ia = NULL;
404 	struct ifaddr *ifa;
405 
406 	IFADDR_READER_FOREACH(ifa, ifp) {
407 		if (ifa->ifa_addr->sa_family != AF_INET)
408 			continue;
409 		ia = ifatoia(ifa);
410 		if (ia->ia4_flags & (IN_IFF_NOTREADY | IN_IFF_DETACHED))
411 			continue;
412 		if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
413 		    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
414 		    /*
415 		     * Look for all-0's host part (old broadcast addr),
416 		     * either for subnet or net.
417 		     */
418 		    ip->ip_dst.s_addr == ia->ia_subnet ||
419 		    ip->ip_dst.s_addr == ia->ia_net)
420 			goto matched;
421 		/*
422 		 * An interface with IP address zero accepts
423 		 * all packets that arrive on that interface.
424 		 */
425 		if (in_nullhost(ia->ia_addr.sin_addr))
426 			goto matched;
427 	}
428 	ia = NULL;
429 
430 matched:
431 	return ia;
432 }
433 
434 /*
435  * IP software interrupt routine.
436  */
437 static void
438 ipintr(void *arg __unused)
439 {
440 	struct mbuf *m;
441 
442 	KASSERT(cpu_softintr_p());
443 
444 #ifndef NET_MPSAFE
445 	mutex_enter(softnet_lock);
446 #endif
447 	while ((m = pktq_dequeue(ip_pktq)) != NULL) {
448 		ip_input(m);
449 	}
450 #ifndef NET_MPSAFE
451 	mutex_exit(softnet_lock);
452 #endif
453 }
454 
455 /*
456  * IP input routine.  Checksum and byte swap header.  If fragmented
457  * try to reassemble.  Process options.  Pass to next level.
458  */
459 static void
460 ip_input(struct mbuf *m)
461 {
462 	struct ip *ip = NULL;
463 	struct in_ifaddr *ia = NULL;
464 	int hlen = 0, len;
465 	int downmatch;
466 	int srcrt = 0;
467 	ifnet_t *ifp;
468 	struct psref psref;
469 	int s;
470 
471 	KASSERTMSG(cpu_softintr_p(), "ip_input: not in the software "
472 	    "interrupt handler; synchronization assumptions violated");
473 
474 	MCLAIM(m, &ip_rx_mowner);
475 	KASSERT((m->m_flags & M_PKTHDR) != 0);
476 
477 	ifp = m_get_rcvif_psref(m, &psref);
478 	if (__predict_false(ifp == NULL))
479 		goto out;
480 
481 	/*
482 	 * If no IP addresses have been set yet but the interfaces
483 	 * are receiving, can't do anything with incoming packets yet.
484 	 * Note: we pre-check without locks held.
485 	 */
486 	if (IN_ADDRLIST_READER_EMPTY())
487 		goto out;
488 	IP_STATINC(IP_STAT_TOTAL);
489 
490 	/*
491 	 * If the IP header is not aligned, slurp it up into a new
492 	 * mbuf with space for link headers, in the event we forward
493 	 * it.  Otherwise, if it is aligned, make sure the entire
494 	 * base IP header is in the first mbuf of the chain.
495 	 */
496 	if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
497 		if ((m = m_copyup(m, sizeof(struct ip),
498 				  (max_linkhdr + 3) & ~3)) == NULL) {
499 			/* XXXJRT new stat, please */
500 			IP_STATINC(IP_STAT_TOOSMALL);
501 			goto out;
502 		}
503 	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
504 		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
505 			IP_STATINC(IP_STAT_TOOSMALL);
506 			goto out;
507 		}
508 	}
509 	ip = mtod(m, struct ip *);
510 	if (ip->ip_v != IPVERSION) {
511 		IP_STATINC(IP_STAT_BADVERS);
512 		goto out;
513 	}
514 	hlen = ip->ip_hl << 2;
515 	if (hlen < sizeof(struct ip)) {	/* minimum header length */
516 		IP_STATINC(IP_STAT_BADHLEN);
517 		goto out;
518 	}
519 	if (hlen > m->m_len) {
520 		if ((m = m_pullup(m, hlen)) == NULL) {
521 			IP_STATINC(IP_STAT_BADHLEN);
522 			goto out;
523 		}
524 		ip = mtod(m, struct ip *);
525 	}
526 
527 	/*
528 	 * RFC1122: packets with a multicast source address are
529 	 * not allowed.
530 	 */
531 	if (IN_MULTICAST(ip->ip_src.s_addr)) {
532 		IP_STATINC(IP_STAT_BADADDR);
533 		goto out;
534 	}
535 
536 	/* 127/8 must not appear on wire - RFC1122 */
537 	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
538 	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
539 		if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
540 			IP_STATINC(IP_STAT_BADADDR);
541 			goto out;
542 		}
543 	}
544 
545 	switch (m->m_pkthdr.csum_flags &
546 		((ifp->if_csum_flags_rx & M_CSUM_IPv4) |
547 		 M_CSUM_IPv4_BAD)) {
548 	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
549 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
550 		IP_STATINC(IP_STAT_BADSUM);
551 		goto out;
552 
553 	case M_CSUM_IPv4:
554 		/* Checksum was okay. */
555 		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
556 		break;
557 
558 	default:
559 		/*
560 		 * Must compute it ourselves.  Maybe skip checksum on
561 		 * loopback interfaces.
562 		 */
563 		if (__predict_true(!(ifp->if_flags & IFF_LOOPBACK) ||
564 		    ip_do_loopback_cksum)) {
565 			INET_CSUM_COUNTER_INCR(&ip_swcsum);
566 			if (in_cksum(m, hlen) != 0) {
567 				IP_STATINC(IP_STAT_BADSUM);
568 				goto out;
569 			}
570 		}
571 		break;
572 	}
573 
574 	/* Retrieve the packet length. */
575 	len = ntohs(ip->ip_len);
576 
577 	/*
578 	 * Check for additional length bogosity
579 	 */
580 	if (len < hlen) {
581 		IP_STATINC(IP_STAT_BADLEN);
582 		goto out;
583 	}
584 
585 	/*
586 	 * Check that the amount of data in the buffers
587 	 * is as at least much as the IP header would have us expect.
588 	 * Trim mbufs if longer than we expect.
589 	 * Drop packet if shorter than we expect.
590 	 */
591 	if (m->m_pkthdr.len < len) {
592 		IP_STATINC(IP_STAT_TOOSHORT);
593 		goto out;
594 	}
595 	if (m->m_pkthdr.len > len) {
596 		if (m->m_len == m->m_pkthdr.len) {
597 			m->m_len = len;
598 			m->m_pkthdr.len = len;
599 		} else
600 			m_adj(m, len - m->m_pkthdr.len);
601 	}
602 
603 	/*
604 	 * Assume that we can create a fast-forward IP flow entry
605 	 * based on this packet.
606 	 */
607 	m->m_flags |= M_CANFASTFWD;
608 
609 	/*
610 	 * Run through list of hooks for input packets.  If there are any
611 	 * filters which require that additional packets in the flow are
612 	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
613 	 * Note that filters must _never_ set this flag, as another filter
614 	 * in the list may have previously cleared it.
615 	 */
616 #if defined(IPSEC)
617 	if (!ipsec_used || !ipsec_indone(m))
618 #else
619 	if (1)
620 #endif
621 	{
622 		struct in_addr odst = ip->ip_dst;
623 		bool freed;
624 
625 		freed = pfil_run_hooks(inet_pfil_hook, &m, ifp, PFIL_IN) != 0;
626 		if (freed || m == NULL) {
627 			m = NULL;
628 			goto out;
629 		}
630 		ip = mtod(m, struct ip *);
631 		hlen = ip->ip_hl << 2;
632 
633 		/*
634 		 * XXX The setting of "srcrt" here is to prevent ip_forward()
635 		 * from generating ICMP redirects for packets that have
636 		 * been redirected by a hook back out on to the same LAN that
637 		 * they came from and is not an indication that the packet
638 		 * is being inffluenced by source routing options.  This
639 		 * allows things like
640 		 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
641 		 * where tlp0 is both on the 1.1.1.0/24 network and is the
642 		 * default route for hosts on 1.1.1.0/24.  Of course this
643 		 * also requires a "map tlp0 ..." to complete the story.
644 		 * One might argue whether or not this kind of network config.
645 		 * should be supported in this manner...
646 		 */
647 		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
648 	}
649 
650 #ifdef ALTQ
651 	/* XXX Temporary until ALTQ is changed to use a pfil hook */
652 	if (altq_input) {
653 		SOFTNET_LOCK();
654 		if ((*altq_input)(m, AF_INET) == 0) {
655 			/* Packet dropped by traffic conditioner. */
656 			SOFTNET_UNLOCK();
657 			m = NULL;
658 			goto out;
659 		}
660 		SOFTNET_UNLOCK();
661 	}
662 #endif
663 
664 	/*
665 	 * Process options and, if not destined for us,
666 	 * ship it on.  ip_dooptions returns 1 when an
667 	 * error was detected (causing an icmp message
668 	 * to be sent and the original packet to be freed).
669 	 */
670 	ip_nhops = 0;		/* for source routed packets */
671 	if (hlen > sizeof (struct ip) && ip_dooptions(m)) {
672 		m = NULL;
673 		goto out;
674 	}
675 
676 	/*
677 	 * Check our list of addresses, to see if the packet is for us.
678 	 *
679 	 * Traditional 4.4BSD did not consult IFF_UP at all.
680 	 * The behavior here is to treat addresses on !IFF_UP interface
681 	 * or IN_IFF_NOTREADY addresses as not mine.
682 	 */
683 	downmatch = 0;
684 	s = pserialize_read_enter();
685 	ia = ip_match_our_address(ifp, ip, &downmatch);
686 	if (ia != NULL) {
687 		pserialize_read_exit(s);
688 		goto ours;
689 	}
690 
691 	if (ifp->if_flags & IFF_BROADCAST) {
692 		ia = ip_match_our_address_broadcast(ifp, ip);
693 		if (ia != NULL) {
694 			pserialize_read_exit(s);
695 			goto ours;
696 		}
697 	}
698 	pserialize_read_exit(s);
699 
700 	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
701 #ifdef MROUTING
702 		extern struct socket *ip_mrouter;
703 
704 		if (ip_mrouter) {
705 			/*
706 			 * If we are acting as a multicast router, all
707 			 * incoming multicast packets are passed to the
708 			 * kernel-level multicast forwarding function.
709 			 * The packet is returned (relatively) intact; if
710 			 * ip_mforward() returns a non-zero value, the packet
711 			 * must be discarded, else it may be accepted below.
712 			 *
713 			 * (The IP ident field is put in the same byte order
714 			 * as expected when ip_mforward() is called from
715 			 * ip_output().)
716 			 */
717 			SOFTNET_LOCK();
718 			if (ip_mforward(m, ifp) != 0) {
719 				SOFTNET_UNLOCK();
720 				IP_STATINC(IP_STAT_CANTFORWARD);
721 				goto out;
722 			}
723 			SOFTNET_UNLOCK();
724 
725 			/*
726 			 * The process-level routing demon needs to receive
727 			 * all multicast IGMP packets, whether or not this
728 			 * host belongs to their destination groups.
729 			 */
730 			if (ip->ip_p == IPPROTO_IGMP) {
731 				goto ours;
732 			}
733 			IP_STATINC(IP_STAT_CANTFORWARD);
734 		}
735 #endif
736 		/*
737 		 * See if we belong to the destination multicast group on the
738 		 * arrival interface.
739 		 */
740 		if (!in_multi_group(ip->ip_dst, ifp, 0)) {
741 			IP_STATINC(IP_STAT_CANTFORWARD);
742 			goto out;
743 		}
744 		goto ours;
745 	}
746 	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
747 	    in_nullhost(ip->ip_dst))
748 		goto ours;
749 
750 	/*
751 	 * Not for us; forward if possible and desirable.
752 	 */
753 	if (ipforwarding == 0) {
754 		m_put_rcvif_psref(ifp, &psref);
755 		IP_STATINC(IP_STAT_CANTFORWARD);
756 		m_freem(m);
757 	} else {
758 		/*
759 		 * If ip_dst matched any of my address on !IFF_UP interface,
760 		 * and there's no IFF_UP interface that matches ip_dst,
761 		 * send icmp unreach.  Forwarding it will result in in-kernel
762 		 * forwarding loop till TTL goes to 0.
763 		 */
764 		if (downmatch) {
765 			m_put_rcvif_psref(ifp, &psref);
766 			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
767 			IP_STATINC(IP_STAT_CANTFORWARD);
768 			return;
769 		}
770 #ifdef IPSEC
771 		/* Perform IPsec, if any. */
772 		if (ipsec_used) {
773 			SOFTNET_LOCK();
774 			if (ipsec4_input(m, IP_FORWARDING |
775 			    (ip_directedbcast ? IP_ALLOWBROADCAST : 0)) != 0) {
776 				SOFTNET_UNLOCK();
777 				goto out;
778 			}
779 			SOFTNET_UNLOCK();
780 		}
781 #endif
782 		ip_forward(m, srcrt, ifp);
783 		m_put_rcvif_psref(ifp, &psref);
784 	}
785 	return;
786 
787 ours:
788 	m_put_rcvif_psref(ifp, &psref);
789 	ifp = NULL;
790 
791 	/*
792 	 * If offset or IP_MF are set, must reassemble.
793 	 */
794 	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
795 		/*
796 		 * Pass to IP reassembly mechanism.
797 		 */
798 		if (ip_reass_packet(&m, ip) != 0) {
799 			/* Failed; invalid fragment(s) or packet. */
800 			goto out;
801 		}
802 		if (m == NULL) {
803 			/* More fragments should come; silently return. */
804 			goto out;
805 		}
806 		/*
807 		 * Reassembly is done, we have the final packet.
808 		 * Updated cached data in local variable(s).
809 		 */
810 		ip = mtod(m, struct ip *);
811 		hlen = ip->ip_hl << 2;
812 	}
813 
814 #ifdef IPSEC
815 	/*
816 	 * Enforce IPsec policy checking if we are seeing last header.
817 	 * Note that we do not visit this with protocols with PCB layer
818 	 * code - like UDP/TCP/raw IP.
819 	 */
820 	if (ipsec_used &&
821 	    (inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
822 		SOFTNET_LOCK();
823 		if (ipsec4_input(m, 0) != 0) {
824 			SOFTNET_UNLOCK();
825 			goto out;
826 		}
827 		SOFTNET_UNLOCK();
828 	}
829 #endif
830 
831 	/*
832 	 * Switch out to protocol's input routine.
833 	 */
834 #if IFA_STATS
835 	if (ia && ip) {
836 		struct in_ifaddr *_ia;
837 		/*
838 		 * Keep a reference from ip_match_our_address with psref
839 		 * is expensive, so explore ia here again.
840 		 */
841 		s = pserialize_read_enter();
842 		_ia = in_get_ia(ip->ip_dst);
843 		_ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
844 		pserialize_read_exit(s);
845 	}
846 #endif
847 	IP_STATINC(IP_STAT_DELIVERED);
848 
849 	const int off = hlen, nh = ip->ip_p;
850 
851 	SOFTNET_LOCK();
852 	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
853 	SOFTNET_UNLOCK();
854 	return;
855 
856 out:
857 	m_put_rcvif_psref(ifp, &psref);
858 	if (m != NULL)
859 		m_freem(m);
860 }
861 
862 /*
863  * IP timer processing.
864  */
865 void
866 ip_slowtimo(void)
867 {
868 
869 #ifndef NET_MPSAFE
870 	mutex_enter(softnet_lock);
871 	KERNEL_LOCK(1, NULL);
872 #endif
873 
874 	ip_reass_slowtimo();
875 
876 #ifndef NET_MPSAFE
877 	KERNEL_UNLOCK_ONE(NULL);
878 	mutex_exit(softnet_lock);
879 #endif
880 }
881 
882 /*
883  * IP drain processing.
884  */
885 void
886 ip_drain(void)
887 {
888 
889 	KERNEL_LOCK(1, NULL);
890 	ip_reass_drain();
891 	KERNEL_UNLOCK_ONE(NULL);
892 }
893 
894 /*
895  * ip_dooptions: perform option processing on a datagram, possibly discarding
896  * it if bad options are encountered, or forwarding it if source-routed.
897  *
898  * => Returns true if packet has been forwarded/freed.
899  * => Returns false if the packet should be processed further.
900  */
901 static bool
902 ip_dooptions(struct mbuf *m)
903 {
904 	struct ip *ip = mtod(m, struct ip *);
905 	u_char *cp, *cp0;
906 	struct ip_timestamp *ipt;
907 	struct in_ifaddr *ia;
908 	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
909 	struct in_addr dst;
910 	n_time ntime;
911 	struct ifaddr *ifa = NULL;
912 	int s;
913 
914 	dst = ip->ip_dst;
915 	cp = (u_char *)(ip + 1);
916 	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
917 	for (; cnt > 0; cnt -= optlen, cp += optlen) {
918 		opt = cp[IPOPT_OPTVAL];
919 		if (opt == IPOPT_EOL)
920 			break;
921 		if (opt == IPOPT_NOP)
922 			optlen = 1;
923 		else {
924 			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
925 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
926 				goto bad;
927 			}
928 			optlen = cp[IPOPT_OLEN];
929 			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
930 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
931 				goto bad;
932 			}
933 		}
934 		switch (opt) {
935 
936 		default:
937 			break;
938 
939 		/*
940 		 * Source routing with record.
941 		 * Find interface with current destination address.
942 		 * If none on this machine then drop if strictly routed,
943 		 * or do nothing if loosely routed.
944 		 * Record interface address and bring up next address
945 		 * component.  If strictly routed make sure next
946 		 * address is on directly accessible net.
947 		 */
948 		case IPOPT_LSRR:
949 		case IPOPT_SSRR: {
950 			struct psref psref;
951 			if (ip_allowsrcrt == 0) {
952 				type = ICMP_UNREACH;
953 				code = ICMP_UNREACH_NET_PROHIB;
954 				goto bad;
955 			}
956 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
957 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
958 				goto bad;
959 			}
960 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
961 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
962 				goto bad;
963 			}
964 			ipaddr.sin_addr = ip->ip_dst;
965 
966 			s = pserialize_read_enter();
967 			ifa = ifa_ifwithaddr(sintosa(&ipaddr));
968 			if (ifa == NULL) {
969 				pserialize_read_exit(s);
970 				if (opt == IPOPT_SSRR) {
971 					type = ICMP_UNREACH;
972 					code = ICMP_UNREACH_SRCFAIL;
973 					goto bad;
974 				}
975 				/*
976 				 * Loose routing, and not at next destination
977 				 * yet; nothing to do except forward.
978 				 */
979 				break;
980 			}
981 			pserialize_read_exit(s);
982 
983 			off--;			/* 0 origin */
984 			if ((off + sizeof(struct in_addr)) > optlen) {
985 				/*
986 				 * End of source route.  Should be for us.
987 				 */
988 				save_rte(cp, ip->ip_src);
989 				break;
990 			}
991 			/*
992 			 * locate outgoing interface
993 			 */
994 			memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
995 			    sizeof(ipaddr.sin_addr));
996 			if (opt == IPOPT_SSRR) {
997 				ifa = ifa_ifwithladdr_psref(sintosa(&ipaddr),
998 				    &psref);
999 				if (ifa != NULL)
1000 					ia = ifatoia(ifa);
1001 				else
1002 					ia = NULL;
1003 			} else {
1004 				ia = ip_rtaddr(ipaddr.sin_addr, &psref);
1005 			}
1006 			if (ia == NULL) {
1007 				type = ICMP_UNREACH;
1008 				code = ICMP_UNREACH_SRCFAIL;
1009 				goto bad;
1010 			}
1011 			ip->ip_dst = ipaddr.sin_addr;
1012 			bcopy((void *)&ia->ia_addr.sin_addr,
1013 			    (void *)(cp + off), sizeof(struct in_addr));
1014 			ia4_release(ia, &psref);
1015 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1016 			/*
1017 			 * Let ip_intr's mcast routing check handle mcast pkts
1018 			 */
1019 			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1020 			break;
1021 		    }
1022 
1023 		case IPOPT_RR: {
1024 			struct psref psref;
1025 			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1026 				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1027 				goto bad;
1028 			}
1029 			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1030 				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1031 				goto bad;
1032 			}
1033 			/*
1034 			 * If no space remains, ignore.
1035 			 */
1036 			off--;			/* 0 origin */
1037 			if ((off + sizeof(struct in_addr)) > optlen)
1038 				break;
1039 			memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
1040 			    sizeof(ipaddr.sin_addr));
1041 			/*
1042 			 * locate outgoing interface; if we're the destination,
1043 			 * use the incoming interface (should be same).
1044 			 */
1045 			ifa = ifa_ifwithaddr_psref(sintosa(&ipaddr), &psref);
1046 			if (ifa == NULL) {
1047 				ia = ip_rtaddr(ipaddr.sin_addr, &psref);
1048 				if (ia == NULL) {
1049 					type = ICMP_UNREACH;
1050 					code = ICMP_UNREACH_HOST;
1051 					goto bad;
1052 				}
1053 			} else {
1054 				ia = ifatoia(ifa);
1055 			}
1056 			bcopy((void *)&ia->ia_addr.sin_addr,
1057 			    (void *)(cp + off), sizeof(struct in_addr));
1058 			ia4_release(ia, &psref);
1059 			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1060 			break;
1061 		    }
1062 
1063 		case IPOPT_TS:
1064 			code = cp - (u_char *)ip;
1065 			ipt = (struct ip_timestamp *)cp;
1066 			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
1067 				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
1068 				goto bad;
1069 			}
1070 			if (ipt->ipt_ptr < 5) {
1071 				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
1072 				goto bad;
1073 			}
1074 			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1075 				if (++ipt->ipt_oflw == 0) {
1076 					code = (u_char *)&ipt->ipt_ptr -
1077 					    (u_char *)ip;
1078 					goto bad;
1079 				}
1080 				break;
1081 			}
1082 			cp0 = (cp + ipt->ipt_ptr - 1);
1083 			switch (ipt->ipt_flg) {
1084 
1085 			case IPOPT_TS_TSONLY:
1086 				break;
1087 
1088 			case IPOPT_TS_TSANDADDR: {
1089 				struct ifnet *rcvif;
1090 				int _s, _ss;
1091 
1092 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1093 				    sizeof(struct in_addr) > ipt->ipt_len) {
1094 					code = (u_char *)&ipt->ipt_ptr -
1095 					    (u_char *)ip;
1096 					goto bad;
1097 				}
1098 				ipaddr.sin_addr = dst;
1099 				_ss = pserialize_read_enter();
1100 				rcvif = m_get_rcvif(m, &_s);
1101 				if (__predict_true(rcvif != NULL)) {
1102 					ifa = ifaof_ifpforaddr(sintosa(&ipaddr),
1103 					    rcvif);
1104 				}
1105 				m_put_rcvif(rcvif, &_s);
1106 				if (ifa == NULL) {
1107 					pserialize_read_exit(_ss);
1108 					break;
1109 				}
1110 				ia = ifatoia(ifa);
1111 				bcopy(&ia->ia_addr.sin_addr,
1112 				    cp0, sizeof(struct in_addr));
1113 				pserialize_read_exit(_ss);
1114 				ipt->ipt_ptr += sizeof(struct in_addr);
1115 				break;
1116 			}
1117 
1118 			case IPOPT_TS_PRESPEC:
1119 				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1120 				    sizeof(struct in_addr) > ipt->ipt_len) {
1121 					code = (u_char *)&ipt->ipt_ptr -
1122 					    (u_char *)ip;
1123 					goto bad;
1124 				}
1125 				memcpy(&ipaddr.sin_addr, cp0,
1126 				    sizeof(struct in_addr));
1127 				s = pserialize_read_enter();
1128 				ifa = ifa_ifwithaddr(sintosa(&ipaddr));
1129 				if (ifa == NULL) {
1130 					pserialize_read_exit(s);
1131 					continue;
1132 				}
1133 				pserialize_read_exit(s);
1134 				ipt->ipt_ptr += sizeof(struct in_addr);
1135 				break;
1136 
1137 			default:
1138 				/* XXX can't take &ipt->ipt_flg */
1139 				code = (u_char *)&ipt->ipt_ptr -
1140 				    (u_char *)ip + 1;
1141 				goto bad;
1142 			}
1143 			ntime = iptime();
1144 			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
1145 			memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
1146 			    sizeof(n_time));
1147 			ipt->ipt_ptr += sizeof(n_time);
1148 		}
1149 	}
1150 	if (forward) {
1151 		struct ifnet *rcvif;
1152 		struct psref _psref;
1153 
1154 		if (ip_forwsrcrt == 0) {
1155 			type = ICMP_UNREACH;
1156 			code = ICMP_UNREACH_SRCFAIL;
1157 			goto bad;
1158 		}
1159 
1160 		rcvif = m_get_rcvif_psref(m, &_psref);
1161 		if (__predict_false(rcvif == NULL)) {
1162 			type = ICMP_UNREACH;
1163 			code = ICMP_UNREACH_HOST;
1164 			goto bad;
1165 		}
1166 		ip_forward(m, 1, rcvif);
1167 		m_put_rcvif_psref(rcvif, &_psref);
1168 		return true;
1169 	}
1170 	return false;
1171 bad:
1172 	icmp_error(m, type, code, 0, 0);
1173 	IP_STATINC(IP_STAT_BADOPTIONS);
1174 	return true;
1175 }
1176 
1177 /*
1178  * ip_rtaddr: given address of next destination (final or next hop),
1179  * return internet address info of interface to be used to get there.
1180  */
1181 static struct in_ifaddr *
1182 ip_rtaddr(struct in_addr dst, struct psref *psref)
1183 {
1184 	struct rtentry *rt;
1185 	union {
1186 		struct sockaddr		dst;
1187 		struct sockaddr_in	dst4;
1188 	} u;
1189 	struct route *ro;
1190 
1191 	sockaddr_in_init(&u.dst4, &dst, 0);
1192 
1193 	ro = percpu_getref(ipforward_rt_percpu);
1194 	rt = rtcache_lookup(ro, &u.dst);
1195 	if (rt == NULL) {
1196 		percpu_putref(ipforward_rt_percpu);
1197 		return NULL;
1198 	}
1199 
1200 	ia4_acquire(ifatoia(rt->rt_ifa), psref);
1201 	rtcache_unref(rt, ro);
1202 	percpu_putref(ipforward_rt_percpu);
1203 
1204 	return ifatoia(rt->rt_ifa);
1205 }
1206 
1207 /*
1208  * save_rte: save incoming source route for use in replies, to be picked
1209  * up later by ip_srcroute if the receiver is interested.
1210  */
1211 static void
1212 save_rte(u_char *option, struct in_addr dst)
1213 {
1214 	unsigned olen;
1215 
1216 	olen = option[IPOPT_OLEN];
1217 	if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
1218 		return;
1219 	memcpy((void *)ip_srcrt.srcopt, (void *)option, olen);
1220 	ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1221 	ip_srcrt.dst = dst;
1222 }
1223 
1224 /*
1225  * Retrieve incoming source route for use in replies,
1226  * in the same form used by setsockopt.
1227  * The first hop is placed before the options, will be removed later.
1228  */
1229 struct mbuf *
1230 ip_srcroute(void)
1231 {
1232 	struct in_addr *p, *q;
1233 	struct mbuf *m;
1234 
1235 	if (ip_nhops == 0)
1236 		return NULL;
1237 	m = m_get(M_DONTWAIT, MT_SOOPTS);
1238 	if (m == 0)
1239 		return NULL;
1240 
1241 	MCLAIM(m, &inetdomain.dom_mowner);
1242 #define OPTSIZ	(sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1243 
1244 	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1245 	m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
1246 	    OPTSIZ;
1247 
1248 	/*
1249 	 * First save first hop for return route
1250 	 */
1251 	p = &ip_srcrt.route[ip_nhops - 1];
1252 	*(mtod(m, struct in_addr *)) = *p--;
1253 
1254 	/*
1255 	 * Copy option fields and padding (nop) to mbuf.
1256 	 */
1257 	ip_srcrt.nop = IPOPT_NOP;
1258 	ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1259 	memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop,
1260 	    OPTSIZ);
1261 	q = (struct in_addr *)(mtod(m, char *) +
1262 	    sizeof(struct in_addr) + OPTSIZ);
1263 #undef OPTSIZ
1264 	/*
1265 	 * Record return path as an IP source route,
1266 	 * reversing the path (pointers are now aligned).
1267 	 */
1268 	while (p >= ip_srcrt.route) {
1269 		*q++ = *p--;
1270 	}
1271 	/*
1272 	 * Last hop goes to final destination.
1273 	 */
1274 	*q = ip_srcrt.dst;
1275 	return (m);
1276 }
1277 
1278 const int inetctlerrmap[PRC_NCMDS] = {
1279 	[PRC_MSGSIZE] = EMSGSIZE,
1280 	[PRC_HOSTDEAD] = EHOSTDOWN,
1281 	[PRC_HOSTUNREACH] = EHOSTUNREACH,
1282 	[PRC_UNREACH_NET] = EHOSTUNREACH,
1283 	[PRC_UNREACH_HOST] = EHOSTUNREACH,
1284 	[PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
1285 	[PRC_UNREACH_PORT] = ECONNREFUSED,
1286 	[PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
1287 	[PRC_PARAMPROB] = ENOPROTOOPT,
1288 };
1289 
1290 void
1291 ip_fasttimo(void)
1292 {
1293 	if (ip_drainwanted) {
1294 		ip_drain();
1295 		ip_drainwanted = 0;
1296 	}
1297 }
1298 
1299 void
1300 ip_drainstub(void)
1301 {
1302 	ip_drainwanted = 1;
1303 }
1304 
1305 /*
1306  * Forward a packet.  If some error occurs return the sender
1307  * an icmp packet.  Note we can't always generate a meaningful
1308  * icmp message because icmp doesn't have a large enough repertoire
1309  * of codes and types.
1310  *
1311  * If not forwarding, just drop the packet.  This could be confusing
1312  * if ipforwarding was zero but some routing protocol was advancing
1313  * us as a gateway to somewhere.  However, we must let the routing
1314  * protocol deal with that.
1315  *
1316  * The srcrt parameter indicates whether the packet is being forwarded
1317  * via a source route.
1318  */
1319 static void
1320 ip_forward(struct mbuf *m, int srcrt, struct ifnet *rcvif)
1321 {
1322 	struct ip *ip = mtod(m, struct ip *);
1323 	struct rtentry *rt;
1324 	int error, type = 0, code = 0, destmtu = 0;
1325 	struct mbuf *mcopy;
1326 	n_long dest;
1327 	union {
1328 		struct sockaddr		dst;
1329 		struct sockaddr_in	dst4;
1330 	} u;
1331 	uint64_t *ips;
1332 	struct route *ro;
1333 
1334 	KASSERTMSG(cpu_softintr_p(), "ip_forward: not in the software "
1335 	    "interrupt handler; synchronization assumptions violated");
1336 
1337 	/*
1338 	 * We are now in the output path.
1339 	 */
1340 	MCLAIM(m, &ip_tx_mowner);
1341 
1342 	/*
1343 	 * Clear any in-bound checksum flags for this packet.
1344 	 */
1345 	m->m_pkthdr.csum_flags = 0;
1346 
1347 	dest = 0;
1348 	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1349 		IP_STATINC(IP_STAT_CANTFORWARD);
1350 		m_freem(m);
1351 		return;
1352 	}
1353 
1354 	if (ip->ip_ttl <= IPTTLDEC) {
1355 		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1356 		return;
1357 	}
1358 
1359 	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
1360 
1361 	ro = percpu_getref(ipforward_rt_percpu);
1362 	rt = rtcache_lookup(ro, &u.dst);
1363 	if (rt == NULL) {
1364 		percpu_putref(ipforward_rt_percpu);
1365 		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
1366 		return;
1367 	}
1368 
1369 	/*
1370 	 * Save at most 68 bytes of the packet in case
1371 	 * we need to generate an ICMP message to the src.
1372 	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
1373 	 */
1374 	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
1375 	if (mcopy)
1376 		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
1377 
1378 	ip->ip_ttl -= IPTTLDEC;
1379 
1380 	/*
1381 	 * If forwarding packet using same interface that it came in on,
1382 	 * perhaps should send a redirect to sender to shortcut a hop.
1383 	 * Only send redirect if source is sending directly to us,
1384 	 * and if packet was not source routed (or has any options).
1385 	 * Also, don't send redirect if forwarding using a default route
1386 	 * or a route modified by a redirect.
1387 	 */
1388 	if (rt->rt_ifp == rcvif &&
1389 	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1390 	    !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
1391 	    ipsendredirects && !srcrt) {
1392 		if (rt->rt_ifa &&
1393 		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1394 		    ifatoia(rt->rt_ifa)->ia_subnet) {
1395 			if (rt->rt_flags & RTF_GATEWAY)
1396 				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1397 			else
1398 				dest = ip->ip_dst.s_addr;
1399 			/*
1400 			 * Router requirements says to only send host
1401 			 * redirects.
1402 			 */
1403 			type = ICMP_REDIRECT;
1404 			code = ICMP_REDIRECT_HOST;
1405 		}
1406 	}
1407 	rtcache_unref(rt, ro);
1408 
1409 	error = ip_output(m, NULL, ro,
1410 	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
1411 	    NULL, NULL);
1412 
1413 	if (error) {
1414 		IP_STATINC(IP_STAT_CANTFORWARD);
1415 		goto error;
1416 	}
1417 
1418 	ips = IP_STAT_GETREF();
1419 	ips[IP_STAT_FORWARD]++;
1420 
1421 	if (type) {
1422 		ips[IP_STAT_REDIRECTSENT]++;
1423 		IP_STAT_PUTREF();
1424 		goto redirect;
1425 	}
1426 
1427 	IP_STAT_PUTREF();
1428 	if (mcopy) {
1429 #ifdef GATEWAY
1430 		if (mcopy->m_flags & M_CANFASTFWD)
1431 			ipflow_create(ro, mcopy);
1432 #endif
1433 		m_freem(mcopy);
1434 	}
1435 
1436 	percpu_putref(ipforward_rt_percpu);
1437 	return;
1438 
1439 redirect:
1440 error:
1441 	if (mcopy == NULL) {
1442 		percpu_putref(ipforward_rt_percpu);
1443 		return;
1444 	}
1445 
1446 	switch (error) {
1447 
1448 	case 0:				/* forwarded, but need redirect */
1449 		/* type, code set above */
1450 		break;
1451 
1452 	case ENETUNREACH:		/* shouldn't happen, checked above */
1453 	case EHOSTUNREACH:
1454 	case ENETDOWN:
1455 	case EHOSTDOWN:
1456 	default:
1457 		type = ICMP_UNREACH;
1458 		code = ICMP_UNREACH_HOST;
1459 		break;
1460 
1461 	case EMSGSIZE:
1462 		type = ICMP_UNREACH;
1463 		code = ICMP_UNREACH_NEEDFRAG;
1464 
1465 		if ((rt = rtcache_validate(ro)) != NULL) {
1466 			destmtu = rt->rt_ifp->if_mtu;
1467 			rtcache_unref(rt, ro);
1468 		}
1469 #ifdef IPSEC
1470 		if (ipsec_used)
1471 			(void)ipsec4_forward(mcopy, &destmtu);
1472 #endif
1473 		IP_STATINC(IP_STAT_CANTFRAG);
1474 		break;
1475 
1476 	case ENOBUFS:
1477 		/*
1478 		 * Do not generate ICMP_SOURCEQUENCH as required in RFC 1812,
1479 		 * Requirements for IP Version 4 Routers.  Source quench can
1480 		 * big problem under DoS attacks or if the underlying
1481 		 * interface is rate-limited.
1482 		 */
1483 		if (mcopy)
1484 			m_freem(mcopy);
1485 		percpu_putref(ipforward_rt_percpu);
1486 		return;
1487 	}
1488 	icmp_error(mcopy, type, code, dest, destmtu);
1489 	percpu_putref(ipforward_rt_percpu);
1490 }
1491 
1492 void
1493 ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1494     struct mbuf *m)
1495 {
1496 	struct socket *so = inp->inp_socket;
1497 	ifnet_t *ifp;
1498 	int inpflags = inp->inp_flags;
1499 	struct psref psref;
1500 
1501 	ifp = m_get_rcvif_psref(m, &psref);
1502 	if (__predict_false(ifp == NULL))
1503 		return; /* XXX should report error? */
1504 
1505 	if (so->so_options & SO_TIMESTAMP
1506 #ifdef SO_OTIMESTAMP
1507 	    || so->so_options & SO_OTIMESTAMP
1508 #endif
1509 	    ) {
1510 		struct timeval tv;
1511 
1512 		microtime(&tv);
1513 #ifdef SO_OTIMESTAMP
1514 		if (so->so_options & SO_OTIMESTAMP) {
1515 			struct timeval50 tv50;
1516 			timeval_to_timeval50(&tv, &tv50);
1517 			*mp = sbcreatecontrol((void *) &tv50, sizeof(tv50),
1518 			    SCM_OTIMESTAMP, SOL_SOCKET);
1519 		} else
1520 #endif
1521 		*mp = sbcreatecontrol((void *) &tv, sizeof(tv),
1522 		    SCM_TIMESTAMP, SOL_SOCKET);
1523 		if (*mp)
1524 			mp = &(*mp)->m_next;
1525 	}
1526 	if (inpflags & INP_RECVDSTADDR) {
1527 		*mp = sbcreatecontrol((void *) &ip->ip_dst,
1528 		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1529 		if (*mp)
1530 			mp = &(*mp)->m_next;
1531 	}
1532 	if (inpflags & INP_RECVPKTINFO) {
1533 		struct in_pktinfo ipi;
1534 		ipi.ipi_addr = ip->ip_src;
1535 		ipi.ipi_ifindex = ifp->if_index;
1536 		*mp = sbcreatecontrol((void *) &ipi,
1537 		    sizeof(ipi), IP_RECVPKTINFO, IPPROTO_IP);
1538 		if (*mp)
1539 			mp = &(*mp)->m_next;
1540 	}
1541 	if (inpflags & INP_PKTINFO) {
1542 		struct in_pktinfo ipi;
1543 		ipi.ipi_addr = ip->ip_dst;
1544 		ipi.ipi_ifindex = ifp->if_index;
1545 		*mp = sbcreatecontrol((void *) &ipi,
1546 		    sizeof(ipi), IP_PKTINFO, IPPROTO_IP);
1547 		if (*mp)
1548 			mp = &(*mp)->m_next;
1549 	}
1550 	if (inpflags & INP_RECVIF) {
1551 		struct sockaddr_dl sdl;
1552 
1553 		sockaddr_dl_init(&sdl, sizeof(sdl), ifp->if_index, 0, NULL, 0,
1554 		    NULL, 0);
1555 		*mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
1556 		if (*mp)
1557 			mp = &(*mp)->m_next;
1558 	}
1559 	if (inpflags & INP_RECVTTL) {
1560 		*mp = sbcreatecontrol((void *) &ip->ip_ttl,
1561 		    sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
1562 		if (*mp)
1563 			mp = &(*mp)->m_next;
1564 	}
1565 	m_put_rcvif_psref(ifp, &psref);
1566 }
1567 
1568 /*
1569  * sysctl helper routine for net.inet.ip.forwsrcrt.
1570  */
1571 static int
1572 sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
1573 {
1574 	int error, tmp;
1575 	struct sysctlnode node;
1576 
1577 	node = *rnode;
1578 	tmp = ip_forwsrcrt;
1579 	node.sysctl_data = &tmp;
1580 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
1581 	if (error || newp == NULL)
1582 		return (error);
1583 
1584 	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
1585 	    0, NULL, NULL, NULL);
1586 	if (error)
1587 		return (error);
1588 
1589 	ip_forwsrcrt = tmp;
1590 
1591 	return (0);
1592 }
1593 
1594 /*
1595  * sysctl helper routine for net.inet.ip.mtudisctimeout.  checks the
1596  * range of the new value and tweaks timers if it changes.
1597  */
1598 static int
1599 sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
1600 {
1601 	int error, tmp;
1602 	struct sysctlnode node;
1603 
1604 	node = *rnode;
1605 	tmp = ip_mtudisc_timeout;
1606 	node.sysctl_data = &tmp;
1607 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
1608 	if (error || newp == NULL)
1609 		return (error);
1610 	if (tmp < 0)
1611 		return (EINVAL);
1612 
1613 	/* XXX NOMPSAFE still need softnet_lock */
1614 	mutex_enter(softnet_lock);
1615 
1616 	ip_mtudisc_timeout = tmp;
1617 	rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
1618 
1619 	mutex_exit(softnet_lock);
1620 
1621 	return (0);
1622 }
1623 
1624 static int
1625 sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
1626 {
1627 
1628 	return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
1629 }
1630 
1631 static void
1632 sysctl_net_inet_ip_setup(struct sysctllog **clog)
1633 {
1634 	sysctl_createv(clog, 0, NULL, NULL,
1635 		       CTLFLAG_PERMANENT,
1636 		       CTLTYPE_NODE, "inet",
1637 		       SYSCTL_DESCR("PF_INET related settings"),
1638 		       NULL, 0, NULL, 0,
1639 		       CTL_NET, PF_INET, CTL_EOL);
1640 	sysctl_createv(clog, 0, NULL, NULL,
1641 		       CTLFLAG_PERMANENT,
1642 		       CTLTYPE_NODE, "ip",
1643 		       SYSCTL_DESCR("IPv4 related settings"),
1644 		       NULL, 0, NULL, 0,
1645 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
1646 
1647 	sysctl_createv(clog, 0, NULL, NULL,
1648 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1649 		       CTLTYPE_INT, "forwarding",
1650 		       SYSCTL_DESCR("Enable forwarding of INET datagrams"),
1651 		       NULL, 0, &ipforwarding, 0,
1652 		       CTL_NET, PF_INET, IPPROTO_IP,
1653 		       IPCTL_FORWARDING, CTL_EOL);
1654 	sysctl_createv(clog, 0, NULL, NULL,
1655 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1656 		       CTLTYPE_INT, "redirect",
1657 		       SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
1658 		       NULL, 0, &ipsendredirects, 0,
1659 		       CTL_NET, PF_INET, IPPROTO_IP,
1660 		       IPCTL_SENDREDIRECTS, CTL_EOL);
1661 	sysctl_createv(clog, 0, NULL, NULL,
1662 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1663 		       CTLTYPE_INT, "ttl",
1664 		       SYSCTL_DESCR("Default TTL for an INET datagram"),
1665 		       NULL, 0, &ip_defttl, 0,
1666 		       CTL_NET, PF_INET, IPPROTO_IP,
1667 		       IPCTL_DEFTTL, CTL_EOL);
1668 #ifdef IPCTL_DEFMTU
1669 	sysctl_createv(clog, 0, NULL, NULL,
1670 		       CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
1671 		       CTLTYPE_INT, "mtu",
1672 		       SYSCTL_DESCR("Default MTA for an INET route"),
1673 		       NULL, 0, &ip_mtu, 0,
1674 		       CTL_NET, PF_INET, IPPROTO_IP,
1675 		       IPCTL_DEFMTU, CTL_EOL);
1676 #endif /* IPCTL_DEFMTU */
1677 	sysctl_createv(clog, 0, NULL, NULL,
1678 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1679 		       CTLTYPE_INT, "forwsrcrt",
1680 		       SYSCTL_DESCR("Enable forwarding of source-routed "
1681 				    "datagrams"),
1682 		       sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
1683 		       CTL_NET, PF_INET, IPPROTO_IP,
1684 		       IPCTL_FORWSRCRT, CTL_EOL);
1685 	sysctl_createv(clog, 0, NULL, NULL,
1686 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1687 		       CTLTYPE_INT, "directed-broadcast",
1688 		       SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
1689 		       NULL, 0, &ip_directedbcast, 0,
1690 		       CTL_NET, PF_INET, IPPROTO_IP,
1691 		       IPCTL_DIRECTEDBCAST, CTL_EOL);
1692 	sysctl_createv(clog, 0, NULL, NULL,
1693 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1694 		       CTLTYPE_INT, "allowsrcrt",
1695 		       SYSCTL_DESCR("Accept source-routed datagrams"),
1696 		       NULL, 0, &ip_allowsrcrt, 0,
1697 		       CTL_NET, PF_INET, IPPROTO_IP,
1698 		       IPCTL_ALLOWSRCRT, CTL_EOL);
1699 
1700 	sysctl_createv(clog, 0, NULL, NULL,
1701 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1702 		       CTLTYPE_INT, "mtudisc",
1703 		       SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
1704 		       NULL, 0, &ip_mtudisc, 0,
1705 		       CTL_NET, PF_INET, IPPROTO_IP,
1706 		       IPCTL_MTUDISC, CTL_EOL);
1707 	sysctl_createv(clog, 0, NULL, NULL,
1708 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1709 		       CTLTYPE_INT, "anonportmin",
1710 		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
1711 		       sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
1712 		       CTL_NET, PF_INET, IPPROTO_IP,
1713 		       IPCTL_ANONPORTMIN, CTL_EOL);
1714 	sysctl_createv(clog, 0, NULL, NULL,
1715 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1716 		       CTLTYPE_INT, "anonportmax",
1717 		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
1718 		       sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
1719 		       CTL_NET, PF_INET, IPPROTO_IP,
1720 		       IPCTL_ANONPORTMAX, CTL_EOL);
1721 	sysctl_createv(clog, 0, NULL, NULL,
1722 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1723 		       CTLTYPE_INT, "mtudisctimeout",
1724 		       SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
1725 		       sysctl_net_inet_ip_pmtudto, 0, (void *)&ip_mtudisc_timeout, 0,
1726 		       CTL_NET, PF_INET, IPPROTO_IP,
1727 		       IPCTL_MTUDISCTIMEOUT, CTL_EOL);
1728 #ifndef IPNOPRIVPORTS
1729 	sysctl_createv(clog, 0, NULL, NULL,
1730 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1731 		       CTLTYPE_INT, "lowportmin",
1732 		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
1733 				    "to assign"),
1734 		       sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
1735 		       CTL_NET, PF_INET, IPPROTO_IP,
1736 		       IPCTL_LOWPORTMIN, CTL_EOL);
1737 	sysctl_createv(clog, 0, NULL, NULL,
1738 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1739 		       CTLTYPE_INT, "lowportmax",
1740 		       SYSCTL_DESCR("Highest privileged ephemeral port number "
1741 				    "to assign"),
1742 		       sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
1743 		       CTL_NET, PF_INET, IPPROTO_IP,
1744 		       IPCTL_LOWPORTMAX, CTL_EOL);
1745 #endif /* IPNOPRIVPORTS */
1746 #if NGRE > 0
1747 	sysctl_createv(clog, 0, NULL, NULL,
1748 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1749 		       CTLTYPE_INT, "grettl",
1750 		       SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
1751 		       NULL, 0, &ip_gre_ttl, 0,
1752 		       CTL_NET, PF_INET, IPPROTO_IP,
1753 		       IPCTL_GRE_TTL, CTL_EOL);
1754 #endif /* NGRE */
1755 	sysctl_createv(clog, 0, NULL, NULL,
1756 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1757 		       CTLTYPE_INT, "checkinterface",
1758 		       SYSCTL_DESCR("Enable receive side of Strong ES model "
1759 				    "from RFC1122"),
1760 		       NULL, 0, &ip_checkinterface, 0,
1761 		       CTL_NET, PF_INET, IPPROTO_IP,
1762 		       IPCTL_CHECKINTERFACE, CTL_EOL);
1763 	sysctl_createv(clog, 0, NULL, NULL,
1764 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1765 		       CTLTYPE_INT, "random_id",
1766 		       SYSCTL_DESCR("Assign random ip_id values"),
1767 		       NULL, 0, &ip_do_randomid, 0,
1768 		       CTL_NET, PF_INET, IPPROTO_IP,
1769 		       IPCTL_RANDOMID, CTL_EOL);
1770 	sysctl_createv(clog, 0, NULL, NULL,
1771 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1772 		       CTLTYPE_INT, "do_loopback_cksum",
1773 		       SYSCTL_DESCR("Perform IP checksum on loopback"),
1774 		       NULL, 0, &ip_do_loopback_cksum, 0,
1775 		       CTL_NET, PF_INET, IPPROTO_IP,
1776 		       IPCTL_LOOPBACKCKSUM, CTL_EOL);
1777 	sysctl_createv(clog, 0, NULL, NULL,
1778 		       CTLFLAG_PERMANENT,
1779 		       CTLTYPE_STRUCT, "stats",
1780 		       SYSCTL_DESCR("IP statistics"),
1781 		       sysctl_net_inet_ip_stats, 0, NULL, 0,
1782 		       CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
1783 		       CTL_EOL);
1784 #if NARP
1785 	sysctl_createv(clog, 0, NULL, NULL,
1786 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1787 		       CTLTYPE_INT, "dad_count",
1788 		       SYSCTL_DESCR("Number of Duplicate Address Detection "
1789 				    "probes to send"),
1790 		       NULL, 0, &ip_dad_count, 0,
1791 		       CTL_NET, PF_INET, IPPROTO_IP,
1792 		       IPCTL_DAD_COUNT, CTL_EOL);
1793 #endif
1794 
1795 	/* anonportalgo RFC6056 subtree */
1796 	const struct sysctlnode *portalgo_node;
1797 	sysctl_createv(clog, 0, NULL, &portalgo_node,
1798 		       CTLFLAG_PERMANENT,
1799 		       CTLTYPE_NODE, "anonportalgo",
1800 		       SYSCTL_DESCR("Anonymous Port Algorithm Selection (RFC 6056)"),
1801 	    	       NULL, 0, NULL, 0,
1802 		       CTL_NET, PF_INET, IPPROTO_IP, CTL_CREATE, CTL_EOL);
1803 	sysctl_createv(clog, 0, &portalgo_node, NULL,
1804 		       CTLFLAG_PERMANENT,
1805 		       CTLTYPE_STRING, "available",
1806 		       SYSCTL_DESCR("available algorithms"),
1807 		       sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
1808 		       CTL_CREATE, CTL_EOL);
1809 	sysctl_createv(clog, 0, &portalgo_node, NULL,
1810 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1811 		       CTLTYPE_STRING, "selected",
1812 		       SYSCTL_DESCR("selected algorithm"),
1813 		       sysctl_portalgo_selected4, 0, NULL, PORTALGO_MAXLEN,
1814 		       CTL_CREATE, CTL_EOL);
1815 	sysctl_createv(clog, 0, &portalgo_node, NULL,
1816 		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1817 		       CTLTYPE_STRUCT, "reserve",
1818 		       SYSCTL_DESCR("bitmap of reserved ports"),
1819 		       sysctl_portalgo_reserve4, 0, NULL, 0,
1820 		       CTL_CREATE, CTL_EOL);
1821 }
1822 
1823 void
1824 ip_statinc(u_int stat)
1825 {
1826 
1827 	KASSERT(stat < IP_NSTATS);
1828 	IP_STATINC(stat);
1829 }
1830