ip_input.c revision 1.288
1/*	$NetBSD: ip_input.c,v 1.288 2010/07/13 22:16:10 rmind 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 1.288 2010/07/13 22:16:10 rmind Exp $");
95
96#include "opt_inet.h"
97#include "opt_compat_netbsd.h"
98#include "opt_gateway.h"
99#include "opt_pfil_hooks.h"
100#include "opt_ipsec.h"
101#include "opt_mrouting.h"
102#include "opt_mbuftrace.h"
103#include "opt_inet_csum.h"
104
105#include <sys/param.h>
106#include <sys/systm.h>
107#include <sys/mbuf.h>
108#include <sys/domain.h>
109#include <sys/protosw.h>
110#include <sys/socket.h>
111#include <sys/socketvar.h>
112#include <sys/errno.h>
113#include <sys/time.h>
114#include <sys/kernel.h>
115#include <sys/pool.h>
116#include <sys/sysctl.h>
117#include <sys/kauth.h>
118
119#include <net/if.h>
120#include <net/if_dl.h>
121#include <net/route.h>
122#include <net/pfil.h>
123
124#include <netinet/in.h>
125#include <netinet/in_systm.h>
126#include <netinet/ip.h>
127#include <netinet/in_pcb.h>
128#include <netinet/in_proto.h>
129#include <netinet/in_var.h>
130#include <netinet/ip_var.h>
131#include <netinet/ip_private.h>
132#include <netinet/ip_icmp.h>
133/* just for gif_ttl */
134#include <netinet/in_gif.h>
135#include "gif.h"
136#include <net/if_gre.h>
137#include "gre.h"
138
139#ifdef MROUTING
140#include <netinet/ip_mroute.h>
141#endif
142
143#ifdef IPSEC
144#include <netinet6/ipsec.h>
145#include <netinet6/ipsec_private.h>
146#include <netkey/key.h>
147#endif
148#ifdef FAST_IPSEC
149#include <netipsec/ipsec.h>
150#include <netipsec/key.h>
151#endif	/* FAST_IPSEC*/
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 */
192int	ipforwarding = IPFORWARDING;
193int	ipsendredirects = IPSENDREDIRECTS;
194int	ip_defttl = IPDEFTTL;
195int	ip_forwsrcrt = IPFORWSRCRT;
196int	ip_directedbcast = IPDIRECTEDBCAST;
197int	ip_allowsrcrt = IPALLOWSRCRT;
198int	ip_mtudisc = IPMTUDISC;
199int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
200#ifdef DIAGNOSTIC
201int	ipprintfs = 0;
202#endif
203
204int	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 */
219int	ip_checkinterface = 0;
220
221
222struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
223
224int	ipqmaxlen = IFQ_MAXLEN;
225u_long	in_ifaddrhash;				/* size of hash table - 1 */
226int	in_ifaddrentries;			/* total number of addrs */
227struct in_ifaddrhead in_ifaddrhead;
228struct	in_ifaddrhashhead *in_ifaddrhashtbl;
229u_long	in_multihash;				/* size of hash table - 1 */
230int	in_multientries;			/* total number of addrs */
231struct	in_multihashhead *in_multihashtbl;
232struct	ifqueue ipintrq;
233
234uint16_t ip_id;
235
236percpu_t *ipstat_percpu;
237
238#ifdef PFIL_HOOKS
239struct pfil_head inet_pfil_hook;
240#endif
241
242struct pool inmulti_pool;
243
244#ifdef INET_CSUM_COUNTERS
245#include <sys/device.h>
246
247struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
248    NULL, "inet", "hwcsum bad");
249struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
250    NULL, "inet", "hwcsum ok");
251struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
252    NULL, "inet", "swcsum");
253
254#define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
255
256EVCNT_ATTACH_STATIC(ip_hwcsum_bad);
257EVCNT_ATTACH_STATIC(ip_hwcsum_ok);
258EVCNT_ATTACH_STATIC(ip_swcsum);
259
260#else
261
262#define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
263
264#endif /* INET_CSUM_COUNTERS */
265
266/*
267 * We need to save the IP options in case a protocol wants to respond
268 * to an incoming packet over the same route if the packet got here
269 * using IP source routing.  This allows connection establishment and
270 * maintenance when the remote end is on a network that is not known
271 * to us.
272 */
273int	ip_nhops = 0;
274static	struct ip_srcrt {
275	struct	in_addr dst;			/* final destination */
276	char	nop;				/* one NOP to align */
277	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
278	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
279} ip_srcrt;
280
281static void save_rte(u_char *, struct in_addr);
282
283#ifdef MBUFTRACE
284struct mowner ip_rx_mowner = MOWNER_INIT("internet", "rx");
285struct mowner ip_tx_mowner = MOWNER_INIT("internet", "tx");
286#endif
287
288static void sysctl_net_inet_ip_setup(struct sysctllog **);
289
290/*
291 * IP initialization: fill in IP protocol switch table.
292 * All protocols not implemented in kernel go to raw IP protocol handler.
293 */
294void
295ip_init(void)
296{
297	const struct protosw *pr;
298	int i;
299
300	sysctl_net_inet_ip_setup(NULL);
301
302	pool_init(&inmulti_pool, sizeof(struct in_multi), 0, 0, 0, "inmltpl",
303	    NULL, IPL_SOFTNET);
304
305	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
306	if (pr == 0)
307		panic("ip_init");
308	for (i = 0; i < IPPROTO_MAX; i++)
309		ip_protox[i] = pr - inetsw;
310	for (pr = inetdomain.dom_protosw;
311	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
312		if (pr->pr_domain->dom_family == PF_INET &&
313		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
314			ip_protox[pr->pr_protocol] = pr - inetsw;
315
316	ip_reass_init();
317
318	ip_initid();
319	ip_id = time_second & 0xfffff;
320
321	ipintrq.ifq_maxlen = ipqmaxlen;
322
323	TAILQ_INIT(&in_ifaddrhead);
324	in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, true,
325	    &in_ifaddrhash);
326	in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, true,
327	    &in_multihash);
328	ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout);
329#ifdef GATEWAY
330	ipflow_init(ip_hashsize);
331#endif
332
333#ifdef PFIL_HOOKS
334	/* Register our Packet Filter hook. */
335	inet_pfil_hook.ph_type = PFIL_TYPE_AF;
336	inet_pfil_hook.ph_af   = AF_INET;
337	i = pfil_head_register(&inet_pfil_hook);
338	if (i != 0)
339		printf("ip_init: WARNING: unable to register pfil hook, "
340		    "error %d\n", i);
341#endif /* PFIL_HOOKS */
342
343#ifdef MBUFTRACE
344	MOWNER_ATTACH(&ip_tx_mowner);
345	MOWNER_ATTACH(&ip_rx_mowner);
346#endif /* MBUFTRACE */
347
348	ipstat_percpu = percpu_alloc(sizeof(uint64_t) * IP_NSTATS);
349}
350
351struct	sockaddr_in ipaddr = {
352	.sin_len = sizeof(ipaddr),
353	.sin_family = AF_INET,
354};
355struct	route ipforward_rt;
356
357/*
358 * IP software interrupt routine
359 */
360void
361ipintr(void)
362{
363	int s;
364	struct mbuf *m;
365	struct ifqueue lcl_intrq;
366
367	memset(&lcl_intrq, 0, sizeof(lcl_intrq));
368	ipintrq.ifq_maxlen = ipqmaxlen;
369
370	mutex_enter(softnet_lock);
371	KERNEL_LOCK(1, NULL);
372	if (!IF_IS_EMPTY(&ipintrq)) {
373		s = splnet();
374
375		/* Take existing queue onto stack */
376		lcl_intrq = ipintrq;
377
378		/* Zero out global queue, preserving maxlen and drops */
379		ipintrq.ifq_head = NULL;
380		ipintrq.ifq_tail = NULL;
381		ipintrq.ifq_len = 0;
382		ipintrq.ifq_maxlen = lcl_intrq.ifq_maxlen;
383		ipintrq.ifq_drops = lcl_intrq.ifq_drops;
384
385		splx(s);
386	}
387	KERNEL_UNLOCK_ONE(NULL);
388	while (!IF_IS_EMPTY(&lcl_intrq)) {
389		IF_DEQUEUE(&lcl_intrq, m);
390		if (m == NULL)
391			break;
392		ip_input(m);
393	}
394	mutex_exit(softnet_lock);
395}
396
397/*
398 * Ip input routine.  Checksum and byte swap header.  If fragmented
399 * try to reassemble.  Process options.  Pass to next level.
400 */
401void
402ip_input(struct mbuf *m)
403{
404	struct ip *ip = NULL;
405	struct in_ifaddr *ia;
406	struct ifaddr *ifa;
407	int hlen = 0, len;
408	int downmatch;
409	int checkif;
410	int srcrt = 0;
411#ifdef FAST_IPSEC
412	struct m_tag *mtag;
413	struct tdb_ident *tdbi;
414	struct secpolicy *sp;
415	int error;
416#endif /* FAST_IPSEC */
417
418	MCLAIM(m, &ip_rx_mowner);
419#ifdef	DIAGNOSTIC
420	if ((m->m_flags & M_PKTHDR) == 0)
421		panic("ipintr no HDR");
422#endif
423
424	/*
425	 * If no IP addresses have been set yet but the interfaces
426	 * are receiving, can't do anything with incoming packets yet.
427	 */
428	if (TAILQ_FIRST(&in_ifaddrhead) == 0)
429		goto bad;
430	IP_STATINC(IP_STAT_TOTAL);
431	/*
432	 * If the IP header is not aligned, slurp it up into a new
433	 * mbuf with space for link headers, in the event we forward
434	 * it.  Otherwise, if it is aligned, make sure the entire
435	 * base IP header is in the first mbuf of the chain.
436	 */
437	if (IP_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
438		if ((m = m_copyup(m, sizeof(struct ip),
439				  (max_linkhdr + 3) & ~3)) == NULL) {
440			/* XXXJRT new stat, please */
441			IP_STATINC(IP_STAT_TOOSMALL);
442			return;
443		}
444	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
445		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
446			IP_STATINC(IP_STAT_TOOSMALL);
447			return;
448		}
449	}
450	ip = mtod(m, struct ip *);
451	if (ip->ip_v != IPVERSION) {
452		IP_STATINC(IP_STAT_BADVERS);
453		goto bad;
454	}
455	hlen = ip->ip_hl << 2;
456	if (hlen < sizeof(struct ip)) {	/* minimum header length */
457		IP_STATINC(IP_STAT_BADHLEN);
458		goto bad;
459	}
460	if (hlen > m->m_len) {
461		if ((m = m_pullup(m, hlen)) == 0) {
462			IP_STATINC(IP_STAT_BADHLEN);
463			return;
464		}
465		ip = mtod(m, struct ip *);
466	}
467
468	/*
469	 * RFC1122: packets with a multicast source address are
470	 * not allowed.
471	 */
472	if (IN_MULTICAST(ip->ip_src.s_addr)) {
473		IP_STATINC(IP_STAT_BADADDR);
474		goto bad;
475	}
476
477	/* 127/8 must not appear on wire - RFC1122 */
478	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
479	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
480		if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
481			IP_STATINC(IP_STAT_BADADDR);
482			goto bad;
483		}
484	}
485
486	switch (m->m_pkthdr.csum_flags &
487		((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) |
488		 M_CSUM_IPv4_BAD)) {
489	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
490		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
491		goto badcsum;
492
493	case M_CSUM_IPv4:
494		/* Checksum was okay. */
495		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
496		break;
497
498	default:
499		/*
500		 * Must compute it ourselves.  Maybe skip checksum on
501		 * loopback interfaces.
502		 */
503		if (__predict_true(!(m->m_pkthdr.rcvif->if_flags &
504				     IFF_LOOPBACK) || ip_do_loopback_cksum)) {
505			INET_CSUM_COUNTER_INCR(&ip_swcsum);
506			if (in_cksum(m, hlen) != 0)
507				goto badcsum;
508		}
509		break;
510	}
511
512	/* Retrieve the packet length. */
513	len = ntohs(ip->ip_len);
514
515	/*
516	 * Check for additional length bogosity
517	 */
518	if (len < hlen) {
519		IP_STATINC(IP_STAT_BADLEN);
520		goto bad;
521	}
522
523	/*
524	 * Check that the amount of data in the buffers
525	 * is as at least much as the IP header would have us expect.
526	 * Trim mbufs if longer than we expect.
527	 * Drop packet if shorter than we expect.
528	 */
529	if (m->m_pkthdr.len < len) {
530		IP_STATINC(IP_STAT_TOOSHORT);
531		goto bad;
532	}
533	if (m->m_pkthdr.len > len) {
534		if (m->m_len == m->m_pkthdr.len) {
535			m->m_len = len;
536			m->m_pkthdr.len = len;
537		} else
538			m_adj(m, len - m->m_pkthdr.len);
539	}
540
541#if defined(IPSEC)
542	/* ipflow (IP fast forwarding) is not compatible with IPsec. */
543	m->m_flags &= ~M_CANFASTFWD;
544#else
545	/*
546	 * Assume that we can create a fast-forward IP flow entry
547	 * based on this packet.
548	 */
549	m->m_flags |= M_CANFASTFWD;
550#endif
551
552#ifdef PFIL_HOOKS
553	/*
554	 * Run through list of hooks for input packets.  If there are any
555	 * filters which require that additional packets in the flow are
556	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
557	 * Note that filters must _never_ set this flag, as another filter
558	 * in the list may have previously cleared it.
559	 */
560	/*
561	 * let ipfilter look at packet on the wire,
562	 * not the decapsulated packet.
563	 */
564#ifdef IPSEC
565	if (!ipsec_getnhist(m))
566#elif defined(FAST_IPSEC)
567	if (!ipsec_indone(m))
568#else
569	if (1)
570#endif
571	{
572		struct in_addr odst;
573
574		odst = ip->ip_dst;
575		if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
576		    PFIL_IN) != 0)
577			return;
578		if (m == NULL)
579			return;
580		ip = mtod(m, struct ip *);
581		hlen = ip->ip_hl << 2;
582		/*
583		 * XXX The setting of "srcrt" here is to prevent ip_forward()
584		 * from generating ICMP redirects for packets that have
585		 * been redirected by a hook back out on to the same LAN that
586		 * they came from and is not an indication that the packet
587		 * is being inffluenced by source routing options.  This
588		 * allows things like
589		 * "rdr tlp0 0/0 port 80 -> 1.1.1.200 3128 tcp"
590		 * where tlp0 is both on the 1.1.1.0/24 network and is the
591		 * default route for hosts on 1.1.1.0/24.  Of course this
592		 * also requires a "map tlp0 ..." to complete the story.
593		 * One might argue whether or not this kind of network config.
594		 * should be supported in this manner...
595		 */
596		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
597	}
598#endif /* PFIL_HOOKS */
599
600#ifdef ALTQ
601	/* XXX Temporary until ALTQ is changed to use a pfil hook */
602	if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
603		/* packet dropped by traffic conditioner */
604		return;
605	}
606#endif
607
608	/*
609	 * Process options and, if not destined for us,
610	 * ship it on.  ip_dooptions returns 1 when an
611	 * error was detected (causing an icmp message
612	 * to be sent and the original packet to be freed).
613	 */
614	ip_nhops = 0;		/* for source routed packets */
615	if (hlen > sizeof (struct ip) && ip_dooptions(m))
616		return;
617
618	/*
619	 * Enable a consistency check between the destination address
620	 * and the arrival interface for a unicast packet (the RFC 1122
621	 * strong ES model) if IP forwarding is disabled and the packet
622	 * is not locally generated.
623	 *
624	 * XXX - Checking also should be disabled if the destination
625	 * address is ipnat'ed to a different interface.
626	 *
627	 * XXX - Checking is incompatible with IP aliases added
628	 * to the loopback interface instead of the interface where
629	 * the packets are received.
630	 *
631	 * XXX - We need to add a per ifaddr flag for this so that
632	 * we get finer grain control.
633	 */
634	checkif = ip_checkinterface && (ipforwarding == 0) &&
635	    (m->m_pkthdr.rcvif != NULL) &&
636	    ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0);
637
638	/*
639	 * Check our list of addresses, to see if the packet is for us.
640	 *
641	 * Traditional 4.4BSD did not consult IFF_UP at all.
642	 * The behavior here is to treat addresses on !IFF_UP interface
643	 * as not mine.
644	 */
645	downmatch = 0;
646	LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
647		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
648			if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif)
649				continue;
650			if ((ia->ia_ifp->if_flags & IFF_UP) != 0)
651				break;
652			else
653				downmatch++;
654		}
655	}
656	if (ia != NULL)
657		goto ours;
658	if (m->m_pkthdr.rcvif && m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
659		IFADDR_FOREACH(ifa, m->m_pkthdr.rcvif) {
660			if (ifa->ifa_addr->sa_family != AF_INET)
661				continue;
662			ia = ifatoia(ifa);
663			if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
664			    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
665			    /*
666			     * Look for all-0's host part (old broadcast addr),
667			     * either for subnet or net.
668			     */
669			    ip->ip_dst.s_addr == ia->ia_subnet ||
670			    ip->ip_dst.s_addr == ia->ia_net)
671				goto ours;
672			/*
673			 * An interface with IP address zero accepts
674			 * all packets that arrive on that interface.
675			 */
676			if (in_nullhost(ia->ia_addr.sin_addr))
677				goto ours;
678		}
679	}
680	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
681		struct in_multi *inm;
682#ifdef MROUTING
683		extern struct socket *ip_mrouter;
684
685		if (ip_mrouter) {
686			/*
687			 * If we are acting as a multicast router, all
688			 * incoming multicast packets are passed to the
689			 * kernel-level multicast forwarding function.
690			 * The packet is returned (relatively) intact; if
691			 * ip_mforward() returns a non-zero value, the packet
692			 * must be discarded, else it may be accepted below.
693			 *
694			 * (The IP ident field is put in the same byte order
695			 * as expected when ip_mforward() is called from
696			 * ip_output().)
697			 */
698			if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
699				IP_STATINC(IP_STAT_CANTFORWARD);
700				m_freem(m);
701				return;
702			}
703
704			/*
705			 * The process-level routing demon needs to receive
706			 * all multicast IGMP packets, whether or not this
707			 * host belongs to their destination groups.
708			 */
709			if (ip->ip_p == IPPROTO_IGMP)
710				goto ours;
711			IP_STATINC(IP_STAT_CANTFORWARD);
712		}
713#endif
714		/*
715		 * See if we belong to the destination multicast group on the
716		 * arrival interface.
717		 */
718		IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
719		if (inm == NULL) {
720			IP_STATINC(IP_STAT_CANTFORWARD);
721			m_freem(m);
722			return;
723		}
724		goto ours;
725	}
726	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
727	    in_nullhost(ip->ip_dst))
728		goto ours;
729
730	/*
731	 * Not for us; forward if possible and desirable.
732	 */
733	if (ipforwarding == 0) {
734		IP_STATINC(IP_STAT_CANTFORWARD);
735		m_freem(m);
736	} else {
737		/*
738		 * If ip_dst matched any of my address on !IFF_UP interface,
739		 * and there's no IFF_UP interface that matches ip_dst,
740		 * send icmp unreach.  Forwarding it will result in in-kernel
741		 * forwarding loop till TTL goes to 0.
742		 */
743		if (downmatch) {
744			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
745			IP_STATINC(IP_STAT_CANTFORWARD);
746			return;
747		}
748#ifdef IPSEC
749		if (ipsec4_in_reject(m, NULL)) {
750			IPSEC_STATINC(IPSEC_STAT_IN_POLVIO);
751			goto bad;
752		}
753#endif
754#ifdef FAST_IPSEC
755		mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
756		s = splsoftnet();
757		if (mtag != NULL) {
758			tdbi = (struct tdb_ident *)(mtag + 1);
759			sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
760		} else {
761			sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
762						   IP_FORWARDING, &error);
763		}
764		if (sp == NULL) {	/* NB: can happen if error */
765			splx(s);
766			/*XXX error stat???*/
767			DPRINTF(("ip_input: no SP for forwarding\n"));	/*XXX*/
768			goto bad;
769		}
770
771		/*
772		 * Check security policy against packet attributes.
773		 */
774		error = ipsec_in_reject(sp, m);
775		KEY_FREESP(&sp);
776		splx(s);
777		if (error) {
778			IP_STATINC(IP_STAT_CANTFORWARD);
779			goto bad;
780		}
781
782		/*
783		 * Peek at the outbound SP for this packet to determine if
784		 * it's a Fast Forward candidate.
785		 */
786		mtag = m_tag_find(m, PACKET_TAG_IPSEC_PENDING_TDB, NULL);
787		if (mtag != NULL)
788			m->m_flags &= ~M_CANFASTFWD;
789		else {
790			s = splsoftnet();
791			sp = ipsec4_checkpolicy(m, IPSEC_DIR_OUTBOUND,
792			    (IP_FORWARDING |
793			     (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
794			    &error, NULL);
795			if (sp != NULL) {
796				m->m_flags &= ~M_CANFASTFWD;
797				KEY_FREESP(&sp);
798			}
799			splx(s);
800		}
801#endif	/* FAST_IPSEC */
802
803		ip_forward(m, srcrt);
804	}
805	return;
806
807ours:
808	/*
809	 * If offset or IP_MF are set, must reassemble.
810	 */
811	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
812		struct ipq *fp;
813		u_int off, hash;
814		bool mff;
815
816		/*
817		 * Prevent TCP blind data attacks by not allowing non-initial
818		 * fragments to start at less than 68 bytes (minimal fragment
819		 * size) and making sure the first fragment is at least 68
820		 * bytes.
821		 */
822		off = (ntohs(ip->ip_off) & IP_OFFMASK) << 3;
823		if ((off > 0 ? off + hlen : len) < IP_MINFRAGSIZE - 1) {
824			IP_STATINC(IP_STAT_BADFRAGS);
825			goto bad;
826		}
827
828		/*
829		 * Adjust total IP length to not reflect header.  Set 'mff'
830		 * indicator, if more fragments are expected.  Convert offset
831		 * of this to bytes.
832		 */
833		ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
834		mff = (ip->ip_off & htons(IP_MF)) != 0;
835		if (mff) {
836			/*
837			 * Make sure that fragments have a data length
838			 * which is non-zero and multiple of 8 bytes.
839			 */
840			if (ntohs(ip->ip_len) == 0 ||
841			    (ntohs(ip->ip_len) & 0x7) != 0) {
842				IP_STATINC(IP_STAT_BADFRAGS);
843				goto bad;
844			}
845		}
846		ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3);
847
848		/* Look for queue of fragments of this datagram. */
849		fp = ip_reass_lookup(ip, &hash);
850
851		/* Make sure the TOS matches previous fragments. */
852		if (fp && fp->ipq_tos != ip->ip_tos) {
853			IP_STATINC(IP_STAT_BADFRAGS);
854			ip_reass_unlock();
855			goto bad;
856		}
857
858		/*
859		 * If datagram marked as having more fragments
860		 * or if this is not the first fragment,
861		 * attempt reassembly; if it succeeds, proceed.
862		 */
863		if (mff || ip->ip_off != htons(0)) {
864			struct ipqent *ipqe;
865
866			ipqe = ip_reass_getent();
867			if (ipqe == NULL) {
868				IP_STATINC(IP_STAT_RCVMEMDROP);
869				ip_reass_unlock();
870				goto bad;
871			}
872			ipqe->ipqe_mff = mff;
873			ipqe->ipqe_m = m;
874			ipqe->ipqe_ip = ip;
875			m = ip_reass(ipqe, fp, hash);
876			if (m == NULL) {
877				return;
878			}
879			IP_STATINC(IP_STAT_REASSEMBLED);
880			ip = mtod(m, struct ip *);
881			hlen = ip->ip_hl << 2;
882			ip->ip_len = htons(ntohs(ip->ip_len) + hlen);
883		} else if (fp) {
884			ip_freef(fp);
885			ip_reass_unlock();
886		}
887	}
888
889#if defined(IPSEC)
890	/*
891	 * enforce IPsec policy checking if we are seeing last header.
892	 * note that we do not visit this with protocols with pcb layer
893	 * code - like udp/tcp/raw ip.
894	 */
895	if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
896	    ipsec4_in_reject(m, NULL)) {
897		IPSEC_STATINC(IPSEC_STAT_IN_POLVIO);
898		goto bad;
899	}
900#endif
901#ifdef FAST_IPSEC
902	/*
903	 * enforce IPsec policy checking if we are seeing last header.
904	 * note that we do not visit this with protocols with pcb layer
905	 * code - like udp/tcp/raw ip.
906	 */
907	if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0) {
908		/*
909		 * Check if the packet has already had IPsec processing
910		 * done.  If so, then just pass it along.  This tag gets
911		 * set during AH, ESP, etc. input handling, before the
912		 * packet is returned to the ip input queue for delivery.
913		 */
914		mtag = m_tag_find(m, PACKET_TAG_IPSEC_IN_DONE, NULL);
915		s = splsoftnet();
916		if (mtag != NULL) {
917			tdbi = (struct tdb_ident *)(mtag + 1);
918			sp = ipsec_getpolicy(tdbi, IPSEC_DIR_INBOUND);
919		} else {
920			sp = ipsec_getpolicybyaddr(m, IPSEC_DIR_INBOUND,
921						   IP_FORWARDING, &error);
922		}
923		if (sp != NULL) {
924			/*
925			 * Check security policy against packet attributes.
926			 */
927			error = ipsec_in_reject(sp, m);
928			KEY_FREESP(&sp);
929		} else {
930			/* XXX error stat??? */
931			error = EINVAL;
932DPRINTF(("ip_input: no SP, packet discarded\n"));/*XXX*/
933		}
934		splx(s);
935		if (error)
936			goto bad;
937	}
938#endif /* FAST_IPSEC */
939
940	/*
941	 * Switch out to protocol's input routine.
942	 */
943#if IFA_STATS
944	if (ia && ip)
945		ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
946#endif
947	IP_STATINC(IP_STAT_DELIVERED);
948    {
949	int off = hlen, nh = ip->ip_p;
950
951	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
952	return;
953    }
954bad:
955	m_freem(m);
956	return;
957
958badcsum:
959	IP_STATINC(IP_STAT_BADSUM);
960	m_freem(m);
961}
962
963/*
964 * IP timer processing.
965 */
966void
967ip_slowtimo(void)
968{
969
970	mutex_enter(softnet_lock);
971	KERNEL_LOCK(1, NULL);
972
973	ip_reass_slowtimo();
974
975	KERNEL_UNLOCK_ONE(NULL);
976	mutex_exit(softnet_lock);
977}
978
979/*
980 * IP drain processing.
981 */
982void
983ip_drain(void)
984{
985
986	KERNEL_LOCK(1, NULL);
987	ip_reass_drain();
988	KERNEL_UNLOCK_ONE(NULL);
989}
990
991/*
992 * Do option processing on a datagram,
993 * possibly discarding it if bad options are encountered,
994 * or forwarding it if source-routed.
995 * Returns 1 if packet has been forwarded/freed,
996 * 0 if the packet should be processed further.
997 */
998int
999ip_dooptions(struct mbuf *m)
1000{
1001	struct ip *ip = mtod(m, struct ip *);
1002	u_char *cp, *cp0;
1003	struct ip_timestamp *ipt;
1004	struct in_ifaddr *ia;
1005	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1006	struct in_addr dst;
1007	n_time ntime;
1008
1009	dst = ip->ip_dst;
1010	cp = (u_char *)(ip + 1);
1011	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
1012	for (; cnt > 0; cnt -= optlen, cp += optlen) {
1013		opt = cp[IPOPT_OPTVAL];
1014		if (opt == IPOPT_EOL)
1015			break;
1016		if (opt == IPOPT_NOP)
1017			optlen = 1;
1018		else {
1019			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
1020				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1021				goto bad;
1022			}
1023			optlen = cp[IPOPT_OLEN];
1024			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1025				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1026				goto bad;
1027			}
1028		}
1029		switch (opt) {
1030
1031		default:
1032			break;
1033
1034		/*
1035		 * Source routing with record.
1036		 * Find interface with current destination address.
1037		 * If none on this machine then drop if strictly routed,
1038		 * or do nothing if loosely routed.
1039		 * Record interface address and bring up next address
1040		 * component.  If strictly routed make sure next
1041		 * address is on directly accessible net.
1042		 */
1043		case IPOPT_LSRR:
1044		case IPOPT_SSRR:
1045			if (ip_allowsrcrt == 0) {
1046				type = ICMP_UNREACH;
1047				code = ICMP_UNREACH_NET_PROHIB;
1048				goto bad;
1049			}
1050			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1051				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1052				goto bad;
1053			}
1054			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1055				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1056				goto bad;
1057			}
1058			ipaddr.sin_addr = ip->ip_dst;
1059			ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1060			if (ia == 0) {
1061				if (opt == IPOPT_SSRR) {
1062					type = ICMP_UNREACH;
1063					code = ICMP_UNREACH_SRCFAIL;
1064					goto bad;
1065				}
1066				/*
1067				 * Loose routing, and not at next destination
1068				 * yet; nothing to do except forward.
1069				 */
1070				break;
1071			}
1072			off--;			/* 0 origin */
1073			if ((off + sizeof(struct in_addr)) > optlen) {
1074				/*
1075				 * End of source route.  Should be for us.
1076				 */
1077				save_rte(cp, ip->ip_src);
1078				break;
1079			}
1080			/*
1081			 * locate outgoing interface
1082			 */
1083			memcpy((void *)&ipaddr.sin_addr, (void *)(cp + off),
1084			    sizeof(ipaddr.sin_addr));
1085			if (opt == IPOPT_SSRR)
1086				ia = ifatoia(ifa_ifwithladdr(sintosa(&ipaddr)));
1087			else
1088				ia = ip_rtaddr(ipaddr.sin_addr);
1089			if (ia == 0) {
1090				type = ICMP_UNREACH;
1091				code = ICMP_UNREACH_SRCFAIL;
1092				goto bad;
1093			}
1094			ip->ip_dst = ipaddr.sin_addr;
1095			bcopy((void *)&ia->ia_addr.sin_addr,
1096			    (void *)(cp + off), sizeof(struct in_addr));
1097			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1098			/*
1099			 * Let ip_intr's mcast routing check handle mcast pkts
1100			 */
1101			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1102			break;
1103
1104		case IPOPT_RR:
1105			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1106				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1107				goto bad;
1108			}
1109			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1110				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1111				goto bad;
1112			}
1113			/*
1114			 * If no space remains, ignore.
1115			 */
1116			off--;			/* 0 origin */
1117			if ((off + sizeof(struct in_addr)) > optlen)
1118				break;
1119			memcpy((void *)&ipaddr.sin_addr, (void *)(&ip->ip_dst),
1120			    sizeof(ipaddr.sin_addr));
1121			/*
1122			 * locate outgoing interface; if we're the destination,
1123			 * use the incoming interface (should be same).
1124			 */
1125			if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))))
1126			    == NULL &&
1127			    (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
1128				type = ICMP_UNREACH;
1129				code = ICMP_UNREACH_HOST;
1130				goto bad;
1131			}
1132			bcopy((void *)&ia->ia_addr.sin_addr,
1133			    (void *)(cp + off), sizeof(struct in_addr));
1134			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1135			break;
1136
1137		case IPOPT_TS:
1138			code = cp - (u_char *)ip;
1139			ipt = (struct ip_timestamp *)cp;
1140			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
1141				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
1142				goto bad;
1143			}
1144			if (ipt->ipt_ptr < 5) {
1145				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
1146				goto bad;
1147			}
1148			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1149				if (++ipt->ipt_oflw == 0) {
1150					code = (u_char *)&ipt->ipt_ptr -
1151					    (u_char *)ip;
1152					goto bad;
1153				}
1154				break;
1155			}
1156			cp0 = (cp + ipt->ipt_ptr - 1);
1157			switch (ipt->ipt_flg) {
1158
1159			case IPOPT_TS_TSONLY:
1160				break;
1161
1162			case IPOPT_TS_TSANDADDR:
1163				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1164				    sizeof(struct in_addr) > ipt->ipt_len) {
1165					code = (u_char *)&ipt->ipt_ptr -
1166					    (u_char *)ip;
1167					goto bad;
1168				}
1169				ipaddr.sin_addr = dst;
1170				ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr),
1171				    m->m_pkthdr.rcvif));
1172				if (ia == 0)
1173					continue;
1174				bcopy(&ia->ia_addr.sin_addr,
1175				    cp0, sizeof(struct in_addr));
1176				ipt->ipt_ptr += sizeof(struct in_addr);
1177				break;
1178
1179			case IPOPT_TS_PRESPEC:
1180				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1181				    sizeof(struct in_addr) > ipt->ipt_len) {
1182					code = (u_char *)&ipt->ipt_ptr -
1183					    (u_char *)ip;
1184					goto bad;
1185				}
1186				memcpy(&ipaddr.sin_addr, cp0,
1187				    sizeof(struct in_addr));
1188				if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))
1189				    == NULL)
1190					continue;
1191				ipt->ipt_ptr += sizeof(struct in_addr);
1192				break;
1193
1194			default:
1195				/* XXX can't take &ipt->ipt_flg */
1196				code = (u_char *)&ipt->ipt_ptr -
1197				    (u_char *)ip + 1;
1198				goto bad;
1199			}
1200			ntime = iptime();
1201			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
1202			memmove((char *)cp + ipt->ipt_ptr - 1, cp0,
1203			    sizeof(n_time));
1204			ipt->ipt_ptr += sizeof(n_time);
1205		}
1206	}
1207	if (forward) {
1208		if (ip_forwsrcrt == 0) {
1209			type = ICMP_UNREACH;
1210			code = ICMP_UNREACH_SRCFAIL;
1211			goto bad;
1212		}
1213		ip_forward(m, 1);
1214		return (1);
1215	}
1216	return (0);
1217bad:
1218	icmp_error(m, type, code, 0, 0);
1219	IP_STATINC(IP_STAT_BADOPTIONS);
1220	return (1);
1221}
1222
1223/*
1224 * Given address of next destination (final or next hop),
1225 * return internet address info of interface to be used to get there.
1226 */
1227struct in_ifaddr *
1228ip_rtaddr(struct in_addr dst)
1229{
1230	struct rtentry *rt;
1231	union {
1232		struct sockaddr		dst;
1233		struct sockaddr_in	dst4;
1234	} u;
1235
1236	sockaddr_in_init(&u.dst4, &dst, 0);
1237
1238	if ((rt = rtcache_lookup(&ipforward_rt, &u.dst)) == NULL)
1239		return NULL;
1240
1241	return ifatoia(rt->rt_ifa);
1242}
1243
1244/*
1245 * Save incoming source route for use in replies,
1246 * to be picked up later by ip_srcroute if the receiver is interested.
1247 */
1248void
1249save_rte(u_char *option, struct in_addr dst)
1250{
1251	unsigned olen;
1252
1253	olen = option[IPOPT_OLEN];
1254#ifdef DIAGNOSTIC
1255	if (ipprintfs)
1256		printf("save_rte: olen %d\n", olen);
1257#endif /* 0 */
1258	if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
1259		return;
1260	memcpy((void *)ip_srcrt.srcopt, (void *)option, olen);
1261	ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1262	ip_srcrt.dst = dst;
1263}
1264
1265/*
1266 * Retrieve incoming source route for use in replies,
1267 * in the same form used by setsockopt.
1268 * The first hop is placed before the options, will be removed later.
1269 */
1270struct mbuf *
1271ip_srcroute(void)
1272{
1273	struct in_addr *p, *q;
1274	struct mbuf *m;
1275
1276	if (ip_nhops == 0)
1277		return NULL;
1278	m = m_get(M_DONTWAIT, MT_SOOPTS);
1279	if (m == 0)
1280		return NULL;
1281
1282	MCLAIM(m, &inetdomain.dom_mowner);
1283#define OPTSIZ	(sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1284
1285	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1286	m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
1287	    OPTSIZ;
1288#ifdef DIAGNOSTIC
1289	if (ipprintfs)
1290		printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1291#endif
1292
1293	/*
1294	 * First save first hop for return route
1295	 */
1296	p = &ip_srcrt.route[ip_nhops - 1];
1297	*(mtod(m, struct in_addr *)) = *p--;
1298#ifdef DIAGNOSTIC
1299	if (ipprintfs)
1300		printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1301#endif
1302
1303	/*
1304	 * Copy option fields and padding (nop) to mbuf.
1305	 */
1306	ip_srcrt.nop = IPOPT_NOP;
1307	ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1308	memmove(mtod(m, char *) + sizeof(struct in_addr), &ip_srcrt.nop,
1309	    OPTSIZ);
1310	q = (struct in_addr *)(mtod(m, char *) +
1311	    sizeof(struct in_addr) + OPTSIZ);
1312#undef OPTSIZ
1313	/*
1314	 * Record return path as an IP source route,
1315	 * reversing the path (pointers are now aligned).
1316	 */
1317	while (p >= ip_srcrt.route) {
1318#ifdef DIAGNOSTIC
1319		if (ipprintfs)
1320			printf(" %x", ntohl(q->s_addr));
1321#endif
1322		*q++ = *p--;
1323	}
1324	/*
1325	 * Last hop goes to final destination.
1326	 */
1327	*q = ip_srcrt.dst;
1328#ifdef DIAGNOSTIC
1329	if (ipprintfs)
1330		printf(" %x\n", ntohl(q->s_addr));
1331#endif
1332	return (m);
1333}
1334
1335const int inetctlerrmap[PRC_NCMDS] = {
1336	[PRC_MSGSIZE] = EMSGSIZE,
1337	[PRC_HOSTDEAD] = EHOSTDOWN,
1338	[PRC_HOSTUNREACH] = EHOSTUNREACH,
1339	[PRC_UNREACH_NET] = EHOSTUNREACH,
1340	[PRC_UNREACH_HOST] = EHOSTUNREACH,
1341	[PRC_UNREACH_PROTOCOL] = ECONNREFUSED,
1342	[PRC_UNREACH_PORT] = ECONNREFUSED,
1343	[PRC_UNREACH_SRCFAIL] = EHOSTUNREACH,
1344	[PRC_PARAMPROB] = ENOPROTOOPT,
1345};
1346
1347/*
1348 * Forward a packet.  If some error occurs return the sender
1349 * an icmp packet.  Note we can't always generate a meaningful
1350 * icmp message because icmp doesn't have a large enough repertoire
1351 * of codes and types.
1352 *
1353 * If not forwarding, just drop the packet.  This could be confusing
1354 * if ipforwarding was zero but some routing protocol was advancing
1355 * us as a gateway to somewhere.  However, we must let the routing
1356 * protocol deal with that.
1357 *
1358 * The srcrt parameter indicates whether the packet is being forwarded
1359 * via a source route.
1360 */
1361void
1362ip_forward(struct mbuf *m, int srcrt)
1363{
1364	struct ip *ip = mtod(m, struct ip *);
1365	struct rtentry *rt;
1366	int error, type = 0, code = 0, destmtu = 0;
1367	struct mbuf *mcopy;
1368	n_long dest;
1369	union {
1370		struct sockaddr		dst;
1371		struct sockaddr_in	dst4;
1372	} u;
1373
1374	/*
1375	 * We are now in the output path.
1376	 */
1377	MCLAIM(m, &ip_tx_mowner);
1378
1379	/*
1380	 * Clear any in-bound checksum flags for this packet.
1381	 */
1382	m->m_pkthdr.csum_flags = 0;
1383
1384	dest = 0;
1385#ifdef DIAGNOSTIC
1386	if (ipprintfs) {
1387		printf("forward: src %s ", inet_ntoa(ip->ip_src));
1388		printf("dst %s ttl %x\n", inet_ntoa(ip->ip_dst), ip->ip_ttl);
1389	}
1390#endif
1391	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1392		IP_STATINC(IP_STAT_CANTFORWARD);
1393		m_freem(m);
1394		return;
1395	}
1396	if (ip->ip_ttl <= IPTTLDEC) {
1397		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1398		return;
1399	}
1400
1401	sockaddr_in_init(&u.dst4, &ip->ip_dst, 0);
1402	if ((rt = rtcache_lookup(&ipforward_rt, &u.dst)) == NULL) {
1403		icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_NET, dest, 0);
1404		return;
1405	}
1406
1407	/*
1408	 * Save at most 68 bytes of the packet in case
1409	 * we need to generate an ICMP message to the src.
1410	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
1411	 */
1412	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
1413	if (mcopy)
1414		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
1415
1416	ip->ip_ttl -= IPTTLDEC;
1417
1418	/*
1419	 * If forwarding packet using same interface that it came in on,
1420	 * perhaps should send a redirect to sender to shortcut a hop.
1421	 * Only send redirect if source is sending directly to us,
1422	 * and if packet was not source routed (or has any options).
1423	 * Also, don't send redirect if forwarding using a default route
1424	 * or a route modified by a redirect.
1425	 */
1426	if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1427	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1428	    !in_nullhost(satocsin(rt_getkey(rt))->sin_addr) &&
1429	    ipsendredirects && !srcrt) {
1430		if (rt->rt_ifa &&
1431		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1432		    ifatoia(rt->rt_ifa)->ia_subnet) {
1433			if (rt->rt_flags & RTF_GATEWAY)
1434				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1435			else
1436				dest = ip->ip_dst.s_addr;
1437			/*
1438			 * Router requirements says to only send host
1439			 * redirects.
1440			 */
1441			type = ICMP_REDIRECT;
1442			code = ICMP_REDIRECT_HOST;
1443#ifdef DIAGNOSTIC
1444			if (ipprintfs)
1445				printf("redirect (%d) to %x\n", code,
1446				    (u_int32_t)dest);
1447#endif
1448		}
1449	}
1450
1451	error = ip_output(m, NULL, &ipforward_rt,
1452	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)),
1453	    (struct ip_moptions *)NULL, (struct socket *)NULL);
1454
1455	if (error)
1456		IP_STATINC(IP_STAT_CANTFORWARD);
1457	else {
1458		uint64_t *ips = IP_STAT_GETREF();
1459		ips[IP_STAT_FORWARD]++;
1460		if (type) {
1461			ips[IP_STAT_REDIRECTSENT]++;
1462			IP_STAT_PUTREF();
1463		} else {
1464			IP_STAT_PUTREF();
1465			if (mcopy) {
1466#ifdef GATEWAY
1467				if (mcopy->m_flags & M_CANFASTFWD)
1468					ipflow_create(&ipforward_rt, mcopy);
1469#endif
1470				m_freem(mcopy);
1471			}
1472			return;
1473		}
1474	}
1475	if (mcopy == NULL)
1476		return;
1477
1478	switch (error) {
1479
1480	case 0:				/* forwarded, but need redirect */
1481		/* type, code set above */
1482		break;
1483
1484	case ENETUNREACH:		/* shouldn't happen, checked above */
1485	case EHOSTUNREACH:
1486	case ENETDOWN:
1487	case EHOSTDOWN:
1488	default:
1489		type = ICMP_UNREACH;
1490		code = ICMP_UNREACH_HOST;
1491		break;
1492
1493	case EMSGSIZE:
1494		type = ICMP_UNREACH;
1495		code = ICMP_UNREACH_NEEDFRAG;
1496
1497		if ((rt = rtcache_validate(&ipforward_rt)) != NULL)
1498			destmtu = rt->rt_ifp->if_mtu;
1499
1500#if defined(IPSEC) || defined(FAST_IPSEC)
1501		{
1502			/*
1503			 * If the packet is routed over IPsec tunnel, tell the
1504			 * originator the tunnel MTU.
1505			 *	tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1506			 * XXX quickhack!!!
1507			 */
1508
1509			struct secpolicy *sp;
1510			int ipsecerror;
1511			size_t ipsechdr;
1512			struct route *ro;
1513
1514			sp = ipsec4_getpolicybyaddr(mcopy,
1515			    IPSEC_DIR_OUTBOUND, IP_FORWARDING,
1516			    &ipsecerror);
1517
1518			if (sp != NULL) {
1519				/* count IPsec header size */
1520				ipsechdr = ipsec4_hdrsiz(mcopy,
1521				    IPSEC_DIR_OUTBOUND, NULL);
1522
1523				/*
1524				 * find the correct route for outer IPv4
1525				 * header, compute tunnel MTU.
1526				 */
1527
1528				if (sp->req != NULL
1529				 && sp->req->sav != NULL
1530				 && sp->req->sav->sah != NULL) {
1531					ro = &sp->req->sav->sah->sa_route;
1532					rt = rtcache_validate(ro);
1533					if (rt && rt->rt_ifp) {
1534						destmtu =
1535						    rt->rt_rmx.rmx_mtu ?
1536						    rt->rt_rmx.rmx_mtu :
1537						    rt->rt_ifp->if_mtu;
1538						destmtu -= ipsechdr;
1539					}
1540				}
1541
1542#ifdef	IPSEC
1543				key_freesp(sp);
1544#else
1545				KEY_FREESP(&sp);
1546#endif
1547			}
1548		}
1549#endif /*defined(IPSEC) || defined(FAST_IPSEC)*/
1550		IP_STATINC(IP_STAT_CANTFRAG);
1551		break;
1552
1553	case ENOBUFS:
1554#if 1
1555		/*
1556		 * a router should not generate ICMP_SOURCEQUENCH as
1557		 * required in RFC1812 Requirements for IP Version 4 Routers.
1558		 * source quench could be a big problem under DoS attacks,
1559		 * or if the underlying interface is rate-limited.
1560		 */
1561		if (mcopy)
1562			m_freem(mcopy);
1563		return;
1564#else
1565		type = ICMP_SOURCEQUENCH;
1566		code = 0;
1567		break;
1568#endif
1569	}
1570	icmp_error(mcopy, type, code, dest, destmtu);
1571}
1572
1573void
1574ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
1575    struct mbuf *m)
1576{
1577
1578	if (inp->inp_socket->so_options & SO_TIMESTAMP
1579#ifdef SO_OTIMESTAMP
1580	    || inp->inp_socket->so_options & SO_OTIMESTAMP
1581#endif
1582	    ) {
1583		struct timeval tv;
1584
1585		microtime(&tv);
1586#ifdef SO_OTIMESTAMP
1587		if (inp->inp_socket->so_options & SO_OTIMESTAMP) {
1588			struct timeval50 tv50;
1589			timeval_to_timeval50(&tv, &tv50);
1590			*mp = sbcreatecontrol((void *) &tv50, sizeof(tv50),
1591			    SCM_OTIMESTAMP, SOL_SOCKET);
1592		} else
1593#endif
1594		*mp = sbcreatecontrol((void *) &tv, sizeof(tv),
1595		    SCM_TIMESTAMP, SOL_SOCKET);
1596		if (*mp)
1597			mp = &(*mp)->m_next;
1598	}
1599	if (inp->inp_flags & INP_RECVDSTADDR) {
1600		*mp = sbcreatecontrol((void *) &ip->ip_dst,
1601		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1602		if (*mp)
1603			mp = &(*mp)->m_next;
1604	}
1605#ifdef notyet
1606	/*
1607	 * XXX
1608	 * Moving these out of udp_input() made them even more broken
1609	 * than they already were.
1610	 *	- fenner@parc.xerox.com
1611	 */
1612	/* options were tossed already */
1613	if (inp->inp_flags & INP_RECVOPTS) {
1614		*mp = sbcreatecontrol((void *) opts_deleted_above,
1615		    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1616		if (*mp)
1617			mp = &(*mp)->m_next;
1618	}
1619	/* ip_srcroute doesn't do what we want here, need to fix */
1620	if (inp->inp_flags & INP_RECVRETOPTS) {
1621		*mp = sbcreatecontrol((void *) ip_srcroute(),
1622		    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1623		if (*mp)
1624			mp = &(*mp)->m_next;
1625	}
1626#endif
1627	if (inp->inp_flags & INP_RECVIF) {
1628		struct sockaddr_dl sdl;
1629
1630		sockaddr_dl_init(&sdl, sizeof(sdl),
1631		    (m->m_pkthdr.rcvif != NULL)
1632		        ?  m->m_pkthdr.rcvif->if_index
1633			: 0,
1634			0, NULL, 0, NULL, 0);
1635		*mp = sbcreatecontrol(&sdl, sdl.sdl_len, IP_RECVIF, IPPROTO_IP);
1636		if (*mp)
1637			mp = &(*mp)->m_next;
1638	}
1639	if (inp->inp_flags & INP_RECVTTL) {
1640		*mp = sbcreatecontrol((void *) &ip->ip_ttl,
1641		    sizeof(uint8_t), IP_RECVTTL, IPPROTO_IP);
1642		if (*mp)
1643			mp = &(*mp)->m_next;
1644	}
1645}
1646
1647/*
1648 * sysctl helper routine for net.inet.ip.forwsrcrt.
1649 */
1650static int
1651sysctl_net_inet_ip_forwsrcrt(SYSCTLFN_ARGS)
1652{
1653	int error, tmp;
1654	struct sysctlnode node;
1655
1656	node = *rnode;
1657	tmp = ip_forwsrcrt;
1658	node.sysctl_data = &tmp;
1659	error = sysctl_lookup(SYSCTLFN_CALL(&node));
1660	if (error || newp == NULL)
1661		return (error);
1662
1663	error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_FORWSRCRT,
1664	    0, NULL, NULL, NULL);
1665	if (error)
1666		return (error);
1667
1668	ip_forwsrcrt = tmp;
1669
1670	return (0);
1671}
1672
1673/*
1674 * sysctl helper routine for net.inet.ip.mtudisctimeout.  checks the
1675 * range of the new value and tweaks timers if it changes.
1676 */
1677static int
1678sysctl_net_inet_ip_pmtudto(SYSCTLFN_ARGS)
1679{
1680	int error, tmp;
1681	struct sysctlnode node;
1682
1683	node = *rnode;
1684	tmp = ip_mtudisc_timeout;
1685	node.sysctl_data = &tmp;
1686	error = sysctl_lookup(SYSCTLFN_CALL(&node));
1687	if (error || newp == NULL)
1688		return (error);
1689	if (tmp < 0)
1690		return (EINVAL);
1691
1692	mutex_enter(softnet_lock);
1693
1694	ip_mtudisc_timeout = tmp;
1695	rt_timer_queue_change(ip_mtudisc_timeout_q, ip_mtudisc_timeout);
1696
1697	mutex_exit(softnet_lock);
1698
1699	return (0);
1700}
1701
1702#ifdef GATEWAY
1703/*
1704 * sysctl helper routine for net.inet.ip.maxflows.
1705 */
1706static int
1707sysctl_net_inet_ip_maxflows(SYSCTLFN_ARGS)
1708{
1709	int error;
1710
1711	error = sysctl_lookup(SYSCTLFN_CALL(rnode));
1712	if (error || newp == NULL)
1713		return (error);
1714
1715	mutex_enter(softnet_lock);
1716	KERNEL_LOCK(1, NULL);
1717
1718	ipflow_prune();
1719
1720	KERNEL_UNLOCK_ONE(NULL);
1721	mutex_exit(softnet_lock);
1722
1723	return (0);
1724}
1725
1726static int
1727sysctl_net_inet_ip_hashsize(SYSCTLFN_ARGS)
1728{
1729	int error, tmp;
1730	struct sysctlnode node;
1731
1732	node = *rnode;
1733	tmp = ip_hashsize;
1734	node.sysctl_data = &tmp;
1735	error = sysctl_lookup(SYSCTLFN_CALL(&node));
1736	if (error || newp == NULL)
1737		return (error);
1738
1739	if ((tmp & (tmp - 1)) == 0 && tmp != 0) {
1740		/*
1741		 * Can only fail due to malloc()
1742		 */
1743		mutex_enter(softnet_lock);
1744		KERNEL_LOCK(1, NULL);
1745
1746		error = ipflow_invalidate_all(tmp);
1747
1748		KERNEL_UNLOCK_ONE(NULL);
1749		mutex_exit(softnet_lock);
1750
1751	} else {
1752		/*
1753		 * EINVAL if not a power of 2
1754	         */
1755		error = EINVAL;
1756	}
1757
1758	return error;
1759}
1760#endif /* GATEWAY */
1761
1762static int
1763sysctl_net_inet_ip_stats(SYSCTLFN_ARGS)
1764{
1765
1766	return (NETSTAT_SYSCTL(ipstat_percpu, IP_NSTATS));
1767}
1768
1769static void
1770sysctl_net_inet_ip_setup(struct sysctllog **clog)
1771{
1772	extern int subnetsarelocal, hostzeroisbroadcast;
1773
1774	sysctl_createv(clog, 0, NULL, NULL,
1775		       CTLFLAG_PERMANENT,
1776		       CTLTYPE_NODE, "net", NULL,
1777		       NULL, 0, NULL, 0,
1778		       CTL_NET, CTL_EOL);
1779	sysctl_createv(clog, 0, NULL, NULL,
1780		       CTLFLAG_PERMANENT,
1781		       CTLTYPE_NODE, "inet",
1782		       SYSCTL_DESCR("PF_INET related settings"),
1783		       NULL, 0, NULL, 0,
1784		       CTL_NET, PF_INET, CTL_EOL);
1785	sysctl_createv(clog, 0, NULL, NULL,
1786		       CTLFLAG_PERMANENT,
1787		       CTLTYPE_NODE, "ip",
1788		       SYSCTL_DESCR("IPv4 related settings"),
1789		       NULL, 0, NULL, 0,
1790		       CTL_NET, PF_INET, IPPROTO_IP, CTL_EOL);
1791
1792	sysctl_createv(clog, 0, NULL, NULL,
1793		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1794		       CTLTYPE_INT, "forwarding",
1795		       SYSCTL_DESCR("Enable forwarding of INET datagrams"),
1796		       NULL, 0, &ipforwarding, 0,
1797		       CTL_NET, PF_INET, IPPROTO_IP,
1798		       IPCTL_FORWARDING, CTL_EOL);
1799	sysctl_createv(clog, 0, NULL, NULL,
1800		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1801		       CTLTYPE_INT, "redirect",
1802		       SYSCTL_DESCR("Enable sending of ICMP redirect messages"),
1803		       NULL, 0, &ipsendredirects, 0,
1804		       CTL_NET, PF_INET, IPPROTO_IP,
1805		       IPCTL_SENDREDIRECTS, CTL_EOL);
1806	sysctl_createv(clog, 0, NULL, NULL,
1807		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1808		       CTLTYPE_INT, "ttl",
1809		       SYSCTL_DESCR("Default TTL for an INET datagram"),
1810		       NULL, 0, &ip_defttl, 0,
1811		       CTL_NET, PF_INET, IPPROTO_IP,
1812		       IPCTL_DEFTTL, CTL_EOL);
1813#ifdef IPCTL_DEFMTU
1814	sysctl_createv(clog, 0, NULL, NULL,
1815		       CTLFLAG_PERMANENT /* |CTLFLAG_READWRITE? */,
1816		       CTLTYPE_INT, "mtu",
1817		       SYSCTL_DESCR("Default MTA for an INET route"),
1818		       NULL, 0, &ip_mtu, 0,
1819		       CTL_NET, PF_INET, IPPROTO_IP,
1820		       IPCTL_DEFMTU, CTL_EOL);
1821#endif /* IPCTL_DEFMTU */
1822	sysctl_createv(clog, 0, NULL, NULL,
1823		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1824		       CTLTYPE_INT, "forwsrcrt",
1825		       SYSCTL_DESCR("Enable forwarding of source-routed "
1826				    "datagrams"),
1827		       sysctl_net_inet_ip_forwsrcrt, 0, &ip_forwsrcrt, 0,
1828		       CTL_NET, PF_INET, IPPROTO_IP,
1829		       IPCTL_FORWSRCRT, CTL_EOL);
1830	sysctl_createv(clog, 0, NULL, NULL,
1831		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1832		       CTLTYPE_INT, "directed-broadcast",
1833		       SYSCTL_DESCR("Enable forwarding of broadcast datagrams"),
1834		       NULL, 0, &ip_directedbcast, 0,
1835		       CTL_NET, PF_INET, IPPROTO_IP,
1836		       IPCTL_DIRECTEDBCAST, CTL_EOL);
1837	sysctl_createv(clog, 0, NULL, NULL,
1838		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1839		       CTLTYPE_INT, "allowsrcrt",
1840		       SYSCTL_DESCR("Accept source-routed datagrams"),
1841		       NULL, 0, &ip_allowsrcrt, 0,
1842		       CTL_NET, PF_INET, IPPROTO_IP,
1843		       IPCTL_ALLOWSRCRT, CTL_EOL);
1844	sysctl_createv(clog, 0, NULL, NULL,
1845		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1846		       CTLTYPE_INT, "subnetsarelocal",
1847		       SYSCTL_DESCR("Whether logical subnets are considered "
1848				    "local"),
1849		       NULL, 0, &subnetsarelocal, 0,
1850		       CTL_NET, PF_INET, IPPROTO_IP,
1851		       IPCTL_SUBNETSARELOCAL, CTL_EOL);
1852	sysctl_createv(clog, 0, NULL, NULL,
1853		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1854		       CTLTYPE_INT, "mtudisc",
1855		       SYSCTL_DESCR("Use RFC1191 Path MTU Discovery"),
1856		       NULL, 0, &ip_mtudisc, 0,
1857		       CTL_NET, PF_INET, IPPROTO_IP,
1858		       IPCTL_MTUDISC, CTL_EOL);
1859	sysctl_createv(clog, 0, NULL, NULL,
1860		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1861		       CTLTYPE_INT, "anonportmin",
1862		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
1863		       sysctl_net_inet_ip_ports, 0, &anonportmin, 0,
1864		       CTL_NET, PF_INET, IPPROTO_IP,
1865		       IPCTL_ANONPORTMIN, CTL_EOL);
1866	sysctl_createv(clog, 0, NULL, NULL,
1867		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1868		       CTLTYPE_INT, "anonportmax",
1869		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
1870		       sysctl_net_inet_ip_ports, 0, &anonportmax, 0,
1871		       CTL_NET, PF_INET, IPPROTO_IP,
1872		       IPCTL_ANONPORTMAX, CTL_EOL);
1873	sysctl_createv(clog, 0, NULL, NULL,
1874		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1875		       CTLTYPE_INT, "mtudisctimeout",
1876		       SYSCTL_DESCR("Lifetime of a Path MTU Discovered route"),
1877		       sysctl_net_inet_ip_pmtudto, 0, &ip_mtudisc_timeout, 0,
1878		       CTL_NET, PF_INET, IPPROTO_IP,
1879		       IPCTL_MTUDISCTIMEOUT, CTL_EOL);
1880#ifdef GATEWAY
1881	sysctl_createv(clog, 0, NULL, NULL,
1882		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1883		       CTLTYPE_INT, "maxflows",
1884		       SYSCTL_DESCR("Number of flows for fast forwarding"),
1885		       sysctl_net_inet_ip_maxflows, 0, &ip_maxflows, 0,
1886		       CTL_NET, PF_INET, IPPROTO_IP,
1887		       IPCTL_MAXFLOWS, CTL_EOL);
1888	sysctl_createv(clog, 0, NULL, NULL,
1889			CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1890			CTLTYPE_INT, "hashsize",
1891			SYSCTL_DESCR("Size of hash table for fast forwarding (IPv4)"),
1892			sysctl_net_inet_ip_hashsize, 0, &ip_hashsize, 0,
1893			CTL_NET, PF_INET, IPPROTO_IP,
1894			CTL_CREATE, CTL_EOL);
1895#endif /* GATEWAY */
1896	sysctl_createv(clog, 0, NULL, NULL,
1897		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1898		       CTLTYPE_INT, "hostzerobroadcast",
1899		       SYSCTL_DESCR("All zeroes address is broadcast address"),
1900		       NULL, 0, &hostzeroisbroadcast, 0,
1901		       CTL_NET, PF_INET, IPPROTO_IP,
1902		       IPCTL_HOSTZEROBROADCAST, CTL_EOL);
1903#if NGIF > 0
1904	sysctl_createv(clog, 0, NULL, NULL,
1905		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1906		       CTLTYPE_INT, "gifttl",
1907		       SYSCTL_DESCR("Default TTL for a gif tunnel datagram"),
1908		       NULL, 0, &ip_gif_ttl, 0,
1909		       CTL_NET, PF_INET, IPPROTO_IP,
1910		       IPCTL_GIF_TTL, CTL_EOL);
1911#endif /* NGIF */
1912#ifndef IPNOPRIVPORTS
1913	sysctl_createv(clog, 0, NULL, NULL,
1914		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1915		       CTLTYPE_INT, "lowportmin",
1916		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
1917				    "to assign"),
1918		       sysctl_net_inet_ip_ports, 0, &lowportmin, 0,
1919		       CTL_NET, PF_INET, IPPROTO_IP,
1920		       IPCTL_LOWPORTMIN, CTL_EOL);
1921	sysctl_createv(clog, 0, NULL, NULL,
1922		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1923		       CTLTYPE_INT, "lowportmax",
1924		       SYSCTL_DESCR("Highest privileged ephemeral port number "
1925				    "to assign"),
1926		       sysctl_net_inet_ip_ports, 0, &lowportmax, 0,
1927		       CTL_NET, PF_INET, IPPROTO_IP,
1928		       IPCTL_LOWPORTMAX, CTL_EOL);
1929#endif /* IPNOPRIVPORTS */
1930#if NGRE > 0
1931	sysctl_createv(clog, 0, NULL, NULL,
1932		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1933		       CTLTYPE_INT, "grettl",
1934		       SYSCTL_DESCR("Default TTL for a gre tunnel datagram"),
1935		       NULL, 0, &ip_gre_ttl, 0,
1936		       CTL_NET, PF_INET, IPPROTO_IP,
1937		       IPCTL_GRE_TTL, CTL_EOL);
1938#endif /* NGRE */
1939	sysctl_createv(clog, 0, NULL, NULL,
1940		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1941		       CTLTYPE_INT, "checkinterface",
1942		       SYSCTL_DESCR("Enable receive side of Strong ES model "
1943				    "from RFC1122"),
1944		       NULL, 0, &ip_checkinterface, 0,
1945		       CTL_NET, PF_INET, IPPROTO_IP,
1946		       IPCTL_CHECKINTERFACE, CTL_EOL);
1947	sysctl_createv(clog, 0, NULL, NULL,
1948		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1949		       CTLTYPE_INT, "random_id",
1950		       SYSCTL_DESCR("Assign random ip_id values"),
1951		       NULL, 0, &ip_do_randomid, 0,
1952		       CTL_NET, PF_INET, IPPROTO_IP,
1953		       IPCTL_RANDOMID, CTL_EOL);
1954	sysctl_createv(clog, 0, NULL, NULL,
1955		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
1956		       CTLTYPE_INT, "do_loopback_cksum",
1957		       SYSCTL_DESCR("Perform IP checksum on loopback"),
1958		       NULL, 0, &ip_do_loopback_cksum, 0,
1959		       CTL_NET, PF_INET, IPPROTO_IP,
1960		       IPCTL_LOOPBACKCKSUM, CTL_EOL);
1961	sysctl_createv(clog, 0, NULL, NULL,
1962		       CTLFLAG_PERMANENT,
1963		       CTLTYPE_STRUCT, "stats",
1964		       SYSCTL_DESCR("IP statistics"),
1965		       sysctl_net_inet_ip_stats, 0, NULL, 0,
1966		       CTL_NET, PF_INET, IPPROTO_IP, IPCTL_STATS,
1967		       CTL_EOL);
1968}
1969
1970void
1971ip_statinc(u_int stat)
1972{
1973
1974	KASSERT(stat < IP_NSTATS);
1975	IP_STATINC(stat);
1976}
1977