ip_input.c revision 1.172
1/*	$NetBSD: ip_input.c,v 1.172 2003/08/07 16:33:12 agc 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 * 3. All advertising materials mentioning features or use of this software
49 *    must display the following acknowledgement:
50 *	This product includes software developed by the NetBSD
51 *	Foundation, Inc. and its contributors.
52 * 4. Neither the name of The NetBSD Foundation nor the names of its
53 *    contributors may be used to endorse or promote products derived
54 *    from this software without specific prior written permission.
55 *
56 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
57 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
58 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
59 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
60 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
61 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
62 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
63 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
64 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
65 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
66 * POSSIBILITY OF SUCH DAMAGE.
67 */
68
69/*
70 * Copyright (c) 1982, 1986, 1988, 1993
71 *	The Regents of the University of California.  All rights reserved.
72 *
73 * Redistribution and use in source and binary forms, with or without
74 * modification, are permitted provided that the following conditions
75 * are met:
76 * 1. Redistributions of source code must retain the above copyright
77 *    notice, this list of conditions and the following disclaimer.
78 * 2. Redistributions in binary form must reproduce the above copyright
79 *    notice, this list of conditions and the following disclaimer in the
80 *    documentation and/or other materials provided with the distribution.
81 * 3. Neither the name of the University nor the names of its contributors
82 *    may be used to endorse or promote products derived from this software
83 *    without specific prior written permission.
84 *
85 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
86 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
87 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
88 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
89 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
90 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
91 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
92 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
93 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
94 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
95 * SUCH DAMAGE.
96 *
97 *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
98 */
99
100#include <sys/cdefs.h>
101__KERNEL_RCSID(0, "$NetBSD: ip_input.c,v 1.172 2003/08/07 16:33:12 agc Exp $");
102
103#include "opt_gateway.h"
104#include "opt_pfil_hooks.h"
105#include "opt_ipsec.h"
106#include "opt_mrouting.h"
107#include "opt_mbuftrace.h"
108#include "opt_inet_csum.h"
109
110#include <sys/param.h>
111#include <sys/systm.h>
112#include <sys/malloc.h>
113#include <sys/mbuf.h>
114#include <sys/domain.h>
115#include <sys/protosw.h>
116#include <sys/socket.h>
117#include <sys/socketvar.h>
118#include <sys/errno.h>
119#include <sys/time.h>
120#include <sys/kernel.h>
121#include <sys/pool.h>
122#include <sys/sysctl.h>
123
124#include <net/if.h>
125#include <net/if_dl.h>
126#include <net/route.h>
127#include <net/pfil.h>
128
129#include <netinet/in.h>
130#include <netinet/in_systm.h>
131#include <netinet/ip.h>
132#include <netinet/in_pcb.h>
133#include <netinet/in_var.h>
134#include <netinet/ip_var.h>
135#include <netinet/ip_icmp.h>
136/* just for gif_ttl */
137#include <netinet/in_gif.h>
138#include "gif.h"
139#include <net/if_gre.h>
140#include "gre.h"
141
142#ifdef MROUTING
143#include <netinet/ip_mroute.h>
144#endif
145
146#ifdef IPSEC
147#include <netinet6/ipsec.h>
148#include <netkey/key.h>
149#endif
150
151#ifndef	IPFORWARDING
152#ifdef GATEWAY
153#define	IPFORWARDING	1	/* forward IP packets not for us */
154#else /* GATEWAY */
155#define	IPFORWARDING	0	/* don't forward IP packets not for us */
156#endif /* GATEWAY */
157#endif /* IPFORWARDING */
158#ifndef	IPSENDREDIRECTS
159#define	IPSENDREDIRECTS	1
160#endif
161#ifndef IPFORWSRCRT
162#define	IPFORWSRCRT	1	/* forward source-routed packets */
163#endif
164#ifndef IPALLOWSRCRT
165#define	IPALLOWSRCRT	1	/* allow source-routed packets */
166#endif
167#ifndef IPMTUDISC
168#define IPMTUDISC	1
169#endif
170#ifndef IPMTUDISCTIMEOUT
171#define IPMTUDISCTIMEOUT (10 * 60)	/* as per RFC 1191 */
172#endif
173
174/*
175 * Note: DIRECTED_BROADCAST is handled this way so that previous
176 * configuration using this option will Just Work.
177 */
178#ifndef IPDIRECTEDBCAST
179#ifdef DIRECTED_BROADCAST
180#define IPDIRECTEDBCAST	1
181#else
182#define	IPDIRECTEDBCAST	0
183#endif /* DIRECTED_BROADCAST */
184#endif /* IPDIRECTEDBCAST */
185int	ipforwarding = IPFORWARDING;
186int	ipsendredirects = IPSENDREDIRECTS;
187int	ip_defttl = IPDEFTTL;
188int	ip_forwsrcrt = IPFORWSRCRT;
189int	ip_directedbcast = IPDIRECTEDBCAST;
190int	ip_allowsrcrt = IPALLOWSRCRT;
191int	ip_mtudisc = IPMTUDISC;
192int	ip_mtudisc_timeout = IPMTUDISCTIMEOUT;
193#ifdef DIAGNOSTIC
194int	ipprintfs = 0;
195#endif
196/*
197 * XXX - Setting ip_checkinterface mostly implements the receive side of
198 * the Strong ES model described in RFC 1122, but since the routing table
199 * and transmit implementation do not implement the Strong ES model,
200 * setting this to 1 results in an odd hybrid.
201 *
202 * XXX - ip_checkinterface currently must be disabled if you use ipnat
203 * to translate the destination address to another local interface.
204 *
205 * XXX - ip_checkinterface must be disabled if you add IP aliases
206 * to the loopback interface instead of the interface where the
207 * packets for those addresses are received.
208 */
209int	ip_checkinterface = 0;
210
211
212struct rttimer_queue *ip_mtudisc_timeout_q = NULL;
213
214extern	struct domain inetdomain;
215int	ipqmaxlen = IFQ_MAXLEN;
216u_long	in_ifaddrhash;				/* size of hash table - 1 */
217int	in_ifaddrentries;			/* total number of addrs */
218struct	in_ifaddrhead in_ifaddr;
219struct	in_ifaddrhashhead *in_ifaddrhashtbl;
220u_long	in_multihash;				/* size of hash table - 1 */
221int	in_multientries;			/* total number of addrs */
222struct	in_multihashhead *in_multihashtbl;
223struct	ifqueue ipintrq;
224struct	ipstat	ipstat;
225u_int16_t	ip_id;
226
227#ifdef PFIL_HOOKS
228struct pfil_head inet_pfil_hook;
229#endif
230
231struct ipqhead ipq;
232int	ipq_locked;
233int	ip_nfragpackets = 0;
234int	ip_maxfragpackets = 200;
235
236static __inline int ipq_lock_try __P((void));
237static __inline void ipq_unlock __P((void));
238
239static __inline int
240ipq_lock_try()
241{
242	int s;
243
244	/*
245	 * Use splvm() -- we're blocking things that would cause
246	 * mbuf allocation.
247	 */
248	s = splvm();
249	if (ipq_locked) {
250		splx(s);
251		return (0);
252	}
253	ipq_locked = 1;
254	splx(s);
255	return (1);
256}
257
258static __inline void
259ipq_unlock()
260{
261	int s;
262
263	s = splvm();
264	ipq_locked = 0;
265	splx(s);
266}
267
268#ifdef DIAGNOSTIC
269#define	IPQ_LOCK()							\
270do {									\
271	if (ipq_lock_try() == 0) {					\
272		printf("%s:%d: ipq already locked\n", __FILE__, __LINE__); \
273		panic("ipq_lock");					\
274	}								\
275} while (/*CONSTCOND*/ 0)
276#define	IPQ_LOCK_CHECK()						\
277do {									\
278	if (ipq_locked == 0) {						\
279		printf("%s:%d: ipq lock not held\n", __FILE__, __LINE__); \
280		panic("ipq lock check");				\
281	}								\
282} while (/*CONSTCOND*/ 0)
283#else
284#define	IPQ_LOCK()		(void) ipq_lock_try()
285#define	IPQ_LOCK_CHECK()	/* nothing */
286#endif
287
288#define	IPQ_UNLOCK()		ipq_unlock()
289
290struct pool inmulti_pool;
291struct pool ipqent_pool;
292
293#ifdef INET_CSUM_COUNTERS
294#include <sys/device.h>
295
296struct evcnt ip_hwcsum_bad = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
297    NULL, "inet", "hwcsum bad");
298struct evcnt ip_hwcsum_ok = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
299    NULL, "inet", "hwcsum ok");
300struct evcnt ip_swcsum = EVCNT_INITIALIZER(EVCNT_TYPE_MISC,
301    NULL, "inet", "swcsum");
302
303#define	INET_CSUM_COUNTER_INCR(ev)	(ev)->ev_count++
304
305#else
306
307#define	INET_CSUM_COUNTER_INCR(ev)	/* nothing */
308
309#endif /* INET_CSUM_COUNTERS */
310
311/*
312 * We need to save the IP options in case a protocol wants to respond
313 * to an incoming packet over the same route if the packet got here
314 * using IP source routing.  This allows connection establishment and
315 * maintenance when the remote end is on a network that is not known
316 * to us.
317 */
318int	ip_nhops = 0;
319static	struct ip_srcrt {
320	struct	in_addr dst;			/* final destination */
321	char	nop;				/* one NOP to align */
322	char	srcopt[IPOPT_OFFSET + 1];	/* OPTVAL, OLEN and OFFSET */
323	struct	in_addr route[MAX_IPOPTLEN/sizeof(struct in_addr)];
324} ip_srcrt;
325
326static void save_rte __P((u_char *, struct in_addr));
327
328#ifdef MBUFTRACE
329struct mowner ip_rx_mowner = { "internet", "rx" };
330struct mowner ip_tx_mowner = { "internet", "tx" };
331#endif
332
333/*
334 * IP initialization: fill in IP protocol switch table.
335 * All protocols not implemented in kernel go to raw IP protocol handler.
336 */
337void
338ip_init()
339{
340	struct protosw *pr;
341	int i;
342
343	pool_init(&inmulti_pool, sizeof(struct in_multi), 0, 0, 0, "inmltpl",
344	    NULL);
345	pool_init(&ipqent_pool, sizeof(struct ipqent), 0, 0, 0, "ipqepl",
346	    NULL);
347
348	pr = pffindproto(PF_INET, IPPROTO_RAW, SOCK_RAW);
349	if (pr == 0)
350		panic("ip_init");
351	for (i = 0; i < IPPROTO_MAX; i++)
352		ip_protox[i] = pr - inetsw;
353	for (pr = inetdomain.dom_protosw;
354	    pr < inetdomain.dom_protoswNPROTOSW; pr++)
355		if (pr->pr_domain->dom_family == PF_INET &&
356		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
357			ip_protox[pr->pr_protocol] = pr - inetsw;
358	LIST_INIT(&ipq);
359	ip_id = time.tv_sec & 0xffff;
360	ipintrq.ifq_maxlen = ipqmaxlen;
361	TAILQ_INIT(&in_ifaddr);
362	in_ifaddrhashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IFADDR,
363	    M_WAITOK, &in_ifaddrhash);
364	in_multihashtbl = hashinit(IN_IFADDR_HASH_SIZE, HASH_LIST, M_IPMADDR,
365	    M_WAITOK, &in_multihash);
366	ip_mtudisc_timeout_q = rt_timer_queue_create(ip_mtudisc_timeout);
367#ifdef GATEWAY
368	ipflow_init();
369#endif
370
371#ifdef PFIL_HOOKS
372	/* Register our Packet Filter hook. */
373	inet_pfil_hook.ph_type = PFIL_TYPE_AF;
374	inet_pfil_hook.ph_af   = AF_INET;
375	i = pfil_head_register(&inet_pfil_hook);
376	if (i != 0)
377		printf("ip_init: WARNING: unable to register pfil hook, "
378		    "error %d\n", i);
379#endif /* PFIL_HOOKS */
380
381#ifdef INET_CSUM_COUNTERS
382	evcnt_attach_static(&ip_hwcsum_bad);
383	evcnt_attach_static(&ip_hwcsum_ok);
384	evcnt_attach_static(&ip_swcsum);
385#endif /* INET_CSUM_COUNTERS */
386
387#ifdef MBUFTRACE
388	MOWNER_ATTACH(&ip_tx_mowner);
389	MOWNER_ATTACH(&ip_rx_mowner);
390#endif /* MBUFTRACE */
391}
392
393struct	sockaddr_in ipaddr = { sizeof(ipaddr), AF_INET };
394struct	route ipforward_rt;
395
396/*
397 * IP software interrupt routine
398 */
399void
400ipintr()
401{
402	int s;
403	struct mbuf *m;
404
405	while (1) {
406		s = splnet();
407		IF_DEQUEUE(&ipintrq, m);
408		splx(s);
409		if (m == 0)
410			return;
411		MCLAIM(m, &ip_rx_mowner);
412		ip_input(m);
413	}
414}
415
416/*
417 * Ip input routine.  Checksum and byte swap header.  If fragmented
418 * try to reassemble.  Process options.  Pass to next level.
419 */
420void
421ip_input(struct mbuf *m)
422{
423	struct ip *ip = NULL;
424	struct ipq *fp;
425	struct in_ifaddr *ia;
426	struct ifaddr *ifa;
427	struct ipqent *ipqe;
428	int hlen = 0, mff, len;
429	int downmatch;
430	int checkif;
431	int srcrt = 0;
432
433	MCLAIM(m, &ip_rx_mowner);
434#ifdef	DIAGNOSTIC
435	if ((m->m_flags & M_PKTHDR) == 0)
436		panic("ipintr no HDR");
437#endif
438#ifdef IPSEC
439	/*
440	 * should the inner packet be considered authentic?
441	 * see comment in ah4_input().
442	 */
443	if (m) {
444		m->m_flags &= ~M_AUTHIPHDR;
445		m->m_flags &= ~M_AUTHIPDGM;
446	}
447#endif
448
449	/*
450	 * If no IP addresses have been set yet but the interfaces
451	 * are receiving, can't do anything with incoming packets yet.
452	 */
453	if (TAILQ_FIRST(&in_ifaddr) == 0)
454		goto bad;
455	ipstat.ips_total++;
456	/*
457	 * If the IP header is not aligned, slurp it up into a new
458	 * mbuf with space for link headers, in the event we forward
459	 * it.  Otherwise, if it is aligned, make sure the entire
460	 * base IP header is in the first mbuf of the chain.
461	 */
462	if (IP_HDR_ALIGNED_P(mtod(m, caddr_t)) == 0) {
463		if ((m = m_copyup(m, sizeof(struct ip),
464				  (max_linkhdr + 3) & ~3)) == NULL) {
465			/* XXXJRT new stat, please */
466			ipstat.ips_toosmall++;
467			return;
468		}
469	} else if (__predict_false(m->m_len < sizeof (struct ip))) {
470		if ((m = m_pullup(m, sizeof (struct ip))) == NULL) {
471			ipstat.ips_toosmall++;
472			return;
473		}
474	}
475	ip = mtod(m, struct ip *);
476	if (ip->ip_v != IPVERSION) {
477		ipstat.ips_badvers++;
478		goto bad;
479	}
480	hlen = ip->ip_hl << 2;
481	if (hlen < sizeof(struct ip)) {	/* minimum header length */
482		ipstat.ips_badhlen++;
483		goto bad;
484	}
485	if (hlen > m->m_len) {
486		if ((m = m_pullup(m, hlen)) == 0) {
487			ipstat.ips_badhlen++;
488			return;
489		}
490		ip = mtod(m, struct ip *);
491	}
492
493	/*
494	 * RFC1122: packets with a multicast source address are
495	 * not allowed.
496	 */
497	if (IN_MULTICAST(ip->ip_src.s_addr)) {
498		ipstat.ips_badaddr++;
499		goto bad;
500	}
501
502	/* 127/8 must not appear on wire - RFC1122 */
503	if ((ntohl(ip->ip_dst.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET ||
504	    (ntohl(ip->ip_src.s_addr) >> IN_CLASSA_NSHIFT) == IN_LOOPBACKNET) {
505		if ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0) {
506			ipstat.ips_badaddr++;
507			goto bad;
508		}
509	}
510
511	switch (m->m_pkthdr.csum_flags &
512		((m->m_pkthdr.rcvif->if_csum_flags_rx & M_CSUM_IPv4) |
513		 M_CSUM_IPv4_BAD)) {
514	case M_CSUM_IPv4|M_CSUM_IPv4_BAD:
515		INET_CSUM_COUNTER_INCR(&ip_hwcsum_bad);
516		goto badcsum;
517
518	case M_CSUM_IPv4:
519		/* Checksum was okay. */
520		INET_CSUM_COUNTER_INCR(&ip_hwcsum_ok);
521		break;
522
523	default:
524		/* Must compute it ourselves. */
525		INET_CSUM_COUNTER_INCR(&ip_swcsum);
526		if (in_cksum(m, hlen) != 0)
527			goto bad;
528		break;
529	}
530
531	/* Retrieve the packet length. */
532	len = ntohs(ip->ip_len);
533
534	/*
535	 * Check for additional length bogosity
536	 */
537	if (len < hlen) {
538	 	ipstat.ips_badlen++;
539		goto bad;
540	}
541
542	/*
543	 * Check that the amount of data in the buffers
544	 * is as at least much as the IP header would have us expect.
545	 * Trim mbufs if longer than we expect.
546	 * Drop packet if shorter than we expect.
547	 */
548	if (m->m_pkthdr.len < len) {
549		ipstat.ips_tooshort++;
550		goto bad;
551	}
552	if (m->m_pkthdr.len > len) {
553		if (m->m_len == m->m_pkthdr.len) {
554			m->m_len = len;
555			m->m_pkthdr.len = len;
556		} else
557			m_adj(m, len - m->m_pkthdr.len);
558	}
559
560#ifdef IPSEC
561	/* ipflow (IP fast forwarding) is not compatible with IPsec. */
562	m->m_flags &= ~M_CANFASTFWD;
563#else
564	/*
565	 * Assume that we can create a fast-forward IP flow entry
566	 * based on this packet.
567	 */
568	m->m_flags |= M_CANFASTFWD;
569#endif
570
571#ifdef PFIL_HOOKS
572	/*
573	 * Run through list of hooks for input packets.  If there are any
574	 * filters which require that additional packets in the flow are
575	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
576	 * Note that filters must _never_ set this flag, as another filter
577	 * in the list may have previously cleared it.
578	 */
579	/*
580	 * let ipfilter look at packet on the wire,
581	 * not the decapsulated packet.
582	 */
583#ifdef IPSEC
584	if (!ipsec_getnhist(m))
585#else
586	if (1)
587#endif
588	{
589		struct in_addr odst;
590
591		odst = ip->ip_dst;
592		if (pfil_run_hooks(&inet_pfil_hook, &m, m->m_pkthdr.rcvif,
593		    PFIL_IN) != 0)
594			return;
595		if (m == NULL)
596			return;
597		ip = mtod(m, struct ip *);
598		hlen = ip->ip_hl << 2;
599		srcrt = (odst.s_addr != ip->ip_dst.s_addr);
600	}
601#endif /* PFIL_HOOKS */
602
603#ifdef ALTQ
604	/* XXX Temporary until ALTQ is changed to use a pfil hook */
605	if (altq_input != NULL && (*altq_input)(m, AF_INET) == 0) {
606		/* packet dropped by traffic conditioner */
607		return;
608	}
609#endif
610
611	/*
612	 * Process options and, if not destined for us,
613	 * ship it on.  ip_dooptions returns 1 when an
614	 * error was detected (causing an icmp message
615	 * to be sent and the original packet to be freed).
616	 */
617	ip_nhops = 0;		/* for source routed packets */
618	if (hlen > sizeof (struct ip) && ip_dooptions(m))
619		return;
620
621	/*
622	 * Enable a consistency check between the destination address
623	 * and the arrival interface for a unicast packet (the RFC 1122
624	 * strong ES model) if IP forwarding is disabled and the packet
625	 * is not locally generated.
626	 *
627	 * XXX - Checking also should be disabled if the destination
628	 * address is ipnat'ed to a different interface.
629	 *
630	 * XXX - Checking is incompatible with IP aliases added
631	 * to the loopback interface instead of the interface where
632	 * the packets are received.
633	 *
634	 * XXX - We need to add a per ifaddr flag for this so that
635	 * we get finer grain control.
636	 */
637	checkif = ip_checkinterface && (ipforwarding == 0) &&
638	    (m->m_pkthdr.rcvif != NULL) &&
639	    ((m->m_pkthdr.rcvif->if_flags & IFF_LOOPBACK) == 0);
640
641	/*
642	 * Check our list of addresses, to see if the packet is for us.
643	 *
644	 * Traditional 4.4BSD did not consult IFF_UP at all.
645	 * The behavior here is to treat addresses on !IFF_UP interface
646	 * as not mine.
647	 */
648	downmatch = 0;
649	LIST_FOREACH(ia, &IN_IFADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
650		if (in_hosteq(ia->ia_addr.sin_addr, ip->ip_dst)) {
651			if (checkif && ia->ia_ifp != m->m_pkthdr.rcvif)
652				continue;
653			if ((ia->ia_ifp->if_flags & IFF_UP) != 0)
654				break;
655			else
656				downmatch++;
657		}
658	}
659	if (ia != NULL)
660		goto ours;
661	if (m->m_pkthdr.rcvif->if_flags & IFF_BROADCAST) {
662		TAILQ_FOREACH(ifa, &m->m_pkthdr.rcvif->if_addrlist, ifa_list) {
663			if (ifa->ifa_addr->sa_family != AF_INET)
664				continue;
665			ia = ifatoia(ifa);
666			if (in_hosteq(ip->ip_dst, ia->ia_broadaddr.sin_addr) ||
667			    in_hosteq(ip->ip_dst, ia->ia_netbroadcast) ||
668			    /*
669			     * Look for all-0's host part (old broadcast addr),
670			     * either for subnet or net.
671			     */
672			    ip->ip_dst.s_addr == ia->ia_subnet ||
673			    ip->ip_dst.s_addr == ia->ia_net)
674				goto ours;
675			/*
676			 * An interface with IP address zero accepts
677			 * all packets that arrive on that interface.
678			 */
679			if (in_nullhost(ia->ia_addr.sin_addr))
680				goto ours;
681		}
682	}
683	if (IN_MULTICAST(ip->ip_dst.s_addr)) {
684		struct in_multi *inm;
685#ifdef MROUTING
686		extern struct socket *ip_mrouter;
687
688		if (M_READONLY(m)) {
689			if ((m = m_pullup(m, hlen)) == 0) {
690				ipstat.ips_toosmall++;
691				return;
692			}
693			ip = mtod(m, struct ip *);
694		}
695
696		if (ip_mrouter) {
697			/*
698			 * If we are acting as a multicast router, all
699			 * incoming multicast packets are passed to the
700			 * kernel-level multicast forwarding function.
701			 * The packet is returned (relatively) intact; if
702			 * ip_mforward() returns a non-zero value, the packet
703			 * must be discarded, else it may be accepted below.
704			 *
705			 * (The IP ident field is put in the same byte order
706			 * as expected when ip_mforward() is called from
707			 * ip_output().)
708			 */
709			if (ip_mforward(m, m->m_pkthdr.rcvif) != 0) {
710				ipstat.ips_cantforward++;
711				m_freem(m);
712				return;
713			}
714
715			/*
716			 * The process-level routing demon needs to receive
717			 * all multicast IGMP packets, whether or not this
718			 * host belongs to their destination groups.
719			 */
720			if (ip->ip_p == IPPROTO_IGMP)
721				goto ours;
722			ipstat.ips_forward++;
723		}
724#endif
725		/*
726		 * See if we belong to the destination multicast group on the
727		 * arrival interface.
728		 */
729		IN_LOOKUP_MULTI(ip->ip_dst, m->m_pkthdr.rcvif, inm);
730		if (inm == NULL) {
731			ipstat.ips_cantforward++;
732			m_freem(m);
733			return;
734		}
735		goto ours;
736	}
737	if (ip->ip_dst.s_addr == INADDR_BROADCAST ||
738	    in_nullhost(ip->ip_dst))
739		goto ours;
740
741	/*
742	 * Not for us; forward if possible and desirable.
743	 */
744	if (ipforwarding == 0) {
745		ipstat.ips_cantforward++;
746		m_freem(m);
747	} else {
748		/*
749		 * If ip_dst matched any of my address on !IFF_UP interface,
750		 * and there's no IFF_UP interface that matches ip_dst,
751		 * send icmp unreach.  Forwarding it will result in in-kernel
752		 * forwarding loop till TTL goes to 0.
753		 */
754		if (downmatch) {
755			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
756			ipstat.ips_cantforward++;
757			return;
758		}
759#ifdef IPSEC
760		if (ipsec4_in_reject(m, NULL)) {
761			ipsecstat.in_polvio++;
762			goto bad;
763		}
764#endif
765
766		ip_forward(m, srcrt);
767	}
768	return;
769
770ours:
771	/*
772	 * If offset or IP_MF are set, must reassemble.
773	 * Otherwise, nothing need be done.
774	 * (We could look in the reassembly queue to see
775	 * if the packet was previously fragmented,
776	 * but it's not worth the time; just let them time out.)
777	 */
778	if (ip->ip_off & ~htons(IP_DF|IP_RF)) {
779		if (M_READONLY(m)) {
780			if ((m = m_pullup(m, hlen)) == NULL) {
781				ipstat.ips_toosmall++;
782				goto bad;
783			}
784			ip = mtod(m, struct ip *);
785		}
786
787		/*
788		 * Look for queue of fragments
789		 * of this datagram.
790		 */
791		IPQ_LOCK();
792		LIST_FOREACH(fp, &ipq, ipq_q)
793			if (ip->ip_id == fp->ipq_id &&
794			    in_hosteq(ip->ip_src, fp->ipq_src) &&
795			    in_hosteq(ip->ip_dst, fp->ipq_dst) &&
796			    ip->ip_p == fp->ipq_p)
797				goto found;
798		fp = 0;
799found:
800
801		/*
802		 * Adjust ip_len to not reflect header,
803		 * set ipqe_mff if more fragments are expected,
804		 * convert offset of this to bytes.
805		 */
806		ip->ip_len = htons(ntohs(ip->ip_len) - hlen);
807		mff = (ip->ip_off & htons(IP_MF)) != 0;
808		if (mff) {
809		        /*
810		         * Make sure that fragments have a data length
811			 * that's a non-zero multiple of 8 bytes.
812		         */
813			if (ntohs(ip->ip_len) == 0 ||
814			    (ntohs(ip->ip_len) & 0x7) != 0) {
815				ipstat.ips_badfrags++;
816				IPQ_UNLOCK();
817				goto bad;
818			}
819		}
820		ip->ip_off = htons((ntohs(ip->ip_off) & IP_OFFMASK) << 3);
821
822		/*
823		 * If datagram marked as having more fragments
824		 * or if this is not the first fragment,
825		 * attempt reassembly; if it succeeds, proceed.
826		 */
827		if (mff || ip->ip_off != htons(0)) {
828			ipstat.ips_fragments++;
829			ipqe = pool_get(&ipqent_pool, PR_NOWAIT);
830			if (ipqe == NULL) {
831				ipstat.ips_rcvmemdrop++;
832				IPQ_UNLOCK();
833				goto bad;
834			}
835			ipqe->ipqe_mff = mff;
836			ipqe->ipqe_m = m;
837			ipqe->ipqe_ip = ip;
838			m = ip_reass(ipqe, fp);
839			if (m == 0) {
840				IPQ_UNLOCK();
841				return;
842			}
843			ipstat.ips_reassembled++;
844			ip = mtod(m, struct ip *);
845			hlen = ip->ip_hl << 2;
846			ip->ip_len = htons(ntohs(ip->ip_len) + hlen);
847		} else
848			if (fp)
849				ip_freef(fp);
850		IPQ_UNLOCK();
851	}
852
853#ifdef IPSEC
854	/*
855	 * enforce IPsec policy checking if we are seeing last header.
856	 * note that we do not visit this with protocols with pcb layer
857	 * code - like udp/tcp/raw ip.
858	 */
859	if ((inetsw[ip_protox[ip->ip_p]].pr_flags & PR_LASTHDR) != 0 &&
860	    ipsec4_in_reject(m, NULL)) {
861		ipsecstat.in_polvio++;
862		goto bad;
863	}
864#endif
865
866	/*
867	 * Switch out to protocol's input routine.
868	 */
869#if IFA_STATS
870	if (ia && ip)
871		ia->ia_ifa.ifa_data.ifad_inbytes += ntohs(ip->ip_len);
872#endif
873	ipstat.ips_delivered++;
874    {
875	int off = hlen, nh = ip->ip_p;
876
877	(*inetsw[ip_protox[nh]].pr_input)(m, off, nh);
878	return;
879    }
880bad:
881	m_freem(m);
882	return;
883
884badcsum:
885	ipstat.ips_badsum++;
886	m_freem(m);
887}
888
889/*
890 * Take incoming datagram fragment and try to
891 * reassemble it into whole datagram.  If a chain for
892 * reassembly of this datagram already exists, then it
893 * is given as fp; otherwise have to make a chain.
894 */
895struct mbuf *
896ip_reass(ipqe, fp)
897	struct ipqent *ipqe;
898	struct ipq *fp;
899{
900	struct mbuf *m = ipqe->ipqe_m;
901	struct ipqent *nq, *p, *q;
902	struct ip *ip;
903	struct mbuf *t;
904	int hlen = ipqe->ipqe_ip->ip_hl << 2;
905	int i, next;
906
907	IPQ_LOCK_CHECK();
908
909	/*
910	 * Presence of header sizes in mbufs
911	 * would confuse code below.
912	 */
913	m->m_data += hlen;
914	m->m_len -= hlen;
915
916	/*
917	 * If first fragment to arrive, create a reassembly queue.
918	 */
919	if (fp == 0) {
920		/*
921		 * Enforce upper bound on number of fragmented packets
922		 * for which we attempt reassembly;
923		 * If maxfrag is 0, never accept fragments.
924		 * If maxfrag is -1, accept all fragments without limitation.
925		 */
926		if (ip_maxfragpackets < 0)
927			;
928		else if (ip_nfragpackets >= ip_maxfragpackets)
929			goto dropfrag;
930		ip_nfragpackets++;
931		MALLOC(fp, struct ipq *, sizeof (struct ipq),
932		    M_FTABLE, M_NOWAIT);
933		if (fp == NULL)
934			goto dropfrag;
935		LIST_INSERT_HEAD(&ipq, fp, ipq_q);
936		fp->ipq_ttl = IPFRAGTTL;
937		fp->ipq_p = ipqe->ipqe_ip->ip_p;
938		fp->ipq_id = ipqe->ipqe_ip->ip_id;
939		TAILQ_INIT(&fp->ipq_fragq);
940		fp->ipq_src = ipqe->ipqe_ip->ip_src;
941		fp->ipq_dst = ipqe->ipqe_ip->ip_dst;
942		p = NULL;
943		goto insert;
944	}
945
946	/*
947	 * Find a segment which begins after this one does.
948	 */
949	for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL;
950	    p = q, q = TAILQ_NEXT(q, ipqe_q))
951		if (ntohs(q->ipqe_ip->ip_off) > ntohs(ipqe->ipqe_ip->ip_off))
952			break;
953
954	/*
955	 * If there is a preceding segment, it may provide some of
956	 * our data already.  If so, drop the data from the incoming
957	 * segment.  If it provides all of our data, drop us.
958	 */
959	if (p != NULL) {
960		i = ntohs(p->ipqe_ip->ip_off) + ntohs(p->ipqe_ip->ip_len) -
961		    ntohs(ipqe->ipqe_ip->ip_off);
962		if (i > 0) {
963			if (i >= ntohs(ipqe->ipqe_ip->ip_len))
964				goto dropfrag;
965			m_adj(ipqe->ipqe_m, i);
966			ipqe->ipqe_ip->ip_off =
967			    htons(ntohs(ipqe->ipqe_ip->ip_off) + i);
968			ipqe->ipqe_ip->ip_len =
969			    htons(ntohs(ipqe->ipqe_ip->ip_len) - i);
970		}
971	}
972
973	/*
974	 * While we overlap succeeding segments trim them or,
975	 * if they are completely covered, dequeue them.
976	 */
977	for (; q != NULL &&
978	    ntohs(ipqe->ipqe_ip->ip_off) + ntohs(ipqe->ipqe_ip->ip_len) >
979	    ntohs(q->ipqe_ip->ip_off); q = nq) {
980		i = (ntohs(ipqe->ipqe_ip->ip_off) +
981		    ntohs(ipqe->ipqe_ip->ip_len)) - ntohs(q->ipqe_ip->ip_off);
982		if (i < ntohs(q->ipqe_ip->ip_len)) {
983			q->ipqe_ip->ip_len =
984			    htons(ntohs(q->ipqe_ip->ip_len) - i);
985			q->ipqe_ip->ip_off =
986			    htons(ntohs(q->ipqe_ip->ip_off) + i);
987			m_adj(q->ipqe_m, i);
988			break;
989		}
990		nq = TAILQ_NEXT(q, ipqe_q);
991		m_freem(q->ipqe_m);
992		TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q);
993		pool_put(&ipqent_pool, q);
994	}
995
996insert:
997	/*
998	 * Stick new segment in its place;
999	 * check for complete reassembly.
1000	 */
1001	if (p == NULL) {
1002		TAILQ_INSERT_HEAD(&fp->ipq_fragq, ipqe, ipqe_q);
1003	} else {
1004		TAILQ_INSERT_AFTER(&fp->ipq_fragq, p, ipqe, ipqe_q);
1005	}
1006	next = 0;
1007	for (p = NULL, q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL;
1008	    p = q, q = TAILQ_NEXT(q, ipqe_q)) {
1009		if (ntohs(q->ipqe_ip->ip_off) != next)
1010			return (0);
1011		next += ntohs(q->ipqe_ip->ip_len);
1012	}
1013	if (p->ipqe_mff)
1014		return (0);
1015
1016	/*
1017	 * Reassembly is complete.  Check for a bogus message size and
1018	 * concatenate fragments.
1019	 */
1020	q = TAILQ_FIRST(&fp->ipq_fragq);
1021	ip = q->ipqe_ip;
1022	if ((next + (ip->ip_hl << 2)) > IP_MAXPACKET) {
1023		ipstat.ips_toolong++;
1024		ip_freef(fp);
1025		return (0);
1026	}
1027	m = q->ipqe_m;
1028	t = m->m_next;
1029	m->m_next = 0;
1030	m_cat(m, t);
1031	nq = TAILQ_NEXT(q, ipqe_q);
1032	pool_put(&ipqent_pool, q);
1033	for (q = nq; q != NULL; q = nq) {
1034		t = q->ipqe_m;
1035		nq = TAILQ_NEXT(q, ipqe_q);
1036		pool_put(&ipqent_pool, q);
1037		m_cat(m, t);
1038	}
1039
1040	/*
1041	 * Create header for new ip packet by
1042	 * modifying header of first packet;
1043	 * dequeue and discard fragment reassembly header.
1044	 * Make header visible.
1045	 */
1046	ip->ip_len = htons(next);
1047	ip->ip_src = fp->ipq_src;
1048	ip->ip_dst = fp->ipq_dst;
1049	LIST_REMOVE(fp, ipq_q);
1050	FREE(fp, M_FTABLE);
1051	ip_nfragpackets--;
1052	m->m_len += (ip->ip_hl << 2);
1053	m->m_data -= (ip->ip_hl << 2);
1054	/* some debugging cruft by sklower, below, will go away soon */
1055	if (m->m_flags & M_PKTHDR) { /* XXX this should be done elsewhere */
1056		int plen = 0;
1057		for (t = m; t; t = t->m_next)
1058			plen += t->m_len;
1059		m->m_pkthdr.len = plen;
1060	}
1061	return (m);
1062
1063dropfrag:
1064	ipstat.ips_fragdropped++;
1065	m_freem(m);
1066	pool_put(&ipqent_pool, ipqe);
1067	return (0);
1068}
1069
1070/*
1071 * Free a fragment reassembly header and all
1072 * associated datagrams.
1073 */
1074void
1075ip_freef(fp)
1076	struct ipq *fp;
1077{
1078	struct ipqent *q, *p;
1079
1080	IPQ_LOCK_CHECK();
1081
1082	for (q = TAILQ_FIRST(&fp->ipq_fragq); q != NULL; q = p) {
1083		p = TAILQ_NEXT(q, ipqe_q);
1084		m_freem(q->ipqe_m);
1085		TAILQ_REMOVE(&fp->ipq_fragq, q, ipqe_q);
1086		pool_put(&ipqent_pool, q);
1087	}
1088	LIST_REMOVE(fp, ipq_q);
1089	FREE(fp, M_FTABLE);
1090	ip_nfragpackets--;
1091}
1092
1093/*
1094 * IP timer processing;
1095 * if a timer expires on a reassembly
1096 * queue, discard it.
1097 */
1098void
1099ip_slowtimo()
1100{
1101	struct ipq *fp, *nfp;
1102	int s = splsoftnet();
1103
1104	IPQ_LOCK();
1105	for (fp = LIST_FIRST(&ipq); fp != NULL; fp = nfp) {
1106		nfp = LIST_NEXT(fp, ipq_q);
1107		if (--fp->ipq_ttl == 0) {
1108			ipstat.ips_fragtimeout++;
1109			ip_freef(fp);
1110		}
1111	}
1112	/*
1113	 * If we are over the maximum number of fragments
1114	 * (due to the limit being lowered), drain off
1115	 * enough to get down to the new limit.
1116	 */
1117	if (ip_maxfragpackets < 0)
1118		;
1119	else {
1120		while (ip_nfragpackets > ip_maxfragpackets && LIST_FIRST(&ipq))
1121			ip_freef(LIST_FIRST(&ipq));
1122	}
1123	IPQ_UNLOCK();
1124#ifdef GATEWAY
1125	ipflow_slowtimo();
1126#endif
1127	splx(s);
1128}
1129
1130/*
1131 * Drain off all datagram fragments.
1132 */
1133void
1134ip_drain()
1135{
1136
1137	/*
1138	 * We may be called from a device's interrupt context.  If
1139	 * the ipq is already busy, just bail out now.
1140	 */
1141	if (ipq_lock_try() == 0)
1142		return;
1143
1144	while (LIST_FIRST(&ipq) != NULL) {
1145		ipstat.ips_fragdropped++;
1146		ip_freef(LIST_FIRST(&ipq));
1147	}
1148
1149	IPQ_UNLOCK();
1150}
1151
1152/*
1153 * Do option processing on a datagram,
1154 * possibly discarding it if bad options are encountered,
1155 * or forwarding it if source-routed.
1156 * Returns 1 if packet has been forwarded/freed,
1157 * 0 if the packet should be processed further.
1158 */
1159int
1160ip_dooptions(m)
1161	struct mbuf *m;
1162{
1163	struct ip *ip = mtod(m, struct ip *);
1164	u_char *cp, *cp0;
1165	struct ip_timestamp *ipt;
1166	struct in_ifaddr *ia;
1167	int opt, optlen, cnt, off, code, type = ICMP_PARAMPROB, forward = 0;
1168	struct in_addr dst;
1169	n_time ntime;
1170
1171	dst = ip->ip_dst;
1172	cp = (u_char *)(ip + 1);
1173	cnt = (ip->ip_hl << 2) - sizeof (struct ip);
1174	for (; cnt > 0; cnt -= optlen, cp += optlen) {
1175		opt = cp[IPOPT_OPTVAL];
1176		if (opt == IPOPT_EOL)
1177			break;
1178		if (opt == IPOPT_NOP)
1179			optlen = 1;
1180		else {
1181			if (cnt < IPOPT_OLEN + sizeof(*cp)) {
1182				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1183				goto bad;
1184			}
1185			optlen = cp[IPOPT_OLEN];
1186			if (optlen < IPOPT_OLEN + sizeof(*cp) || optlen > cnt) {
1187				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1188				goto bad;
1189			}
1190		}
1191		switch (opt) {
1192
1193		default:
1194			break;
1195
1196		/*
1197		 * Source routing with record.
1198		 * Find interface with current destination address.
1199		 * If none on this machine then drop if strictly routed,
1200		 * or do nothing if loosely routed.
1201		 * Record interface address and bring up next address
1202		 * component.  If strictly routed make sure next
1203		 * address is on directly accessible net.
1204		 */
1205		case IPOPT_LSRR:
1206		case IPOPT_SSRR:
1207			if (ip_allowsrcrt == 0) {
1208				type = ICMP_UNREACH;
1209				code = ICMP_UNREACH_NET_PROHIB;
1210				goto bad;
1211			}
1212			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1213				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1214				goto bad;
1215			}
1216			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1217				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1218				goto bad;
1219			}
1220			ipaddr.sin_addr = ip->ip_dst;
1221			ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1222			if (ia == 0) {
1223				if (opt == IPOPT_SSRR) {
1224					type = ICMP_UNREACH;
1225					code = ICMP_UNREACH_SRCFAIL;
1226					goto bad;
1227				}
1228				/*
1229				 * Loose routing, and not at next destination
1230				 * yet; nothing to do except forward.
1231				 */
1232				break;
1233			}
1234			off--;			/* 0 origin */
1235			if ((off + sizeof(struct in_addr)) > optlen) {
1236				/*
1237				 * End of source route.  Should be for us.
1238				 */
1239				save_rte(cp, ip->ip_src);
1240				break;
1241			}
1242			/*
1243			 * locate outgoing interface
1244			 */
1245			bcopy((caddr_t)(cp + off), (caddr_t)&ipaddr.sin_addr,
1246			    sizeof(ipaddr.sin_addr));
1247			if (opt == IPOPT_SSRR)
1248				ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)));
1249			else
1250				ia = ip_rtaddr(ipaddr.sin_addr);
1251			if (ia == 0) {
1252				type = ICMP_UNREACH;
1253				code = ICMP_UNREACH_SRCFAIL;
1254				goto bad;
1255			}
1256			ip->ip_dst = ipaddr.sin_addr;
1257			bcopy((caddr_t)&ia->ia_addr.sin_addr,
1258			    (caddr_t)(cp + off), sizeof(struct in_addr));
1259			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1260			/*
1261			 * Let ip_intr's mcast routing check handle mcast pkts
1262			 */
1263			forward = !IN_MULTICAST(ip->ip_dst.s_addr);
1264			break;
1265
1266		case IPOPT_RR:
1267			if (optlen < IPOPT_OFFSET + sizeof(*cp)) {
1268				code = &cp[IPOPT_OLEN] - (u_char *)ip;
1269				goto bad;
1270			}
1271			if ((off = cp[IPOPT_OFFSET]) < IPOPT_MINOFF) {
1272				code = &cp[IPOPT_OFFSET] - (u_char *)ip;
1273				goto bad;
1274			}
1275			/*
1276			 * If no space remains, ignore.
1277			 */
1278			off--;			/* 0 origin */
1279			if ((off + sizeof(struct in_addr)) > optlen)
1280				break;
1281			bcopy((caddr_t)(&ip->ip_dst), (caddr_t)&ipaddr.sin_addr,
1282			    sizeof(ipaddr.sin_addr));
1283			/*
1284			 * locate outgoing interface; if we're the destination,
1285			 * use the incoming interface (should be same).
1286			 */
1287			if ((ia = ifatoia(ifa_ifwithaddr(sintosa(&ipaddr))))
1288			    == NULL &&
1289			    (ia = ip_rtaddr(ipaddr.sin_addr)) == NULL) {
1290				type = ICMP_UNREACH;
1291				code = ICMP_UNREACH_HOST;
1292				goto bad;
1293			}
1294			bcopy((caddr_t)&ia->ia_addr.sin_addr,
1295			    (caddr_t)(cp + off), sizeof(struct in_addr));
1296			cp[IPOPT_OFFSET] += sizeof(struct in_addr);
1297			break;
1298
1299		case IPOPT_TS:
1300			code = cp - (u_char *)ip;
1301			ipt = (struct ip_timestamp *)cp;
1302			if (ipt->ipt_len < 4 || ipt->ipt_len > 40) {
1303				code = (u_char *)&ipt->ipt_len - (u_char *)ip;
1304				goto bad;
1305			}
1306			if (ipt->ipt_ptr < 5) {
1307				code = (u_char *)&ipt->ipt_ptr - (u_char *)ip;
1308				goto bad;
1309			}
1310			if (ipt->ipt_ptr > ipt->ipt_len - sizeof (int32_t)) {
1311				if (++ipt->ipt_oflw == 0) {
1312					code = (u_char *)&ipt->ipt_ptr -
1313					    (u_char *)ip;
1314					goto bad;
1315				}
1316				break;
1317			}
1318			cp0 = (cp + ipt->ipt_ptr - 1);
1319			switch (ipt->ipt_flg) {
1320
1321			case IPOPT_TS_TSONLY:
1322				break;
1323
1324			case IPOPT_TS_TSANDADDR:
1325				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1326				    sizeof(struct in_addr) > ipt->ipt_len) {
1327					code = (u_char *)&ipt->ipt_ptr -
1328					    (u_char *)ip;
1329					goto bad;
1330				}
1331				ipaddr.sin_addr = dst;
1332				ia = ifatoia(ifaof_ifpforaddr(sintosa(&ipaddr),
1333				    m->m_pkthdr.rcvif));
1334				if (ia == 0)
1335					continue;
1336				bcopy(&ia->ia_addr.sin_addr,
1337				    cp0, sizeof(struct in_addr));
1338				ipt->ipt_ptr += sizeof(struct in_addr);
1339				break;
1340
1341			case IPOPT_TS_PRESPEC:
1342				if (ipt->ipt_ptr - 1 + sizeof(n_time) +
1343				    sizeof(struct in_addr) > ipt->ipt_len) {
1344					code = (u_char *)&ipt->ipt_ptr -
1345					    (u_char *)ip;
1346					goto bad;
1347				}
1348				bcopy(cp0, &ipaddr.sin_addr,
1349				    sizeof(struct in_addr));
1350				if (ifatoia(ifa_ifwithaddr(sintosa(&ipaddr)))
1351				    == NULL)
1352					continue;
1353				ipt->ipt_ptr += sizeof(struct in_addr);
1354				break;
1355
1356			default:
1357				/* XXX can't take &ipt->ipt_flg */
1358				code = (u_char *)&ipt->ipt_ptr -
1359				    (u_char *)ip + 1;
1360				goto bad;
1361			}
1362			ntime = iptime();
1363			cp0 = (u_char *) &ntime; /* XXX grumble, GCC... */
1364			bcopy(cp0, (caddr_t)cp + ipt->ipt_ptr - 1,
1365			    sizeof(n_time));
1366			ipt->ipt_ptr += sizeof(n_time);
1367		}
1368	}
1369	if (forward) {
1370		if (ip_forwsrcrt == 0) {
1371			type = ICMP_UNREACH;
1372			code = ICMP_UNREACH_SRCFAIL;
1373			goto bad;
1374		}
1375		ip_forward(m, 1);
1376		return (1);
1377	}
1378	return (0);
1379bad:
1380	icmp_error(m, type, code, 0, 0);
1381	ipstat.ips_badoptions++;
1382	return (1);
1383}
1384
1385/*
1386 * Given address of next destination (final or next hop),
1387 * return internet address info of interface to be used to get there.
1388 */
1389struct in_ifaddr *
1390ip_rtaddr(dst)
1391	 struct in_addr dst;
1392{
1393	struct sockaddr_in *sin;
1394
1395	sin = satosin(&ipforward_rt.ro_dst);
1396
1397	if (ipforward_rt.ro_rt == 0 || !in_hosteq(dst, sin->sin_addr)) {
1398		if (ipforward_rt.ro_rt) {
1399			RTFREE(ipforward_rt.ro_rt);
1400			ipforward_rt.ro_rt = 0;
1401		}
1402		sin->sin_family = AF_INET;
1403		sin->sin_len = sizeof(*sin);
1404		sin->sin_addr = dst;
1405
1406		rtalloc(&ipforward_rt);
1407	}
1408	if (ipforward_rt.ro_rt == 0)
1409		return ((struct in_ifaddr *)0);
1410	return (ifatoia(ipforward_rt.ro_rt->rt_ifa));
1411}
1412
1413/*
1414 * Save incoming source route for use in replies,
1415 * to be picked up later by ip_srcroute if the receiver is interested.
1416 */
1417void
1418save_rte(option, dst)
1419	u_char *option;
1420	struct in_addr dst;
1421{
1422	unsigned olen;
1423
1424	olen = option[IPOPT_OLEN];
1425#ifdef DIAGNOSTIC
1426	if (ipprintfs)
1427		printf("save_rte: olen %d\n", olen);
1428#endif /* 0 */
1429	if (olen > sizeof(ip_srcrt) - (1 + sizeof(dst)))
1430		return;
1431	bcopy((caddr_t)option, (caddr_t)ip_srcrt.srcopt, olen);
1432	ip_nhops = (olen - IPOPT_OFFSET - 1) / sizeof(struct in_addr);
1433	ip_srcrt.dst = dst;
1434}
1435
1436/*
1437 * Retrieve incoming source route for use in replies,
1438 * in the same form used by setsockopt.
1439 * The first hop is placed before the options, will be removed later.
1440 */
1441struct mbuf *
1442ip_srcroute()
1443{
1444	struct in_addr *p, *q;
1445	struct mbuf *m;
1446
1447	if (ip_nhops == 0)
1448		return ((struct mbuf *)0);
1449	m = m_get(M_DONTWAIT, MT_SOOPTS);
1450	if (m == 0)
1451		return ((struct mbuf *)0);
1452
1453	MCLAIM(m, &inetdomain.dom_mowner);
1454#define OPTSIZ	(sizeof(ip_srcrt.nop) + sizeof(ip_srcrt.srcopt))
1455
1456	/* length is (nhops+1)*sizeof(addr) + sizeof(nop + srcrt header) */
1457	m->m_len = ip_nhops * sizeof(struct in_addr) + sizeof(struct in_addr) +
1458	    OPTSIZ;
1459#ifdef DIAGNOSTIC
1460	if (ipprintfs)
1461		printf("ip_srcroute: nhops %d mlen %d", ip_nhops, m->m_len);
1462#endif
1463
1464	/*
1465	 * First save first hop for return route
1466	 */
1467	p = &ip_srcrt.route[ip_nhops - 1];
1468	*(mtod(m, struct in_addr *)) = *p--;
1469#ifdef DIAGNOSTIC
1470	if (ipprintfs)
1471		printf(" hops %x", ntohl(mtod(m, struct in_addr *)->s_addr));
1472#endif
1473
1474	/*
1475	 * Copy option fields and padding (nop) to mbuf.
1476	 */
1477	ip_srcrt.nop = IPOPT_NOP;
1478	ip_srcrt.srcopt[IPOPT_OFFSET] = IPOPT_MINOFF;
1479	bcopy((caddr_t)&ip_srcrt.nop,
1480	    mtod(m, caddr_t) + sizeof(struct in_addr), OPTSIZ);
1481	q = (struct in_addr *)(mtod(m, caddr_t) +
1482	    sizeof(struct in_addr) + OPTSIZ);
1483#undef OPTSIZ
1484	/*
1485	 * Record return path as an IP source route,
1486	 * reversing the path (pointers are now aligned).
1487	 */
1488	while (p >= ip_srcrt.route) {
1489#ifdef DIAGNOSTIC
1490		if (ipprintfs)
1491			printf(" %x", ntohl(q->s_addr));
1492#endif
1493		*q++ = *p--;
1494	}
1495	/*
1496	 * Last hop goes to final destination.
1497	 */
1498	*q = ip_srcrt.dst;
1499#ifdef DIAGNOSTIC
1500	if (ipprintfs)
1501		printf(" %x\n", ntohl(q->s_addr));
1502#endif
1503	return (m);
1504}
1505
1506/*
1507 * Strip out IP options, at higher
1508 * level protocol in the kernel.
1509 * Second argument is buffer to which options
1510 * will be moved, and return value is their length.
1511 * XXX should be deleted; last arg currently ignored.
1512 */
1513void
1514ip_stripoptions(m, mopt)
1515	struct mbuf *m;
1516	struct mbuf *mopt;
1517{
1518	int i;
1519	struct ip *ip = mtod(m, struct ip *);
1520	caddr_t opts;
1521	int olen;
1522
1523	olen = (ip->ip_hl << 2) - sizeof (struct ip);
1524	opts = (caddr_t)(ip + 1);
1525	i = m->m_len - (sizeof (struct ip) + olen);
1526	bcopy(opts  + olen, opts, (unsigned)i);
1527	m->m_len -= olen;
1528	if (m->m_flags & M_PKTHDR)
1529		m->m_pkthdr.len -= olen;
1530	ip->ip_len = htons(ntohs(ip->ip_len) - olen);
1531	ip->ip_hl = sizeof (struct ip) >> 2;
1532}
1533
1534const int inetctlerrmap[PRC_NCMDS] = {
1535	0,		0,		0,		0,
1536	0,		EMSGSIZE,	EHOSTDOWN,	EHOSTUNREACH,
1537	EHOSTUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
1538	EMSGSIZE,	EHOSTUNREACH,	0,		0,
1539	0,		0,		0,		0,
1540	ENOPROTOOPT
1541};
1542
1543/*
1544 * Forward a packet.  If some error occurs return the sender
1545 * an icmp packet.  Note we can't always generate a meaningful
1546 * icmp message because icmp doesn't have a large enough repertoire
1547 * of codes and types.
1548 *
1549 * If not forwarding, just drop the packet.  This could be confusing
1550 * if ipforwarding was zero but some routing protocol was advancing
1551 * us as a gateway to somewhere.  However, we must let the routing
1552 * protocol deal with that.
1553 *
1554 * The srcrt parameter indicates whether the packet is being forwarded
1555 * via a source route.
1556 */
1557void
1558ip_forward(m, srcrt)
1559	struct mbuf *m;
1560	int srcrt;
1561{
1562	struct ip *ip = mtod(m, struct ip *);
1563	struct sockaddr_in *sin;
1564	struct rtentry *rt;
1565	int error, type = 0, code = 0;
1566	struct mbuf *mcopy;
1567	n_long dest;
1568	struct ifnet *destifp;
1569#ifdef IPSEC
1570	struct ifnet dummyifp;
1571#endif
1572
1573	/*
1574	 * We are now in the output path.
1575	 */
1576	MCLAIM(m, &ip_tx_mowner);
1577
1578	/*
1579	 * Clear any in-bound checksum flags for this packet.
1580	 */
1581	m->m_pkthdr.csum_flags = 0;
1582
1583	dest = 0;
1584#ifdef DIAGNOSTIC
1585	if (ipprintfs)
1586		printf("forward: src %2.2x dst %2.2x ttl %x\n",
1587		    ntohl(ip->ip_src.s_addr),
1588		    ntohl(ip->ip_dst.s_addr), ip->ip_ttl);
1589#endif
1590	if (m->m_flags & (M_BCAST|M_MCAST) || in_canforward(ip->ip_dst) == 0) {
1591		ipstat.ips_cantforward++;
1592		m_freem(m);
1593		return;
1594	}
1595	if (ip->ip_ttl <= IPTTLDEC) {
1596		icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, dest, 0);
1597		return;
1598	}
1599	ip->ip_ttl -= IPTTLDEC;
1600
1601	sin = satosin(&ipforward_rt.ro_dst);
1602	if ((rt = ipforward_rt.ro_rt) == 0 ||
1603	    !in_hosteq(ip->ip_dst, sin->sin_addr)) {
1604		if (ipforward_rt.ro_rt) {
1605			RTFREE(ipforward_rt.ro_rt);
1606			ipforward_rt.ro_rt = 0;
1607		}
1608		sin->sin_family = AF_INET;
1609		sin->sin_len = sizeof(struct sockaddr_in);
1610		sin->sin_addr = ip->ip_dst;
1611
1612		rtalloc(&ipforward_rt);
1613		if (ipforward_rt.ro_rt == 0) {
1614			icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, dest, 0);
1615			return;
1616		}
1617		rt = ipforward_rt.ro_rt;
1618	}
1619
1620	/*
1621	 * Save at most 68 bytes of the packet in case
1622	 * we need to generate an ICMP message to the src.
1623	 * Pullup to avoid sharing mbuf cluster between m and mcopy.
1624	 */
1625	mcopy = m_copym(m, 0, imin(ntohs(ip->ip_len), 68), M_DONTWAIT);
1626	if (mcopy)
1627		mcopy = m_pullup(mcopy, ip->ip_hl << 2);
1628
1629	/*
1630	 * If forwarding packet using same interface that it came in on,
1631	 * perhaps should send a redirect to sender to shortcut a hop.
1632	 * Only send redirect if source is sending directly to us,
1633	 * and if packet was not source routed (or has any options).
1634	 * Also, don't send redirect if forwarding using a default route
1635	 * or a route modified by a redirect.
1636	 */
1637	if (rt->rt_ifp == m->m_pkthdr.rcvif &&
1638	    (rt->rt_flags & (RTF_DYNAMIC|RTF_MODIFIED)) == 0 &&
1639	    !in_nullhost(satosin(rt_key(rt))->sin_addr) &&
1640	    ipsendredirects && !srcrt) {
1641		if (rt->rt_ifa &&
1642		    (ip->ip_src.s_addr & ifatoia(rt->rt_ifa)->ia_subnetmask) ==
1643		    ifatoia(rt->rt_ifa)->ia_subnet) {
1644			if (rt->rt_flags & RTF_GATEWAY)
1645				dest = satosin(rt->rt_gateway)->sin_addr.s_addr;
1646			else
1647				dest = ip->ip_dst.s_addr;
1648			/*
1649			 * Router requirements says to only send host
1650			 * redirects.
1651			 */
1652			type = ICMP_REDIRECT;
1653			code = ICMP_REDIRECT_HOST;
1654#ifdef DIAGNOSTIC
1655			if (ipprintfs)
1656				printf("redirect (%d) to %x\n", code,
1657				    (u_int32_t)dest);
1658#endif
1659		}
1660	}
1661
1662#ifdef IPSEC
1663	/* Don't lookup socket in forwarding case */
1664	(void)ipsec_setsocket(m, NULL);
1665#endif
1666	error = ip_output(m, (struct mbuf *)0, &ipforward_rt,
1667	    (IP_FORWARDING | (ip_directedbcast ? IP_ALLOWBROADCAST : 0)), 0);
1668	if (error)
1669		ipstat.ips_cantforward++;
1670	else {
1671		ipstat.ips_forward++;
1672		if (type)
1673			ipstat.ips_redirectsent++;
1674		else {
1675			if (mcopy) {
1676#ifdef GATEWAY
1677				if (mcopy->m_flags & M_CANFASTFWD)
1678					ipflow_create(&ipforward_rt, mcopy);
1679#endif
1680				m_freem(mcopy);
1681			}
1682			return;
1683		}
1684	}
1685	if (mcopy == NULL)
1686		return;
1687	destifp = NULL;
1688
1689	switch (error) {
1690
1691	case 0:				/* forwarded, but need redirect */
1692		/* type, code set above */
1693		break;
1694
1695	case ENETUNREACH:		/* shouldn't happen, checked above */
1696	case EHOSTUNREACH:
1697	case ENETDOWN:
1698	case EHOSTDOWN:
1699	default:
1700		type = ICMP_UNREACH;
1701		code = ICMP_UNREACH_HOST;
1702		break;
1703
1704	case EMSGSIZE:
1705		type = ICMP_UNREACH;
1706		code = ICMP_UNREACH_NEEDFRAG;
1707#ifndef IPSEC
1708		if (ipforward_rt.ro_rt)
1709			destifp = ipforward_rt.ro_rt->rt_ifp;
1710#else
1711		/*
1712		 * If the packet is routed over IPsec tunnel, tell the
1713		 * originator the tunnel MTU.
1714		 *	tunnel MTU = if MTU - sizeof(IP) - ESP/AH hdrsiz
1715		 * XXX quickhack!!!
1716		 */
1717		if (ipforward_rt.ro_rt) {
1718			struct secpolicy *sp;
1719			int ipsecerror;
1720			size_t ipsechdr;
1721			struct route *ro;
1722
1723			sp = ipsec4_getpolicybyaddr(mcopy,
1724			    IPSEC_DIR_OUTBOUND, IP_FORWARDING,
1725			    &ipsecerror);
1726
1727			if (sp == NULL)
1728				destifp = ipforward_rt.ro_rt->rt_ifp;
1729			else {
1730				/* count IPsec header size */
1731				ipsechdr = ipsec4_hdrsiz(mcopy,
1732				    IPSEC_DIR_OUTBOUND, NULL);
1733
1734				/*
1735				 * find the correct route for outer IPv4
1736				 * header, compute tunnel MTU.
1737				 *
1738				 * XXX BUG ALERT
1739				 * The "dummyifp" code relies upon the fact
1740				 * that icmp_error() touches only ifp->if_mtu.
1741				 */
1742				/*XXX*/
1743				destifp = NULL;
1744				if (sp->req != NULL
1745				 && sp->req->sav != NULL
1746				 && sp->req->sav->sah != NULL) {
1747					ro = &sp->req->sav->sah->sa_route;
1748					if (ro->ro_rt && ro->ro_rt->rt_ifp) {
1749						dummyifp.if_mtu =
1750						    ro->ro_rt->rt_rmx.rmx_mtu ?
1751						    ro->ro_rt->rt_rmx.rmx_mtu :
1752						    ro->ro_rt->rt_ifp->if_mtu;
1753						dummyifp.if_mtu -= ipsechdr;
1754						destifp = &dummyifp;
1755					}
1756				}
1757
1758				key_freesp(sp);
1759			}
1760		}
1761#endif /*IPSEC*/
1762		ipstat.ips_cantfrag++;
1763		break;
1764
1765	case ENOBUFS:
1766#if 1
1767		/*
1768		 * a router should not generate ICMP_SOURCEQUENCH as
1769		 * required in RFC1812 Requirements for IP Version 4 Routers.
1770		 * source quench could be a big problem under DoS attacks,
1771		 * or if the underlying interface is rate-limited.
1772		 */
1773		if (mcopy)
1774			m_freem(mcopy);
1775		return;
1776#else
1777		type = ICMP_SOURCEQUENCH;
1778		code = 0;
1779		break;
1780#endif
1781	}
1782	icmp_error(mcopy, type, code, dest, destifp);
1783}
1784
1785void
1786ip_savecontrol(inp, mp, ip, m)
1787	struct inpcb *inp;
1788	struct mbuf **mp;
1789	struct ip *ip;
1790	struct mbuf *m;
1791{
1792
1793	if (inp->inp_socket->so_options & SO_TIMESTAMP) {
1794		struct timeval tv;
1795
1796		microtime(&tv);
1797		*mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
1798		    SCM_TIMESTAMP, SOL_SOCKET);
1799		if (*mp)
1800			mp = &(*mp)->m_next;
1801	}
1802	if (inp->inp_flags & INP_RECVDSTADDR) {
1803		*mp = sbcreatecontrol((caddr_t) &ip->ip_dst,
1804		    sizeof(struct in_addr), IP_RECVDSTADDR, IPPROTO_IP);
1805		if (*mp)
1806			mp = &(*mp)->m_next;
1807	}
1808#ifdef notyet
1809	/*
1810	 * XXX
1811	 * Moving these out of udp_input() made them even more broken
1812	 * than they already were.
1813	 *	- fenner@parc.xerox.com
1814	 */
1815	/* options were tossed already */
1816	if (inp->inp_flags & INP_RECVOPTS) {
1817		*mp = sbcreatecontrol((caddr_t) opts_deleted_above,
1818		    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP);
1819		if (*mp)
1820			mp = &(*mp)->m_next;
1821	}
1822	/* ip_srcroute doesn't do what we want here, need to fix */
1823	if (inp->inp_flags & INP_RECVRETOPTS) {
1824		*mp = sbcreatecontrol((caddr_t) ip_srcroute(),
1825		    sizeof(struct in_addr), IP_RECVRETOPTS, IPPROTO_IP);
1826		if (*mp)
1827			mp = &(*mp)->m_next;
1828	}
1829#endif
1830	if (inp->inp_flags & INP_RECVIF) {
1831		struct sockaddr_dl sdl;
1832
1833		sdl.sdl_len = offsetof(struct sockaddr_dl, sdl_data[0]);
1834		sdl.sdl_family = AF_LINK;
1835		sdl.sdl_index = m->m_pkthdr.rcvif ?
1836		    m->m_pkthdr.rcvif->if_index : 0;
1837		sdl.sdl_nlen = sdl.sdl_alen = sdl.sdl_slen = 0;
1838		*mp = sbcreatecontrol((caddr_t) &sdl, sdl.sdl_len,
1839		    IP_RECVIF, IPPROTO_IP);
1840		if (*mp)
1841			mp = &(*mp)->m_next;
1842	}
1843}
1844
1845int
1846ip_sysctl(name, namelen, oldp, oldlenp, newp, newlen)
1847	int *name;
1848	u_int namelen;
1849	void *oldp;
1850	size_t *oldlenp;
1851	void *newp;
1852	size_t newlen;
1853{
1854	extern int subnetsarelocal, hostzeroisbroadcast;
1855
1856	int error, old;
1857
1858	/* All sysctl names at this level are terminal. */
1859	if (namelen != 1)
1860		return (ENOTDIR);
1861
1862	switch (name[0]) {
1863	case IPCTL_FORWARDING:
1864		return (sysctl_int(oldp, oldlenp, newp, newlen, &ipforwarding));
1865	case IPCTL_SENDREDIRECTS:
1866		return (sysctl_int(oldp, oldlenp, newp, newlen,
1867			&ipsendredirects));
1868	case IPCTL_DEFTTL:
1869		return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_defttl));
1870#ifdef notyet
1871	case IPCTL_DEFMTU:
1872		return (sysctl_int(oldp, oldlenp, newp, newlen, &ip_mtu));
1873#endif
1874	case IPCTL_FORWSRCRT:
1875		/* Don't allow this to change in a secure environment.  */
1876		if (securelevel > 0)
1877			return (sysctl_rdint(oldp, oldlenp, newp,
1878			    ip_forwsrcrt));
1879		else
1880			return (sysctl_int(oldp, oldlenp, newp, newlen,
1881			    &ip_forwsrcrt));
1882	case IPCTL_DIRECTEDBCAST:
1883		return (sysctl_int(oldp, oldlenp, newp, newlen,
1884		    &ip_directedbcast));
1885	case IPCTL_ALLOWSRCRT:
1886		return (sysctl_int(oldp, oldlenp, newp, newlen,
1887		    &ip_allowsrcrt));
1888	case IPCTL_SUBNETSARELOCAL:
1889		return (sysctl_int(oldp, oldlenp, newp, newlen,
1890		    &subnetsarelocal));
1891	case IPCTL_MTUDISC:
1892		error = sysctl_int(oldp, oldlenp, newp, newlen,
1893		    &ip_mtudisc);
1894		if (error == 0 && ip_mtudisc == 0)
1895			rt_timer_queue_remove_all(ip_mtudisc_timeout_q, TRUE);
1896		return error;
1897	case IPCTL_ANONPORTMIN:
1898		old = anonportmin;
1899		error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmin);
1900		if (anonportmin >= anonportmax || anonportmin < 0
1901		    || anonportmin > 65535
1902#ifndef IPNOPRIVPORTS
1903		    || anonportmin < IPPORT_RESERVED
1904#endif
1905		    ) {
1906			anonportmin = old;
1907			return (EINVAL);
1908		}
1909		return (error);
1910	case IPCTL_ANONPORTMAX:
1911		old = anonportmax;
1912		error = sysctl_int(oldp, oldlenp, newp, newlen, &anonportmax);
1913		if (anonportmin >= anonportmax || anonportmax < 0
1914		    || anonportmax > 65535
1915#ifndef IPNOPRIVPORTS
1916		    || anonportmax < IPPORT_RESERVED
1917#endif
1918		    ) {
1919			anonportmax = old;
1920			return (EINVAL);
1921		}
1922		return (error);
1923	case IPCTL_MTUDISCTIMEOUT:
1924		old = ip_mtudisc_timeout;
1925		error = sysctl_int(oldp, oldlenp, newp, newlen,
1926		   &ip_mtudisc_timeout);
1927		if (ip_mtudisc_timeout < 0) {
1928			ip_mtudisc_timeout = old;
1929			return (EINVAL);
1930		}
1931		if (error == 0)
1932			rt_timer_queue_change(ip_mtudisc_timeout_q,
1933					      ip_mtudisc_timeout);
1934		return (error);
1935#ifdef GATEWAY
1936	case IPCTL_MAXFLOWS:
1937	    {
1938		int s;
1939
1940		error = sysctl_int(oldp, oldlenp, newp, newlen,
1941		   &ip_maxflows);
1942		s = splsoftnet();
1943		ipflow_reap(0);
1944		splx(s);
1945		return (error);
1946	    }
1947#endif
1948	case IPCTL_HOSTZEROBROADCAST:
1949		return (sysctl_int(oldp, oldlenp, newp, newlen,
1950		    &hostzeroisbroadcast));
1951#if NGIF > 0
1952	case IPCTL_GIF_TTL:
1953		return (sysctl_int(oldp, oldlenp, newp, newlen,
1954				  &ip_gif_ttl));
1955#endif
1956
1957#if NGRE > 0
1958	case IPCTL_GRE_TTL:
1959		return (sysctl_int(oldp, oldlenp, newp, newlen,
1960				  &ip_gre_ttl));
1961#endif
1962
1963#ifndef IPNOPRIVPORTS
1964	case IPCTL_LOWPORTMIN:
1965		old = lowportmin;
1966		error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmin);
1967		if (lowportmin >= lowportmax
1968		    || lowportmin > IPPORT_RESERVEDMAX
1969		    || lowportmin < IPPORT_RESERVEDMIN
1970		    ) {
1971			lowportmin = old;
1972			return (EINVAL);
1973		}
1974		return (error);
1975	case IPCTL_LOWPORTMAX:
1976		old = lowportmax;
1977		error = sysctl_int(oldp, oldlenp, newp, newlen, &lowportmax);
1978		if (lowportmin >= lowportmax
1979		    || lowportmax > IPPORT_RESERVEDMAX
1980		    || lowportmax < IPPORT_RESERVEDMIN
1981		    ) {
1982			lowportmax = old;
1983			return (EINVAL);
1984		}
1985		return (error);
1986#endif
1987
1988	case IPCTL_MAXFRAGPACKETS:
1989		return (sysctl_int(oldp, oldlenp, newp, newlen,
1990		    &ip_maxfragpackets));
1991
1992	case IPCTL_CHECKINTERFACE:
1993		return (sysctl_int(oldp, oldlenp, newp, newlen,
1994		    &ip_checkinterface));
1995	default:
1996		return (EOPNOTSUPP);
1997	}
1998	/* NOTREACHED */
1999}
2000