[BACK]Return to ip6_input.c CVS log [TXT][DIR] Up to [cvs.NetBSD.org] / src / sys / netinet6

File: [cvs.NetBSD.org] / src / sys / netinet6 / ip6_input.c (download)

Revision 1.208.2.2, Tue Sep 24 03:10:35 2019 UTC (2 months, 1 week ago) by martin
Branch: netbsd-9
Changes since 1.208.2.1: +11 -11 lines

Pull up following revision(s) (requested by ozaki-r in ticket #238):

	sys/netipsec/ipsec_output.c: revision 1.83
	sys/net/route.h: revision 1.125
	sys/netinet6/ip6_input.c: revision 1.210
	sys/netinet6/ip6_input.c: revision 1.211
	sys/net/if.c: revision 1.461
	sys/net/if_gif.h: revision 1.33
	sys/net/route.c: revision 1.220
	sys/net/route.c: revision 1.221
	sys/net/if.h: revision 1.277
	sys/netinet6/ip6_forward.c: revision 1.97
	sys/netinet/wqinput.c: revision 1.6
	sys/net/if_ipsec.h: revision 1.5
	sys/netinet6/in6_l2tp.c: revision 1.18
	sys/netinet6/in6_gif.c: revision 1.94
	sys/net/if_l2tp.h: revision 1.7
	sys/net/if_gif.c: revision 1.149
	sys/net/if_l2tp.h: revision 1.8
	sys/netinet/in_gif.c: revision 1.95
	sys/netinet/in_l2tp.c: revision 1.17
	sys/netipsec/ipsecif.c: revision 1.17
	sys/net/if_ipsec.c: revision 1.24
	sys/net/if_l2tp.c: revision 1.37
	sys/netinet/ip_input.c: revision 1.391
	sys/net/if_l2tp.c: revision 1.38
	sys/netinet/ip_input.c: revision 1.392
	sys/net/if_l2tp.c: revision 1.39

Avoid having a rtcache directly in a percpu storage

percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users.  If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.

A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Using rtcache, i.e., packet processing, typically involves sleepable operations
such as rwlock so we must avoid dereferencing a rtcache that is directly stored
in a percpu storage during packet processing.  Address this situation by having
just a pointer to a rtcache in a percpu storage instead.
Reviewed by knakahara@ and yamaguchi@

 -

wqinput: avoid having struct wqinput_worklist directly in a percpu storage

percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users.  If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.

A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Input handlers of wqinput normally involves sleepable operations so we must
avoid dereferencing a percpu data (struct wqinput_worklist) after executing
an input handler.  Address this situation by having just a pointer to the data
in a percpu storage instead.
Reviewed by knakahara@ and yamaguchi@

 -

Add missing #include <sys/kmem.h>

 -

Divide Tx context of l2tp(4) to improve performance.

It seems l2tp(4) call path is too long for instruction cache. So, dividing
l2tp(4) Tx context improves CPU use efficiency.

After this commit, l2tp(4) throughput gains 10% on my machine(Atom C3000).

 -

Apply some missing changes lost on the previous commit

 -

Avoid having a rtcache directly in a percpu storage for tunnel protocols.
percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users.  If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.

A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Using rtcache, i.e., packet processing, typically involves sleepable operations
such as rwlock so we must avoid dereferencing a rtcache that is directly stored
in a percpu storage during packet processing.  Address this situation by having
just a pointer to a rtcache in a percpu storage instead.

Reviewed by ozaki-r@ and yamaguchi@

 -

l2tp(4): avoid having struct ifqueue directly in a percpu storage.
percpu(9) has a certain memory storage for each CPU and provides it by the piece
to users.  If the storages went short, percpu(9) enlarges them by allocating new
larger memory areas, replacing old ones with them and destroying the old ones.

A percpu storage referenced by a pointer gotten via percpu_getref can be
destroyed by the mechanism after a running thread sleeps even if percpu_putref
has not been called.

Tx processing of l2tp(4) uses normally involves sleepable operations so we
must avoid dereferencing a percpu data (struct ifqueue) after executing Tx
processing.  Address this situation by having just a pointer to the data in
a percpu storage instead.

Reviewed by ozaki-r@ and yamaguchi@

/*	$NetBSD: ip6_input.c,v 1.208.2.2 2019/09/24 03:10:35 martin Exp $	*/
/*	$KAME: ip6_input.c,v 1.188 2001/03/29 05:34:31 itojun Exp $	*/

/*
 * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the project nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE PROJECT AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE PROJECT OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Copyright (c) 1982, 1986, 1988, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 *	@(#)ip_input.c	8.2 (Berkeley) 1/4/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ip6_input.c,v 1.208.2.2 2019/09/24 03:10:35 martin Exp $");

#ifdef _KERNEL_OPT
#include "opt_gateway.h"
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_ipsec.h"
#include "opt_net_mpsafe.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/syslog.h>
#include <sys/proc.h>
#include <sys/sysctl.h>
#include <sys/cprng.h>
#include <sys/percpu.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/pktqueue.h>
#include <net/pfil.h>

#include <netinet/in.h>
#include <netinet/in_systm.h>
#ifdef INET
#include <netinet/ip.h>
#include <netinet/ip_var.h>
#include <netinet/ip_icmp.h>
#endif /* INET */
#include <netinet/ip6.h>
#include <netinet/portalgo.h>
#include <netinet6/in6_var.h>
#include <netinet6/ip6_var.h>
#include <netinet6/ip6_private.h>
#include <netinet6/in6_pcb.h>
#include <netinet/icmp6.h>
#include <netinet6/scope6_var.h>
#include <netinet6/in6_ifattach.h>
#include <netinet6/nd6.h>

#ifdef IPSEC
#include <netipsec/ipsec.h>
#include <netipsec/ipsec6.h>
#include <netipsec/key.h>
#endif /* IPSEC */

#include <netinet6/ip6protosw.h>

#include "faith.h"

extern struct domain inet6domain;

u_char ip6_protox[IPPROTO_MAX];
pktqueue_t *ip6_pktq __read_mostly;

pfil_head_t *inet6_pfil_hook;

percpu_t *ip6stat_percpu;

percpu_t *ip6_forward_rt_percpu __cacheline_aligned;

static void ip6_init2(void);
static void ip6intr(void *);
static bool ip6_badaddr(struct ip6_hdr *);
static struct m_tag *ip6_setdstifaddr(struct mbuf *, const struct in6_ifaddr *);

static int ip6_process_hopopts(struct mbuf *, u_int8_t *, int, u_int32_t *,
    u_int32_t *);
static struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);
static void sysctl_net_inet6_ip6_setup(struct sysctllog **);

#ifdef NET_MPSAFE
#define	SOFTNET_LOCK()		mutex_enter(softnet_lock)
#define	SOFTNET_UNLOCK()	mutex_exit(softnet_lock)
#else
#define	SOFTNET_LOCK()		KASSERT(mutex_owned(softnet_lock))
#define	SOFTNET_UNLOCK()	KASSERT(mutex_owned(softnet_lock))
#endif

/*
 * IP6 initialization: fill in IP6 protocol switch table.
 * All protocols not implemented in kernel go to raw IP6 protocol handler.
 */
void
ip6_init(void)
{
	const struct ip6protosw *pr;
	int i;

	in6_init();

	sysctl_net_inet6_ip6_setup(NULL);
	pr = (const struct ip6protosw *)pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
	if (pr == 0)
		panic("ip6_init");
	for (i = 0; i < IPPROTO_MAX; i++)
		ip6_protox[i] = pr - inet6sw;
	for (pr = (const struct ip6protosw *)inet6domain.dom_protosw;
	    pr < (const struct ip6protosw *)inet6domain.dom_protoswNPROTOSW; pr++)
		if (pr->pr_domain->dom_family == PF_INET6 &&
		    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW)
			ip6_protox[pr->pr_protocol] = pr - inet6sw;

	ip6_pktq = pktq_create(IFQ_MAXLEN, ip6intr, NULL);
	KASSERT(ip6_pktq != NULL);

	scope6_init();
	addrsel_policy_init();
	nd6_init();
	frag6_init();
	ip6_desync_factor = cprng_fast32() % MAX_TEMP_DESYNC_FACTOR;

	ip6_init2();
#ifdef GATEWAY
	ip6flow_init(ip6_hashsize);
#endif
	/* Register our Packet Filter hook. */
	inet6_pfil_hook = pfil_head_create(PFIL_TYPE_AF, (void *)AF_INET6);
	KASSERT(inet6_pfil_hook != NULL);

	ip6stat_percpu = percpu_alloc(sizeof(uint64_t) * IP6_NSTATS);
	ip6_forward_rt_percpu = rtcache_percpu_alloc();
}

static void
ip6_init2(void)
{

	/* timer for regeneration of temporary addresses randomize ID */
	callout_init(&in6_tmpaddrtimer_ch, CALLOUT_MPSAFE);
	callout_reset(&in6_tmpaddrtimer_ch,
		      (ip6_temp_preferred_lifetime - ip6_desync_factor -
		       ip6_temp_regen_advance) * hz,
		      in6_tmpaddrtimer, NULL);
}

/*
 * IP6 input interrupt handling. Just pass the packet to ip6_input.
 */
static void
ip6intr(void *arg __unused)
{
	struct mbuf *m;

	SOFTNET_KERNEL_LOCK_UNLESS_NET_MPSAFE();
	while ((m = pktq_dequeue(ip6_pktq)) != NULL) {
		struct psref psref;
		struct ifnet *rcvif = m_get_rcvif_psref(m, &psref);

		if (rcvif == NULL) {
			m_freem(m);
			continue;
		}
		/*
		 * Drop the packet if IPv6 is disabled on the interface.
		 */
		if ((ND_IFINFO(rcvif)->flags & ND6_IFF_IFDISABLED)) {
			m_put_rcvif_psref(rcvif, &psref);
			m_freem(m);
			continue;
		}
		ip6_input(m, rcvif);
		m_put_rcvif_psref(rcvif, &psref);
	}
	SOFTNET_KERNEL_UNLOCK_UNLESS_NET_MPSAFE();
}

void
ip6_input(struct mbuf *m, struct ifnet *rcvif)
{
	struct ip6_hdr *ip6;
	int hit, off = sizeof(struct ip6_hdr), nest;
	u_int32_t plen;
	u_int32_t rtalert = ~0;
	int nxt, ours = 0, rh_present = 0, frg_present;
	struct ifnet *deliverifp = NULL;
	int srcrt = 0;
	struct rtentry *rt = NULL;
	union {
		struct sockaddr		dst;
		struct sockaddr_in6	dst6;
	} u;
	struct route *ro;

	KASSERT(rcvif != NULL);

	/*
	 * make sure we don't have onion peering information into m_tag.
	 */
	ip6_delaux(m);

	/*
	 * mbuf statistics
	 */
	if (m->m_flags & M_EXT) {
		if (m->m_next)
			IP6_STATINC(IP6_STAT_MEXT2M);
		else
			IP6_STATINC(IP6_STAT_MEXT1);
	} else {
#define M2MMAX	32
		if (m->m_next) {
			if (m->m_flags & M_LOOP)
			/*XXX*/	IP6_STATINC(IP6_STAT_M2M + lo0ifp->if_index);
			else if (rcvif->if_index < M2MMAX)
				IP6_STATINC(IP6_STAT_M2M + rcvif->if_index);
			else
				IP6_STATINC(IP6_STAT_M2M);
		} else
			IP6_STATINC(IP6_STAT_M1);
#undef M2MMAX
	}

	in6_ifstat_inc(rcvif, ifs6_in_receive);
	IP6_STATINC(IP6_STAT_TOTAL);

	/*
	 * If the IPv6 header is not aligned, slurp it up into a new
	 * mbuf with space for link headers, in the event we forward
	 * it.  Otherwise, if it is aligned, make sure the entire base
	 * IPv6 header is in the first mbuf of the chain.
	 */
	if (IP6_HDR_ALIGNED_P(mtod(m, void *)) == 0) {
		if ((m = m_copyup(m, sizeof(struct ip6_hdr),
		    (max_linkhdr + 3) & ~3)) == NULL) {
			/* XXXJRT new stat, please */
			IP6_STATINC(IP6_STAT_TOOSMALL);
			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
			return;
		}
	} else if (__predict_false(m->m_len < sizeof(struct ip6_hdr))) {
		if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
			IP6_STATINC(IP6_STAT_TOOSMALL);
			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
			return;
		}
	}

	ip6 = mtod(m, struct ip6_hdr *);

	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
		IP6_STATINC(IP6_STAT_BADVERS);
		in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
		goto bad;
	}

	if (ip6_badaddr(ip6)) {
		IP6_STATINC(IP6_STAT_BADSCOPE);
		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
		goto bad;
	}

	/*
	 * Assume that we can create a fast-forward IP flow entry
	 * based on this packet.
	 */
	m->m_flags |= M_CANFASTFWD;

	/*
	 * Run through list of hooks for input packets.  If there are any
	 * filters which require that additional packets in the flow are
	 * not fast-forwarded, they must clear the M_CANFASTFWD flag.
	 * Note that filters must _never_ set this flag, as another filter
	 * in the list may have previously cleared it.
	 *
	 * Don't call hooks if the packet has already been processed by
	 * IPsec (encapsulated, tunnel mode).
	 */
#if defined(IPSEC)
	if (!ipsec_used || !ipsec_skip_pfil(m))
#else
	if (1)
#endif
	{
		struct in6_addr odst;
		int error;

		odst = ip6->ip6_dst;
		error = pfil_run_hooks(inet6_pfil_hook, &m, rcvif, PFIL_IN);
		if (error != 0 || m == NULL) {
			IP6_STATINC(IP6_STAT_PFILDROP_IN);
			return;
		}
		if (m->m_len < sizeof(struct ip6_hdr)) {
			if ((m = m_pullup(m, sizeof(struct ip6_hdr))) == NULL) {
				IP6_STATINC(IP6_STAT_TOOSMALL);
				in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
				return;
			}
		}
		ip6 = mtod(m, struct ip6_hdr *);
		srcrt = !IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst);
	}

	IP6_STATINC(IP6_STAT_NXTHIST + ip6->ip6_nxt);

#ifdef ALTQ
	if (altq_input != NULL) {
		SOFTNET_LOCK();
		if ((*altq_input)(m, AF_INET6) == 0) {
			SOFTNET_UNLOCK();
			/* packet is dropped by traffic conditioner */
			return;
		}
		SOFTNET_UNLOCK();
	}
#endif

	/*
	 * Disambiguate address scope zones (if there is ambiguity).
	 * We first make sure that the original source or destination address
	 * is not in our internal form for scoped addresses.  Such addresses
	 * are not necessarily invalid spec-wise, but we cannot accept them due
	 * to the usage conflict.
	 * in6_setscope() then also checks and rejects the cases where src or
	 * dst are the loopback address and the receiving interface
	 * is not loopback.
	 */
	if (__predict_false(
	    m_makewritable(&m, 0, sizeof(struct ip6_hdr), M_DONTWAIT)))
		goto bad;
	ip6 = mtod(m, struct ip6_hdr *);
	if (in6_clearscope(&ip6->ip6_src) || in6_clearscope(&ip6->ip6_dst)) {
		IP6_STATINC(IP6_STAT_BADSCOPE);	/* XXX */
		goto bad;
	}
	if (in6_setscope(&ip6->ip6_src, rcvif, NULL) ||
	    in6_setscope(&ip6->ip6_dst, rcvif, NULL)) {
		IP6_STATINC(IP6_STAT_BADSCOPE);
		goto bad;
	}

	ro = rtcache_percpu_getref(ip6_forward_rt_percpu);

	/*
	 * Multicast check
	 */
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
		bool ingroup;

		in6_ifstat_inc(rcvif, ifs6_in_mcast);
		/*
		 * See if we belong to the destination multicast group on the
		 * arrival interface.
		 */
		ingroup = in6_multi_group(&ip6->ip6_dst, rcvif);
		if (ingroup) {
			ours = 1;
		} else if (!ip6_mrouter) {
			uint64_t *ip6s = IP6_STAT_GETREF();
			ip6s[IP6_STAT_NOTMEMBER]++;
			ip6s[IP6_STAT_CANTFORWARD]++;
			IP6_STAT_PUTREF();
			in6_ifstat_inc(rcvif, ifs6_in_discard);
			goto bad_unref;
		}
		deliverifp = rcvif;
		goto hbhcheck;
	}

	sockaddr_in6_init(&u.dst6, &ip6->ip6_dst, 0, 0, 0);

	/*
	 * Unicast check
	 */
	rt = rtcache_lookup2(ro, &u.dst, 1, &hit);
	if (hit)
		IP6_STATINC(IP6_STAT_FORWARD_CACHEHIT);
	else
		IP6_STATINC(IP6_STAT_FORWARD_CACHEMISS);

	/*
	 * Accept the packet if the forwarding interface to the destination
	 * (according to the routing table) is the loopback interface,
	 * unless the associated route has a gateway.
	 *
	 * We don't explicitly match ip6_dst against an interface here. It
	 * is already done in rtcache_lookup2: rt->rt_ifp->if_type will be
	 * IFT_LOOP if the packet is for us.
	 *
	 * Note that this approach causes to accept a packet if there is a
	 * route to the loopback interface for the destination of the packet.
	 * But we think it's even useful in some situations, e.g. when using
	 * a special daemon which wants to intercept the packet.
	 */
	if (rt != NULL &&
	    (rt->rt_flags & (RTF_HOST|RTF_GATEWAY)) == RTF_HOST &&
	    rt->rt_ifp->if_type == IFT_LOOP) {
		struct in6_ifaddr *ia6 = (struct in6_ifaddr *)rt->rt_ifa;
		int addrok;

		if (ia6->ia6_flags & IN6_IFF_ANYCAST)
			m->m_flags |= M_ANYCAST6;
		/*
		 * packets to a tentative, duplicated, or somehow invalid
		 * address must not be accepted.
		 */
		if (ia6->ia6_flags & IN6_IFF_NOTREADY)
			addrok = 0;
		else if (ia6->ia6_flags & IN6_IFF_DETACHED &&
		    !IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_src))
		{
			/* Allow internal traffic to DETACHED addresses */
			struct sockaddr_in6 sin6;
			int s;

			memset(&sin6, 0, sizeof(sin6));
			sin6.sin6_family = AF_INET6;
			sin6.sin6_len = sizeof(sin6);
			sin6.sin6_addr = ip6->ip6_src;
			s = pserialize_read_enter();
			addrok = (ifa_ifwithaddr(sin6tosa(&sin6)) != NULL);
			pserialize_read_exit(s);
		} else
			addrok = 1;
		if (addrok) {
			/* this address is ready */
			ours = 1;
			deliverifp = ia6->ia_ifp;	/* correct? */
			goto hbhcheck;
		} else {
			/* address is not ready, so discard the packet. */
			char ip6bufs[INET6_ADDRSTRLEN];
			char ip6bufd[INET6_ADDRSTRLEN];
			nd6log(LOG_INFO, "packet to an unready address %s->%s\n",
			    IN6_PRINT(ip6bufs, &ip6->ip6_src),
			    IN6_PRINT(ip6bufd, &ip6->ip6_dst));

			goto bad_unref;
		}
	}

	/*
	 * FAITH (Firewall Aided Internet Translator)
	 */
#if defined(NFAITH) && 0 < NFAITH
	if (ip6_keepfaith) {
		if (rt != NULL && rt->rt_ifp != NULL &&
		    rt->rt_ifp->if_type == IFT_FAITH) {
			/* XXX do we need more sanity checks? */
			ours = 1;
			deliverifp = rt->rt_ifp; /* faith */
			goto hbhcheck;
		}
	}
#endif

	/*
	 * Now there is no reason to process the packet if it's not our own
	 * and we're not a router.
	 */
	if (!ip6_forwarding) {
		IP6_STATINC(IP6_STAT_CANTFORWARD);
		in6_ifstat_inc(rcvif, ifs6_in_discard);
		goto bad_unref;
	}

hbhcheck:
	/*
	 * Record address information into m_tag, if we don't have one yet.
	 * Note that we are unable to record it, if the address is not listed
	 * as our interface address (e.g. multicast addresses, addresses
	 * within FAITH prefixes and such).
	 */
	if (deliverifp && ip6_getdstifaddr(m) == NULL) {
		struct in6_ifaddr *ia6;
		int s = pserialize_read_enter();

		ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
		/* Depends on ip6_setdstifaddr never sleep */
		if (ia6 != NULL && ip6_setdstifaddr(m, ia6) == NULL) {
			/*
			 * XXX maybe we should drop the packet here,
			 * as we could not provide enough information
			 * to the upper layers.
			 */
		}
		pserialize_read_exit(s);
	}

	/*
	 * Process Hop-by-Hop options header if it's contained.
	 * m may be modified in ip6_hopopts_input().
	 * If a JumboPayload option is included, plen will also be modified.
	 */
	plen = (u_int32_t)ntohs(ip6->ip6_plen);
	if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
		struct ip6_hbh *hbh;

		if (ip6_hopopts_input(&plen, &rtalert, &m, &off)) {
			/* m already freed */
			in6_ifstat_inc(rcvif, ifs6_in_discard);
			rtcache_unref(rt, ro);
			rtcache_percpu_putref(ip6_forward_rt_percpu);
			return;
		}

		/* adjust pointer */
		ip6 = mtod(m, struct ip6_hdr *);

		/*
		 * if the payload length field is 0 and the next header field
		 * indicates Hop-by-Hop Options header, then a Jumbo Payload
		 * option MUST be included.
		 */
		if (ip6->ip6_plen == 0 && plen == 0) {
			/*
			 * Note that if a valid jumbo payload option is
			 * contained, ip6_hopopts_input() must set a valid
			 * (non-zero) payload length to the variable plen.
			 */
			IP6_STATINC(IP6_STAT_BADOPTIONS);
			in6_ifstat_inc(rcvif, ifs6_in_discard);
			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
			icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    (char *)&ip6->ip6_plen - (char *)ip6);
			rtcache_unref(rt, ro);
			rtcache_percpu_putref(ip6_forward_rt_percpu);
			return;
		}
		IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
			sizeof(struct ip6_hbh));
		if (hbh == NULL) {
			IP6_STATINC(IP6_STAT_TOOSHORT);
			rtcache_unref(rt, ro);
			rtcache_percpu_putref(ip6_forward_rt_percpu);
			return;
		}
		KASSERT(IP6_HDR_ALIGNED_P(hbh));
		nxt = hbh->ip6h_nxt;

		/*
		 * accept the packet if a router alert option is included
		 * and we act as an IPv6 router.
		 */
		if (rtalert != ~0 && ip6_forwarding)
			ours = 1;
	} else
		nxt = ip6->ip6_nxt;

	/*
	 * Check that the amount of data in the buffers is at least much as
	 * the IPv6 header would have us expect. Trim mbufs if longer than we
	 * expect. Drop packet if shorter than we expect.
	 */
	if (m->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
		IP6_STATINC(IP6_STAT_TOOSHORT);
		in6_ifstat_inc(rcvif, ifs6_in_truncated);
		goto bad_unref;
	}
	if (m->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
		if (m->m_len == m->m_pkthdr.len) {
			m->m_len = sizeof(struct ip6_hdr) + plen;
			m->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
		} else
			m_adj(m, sizeof(struct ip6_hdr) + plen - m->m_pkthdr.len);
	}

	/*
	 * Forward if desirable.
	 */
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
		/*
		 * If we are acting as a multicast router, all
		 * incoming multicast packets are passed to the
		 * kernel-level multicast forwarding function.
		 * The packet is returned (relatively) intact; if
		 * ip6_mforward() returns a non-zero value, the packet
		 * must be discarded, else it may be accepted below.
		 */
		if (ip6_mrouter != NULL) {
			int error;

			SOFTNET_LOCK();
			error = ip6_mforward(ip6, rcvif, m);
			SOFTNET_UNLOCK();

			if (error != 0) {
				rtcache_unref(rt, ro);
				rtcache_percpu_putref(ip6_forward_rt_percpu);
				IP6_STATINC(IP6_STAT_CANTFORWARD);
				goto bad;
			}
		}
		if (!ours)
			goto bad_unref;
	} else if (!ours) {
		rtcache_unref(rt, ro);
		rtcache_percpu_putref(ip6_forward_rt_percpu);
		ip6_forward(m, srcrt);
		return;
	}

	ip6 = mtod(m, struct ip6_hdr *);

	/*
	 * Malicious party may be able to use IPv4 mapped addr to confuse
	 * tcp/udp stack and bypass security checks (act as if it was from
	 * 127.0.0.1 by using IPv6 src ::ffff:127.0.0.1).  Be cautious.
	 *
	 * For SIIT end node behavior, you may want to disable the check.
	 * However, you will  become vulnerable to attacks using IPv4 mapped
	 * source.
	 */
	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
		IP6_STATINC(IP6_STAT_BADSCOPE);
		in6_ifstat_inc(rcvif, ifs6_in_addrerr);
		goto bad_unref;
	}

#ifdef IFA_STATS
	if (deliverifp != NULL) {
		struct in6_ifaddr *ia6;
		int s = pserialize_read_enter();
		ia6 = in6_ifawithifp(deliverifp, &ip6->ip6_dst);
		if (ia6)
			ia6->ia_ifa.ifa_data.ifad_inbytes += m->m_pkthdr.len;
		pserialize_read_exit(s);
	}
#endif
	IP6_STATINC(IP6_STAT_DELIVERED);
	in6_ifstat_inc(deliverifp, ifs6_in_deliver);
	nest = 0;

	if (rt != NULL) {
		rtcache_unref(rt, ro);
		rt = NULL;
	}
	rtcache_percpu_putref(ip6_forward_rt_percpu);

	rh_present = 0;
	frg_present = 0;
	while (nxt != IPPROTO_DONE) {
		if (ip6_hdrnestlimit && (++nest > ip6_hdrnestlimit)) {
			IP6_STATINC(IP6_STAT_TOOMANYHDR);
			in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
			goto bad;
		}

		M_VERIFY_PACKET(m);

		/*
		 * protection against faulty packet - there should be
		 * more sanity checks in header chain processing.
		 */
		if (m->m_pkthdr.len < off) {
			IP6_STATINC(IP6_STAT_TOOSHORT);
			in6_ifstat_inc(rcvif, ifs6_in_truncated);
			goto bad;
		}

		if (nxt == IPPROTO_ROUTING) {
			if (rh_present++) {
				in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
				IP6_STATINC(IP6_STAT_BADOPTIONS);
				goto bad;
			}
		} else if (nxt == IPPROTO_FRAGMENT) {
			if (frg_present++) {
				in6_ifstat_inc(rcvif, ifs6_in_hdrerr);
				IP6_STATINC(IP6_STAT_BADOPTIONS);
				goto bad;
			}
		}

#ifdef IPSEC
		if (ipsec_used) {
			/*
			 * Enforce IPsec policy checking if we are seeing last
			 * header. Note that we do not visit this with
			 * protocols with pcb layer code - like udp/tcp/raw ip.
			 */
			if ((inet6sw[ip6_protox[nxt]].pr_flags
			    & PR_LASTHDR) != 0) {
				int error;

				error = ipsec_ip_input(m, false);
				if (error)
					goto bad;
			}
		}
#endif

		nxt = (*inet6sw[ip6_protox[nxt]].pr_input)(&m, &off, nxt);
	}
	return;

bad_unref:
	rtcache_unref(rt, ro);
	rtcache_percpu_putref(ip6_forward_rt_percpu);
bad:
	m_freem(m);
	return;
}

static bool
ip6_badaddr(struct ip6_hdr *ip6)
{
	/* Check against address spoofing/corruption. */
	if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
	    IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
		return true;
	}

	/*
	 * The following check is not documented in specs.  A malicious
	 * party may be able to use IPv4 mapped addr to confuse tcp/udp stack
	 * and bypass security checks (act as if it was from 127.0.0.1 by using
	 * IPv6 src ::ffff:127.0.0.1).  Be cautious.
	 *
	 * This check chokes if we are in an SIIT cloud.  As none of BSDs
	 * support IPv4-less kernel compilation, we cannot support SIIT
	 * environment at all.  So, it makes more sense for us to reject any
	 * malicious packets for non-SIIT environment, than try to do a
	 * partial support for SIIT environment.
	 */
	if (IN6_IS_ADDR_V4MAPPED(&ip6->ip6_src) ||
	    IN6_IS_ADDR_V4MAPPED(&ip6->ip6_dst)) {
		return true;
	}

	/*
	 * Reject packets with IPv4-compatible IPv6 addresses (RFC4291).
	 */
	if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
	    IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
		return true;
	}

	return false;
}

/*
 * set/grab in6_ifaddr correspond to IPv6 destination address.
 */
static struct m_tag *
ip6_setdstifaddr(struct mbuf *m, const struct in6_ifaddr *ia)
{
	struct m_tag *mtag;
	struct ip6aux *ip6a;

	mtag = ip6_addaux(m);
	if (mtag == NULL)
		return NULL;

	ip6a = (struct ip6aux *)(mtag + 1);
	if (in6_setscope(&ip6a->ip6a_src, ia->ia_ifp, &ip6a->ip6a_scope_id)) {
		IP6_STATINC(IP6_STAT_BADSCOPE);
		return NULL;
	}

	ip6a->ip6a_src = ia->ia_addr.sin6_addr;
	ip6a->ip6a_flags = ia->ia6_flags;
	return mtag;
}

const struct ip6aux *
ip6_getdstifaddr(struct mbuf *m)
{
	struct m_tag *mtag;

	mtag = ip6_findaux(m);
	if (mtag != NULL)
		return (struct ip6aux *)(mtag + 1);
	else
		return NULL;
}

/*
 * Hop-by-Hop options header processing. If a valid jumbo payload option is
 * included, the real payload length will be stored in plenp.
 *
 * rtalertp - XXX: should be stored more smart way
 */
int
ip6_hopopts_input(u_int32_t *plenp, u_int32_t *rtalertp, 
	struct mbuf **mp, int *offp)
{
	struct mbuf *m = *mp;
	int off = *offp, hbhlen;
	struct ip6_hbh *hbh;

	/* validation of the length of the header */
	IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m,
	    sizeof(struct ip6_hdr), sizeof(struct ip6_hbh));
	if (hbh == NULL) {
		IP6_STATINC(IP6_STAT_TOOSHORT);
		return -1;
	}
	hbhlen = (hbh->ip6h_len + 1) << 3;
	IP6_EXTHDR_GET(hbh, struct ip6_hbh *, m, sizeof(struct ip6_hdr),
	    hbhlen);
	if (hbh == NULL) {
		IP6_STATINC(IP6_STAT_TOOSHORT);
		return -1;
	}
	KASSERT(IP6_HDR_ALIGNED_P(hbh));
	off += hbhlen;
	hbhlen -= sizeof(struct ip6_hbh);

	if (ip6_process_hopopts(m, (u_int8_t *)hbh + sizeof(struct ip6_hbh),
	    hbhlen, rtalertp, plenp) < 0)
		return -1;

	*offp = off;
	*mp = m;
	return 0;
}

/*
 * Search header for all Hop-by-hop options and process each option.
 * This function is separate from ip6_hopopts_input() in order to
 * handle a case where the sending node itself process its hop-by-hop
 * options header. In such a case, the function is called from ip6_output().
 *
 * The function assumes that hbh header is located right after the IPv6 header
 * (RFC2460 p7), opthead is pointer into data content in m, and opthead to
 * opthead + hbhlen is located in continuous memory region.
 */
static int
ip6_process_hopopts(struct mbuf *m, u_int8_t *opthead, int hbhlen, 
	u_int32_t *rtalertp, u_int32_t *plenp)
{
	struct ip6_hdr *ip6;
	int optlen = 0;
	u_int8_t *opt = opthead;
	u_int16_t rtalert_val;
	u_int32_t jumboplen;
	const int erroff = sizeof(struct ip6_hdr) + sizeof(struct ip6_hbh);

	for (; hbhlen > 0; hbhlen -= optlen, opt += optlen) {
		switch (*opt) {
		case IP6OPT_PAD1:
			optlen = 1;
			break;
		case IP6OPT_PADN:
			if (hbhlen < IP6OPT_MINLEN) {
				IP6_STATINC(IP6_STAT_TOOSMALL);
				goto bad;
			}
			optlen = *(opt + 1) + 2;
			break;
		case IP6OPT_RTALERT:
			/* XXX may need check for alignment */
			if (hbhlen < IP6OPT_RTALERT_LEN) {
				IP6_STATINC(IP6_STAT_TOOSMALL);
				goto bad;
			}
			if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
				/* XXX stat */
				icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    erroff + opt + 1 - opthead);
				return (-1);
			}
			optlen = IP6OPT_RTALERT_LEN;
			memcpy((void *)&rtalert_val, (void *)(opt + 2), 2);
			*rtalertp = ntohs(rtalert_val);
			break;
		case IP6OPT_JUMBO:
			/* XXX may need check for alignment */
			if (hbhlen < IP6OPT_JUMBO_LEN) {
				IP6_STATINC(IP6_STAT_TOOSMALL);
				goto bad;
			}
			if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
				/* XXX stat */
				icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    erroff + opt + 1 - opthead);
				return (-1);
			}
			optlen = IP6OPT_JUMBO_LEN;

			/*
			 * IPv6 packets that have non 0 payload length
			 * must not contain a jumbo payload option.
			 */
			ip6 = mtod(m, struct ip6_hdr *);
			if (ip6->ip6_plen) {
				IP6_STATINC(IP6_STAT_BADOPTIONS);
				icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    erroff + opt - opthead);
				return (-1);
			}

			/*
			 * We may see jumbolen in unaligned location, so
			 * we'd need to perform memcpy().
			 */
			memcpy(&jumboplen, opt + 2, sizeof(jumboplen));
			jumboplen = (u_int32_t)htonl(jumboplen);

#if 1
			/*
			 * if there are multiple jumbo payload options,
			 * *plenp will be non-zero and the packet will be
			 * rejected.
			 * the behavior may need some debate in ipngwg -
			 * multiple options does not make sense, however,
			 * there's no explicit mention in specification.
			 */
			if (*plenp != 0) {
				IP6_STATINC(IP6_STAT_BADOPTIONS);
				icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    erroff + opt + 2 - opthead);
				return (-1);
			}
#endif

			/*
			 * jumbo payload length must be larger than 65535.
			 */
			if (jumboplen <= IPV6_MAXPACKET) {
				IP6_STATINC(IP6_STAT_BADOPTIONS);
				icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_HEADER,
				    erroff + opt + 2 - opthead);
				return (-1);
			}
			*plenp = jumboplen;

			break;
		default:		/* unknown option */
			if (hbhlen < IP6OPT_MINLEN) {
				IP6_STATINC(IP6_STAT_TOOSMALL);
				goto bad;
			}
			optlen = ip6_unknown_opt(opt, m,
			    erroff + opt - opthead);
			if (optlen == -1)
				return (-1);
			optlen += 2;
			break;
		}
	}

	return (0);

  bad:
	m_freem(m);
	return (-1);
}

/*
 * Unknown option processing.
 * The third argument `off' is the offset from the IPv6 header to the option,
 * which is necessary if the IPv6 header the and option header and IPv6 header
 * is not continuous in order to return an ICMPv6 error.
 */
int
ip6_unknown_opt(u_int8_t *optp, struct mbuf *m, int off)
{
	struct ip6_hdr *ip6;

	switch (IP6OPT_TYPE(*optp)) {
	case IP6OPT_TYPE_SKIP: /* ignore the option */
		return ((int)*(optp + 1));
	case IP6OPT_TYPE_DISCARD:	/* silently discard */
		m_freem(m);
		return (-1);
	case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
		IP6_STATINC(IP6_STAT_BADOPTIONS);
		icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
		return (-1);
	case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
		IP6_STATINC(IP6_STAT_BADOPTIONS);
		ip6 = mtod(m, struct ip6_hdr *);
		if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
		    (m->m_flags & (M_BCAST|M_MCAST)))
			m_freem(m);
		else
			icmp6_error(m, ICMP6_PARAM_PROB,
				    ICMP6_PARAMPROB_OPTION, off);
		return (-1);
	}

	m_freem(m);		/* XXX: NOTREACHED */
	return (-1);
}

void
ip6_savecontrol(struct in6pcb *in6p, struct mbuf **mp, 
	struct ip6_hdr *ip6, struct mbuf *m)
{
	struct socket *so = in6p->in6p_socket;
#ifdef RFC2292
#define IS2292(x, y)	((in6p->in6p_flags & IN6P_RFC2292) ? (x) : (y))
#else
#define IS2292(x, y)	(y)
#endif

	if (SOOPT_TIMESTAMP(so->so_options))
		mp = sbsavetimestamp(so->so_options, mp);

	/* some OSes call this logic with IPv4 packet, for SO_TIMESTAMP */
	if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION)
		return;

	/* RFC 2292 sec. 5 */
	if ((in6p->in6p_flags & IN6P_PKTINFO) != 0) {
		struct in6_pktinfo pi6;

		memcpy(&pi6.ipi6_addr, &ip6->ip6_dst, sizeof(struct in6_addr));
		in6_clearscope(&pi6.ipi6_addr);	/* XXX */
		pi6.ipi6_ifindex = m->m_pkthdr.rcvif_index;
		*mp = sbcreatecontrol(&pi6, sizeof(pi6),
		    IS2292(IPV6_2292PKTINFO, IPV6_PKTINFO), IPPROTO_IPV6);
		if (*mp)
			mp = &(*mp)->m_next;
	}

	if (in6p->in6p_flags & IN6P_HOPLIMIT) {
		int hlim = ip6->ip6_hlim & 0xff;

		*mp = sbcreatecontrol(&hlim, sizeof(hlim),
		    IS2292(IPV6_2292HOPLIMIT, IPV6_HOPLIMIT), IPPROTO_IPV6);
		if (*mp)
			mp = &(*mp)->m_next;
	}

	if ((in6p->in6p_flags & IN6P_TCLASS) != 0) {
		u_int32_t flowinfo;
		int tclass;

		flowinfo = (u_int32_t)ntohl(ip6->ip6_flow & IPV6_FLOWINFO_MASK);
		flowinfo >>= 20;

		tclass = flowinfo & 0xff;
		*mp = sbcreatecontrol(&tclass, sizeof(tclass),
		    IPV6_TCLASS, IPPROTO_IPV6);

		if (*mp)
			mp = &(*mp)->m_next;
	}

	/*
	 * IPV6_HOPOPTS socket option.  Recall that we required super-user
	 * privilege for the option (see ip6_ctloutput), but it might be too
	 * strict, since there might be some hop-by-hop options which can be
	 * returned to normal user.
	 * See also RFC3542 section 8 (or RFC2292 section 6).
	 */
	if ((in6p->in6p_flags & IN6P_HOPOPTS) != 0) {
		/*
		 * Check if a hop-by-hop options header is contatined in the
		 * received packet, and if so, store the options as ancillary
		 * data. Note that a hop-by-hop options header must be
		 * just after the IPv6 header, which fact is assured through
		 * the IPv6 input processing.
		 */
		struct ip6_hdr *xip6 = mtod(m, struct ip6_hdr *);
		if (xip6->ip6_nxt == IPPROTO_HOPOPTS) {
			struct ip6_hbh *hbh;
			int hbhlen;
			struct mbuf *ext;

			ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
			    xip6->ip6_nxt);
			if (ext == NULL) {
				IP6_STATINC(IP6_STAT_TOOSHORT);
				return;
			}
			hbh = mtod(ext, struct ip6_hbh *);
			hbhlen = (hbh->ip6h_len + 1) << 3;
			if (hbhlen != ext->m_len) {
				m_freem(ext);
				IP6_STATINC(IP6_STAT_TOOSHORT);
				return;
			}

			/*
			 * XXX: We copy whole the header even if a jumbo
			 * payload option is included, which option is to
			 * be removed before returning in the RFC 2292.
			 * Note: this constraint is removed in RFC3542.
			 */
			*mp = sbcreatecontrol(hbh, hbhlen,
			    IS2292(IPV6_2292HOPOPTS, IPV6_HOPOPTS),
			    IPPROTO_IPV6);
			if (*mp)
				mp = &(*mp)->m_next;
			m_freem(ext);
		}
	}

	/* IPV6_DSTOPTS and IPV6_RTHDR socket options */
	if (in6p->in6p_flags & (IN6P_DSTOPTS | IN6P_RTHDR)) {
		struct ip6_hdr *xip6 = mtod(m, struct ip6_hdr *);
		int nxt = xip6->ip6_nxt, off = sizeof(struct ip6_hdr);

		/*
		 * Search for destination options headers or routing
		 * header(s) through the header chain, and stores each
		 * header as ancillary data.
		 * Note that the order of the headers remains in
		 * the chain of ancillary data.
		 */
		for (;;) {	/* is explicit loop prevention necessary? */
			struct ip6_ext *ip6e = NULL;
			int elen;
			struct mbuf *ext = NULL;

			/*
			 * if it is not an extension header, don't try to
			 * pull it from the chain.
			 */
			switch (nxt) {
			case IPPROTO_DSTOPTS:
			case IPPROTO_ROUTING:
			case IPPROTO_HOPOPTS:
			case IPPROTO_AH: /* is it possible? */
				break;
			default:
				goto loopend;
			}

			ext = ip6_pullexthdr(m, off, nxt);
			if (ext == NULL) {
				IP6_STATINC(IP6_STAT_TOOSHORT);
				return;
			}
			ip6e = mtod(ext, struct ip6_ext *);
			if (nxt == IPPROTO_AH)
				elen = (ip6e->ip6e_len + 2) << 2;
			else
				elen = (ip6e->ip6e_len + 1) << 3;
			if (elen != ext->m_len) {
				m_freem(ext);
				IP6_STATINC(IP6_STAT_TOOSHORT);
				return;
			}
			KASSERT(IP6_HDR_ALIGNED_P(ip6e));

			switch (nxt) {
			case IPPROTO_DSTOPTS:
				if (!(in6p->in6p_flags & IN6P_DSTOPTS))
					break;

				*mp = sbcreatecontrol(ip6e, elen,
				    IS2292(IPV6_2292DSTOPTS, IPV6_DSTOPTS),
				    IPPROTO_IPV6);
				if (*mp)
					mp = &(*mp)->m_next;
				break;

			case IPPROTO_ROUTING:
				if (!(in6p->in6p_flags & IN6P_RTHDR))
					break;

				*mp = sbcreatecontrol(ip6e, elen,
				    IS2292(IPV6_2292RTHDR, IPV6_RTHDR),
				    IPPROTO_IPV6);
				if (*mp)
					mp = &(*mp)->m_next;
				break;

			case IPPROTO_HOPOPTS:
			case IPPROTO_AH: /* is it possible? */
				break;

			default:
				/*
			 	 * other cases have been filtered in the above.
				 * none will visit this case.  here we supply
				 * the code just in case (nxt overwritten or
				 * other cases).
				 */
				m_freem(ext);
				goto loopend;

			}

			/* proceed with the next header. */
			off += elen;
			nxt = ip6e->ip6e_nxt;
			ip6e = NULL;
			m_freem(ext);
			ext = NULL;
		}
	  loopend:
	  	;
	}
}
#undef IS2292


void
ip6_notify_pmtu(struct in6pcb *in6p, const struct sockaddr_in6 *dst,
    uint32_t *mtu)
{
	struct socket *so;
	struct mbuf *m_mtu;
	struct ip6_mtuinfo mtuctl;

	so = in6p->in6p_socket;

	if (mtu == NULL)
		return;

	KASSERT(so != NULL);

	memset(&mtuctl, 0, sizeof(mtuctl));	/* zero-clear for safety */
	mtuctl.ip6m_mtu = *mtu;
	mtuctl.ip6m_addr = *dst;
	if (sa6_recoverscope(&mtuctl.ip6m_addr))
		return;

	if ((m_mtu = sbcreatecontrol(&mtuctl, sizeof(mtuctl),
	    IPV6_PATHMTU, IPPROTO_IPV6)) == NULL)
		return;

	if (sbappendaddr(&so->so_rcv, (const struct sockaddr *)dst, NULL, m_mtu)
	    == 0) {
		soroverflow(so);
		m_freem(m_mtu);
	} else
		sorwakeup(so);

	return;
}

/*
 * pull single extension header from mbuf chain.  returns single mbuf that
 * contains the result, or NULL on error.
 */
static struct mbuf *
ip6_pullexthdr(struct mbuf *m, size_t off, int nxt)
{
	struct ip6_ext ip6e;
	size_t elen;
	struct mbuf *n;

	m_copydata(m, off, sizeof(ip6e), (void *)&ip6e);
	if (nxt == IPPROTO_AH)
		elen = (ip6e.ip6e_len + 2) << 2;
	else
		elen = (ip6e.ip6e_len + 1) << 3;

	MGET(n, M_DONTWAIT, MT_DATA);
	if (n && elen >= MLEN) {
		MCLGET(n, M_DONTWAIT);
		if ((n->m_flags & M_EXT) == 0) {
			m_free(n);
			n = NULL;
		}
	}
	if (!n)
		return NULL;

	n->m_len = 0;
	if (elen >= M_TRAILINGSPACE(n)) {
		m_free(n);
		return NULL;
	}

	m_copydata(m, off, elen, mtod(n, void *));
	n->m_len = elen;
	return n;
}

/*
 * Get offset to the previous header followed by the header
 * currently processed.
 */
int
ip6_get_prevhdr(struct mbuf *m, int off)
{
	struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);

	if (off == sizeof(struct ip6_hdr)) {
		return offsetof(struct ip6_hdr, ip6_nxt);
	} else if (off < sizeof(struct ip6_hdr)) {
		panic("%s: off < sizeof(struct ip6_hdr)", __func__);
	} else {
		int len, nlen, nxt;
		struct ip6_ext ip6e;

		nxt = ip6->ip6_nxt;
		len = sizeof(struct ip6_hdr);
		nlen = 0;
		while (len < off) {
			m_copydata(m, len, sizeof(ip6e), &ip6e);

			switch (nxt) {
			case IPPROTO_FRAGMENT:
				nlen = sizeof(struct ip6_frag);
				break;
			case IPPROTO_AH:
				nlen = (ip6e.ip6e_len + 2) << 2;
				break;
			default:
				nlen = (ip6e.ip6e_len + 1) << 3;
				break;
			}
			len += nlen;
			nxt = ip6e.ip6e_nxt;
		}

		return (len - nlen);
	}
}

/*
 * get next header offset.  m will be retained.
 */
int
ip6_nexthdr(struct mbuf *m, int off, int proto, int *nxtp)
{
	struct ip6_hdr ip6;
	struct ip6_ext ip6e;
	struct ip6_frag fh;

	/* just in case */
	if (m == NULL)
		panic("%s: m == NULL", __func__);
	if ((m->m_flags & M_PKTHDR) == 0 || m->m_pkthdr.len < off)
		return -1;

	switch (proto) {
	case IPPROTO_IPV6:
		/* do not chase beyond intermediate IPv6 headers */
		if (off != 0)
			return -1;
		if (m->m_pkthdr.len < off + sizeof(ip6))
			return -1;
		m_copydata(m, off, sizeof(ip6), (void *)&ip6);
		if (nxtp)
			*nxtp = ip6.ip6_nxt;
		off += sizeof(ip6);
		return off;

	case IPPROTO_FRAGMENT:
		/*
		 * terminate parsing if it is not the first fragment,
		 * it does not make sense to parse through it.
		 */
		if (m->m_pkthdr.len < off + sizeof(fh))
			return -1;
		m_copydata(m, off, sizeof(fh), (void *)&fh);
		if ((fh.ip6f_offlg & IP6F_OFF_MASK) != 0)
			return -1;
		if (nxtp)
			*nxtp = fh.ip6f_nxt;
		off += sizeof(struct ip6_frag);
		return off;

	case IPPROTO_AH:
		if (m->m_pkthdr.len < off + sizeof(ip6e))
			return -1;
		m_copydata(m, off, sizeof(ip6e), (void *)&ip6e);
		if (nxtp)
			*nxtp = ip6e.ip6e_nxt;
		off += (ip6e.ip6e_len + 2) << 2;
		if (m->m_pkthdr.len < off)
			return -1;
		return off;

	case IPPROTO_HOPOPTS:
	case IPPROTO_ROUTING:
	case IPPROTO_DSTOPTS:
		if (m->m_pkthdr.len < off + sizeof(ip6e))
			return -1;
		m_copydata(m, off, sizeof(ip6e), (void *)&ip6e);
		if (nxtp)
			*nxtp = ip6e.ip6e_nxt;
		off += (ip6e.ip6e_len + 1) << 3;
		if (m->m_pkthdr.len < off)
			return -1;
		return off;

	case IPPROTO_NONE:
	case IPPROTO_ESP:
	case IPPROTO_IPCOMP:
		/* give up */
		return -1;

	default:
		return -1;
	}
}

/*
 * get offset for the last header in the chain.  m will be kept untainted.
 */
int
ip6_lasthdr(struct mbuf *m, int off, int proto, int *nxtp)
{
	int newoff;
	int nxt;

	if (!nxtp) {
		nxt = -1;
		nxtp = &nxt;
	}
	for (;;) {
		newoff = ip6_nexthdr(m, off, proto, nxtp);
		if (newoff < 0)
			return off;
		else if (newoff < off)
			return -1;	/* invalid */
		else if (newoff == off)
			return newoff;

		off = newoff;
		proto = *nxtp;
	}
}

struct m_tag *
ip6_addaux(struct mbuf *m)
{
	struct m_tag *mtag;

	mtag = m_tag_find(m, PACKET_TAG_INET6);
	if (!mtag) {
		mtag = m_tag_get(PACKET_TAG_INET6, sizeof(struct ip6aux),
		    M_NOWAIT);
		if (mtag) {
			m_tag_prepend(m, mtag);
			memset(mtag + 1, 0, sizeof(struct ip6aux));
		}
	}
	return mtag;
}

struct m_tag *
ip6_findaux(struct mbuf *m)
{
	struct m_tag *mtag;

	mtag = m_tag_find(m, PACKET_TAG_INET6);
	return mtag;
}

void
ip6_delaux(struct mbuf *m)
{
	struct m_tag *mtag;

	mtag = m_tag_find(m, PACKET_TAG_INET6);
	if (mtag)
		m_tag_delete(m, mtag);
}

/*
 * System control for IP6
 */

const u_char inet6ctlerrmap[PRC_NCMDS] = {
	0,		0,		0,		0,
	0,		EMSGSIZE,	EHOSTDOWN,	EHOSTUNREACH,
	EHOSTUNREACH,	EHOSTUNREACH,	ECONNREFUSED,	ECONNREFUSED,
	EMSGSIZE,	EHOSTUNREACH,	0,		0,
	0,		0,		0,		0,
	ENOPROTOOPT
};

extern int sysctl_net_inet6_addrctlpolicy(SYSCTLFN_ARGS);

static int
sysctl_net_inet6_ip6_stats(SYSCTLFN_ARGS)
{

	return (NETSTAT_SYSCTL(ip6stat_percpu, IP6_NSTATS));
}

static void
sysctl_net_inet6_ip6_setup(struct sysctllog **clog)
{

	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_NODE, "inet6",
		       SYSCTL_DESCR("PF_INET6 related settings"),
		       NULL, 0, NULL, 0,
		       CTL_NET, PF_INET6, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_NODE, "ip6",
		       SYSCTL_DESCR("IPv6 related settings"),
		       NULL, 0, NULL, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6, CTL_EOL);

	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "forwarding",
		       SYSCTL_DESCR("Enable forwarding of INET6 datagrams"),
		       NULL, 0, &ip6_forwarding, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_FORWARDING, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "redirect",
		       SYSCTL_DESCR("Enable sending of ICMPv6 redirect messages"),
		       NULL, 0, &ip6_sendredirects, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_SENDREDIRECTS, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "hlim",
		       SYSCTL_DESCR("Hop limit for an INET6 datagram"),
		       NULL, 0, &ip6_defhlim, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_DEFHLIM, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "maxfragpackets",
		       SYSCTL_DESCR("Maximum number of fragments to buffer "
				    "for reassembly"),
		       NULL, 0, &ip6_maxfragpackets, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_MAXFRAGPACKETS, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "accept_rtadv",
		       SYSCTL_DESCR("Accept router advertisements"),
		       NULL, 0, &ip6_accept_rtadv, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_ACCEPT_RTADV, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "rtadv_maxroutes",
		       SYSCTL_DESCR("Maximum number of routes accepted via router advertisements"),
		       NULL, 0, &ip6_rtadv_maxroutes, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_RTADV_MAXROUTES, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_INT, "rtadv_numroutes",
		       SYSCTL_DESCR("Current number of routes accepted via router advertisements"),
		       NULL, 0, &nd6_numroutes, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_RTADV_NUMROUTES, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "keepfaith",
		       SYSCTL_DESCR("Activate faith interface"),
		       NULL, 0, &ip6_keepfaith, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_KEEPFAITH, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "log_interval",
		       SYSCTL_DESCR("Minimum interval between logging "
				    "unroutable packets"),
		       NULL, 0, &ip6_log_interval, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_LOG_INTERVAL, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "hdrnestlimit",
		       SYSCTL_DESCR("Maximum number of nested IPv6 headers"),
		       NULL, 0, &ip6_hdrnestlimit, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_HDRNESTLIMIT, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "dad_count",
		       SYSCTL_DESCR("Number of Duplicate Address Detection "
				    "probes to send"),
		       NULL, 0, &ip6_dad_count, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_DAD_COUNT, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "auto_flowlabel",
		       SYSCTL_DESCR("Assign random IPv6 flow labels"),
		       NULL, 0, &ip6_auto_flowlabel, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_AUTO_FLOWLABEL, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "defmcasthlim",
		       SYSCTL_DESCR("Default multicast hop limit"),
		       NULL, 0, &ip6_defmcasthlim, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_DEFMCASTHLIM, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_STRING, "kame_version",
		       SYSCTL_DESCR("KAME Version"),
		       NULL, 0, __UNCONST(__KAME_VERSION), 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_KAME_VERSION, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "use_deprecated",
		       SYSCTL_DESCR("Allow use of deprecated addresses as "
				    "source addresses"),
		       NULL, 0, &ip6_use_deprecated, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_USE_DEPRECATED, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "rr_prune", NULL,
		       NULL, 0, &ip6_rr_prune, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_RR_PRUNE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT
#ifndef INET6_BINDV6ONLY
		       |CTLFLAG_READWRITE,
#endif
		       CTLTYPE_INT, "v6only",
		       SYSCTL_DESCR("Disallow PF_INET6 sockets from connecting "
				    "to PF_INET sockets"),
		       NULL, 0, &ip6_v6only, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_V6ONLY, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "anonportmin",
		       SYSCTL_DESCR("Lowest ephemeral port number to assign"),
		       sysctl_net_inet_ip_ports, 0, &ip6_anonportmin, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_ANONPORTMIN, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "anonportmax",
		       SYSCTL_DESCR("Highest ephemeral port number to assign"),
		       sysctl_net_inet_ip_ports, 0, &ip6_anonportmax, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_ANONPORTMAX, CTL_EOL);
#ifndef IPNOPRIVPORTS
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "lowportmin",
		       SYSCTL_DESCR("Lowest privileged ephemeral port number "
				    "to assign"),
		       sysctl_net_inet_ip_ports, 0, &ip6_lowportmin, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_LOWPORTMIN, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "lowportmax",
		       SYSCTL_DESCR("Highest privileged ephemeral port number "
				    "to assign"),
		       sysctl_net_inet_ip_ports, 0, &ip6_lowportmax, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_LOWPORTMAX, CTL_EOL);
#endif /* IPNOPRIVPORTS */
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "auto_linklocal",
		       SYSCTL_DESCR("Default value of per-interface flag for "
		                    "adding an IPv6 link-local address to "
				    "interfaces when attached"),
		       NULL, 0, &ip6_auto_linklocal, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_AUTO_LINKLOCAL, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READONLY,
		       CTLTYPE_STRUCT, "addctlpolicy",
		       SYSCTL_DESCR("Return the current address control"
			   " policy"),
		       sysctl_net_inet6_addrctlpolicy, 0, NULL, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_ADDRCTLPOLICY, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "use_tempaddr",
		       SYSCTL_DESCR("Use temporary address"),
		       NULL, 0, &ip6_use_tempaddr, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "prefer_tempaddr",
		       SYSCTL_DESCR("Prefer temporary address as source "
		                    "address"),
		       NULL, 0, &ip6_prefer_tempaddr, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "temppltime",
		       SYSCTL_DESCR("preferred lifetime of a temporary address"),
		       NULL, 0, &ip6_temp_preferred_lifetime, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "tempvltime",
		       SYSCTL_DESCR("valid lifetime of a temporary address"),
		       NULL, 0, &ip6_temp_valid_lifetime, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "maxfrags",
		       SYSCTL_DESCR("Maximum fragments in reassembly queue"),
		       NULL, 0, &ip6_maxfrags, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_MAXFRAGS, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_STRUCT, "stats",
		       SYSCTL_DESCR("IPv6 statistics"),
		       sysctl_net_inet6_ip6_stats, 0, NULL, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_STATS, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "use_defaultzone",
		       SYSCTL_DESCR("Whether to use the default scope zones"),
		       NULL, 0, &ip6_use_defzone, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       IPV6CTL_USE_DEFAULTZONE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "mcast_pmtu",
		       SYSCTL_DESCR("Enable pMTU discovery for multicast packet"),
		       NULL, 0, &ip6_mcast_pmtu, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	/* anonportalgo RFC6056 subtree */
	const struct sysctlnode *portalgo_node;
	sysctl_createv(clog, 0, NULL, &portalgo_node,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_NODE, "anonportalgo",
		       SYSCTL_DESCR("Anonymous port algorithm selection (RFC 6056)"),
	    	       NULL, 0, NULL, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6, CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, &portalgo_node, NULL,
		       CTLFLAG_PERMANENT,
		       CTLTYPE_STRING, "available",
		       SYSCTL_DESCR("available algorithms"),
		       sysctl_portalgo_available, 0, NULL, PORTALGO_MAXLEN,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, &portalgo_node, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_STRING, "selected",
		       SYSCTL_DESCR("selected algorithm"),
	               sysctl_portalgo_selected6, 0, NULL, PORTALGO_MAXLEN,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, &portalgo_node, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_STRUCT, "reserve",
		       SYSCTL_DESCR("bitmap of reserved ports"),
		       sysctl_portalgo_reserve6, 0, NULL, 0,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "neighborgcthresh",
		       SYSCTL_DESCR("Maximum number of entries in neighbor"
			" cache"),
		       NULL, 1, &ip6_neighborgcthresh, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "maxifprefixes",
		       SYSCTL_DESCR("Maximum number of prefixes created by"
			   " route advertisement per interface"),
		       NULL, 1, &ip6_maxifprefixes, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "maxifdefrouters",
		       SYSCTL_DESCR("Maximum number of default routers created"
			   " by route advertisement per interface"),
		       NULL, 1, &ip6_maxifdefrouters, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
	sysctl_createv(clog, 0, NULL, NULL,
		       CTLFLAG_PERMANENT|CTLFLAG_READWRITE,
		       CTLTYPE_INT, "maxdynroutes",
		       SYSCTL_DESCR("Maximum number of routes created via"
			   " redirect"),
		       NULL, 1, &ip6_maxdynroutes, 0,
		       CTL_NET, PF_INET6, IPPROTO_IPV6,
		       CTL_CREATE, CTL_EOL);
}

void
ip6_statinc(u_int stat)
{

	KASSERT(stat < IP6_NSTATS);
	IP6_STATINC(stat);
}