/*      $OpenBSD: ip6_input.c,v 1.300 2025/09/16 09:19:16 florian 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 "pf.h"
#include "carp.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/domain.h>
#include <sys/sysctl.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/task.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_types.h>
#include <net/route.h>
#include <net/netisr.h>

#include <netinet/in.h>

#include <netinet/ip.h>

#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet6/in6_var.h>
#include <netinet/ip6.h>
#include <netinet6/ip6_var.h>
#include <netinet/icmp6.h>
#include <netinet6/nd6.h>

#ifdef MROUTING
#include <netinet6/ip6_mroute.h>
#endif

#if NPF > 0
#include <net/pfvar.h>
#endif

#if NCARP > 0
#include <netinet/ip_carp.h>
#endif

struct niqueue ip6intrq = NIQUEUE_INITIALIZER(IPQ_MAXLEN, NETISR_IPV6);

struct cpumem *ip6counters;

int ip6_ours(struct mbuf **, int *, int, int, int, struct netstack *);
int ip6_check_rh0hdr(struct mbuf *, int *);
int ip6_hbhchcheck(struct mbuf **, int *, int *, int);
int ip6_hopopts_input(struct mbuf **, int *, u_int32_t *, u_int32_t *);
struct mbuf *ip6_pullexthdr(struct mbuf *, size_t, int);

static struct mbuf_queue        ip6send_mq;

static void ip6_send_dispatch(void *);
static struct task ip6send_task =
        TASK_INITIALIZER(ip6_send_dispatch, &ip6send_mq);

/*
 * 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 protosw *pr;
        int i;

        pr = pffindproto(PF_INET6, IPPROTO_RAW, SOCK_RAW);
        if (pr == NULL)
                panic("%s", __func__);
        for (i = 0; i < IPPROTO_MAX; i++)
                ip6_protox[i] = pr - inet6sw;
        for (pr = inet6domain.dom_protosw;
            pr < inet6domain.dom_protoswNPROTOSW; pr++)
                if (pr->pr_domain->dom_family == PF_INET6 &&
                    pr->pr_protocol && pr->pr_protocol != IPPROTO_RAW &&
                    pr->pr_protocol < IPPROTO_MAX)
                        ip6_protox[pr->pr_protocol] = pr - inet6sw;
        ip6_randomid_init();
        nd6_init();
        frag6_init();

        mq_init(&ip6send_mq, 64, IPL_SOFTNET);

        ip6counters = counters_alloc(ip6s_ncounters);
#ifdef MROUTING
        mrt6_init();
#endif
}

/*
 * Enqueue packet for local delivery.  Queuing is used as a boundary
 * between the network layer (input/forward path) running with
 * NET_LOCK_SHARED() and the transport layer needing it exclusively.
 */
int
ip6_ours(struct mbuf **mp, int *offp, int nxt, int af, int flags,
    struct netstack *ns)
{
        /* ip6_hbhchcheck() may be run before, then off and nxt are set */
        if (*offp == 0) {
                nxt = ip6_hbhchcheck(mp, offp, NULL, flags);
                if (nxt == IPPROTO_DONE)
                        return IPPROTO_DONE;
        }

        /* We are already in a IPv4/IPv6 local deliver loop. */
        if (af != AF_UNSPEC)
                return nxt;

        nxt = ip_deliver(mp, offp, nxt, AF_INET6, 1, ns);
        if (nxt == IPPROTO_DONE)
                return IPPROTO_DONE;

        return ip6_ours_enqueue(mp, offp, nxt);
}

int
ip6_ours_enqueue(struct mbuf **mp, int *offp, int nxt)
{
        /* save values for later, use after dequeue */
        if (*offp != sizeof(struct ip6_hdr)) {
                struct m_tag *mtag;
                struct ipoffnxt *ion;

                /* mbuf tags are expensive, but only used for header options */
                mtag = m_tag_get(PACKET_TAG_IP6_OFFNXT, sizeof(*ion),
                    M_NOWAIT);
                if (mtag == NULL) {
                        ip6stat_inc(ip6s_idropped);
                        m_freemp(mp);
                        return IPPROTO_DONE;
                }
                ion = (struct ipoffnxt *)(mtag + 1);
                ion->ion_off = *offp;
                ion->ion_nxt = nxt;

                m_tag_prepend(*mp, mtag);
        }

        niq_enqueue(&ip6intrq, *mp);
        *mp = NULL;
        return IPPROTO_DONE;
}

/*
 * Dequeue and process locally delivered packets.
 * This is called with exclusive NET_LOCK().
 */
void
ip6intr(void)
{
        struct mbuf *m;

        while ((m = niq_dequeue(&ip6intrq)) != NULL) {
                struct m_tag *mtag;
                int off, nxt;

#ifdef DIAGNOSTIC
                if ((m->m_flags & M_PKTHDR) == 0)
                        panic("ip6intr no HDR");
#endif
                mtag = m_tag_find(m, PACKET_TAG_IP6_OFFNXT, NULL);
                if (mtag != NULL) {
                        struct ipoffnxt *ion;

                        ion = (struct ipoffnxt *)(mtag + 1);
                        off = ion->ion_off;
                        nxt = ion->ion_nxt;

                        m_tag_delete(m, mtag);
                } else {
                        struct ip6_hdr *ip6;

                        ip6 = mtod(m, struct ip6_hdr *);
                        off = sizeof(struct ip6_hdr);
                        nxt = ip6->ip6_nxt;
                }
                nxt = ip_deliver(&m, &off, nxt, AF_INET6, 0, NULL);
                KASSERT(nxt == IPPROTO_DONE);
        }
}

void
ipv6_input(struct ifnet *ifp, struct mbuf *m, struct netstack *ns)
{
        int off, nxt;

        off = 0;
        nxt = ip6_input_if(&m, &off, IPPROTO_IPV6, AF_UNSPEC, ifp, ns);
        KASSERT(nxt == IPPROTO_DONE);
}

struct mbuf *
ipv6_check(struct ifnet *ifp, struct mbuf *m)
{
        struct ip6_hdr *ip6;

        if (m->m_len < sizeof(*ip6)) {
                m = m_pullup(m, sizeof(*ip6));
                if (m == NULL) {
                        ip6stat_inc(ip6s_toosmall);
                        return (NULL);
                }
        }

        ip6 = mtod(m, struct ip6_hdr *);

        if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION) {
                ip6stat_inc(ip6s_badvers);
                goto bad;
        }

        /*
         * Check against address spoofing/corruption.
         */
        if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_src) ||
            IN6_IS_ADDR_UNSPECIFIED(&ip6->ip6_dst)) {
                /*
                 * XXX: "badscope" is not very suitable for a multicast source.
                 */
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }
        if ((IN6_IS_ADDR_LOOPBACK(&ip6->ip6_src) ||
            IN6_IS_ADDR_LOOPBACK(&ip6->ip6_dst)) &&
            (ifp->if_flags & IFF_LOOPBACK) == 0) {
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }
        /* Drop packets if interface ID portion is already filled. */
        if (((IN6_IS_SCOPE_EMBED(&ip6->ip6_src) && ip6->ip6_src.s6_addr16[1]) ||
            (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst) && ip6->ip6_dst.s6_addr16[1])) &&
            (ifp->if_flags & IFF_LOOPBACK) == 0) {
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }
        if (IN6_IS_ADDR_MC_INTFACELOCAL(&ip6->ip6_dst) &&
            !(m->m_flags & M_LOOP)) {
                /*
                 * In this case, the packet should come from the loopback
                 * interface.  However, we cannot just check the if_flags,
                 * because ip6_mloopback() passes the "actual" interface
                 * as the outgoing/incoming interface.
                 */
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }

        /*
         * 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)) {
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }

        /*
         * Reject packets with IPv4 compatible addresses (auto tunnel).
         *
         * The code forbids automatic tunneling as per RFC4213.
         */
        if (IN6_IS_ADDR_V4COMPAT(&ip6->ip6_src) ||
            IN6_IS_ADDR_V4COMPAT(&ip6->ip6_dst)) {
                ip6stat_inc(ip6s_badscope);
                goto bad;
        }

        return (m);
bad:
        m_freem(m);
        return (NULL);
}

int
ip6_input_if(struct mbuf **mp, int *offp, int nxt, int af, struct ifnet *ifp,
    struct netstack *ns)
{
        struct route iproute, *ro = NULL;
        struct mbuf *m;
        struct ip6_hdr *ip6;
        struct rtentry *rt;
        int ours = 0;
        u_int16_t src_scope, dst_scope;
#if NPF > 0
        struct in6_addr odst;
#endif
        int flags = 0;

        KASSERT(*offp == 0);

        ip6stat_inc(ip6s_total);
        m = *mp = ipv6_check(ifp, *mp);
        if (m == NULL)
                goto bad;

        ip6 = mtod(m, struct ip6_hdr *);

#if NCARP > 0
        if (carp_lsdrop(ifp, m, AF_INET6, ip6->ip6_src.s6_addr32,
            ip6->ip6_dst.s6_addr32, (ip6->ip6_nxt == IPPROTO_ICMPV6 ? 0 : 1)))
                goto bad;
#endif
        ip6stat_inc(ip6s_nxthist + ip6->ip6_nxt);

        /*
         * If the packet has been received on a loopback interface it
         * can be destined to any local address, not necessarily to
         * an address configured on `ifp'.
         */
        if (ifp->if_flags & IFF_LOOPBACK) {
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src)) {
                        src_scope = ip6->ip6_src.s6_addr16[1];
                        ip6->ip6_src.s6_addr16[1] = 0;
                }
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst)) {
                        dst_scope = ip6->ip6_dst.s6_addr16[1];
                        ip6->ip6_dst.s6_addr16[1] = 0;
                }
        }

#if NPF > 0
        /*
         * Packet filter
         */
        odst = ip6->ip6_dst;
        if (pf_test(AF_INET6, PF_IN, ifp, mp) != PF_PASS)
                goto bad;
        m = *mp;
        if (m == NULL)
                goto bad;

        ip6 = mtod(m, struct ip6_hdr *);
        if (!IN6_ARE_ADDR_EQUAL(&odst, &ip6->ip6_dst))
                SET(flags, IPV6_REDIRECT);
#endif

        switch (atomic_load_int(&ip6_forwarding)) {
        case 2:
                SET(flags, IPV6_FORWARDING_IPSEC);
                /* FALLTHROUGH */
        case 1:
                SET(flags, IPV6_FORWARDING);
                break;
        }

        /*
         * Without embedded scope ID we cannot find link-local
         * addresses in the routing table.
         */
        if (ifp->if_flags & IFF_LOOPBACK) {
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
                        ip6->ip6_src.s6_addr16[1] = src_scope;
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
                        ip6->ip6_dst.s6_addr16[1] = dst_scope;
        } else {
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_src))
                        ip6->ip6_src.s6_addr16[1] = htons(ifp->if_index);
                if (IN6_IS_SCOPE_EMBED(&ip6->ip6_dst))
                        ip6->ip6_dst.s6_addr16[1] = htons(ifp->if_index);
        }

        /*
         * Be more secure than RFC5095 and scan for type 0 routing headers.
         * If pf has already scanned the header chain, do not do it twice.
         */
        if (!(m->m_pkthdr.pf.flags & PF_TAG_PROCESSED) &&
            ip6_check_rh0hdr(m, offp)) {
                ip6stat_inc(ip6s_badoptions);
                icmp6_error(m, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_HEADER, *offp);
                m = *mp = NULL;
                goto bad;
        }

#if NPF > 0
        if (pf_ouraddr(m) == 1) {
                nxt = ip6_ours(mp, offp, nxt, af, flags, ns);
                goto out;
        }
#endif

        /*
         * Multicast check
         */
        if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst)) {
                /*
                 * Make sure M_MCAST is set.  It should theoretically
                 * already be there, but let's play safe because upper
                 * layers check for this flag.
                 */
                m->m_flags |= M_MCAST;

                /*
                 * See if we belong to the destination multicast group on the
                 * arrival interface.
                 */
                if (in6_hasmulti(&ip6->ip6_dst, ifp))
                        ours = 1;

#ifdef MROUTING
                if (atomic_load_int(&ip6_mforwarding) &&
                    ip6_mrouter[ifp->if_rdomain]) {
                        int error;

                        nxt = ip6_hbhchcheck(&m, offp, &ours, flags);
                        if (nxt == IPPROTO_DONE)
                                goto out;

                        ip6 = mtod(m, struct ip6_hdr *);

                        /*
                         * 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.
                         */
                        KERNEL_LOCK();
                        error = ip6_mforward(ip6, ifp, m, flags);
                        KERNEL_UNLOCK();
                        if (error) {
                                ip6stat_inc(ip6s_cantforward);
                                goto bad;
                        }

                        if (ours) {
                                if (af == AF_UNSPEC)
                                        nxt = ip6_ours(mp, offp, nxt, af,
                                            flags, ns);
                                goto out;
                        }
                        goto bad;
                }
#endif
                if (!ours) {
                        ip6stat_inc(ip6s_notmember);
                        if (!IN6_IS_ADDR_MC_LINKLOCAL(&ip6->ip6_dst))
                                ip6stat_inc(ip6s_cantforward);
                        goto bad;
                }
                nxt = ip6_ours(mp, offp, nxt, af, flags, ns);
                goto out;
        }


        /*
         *  Unicast check
         */
        if (ns == NULL) {
                ro = &iproute;
                ro->ro_rt = NULL;
        } else {
                ro = &ns->ns_route;
        }
        rt = route6_mpath(ro, &ip6->ip6_dst, &ip6->ip6_src,
            m->m_pkthdr.ph_rtableid);

        /*
         * Accept the packet if the route to the destination is marked
         * as local.
         */
        if (rt != NULL && ISSET(rt->rt_flags, RTF_LOCAL)) {
                struct in6_ifaddr *ia6 = ifatoia6(rt->rt_ifa);

                if (!ISSET(flags, IPV6_FORWARDING) &&
                    rt->rt_ifidx != ifp->if_index &&
                    !((ifp->if_flags & IFF_LOOPBACK) ||
                    (ifp->if_type == IFT_ENC) ||
                    (m->m_pkthdr.pf.flags & PF_TAG_TRANSLATE_LOCALHOST))) {
                        /* received on wrong interface */
#if NCARP > 0
                        struct ifnet *out_if;

                        /*
                         * Virtual IPs on carp interfaces need to be checked
                         * also against the parent interface and other carp
                         * interfaces sharing the same parent.
                         */
                        out_if = if_get(rt->rt_ifidx);
                        if (!(out_if && carp_strict_addr_chk(out_if, ifp))) {
                                ip6stat_inc(ip6s_wrongif);
                                if_put(out_if);
                                goto bad;
                        }
                        if_put(out_if);
#else
                        ip6stat_inc(ip6s_wrongif);
                        goto bad;
#endif
                }
                /*
                 * packets to a tentative, duplicated, or somehow invalid
                 * address must not be accepted.
                 */
                if ((ia6->ia6_flags & (IN6_IFF_TENTATIVE|IN6_IFF_DUPLICATED)))
                        goto bad;
                else {
                        nxt = ip6_ours(mp, offp, nxt, af, flags, ns);
                        goto out;
                }
        }

#if NCARP > 0
        if (ip6->ip6_nxt == IPPROTO_ICMPV6 &&
            carp_lsdrop(ifp, m, AF_INET6, ip6->ip6_src.s6_addr32,
            ip6->ip6_dst.s6_addr32, 1))
                goto bad;
#endif
        /*
         * Now there is no reason to process the packet if it's not our own
         * and we're not a router.
         */
        if (!ISSET(flags, IPV6_FORWARDING)) {
                ip6stat_inc(ip6s_cantforward);
                goto bad;
        }

        nxt = ip6_hbhchcheck(&m, offp, &ours, flags);
        if (nxt == IPPROTO_DONE)
                goto out;

        if (ours) {
                if (af == AF_UNSPEC)
                        nxt = ip6_ours(mp, offp, nxt, af, flags, ns);
                goto out;
        }

#ifdef IPSEC
        if (ipsec_in_use) {
                int rv;

                rv = ipsec_forward_check(m, *offp, AF_INET6);
                if (rv != 0) {
                        ip6stat_inc(ip6s_cantforward);
                        goto bad;
                }
                /*
                 * Fall through, forward packet. Outbound IPsec policy
                 * checking will occur in ip6_forward().
                 */
        }
#endif /* IPSEC */

        ip6_forward(m, ro, flags);
        *mp = NULL;
        if (ro == &iproute)
                rtfree(ro->ro_rt);
        return IPPROTO_DONE;
 bad:
        nxt = IPPROTO_DONE;
        m_freemp(mp);
 out:
        if (ro == &iproute)
                rtfree(ro->ro_rt);
        return nxt;
}

/* On error free mbuf and return IPPROTO_DONE. */
int
ip6_hbhchcheck(struct mbuf **mp, int *offp, int *oursp, int flags)
{
        struct ip6_hdr *ip6;
        u_int32_t plen, rtalert = ~0;
        int nxt;

        ip6 = mtod(*mp, struct ip6_hdr *);

        /*
         * 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);
        *offp = sizeof(struct ip6_hdr);
        if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
                struct ip6_hbh *hbh;

                if (ip6_hopopts_input(mp, offp, &plen, &rtalert))
                        goto bad;       /* m have already been freed */

                /* adjust pointer */
                ip6 = mtod(*mp, 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.
                         */
                        ip6stat_inc(ip6s_badoptions);
                        icmp6_error(*mp, ICMP6_PARAM_PROB,
                                    ICMP6_PARAMPROB_HEADER,
                                    (caddr_t)&ip6->ip6_plen - (caddr_t)ip6);
                        goto bad;
                }
                hbh = ip6_exthdr_get(mp, sizeof(struct ip6_hdr),
                    sizeof(struct ip6_hbh));
                if (hbh == NULL) {
                        ip6stat_inc(ip6s_tooshort);
                        goto bad;
                }
                nxt = hbh->ip6h_nxt;

                /*
                 * accept the packet if a router alert option is included
                 * and we act as an IPv6 router.
                 */
                if (rtalert != ~0 && ISSET(flags, IPV6_FORWARDING) &&
                    oursp != NULL)
                        *oursp = 1;
        } else
                nxt = ip6->ip6_nxt;

        /*
         * Check that the amount of data in the buffers
         * is as 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 ((*mp)->m_pkthdr.len - sizeof(struct ip6_hdr) < plen) {
                ip6stat_inc(ip6s_tooshort);
                m_freemp(mp);
                goto bad;
        }
        if ((*mp)->m_pkthdr.len > sizeof(struct ip6_hdr) + plen) {
                if ((*mp)->m_len == (*mp)->m_pkthdr.len) {
                        (*mp)->m_len = sizeof(struct ip6_hdr) + plen;
                        (*mp)->m_pkthdr.len = sizeof(struct ip6_hdr) + plen;
                } else {
                        m_adj((*mp), sizeof(struct ip6_hdr) + plen -
                            (*mp)->m_pkthdr.len);
                }
        }

        return nxt;
 bad:
        return IPPROTO_DONE;
}

/* scan packet for RH0 routing header. Mostly stolen from pf.c:pf_test() */
int
ip6_check_rh0hdr(struct mbuf *m, int *offp)
{
        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
        struct ip6_rthdr rthdr;
        struct ip6_ext opt6;
        u_int8_t proto = ip6->ip6_nxt;
        int done = 0, lim, off, rh_cnt = 0;

        off = ((caddr_t)ip6 - m->m_data) + sizeof(struct ip6_hdr);
        lim = min(m->m_pkthdr.len, ntohs(ip6->ip6_plen) + sizeof(*ip6));
        do {
                switch (proto) {
                case IPPROTO_ROUTING:
                        if (rh_cnt++) {
                                /* more than one rh header present */
                                *offp = off;
                                return (1);
                        }

                        if (off + sizeof(rthdr) > lim) {
                                /* packet to short to make sense */
                                *offp = off;
                                return (1);
                        }

                        m_copydata(m, off, sizeof(rthdr), &rthdr);

                        if (rthdr.ip6r_type == IPV6_RTHDR_TYPE_0) {
                                *offp = off +
                                    offsetof(struct ip6_rthdr, ip6r_type);
                                return (1);
                        }

                        off += (rthdr.ip6r_len + 1) * 8;
                        proto = rthdr.ip6r_nxt;
                        break;
                case IPPROTO_AH:
                case IPPROTO_HOPOPTS:
                case IPPROTO_DSTOPTS:
                        /* get next header and header length */
                        if (off + sizeof(opt6) > lim) {
                                /*
                                 * Packet to short to make sense, we could
                                 * reject the packet but as a router we
                                 * should not do that so forward it.
                                 */
                                return (0);
                        }

                        m_copydata(m, off, sizeof(opt6), &opt6);

                        if (proto == IPPROTO_AH)
                                off += (opt6.ip6e_len + 2) * 4;
                        else
                                off += (opt6.ip6e_len + 1) * 8;
                        proto = opt6.ip6e_nxt;
                        break;
                case IPPROTO_FRAGMENT:
                default:
                        /* end of header stack */
                        done = 1;
                        break;
                }
        } while (!done);

        return (0);
}

/*
 * Hop-by-Hop options header processing. If a valid jumbo payload option is
 * included, the real payload length will be stored in plenp.
 * On error free mbuf and return -1.
 *
 * rtalertp - XXX: should be stored in a more smart way
 */
int
ip6_hopopts_input(struct mbuf **mp, int *offp, u_int32_t *plenp,
    u_int32_t *rtalertp)
{
        int off = *offp, hbhlen;
        struct ip6_hbh *hbh;

        /* validation of the length of the header */
        hbh = ip6_exthdr_get(mp, sizeof(struct ip6_hdr),
            sizeof(struct ip6_hbh));
        if (hbh == NULL) {
                ip6stat_inc(ip6s_tooshort);
                return -1;
        }
        hbhlen = (hbh->ip6h_len + 1) << 3;
        hbh = ip6_exthdr_get(mp, sizeof(struct ip6_hdr), hbhlen);
        if (hbh == NULL) {
                ip6stat_inc(ip6s_tooshort);
                return -1;
        }
        off += hbhlen;
        hbhlen -= sizeof(struct ip6_hbh);

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

        *offp = off;
        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().
 * On error free mbuf and return -1.
 *
 * 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.
 */
int
ip6_process_hopopts(struct mbuf **mp, 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) {
                                ip6stat_inc(ip6s_toosmall);
                                goto bad;
                        }
                        optlen = *(opt + 1) + 2;
                        break;
                case IP6OPT_ROUTER_ALERT:
                        /* XXX may need check for alignment */
                        if (hbhlen < IP6OPT_RTALERT_LEN) {
                                ip6stat_inc(ip6s_toosmall);
                                goto bad;
                        }
                        if (*(opt + 1) != IP6OPT_RTALERT_LEN - 2) {
                                /* XXX stat */
                                icmp6_error(*mp, ICMP6_PARAM_PROB,
                                    ICMP6_PARAMPROB_HEADER,
                                    erroff + opt + 1 - opthead);
                                return (-1);
                        }
                        optlen = IP6OPT_RTALERT_LEN;
                        memcpy((caddr_t)&rtalert_val, (caddr_t)(opt + 2), 2);
                        *rtalertp = ntohs(rtalert_val);
                        break;
                case IP6OPT_JUMBO:
                        /* XXX may need check for alignment */
                        if (hbhlen < IP6OPT_JUMBO_LEN) {
                                ip6stat_inc(ip6s_toosmall);
                                goto bad;
                        }
                        if (*(opt + 1) != IP6OPT_JUMBO_LEN - 2) {
                                /* XXX stat */
                                icmp6_error(*mp, 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(*mp, struct ip6_hdr *);
                        if (ip6->ip6_plen) {
                                ip6stat_inc(ip6s_badoptions);
                                icmp6_error(*mp, 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) {
                                ip6stat_inc(ip6s_badoptions);
                                icmp6_error(*mp, 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) {
                                ip6stat_inc(ip6s_badoptions);
                                icmp6_error(*mp, ICMP6_PARAM_PROB,
                                    ICMP6_PARAMPROB_HEADER,
                                    erroff + opt + 2 - opthead);
                                return (-1);
                        }
                        *plenp = jumboplen;

                        break;
                default:                /* unknown option */
                        if (hbhlen < IP6OPT_MINLEN) {
                                ip6stat_inc(ip6s_toosmall);
                                goto bad;
                        }
                        optlen = ip6_unknown_opt(mp, opt,
                            erroff + opt - opthead);
                        if (optlen == -1)
                                return (-1);
                        optlen += 2;
                        break;
                }
        }

        return (0);

  bad:
        m_freemp(mp);
        return (-1);
}

/*
 * Unknown option processing.
 * The third argument `off' is the offset from the IPv6 header to the option,
 * which allows returning an ICMPv6 error even if the IPv6 header and the
 * option header are not continuous.
 * On error free mbuf and return -1.
 */
int
ip6_unknown_opt(struct mbuf **mp, u_int8_t *optp, 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_freemp(mp);
                return (-1);
        case IP6OPT_TYPE_FORCEICMP: /* send ICMP even if multicasted */
                ip6stat_inc(ip6s_badoptions);
                icmp6_error(*mp, ICMP6_PARAM_PROB, ICMP6_PARAMPROB_OPTION, off);
                return (-1);
        case IP6OPT_TYPE_ICMP: /* send ICMP if not multicasted */
                ip6stat_inc(ip6s_badoptions);
                ip6 = mtod(*mp, struct ip6_hdr *);
                if (IN6_IS_ADDR_MULTICAST(&ip6->ip6_dst) ||
                    ((*mp)->m_flags & (M_BCAST|M_MCAST)))
                        m_freemp(mp);
                else
                        icmp6_error(*mp, ICMP6_PARAM_PROB,
                                    ICMP6_PARAMPROB_OPTION, off);
                return (-1);
        }

        m_freemp(mp);           /* XXX: NOTREACHED */
        return (-1);
}

/*
 * Create the "control" list for this pcb.
 *
 * The routine will be called from upper layer handlers like udp_input().
 * Thus the routine assumes that the caller (udp_input) have already
 * called IP6_EXTHDR_CHECK() and all the extension headers are located in the
 * very first mbuf on the mbuf chain.
 * We may want to add some infinite loop prevention or sanity checks for safety.
 * (This applies only when you are using KAME mbuf chain restriction, i.e.
 * you are using IP6_EXTHDR_CHECK() not m_pulldown())
 */
void
ip6_savecontrol(struct inpcb *inp, struct mbuf *m, struct mbuf **mp)
{
        struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);

        if (inp->inp_socket->so_options & SO_TIMESTAMP) {
                struct timeval tv;

                m_microtime(m, &tv);
                *mp = sbcreatecontrol((caddr_t) &tv, sizeof(tv),
                    SCM_TIMESTAMP, SOL_SOCKET);
                if (*mp)
                        mp = &(*mp)->m_next;
        }

        /* RFC 2292 sec. 5 */
        if ((inp->inp_flags & IN6P_PKTINFO) != 0) {
                struct in6_pktinfo pi6;
                memcpy(&pi6.ipi6_addr, &ip6->ip6_dst, sizeof(struct in6_addr));
                if (IN6_IS_SCOPE_EMBED(&pi6.ipi6_addr))
                        pi6.ipi6_addr.s6_addr16[1] = 0;
                pi6.ipi6_ifindex = m ? m->m_pkthdr.ph_ifidx : 0;
                *mp = sbcreatecontrol((caddr_t) &pi6,
                    sizeof(struct in6_pktinfo),
                    IPV6_PKTINFO, IPPROTO_IPV6);
                if (*mp)
                        mp = &(*mp)->m_next;
        }

        if ((inp->inp_flags & IN6P_HOPLIMIT) != 0) {
                int hlim = ip6->ip6_hlim & 0xff;
                *mp = sbcreatecontrol((caddr_t) &hlim, sizeof(int),
                    IPV6_HOPLIMIT, IPPROTO_IPV6);
                if (*mp)
                        mp = &(*mp)->m_next;
        }

        if ((inp->inp_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((caddr_t)&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 RFC 2292 section 6 (or RFC 3542 section 8).
         */
        if ((inp->inp_flags & IN6P_HOPOPTS) != 0) {
                /*
                 * Check if a hop-by-hop options header is contained 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 is assured through the
                 * IPv6 input processing.
                 */
                struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
                if (ip6->ip6_nxt == IPPROTO_HOPOPTS) {
                        struct ip6_hbh *hbh;
                        int hbhlen = 0;
                        struct mbuf *ext;

                        ext = ip6_pullexthdr(m, sizeof(struct ip6_hdr),
                            ip6->ip6_nxt);
                        if (ext == NULL) {
                                ip6stat_inc(ip6s_tooshort);
                                return;
                        }
                        hbh = mtod(ext, struct ip6_hbh *);
                        hbhlen = (hbh->ip6h_len + 1) << 3;
                        if (hbhlen != ext->m_len) {
                                m_freem(ext);
                                ip6stat_inc(ip6s_tooshort);
                                return;
                        }

                        /*
                         * XXX: We copy the whole header even if a
                         * jumbo payload option is included, the option which
                         * is to be removed before returning according to
                         * RFC2292.
                         * Note: this constraint is removed in RFC3542.
                         */
                        *mp = sbcreatecontrol((caddr_t)hbh, hbhlen,
                            IPV6_HOPOPTS,
                            IPPROTO_IPV6);
                        if (*mp)
                                mp = &(*mp)->m_next;
                        m_freem(ext);
                }
        }

        /* IPV6_DSTOPTS and IPV6_RTHDR socket options */
        if ((inp->inp_flags & (IN6P_RTHDR | IN6P_DSTOPTS)) != 0) {
                struct ip6_hdr *ip6 = mtod(m, struct ip6_hdr *);
                int nxt = ip6->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.
                 */
                while (1) {     /* 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) {
                                ip6stat_inc(ip6s_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);
                                ip6stat_inc(ip6s_tooshort);
                                return;
                        }

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

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

                        case IPPROTO_ROUTING:
                                if (!(inp->inp_flags & IN6P_RTHDR))
                                        break;

                                *mp = sbcreatecontrol((caddr_t)ip6e, elen,
                                    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:
                ;
        }
}

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

#ifdef DIAGNOSTIC
        switch (nxt) {
        case IPPROTO_DSTOPTS:
        case IPPROTO_ROUTING:
        case IPPROTO_HOPOPTS:
        case IPPROTO_AH: /* is it possible? */
                break;
        default:
                printf("ip6_pullexthdr: invalid nxt=%d\n", nxt);
        }
#endif

        if (off + sizeof(ip6e) > m->m_pkthdr.len)
                return NULL;

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

        if (off + elen > m->m_pkthdr.len)
                return NULL;

        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 == NULL) {
                ip6stat_inc(ip6s_idropped);
                return NULL;
        }

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

        m_copydata(m, off, elen, mtod(n, caddr_t));
        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:
                if (m->m_pkthdr.len < off + sizeof(ip6))
                        return -1;
                m_copydata(m, off, sizeof(ip6), &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), &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), &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), &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;
        }

        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;
        }
        while (1) {
                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;
        }
}

/*
 * 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
};

#ifdef MROUTING
extern int ip6_mrtproto;
#endif

#ifndef SMALL_KERNEL
const struct sysctl_bounded_args ipv6ctl_vars[] = {
        { IPV6CTL_FORWARDING, &ip6_forwarding, 0, 2 },
        { IPV6CTL_SENDREDIRECTS, &ip6_sendredirects, 0, 1 },
        { IPV6CTL_DAD_PENDING, &ip6_dad_pending, SYSCTL_INT_READONLY },
#ifdef MROUTING
        { IPV6CTL_MRTPROTO, &ip6_mrtproto, SYSCTL_INT_READONLY },
#endif
        { IPV6CTL_DEFHLIM, &ip6_defhlim, 0, 255 },
        { IPV6CTL_MAXFRAGPACKETS, &ip6_maxfragpackets, 0, 1000 },
        { IPV6CTL_HDRNESTLIMIT, &ip6_hdrnestlimit, 0, 100 },
        { IPV6CTL_DAD_COUNT, &ip6_dad_count, 0, 10 },
        { IPV6CTL_DEFMCASTHLIM, &ip6_defmcasthlim, 0, 255 },
        { IPV6CTL_MAXFRAGS, &ip6_maxfrags, 0, 1000 },
        { IPV6CTL_MFORWARDING, &ip6_mforwarding, 0, 1 },
        { IPV6CTL_MCAST_PMTU, &ip6_mcast_pmtu, 0, 1 },
        { IPV6CTL_NEIGHBORGCTHRESH, &ip6_neighborgcthresh, 0, 5 * 2048 },
        { IPV6CTL_MAXDYNROUTES, &ip6_maxdynroutes, 0, 5 * 4096 },
};

int
ip6_sysctl_ip6stat(void *oldp, size_t *oldlenp, void *newp)
{
        struct ip6stat *ip6stat;
        int ret;

        CTASSERT(sizeof(*ip6stat) == (ip6s_ncounters * sizeof(uint64_t)));

        ip6stat = malloc(sizeof(*ip6stat), M_TEMP, M_WAITOK);
        counters_read(ip6counters, (uint64_t *)ip6stat, ip6s_ncounters, NULL);
        ret = sysctl_rdstruct(oldp, oldlenp, newp,
            ip6stat, sizeof(*ip6stat));
        free(ip6stat, M_TEMP, sizeof(*ip6stat));

        return (ret);
}
#endif /* SMALL_KERNEL */

int
ip6_sysctl(int *name, u_int namelen, void *oldp, size_t *oldlenp,
    void *newp, size_t newlen)
{
        /* Almost all sysctl names at this level are terminal. */
        if (namelen != 1 && name[0] != IPV6CTL_IFQUEUE)
                return (ENOTDIR);

        switch (name[0]) {
#ifndef SMALL_KERNEL
        case IPV6CTL_STATS:
                return (ip6_sysctl_ip6stat(oldp, oldlenp, newp));
#ifdef MROUTING
        case IPV6CTL_MRTSTATS:
                return mrt6_sysctl_mrt6stat(oldp, oldlenp, newp);
        case IPV6CTL_MRTMIF:
                if (newp)
                        return (EPERM);
                return (mrt6_sysctl_mif(oldp, oldlenp));
        case IPV6CTL_MRTMFC:
                if (newp)
                        return (EPERM);
                return (mrt6_sysctl_mfc(oldp, oldlenp));
#else
        case IPV6CTL_MRTSTATS:
        case IPV6CTL_MRTPROTO:
        case IPV6CTL_MRTMIF:
        case IPV6CTL_MRTMFC:
                return (EOPNOTSUPP);
#endif
        case IPV6CTL_MTUDISCTIMEOUT: {
                int oldval, newval, error;

                oldval = newval = atomic_load_int(&ip6_mtudisc_timeout);
                error = sysctl_int_bounded(oldp, oldlenp, newp, newlen,
                    &newval, 0, INT_MAX);
                if (error == 0 && oldval != newval) {
                        rw_enter_write(&sysctl_lock);
                        atomic_store_int(&ip6_mtudisc_timeout, newval);
                        rt_timer_queue_change(&icmp6_mtudisc_timeout_q, newval);
                        rw_exit_write(&sysctl_lock);
                }

                return (error);
        }
        case IPV6CTL_IFQUEUE:
                return (sysctl_niq(name + 1, namelen - 1,
                    oldp, oldlenp, newp, newlen, &ip6intrq));
        case IPV6CTL_MULTIPATH: {
                int oldval, newval, error;

                oldval = newval = atomic_load_int(&ip6_multipath);
                error = sysctl_int_bounded(oldp, oldlenp, newp, newlen,
                    &newval, 0, 1);
                if (error == 0 && oldval != newval) {
                        atomic_store_int(&ip6_multipath, newval);
                        membar_producer();
                        atomic_inc_long(&rtgeneration);
                }

                return (error);
        }
        default:
                return (sysctl_bounded_arr(ipv6ctl_vars, nitems(ipv6ctl_vars),
                    name, namelen, oldp, oldlenp, newp, newlen));
#else
        default:
                return (EOPNOTSUPP);
#endif /* SMALL_KERNEL */
        }
        /* NOTREACHED */
}

void
ip6_send_dispatch(void *xmq)
{
        struct mbuf_queue *mq = xmq;
        struct mbuf *m;
        struct mbuf_list ml;

        mq_delist(mq, &ml);
        if (ml_empty(&ml))
                return;

        NET_LOCK_SHARED();
        while ((m = ml_dequeue(&ml)) != NULL) {
                ip6_output(m, NULL, NULL, 0, NULL, NULL);
        }
        NET_UNLOCK_SHARED();
}

void
ip6_send(struct mbuf *m)
{
        mq_enqueue(&ip6send_mq, m);
        task_add(net_tq(0), &ip6send_task);
}