/*      $NetBSD: in6_pcb.c,v 1.178 2026/03/01 20:42:03 andvar Exp $     */
/*      $KAME: in6_pcb.c,v 1.84 2001/02/08 18:02:08 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, 1991, 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.
 *
 *      @(#)in_pcb.c    8.2 (Berkeley) 1/4/94
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: in6_pcb.c,v 1.178 2026/03/01 20:42:03 andvar Exp $");

#ifdef _KERNEL_OPT
#include "opt_inet.h"
#include "opt_ipsec.h"
#endif

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/mbuf.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/ioctl.h>
#include <sys/errno.h>
#include <sys/time.h>
#include <sys/proc.h>
#include <sys/kauth.h>
#include <sys/domain.h>
#include <sys/once.h>

#include <net/if.h>
#include <net/route.h>

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/in_pcb.h>
#include <netinet/ip6.h>
#include <netinet/portalgo.h>
#include <netinet6/ip6_var.h>
#include <netinet6/in6_pcb.h>
#include <netinet6/scope6_var.h>

#include "faith.h"

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

#include <netinet/tcp_vtw.h>

const struct in6_addr zeroin6_addr;

#define IN6PCBHASH_PORT(table, lport) \
        &(table)->inpt_porthashtbl[ntohs(lport) & (table)->inpt_porthash]
#define IN6PCBHASH_BIND(table, laddr, lport) \
        &(table)->inpt_bindhashtbl[ \
            (((laddr)->s6_addr32[0] ^ (laddr)->s6_addr32[1] ^ \
              (laddr)->s6_addr32[2] ^ (laddr)->s6_addr32[3]) + ntohs(lport)) & \
            (table)->inpt_bindhash]
#define IN6PCBHASH_CONNECT(table, faddr, fport, laddr, lport) \
        &(table)->inpt_bindhashtbl[ \
            ((((faddr)->s6_addr32[0] ^ (faddr)->s6_addr32[1] ^ \
              (faddr)->s6_addr32[2] ^ (faddr)->s6_addr32[3]) + ntohs(fport)) + \
             (((laddr)->s6_addr32[0] ^ (laddr)->s6_addr32[1] ^ \
              (laddr)->s6_addr32[2] ^ (laddr)->s6_addr32[3]) + \
              ntohs(lport))) & (table)->inpt_bindhash]

int ip6_anonportmin = IPV6PORT_ANONMIN;
int ip6_anonportmax = IPV6PORT_ANONMAX;
int ip6_lowportmin  = IPV6PORT_RESERVEDMIN;
int ip6_lowportmax  = IPV6PORT_RESERVEDMAX;

void
in6pcb_init(struct inpcbtable *table, int bindhashsize, int connecthashsize)
{

        inpcb_init(table, bindhashsize, connecthashsize);
        table->inpt_lastport = (in_port_t)ip6_anonportmax;
}

/*
 * Bind address from sin6 to inp.
 */
static int
in6pcb_bind_addr(struct inpcb *inp, struct sockaddr_in6 *sin6, struct lwp *l)
{
        int error;
        int s;

        /*
         * We should check the family, but old programs
         * incorrectly fail to initialize it.
         */
        if (sin6->sin6_family != AF_INET6)
                return EAFNOSUPPORT;

#ifndef INET
        if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr))
                return EADDRNOTAVAIL;
#endif

        if ((error = sa6_embedscope(sin6, ip6_use_defzone)) != 0)
                return error;

        s = pserialize_read_enter();
        if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
                if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0) {
                        error = EINVAL;
                        goto out;
                }
                if (sin6->sin6_addr.s6_addr32[3]) {
                        struct sockaddr_in sin;

                        memset(&sin, 0, sizeof(sin));
                        sin.sin_len = sizeof(sin);
                        sin.sin_family = AF_INET;
                        bcopy(&sin6->sin6_addr.s6_addr32[3],
                            &sin.sin_addr, sizeof(sin.sin_addr));
                        if (!IN_MULTICAST(sin.sin_addr.s_addr)) {
                                struct ifaddr *ifa;
                                ifa = ifa_ifwithaddr((struct sockaddr *)&sin);
                                if (ifa == NULL &&
                                    (inp->inp_flags & IN6P_BINDANY) == 0) {
                                        error = EADDRNOTAVAIL;
                                        goto out;
                                }
                        }
                }
        } else if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
                // succeed
        } else if (!IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr)) {
                struct ifaddr *ifa = NULL;

                if ((inp->inp_flags & IN6P_FAITH) == 0) {
                        ifa = ifa_ifwithaddr(sin6tosa(sin6));
                        if (ifa == NULL &&
                            (inp->inp_flags & IN6P_BINDANY) == 0) {
                                error = EADDRNOTAVAIL;
                                goto out;
                        }
                }

                /*
                 * bind to an anycast address might accidentally
                 * cause sending a packet with an anycast source
                 * address, so we forbid it.
                 *
                 * We should allow to bind to a deprecated address,
                 * since the application dare to use it.
                 * But, can we assume that they are careful enough
                 * to check if the address is deprecated or not?
                 * Maybe, as a safeguard, we should have a setsockopt
                 * flag to control the bind(2) behavior against
                 * deprecated addresses (default: forbid bind(2)).
                 */
                if (ifa &&
                    ifatoia6(ifa)->ia6_flags &
                    (IN6_IFF_ANYCAST | IN6_IFF_DUPLICATED)) {
                        error = EADDRNOTAVAIL;
                        goto out;
                }
        }
        in6p_laddr(inp) = sin6->sin6_addr;
        error = 0;
out:
        pserialize_read_exit(s);
        return error;
}

/*
 * Bind port from sin6 to inp.
 */
static int
in6pcb_bind_port(struct inpcb *inp, struct sockaddr_in6 *sin6, struct lwp *l)
{
        struct inpcbtable *table = inp->inp_table;
        struct socket *so = inp->inp_socket;
        int wild = 0, reuseport = (so->so_options & SO_REUSEPORT);
        int error;

        if ((so->so_options & (SO_REUSEADDR|SO_REUSEPORT)) == 0 &&
           ((so->so_proto->pr_flags & PR_CONNREQUIRED) == 0 ||
            (so->so_options & SO_ACCEPTCONN) == 0))
                wild = 1;

        if (sin6->sin6_port != 0) {
                enum kauth_network_req req;

#ifndef IPNOPRIVPORTS
                if (ntohs(sin6->sin6_port) < IPV6PORT_RESERVED)
                        req = KAUTH_REQ_NETWORK_BIND_PRIVPORT;
                else
#endif /* IPNOPRIVPORTS */
                        req = KAUTH_REQ_NETWORK_BIND_PORT;

                error = kauth_authorize_network(l->l_cred, KAUTH_NETWORK_BIND,
                    req, so, sin6, NULL);
                if (error)
                        return EACCES;
        }

        if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr)) {
                /*
                 * Treat SO_REUSEADDR as SO_REUSEPORT for multicast;
                 * allow complete duplication of binding if
                 * SO_REUSEPORT is set, or if SO_REUSEADDR is set
                 * and a multicast address is bound on both
                 * new and duplicated sockets.
                 */
                if (so->so_options & (SO_REUSEADDR | SO_REUSEPORT))
                        reuseport = SO_REUSEADDR|SO_REUSEPORT;
        }

        if (sin6->sin6_port != 0) {
                if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
#ifdef INET
                        struct inpcb *t;
                        struct vestigial_inpcb vestige;

                        t = inpcb_lookup_local(table,
                            *(struct in_addr *)&sin6->sin6_addr.s6_addr32[3],
                            sin6->sin6_port, wild, &vestige);
                        if (t && (reuseport & t->inp_socket->so_options) == 0)
                                return EADDRINUSE;
                        if (!t
                            && vestige.valid
                            && !(reuseport && vestige.reuse_port))
                            return EADDRINUSE;
#else
                        return EADDRNOTAVAIL;
#endif
                }

                {
                        struct inpcb *t;
                        struct vestigial_inpcb vestige;

                        t = in6pcb_lookup_local(table, &sin6->sin6_addr,
                            sin6->sin6_port, wild, &vestige);
                        if (t && (reuseport & t->inp_socket->so_options) == 0)
                                return EADDRINUSE;
                        if (!t
                            && vestige.valid
                            && !(reuseport && vestige.reuse_port))
                            return EADDRINUSE;
                }
        }

        if (sin6->sin6_port == 0) {
                int e;
                e = in6pcb_set_port(sin6, inp, l);
                if (e != 0)
                        return e;
        } else {
                inp->inp_lport = sin6->sin6_port;
                inpcb_set_state(inp, INP_BOUND);
        }

        LIST_REMOVE(inp, inp_lhash);
        LIST_INSERT_HEAD(IN6PCBHASH_PORT(table, inp->inp_lport),
            inp, inp_lhash);

        return 0;
}

int
in6pcb_bind(void *v, struct sockaddr_in6 *sin6, struct lwp *l)
{
        struct inpcb *inp = v;
        struct sockaddr_in6 lsin6;
        int error;

        if (inp->inp_af != AF_INET6)
                return EINVAL;

        /*
         * If we already have a local port or a local address it means we're
         * bounded.
         */
        if (inp->inp_lport || !(IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)) ||
            (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)) &&
              in6p_laddr(inp).s6_addr32[3] == 0)))
                return EINVAL;

        if (NULL != sin6) {
                /* We were provided a sockaddr_in6 to use. */
                if (sin6->sin6_len != sizeof(*sin6))
                        return EINVAL;
        } else {
                /* We always bind to *something*, even if it's "anything". */
                lsin6 = *((const struct sockaddr_in6 *)
                    inp->inp_socket->so_proto->pr_domain->dom_sa_any);
                sin6 = &lsin6;
        }

        /* Bind address. */
        error = in6pcb_bind_addr(inp, sin6, l);
        if (error)
                return error;

        /* Bind port. */
        error = in6pcb_bind_port(inp, sin6, l);
        if (error) {
                /*
                 * Reset the address here to "any" so we don't "leak" the
                 * inpcb.
                 */
                in6p_laddr(inp) = in6addr_any;

                return error;
        }


#if 0
        in6p_flowinfo(inp) = 0; /* XXX */
#endif
        return 0;
}

/*
 * Connect from a socket to a specified address.
 * Both address and port must be specified in argument sin6.
 * If don't have a local address for this socket yet,
 * then pick one.
 */
int
in6pcb_connect(void *v, struct sockaddr_in6 *sin6, struct lwp *l)
{
        struct inpcb *inp = v;
        struct in6_addr *in6a = NULL;
        struct in6_addr ia6;
        struct ifnet *ifp = NULL;       /* outgoing interface */
        int error = 0;
        int scope_ambiguous = 0;
#ifdef INET
        struct in6_addr mapped;
#endif
        struct sockaddr_in6 tmp;
        struct vestigial_inpcb vestige;
        struct psref psref;
        int bound;

        (void)&in6a;                            /* XXX fool gcc */

        if (inp->inp_af != AF_INET6)
                return EINVAL;

        if (sin6->sin6_len != sizeof(*sin6))
                return EINVAL;
        if (sin6->sin6_family != AF_INET6)
                return EAFNOSUPPORT;
        if (sin6->sin6_port == 0)
                return EADDRNOTAVAIL;

        if (IN6_IS_ADDR_MULTICAST(&sin6->sin6_addr) &&
            inp->inp_socket->so_type == SOCK_STREAM)
                return EADDRNOTAVAIL;

        if (sin6->sin6_scope_id == 0 && !ip6_use_defzone)
                scope_ambiguous = 1;
        if ((error = sa6_embedscope(sin6, ip6_use_defzone)) != 0)
                return error;

        /* sanity check for mapped address case */
        if (IN6_IS_ADDR_V4MAPPED(&sin6->sin6_addr)) {
                if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                        return EINVAL;
                if (IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)))
                        in6p_laddr(inp).s6_addr16[5] = htons(0xffff);
                if (!IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)))
                        return EINVAL;
        } else
        {
                if (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)))
                        return EINVAL;
        }

        /* protect *sin6 from overwrites */
        tmp = *sin6;
        sin6 = &tmp;

        bound = curlwp_bind();
        /* Source address selection. */
        if (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)) &&
            in6p_laddr(inp).s6_addr32[3] == 0) {
#ifdef INET
                struct sockaddr_in sin;
                struct in_ifaddr *ia4;
                struct psref _psref;

                memset(&sin, 0, sizeof(sin));
                sin.sin_len = sizeof(sin);
                sin.sin_family = AF_INET;
                memcpy(&sin.sin_addr, &sin6->sin6_addr.s6_addr32[3],
                        sizeof(sin.sin_addr));
                ia4 = in_selectsrc(&sin, &inp->inp_route,
                        inp->inp_socket->so_options, NULL, &error, &_psref);
                if (ia4 == NULL) {
                        if (error == 0)
                                error = EADDRNOTAVAIL;
                        curlwp_bindx(bound);
                        return error;
                }
                memset(&mapped, 0, sizeof(mapped));
                mapped.s6_addr16[5] = htons(0xffff);
                memcpy(&mapped.s6_addr32[3], &IA_SIN(ia4)->sin_addr,
                    sizeof(IA_SIN(ia4)->sin_addr));
                ia4_release(ia4, &_psref);
                in6a = &mapped;
#else
                curlwp_bindx(bound);
                return EADDRNOTAVAIL;
#endif
        } else {
                /*
                 * XXX: in6_selectsrc might replace the bound local address
                 * with the address specified by setsockopt(IPV6_PKTINFO).
                 * Is it the intended behavior?
                 */
                error = in6_selectsrc(sin6, in6p_outputopts(inp),
                    in6p_moptions(inp), &inp->inp_route, &in6p_laddr(inp),
                    &ifp, &psref, &ia6);
                if (error == 0)
                        in6a = &ia6;
                if (ifp && scope_ambiguous &&
                    (error = in6_setscope(&sin6->sin6_addr, ifp, NULL)) != 0) {
                        if_put(ifp, &psref);
                        curlwp_bindx(bound);
                        return error;
                }

                if (in6a == NULL) {
                        if_put(ifp, &psref);
                        curlwp_bindx(bound);
                        if (error == 0)
                                error = EADDRNOTAVAIL;
                        return error;
                }
        }

        if (ifp != NULL) {
                in6p_ip6(inp).ip6_hlim = (u_int8_t)in6pcb_selecthlim(inp, ifp);
                if_put(ifp, &psref);
        } else
                in6p_ip6(inp).ip6_hlim = (u_int8_t)in6pcb_selecthlim_rt(inp);
        curlwp_bindx(bound);

        if (in6pcb_lookup(inp->inp_table, &sin6->sin6_addr,
            sin6->sin6_port,
            IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)) ? in6a : &in6p_laddr(inp),
                                  inp->inp_lport, 0, &vestige)
                || vestige.valid)
                return EADDRINUSE;
        if (IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)) ||
            (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp)) &&
             in6p_laddr(inp).s6_addr32[3] == 0))
        {
                if (inp->inp_lport == 0) {
                        error = in6pcb_bind(inp, NULL, l);
                        if (error != 0)
                                return error;
                }
                in6p_laddr(inp) = *in6a;
        }
        in6p_faddr(inp) = sin6->sin6_addr;
        inp->inp_fport = sin6->sin6_port;

        /* Late bind, if needed */
        if (inp->inp_bindportonsend) {
               struct sockaddr_in6 lsin = *((const struct sockaddr_in6 *)
                    inp->inp_socket->so_proto->pr_domain->dom_sa_any);
                lsin.sin6_addr = in6p_laddr(inp);
                lsin.sin6_port = 0;

               if ((error = in6pcb_bind_port(inp, &lsin, l)) != 0)
                       return error;
        }
        
        inpcb_set_state(inp, INP_CONNECTED);
        in6p_flowinfo(inp) &= ~IPV6_FLOWLABEL_MASK;
        if (ip6_auto_flowlabel)
                in6p_flowinfo(inp) |=
                    (htonl(ip6_randomflowlabel()) & IPV6_FLOWLABEL_MASK);
#if defined(IPSEC)
        if (ipsec_enabled && inp->inp_socket->so_type == SOCK_STREAM)
                ipsec_pcbconn(inp->inp_sp);
#endif
        return 0;
}

void
in6pcb_disconnect(struct inpcb *inp)
{
        memset((void *)&in6p_faddr(inp), 0, sizeof(in6p_faddr(inp)));
        inp->inp_fport = 0;
        inpcb_set_state(inp, INP_BOUND);
        in6p_flowinfo(inp) &= ~IPV6_FLOWLABEL_MASK;
#if defined(IPSEC)
        if (ipsec_enabled)
                ipsec_pcbdisconn(inp->inp_sp);
#endif
        if (inp->inp_socket->so_state & SS_NOFDREF)
                inpcb_destroy(inp);
}

void
in6pcb_fetch_sockaddr(struct inpcb *inp, struct sockaddr_in6 *sin6)
{

        if (inp->inp_af != AF_INET6)
                return;

        sockaddr_in6_init(sin6, &in6p_laddr(inp), inp->inp_lport, 0, 0);
        (void)sa6_recoverscope(sin6); /* XXX: should catch errors */
}

void
in6pcb_fetch_peeraddr(struct inpcb *inp, struct sockaddr_in6 *sin6)
{

        if (inp->inp_af != AF_INET6)
                return;

        sockaddr_in6_init(sin6, &in6p_faddr(inp), inp->inp_fport, 0, 0);
        (void)sa6_recoverscope(sin6); /* XXX: should catch errors */
}

/*
 * Pass some notification to all connections of a protocol
 * associated with address dst.  The local address and/or port numbers
 * may be specified to limit the search.  The "usual action" will be
 * taken, depending on the ctlinput cmd.  The caller must filter any
 * cmds that are uninteresting (e.g., no error in the map).
 * Call the protocol specific routine (if any) to report
 * any errors for each matching socket.
 *
 * Must be called at splsoftnet.
 *
 * Note: src (4th arg) carries the flowlabel value on the original IPv6
 * header, in sin6_flowinfo member.
 */
int
in6pcb_notify(struct inpcbtable *table, const struct sockaddr *dst,
    u_int fport_arg, const struct sockaddr *src, u_int lport_arg, int cmd,
    void *cmdarg, void (*notify)(struct inpcb *, int))
{
        struct inpcb *inp;
        struct sockaddr_in6 sa6_src;
        const struct sockaddr_in6 *sa6_dst;
        in_port_t fport = fport_arg, lport = lport_arg;
        int errno;
        int nmatch = 0;
        u_int32_t flowinfo;

        if ((unsigned)cmd >= PRC_NCMDS || dst->sa_family != AF_INET6)
                return 0;

        sa6_dst = (const struct sockaddr_in6 *)dst;
        if (IN6_IS_ADDR_UNSPECIFIED(&sa6_dst->sin6_addr))
                return 0;

        /*
         * note that src can be NULL when we get notify by local fragmentation.
         */
        sa6_src = (src == NULL) ? sa6_any : *(const struct sockaddr_in6 *)src;
        flowinfo = sa6_src.sin6_flowinfo;

        /*
         * Redirects go to all references to the destination,
         * and use in6pcb_rtchange to invalidate the route cache.
         * Dead host indications: also use in6pcb_rtchange to invalidate
         * the cache, and deliver the error to all the sockets.
         * Otherwise, if we have knowledge of the local port and address,
         * deliver only to that socket.
         */
        if (PRC_IS_REDIRECT(cmd) || cmd == PRC_HOSTDEAD) {
                fport = 0;
                lport = 0;
                memset((void *)&sa6_src.sin6_addr, 0, sizeof(sa6_src.sin6_addr));

                if (cmd != PRC_HOSTDEAD)
                        notify = in6pcb_rtchange;
        }

        errno = inet6ctlerrmap[cmd];
        TAILQ_FOREACH(inp, &table->inpt_queue, inp_queue) {
                struct rtentry *rt = NULL;

                if (inp->inp_af != AF_INET6)
                        continue;

                /*
                 * Under the following condition, notify of redirects
                 * to the pcb, without making address matches against inpcb.
                 * - redirect notification is arrived.
                 * - the inpcb is unconnected.
                 * - the inpcb is caching !RTF_HOST routing entry.
                 * - the ICMPv6 notification is from the gateway cached in the
                 *   inpcb.  i.e. ICMPv6 notification is from nexthop gateway
                 *   the inpcb used very recently.
                 *
                 * This is to improve interaction between netbsd/openbsd
                 * redirect handling code, and inpcb route cache code.
                 * without the clause, !RTF_HOST routing entry (which carries
                 * gateway used by inpcb right before the ICMPv6 redirect)
                 * will be cached forever in unconnected inpcb.
                 *
                 * There still is a question regarding to what is TRT:
                 * - On bsdi/freebsd, RTF_HOST (cloned) routing entry will be
                 *   generated on packet output.  inpcb will always cache
                 *   RTF_HOST routing entry so there's no need for the clause
                 *   (ICMPv6 redirect will update RTF_HOST routing entry,
                 *   and inpcb is caching it already).
                 *   However, bsdi/freebsd are vulnerable to local DoS attacks
                 *   due to the cloned routing entries.
                 * - Specwise, "destination cache" is mentioned in RFC2461.
                 *   Jinmei says that it implies bsdi/freebsd behavior, itojun
                 *   is not really convinced.
                 * - Having hiwat/lowat on # of cloned host route (redirect/
                 *   pmtud) may be a good idea.  netbsd/openbsd has it.  see
                 *   icmp6_mtudisc_update().
                 */
                if ((PRC_IS_REDIRECT(cmd) || cmd == PRC_HOSTDEAD) &&
                    IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)) &&
                    (rt = rtcache_validate(&inp->inp_route)) != NULL &&
                    !(rt->rt_flags & RTF_HOST)) {
                        const struct sockaddr_in6 *dst6;

                        dst6 = (const struct sockaddr_in6 *)
                            rtcache_getdst(&inp->inp_route);
                        if (dst6 == NULL)
                                ;
                        else if (IN6_ARE_ADDR_EQUAL(&dst6->sin6_addr,
                            &sa6_dst->sin6_addr)) {
                                rtcache_unref(rt, &inp->inp_route);
                                goto do_notify;
                        }
                }
                rtcache_unref(rt, &inp->inp_route);

                /*
                 * If the error designates a new path MTU for a destination
                 * and the application (associated with this socket) wanted to
                 * know the value, notify. Note that we notify for all
                 * disconnected sockets if the corresponding application
                 * wanted. This is because some UDP applications keep sending
                 * sockets disconnected.
                 * XXX: should we avoid to notify the value to TCP sockets?
                 */
                if (cmd == PRC_MSGSIZE && (inp->inp_flags & IN6P_MTU) != 0 &&
                    (IN6_IS_ADDR_UNSPECIFIED(&in6p_faddr(inp)) ||
                     IN6_ARE_ADDR_EQUAL(&in6p_faddr(inp), &sa6_dst->sin6_addr))) {
                        ip6_notify_pmtu(inp, (const struct sockaddr_in6 *)dst,
                                        (u_int32_t *)cmdarg);
                }

                /*
                 * Detect if we should notify the error. If no source and
                 * destination ports are specified, but non-zero flowinfo and
                 * local address match, notify the error. This is the case
                 * when the error is delivered with an encrypted buffer
                 * by ESP. Otherwise, just compare addresses and ports
                 * as usual.
                 */
                if (lport == 0 && fport == 0 && flowinfo &&
                    inp->inp_socket != NULL &&
                    flowinfo == (in6p_flowinfo(inp) & IPV6_FLOWLABEL_MASK) &&
                    IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp), &sa6_src.sin6_addr))
                        goto do_notify;
                else if (!IN6_ARE_ADDR_EQUAL(&in6p_faddr(inp),
                                             &sa6_dst->sin6_addr) ||
                    inp->inp_socket == NULL ||
                    (lport && inp->inp_lport != lport) ||
                    (!IN6_IS_ADDR_UNSPECIFIED(&sa6_src.sin6_addr) &&
                     !IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp),
                                         &sa6_src.sin6_addr)) ||
                    (fport && inp->inp_fport != fport))
                        continue;

          do_notify:
                if (notify)
                        (*notify)(inp, errno);
                nmatch++;
        }
        return nmatch;
}

void
in6pcb_purgeif0(struct inpcbtable *table, struct ifnet *ifp)
{
        struct inpcb *inp;
        struct ip6_moptions *im6o;
        struct in6_multi_mship *imm, *nimm;

        KASSERT(ifp != NULL);

        TAILQ_FOREACH(inp, &table->inpt_queue, inp_queue) {
                bool need_unlock = false;
                if (inp->inp_af != AF_INET6)
                        continue;

                /* The caller holds either one of inps' lock */
                if (!inp_locked(inp)) {
                        inp_lock(inp);
                        need_unlock = true;
                }
                im6o = in6p_moptions(inp);
                if (im6o) {
                        /*
                         * Unselect the outgoing interface if it is being
                         * detached.
                         */
                        if (im6o->im6o_multicast_if_index == ifp->if_index)
                                im6o->im6o_multicast_if_index = 0;

                        /*
                         * Drop multicast group membership if we joined
                         * through the interface being detached.
                         * XXX controversial - is it really legal for kernel
                         * to force this?
                         */
                        LIST_FOREACH_SAFE(imm, &im6o->im6o_memberships,
                            i6mm_chain, nimm) {
                                if (imm->i6mm_maddr->in6m_ifp == ifp) {
                                        LIST_REMOVE(imm, i6mm_chain);
                                        in6_leavegroup(imm);
                                }
                        }
                }

                in_purgeifmcast(inp->inp_moptions, ifp);

                if (need_unlock)
                        inp_unlock(inp);
        }
}

void
in6pcb_purgeif(struct inpcbtable *table, struct ifnet *ifp)
{
        struct rtentry *rt;
        struct inpcb *inp;

        TAILQ_FOREACH(inp, &table->inpt_queue, inp_queue) {
                if (inp->inp_af != AF_INET6)
                        continue;
                if ((rt = rtcache_validate(&inp->inp_route)) != NULL &&
                    rt->rt_ifp == ifp) {
                        rtcache_unref(rt, &inp->inp_route);
                        in6pcb_rtchange(inp, 0);
                } else
                        rtcache_unref(rt, &inp->inp_route);
        }
}

/*
 * After a routing change, flush old routing.  A new route can be
 * allocated the next time output is attempted.
 */
void
in6pcb_rtchange(struct inpcb *inp, int errno)
{
        if (inp->inp_af != AF_INET6)
                return;

        rtcache_free(&inp->inp_route);
        /*
         * A new route can be allocated the next time
         * output is attempted.
         */
}

struct inpcb *
in6pcb_lookup_local(struct inpcbtable *table, struct in6_addr *laddr6, 
                   u_int lport_arg, int lookup_wildcard, struct vestigial_inpcb *vp)
{
        struct inpcbhead *head;
        struct inpcb *inp, *match = NULL;
        int matchwild = 3, wildcard;
        in_port_t lport = lport_arg;

        if (vp)
                vp->valid = 0;

        head = IN6PCBHASH_PORT(table, lport);
        LIST_FOREACH(inp, head, inp_lhash) {
                if (inp->inp_af != AF_INET6)
                        continue;

                if (inp->inp_lport != lport)
                        continue;
                wildcard = 0;
                if (IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp))) {
                        if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                                continue;
                }
                if (!IN6_IS_ADDR_UNSPECIFIED(&in6p_faddr(inp)))
                        wildcard++;
                if (IN6_IS_ADDR_V4MAPPED(&in6p_laddr(inp))) {
                        if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                                continue;
                        if (!IN6_IS_ADDR_V4MAPPED(laddr6))
                                continue;

                        /* duplicate of IPv4 logic */
                        wildcard = 0;
                        if (IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp)) &&
                            in6p_faddr(inp).s6_addr32[3])
                                wildcard++;
                        if (!in6p_laddr(inp).s6_addr32[3]) {
                                if (laddr6->s6_addr32[3])
                                        wildcard++;
                        } else {
                                if (!laddr6->s6_addr32[3])
                                        wildcard++;
                                else {
                                        if (in6p_laddr(inp).s6_addr32[3] !=
                                            laddr6->s6_addr32[3])
                                                continue;
                                }
                        }
                } else if (IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp))) {
                        if (IN6_IS_ADDR_V4MAPPED(laddr6)) {
                                if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                                        continue;
                        }
                        if (!IN6_IS_ADDR_UNSPECIFIED(laddr6))
                                wildcard++;
                } else {
                        if (IN6_IS_ADDR_V4MAPPED(laddr6)) {
                                if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                                        continue;
                        }
                        if (IN6_IS_ADDR_UNSPECIFIED(laddr6))
                                wildcard++;
                        else {
                                if (!IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp),
                                    laddr6))
                                        continue;
                        }
                }
                if (wildcard && !lookup_wildcard)
                        continue;
                if (wildcard < matchwild) {
                        match = inp;
                        matchwild = wildcard;
                        if (matchwild == 0)
                                break;
                }
        }
        if (match && matchwild == 0)
                return match;

        if (vp && table->vestige && table->vestige->init_ports6) {
                struct vestigial_inpcb better;
                bool has_better = false;
                void *state;

                state = (*table->vestige->init_ports6)(laddr6,
                                                       lport_arg,
                                                       lookup_wildcard);
                while (table->vestige
                       && (*table->vestige->next_port6)(state, vp)) {

                        if (vp->lport != lport)
                                continue;
                        wildcard = 0;
                        if (!IN6_IS_ADDR_UNSPECIFIED(&vp->faddr.v6))
                                wildcard++;
                        if (IN6_IS_ADDR_UNSPECIFIED(&vp->laddr.v6)) {
                                if (!IN6_IS_ADDR_UNSPECIFIED(laddr6))
                                        wildcard++;
                        } else {
                                if (IN6_IS_ADDR_V4MAPPED(laddr6)) {
                                        if (vp->v6only)
                                                continue;
                                }
                                if (IN6_IS_ADDR_UNSPECIFIED(laddr6))
                                        wildcard++;
                                else {
                                        if (!IN6_ARE_ADDR_EQUAL(&vp->laddr.v6, laddr6))
                                                continue;
                                }
                        }
                        if (wildcard && !lookup_wildcard)
                                continue;
                        if (wildcard < matchwild) {
                                better = *vp;
                                has_better = true;

                                matchwild = wildcard;
                                if (matchwild == 0)
                                        break;
                        }
                }

                if (has_better) {
                        *vp = better;
                        return 0;
                }
        }
        return match;
}

/*
 * WARNING: return value (rtentry) could be IPv4 one if inpcb is connected to
 * IPv4 mapped address.
 */
struct rtentry *
in6pcb_rtentry(struct inpcb *inp)
{
        struct rtentry *rt;
        struct route *ro;
        union {
                const struct sockaddr *sa;
                const struct sockaddr_in6 *sa6;
#ifdef INET
                const struct sockaddr_in *sa4;
#endif
        } cdst;

        ro = &inp->inp_route;

        if (inp->inp_af != AF_INET6)
                return NULL;

        cdst.sa = rtcache_getdst(ro);
        if (cdst.sa == NULL)
                ;
#ifdef INET
        else if (cdst.sa->sa_family == AF_INET) {
                KASSERT(IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp)));
                if (cdst.sa4->sin_addr.s_addr != in6p_faddr(inp).s6_addr32[3])
                        rtcache_free(ro);
        }
#endif
        else {
                if (!IN6_ARE_ADDR_EQUAL(&cdst.sa6->sin6_addr,
                                        &in6p_faddr(inp)))
                        rtcache_free(ro);
        }
        if ((rt = rtcache_validate(ro)) == NULL)
                rt = rtcache_update(ro, 1);
#ifdef INET
        if (rt == NULL && IN6_IS_ADDR_V4MAPPED(&in6p_faddr(inp))) {
                union {
                        struct sockaddr         dst;
                        struct sockaddr_in      dst4;
                } u;
                struct in_addr addr;

                addr.s_addr = in6p_faddr(inp).s6_addr32[3];

                sockaddr_in_init(&u.dst4, &addr, 0);
                if (rtcache_setdst(ro, &u.dst) != 0)
                        return NULL;

                rt = rtcache_init(ro);
        } else
#endif
        if (rt == NULL && !IN6_IS_ADDR_UNSPECIFIED(&in6p_faddr(inp))) {
                union {
                        struct sockaddr         dst;
                        struct sockaddr_in6     dst6;
                } u;

                sockaddr_in6_init(&u.dst6, &in6p_faddr(inp), 0, 0, 0);
                if (rtcache_setdst(ro, &u.dst) != 0)
                        return NULL;

                rt = rtcache_init(ro);
        }
        return rt;
}

void
in6pcb_rtentry_unref(struct rtentry *rt, struct inpcb *inp)
{

        rtcache_unref(rt, &inp->inp_route);
}

struct inpcb *
in6pcb_lookup(struct inpcbtable *table, const struct in6_addr *faddr6,
                      u_int fport_arg, const struct in6_addr *laddr6, u_int lport_arg,
                      int faith,
                      struct vestigial_inpcb *vp)
{
        struct inpcbhead *head;
        struct inpcb *inp;
        in_port_t fport = fport_arg, lport = lport_arg;

        if (vp)
                vp->valid = 0;

        head = IN6PCBHASH_CONNECT(table, faddr6, fport, laddr6, lport);
        LIST_FOREACH(inp, head, inp_hash) {
                if (inp->inp_af != AF_INET6)
                        continue;

                /* find exact match on both source and dest */
                if (inp->inp_fport != fport)
                        continue;
                if (inp->inp_lport != lport)
                        continue;
                if (IN6_IS_ADDR_UNSPECIFIED(&in6p_faddr(inp)))
                        continue;
                if (!IN6_ARE_ADDR_EQUAL(&in6p_faddr(inp), faddr6))
                        continue;
                if (IN6_IS_ADDR_UNSPECIFIED(&in6p_laddr(inp)))
                        continue;
                if (!IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp), laddr6))
                        continue;
                if ((IN6_IS_ADDR_V4MAPPED(laddr6) ||
                     IN6_IS_ADDR_V4MAPPED(faddr6)) &&
                    (inp->inp_flags & IN6P_IPV6_V6ONLY))
                        continue;
                return inp;
        }
        if (vp && table->vestige) {
                if ((*table->vestige->lookup6)(faddr6, fport_arg,
                                               laddr6, lport_arg, vp))
                        return NULL;
        }

        return NULL;
}

struct inpcb *
in6pcb_lookup_bound(struct inpcbtable *table, const struct in6_addr *laddr6, 
        u_int lport_arg, int faith)
{
        struct inpcbhead *head;
        struct inpcb *inp;
        in_port_t lport = lport_arg;
#ifdef INET
        struct in6_addr zero_mapped;
#endif

        head = IN6PCBHASH_BIND(table, laddr6, lport);
        LIST_FOREACH(inp, head, inp_hash) {
                if (inp->inp_af != AF_INET6)
                        continue;

                if (faith && (inp->inp_flags & IN6P_FAITH) == 0)
                        continue;
                if (inp->inp_fport != 0)
                        continue;
                if (inp->inp_lport != lport)
                        continue;
                if (IN6_IS_ADDR_V4MAPPED(laddr6) &&
                    (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                        continue;
                if (IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp), laddr6))
                        goto out;
        }
#ifdef INET
        if (IN6_IS_ADDR_V4MAPPED(laddr6)) {
                memset(&zero_mapped, 0, sizeof(zero_mapped));
                zero_mapped.s6_addr16[5] = 0xffff;
                head = IN6PCBHASH_BIND(table, &zero_mapped, lport);
                LIST_FOREACH(inp, head, inp_hash) {
                        if (inp->inp_af != AF_INET6)
                                continue;

                        if (faith && (inp->inp_flags & IN6P_FAITH) == 0)
                                continue;
                        if (inp->inp_fport != 0)
                                continue;
                        if (inp->inp_lport != lport)
                                continue;
                        if ((inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                                continue;
                        if (IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp), &zero_mapped))
                                goto out;
                }
        }
#endif
        head = IN6PCBHASH_BIND(table, &zeroin6_addr, lport);
        LIST_FOREACH(inp, head, inp_hash) {
                if (inp->inp_af != AF_INET6)
                        continue;

                if (faith && (inp->inp_flags & IN6P_FAITH) == 0)
                        continue;
                if (inp->inp_fport != 0)
                        continue;
                if (inp->inp_lport != lport)
                        continue;
                if (IN6_IS_ADDR_V4MAPPED(laddr6) &&
                    (inp->inp_flags & IN6P_IPV6_V6ONLY) != 0)
                        continue;
                if (IN6_ARE_ADDR_EQUAL(&in6p_laddr(inp), &zeroin6_addr))
                        goto out;
        }
        return NULL;

out:
        if (inp != LIST_FIRST(head)) {
                LIST_REMOVE(inp, inp_hash);
                LIST_INSERT_HEAD(head, inp, inp_hash);
        }
        return inp;
}

void
in6pcb_set_state(struct inpcb *inp, int state)
{

        if (inp->inp_af != AF_INET6)
                return;

        if (inp->inp_state > INP_ATTACHED)
                LIST_REMOVE(inp, inp_hash);

        switch (state) {
        case INP_BOUND:
                LIST_INSERT_HEAD(IN6PCBHASH_BIND(inp->inp_table,
                    &in6p_laddr(inp), inp->inp_lport), inp,
                    inp_hash);
                break;
        case INP_CONNECTED:
                LIST_INSERT_HEAD(IN6PCBHASH_CONNECT(inp->inp_table,
                    &in6p_faddr(inp), inp->inp_fport,
                    &in6p_laddr(inp), inp->inp_lport), inp,
                    inp_hash);
                break;
        }

        inp->inp_state = state;
}