/*      $OpenBSD: in.c,v 1.194 2026/03/22 23:14:00 bluhm Exp $  */
/*      $NetBSD: in.c,v 1.26 1996/02/13 23:41:39 christos Exp $ */

/*
 * Copyright (C) 2001 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.c        8.2 (Berkeley) 11/15/93
 */

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/ioctl.h>
#include <sys/malloc.h>
#include <sys/socket.h>
#include <sys/socketvar.h>

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

#include <netinet/in.h>
#include <netinet/in_var.h>
#include <netinet/igmp_var.h>

#ifdef MROUTING
#include <netinet/ip_mroute.h>
#endif

void in_socktrim(struct sockaddr_in *);

int in_ioctl_set_ifaddr(u_long, caddr_t, struct ifnet *);
int in_ioctl_change_ifaddr(u_long, caddr_t, struct ifnet *);
int in_ioctl_get(u_long, caddr_t, struct ifnet *);
void in_purgeaddr(struct ifaddr *);
int in_addhost(struct in_ifaddr *, struct sockaddr_in *);
int in_scrubhost(struct in_ifaddr *, struct sockaddr_in *);
int in_insert_prefix(struct in_ifaddr *);
void in_remove_prefix(struct in_ifaddr *);

/*
 * Determine whether an IP address is in a reserved set of addresses
 * that may not be forwarded, or whether datagrams to that destination
 * may be forwarded.
 */
int
in_canforward(struct in_addr in)
{
        u_int32_t net;

        if (IN_MULTICAST(in.s_addr))
                return (0);
        if (IN_CLASSA(in.s_addr)) {
                net = in.s_addr & IN_CLASSA_NET;
                if (net == 0 ||
                    net == htonl(IN_LOOPBACKNET << IN_CLASSA_NSHIFT))
                        return (0);
        }
        return (1);
}

/*
 * Trim a mask in a sockaddr
 */
void
in_socktrim(struct sockaddr_in *ap)
{
        char *cplim = (char *) &ap->sin_addr;
        char *cp = (char *) (&ap->sin_addr + 1);

        ap->sin_len = 0;
        while (--cp >= cplim)
                if (*cp) {
                        (ap)->sin_len = cp - (char *) (ap) + 1;
                        break;
                }
}

int
in_mask2len(struct in_addr *mask)
{
        int x, y;
        u_char *p;

        p = (u_char *)mask;
        for (x = 0; x < sizeof(*mask); x++) {
                if (p[x] != 0xff)
                        break;
        }
        y = 0;
        if (x < sizeof(*mask)) {
                for (y = 0; y < 8; y++) {
                        if ((p[x] & (0x80 >> y)) == 0)
                                break;
                }
        }
        return x * 8 + y;
}

void
in_len2mask(struct in_addr *mask, int len)
{
        int i;
        u_char *p;

        p = (u_char *)mask;
        bzero(mask, sizeof(*mask));
        for (i = 0; i < len / 8; i++)
                p[i] = 0xff;
        if (len % 8)
                p[i] = (0xff00 >> (len % 8)) & 0xff;
}

int
in_nam2sin(const struct mbuf *nam, struct sockaddr_in **sin)
{
        struct sockaddr *sa = mtod(nam, struct sockaddr *);

        if (nam->m_len < offsetof(struct sockaddr, sa_data))
                return EINVAL;
        if (sa->sa_family != AF_INET)
                return EAFNOSUPPORT;
        if (sa->sa_len != nam->m_len)
                return EINVAL;
        if (sa->sa_len != sizeof(struct sockaddr_in))
                return EINVAL;
        *sin = satosin(sa);

        return 0;
}

int
in_sa2sin(struct sockaddr *sa, struct sockaddr_in **sin)
{
        if (sa->sa_family != AF_INET)
                return EAFNOSUPPORT;
        if (sa->sa_len != sizeof(struct sockaddr_in))
                return EINVAL;
        *sin = satosin(sa);

        return 0;
}

/*
 * Find the internet address structure (in_ifaddr) corresponding
 * to a given interface (ifnet structure).
 */
struct in_ifaddr *
in_ifp2ia(struct ifnet *ifp)
{
        struct in_ifaddr *ia = NULL;
        struct ifaddr *ifa;

        NET_ASSERT_LOCKED();

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                ia = ifatoia(ifa);
                break;
        }

        return (ia);
}

int
in_control(struct socket *so, u_long cmd, caddr_t data, struct ifnet *ifp)
{
        int privileged;

        privileged = 0;
        if ((so->so_state & SS_PRIV) != 0)
                privileged++;

        switch (cmd) {
#ifdef MROUTING
        case SIOCGETVIFCNT:
        case SIOCGETSGCNT:
                return mrt_ioctl(so, cmd, data);
#endif /* MROUTING */
        default:
                return in_ioctl(cmd, data, ifp, privileged);
        }
}

int
in_ioctl(u_long cmd, caddr_t data, struct ifnet *ifp, int privileged)
{
        struct ifreq *ifr = (struct ifreq *)data;
        struct ifaddr *ifa;
        struct in_ifaddr *ia = NULL;
        struct sockaddr_in *sin = NULL, oldaddr;
        int error = 0;

        if (ifp == NULL)
                return (ENXIO);

        switch (cmd) {
        case SIOCGIFADDR:
        case SIOCGIFNETMASK:
        case SIOCGIFDSTADDR:
        case SIOCGIFBRDADDR:
                return in_ioctl_get(cmd, data, ifp);
        case SIOCSIFADDR:
                if (!privileged)
                        return (EPERM);
                return in_ioctl_set_ifaddr(cmd, data, ifp);
        case SIOCAIFADDR:
        case SIOCDIFADDR:
                if (!privileged)
                        return (EPERM);
                return in_ioctl_change_ifaddr(cmd, data, ifp);
        case SIOCSIFNETMASK:
        case SIOCSIFDSTADDR:
        case SIOCSIFBRDADDR:
                break;
        default:
                return (EOPNOTSUPP);
        }

        if (!privileged)
                return (EPERM);

        if (ifr->ifr_addr.sa_family == AF_INET) {
                error = in_sa2sin(&ifr->ifr_addr, &sin);
                if (error)
                        return (error);
        }

        NET_LOCK();
        KERNEL_LOCK();

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                /* find first address or exact match */
                if (ia == NULL)
                        ia = ifatoia(ifa);
                if (sin == NULL || sin->sin_addr.s_addr == INADDR_ANY)
                        break;
                if (ifatoia(ifa)->ia_addr.sin_addr.s_addr ==
                    sin->sin_addr.s_addr) {
                        ia = ifatoia(ifa);
                        break;
                }
        }
        if (ia == NULL) {
                error = EADDRNOTAVAIL;
                goto err;
        }

        switch (cmd) {
        case SIOCSIFDSTADDR:
                if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
                        error = EINVAL;
                        break;
                }
                error = in_sa2sin(&ifr->ifr_dstaddr, &sin);
                if (error)
                        break;
                oldaddr = ia->ia_dstaddr;
                ia->ia_dstaddr = *sin;
                error = (*ifp->if_ioctl)(ifp, SIOCSIFDSTADDR, (caddr_t)ia);
                if (error) {
                        ia->ia_dstaddr = oldaddr;
                        break;
                }
                in_scrubhost(ia, &oldaddr);
                in_addhost(ia, &ia->ia_dstaddr);
                break;

        case SIOCSIFBRDADDR:
                if ((ifp->if_flags & IFF_BROADCAST) == 0) {
                        error = EINVAL;
                        break;
                }
                error = in_sa2sin(&ifr->ifr_broadaddr, &sin);
                if (error)
                        break;
                ifa_update_broadaddr(ifp, &ia->ia_ifa, sintosa(sin));
                break;

        case SIOCSIFNETMASK:
                if (ifr->ifr_addr.sa_len < 8) {
                        error = EINVAL;
                        break;
                }
                /* do not check inet family or strict len */
                sin = satosin(&ifr->ifr_addr);
                if (ntohl(sin->sin_addr.s_addr) &
                    (~ntohl(sin->sin_addr.s_addr) >> 1)) {
                        /* non-contiguous netmask */
                        error = EINVAL;
                        break;
                }
                ia->ia_netmask = ia->ia_sockmask.sin_addr.s_addr =
                    sin->sin_addr.s_addr;
                break;
        }
err:
        KERNEL_UNLOCK();
        NET_UNLOCK();
        return (error);
}

int
in_ioctl_set_ifaddr(u_long cmd, caddr_t data, struct ifnet *ifp)
{
        struct ifreq *ifr = (struct ifreq *)data;
        struct ifaddr *ifa;
        struct in_ifaddr *ia = NULL;
        struct sockaddr_in *sin;
        int error = 0;
        int newifaddr;

        if (cmd != SIOCSIFADDR)
                panic("%s: invalid ioctl %lu", __func__, cmd);

        error = in_sa2sin(&ifr->ifr_addr, &sin);
        if (error)
                return (error);

        NET_LOCK();
        KERNEL_LOCK();

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                /* find first address */
                ia = ifatoia(ifa);
                break;
        }
        if (ia == NULL) {
                ia = malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
                refcnt_init_trace(&ia->ia_ifa.ifa_refcnt, DT_REFCNT_IDX_IFADDR);
                ia->ia_addr.sin_family = AF_INET;
                ia->ia_addr.sin_len = sizeof(ia->ia_addr);
                ia->ia_ifa.ifa_addr = sintosa(&ia->ia_addr);
                ia->ia_ifa.ifa_dstaddr = sintosa(&ia->ia_dstaddr);
                ia->ia_ifa.ifa_netmask = sintosa(&ia->ia_sockmask);
                ia->ia_sockmask.sin_len = 8;
                if (ifp->if_flags & IFF_BROADCAST) {
                        ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
                        ia->ia_broadaddr.sin_family = AF_INET;
                }
                ia->ia_ifp = ifp;

                newifaddr = 1;
        } else
                newifaddr = 0;

        in_ifscrub(ifp, ia);
        error = in_ifinit(ifp, ia, sin, newifaddr);
        if (!error)
                if_addrhooks_run(ifp);

        KERNEL_UNLOCK();
        NET_UNLOCK();
        return error;
}

int
in_ioctl_change_ifaddr(u_long cmd, caddr_t data, struct ifnet *ifp)
{
        struct ifaddr *ifa;
        struct in_ifaddr *ia = NULL;
        struct in_aliasreq *ifra = (struct in_aliasreq *)data;
        struct sockaddr_in *sin = NULL, *dstsin = NULL, *broadsin = NULL;
        struct sockaddr_in *masksin = NULL;
        int error = 0;
        int newifaddr;

        if (ifra->ifra_addr.sin_family == AF_INET) {
                error = in_sa2sin(sintosa(&ifra->ifra_addr), &sin);
                if (error)
                        return (error);
        }

        NET_LOCK();
        KERNEL_LOCK();

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                /* find first address, if no exact match wanted */
                if (sin == NULL || sin->sin_addr.s_addr ==
                    ifatoia(ifa)->ia_addr.sin_addr.s_addr) {
                        ia = ifatoia(ifa);
                        break;
                }
        }

        switch (cmd) {
        case SIOCAIFADDR: {
                int needinit = 0;

                if (ifra->ifra_mask.sin_len) {
                        if (ifra->ifra_mask.sin_len < 8) {
                                error = EINVAL;
                                break;
                        }
                        /* do not check inet family or strict len */
                        masksin = &ifra->ifra_mask;
                        if (ntohl(masksin->sin_addr.s_addr) &
                            (~ntohl(masksin->sin_addr.s_addr) >> 1)) {
                                /* non-contiguous netmask */
                                error = EINVAL;
                                break;
                        }
                }
                if ((ifp->if_flags & IFF_POINTOPOINT) &&
                    ifra->ifra_dstaddr.sin_family == AF_INET) {
                        error = in_sa2sin(sintosa(&ifra->ifra_dstaddr),
                            &dstsin);
                        if (error)
                                break;
                }
                if ((ifp->if_flags & IFF_BROADCAST) &&
                    ifra->ifra_broadaddr.sin_family == AF_INET) {
                        error = in_sa2sin(sintosa(&ifra->ifra_broadaddr),
                            &broadsin);
                        if (error)
                                break;
                }

                if (ia == NULL) {
                        ia = malloc(sizeof *ia, M_IFADDR, M_WAITOK | M_ZERO);
                        refcnt_init_trace(&ia->ia_ifa.ifa_refcnt,
                            DT_REFCNT_IDX_IFADDR);
                        ia->ia_addr.sin_family = AF_INET;
                        ia->ia_addr.sin_len = sizeof(ia->ia_addr);
                        ia->ia_ifa.ifa_addr = sintosa(&ia->ia_addr);
                        ia->ia_ifa.ifa_dstaddr = sintosa(&ia->ia_dstaddr);
                        ia->ia_ifa.ifa_netmask = sintosa(&ia->ia_sockmask);
                        ia->ia_sockmask.sin_len = 8;
                        if (ifp->if_flags & IFF_BROADCAST) {
                                ia->ia_broadaddr.sin_len = sizeof(ia->ia_addr);
                                ia->ia_broadaddr.sin_family = AF_INET;
                        }
                        ia->ia_ifp = ifp;

                        newifaddr = 1;
                } else
                        newifaddr = 0;

                if (sin == NULL) {
                        sin = &ia->ia_addr;
                } else if (newifaddr ||
                    sin->sin_addr.s_addr != ia->ia_addr.sin_addr.s_addr) {
                        needinit = 1;
                }
                if (masksin != NULL) {
                        in_ifscrub(ifp, ia);
                        ia->ia_netmask = ia->ia_sockmask.sin_addr.s_addr =
                            masksin->sin_addr.s_addr;
                        needinit = 1;
                }
                if (dstsin != NULL) {
                        in_ifscrub(ifp, ia);
                        ia->ia_dstaddr = *dstsin;
                        needinit = 1;
                }
                if (broadsin != NULL) {
                        if (newifaddr)
                                ia->ia_broadaddr = *broadsin;
                        else
                                ifa_update_broadaddr(ifp, &ia->ia_ifa,
                                    sintosa(broadsin));
                }
                if (needinit) {
                        error = in_ifinit(ifp, ia, sin, newifaddr);
                        if (error)
                                break;
                }
                if_addrhooks_run(ifp);
                break;
            }
        case SIOCDIFADDR:
                if (ia == NULL) {
                        error = EADDRNOTAVAIL;
                        break;
                }
                /*
                 * Even if the individual steps were safe, shouldn't
                 * these kinds of changes happen atomically?  What
                 * should happen to a packet that was routed after
                 * the scrub but before the other steps?
                 */
                in_purgeaddr(&ia->ia_ifa);
                if_addrhooks_run(ifp);
                break;

        default:
                panic("%s: invalid ioctl %lu", __func__, cmd);
        }

        KERNEL_UNLOCK();
        NET_UNLOCK();
        return (error);
}

int
in_ioctl_get(u_long cmd, caddr_t data, struct ifnet *ifp)
{
        struct ifreq *ifr = (struct ifreq *)data;
        struct ifaddr *ifa;
        struct in_ifaddr *ia = NULL;
        struct sockaddr *sa;
        struct sockaddr_in *sin = NULL;
        int error = 0;

        sa = &ifr->ifr_addr;
        if (sa->sa_family == AF_INET) {
                sa->sa_len = sizeof(struct sockaddr_in);
                error = in_sa2sin(sa, &sin);
                if (error)
                        return (error);
        }

        NET_LOCK_SHARED();

        TAILQ_FOREACH(ifa, &ifp->if_addrlist, ifa_list) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                /* find first address or exact match */
                if (ia == NULL)
                        ia = ifatoia(ifa);
                if (sin == NULL || sin->sin_addr.s_addr == INADDR_ANY)
                        break;
                if (ifatoia(ifa)->ia_addr.sin_addr.s_addr ==
                    sin->sin_addr.s_addr) {
                        ia = ifatoia(ifa);
                        break;
                }
        }
        if (ia == NULL) {
                error = EADDRNOTAVAIL;
                goto err;
        }

        switch(cmd) {
        case SIOCGIFADDR:
                *satosin(&ifr->ifr_addr) = ia->ia_addr;
                break;

        case SIOCGIFBRDADDR:
                if ((ifp->if_flags & IFF_BROADCAST) == 0) {
                        error = EINVAL;
                        break;
                }
                *satosin(&ifr->ifr_dstaddr) = ia->ia_broadaddr;
                break;

        case SIOCGIFDSTADDR:
                if ((ifp->if_flags & IFF_POINTOPOINT) == 0) {
                        error = EINVAL;
                        break;
                }
                *satosin(&ifr->ifr_dstaddr) = ia->ia_dstaddr;
                break;

        case SIOCGIFNETMASK:
                *satosin(&ifr->ifr_addr) = ia->ia_sockmask;
                break;

        default:
                panic("%s: invalid ioctl %lu", __func__, cmd);
        }

err:
        NET_UNLOCK_SHARED();
        return (error);
}

/*
 * Delete any existing route for an interface.
 */
void
in_ifscrub(struct ifnet *ifp, struct in_ifaddr *ia)
{
        if (ISSET(ifp->if_flags, IFF_POINTOPOINT))
                in_scrubhost(ia, &ia->ia_dstaddr);
        else if (!ISSET(ifp->if_flags, IFF_LOOPBACK))
                in_remove_prefix(ia);
}

/*
 * Initialize an interface's internet address
 * and routing table entry.
 */
int
in_ifinit(struct ifnet *ifp, struct in_ifaddr *ia, struct sockaddr_in *sin,
    int newaddr)
{
        u_int32_t i = sin->sin_addr.s_addr;
        struct sockaddr_in oldaddr;
        int error = 0, rterror;

        NET_ASSERT_LOCKED();

        /*
         * Always remove the address from the tree to make sure its
         * position gets updated in case the key changes.
         */
        if (!newaddr) {
                rt_ifa_dellocal(&ia->ia_ifa);
                ifa_del(ifp, &ia->ia_ifa);
        }
        oldaddr = ia->ia_addr;
        ia->ia_addr = *sin;

        if (ia->ia_netmask == 0) {
                if (IN_CLASSA(i))
                        ia->ia_netmask = IN_CLASSA_NET;
                else if (IN_CLASSB(i))
                        ia->ia_netmask = IN_CLASSB_NET;
                else
                        ia->ia_netmask = IN_CLASSC_NET;
                ia->ia_sockmask.sin_addr.s_addr = ia->ia_netmask;
        }

        /*
         * Give the interface a chance to initialize
         * if this is its first address,
         * and to validate the address if necessary.
         */
        if ((error = (*ifp->if_ioctl)(ifp, SIOCSIFADDR, (caddr_t)ia))) {
                ia->ia_addr = oldaddr;
        }

        /*
         * Add the address to the local list and the global tree.  If an
         * error occurred, put back the original address.
         */
        ifa_add(ifp, &ia->ia_ifa);
        rterror = rt_ifa_addlocal(&ia->ia_ifa);

        if (rterror) {
                if (!newaddr)
                        ifa_del(ifp, &ia->ia_ifa);
                if (!error)
                        error = rterror;
                goto out;
        }
        if (error)
                goto out;


        ia->ia_net = i & ia->ia_netmask;
        in_socktrim(&ia->ia_sockmask);
        /*
         * Add route for the network.
         */
        ia->ia_ifa.ifa_metric = ifp->if_metric;
        if (ISSET(ifp->if_flags, IFF_BROADCAST)) {
                if (IN_RFC3021_SUBNET(ia->ia_netmask))
                        ia->ia_broadaddr.sin_addr.s_addr = 0;
                else {
                        ia->ia_broadaddr.sin_addr.s_addr =
                            ia->ia_net | ~ia->ia_netmask;
                }
        }

        if (ISSET(ifp->if_flags, IFF_POINTOPOINT)) {
                /* XXX We should not even call in_ifinit() in this case. */
                if (ia->ia_dstaddr.sin_family != AF_INET)
                        goto out;
                error = in_addhost(ia, &ia->ia_dstaddr);
        } else if (!ISSET(ifp->if_flags, IFF_LOOPBACK)) {
                error = in_insert_prefix(ia);
        }

        /*
         * If the interface supports multicast, join the "all hosts"
         * multicast group on that interface.
         */
        if ((ifp->if_flags & IFF_MULTICAST) && ia->ia_allhosts == NULL) {
                struct in_addr addr;

                addr.s_addr = INADDR_ALLHOSTS_GROUP;
                ia->ia_allhosts = in_addmulti(&addr, ifp);
        }

out:
        if (error && newaddr)
                in_purgeaddr(&ia->ia_ifa);

        return (error);
}

void
in_purgeaddr(struct ifaddr *ifa)
{
        struct ifnet *ifp = ifa->ifa_ifp;
        struct in_ifaddr *ia = ifatoia(ifa);

        NET_ASSERT_LOCKED();

        in_ifscrub(ifp, ia);

        rt_ifa_dellocal(&ia->ia_ifa);
        rt_ifa_purge(&ia->ia_ifa);
        ifa_del(ifp, &ia->ia_ifa);

        if (ia->ia_allhosts != NULL) {
                in_delmulti(ia->ia_allhosts);
                ia->ia_allhosts = NULL;
        }

        ia->ia_ifp = NULL;
        ifafree(&ia->ia_ifa);
}

int
in_addhost(struct in_ifaddr *ia, struct sockaddr_in *dst)
{
        return rt_ifa_add(&ia->ia_ifa, RTF_HOST | RTF_MPATH,
            sintosa(dst), ia->ia_ifa.ifa_ifp->if_rdomain);
}

int
in_scrubhost(struct in_ifaddr *ia, struct sockaddr_in *dst)
{
        return rt_ifa_del(&ia->ia_ifa, RTF_HOST,
            sintosa(dst), ia->ia_ifa.ifa_ifp->if_rdomain);
}

/*
 * Insert the cloning and broadcast routes for this subnet.
 */
int
in_insert_prefix(struct in_ifaddr *ia)
{
        struct ifaddr *ifa = &ia->ia_ifa;
        int error;

        error = rt_ifa_add(ifa, RTF_CLONING | RTF_CONNECTED | RTF_MPATH,
            ifa->ifa_addr, ifa->ifa_ifp->if_rdomain);
        if (error)
                return (error);

        if (ia->ia_broadaddr.sin_addr.s_addr != 0) {
                error = rt_ifa_add(ifa, RTF_HOST | RTF_BROADCAST | RTF_MPATH,
                    ifa->ifa_broadaddr, ifa->ifa_ifp->if_rdomain);
        }

        return (error);
}

void
in_remove_prefix(struct in_ifaddr *ia)
{
        struct ifaddr *ifa = &ia->ia_ifa;

        rt_ifa_del(ifa, RTF_CLONING | RTF_CONNECTED,
            ifa->ifa_addr, ifa->ifa_ifp->if_rdomain);

        if (ia->ia_broadaddr.sin_addr.s_addr != 0) {
                rt_ifa_del(ifa, RTF_HOST | RTF_BROADCAST,
                    ifa->ifa_broadaddr, ifa->ifa_ifp->if_rdomain);
        }
}

/*
 * Return 1 if the address is a local broadcast address.
 */
int
in_broadcast(struct in_addr in, u_int rtableid)
{
        struct ifnet *ifn;
        struct ifaddr *ifa;
        u_int rdomain;

        NET_ASSERT_LOCKED();

        rdomain = rtable_l2(rtableid);

#define ia (ifatoia(ifa))
        TAILQ_FOREACH(ifn, &ifnetlist, if_list) {
                if (ifn->if_rdomain != rdomain)
                        continue;
                if ((ifn->if_flags & IFF_BROADCAST) == 0)
                        continue;
                TAILQ_FOREACH(ifa, &ifn->if_addrlist, ifa_list)
                        if (ifa->ifa_addr->sa_family == AF_INET &&
                            in.s_addr != ia->ia_addr.sin_addr.s_addr &&
                            in.s_addr == ia->ia_broadaddr.sin_addr.s_addr)
                                return 1;
        }
        return (0);
#undef ia
}

/*
 * Look up the in_multi record for a given IP multicast address
 * on a given interface.  Return the matching record if found or NULL.
 */
struct in_multi *
in_lookupmulti(const struct in_addr *addr, struct ifnet *ifp)
{
        struct in_multi *inm = NULL;
        struct ifmaddr *ifma;

        rw_assert_anylock(&ifp->if_maddrlock);

        TAILQ_FOREACH(ifma, &ifp->if_maddrlist, ifma_list) {
                if (ifma->ifma_addr->sa_family == AF_INET &&
                    ifmatoinm(ifma)->inm_addr.s_addr == addr->s_addr) {
                        inm = ifmatoinm(ifma);
                        break;
                }
        }
        return (inm);
}

/*
 * Add an address to the list of IP multicast addresses for a given interface.
 */
struct in_multi *
in_addmulti(const struct in_addr *addr, struct ifnet *ifp)
{
        struct in_multi *inm, *new_inm = NULL;
        struct igmp_pktinfo pkt;
        struct ifreq ifr;

        /*
         * See if address already in list.
         */
        rw_enter_write(&ifp->if_maddrlock);
        inm = in_lookupmulti(addr, ifp);
        if (inm != NULL)
                goto found;
        rw_exit_write(&ifp->if_maddrlock);

        /*
         * New address; allocate a new multicast record
         * and link it into the interface's multicast list.
         */
        new_inm = malloc(sizeof(*inm), M_IPMADDR, M_WAITOK | M_ZERO);

        /*
         * Ask the network driver to update its multicast reception
         * filter appropriately for the new address.
         */
        memset(&ifr, 0, sizeof(ifr));
        satosin(&ifr.ifr_addr)->sin_len = sizeof(struct sockaddr_in);
        satosin(&ifr.ifr_addr)->sin_family = AF_INET;
        satosin(&ifr.ifr_addr)->sin_addr = *addr;
        KERNEL_LOCK();
        if ((*ifp->if_ioctl)(ifp, SIOCADDMULTI,(caddr_t)&ifr) != 0) {
                KERNEL_UNLOCK();
                goto out;
        }
        KERNEL_UNLOCK();

        rw_enter_write(&ifp->if_maddrlock);
        /* check again after unlock and lock */
        inm = in_lookupmulti(addr, ifp);
        if (inm != NULL)
                goto found;
        inm = new_inm;
        inm->inm_sin.sin_len = sizeof(struct sockaddr_in);
        inm->inm_sin.sin_family = AF_INET;
        inm->inm_sin.sin_addr = *addr;
        refcnt_init_trace(&inm->inm_refcnt, DT_REFCNT_IDX_IFMADDR);
        inm->inm_ifidx = ifp->if_index;
        inm->inm_ifma.ifma_addr = sintosa(&inm->inm_sin);

        /*
         * Let IGMP know that we have joined a new IP multicast group.
         */
        TAILQ_INSERT_HEAD(&ifp->if_maddrlist, &inm->inm_ifma, ifma_list);
        pkt.ipi_ifidx = 0;
        igmp_joingroup(inm, ifp, &pkt);
        rw_exit_write(&ifp->if_maddrlock);

        if (pkt.ipi_ifidx)
                igmp_sendpkt(&pkt);
        return (inm);

 found:
        refcnt_take(&inm->inm_refcnt);
        rw_exit_write(&ifp->if_maddrlock);
 out:
        free(new_inm, M_IPMADDR, sizeof(*inm));
        return (inm);
}

/*
 * Delete a multicast address record.
 */
void
in_delmulti(struct in_multi *inm)
{
        struct igmp_pktinfo pkt;
        struct ifreq ifr;
        struct ifnet *ifp;

        if (refcnt_rele(&inm->inm_refcnt) == 0)
                return;

        ifp = if_get(inm->inm_ifidx);
        if (ifp != NULL) {
                rw_enter_write(&ifp->if_maddrlock);
                /*
                 * No remaining claims to this record; let IGMP know that
                 * we are leaving the multicast group.
                 */
                pkt.ipi_ifidx = 0;
                igmp_leavegroup(inm, ifp, &pkt);
                TAILQ_REMOVE(&ifp->if_maddrlist, &inm->inm_ifma, ifma_list);
                rw_exit_write(&ifp->if_maddrlock);

                if (pkt.ipi_ifidx)
                        igmp_sendpkt(&pkt);

                /*
                 * Notify the network driver to update its multicast
                 * reception filter.
                 */
                memset(&ifr, 0, sizeof(ifr));
                satosin(&ifr.ifr_addr)->sin_len = sizeof(struct sockaddr_in);
                satosin(&ifr.ifr_addr)->sin_family = AF_INET;
                satosin(&ifr.ifr_addr)->sin_addr = inm->inm_addr;
                KERNEL_LOCK();
                (*ifp->if_ioctl)(ifp, SIOCDELMULTI, (caddr_t)&ifr);
                KERNEL_UNLOCK();

                if_put(ifp);
        }

        free(inm, M_IPMADDR, sizeof(*inm));
}

/*
 * Return 1 if the multicast group represented by ``addr'' has been
 * joined by interface ``ifp'', 0 otherwise.
 */
int
in_hasmulti(const struct in_addr *addr, struct ifnet *ifp)
{
        struct in_multi *inm;
        int joined;

        rw_enter_read(&ifp->if_maddrlock);
        inm = in_lookupmulti(addr, ifp);
        joined = (inm != NULL);
        rw_exit_read(&ifp->if_maddrlock);

        return (joined);
}

void
in_ifdetach(struct ifnet *ifp)
{
        struct ifaddr *ifa, *next;

        /* nuke any of IPv4 addresses we have */
        TAILQ_FOREACH_SAFE(ifa, &ifp->if_addrlist, ifa_list, next) {
                if (ifa->ifa_addr->sa_family != AF_INET)
                        continue;
                in_purgeaddr(ifa);
                if_addrhooks_run(ifp);
        }

        if (ifp->if_xflags & IFXF_AUTOCONF4)
                ifp->if_xflags &= ~IFXF_AUTOCONF4;
}

void
in_prefixlen2mask(struct in_addr *maskp, int plen)
{
        if (plen == 0)
                maskp->s_addr = 0;
        else
                maskp->s_addr = htonl(0xffffffff << (32 - plen));
}