/*      $NetBSD: at_control.c,v 1.44 2023/03/30 15:58:10 riastradh Exp $         */

/*
 * Copyright (c) 1990,1994 Regents of The University of Michigan.
 * All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software and
 * its documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appears in all copies and
 * that both that copyright notice and this permission notice appear
 * in supporting documentation, and that the name of The University
 * of Michigan not be used in advertising or publicity pertaining to
 * distribution of the software without specific, written prior
 * permission. This software is supplied as is without expressed or
 * implied warranties of any kind.
 *
 * This product includes software developed by the University of
 * California, Berkeley and its contributors.
 *
 *      Research Systems Unix Group
 *      The University of Michigan
 *      c/o Wesley Craig
 *      535 W. William Street
 *      Ann Arbor, Michigan
 *      +1-313-764-2278
 *      netatalk@umich.edu
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: at_control.c,v 1.44 2023/03/30 15:58:10 riastradh Exp $");

#include "opt_atalk.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/errno.h>
#include <sys/ioctl.h>
#include <sys/mbuf.h>
#include <sys/kernel.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/kauth.h>
#include <net/if.h>
#include <net/route.h>
#include <net/if_ether.h>
#include <netinet/in.h>
#undef s_net

#include <netatalk/at.h>
#include <netatalk/at_var.h>
#include <netatalk/aarp.h>
#include <netatalk/phase2.h>
#include <netatalk/at_extern.h>

static int aa_dorangeroute(struct ifaddr * ifa,
    u_int first, u_int last, int cmd);
static int aa_addsingleroute(struct ifaddr * ifa,
    struct at_addr * addr, struct at_addr * mask);
static int aa_delsingleroute(struct ifaddr * ifa,
    struct at_addr * addr, struct at_addr * mask);
static int aa_dosingleroute(struct ifaddr * ifa, struct at_addr * addr,
    struct at_addr * mask, int cmd, int flags);
static int at_scrub(struct ifnet * ifp, struct at_ifaddr * aa);
static int at_ifinit(struct ifnet *, struct at_ifaddr *,
    const struct sockaddr_at *);
#if 0
static void aa_clean(void);
#endif

#define sateqaddr(a,b)  ((a)->sat_len == (b)->sat_len && \
                         (a)->sat_family == (b)->sat_family && \
                         (a)->sat_addr.s_net == (b)->sat_addr.s_net && \
                         (a)->sat_addr.s_node == (b)->sat_addr.s_node )

int
at_control(u_long cmd, void *data, struct ifnet *ifp)
{
        struct ifreq   *ifr = (struct ifreq *) data;
        const struct sockaddr_at *csat;
        struct netrange *nr;
        const struct netrange *cnr;
        struct at_aliasreq *ifra = (struct at_aliasreq *) data;
        struct at_ifaddr *aa0;
        struct at_ifaddr *aa = 0;

        /*
         * If we have an ifp, then find the matching at_ifaddr if it exists
         */
        if (ifp)
                TAILQ_FOREACH(aa, &at_ifaddr, aa_list)
                        if (aa->aa_ifp == ifp)
                                break;

        /*
         * In this first switch table we are basically getting ready for
         * the second one, by getting the atalk-specific things set up
         * so that they start to look more similar to other protocols etc.
         */

        switch (cmd) {
        case SIOCAIFADDR:
        case SIOCDIFADDR:
                /*
                 * If we have an appletalk sockaddr, scan forward of where
                 * we are now on the at_ifaddr list to find one with a matching
                 * address on this interface.
                 * This may leave aa pointing to the first address on the
                 * NEXT interface!
                 */
                if (ifra->ifra_addr.sat_family == AF_APPLETALK) {
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list))
                                if (aa->aa_ifp == ifp &&
                                    sateqaddr(&aa->aa_addr, &ifra->ifra_addr))
                                        break;
                }
                /*
                 * If we a retrying to delete an address but didn't find such,
                 * then return with an error
                 */
                if (cmd == SIOCDIFADDR && aa == 0)
                        return (EADDRNOTAVAIL);
                /* FALLTHROUGH */

        case SIOCSIFADDR:
                /*
                 * If we are not superuser, then we don't get to do these
                 * ops.
                 */
                if (kauth_authorize_network(kauth_cred_get(),
                    KAUTH_NETWORK_INTERFACE,
                    KAUTH_REQ_NETWORK_INTERFACE_SETPRIV, ifp, (void *)cmd,
                    NULL) != 0)
                        return (EPERM);

                csat = satocsat(ifreq_getaddr(cmd, ifr));
                cnr = (const struct netrange *)csat->sat_zero;
                if (cnr->nr_phase == 1) {
                        /*
                         * Look for a phase 1 address on this interface.
                         * This may leave aa pointing to the first address on
                         * the NEXT interface!
                         */
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list)) {
                                if (aa->aa_ifp == ifp &&
                                    (aa->aa_flags & AFA_PHASE2) == 0)
                                        break;
                        }
                } else {        /* default to phase 2 */
                        /*
                         * Look for a phase 2 address on this interface.
                         * This may leave aa pointing to the first address on
                         * the NEXT interface!
                         */
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list)) {
                                if (aa->aa_ifp == ifp &&
                                    (aa->aa_flags & AFA_PHASE2))
                                        break;
                        }
                }

                if (ifp == 0)
                        panic("at_control");

                /*
                 * If we failed to find an existing at_ifaddr entry, then we
                 * allocate a fresh one.
                 * XXX change this to use malloc
                 */
                if (aa == (struct at_ifaddr *) 0) {
                        aa = (struct at_ifaddr *)
                            malloc(sizeof(struct at_ifaddr), M_IFADDR,
                            M_WAITOK|M_ZERO);

                        if (aa == NULL)
                                return (ENOBUFS);

                        callout_init(&aa->aa_probe_ch, 0);

                        if ((aa0 = TAILQ_FIRST(&at_ifaddr)) != NULL) {
                                /*
                                 * Don't let the loopback be first, since the
                                 * first address is the machine's default
                                 * address for binding.
                                 * If it is, stick ourself in front, otherwise
                                 * go to the back of the list.
                                 */
                                if (aa0->aa_ifp->if_flags & IFF_LOOPBACK) {
                                        TAILQ_INSERT_HEAD(&at_ifaddr, aa,
                                            aa_list);
                                } else {
                                        TAILQ_INSERT_TAIL(&at_ifaddr, aa,
                                            aa_list);
                                }
                        } else {
                                TAILQ_INSERT_TAIL(&at_ifaddr, aa, aa_list);
                        }
                        ifaref(&aa->aa_ifa);
                        ifa_psref_init(&aa->aa_ifa);

                        /*
                         * Find the end of the interface's addresses
                         * and link our new one on the end
                         */
                        ifa_insert(ifp, &aa->aa_ifa);

                        /*
                         * As the at_ifaddr contains the actual sockaddrs,
                         * and the ifaddr itself, link them al together
                         * correctly.
                         */
                        aa->aa_ifa.ifa_addr =
                            (struct sockaddr *) &aa->aa_addr;
                        aa->aa_ifa.ifa_dstaddr =
                            (struct sockaddr *) &aa->aa_addr;
                        aa->aa_ifa.ifa_netmask =
                            (struct sockaddr *) &aa->aa_netmask;

                        /*
                         * Set/clear the phase 2 bit.
                         */
                        if (cnr->nr_phase == 1)
                                aa->aa_flags &= ~AFA_PHASE2;
                        else
                                aa->aa_flags |= AFA_PHASE2;

                        /*
                         * and link it all together
                         */
                        aa->aa_ifp = ifp;
                } else {
                        /*
                         * If we DID find one then we clobber any routes
                         * dependent on it..
                         */
                        at_scrub(ifp, aa);
                }
                break;

        case SIOCGIFADDR:
                csat = satocsat(ifreq_getaddr(cmd, ifr));
                cnr = (const struct netrange *)csat->sat_zero;
                if (cnr->nr_phase == 1) {
                        /*
                         * If the request is specifying phase 1, then
                         * only look at a phase one address
                         */
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list)) {
                                if (aa->aa_ifp == ifp &&
                                    (aa->aa_flags & AFA_PHASE2) == 0)
                                        break;
                        }
                } else if (cnr->nr_phase == 2) {
                        /*
                         * If the request is specifying phase 2, then
                         * only look at a phase two address
                         */
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list)) {
                                if (aa->aa_ifp == ifp &&
                                    (aa->aa_flags & AFA_PHASE2))
                                        break;
                        }
                } else {
                        /*
                         * default to everything
                         */
                        for (; aa; aa = TAILQ_NEXT(aa, aa_list)) {
                                if (aa->aa_ifp == ifp)
                                        break;
                        }
                }

                if (aa == (struct at_ifaddr *) 0)
                        return (EADDRNOTAVAIL);
                break;
        }

        /*
         * By the time this switch is run we should be able to assume that
         * the "aa" pointer is valid when needed.
         */
        switch (cmd) {
        case SIOCGIFADDR: {
                union {
                        struct sockaddr sa;
                        struct sockaddr_at sat;
                } u;

                /*
                 * copy the contents of the sockaddr blindly.
                 */
                sockaddr_copy(&u.sa, sizeof(u),
                    (const struct sockaddr *)&aa->aa_addr);
                /*
                 * and do some cleanups
                 */
                nr = (struct netrange *)&u.sat.sat_zero;
                nr->nr_phase = (aa->aa_flags & AFA_PHASE2) ? 2 : 1;
                nr->nr_firstnet = aa->aa_firstnet;
                nr->nr_lastnet = aa->aa_lastnet;
                ifreq_setaddr(cmd, ifr, &u.sa);
                break;
        }

        case SIOCSIFADDR:
                return at_ifinit(ifp, aa,
                    (const struct sockaddr_at *)ifreq_getaddr(cmd, ifr));

        case SIOCAIFADDR:
                if (sateqaddr(&ifra->ifra_addr, &aa->aa_addr))
                        return 0;
                return at_ifinit(ifp, aa,
                    (const struct sockaddr_at *)ifreq_getaddr(cmd, ifr));

        case SIOCDIFADDR:
                at_purgeaddr(&aa->aa_ifa);
                break;

        default:
                return ENOTTY;
        }
        return (0);
}

void
at_purgeaddr(struct ifaddr *ifa)
{
        struct ifnet *ifp = ifa->ifa_ifp;
        struct at_ifaddr *aa = (void *) ifa;

        /*
         * scrub all routes.. didn't we just DO this? XXX yes, del it
         * XXX above XXX not necessarily true anymore
         */
        at_scrub(ifp, aa);

        /*
         * remove the ifaddr from the interface
         */
        ifa_remove(ifp, &aa->aa_ifa);
        TAILQ_REMOVE(&at_ifaddr, aa, aa_list);
        ifafree(&aa->aa_ifa);
}

void
at_purgeif(struct ifnet *ifp)
{
        if_purgeaddrs(ifp, AF_APPLETALK, at_purgeaddr);
}

/*
 * Given an interface and an at_ifaddr (supposedly on that interface) remove
 * any routes that depend on this. Why ifp is needed I'm not sure, as
 * aa->at_ifaddr.ifa_ifp should be the same.
 */
static int
at_scrub(struct ifnet *ifp, struct at_ifaddr *aa)
{
        int error = 0;

        if (aa->aa_flags & AFA_ROUTE) {
                if (ifp->if_flags & IFF_LOOPBACK)
                        error = aa_delsingleroute(&aa->aa_ifa,
                            &aa->aa_addr.sat_addr, &aa->aa_netmask.sat_addr);
                else if (ifp->if_flags & IFF_POINTOPOINT)
                        error = rtinit(&aa->aa_ifa, RTM_DELETE, RTF_HOST);
                else if (ifp->if_flags & IFF_BROADCAST)
                        error = aa_dorangeroute(&aa->aa_ifa,
                            ntohs(aa->aa_firstnet), ntohs(aa->aa_lastnet),
                            RTM_DELETE);

                aa->aa_ifa.ifa_flags &= ~IFA_ROUTE;
                aa->aa_flags &= ~AFA_ROUTE;
        }
        return error;
}

/*
 * given an at_ifaddr,a sockaddr_at and an ifp,
 * bang them all together at high speed and see what happens
 */
static int
at_ifinit(struct ifnet *ifp, struct at_ifaddr *aa, const struct sockaddr_at *sat)
{
        struct netrange nr, onr;
        struct sockaddr_at oldaddr;
        int             s = splnet(), error = 0, i, j;
        int             netinc, nodeinc, nnets;
        u_short         net;

        /*
         * save the old addresses in the at_ifaddr just in case we need them.
         */
        oldaddr = aa->aa_addr;
        onr.nr_firstnet = aa->aa_firstnet;
        onr.nr_lastnet = aa->aa_lastnet;

        /*
         * take the address supplied as an argument, and add it to the
         * at_ifnet (also given). Remember ing to update
         * those parts of the at_ifaddr that need special processing
         */
        memset(AA_SAT(aa), 0, sizeof(struct sockaddr_at));
        memcpy(&nr, sat->sat_zero, sizeof(struct netrange));
        memcpy(AA_SAT(aa)->sat_zero, sat->sat_zero, sizeof(struct netrange));
        nnets = ntohs(nr.nr_lastnet) - ntohs(nr.nr_firstnet) + 1;
        aa->aa_firstnet = nr.nr_firstnet;
        aa->aa_lastnet = nr.nr_lastnet;

#ifdef NETATALKDEBUG
        printf("at_ifinit: %s: %u.%u range %u-%u phase %d\n",
            ifp->if_xname,
            ntohs(sat->sat_addr.s_net), sat->sat_addr.s_node,
            ntohs(aa->aa_firstnet), ntohs(aa->aa_lastnet),
            (aa->aa_flags & AFA_PHASE2) ? 2 : 1);
#endif

        /*
         * We could eliminate the need for a second phase 1 probe (post
         * autoconf) if we check whether we're resetting the node. Note
         * that phase 1 probes use only nodes, not net.node pairs.  Under
         * phase 2, both the net and node must be the same.
         */
        AA_SAT(aa)->sat_len = sizeof(struct sockaddr_at);
        AA_SAT(aa)->sat_family = AF_APPLETALK;
        if (ifp->if_flags & IFF_LOOPBACK) {
                AA_SAT(aa)->sat_addr.s_net = sat->sat_addr.s_net;
                AA_SAT(aa)->sat_addr.s_node = sat->sat_addr.s_node;
#if 0
        } else if (fp->if_flags & IFF_POINTOPOINT) {
                /* unimplemented */
                /*
                 * we'd have to copy the dstaddr field over from the sat
                 * but it's not clear that it would contain the right info..
                 */
#endif
        } else {
                /*
                 * We are a normal (probably ethernet) interface.
                 * apply the new address to the interface structures etc.
                 * We will probe this address on the net first, before
                 * applying it to ensure that it is free.. If it is not, then
                 * we will try a number of other randomly generated addresses
                 * in this net and then increment the net.  etc.etc. until
                 * we find an unused address.
                 */
                aa->aa_flags |= AFA_PROBING;    /* if not loopback we Must
                                                 * probe? */
                if (aa->aa_flags & AFA_PHASE2) {
                        if (sat->sat_addr.s_net == ATADDR_ANYNET) {
                                /*
                                 * If we are phase 2, and the net was not
                                 * specified * then we select a random net
                                 * within the supplied netrange.
                                 * XXX use /dev/random?
                                 */
                                if (nnets != 1) {
                                        net = ntohs(nr.nr_firstnet) +
                                            time_second % (nnets - 1);
                                } else {
                                        net = ntohs(nr.nr_firstnet);
                                }
                        } else {
                                /*
                                 * if a net was supplied, then check that it
                                 * is within the netrange. If it is not then
                                 * replace the old values and return an error
                                 */
                                if (ntohs(sat->sat_addr.s_net) <
                                    ntohs(nr.nr_firstnet) ||
                                    ntohs(sat->sat_addr.s_net) >
                                    ntohs(nr.nr_lastnet)) {
                                        aa->aa_addr = oldaddr;
                                        aa->aa_firstnet = onr.nr_firstnet;
                                        aa->aa_lastnet = onr.nr_lastnet;
                                        splx(s);
                                        return (EINVAL);
                                }
                                /*
                                 * otherwise just use the new net number..
                                 */
                                net = ntohs(sat->sat_addr.s_net);
                        }
                } else {
                        /*
                         * we must be phase one, so just use whatever we were
                         * given. I guess it really isn't going to be used...
                         * RIGHT?
                         */
                        net = ntohs(sat->sat_addr.s_net);
                }

                /*
                 * set the node part of the address into the ifaddr. If it's
                 * not specified, be random about it... XXX use /dev/random?
                 */
                if (sat->sat_addr.s_node == ATADDR_ANYNODE) {
                        AA_SAT(aa)->sat_addr.s_node = time_second;
                } else {
                        AA_SAT(aa)->sat_addr.s_node = sat->sat_addr.s_node;
                }

                /*
                 * step through the nets in the range starting at the
                 * (possibly random) start point.
                 */
                for (i = nnets, netinc = 1; i > 0; net = ntohs(nr.nr_firstnet) +
                     ((net - ntohs(nr.nr_firstnet) + netinc) % nnets), i--) {
                        AA_SAT(aa)->sat_addr.s_net = htons(net);

                        /*
                         * using a rather strange stepping method,
                         * stagger through the possible node addresses
                         * Once again, starting at the (possibly random)
                         * initial node address.
                         */
                        for (j = 0, nodeinc = time_second | 1; j < 256;
                             j++, AA_SAT(aa)->sat_addr.s_node += nodeinc) {
                                if (AA_SAT(aa)->sat_addr.s_node > 253 ||
                                    AA_SAT(aa)->sat_addr.s_node < 1) {
                                        continue;
                                }
                                aa->aa_probcnt = 10;

                                /*
                                 * start off the probes as an asynchronous
                                 * activity. though why wait 200mSec?
                                 */
                                callout_reset(&aa->aa_probe_ch, hz / 5,
                                    aarpprobe, ifp);
                                if (tsleep(aa, PPAUSE | PCATCH, "at_ifinit",
                                    0)) {
                                        /*
                                         * theoretically we shouldn't time out
                                         * here so if we returned with an error.
                                         */
                                        printf("at_ifinit: timeout?!\n");
                                        aa->aa_addr = oldaddr;
                                        aa->aa_firstnet = onr.nr_firstnet;
                                        aa->aa_lastnet = onr.nr_lastnet;
                                        splx(s);
                                        return (EINTR);
                                }
                                /*
                                 * The async activity should have woken us
                                 * up. We need to see if it was successful in
                                 * finding a free spot, or if we need to
                                 * iterate to the next address to try.
                                 */
                                if ((aa->aa_flags & AFA_PROBING) == 0)
                                        break;
                        }

                        /*
                         * of course we need to break out through two loops...
                         */
                        if ((aa->aa_flags & AFA_PROBING) == 0)
                                break;

                        /* reset node for next network */
                        AA_SAT(aa)->sat_addr.s_node = time_second;
                }

                /*
                 * if we are still trying to probe, then we have finished all
                 * the possible addresses, so we need to give up
                 */
                if (aa->aa_flags & AFA_PROBING) {
                        aa->aa_addr = oldaddr;
                        aa->aa_firstnet = onr.nr_firstnet;
                        aa->aa_lastnet = onr.nr_lastnet;
                        splx(s);
                        return (EADDRINUSE);
                }
        }

        /*
         * Now that we have selected an address, we need to tell the
         * interface about it, just in case it needs to adjust something.
         */
        if ((error = if_addr_init(ifp, &aa->aa_ifa, true)) != 0) {
                /*
                 * of course this could mean that it objects violently
                 * so if it does, we back out again..
                 */
                aa->aa_addr = oldaddr;
                aa->aa_firstnet = onr.nr_firstnet;
                aa->aa_lastnet = onr.nr_lastnet;
                splx(s);
                return (error);
        }
        /*
         * set up the netmask part of the at_ifaddr and point the appropriate
         * pointer in the ifaddr to it. probably pointless, but what the
         * heck.. XXX
         */
        memset(&aa->aa_netmask, 0, sizeof(aa->aa_netmask));
        aa->aa_netmask.sat_len = sizeof(struct sockaddr_at);
        aa->aa_netmask.sat_family = AF_APPLETALK;
        aa->aa_netmask.sat_addr.s_net = 0xffff;
        aa->aa_netmask.sat_addr.s_node = 0;
#if 0
        aa->aa_ifa.ifa_netmask = (struct sockaddr *) &(aa->aa_netmask);/* XXX */
#endif

        /*
         * Initialize broadcast (or remote p2p) address
         */
        memset(&aa->aa_broadaddr, 0, sizeof(aa->aa_broadaddr));
        aa->aa_broadaddr.sat_len = sizeof(struct sockaddr_at);
        aa->aa_broadaddr.sat_family = AF_APPLETALK;

        aa->aa_ifa.ifa_metric = ifp->if_metric;
        if (ifp->if_flags & IFF_BROADCAST) {
                aa->aa_broadaddr.sat_addr.s_net = htons(ATADDR_ANYNET);
                aa->aa_broadaddr.sat_addr.s_node = ATADDR_BCAST;
                aa->aa_ifa.ifa_broadaddr =
                    (struct sockaddr *) &aa->aa_broadaddr;
                /* add the range of routes needed */
                error = aa_dorangeroute(&aa->aa_ifa,
                    ntohs(aa->aa_firstnet), ntohs(aa->aa_lastnet), RTM_ADD);
        } else if (ifp->if_flags & IFF_POINTOPOINT) {
                struct at_addr  rtaddr, rtmask;

                memset(&rtaddr, 0, sizeof(rtaddr));
                memset(&rtmask, 0, sizeof(rtmask));
                /* fill in the far end if we know it here XXX */
                aa->aa_ifa.ifa_dstaddr = (struct sockaddr *) & aa->aa_dstaddr;
                error = aa_addsingleroute(&aa->aa_ifa, &rtaddr, &rtmask);
        } else if (ifp->if_flags & IFF_LOOPBACK) {
                struct at_addr  rtaddr, rtmask;

                memset(&rtaddr, 0, sizeof(rtaddr));
                memset(&rtmask, 0, sizeof(rtmask));
                rtaddr.s_net = AA_SAT(aa)->sat_addr.s_net;
                rtaddr.s_node = AA_SAT(aa)->sat_addr.s_node;
                rtmask.s_net = 0xffff;
                rtmask.s_node = 0x0;
                error = aa_addsingleroute(&aa->aa_ifa, &rtaddr, &rtmask);
        }
        /*
         * of course if we can't add these routes we back out, but it's getting
         * risky by now XXX
         */
        if (error) {
                at_scrub(ifp, aa);
                aa->aa_addr = oldaddr;
                aa->aa_firstnet = onr.nr_firstnet;
                aa->aa_lastnet = onr.nr_lastnet;
                splx(s);
                return (error);
        }
        /*
         * note that the address has a route associated with it....
         */
        aa->aa_ifa.ifa_flags |= IFA_ROUTE;
        aa->aa_flags |= AFA_ROUTE;
        splx(s);
        return (0);
}

/*
 * check whether a given address is a broadcast address for us..
 */
int
at_broadcast(const struct sockaddr_at *sat)
{
        struct at_ifaddr *aa;

        /*
         * If the node is not right, it can't be a broadcast
         */
        if (sat->sat_addr.s_node != ATADDR_BCAST)
                return 0;

        /*
         * If the node was right then if the net is right, it's a broadcast
         */
        if (sat->sat_addr.s_net == ATADDR_ANYNET)
                return 1;

        /*
         * failing that, if the net is one we have, it's a broadcast as well.
         */
        TAILQ_FOREACH(aa, &at_ifaddr, aa_list) {
                if ((aa->aa_ifp->if_flags & IFF_BROADCAST)
                    && (ntohs(sat->sat_addr.s_net) >= ntohs(aa->aa_firstnet)
                  && ntohs(sat->sat_addr.s_net) <= ntohs(aa->aa_lastnet)))
                        return 1;
        }
        return 0;
}


/*
 * aa_dorangeroute()
 *
 * Add a route for a range of networks from bot to top - 1.
 * Algorithm:
 *
 * Split the range into two subranges such that the middle
 * of the two ranges is the point where the highest bit of difference
 * between the two addresses, makes its transition
 * Each of the upper and lower ranges might not exist, or might be
 * representable by 1 or more netmasks. In addition, if both
 * ranges can be represented by the same netmask, then teh can be merged
 * by using the next higher netmask..
 */

static int
aa_dorangeroute(struct ifaddr *ifa, u_int bot, u_int top, int cmd)
{
        u_int           mask1;
        struct at_addr  addr;
        struct at_addr  mask;
        int             error;

        /*
         * slight sanity check
         */
        if (bot > top)
                return (EINVAL);

        addr.s_node = 0;
        mask.s_node = 0;
        /*
         * just start out with the lowest boundary
         * and keep extending the mask till it's too big.
         */

        while (bot <= top) {
                mask1 = 1;
                while (((bot & ~mask1) >= bot)
                       && ((bot | mask1) <= top)) {
                        mask1 <<= 1;
                        mask1 |= 1;
                }
                mask1 >>= 1;
                mask.s_net = htons(~mask1);
                addr.s_net = htons(bot);
                if (cmd == RTM_ADD) {
                        error = aa_addsingleroute(ifa, &addr, &mask);
                        if (error) {
                                /* XXX clean up? */
                                return (error);
                        }
                } else {
                        error = aa_delsingleroute(ifa, &addr, &mask);
                }
                bot = (bot | mask1) + 1;
        }
        return 0;
}

static int
aa_addsingleroute(struct ifaddr *ifa, struct at_addr *addr, struct at_addr *mask)
{
        int error;

#ifdef NETATALKDEBUG
        printf("aa_addsingleroute: %x.%x mask %x.%x ...",
               ntohs(addr->s_net), addr->s_node,
               ntohs(mask->s_net), mask->s_node);
#endif

        error = aa_dosingleroute(ifa, addr, mask, RTM_ADD, RTF_UP);
#ifdef NETATALKDEBUG
        if (error)
                printf("aa_addsingleroute: error %d\n", error);
#endif
        return (error);
}

static int
aa_delsingleroute(struct ifaddr *ifa, struct at_addr *addr, struct at_addr *mask)
{
        int error;

#ifdef NETATALKDEBUG
        printf("aa_delsingleroute: %x.%x mask %x.%x ...",
               ntohs(addr->s_net), addr->s_node,
               ntohs(mask->s_net), mask->s_node);
#endif

        error = aa_dosingleroute(ifa, addr, mask, RTM_DELETE, 0);
#ifdef NETATALKDEBUG
        if (error)
                printf("aa_delsingleroute: error %d\n", error);
#endif
        return (error);
}

static int
aa_dosingleroute(struct ifaddr *ifa, struct at_addr *at_addr, struct at_addr *at_mask, int cmd, int flags)
{
        struct sockaddr_at addr, mask, *gate;

        memset(&addr, 0, sizeof(addr));
        memset(&mask, 0, sizeof(mask));
        addr.sat_family = AF_APPLETALK;
        addr.sat_len = sizeof(struct sockaddr_at);
        addr.sat_addr.s_net = at_addr->s_net;
        addr.sat_addr.s_node = at_addr->s_node;
        mask.sat_family = AF_APPLETALK;
        mask.sat_len = sizeof(struct sockaddr_at);
        mask.sat_addr.s_net = at_mask->s_net;
        mask.sat_addr.s_node = at_mask->s_node;

        if (at_mask->s_node) {
                gate = satosat(ifa->ifa_dstaddr);
                flags |= RTF_HOST;
        } else {
                gate = satosat(ifa->ifa_addr);
        }

#ifdef NETATALKDEBUG
        printf("on %s %x.%x\n", (flags & RTF_HOST) ? "host" : "net",
               ntohs(gate->sat_addr.s_net), gate->sat_addr.s_node);
#endif
        return (rtrequest(cmd, (struct sockaddr *) &addr,
            (struct sockaddr *) gate, (struct sockaddr *) &mask, flags, NULL));
}

#if 0
static void
aa_clean(void)
{
        struct at_ifaddr *aa;
        struct ifaddr  *ifa;
        struct ifnet   *ifp;

        while ((aa = TAILQ_FIRST(&at_ifaddr)) != NULL) {
                TAILQ_REMOVE(&at_ifaddr, aa, aa_list);
                ifp = aa->aa_ifp;
                at_scrub(ifp, aa);
                IFADDR_READER_FOREACH(ifa, ifp) {
                        if (ifa == &aa->aa_ifa)
                                break;
                }
                if (ifa == NULL)
                        panic("aa not present");
                ifa_remove(ifp, ifa);
        }
}
#endif