/*-
 * Copyright (c) 2014 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Mindaugas Rasiukevicius.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. 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 FOUNDATION 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.
 */

/*
 * NPF network interface handling module.
 */

#ifdef _KERNEL
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: npf_ifaddr.c,v 1.8 2022/02/13 19:20:11 riastradh Exp $");

#include <sys/param.h>
#include <sys/types.h>
#include <sys/kmem.h>

#include <net/if.h>
#include <netinet/in.h>
#include <netinet6/in6_var.h>
#endif

#include "npf_impl.h"

static npf_table_t *
lookup_ifnet_table(npf_t *npf, ifnet_t *ifp)
{
        const npf_ifops_t *ifops = npf->ifops;
        char tname[NPF_TABLE_MAXNAMELEN];
        const char *ifname;
        npf_config_t *nc;
        npf_table_t *t;
        unsigned tid;

        /* Get the interface name and prefix it. */
        ifname = ifops->getname(npf, ifp);
        snprintf(tname, sizeof(tname), ".ifnet-%s", ifname);

        KERNEL_LOCK(1, NULL);
        nc = npf_config_enter(npf);

        /*
         * Check whether this interface is of any interest to us.
         */
        t = npf_tableset_getbyname(nc->tableset, tname);
        if (!t) {
                goto out;
        }
        tid = npf_table_getid(t);

        /* Create a new NPF table for the interface. */
        t = npf_table_create(tname, tid, NPF_TABLE_IFADDR, NULL, 0);
        if (!t) {
                goto out;
        }
        return t;
out:
        npf_config_exit(npf);
        KERNEL_UNLOCK_ONE(NULL);
        return NULL;
}

static void
replace_ifnet_table(npf_t *npf, npf_table_t *newt)
{
        npf_tableset_t *ts = atomic_load_relaxed(&npf->config)->tableset;
        npf_table_t *oldt;

        KASSERT(npf_config_locked_p(npf));

        KERNEL_UNLOCK_ONE(NULL);

        /*
         * Finally, swap the tables and issue a sync barrier.
         */
        oldt = npf_tableset_swap(ts, newt);
        npf_config_sync(npf);
        npf_config_exit(npf);

        /* At this point, it is safe to destroy the old table. */
        npf_table_destroy(oldt);
}

void
npf_ifaddr_sync(npf_t *npf, ifnet_t *ifp)
{
        npf_table_t *t;
        struct ifaddr *ifa;

        /*
         * First, check whether this interface is of any interest to us.
         *
         * => Acquires npf-config-lock and kernel-lock on success.
         */
        t = lookup_ifnet_table(npf, ifp);
        if (!t)
                return;

        /*
         * Populate the table with the interface addresses.
         * Note: currently, this list is protected by the kernel-lock.
         */
        IFADDR_FOREACH(ifa, ifp) {
                struct sockaddr *sa = ifa->ifa_addr;
                const void *p = NULL;
                int alen = 0;

                if (sa->sa_family == AF_INET) {
                        const struct sockaddr_in *sin4 = satosin(sa);
                        alen = sizeof(struct in_addr);
                        p = &sin4->sin_addr;
                }
                if (sa->sa_family == AF_INET6) {
                        const struct sockaddr_in6 *sin6 = satosin6(sa);
                        alen = sizeof(struct in6_addr);
                        p = &sin6->sin6_addr;
                }
                if (alen) {
                        npf_addr_t addr;
                        memcpy(&addr, p, alen);
                        npf_table_insert(t, alen, &addr, NPF_NO_NETMASK);
                }
        }

        /* Publish the new table. */
        replace_ifnet_table(npf, t);
}

void
npf_ifaddr_flush(npf_t *npf, ifnet_t *ifp)
{
        npf_table_t *t;

        /*
         * Flush: just load an empty table.
         */
        t = lookup_ifnet_table(npf, ifp);
        if (!t) {
                return;
        }
        replace_ifnet_table(npf, t);
}

void
npf_ifaddr_syncall(npf_t *npf)
{
        ifnet_t *ifp;

        KERNEL_LOCK(1, NULL);
        IFNET_GLOBAL_LOCK();
        IFNET_WRITER_FOREACH(ifp) {
                npf_ifaddr_sync(npf, ifp);
        }
        IFNET_GLOBAL_UNLOCK();
        KERNEL_UNLOCK_ONE(NULL);
}