/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2020 Alexander V. Chernikov
 *
 * 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 AUTHOR 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 AUTHOR 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.
 */

#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#include "opt_route.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rmlock.h>

#include <net/if.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/if_dl.h>
#include <net/vnet.h>
#include <net/route.h>
#include <net/route/route_ctl.h>
#include <net/route/route_var.h>
#include <net/route/nhop_utils.h>
#include <net/route/nhop.h>
#include <net/route/nhop_var.h>
#include <netinet/in.h>
#include <netinet6/scope6_var.h>
#include <netinet6/in6_var.h>

#define DEBUG_MOD_NAME  route_ctl
#define DEBUG_MAX_LEVEL LOG_DEBUG
#include <net/route/route_debug.h>
_DECLARE_DEBUG(LOG_INFO);

/*
 * This file contains control plane routing tables functions.
 *
 * All functions assumes they are called in net epoch.
 */

union sockaddr_union {
        struct sockaddr         sa;
        struct sockaddr_in      sin;
        struct sockaddr_in6     sin6;
        char                    _buf[32];
};

static int add_route_byinfo(struct rib_head *rnh, struct rt_addrinfo *info,
    struct rib_cmd_info *rc);
static int change_route_byinfo(struct rib_head *rnh, struct rtentry *rt,
    struct rt_addrinfo *info, struct route_nhop_data *nhd_orig,
    struct rib_cmd_info *rc);

static int add_route_flags(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd_add, int op_flags, struct rib_cmd_info *rc);
static int add_route_flags_mpath(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd_add, struct route_nhop_data *rnd_orig,
    int op_flags, struct rib_cmd_info *rc);

static int add_route(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd, struct rib_cmd_info *rc);
static int delete_route(struct rib_head *rnh, struct rtentry *rt,
    struct rib_cmd_info *rc);
static int rt_delete_conditional(struct rib_head *rnh, struct rtentry *rt,
    int prio, rib_filter_f_t *cb, void *cbdata, struct rib_cmd_info *rc);

static bool fill_pxmask_family(int family, int plen, struct sockaddr *_dst,
    struct sockaddr **pmask);
static int get_prio_from_info(const struct rt_addrinfo *info);
static int nhop_get_prio(const struct nhop_object *nh);

static bool rib_can_multipath(struct rib_head *rh);

/* Per-vnet multipath routing configuration */
SYSCTL_DECL(_net_route);
#define V_rib_route_multipath   VNET(rib_route_multipath)
VNET_DEFINE(u_int, rib_route_multipath) = 1;
SYSCTL_UINT(_net_route, OID_AUTO, multipath, CTLFLAG_RW | CTLFLAG_VNET,
    &VNET_NAME(rib_route_multipath), 0, "Enable route multipath");

VNET_DEFINE(u_int, fib_hash_outbound) = 0;
SYSCTL_UINT(_net_route, OID_AUTO, hash_outbound, CTLFLAG_RD | CTLFLAG_VNET,
    &VNET_NAME(fib_hash_outbound), 0,
    "Compute flowid for locally-originated packets");

/* Default entropy to add to the hash calculation for the outbound connections*/
uint8_t mpath_entropy_key[MPATH_ENTROPY_KEY_LEN] = {
        0x6d, 0x5a, 0x56, 0xda, 0x25, 0x5b, 0x0e, 0xc2,
        0x41, 0x67, 0x25, 0x3d, 0x43, 0xa3, 0x8f, 0xb0,
        0xd0, 0xca, 0x2b, 0xcb, 0xae, 0x7b, 0x30, 0xb4,
        0x77, 0xcb, 0x2d, 0xa3, 0x80, 0x30, 0xf2, 0x0c,
        0x6a, 0x42, 0xb7, 0x3b, 0xbe, 0xac, 0x01, 0xfa,
};

#if defined(INET) && defined(INET6)
FEATURE(ipv4_rfc5549_support, "Route IPv4 packets via IPv6 nexthops");
#define V_rib_route_ipv6_nexthop VNET(rib_route_ipv6_nexthop)
VNET_DEFINE_STATIC(u_int, rib_route_ipv6_nexthop) = 1;
SYSCTL_UINT(_net_route, OID_AUTO, ipv6_nexthop, CTLFLAG_RW | CTLFLAG_VNET,
    &VNET_NAME(rib_route_ipv6_nexthop), 0, "Enable IPv4 route via IPv6 Next Hop address");
#endif

/* Debug bits */
SYSCTL_NODE(_net_route, OID_AUTO, debug, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "");

static struct rib_head *
get_rnh(uint32_t fibnum, const struct rt_addrinfo *info)
{
        struct rib_head *rnh;
        struct sockaddr *dst;

        KASSERT((fibnum < rt_numfibs), ("rib_add_route: bad fibnum"));

        dst = info->rti_info[RTAX_DST];
        rnh = rt_tables_get_rnh(fibnum, dst->sa_family);

        return (rnh);
}

#if defined(INET) && defined(INET6)
bool
rib_can_4o6_nhop(void)
{
        return (!!V_rib_route_ipv6_nexthop);
}
#endif

static bool
rib_can_multipath(struct rib_head *rh)
{
        int result;

        CURVNET_SET(rh->rib_vnet);
        result = !!V_rib_route_multipath;
        CURVNET_RESTORE();

        return (result);
}

/*
 * Check is nhop is multipath-eligible.
 * Avoid nhops without gateways and redirects.
 *
 * Returns 1 for multipath-eligible nexthop,
 * 0 otherwise.
 */
bool
nhop_can_multipath(const struct nhop_object *nh)
{

        if ((nh->nh_flags & NHF_MULTIPATH) != 0)
                return (1);
        if ((nh->nh_flags & NHF_GATEWAY) == 0)
                return (0);
        if ((nh->nh_flags & NHF_REDIRECT) != 0)
                return (0);

        return (1);
}

static int
get_info_weight(const struct rt_addrinfo *info, uint32_t default_weight)
{
        uint32_t weight;

        if (info->rti_mflags & RTV_WEIGHT)
                weight = info->rti_rmx->rmx_weight;
        else
                weight = default_weight;
        if (weight == 0)
                weight = default_weight;

        return (weight);
}

/*
 * File-local concept for distingushing between the normal and
 * RTF_PINNED routes tha can override the "normal" one.
 */
#define NH_PRIORITY_HIGH        2
#define NH_PRIORITY_NORMAL      1
static int
get_prio_from_info(const struct rt_addrinfo *info)
{
        if (info->rti_flags & RTF_PINNED)
                return (NH_PRIORITY_HIGH);
        return (NH_PRIORITY_NORMAL);
}

static int
nhop_get_prio(const struct nhop_object *nh)
{
        if (NH_IS_PINNED(nh))
                return (NH_PRIORITY_HIGH);
        return (NH_PRIORITY_NORMAL);
}

/*
 * Check if specified @gw matches gw data in the nexthop @nh.
 *
 * Returns true if matches, false otherwise.
 */
bool
match_nhop_gw(const struct nhop_object *nh, const struct sockaddr *gw)
{

        if (nh->gw_sa.sa_family != gw->sa_family)
                return (false);

        switch (gw->sa_family) {
        case AF_INET:
                return (nh->gw4_sa.sin_addr.s_addr ==
                    ((const struct sockaddr_in *)gw)->sin_addr.s_addr);
        case AF_INET6:
                {
                        const struct sockaddr_in6 *gw6;
                        gw6 = (const struct sockaddr_in6 *)gw;

                        /*
                         * Currently (2020-09) IPv6 gws in kernel have their
                         * scope embedded. Once this becomes false, this code
                         * has to be revisited.
                         */
                        if (IN6_ARE_ADDR_EQUAL(&nh->gw6_sa.sin6_addr,
                            &gw6->sin6_addr))
                                return (true);
                        return (false);
                }
        case AF_LINK:
                {
                        const struct sockaddr_dl *sdl;
                        sdl = (const struct sockaddr_dl *)gw;
                        return (nh->gwl_sa.sdl_index == sdl->sdl_index);
                }
        default:
                return (memcmp(&nh->gw_sa, gw, nh->gw_sa.sa_len) == 0);
        }

        /* NOTREACHED */
        return (false);
}

/*
 * Matches all nexthop with given @gw.
 * Can be used as rib_filter_f callback.
 */
int
rib_match_gw(const struct rtentry *rt, const struct nhop_object *nh, void *gw_sa)
{
        const struct sockaddr *gw = (const struct sockaddr *)gw_sa;

        return (match_nhop_gw(nh, gw));
}

struct gw_filter_data {
        const struct sockaddr *gw;
        int count;
};

/*
 * Matches first occurence of the gateway provided in @gwd
 */
static int
match_gw_one(const struct rtentry *rt, const struct nhop_object *nh, void *_data)
{
        struct gw_filter_data *gwd = (struct gw_filter_data *)_data;

        /* Return only first match to make rtsock happy */
        if (match_nhop_gw(nh, gwd->gw) && gwd->count++ == 0)
                return (1);
        return (0);
}

/*
 * Checks if data in @info matches nexhop @nh.
 *
 * Returns 0 on success,
 * ESRCH if not matched,
 * ENOENT if filter function returned false
 */
int
check_info_match_nhop(const struct rt_addrinfo *info, const struct rtentry *rt,
    const struct nhop_object *nh)
{
        const struct sockaddr *gw = info->rti_info[RTAX_GATEWAY];

        if (info->rti_filter != NULL) {
            if (info->rti_filter(rt, nh, info->rti_filterdata) == 0)
                    return (ENOENT);
            else
                    return (0);
        }
        if ((gw != NULL) && !match_nhop_gw(nh, gw))
                return (ESRCH);

        return (0);
}

/*
 * Runs exact prefix match based on @dst and @netmask.
 * Returns matched @rtentry if found or NULL.
 * If rtentry was found, saves nexthop / weight value into @rnd.
 */
static struct rtentry *
lookup_prefix_bysa(struct rib_head *rnh, const struct sockaddr *dst,
    const struct sockaddr *netmask, struct route_nhop_data *rnd)
{
        struct rtentry *rt;

        RIB_LOCK_ASSERT(rnh);

        rt = (struct rtentry *)rnh->rnh_lookup(dst, netmask, &rnh->head);
        if (rt != NULL) {
                rnd->rnd_nhop = rt->rt_nhop;
                rnd->rnd_weight = rt->rt_weight;
        } else {
                rnd->rnd_nhop = NULL;
                rnd->rnd_weight = 0;
        }

        return (rt);
}

struct rtentry *
lookup_prefix_rt(struct rib_head *rnh, const struct rtentry *rt,
    struct route_nhop_data *rnd)
{
        return (lookup_prefix_bysa(rnh, rt_key_const(rt), rt_mask_const(rt), rnd));
}

/*
 * Runs exact prefix match based on dst/netmask from @info.
 * Assumes RIB lock is held.
 * Returns matched @rtentry if found or NULL.
 * If rtentry was found, saves nexthop / weight value into @rnd.
 */
struct rtentry *
lookup_prefix(struct rib_head *rnh, const struct rt_addrinfo *info,
    struct route_nhop_data *rnd)
{
        struct rtentry *rt;

        rt = lookup_prefix_bysa(rnh, info->rti_info[RTAX_DST],
            info->rti_info[RTAX_NETMASK], rnd);

        return (rt);
}

const struct rtentry *
rib_lookup_prefix_plen(struct rib_head *rnh, struct sockaddr *dst, int plen,
    struct route_nhop_data *rnd)
{
        union sockaddr_union mask_storage;
        struct sockaddr *netmask = &mask_storage.sa;

        if (fill_pxmask_family(dst->sa_family, plen, dst, &netmask))
                return (lookup_prefix_bysa(rnh, dst, netmask, rnd));
        return (NULL);
}

static bool
fill_pxmask_family(int family, int plen, struct sockaddr *_dst,
    struct sockaddr **pmask)
{
        if (plen == -1) {
                *pmask = NULL;
                return (true);
        }

        switch (family) {
#ifdef INET
        case AF_INET:
                {
                        struct sockaddr_in *mask = (struct sockaddr_in *)(*pmask);
                        struct sockaddr_in *dst= (struct sockaddr_in *)_dst;

                        memset(mask, 0, sizeof(*mask));
                        mask->sin_family = family;
                        mask->sin_len = sizeof(*mask);
                        if (plen == 32)
                                *pmask = NULL;
                        else if (plen > 32 || plen < 0)
                                return (false);
                        else {
                                uint32_t daddr, maddr;
                                maddr = htonl(plen ? ~((1 << (32 - plen)) - 1) : 0);
                                mask->sin_addr.s_addr = maddr;
                                daddr = dst->sin_addr.s_addr;
                                daddr = htonl(ntohl(daddr) & ntohl(maddr));
                                dst->sin_addr.s_addr = daddr;
                        }
                        return (true);
                }
                break;
#endif
#ifdef INET6
        case AF_INET6:
                {
                        struct sockaddr_in6 *mask = (struct sockaddr_in6 *)(*pmask);
                        struct sockaddr_in6 *dst = (struct sockaddr_in6 *)_dst;

                        memset(mask, 0, sizeof(*mask));
                        mask->sin6_family = family;
                        mask->sin6_len = sizeof(*mask);
                        if (plen == 128)
                                *pmask = NULL;
                        else if (plen > 128 || plen < 0)
                                return (false);
                        else {
                                ip6_writemask(&mask->sin6_addr, plen);
                                IN6_MASK_ADDR(&dst->sin6_addr, &mask->sin6_addr);
                        }
                        return (true);
                }
                break;
#endif
        }
        return (false);
}

/*
 * Attempts to add @dst/plen prefix with nexthop/nexhopgroup data @rnd
 * to the routing table.
 *
 * @fibnum: verified kernel rtable id to insert route to
 * @dst: verified kernel-originated sockaddr, can be masked if plen non-empty
 * @plen: prefix length (or -1 if host route or not applicable for AF)
 * @op_flags: combination of RTM_F_ flags
 * @rc: storage to report operation result
 *
 * Returns 0 on success.
 */
int
rib_add_route_px(uint32_t fibnum, struct sockaddr *dst, int plen,
    struct route_nhop_data *rnd, int op_flags, struct rib_cmd_info *rc)
{
        union sockaddr_union mask_storage;
        struct sockaddr *netmask = &mask_storage.sa;
        struct rtentry *rt = NULL;

        NET_EPOCH_ASSERT();

        bzero(rc, sizeof(struct rib_cmd_info));
        rc->rc_cmd = RTM_ADD;

        struct rib_head *rnh = rt_tables_get_rnh(fibnum, dst->sa_family);
        if (rnh == NULL)
                return (EAFNOSUPPORT);

        if (!fill_pxmask_family(dst->sa_family, plen, dst, &netmask)) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: invalid plen %d", plen);
                return (EINVAL);
        }

        if (op_flags & RTM_F_CREATE) {
                if ((rt = rt_alloc(rnh, dst, netmask)) == NULL) {
                        FIB_RH_LOG(LOG_INFO, rnh, "rtentry allocation failed");
                        return (ENOMEM);
                }
        } else {
                struct route_nhop_data rnd_tmp;
                RIB_RLOCK_TRACKER;

                RIB_RLOCK(rnh);
                rt = lookup_prefix_bysa(rnh, dst, netmask, &rnd_tmp);
                RIB_RUNLOCK(rnh);

                if (rt == NULL)
                        return (ESRCH);
        }

        return (add_route_flags(rnh, rt, rnd, op_flags, rc));
}

/*
 * Attempts to delete @dst/plen prefix matching gateway @gw from the
 *  routing rable.
 *
 * @fibnum: rtable id to remove route from
 * @dst: verified kernel-originated sockaddr, can be masked if plen non-empty
 * @plen: prefix length (or -1 if host route or not applicable for AF)
 * @gw: gateway to match
 * @op_flags: combination of RTM_F_ flags
 * @rc: storage to report operation result
 *
 * Returns 0 on success.
 */
int
rib_del_route_px_gw(uint32_t fibnum, struct sockaddr *dst, int plen,
    const struct sockaddr *gw, int op_flags, struct rib_cmd_info *rc)
{
        struct gw_filter_data gwd = { .gw = gw };

        return (rib_del_route_px(fibnum, dst, plen, match_gw_one, &gwd, op_flags, rc));
}

/*
 * Attempts to delete @dst/plen prefix matching @filter_func from the
 *  routing rable.
 *
 * @fibnum: rtable id to remove route from
 * @dst: verified kernel-originated sockaddr, can be masked if plen non-empty
 * @plen: prefix length (or -1 if host route or not applicable for AF)
 * @filter_func: func to be called for each nexthop of the prefix for matching
 * @filter_arg: argument to pass to @filter_func
 * @op_flags: combination of RTM_F_ flags
 * @rc: storage to report operation result
 *
 * Returns 0 on success.
 */
int
rib_del_route_px(uint32_t fibnum, struct sockaddr *dst, int plen,
    rib_filter_f_t *filter_func, void *filter_arg, int op_flags,
    struct rib_cmd_info *rc)
{
        union sockaddr_union mask_storage;
        struct sockaddr *netmask = &mask_storage.sa;
        int error;

        NET_EPOCH_ASSERT();

        bzero(rc, sizeof(struct rib_cmd_info));
        rc->rc_cmd = RTM_DELETE;

        struct rib_head *rnh = rt_tables_get_rnh(fibnum, dst->sa_family);
        if (rnh == NULL)
                return (EAFNOSUPPORT);

        if (dst->sa_len > sizeof(mask_storage)) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: dst->sa_len too big: %d", dst->sa_len);
                return (EINVAL);
        }

        if (!fill_pxmask_family(dst->sa_family, plen, dst, &netmask)) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: invalid plen %d", plen);
                return (EINVAL);
        }

        int prio = (op_flags & RTM_F_FORCE) ? NH_PRIORITY_HIGH : NH_PRIORITY_NORMAL;

        RIB_WLOCK(rnh);
        struct route_nhop_data rnd;
        struct rtentry *rt = lookup_prefix_bysa(rnh, dst, netmask, &rnd);
        if (rt != NULL) {
                error = rt_delete_conditional(rnh, rt, prio, filter_func,
                    filter_arg, rc);
        } else
                error = ESRCH;
        RIB_WUNLOCK(rnh);

        if (error != 0)
                return (error);

        rib_notify(rnh, RIB_NOTIFY_DELAYED, rc);

        if (rc->rc_cmd == RTM_DELETE)
                rt_free(rc->rc_rt);
        else {
                /*
                 * Deleting 1 path may result in RTM_CHANGE to
                 * a different mpath group/nhop.
                 * Free old mpath group.
                 */
                nhop_free_any(rc->rc_nh_old);
        }

        return (0);
}

/*
 * Tries to copy route @rt from one rtable to the rtable specified by @dst_rh.
 * @rt: route to copy.
 * @rnd_src: nhop and weight. Multipath routes are not supported
 * @rh_dst: target rtable.
 * @rc: operation result storage
 *
 * Return 0 on success.
 */
int
rib_copy_route(struct rtentry *rt, const struct route_nhop_data *rnd_src,
    struct rib_head *rh_dst, struct rib_cmd_info *rc)
{
        struct nhop_object __diagused *nh_src = rnd_src->rnd_nhop;
        int error;

        MPASS((nh_src->nh_flags & NHF_MULTIPATH) == 0);

        IF_DEBUG_LEVEL(LOG_DEBUG2) {
                char nhbuf[NHOP_PRINT_BUFSIZE], rtbuf[NHOP_PRINT_BUFSIZE];
                nhop_print_buf_any(nh_src, nhbuf, sizeof(nhbuf));
                rt_print_buf(rt, rtbuf, sizeof(rtbuf));
                FIB_RH_LOG(LOG_DEBUG2, rh_dst, "copying %s -> %s from fib %u",
                    rtbuf, nhbuf, nhop_get_fibnum(nh_src));
        }
        struct nhop_object *nh = nhop_alloc(rh_dst->rib_fibnum, rh_dst->rib_family);
        if (nh == NULL) {
                FIB_RH_LOG(LOG_INFO, rh_dst, "unable to allocate new nexthop");
                return (ENOMEM);
        }
        nhop_copy(nh, rnd_src->rnd_nhop);
        nhop_set_origin(nh, nhop_get_origin(rnd_src->rnd_nhop));
        nhop_set_fibnum(nh, rh_dst->rib_fibnum);
        nh = nhop_get_nhop_internal(rh_dst, nh, &error);
        if (error != 0) {
                FIB_RH_LOG(LOG_INFO, rh_dst,
                    "unable to finalize new nexthop: error %d", error);
                return (ENOMEM);
        }

        struct rtentry *rt_new = rt_alloc(rh_dst, rt_key(rt), rt_mask(rt));
        if (rt_new == NULL) {
                FIB_RH_LOG(LOG_INFO, rh_dst, "unable to create new rtentry");
                nhop_free(nh);
                return (ENOMEM);
        }

        struct route_nhop_data rnd = {
                .rnd_nhop = nh,
                .rnd_weight = rnd_src->rnd_weight
        };
        int op_flags = RTM_F_CREATE | (NH_IS_PINNED(nh) ? RTM_F_FORCE : 0);
        error = add_route_flags(rh_dst, rt_new, &rnd, op_flags, rc);

        if (error != 0) {
                IF_DEBUG_LEVEL(LOG_DEBUG2) {
                        char buf[NHOP_PRINT_BUFSIZE];
                        rt_print_buf(rt, buf, sizeof(buf));
                        FIB_RH_LOG(LOG_DEBUG, rh_dst,
                            "Unable to add route %s: error %d", buf, error);
                }
                nhop_free(nh);
        }
        return (error);
}

/*
 * Adds route defined by @info into the kernel table specified by @fibnum and
 * sa_family in @info->rti_info[RTAX_DST].
 *
 * Returns 0 on success and fills in operation metadata into @rc.
 */
int
rib_add_route(uint32_t fibnum, struct rt_addrinfo *info,
    struct rib_cmd_info *rc)
{
        struct rib_head *rnh;
        int error;

        NET_EPOCH_ASSERT();

        rnh = get_rnh(fibnum, info);
        if (rnh == NULL)
                return (EAFNOSUPPORT);

        /*
         * Check consistency between RTF_HOST flag and netmask
         * existence.
         */
        if (info->rti_flags & RTF_HOST)
                info->rti_info[RTAX_NETMASK] = NULL;
        else if (info->rti_info[RTAX_NETMASK] == NULL) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: no RTF_HOST and empty netmask");
                return (EINVAL);
        }

        bzero(rc, sizeof(struct rib_cmd_info));
        rc->rc_cmd = RTM_ADD;

        error = add_route_byinfo(rnh, info, rc);
        if (error == 0)
                rib_notify(rnh, RIB_NOTIFY_DELAYED, rc);

        return (error);
}

static int
add_route_byinfo(struct rib_head *rnh, struct rt_addrinfo *info,
    struct rib_cmd_info *rc)
{
        struct route_nhop_data rnd_add;
        struct nhop_object *nh;
        struct rtentry *rt;
        struct sockaddr *dst, *gateway, *netmask;
        int error;

        dst = info->rti_info[RTAX_DST];
        gateway = info->rti_info[RTAX_GATEWAY];
        netmask = info->rti_info[RTAX_NETMASK];

        if ((info->rti_flags & RTF_GATEWAY) && !gateway) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: RTF_GATEWAY set with empty gw");
                return (EINVAL);
        }
        if (dst && gateway && !nhop_check_gateway(dst->sa_family, gateway->sa_family)) {
                FIB_RH_LOG(LOG_DEBUG, rnh,
                    "error: invalid dst/gateway family combination (%d, %d)",
                    dst->sa_family, gateway->sa_family);
                return (EINVAL);
        }

        if (dst->sa_len > sizeof(((struct rtentry *)NULL)->rt_dstb)) {
                FIB_RH_LOG(LOG_DEBUG, rnh, "error: dst->sa_len too large: %d",
                    dst->sa_len);
                return (EINVAL);
        }

        if (info->rti_ifa == NULL) {
                error = rt_getifa_fib(info, rnh->rib_fibnum);
                if (error)
                        return (error);
        }

        if ((rt = rt_alloc(rnh, dst, netmask)) == NULL)
                return (ENOBUFS);

        error = nhop_create_from_info(rnh, info, &nh);
        if (error != 0) {
                rt_free_immediate(rt);
                return (error);
        }

        rnd_add.rnd_nhop = nh;
        rnd_add.rnd_weight = get_info_weight(info, RT_DEFAULT_WEIGHT);

        int op_flags = RTM_F_CREATE;

        /*
         * Set the desired action when the route already exists:
         * If RTF_PINNED is present, assume the direct kernel routes that cannot be multipath.
         * Otherwise, append the path.
         */
        op_flags |= (info->rti_flags & RTF_PINNED) ? RTM_F_REPLACE : RTM_F_APPEND;

        return (add_route_flags(rnh, rt, &rnd_add, op_flags, rc));
}

static int
add_route_flags(struct rib_head *rnh, struct rtentry *rt, struct route_nhop_data *rnd_add,
    int op_flags, struct rib_cmd_info *rc)
{
        struct route_nhop_data rnd_orig;
        struct nhop_object *nh;
        struct rtentry *rt_orig;
        int error = 0;

        MPASS(rt != NULL);

        nh = rnd_add->rnd_nhop;

        RIB_WLOCK(rnh);

        rt_orig = lookup_prefix_rt(rnh, rt, &rnd_orig);

        if (rt_orig == NULL) {
                if (op_flags & RTM_F_CREATE)
                        error = add_route(rnh, rt, rnd_add, rc);
                else
                        error = ESRCH; /* no entry but creation was not required */
                RIB_WUNLOCK(rnh);
                if (error != 0)
                        goto out;
                return (0);
        }

        if (op_flags & RTM_F_EXCL) {
                /* We have existing route in the RIB but not allowed to replace. */
                RIB_WUNLOCK(rnh);
                error = EEXIST;
                goto out;
        }

        /* Now either append or replace */
        if (op_flags & RTM_F_REPLACE) {
                if (nhop_get_prio(rnd_orig.rnd_nhop) == NH_PRIORITY_HIGH) {
                        /* Old path is "better" (e.g. has PINNED flag set) */
                        RIB_WUNLOCK(rnh);
                        error = EEXIST;
                        goto out;
                }
                change_route(rnh, rt_orig, rnd_add, rc);
                RIB_WUNLOCK(rnh);
                nh = rc->rc_nh_old;
                goto out;
        }

        RIB_WUNLOCK(rnh);

        if ((op_flags & RTM_F_APPEND) && rib_can_multipath(rnh) &&
            nhop_can_multipath(rnd_add->rnd_nhop) &&
            nhop_can_multipath(rnd_orig.rnd_nhop)) {

                for (int i = 0; i < RIB_MAX_RETRIES; i++) {
                        error = add_route_flags_mpath(rnh, rt_orig, rnd_add, &rnd_orig,
                            op_flags, rc);
                        if (error != EAGAIN)
                                break;
                        RTSTAT_INC(rts_add_retry);
                }

                /*
                 *  Original nhop reference is unused in any case.
                 */
                nhop_free_any(rnd_add->rnd_nhop);
                if (op_flags & RTM_F_CREATE) {
                        if (error != 0 || rc->rc_cmd != RTM_ADD)
                                rt_free_immediate(rt);
                }
                return (error);
        }
        /* Out of options - free state and return error */
        error = EEXIST;
out:
        if (op_flags & RTM_F_CREATE)
                rt_free_immediate(rt);
        nhop_free_any(nh);

        return (error);
}

static int
add_route_flags_mpath(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd_add, struct route_nhop_data *rnd_orig,
    int op_flags, struct rib_cmd_info *rc)
{
        RIB_RLOCK_TRACKER;
        struct route_nhop_data rnd_new;
        int error = 0;

        if (!NH_IS_NHGRP(rnd_add->rnd_nhop))
                error = nhgrp_get_addition_group(rnh, rnd_orig, rnd_add, &rnd_new);
        else
                error = nhgrp_get_merge_group(rnh, rnd_orig, rnd_add, &rnd_new);
        if (error != 0) {
                if (error == EAGAIN) {
                        /*
                         * Group creation failed, most probably because
                         * @rnd_orig data got scheduled for deletion.
                         * Refresh @rnd_orig data and retry.
                         */
                        RIB_RLOCK(rnh);
                        lookup_prefix_rt(rnh, rt, rnd_orig);
                        RIB_RUNLOCK(rnh);
                        if (rnd_orig == NULL && !(op_flags & RTM_F_CREATE)) {
                                /* In this iteration route doesn't exist */
                                error = ENOENT;
                        }
                }
                return (error);
        }

        return (change_route_conditional(rnh, rt, rnd_orig, &rnd_new, rc));
}

/*
 * Removes route defined by @info from the kernel table specified by @fibnum and
 * sa_family in @info->rti_info[RTAX_DST].
 *
 * Returns 0 on success and fills in operation metadata into @rc.
 */
int
rib_del_route(uint32_t fibnum, struct rt_addrinfo *info, struct rib_cmd_info *rc)
{
        struct rib_head *rnh;
        struct sockaddr *dst, *netmask;
        struct sockaddr_storage mdst;
        int error;

        NET_EPOCH_ASSERT();

        rnh = get_rnh(fibnum, info);
        if (rnh == NULL)
                return (EAFNOSUPPORT);

        bzero(rc, sizeof(struct rib_cmd_info));
        rc->rc_cmd = RTM_DELETE;

        dst = info->rti_info[RTAX_DST];
        netmask = info->rti_info[RTAX_NETMASK];

        if (netmask != NULL) {
                /* Ensure @dst is always properly masked */
                if (dst->sa_len > sizeof(mdst)) {
                        FIB_RH_LOG(LOG_DEBUG, rnh, "error: dst->sa_len too large");
                        return (EINVAL);
                }
                rt_maskedcopy(dst, (struct sockaddr *)&mdst, netmask);
                dst = (struct sockaddr *)&mdst;
        }

        rib_filter_f_t *filter_func = NULL;
        void *filter_arg = NULL;
        struct gw_filter_data gwd = { .gw = info->rti_info[RTAX_GATEWAY] };

        if (info->rti_filter != NULL) {
                filter_func = info->rti_filter;
                filter_arg = info->rti_filterdata;
        } else if (gwd.gw != NULL) {
                filter_func = match_gw_one;
                filter_arg = &gwd;
        }

        int prio = get_prio_from_info(info);

        RIB_WLOCK(rnh);
        struct route_nhop_data rnd;
        struct rtentry *rt = lookup_prefix_bysa(rnh, dst, netmask, &rnd);
        if (rt != NULL) {
                error = rt_delete_conditional(rnh, rt, prio, filter_func,
                    filter_arg, rc);
        } else
                error = ESRCH;
        RIB_WUNLOCK(rnh);

        if (error != 0)
                return (error);

        rib_notify(rnh, RIB_NOTIFY_DELAYED, rc);

        if (rc->rc_cmd == RTM_DELETE)
                rt_free(rc->rc_rt);
        else {
                /*
                 * Deleting 1 path may result in RTM_CHANGE to
                 * a different mpath group/nhop.
                 * Free old mpath group.
                 */
                nhop_free_any(rc->rc_nh_old);
        }

        return (0);
}

/*
 * Conditionally unlinks rtentry paths from @rnh matching @cb.
 * Returns 0 on success with operation result stored in @rc.
 * On error, returns:
 * ESRCH - if prefix was not found or filter function failed to match
 * EADDRINUSE - if trying to delete higher priority route.
 */
static int
rt_delete_conditional(struct rib_head *rnh, struct rtentry *rt,
    int prio, rib_filter_f_t *cb, void *cbdata, struct rib_cmd_info *rc)
{
        struct nhop_object *nh = rt->rt_nhop;

        if (NH_IS_NHGRP(nh)) {
                struct nhgrp_object *nhg = (struct nhgrp_object *)nh;
                struct route_nhop_data rnd;
                int error;

                if (cb == NULL)
                        return (ESRCH);
                error = nhgrp_get_filtered_group(rnh, rt, nhg, cb, cbdata, &rnd);
                if (error == 0) {
                        if (rnd.rnd_nhgrp == nhg) {
                                /* No match, unreference new group and return. */
                                nhop_free_any(rnd.rnd_nhop);
                                return (ESRCH);
                        }
                        error = change_route(rnh, rt, &rnd, rc);
                }
                return (error);
        }
        if (cb != NULL && !cb(rt, nh, cbdata))
                return (ESRCH);

        if (prio < nhop_get_prio(nh))
                return (EADDRINUSE);

        return (delete_route(rnh, rt, rc));
}

int
rib_change_route(uint32_t fibnum, struct rt_addrinfo *info,
    struct rib_cmd_info *rc)
{
        RIB_RLOCK_TRACKER;
        struct route_nhop_data rnd_orig;
        struct rib_head *rnh;
        struct rtentry *rt;
        int error;

        NET_EPOCH_ASSERT();

        rnh = get_rnh(fibnum, info);
        if (rnh == NULL)
                return (EAFNOSUPPORT);

        bzero(rc, sizeof(struct rib_cmd_info));
        rc->rc_cmd = RTM_CHANGE;

        /* Check if updated gateway exists */
        if ((info->rti_flags & RTF_GATEWAY) &&
            (info->rti_info[RTAX_GATEWAY] == NULL)) {

                /*
                 * route(8) adds RTF_GATEWAY flag if -interface is not set.
                 * Remove RTF_GATEWAY to enforce consistency and maintain
                 * compatibility..
                 */
                info->rti_flags &= ~RTF_GATEWAY;
        }

        /*
         * route change is done in multiple steps, with dropping and
         * reacquiring lock. In the situations with multiple processes
         * changes the same route in can lead to the case when route
         * is changed between the steps. Address it by retrying the operation
         * multiple times before failing.
         */

        RIB_RLOCK(rnh);
        rt = (struct rtentry *)rnh->rnh_lookup(info->rti_info[RTAX_DST],
            info->rti_info[RTAX_NETMASK], &rnh->head);

        if (rt == NULL) {
                RIB_RUNLOCK(rnh);
                return (ESRCH);
        }

        rnd_orig.rnd_nhop = rt->rt_nhop;
        rnd_orig.rnd_weight = rt->rt_weight;

        RIB_RUNLOCK(rnh);

        for (int i = 0; i < RIB_MAX_RETRIES; i++) {
                error = change_route_byinfo(rnh, rt, info, &rnd_orig, rc);
                if (error != EAGAIN)
                        break;
        }

        return (error);
}

static int
change_nhop(struct rib_head *rnh, struct rt_addrinfo *info,
    struct nhop_object *nh_orig, struct nhop_object **nh_new)
{
        int error;

        /*
         * New gateway could require new ifaddr, ifp;
         * flags may also be different; ifp may be specified
         * by ll sockaddr when protocol address is ambiguous
         */
        if (((nh_orig->nh_flags & NHF_GATEWAY) &&
            info->rti_info[RTAX_GATEWAY] != NULL) ||
            info->rti_info[RTAX_IFP] != NULL ||
            (info->rti_info[RTAX_IFA] != NULL &&
             !sa_equal(info->rti_info[RTAX_IFA], nh_orig->nh_ifa->ifa_addr))) {
                error = rt_getifa_fib(info, rnh->rib_fibnum);

                if (error != 0) {
                        info->rti_ifa = NULL;
                        return (error);
                }
        }

        error = nhop_create_from_nhop(rnh, nh_orig, info, nh_new);
        info->rti_ifa = NULL;

        return (error);
}

static int
change_mpath_route(struct rib_head *rnh, struct rtentry *rt,
    struct rt_addrinfo *info, struct route_nhop_data *rnd_orig,
    struct rib_cmd_info *rc)
{
        int error = 0, found_idx = 0;
        struct nhop_object *nh_orig = NULL, *nh_new;
        struct route_nhop_data rnd_new = {};
        const struct weightened_nhop *wn = NULL;
        struct weightened_nhop *wn_new;
        uint32_t num_nhops;

        wn = nhgrp_get_nhops(rnd_orig->rnd_nhgrp, &num_nhops);
        for (int i = 0; i < num_nhops; i++) {
                if (check_info_match_nhop(info, NULL, wn[i].nh) == 0) {
                        nh_orig = wn[i].nh;
                        found_idx = i;
                        break;
                }
        }

        if (nh_orig == NULL)
                return (ESRCH);

        error = change_nhop(rnh, info, nh_orig, &nh_new);
        if (error != 0)
                return (error);

        wn_new = mallocarray(num_nhops, sizeof(struct weightened_nhop),
            M_TEMP, M_NOWAIT | M_ZERO);
        if (wn_new == NULL) {
                nhop_free(nh_new);
                return (EAGAIN);
        }

        memcpy(wn_new, wn, num_nhops * sizeof(struct weightened_nhop));
        wn_new[found_idx].nh = nh_new;
        wn_new[found_idx].weight = get_info_weight(info, wn[found_idx].weight);

        error = nhgrp_get_group(rnh, wn_new, num_nhops, 0, &rnd_new.rnd_nhgrp);
        nhop_free(nh_new);
        free(wn_new, M_TEMP);

        if (error != 0)
                return (error);

        error = change_route_conditional(rnh, rt, rnd_orig, &rnd_new, rc);

        return (error);
}

static int
change_route_byinfo(struct rib_head *rnh, struct rtentry *rt,
    struct rt_addrinfo *info, struct route_nhop_data *rnd_orig,
    struct rib_cmd_info *rc)
{
        int error = 0;
        struct nhop_object *nh_orig;
        struct route_nhop_data rnd_new;

        nh_orig = rnd_orig->rnd_nhop;
        if (nh_orig == NULL)
                return (ESRCH);

        if (NH_IS_NHGRP(nh_orig))
                return (change_mpath_route(rnh, rt, info, rnd_orig, rc));

        rnd_new.rnd_weight = get_info_weight(info, rnd_orig->rnd_weight);
        error = change_nhop(rnh, info, nh_orig, &rnd_new.rnd_nhop);
        if (error != 0)
                return (error);
        error = change_route_conditional(rnh, rt, rnd_orig, &rnd_new, rc);

        return (error);
}

static void
update_tmproutes_mpath(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd)
{
        const struct weightened_nhop *wn;
        uint32_t i, nhops;

        if (NH_IS_NHGRP(rnd->rnd_nhop)) {
                wn = nhgrp_get_nhops(rnd->rnd_nhgrp, &nhops);

                for (i = 0; i < nhops; i++) {
                        if (nhop_get_expire(wn[i].nh) == 0)
                                continue;

                        tmproutes_update(rnh, rt, wn[i].nh);
                }
        } else if (nhop_get_expire(rnd->rnd_nhop) != 0)
                tmproutes_update(rnh, rt, rnd->rnd_nhop);
}

/*
 * Insert @rt with nhop data from @rnd_new to @rnh.
 * Returns 0 on success and stores operation results in @rc.
 */
static int
add_route(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd, struct rib_cmd_info *rc)
{
        struct radix_node *rn;

        RIB_WLOCK_ASSERT(rnh);

        rt->rt_nhop = rnd->rnd_nhop;
        rt->rt_weight = rnd->rnd_weight;
        rn = rnh->rnh_addaddr(rt_key(rt), rt_mask_const(rt), &rnh->head, rt->rt_nodes);

        if (rn != NULL) {
                update_tmproutes_mpath(rnh, rt, rnd);
                /* Finalize notification */
                rib_bump_gen(rnh);
                rnh->rnh_prefixes++;

                rc->rc_cmd = RTM_ADD;
                rc->rc_rt = rt;
                rc->rc_nh_old = NULL;
                rc->rc_nh_new = rnd->rnd_nhop;
                rc->rc_nh_weight = rnd->rnd_weight;

                rib_notify(rnh, RIB_NOTIFY_IMMEDIATE, rc);
                return (0);
        }

        /* Existing route or memory allocation failure. */
        return (EEXIST);
}

/*
 * Unconditionally deletes @rt from @rnh.
 */
static int
delete_route(struct rib_head *rnh, struct rtentry *rt, struct rib_cmd_info *rc)
{
        RIB_WLOCK_ASSERT(rnh);

        /* Route deletion requested. */
        struct radix_node *rn;

        rn = rnh->rnh_deladdr(rt_key_const(rt), rt_mask_const(rt), &rnh->head);
        if (rn == NULL)
                return (ESRCH);
        rt = RNTORT(rn);
        rt->rte_flags &= ~RTF_UP;

        rib_bump_gen(rnh);
        rnh->rnh_prefixes--;

        rc->rc_cmd = RTM_DELETE;
        rc->rc_rt = rt;
        rc->rc_nh_old = rt->rt_nhop;
        rc->rc_nh_new = NULL;
        rc->rc_nh_weight = rt->rt_weight;

        rib_notify(rnh, RIB_NOTIFY_IMMEDIATE, rc);

        return (0);
}

/*
 * Switch @rt nhop/weigh to the ones specified in @rnd.
 * Returns 0 on success.
 */
int
change_route(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd, struct rib_cmd_info *rc)
{
        struct nhop_object *nh_orig;

        RIB_WLOCK_ASSERT(rnh);

        nh_orig = rt->rt_nhop;

        if (rnd->rnd_nhop == NULL)
                return (delete_route(rnh, rt, rc));

        /* Changing nexthop & weight to a new one */
        rt->rt_nhop = rnd->rnd_nhop;
        rt->rt_weight = rnd->rnd_weight;
        update_tmproutes_mpath(rnh, rt, rnd);

        /* Finalize notification */
        rib_bump_gen(rnh);
        rc->rc_cmd = RTM_CHANGE;
        rc->rc_rt = rt;
        rc->rc_nh_old = nh_orig;
        rc->rc_nh_new = rnd->rnd_nhop;
        rc->rc_nh_weight = rnd->rnd_weight;

        rib_notify(rnh, RIB_NOTIFY_IMMEDIATE, rc);

        return (0);
}

/*
 * Conditionally update route nhop/weight IFF data in @nhd_orig is
 *  consistent with the current route data.
 * Nexthop in @nhd_new is consumed.
 */
int
change_route_conditional(struct rib_head *rnh, struct rtentry *rt,
    struct route_nhop_data *rnd_orig, struct route_nhop_data *rnd_new,
    struct rib_cmd_info *rc)
{
        struct rtentry *rt_new;
        int error = 0;

        IF_DEBUG_LEVEL(LOG_DEBUG2) {
                char buf_old[NHOP_PRINT_BUFSIZE], buf_new[NHOP_PRINT_BUFSIZE];
                nhop_print_buf_any(rnd_orig->rnd_nhop, buf_old, NHOP_PRINT_BUFSIZE);
                nhop_print_buf_any(rnd_new->rnd_nhop, buf_new, NHOP_PRINT_BUFSIZE);
                FIB_LOG(LOG_DEBUG2, rnh->rib_fibnum, rnh->rib_family,
                    "trying change %s -> %s", buf_old, buf_new);
        }
        RIB_WLOCK(rnh);

        struct route_nhop_data rnd;
        rt_new = lookup_prefix_rt(rnh, rt, &rnd);

        if (rt_new == NULL) {
                if (rnd_orig->rnd_nhop == NULL)
                        error = add_route(rnh, rt, rnd_new, rc);
                else {
                        /*
                         * Prefix does not exist, which was not our assumption.
                         * Update @rnd_orig with the new data and return
                         */
                        rnd_orig->rnd_nhop = NULL;
                        rnd_orig->rnd_weight = 0;
                        error = EAGAIN;
                }
        } else {
                /* Prefix exists, try to update */
                if (rnd_orig->rnd_nhop == rt_new->rt_nhop) {
                        /*
                         * Nhop/mpath group hasn't changed. Flip
                         * to the new precalculated one and return
                         */
                        error = change_route(rnh, rt_new, rnd_new, rc);
                } else {
                        /* Update and retry */
                        rnd_orig->rnd_nhop = rt_new->rt_nhop;
                        rnd_orig->rnd_weight = rt_new->rt_weight;
                        error = EAGAIN;
                }
        }

        RIB_WUNLOCK(rnh);

        if (error == 0) {
                rib_notify(rnh, RIB_NOTIFY_DELAYED, rc);

                if (rnd_orig->rnd_nhop != NULL)
                        nhop_free_any(rnd_orig->rnd_nhop);

        } else {
                if (rnd_new->rnd_nhop != NULL)
                        nhop_free_any(rnd_new->rnd_nhop);
        }

        return (error);
}

/*
 * Performs modification of routing table specificed by @action.
 * Table is specified by @fibnum and sa_family in @info->rti_info[RTAX_DST].
 * Needs to be run in network epoch.
 *
 * Returns 0 on success and fills in @rc with action result.
 */
int
rib_action(uint32_t fibnum, int action, struct rt_addrinfo *info,
    struct rib_cmd_info *rc)
{
        int error;

        switch (action) {
        case RTM_ADD:
                error = rib_add_route(fibnum, info, rc);
                break;
        case RTM_DELETE:
                error = rib_del_route(fibnum, info, rc);
                break;
        case RTM_CHANGE:
                error = rib_change_route(fibnum, info, rc);
                break;
        default:
                error = ENOTSUP;
        }

        return (error);
}

struct rt_delinfo
{
        struct rib_head *rnh;
        struct rtentry *head;
        rib_filter_f_t *filter_f;
        void *filter_arg;
        int prio;
        struct rib_cmd_info rc;
};

/*
 * Conditionally unlinks rtenties or paths from radix tree based
 * on the callback data passed in @arg.
 */
static int
rt_checkdelroute(struct radix_node *rn, void *arg)
{
        struct rt_delinfo *di = (struct rt_delinfo *)arg;
        struct rtentry *rt = (struct rtentry *)rn;

        if (rt_delete_conditional(di->rnh, rt, di->prio,
            di->filter_f, di->filter_arg, &di->rc) != 0)
                return (0);

        /*
         * Add deleted rtentries to the list to GC them
         *  after dropping the lock.
         *
         * XXX: Delayed notifications not implemented
         *  for nexthop updates.
         */
        if (di->rc.rc_cmd == RTM_DELETE) {
                /* Add to the list and return */
                rt->rt_chain = di->head;
                di->head = rt;
        } else {
                /*
                 * RTM_CHANGE to a different nexthop or nexthop group.
                 * Free old multipath group.
                 */
                nhop_free_any(di->rc.rc_nh_old);
        }

        return (0);
}

/*
 * Iterates over a routing table specified by @fibnum and @family and
 *  deletes elements marked by @filter_f.
 * @fibnum: rtable id
 * @family: AF_ address family
 * @filter_f: function returning non-zero value for items to delete
 * @arg: data to pass to the @filter_f function
 * @report: true if rtsock notification is needed.
 */
void
rib_walk_del(u_int fibnum, int family, rib_filter_f_t *filter_f, void *filter_arg,
    bool report)
{
        struct rib_head *rnh;
        struct rtentry *rt;
        struct nhop_object *nh;
        struct epoch_tracker et;

        rnh = rt_tables_get_rnh(fibnum, family);
        if (rnh == NULL)
                return;

        struct rt_delinfo di = {
                .rnh = rnh,
                .filter_f = filter_f,
                .filter_arg = filter_arg,
                .prio = NH_PRIORITY_NORMAL,
        };

        NET_EPOCH_ENTER(et);

        RIB_WLOCK(rnh);
        rnh->rnh_walktree(&rnh->head, rt_checkdelroute, &di);
        RIB_WUNLOCK(rnh);

        /* We might have something to reclaim. */
        bzero(&di.rc, sizeof(di.rc));
        di.rc.rc_cmd = RTM_DELETE;
        while (di.head != NULL) {
                rt = di.head;
                di.head = rt->rt_chain;
                rt->rt_chain = NULL;
                nh = rt->rt_nhop;

                di.rc.rc_rt = rt;
                di.rc.rc_nh_old = nh;
                rib_notify(rnh, RIB_NOTIFY_DELAYED, &di.rc);

                if (report) {
                        struct nhgrp_object *nhg;
                        const struct weightened_nhop *wn;
                        uint32_t num_nhops;
                        if (NH_IS_NHGRP(nh)) {
                                nhg = (struct nhgrp_object *)nh;
                                wn = nhgrp_get_nhops(nhg, &num_nhops);
                                for (int i = 0; i < num_nhops; i++)
                                        rt_routemsg(RTM_DELETE, rt, wn[i].nh, fibnum);
                        } else
                                rt_routemsg(RTM_DELETE, rt, nh, fibnum);
                }
                rt_free(rt);
        }

        NET_EPOCH_EXIT(et);
}

static int
rt_delete_unconditional(struct radix_node *rn, void *arg)
{
        struct rtentry *rt = RNTORT(rn);
        struct rib_head *rnh = (struct rib_head *)arg;

        rn = rnh->rnh_deladdr(rt_key(rt), rt_mask(rt), &rnh->head);
        if (RNTORT(rn) == rt)
                rt_free(rt);

        return (0);
}

/*
 * Removes all routes from the routing table without executing notifications.
 * rtentres will be removed after the end of a current epoch.
 */
static void
rib_flush_routes(struct rib_head *rnh)
{
        RIB_WLOCK(rnh);
        rnh->rnh_walktree(&rnh->head, rt_delete_unconditional, rnh);
        RIB_WUNLOCK(rnh);
}

void
rib_flush_routes_family(int family)
{
        struct rib_head *rnh;

        for (uint32_t fibnum = 0; fibnum < rt_numfibs; fibnum++) {
                if ((rnh = rt_tables_get_rnh(fibnum, family)) != NULL)
                        rib_flush_routes(rnh);
        }
}

const char *
rib_print_family(int family)
{
        switch (family) {
        case AF_INET:
                return ("inet");
        case AF_INET6:
                return ("inet6");
        case AF_LINK:
                return ("link");
        }
        return ("unknown");
}