/*-
 * SPDX-License-Identifier: BSD-3-Clause
 *
 * Copyright (c) 1982, 1986, 1988, 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.
 */

#include "opt_bootp.h"
#include "opt_inet.h"
#include "opt_ipstealth.h"
#include "opt_ipsec.h"
#include "opt_rss.h"
#include "opt_sctp.h"

#include <sys/param.h>
#include <sys/systm.h>
#include <sys/hhook.h>
#include <sys/mbuf.h>
#include <sys/malloc.h>
#include <sys/domain.h>
#include <sys/protosw.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/rmlock.h>
#include <sys/rwlock.h>
#include <sys/sdt.h>
#include <sys/syslog.h>
#include <sys/sysctl.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/if_var.h>
#include <net/if_dl.h>
#include <net/if_private.h>
#include <net/pfil.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/netisr.h>
#include <net/rss_config.h>
#include <net/vnet.h>

#include <netinet/in.h>
#include <netinet/in_kdtrace.h>
#include <netinet/in_systm.h>
#include <netinet/in_var.h>
#include <netinet/ip.h>
#include <netinet/in_fib.h>
#include <netinet/in_pcb.h>
#include <netinet/ip_var.h>
#include <netinet/ip_encap.h>
#include <netinet/ip_fw.h>
#include <netinet/ip_icmp.h>
#include <netinet/igmp_var.h>
#include <netinet/ip_options.h>
#include <machine/in_cksum.h>
#include <netinet/ip_carp.h>
#include <netinet/in_rss.h>
#include <netinet/ip_mroute.h>
#ifdef SCTP
#include <netinet/sctp_var.h>
#endif

#include <netipsec/ipsec_support.h>

#include <sys/socketvar.h>

#include <security/mac/mac_framework.h>

#ifdef CTASSERT
CTASSERT(sizeof(struct ip) == 20);
#endif

/* IP reassembly functions are defined in ip_reass.c. */
extern void ipreass_init(void);
extern void ipreass_vnet_init(void);
#ifdef VIMAGE
extern void ipreass_destroy(void);
#endif

VNET_DEFINE(int, rsvp_on);

VNET_DEFINE(int, ipforwarding);
SYSCTL_INT(_net_inet_ip, IPCTL_FORWARDING, forwarding, CTLFLAG_VNET | CTLFLAG_RW,
    &VNET_NAME(ipforwarding), 0,
    "Enable IP forwarding between interfaces");

/*
 * Respond with an ICMP host redirect when we forward a packet out of
 * the same interface on which it was received.  See RFC 792.
 */
VNET_DEFINE(int, ipsendredirects) = 1;
SYSCTL_INT(_net_inet_ip, IPCTL_SENDREDIRECTS, redirect, CTLFLAG_VNET | CTLFLAG_RW,
    &VNET_NAME(ipsendredirects), 0,
    "Enable sending IP redirects");

VNET_DEFINE_STATIC(bool, ip_strong_es) = false;
#define V_ip_strong_es  VNET(ip_strong_es)
SYSCTL_BOOL(_net_inet_ip, OID_AUTO, rfc1122_strong_es,
    CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_strong_es), false,
    "Packet's IP destination address must match address on arrival interface");

VNET_DEFINE_STATIC(bool, ip_sav) = true;
#define V_ip_sav        VNET(ip_sav)
SYSCTL_BOOL(_net_inet_ip, OID_AUTO, source_address_validation,
    CTLFLAG_VNET | CTLFLAG_RW, &VNET_NAME(ip_sav), true,
    "Drop incoming packets with source address that is a local address");

/* Packet filter hooks */
VNET_DEFINE(pfil_head_t, inet_pfil_head);
VNET_DEFINE(pfil_head_t, inet_local_pfil_head);

static struct netisr_handler ip_nh = {
        .nh_name = "ip",
        .nh_handler = ip_input,
        .nh_proto = NETISR_IP,
#ifdef  RSS
        .nh_m2cpuid = rss_soft_m2cpuid_v4,
        .nh_policy = NETISR_POLICY_CPU,
        .nh_dispatch = NETISR_DISPATCH_HYBRID,
#else
        .nh_policy = NETISR_POLICY_FLOW,
#endif
};

#ifdef  RSS
/*
 * Directly dispatched frames are currently assumed
 * to have a flowid already calculated.
 *
 * It should likely have something that assert it
 * actually has valid flow details.
 */
static struct netisr_handler ip_direct_nh = {
        .nh_name = "ip_direct",
        .nh_handler = ip_direct_input,
        .nh_proto = NETISR_IP_DIRECT,
        .nh_m2cpuid = rss_soft_m2cpuid_v4,
        .nh_policy = NETISR_POLICY_CPU,
        .nh_dispatch = NETISR_DISPATCH_HYBRID,
};
#endif

ipproto_input_t         *ip_protox[IPPROTO_MAX] = {
                            [0 ... IPPROTO_MAX - 1] = rip_input };
ipproto_ctlinput_t      *ip_ctlprotox[IPPROTO_MAX] = {
                            [0 ... IPPROTO_MAX - 1] = rip_ctlinput };

VNET_DEFINE(struct in_ifaddrhead, in_ifaddrhead);  /* first inet address */
VNET_DEFINE(struct in_ifaddrhashhead *, in_ifaddrhashtbl); /* inet addr hash table  */
VNET_DEFINE(u_long, in_ifaddrhmask);            /* mask for hash table */

/* Make sure it is safe to use hashinit(9) on CK_LIST. */
CTASSERT(sizeof(struct in_ifaddrhashhead) == sizeof(LIST_HEAD(, in_addr)));

#ifdef IPCTL_DEFMTU
SYSCTL_INT(_net_inet_ip, IPCTL_DEFMTU, mtu, CTLFLAG_RW,
    &ip_mtu, 0, "Default MTU");
#endif

#ifdef IPSTEALTH
VNET_DEFINE(int, ipstealth);
SYSCTL_INT(_net_inet_ip, OID_AUTO, stealth, CTLFLAG_VNET | CTLFLAG_RW,
    &VNET_NAME(ipstealth), 0,
    "IP stealth mode, no TTL decrementation on forwarding");
#endif

/*
 * IP statistics are stored in the "array" of counter(9)s.
 */
VNET_PCPUSTAT_DEFINE(struct ipstat, ipstat);
VNET_PCPUSTAT_SYSINIT(ipstat);
SYSCTL_VNET_PCPUSTAT(_net_inet_ip, IPCTL_STATS, stats, struct ipstat, ipstat,
    "IP statistics (struct ipstat, netinet/ip_var.h)");

#ifdef VIMAGE
VNET_PCPUSTAT_SYSUNINIT(ipstat);
#endif /* VIMAGE */

/*
 * Kernel module interface for updating ipstat.  The argument is an index
 * into ipstat treated as an array.
 */
void
kmod_ipstat_inc(int statnum)
{

        counter_u64_add(VNET(ipstat)[statnum], 1);
}

void
kmod_ipstat_dec(int statnum)
{

        counter_u64_add(VNET(ipstat)[statnum], -1);
}

static int
sysctl_netinet_intr_queue_maxlen(SYSCTL_HANDLER_ARGS)
{
        int error, qlimit;

        netisr_getqlimit(&ip_nh, &qlimit);
        error = sysctl_handle_int(oidp, &qlimit, 0, req);
        if (error || !req->newptr)
                return (error);
        if (qlimit < 1)
                return (EINVAL);
        return (netisr_setqlimit(&ip_nh, qlimit));
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQMAXLEN, intr_queue_maxlen,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, 0, 0,
    sysctl_netinet_intr_queue_maxlen, "I",
    "Maximum size of the IP input queue");

static int
sysctl_netinet_intr_queue_drops(SYSCTL_HANDLER_ARGS)
{
        u_int64_t qdrops_long;
        int error, qdrops;

        netisr_getqdrops(&ip_nh, &qdrops_long);
        qdrops = qdrops_long;
        error = sysctl_handle_int(oidp, &qdrops, 0, req);
        if (error || !req->newptr)
                return (error);
        if (qdrops != 0)
                return (EINVAL);
        netisr_clearqdrops(&ip_nh);
        return (0);
}

SYSCTL_PROC(_net_inet_ip, IPCTL_INTRQDROPS, intr_queue_drops,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE,
    0, 0, sysctl_netinet_intr_queue_drops, "I",
    "Number of packets dropped from the IP input queue");

#ifdef  RSS
static int
sysctl_netinet_intr_direct_queue_maxlen(SYSCTL_HANDLER_ARGS)
{
        int error, qlimit;

        netisr_getqlimit(&ip_direct_nh, &qlimit);
        error = sysctl_handle_int(oidp, &qlimit, 0, req);
        if (error || !req->newptr)
                return (error);
        if (qlimit < 1)
                return (EINVAL);
        return (netisr_setqlimit(&ip_direct_nh, qlimit));
}
SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQMAXLEN, intr_direct_queue_maxlen,
    CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
    0, 0, sysctl_netinet_intr_direct_queue_maxlen,
    "I", "Maximum size of the IP direct input queue");

static int
sysctl_netinet_intr_direct_queue_drops(SYSCTL_HANDLER_ARGS)
{
        u_int64_t qdrops_long;
        int error, qdrops;

        netisr_getqdrops(&ip_direct_nh, &qdrops_long);
        qdrops = qdrops_long;
        error = sysctl_handle_int(oidp, &qdrops, 0, req);
        if (error || !req->newptr)
                return (error);
        if (qdrops != 0)
                return (EINVAL);
        netisr_clearqdrops(&ip_direct_nh);
        return (0);
}

SYSCTL_PROC(_net_inet_ip, IPCTL_INTRDQDROPS, intr_direct_queue_drops,
    CTLTYPE_INT | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
    sysctl_netinet_intr_direct_queue_drops, "I",
    "Number of packets dropped from the IP direct input queue");
#endif  /* RSS */

/*
 * IP initialization: fill in IP protocol switch table.
 * All protocols not implemented in kernel go to raw IP protocol handler.
 */
static void
ip_vnet_init(void *arg __unused)
{
        struct pfil_head_args args;

        CK_STAILQ_INIT(&V_in_ifaddrhead);
        V_in_ifaddrhashtbl = hashinit(INADDR_NHASH, M_IFADDR, &V_in_ifaddrhmask);

        /* Initialize IP reassembly queue. */
        ipreass_vnet_init();

        /* Initialize packet filter hooks. */
        args.pa_version = PFIL_VERSION;
        args.pa_flags = PFIL_IN | PFIL_OUT;
        args.pa_type = PFIL_TYPE_IP4;
        args.pa_headname = PFIL_INET_NAME;
        V_inet_pfil_head = pfil_head_register(&args);

        args.pa_flags = PFIL_OUT;
        args.pa_headname = PFIL_INET_LOCAL_NAME;
        V_inet_local_pfil_head = pfil_head_register(&args);

        if (hhook_head_register(HHOOK_TYPE_IPSEC_IN, AF_INET,
            &V_ipsec_hhh_in[HHOOK_IPSEC_INET],
            HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
                printf("%s: WARNING: unable to register input helper hook\n",
                    __func__);
        if (hhook_head_register(HHOOK_TYPE_IPSEC_OUT, AF_INET,
            &V_ipsec_hhh_out[HHOOK_IPSEC_INET],
            HHOOK_WAITOK | HHOOK_HEADISINVNET) != 0)
                printf("%s: WARNING: unable to register output helper hook\n",
                    __func__);

#ifdef VIMAGE
        netisr_register_vnet(&ip_nh);
#ifdef  RSS
        netisr_register_vnet(&ip_direct_nh);
#endif
#endif
}
VNET_SYSINIT(ip_vnet_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_FOURTH,
    ip_vnet_init, NULL);

static void
ip_init(const void *unused __unused)
{
        struct ifnet *ifp;

        ipreass_init();

        /*
         * Register statically compiled protocols, that are unlikely to
         * ever become dynamic.
         */
        IPPROTO_REGISTER(IPPROTO_ICMP, icmp_input, NULL);
        IPPROTO_REGISTER(IPPROTO_IGMP, igmp_input, NULL);
        IPPROTO_REGISTER(IPPROTO_RSVP, rsvp_input, NULL);
        IPPROTO_REGISTER(IPPROTO_IPV4, encap4_input, NULL);
        IPPROTO_REGISTER(IPPROTO_MOBILE, encap4_input, NULL);
        IPPROTO_REGISTER(IPPROTO_ETHERIP, encap4_input, NULL);
        IPPROTO_REGISTER(IPPROTO_GRE, encap4_input, NULL);
        IPPROTO_REGISTER(IPPROTO_IPV6, encap4_input, NULL);
        IPPROTO_REGISTER(IPPROTO_PIM, encap4_input, NULL);
#ifdef SCTP     /* XXX: has a loadable & static version */
        IPPROTO_REGISTER(IPPROTO_SCTP, sctp_input, sctp_ctlinput);
#endif

        netisr_register(&ip_nh);
#ifdef  RSS
        netisr_register(&ip_direct_nh);
#endif
        /*
         * XXXGL: we use SYSINIT() here, but go over V_ifnet.  It was the same
         * way before dom_ifattach removal.  This worked because when any
         * non-default vnet is created, there are no interfaces inside.
         * Eventually this needs to be fixed.
         */
        CK_STAILQ_FOREACH(ifp, &V_ifnet, if_link)
                in_ifattach(NULL, ifp);
}
SYSINIT(ip_init, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_init, NULL);

#ifdef VIMAGE
static void
ip_destroy(void *unused __unused)
{
        int error;

#ifdef  RSS
        netisr_unregister_vnet(&ip_direct_nh);
#endif
        netisr_unregister_vnet(&ip_nh);

        pfil_head_unregister(V_inet_pfil_head);
        error = hhook_head_deregister(V_ipsec_hhh_in[HHOOK_IPSEC_INET]);
        if (error != 0) {
                printf("%s: WARNING: unable to deregister input helper hook "
                    "type HHOOK_TYPE_IPSEC_IN, id HHOOK_IPSEC_INET: "
                    "error %d returned\n", __func__, error);
        }
        error = hhook_head_deregister(V_ipsec_hhh_out[HHOOK_IPSEC_INET]);
        if (error != 0) {
                printf("%s: WARNING: unable to deregister output helper hook "
                    "type HHOOK_TYPE_IPSEC_OUT, id HHOOK_IPSEC_INET: "
                    "error %d returned\n", __func__, error);
        }

        /* Remove the IPv4 addresses from all interfaces. */
        in_ifscrub_all();

        /* Make sure the IPv4 routes are gone as well. */
        rib_flush_routes_family(AF_INET);

        /* Destroy IP reassembly queue. */
        ipreass_destroy();

        /* Cleanup in_ifaddr hash table; should be empty. */
        hashdestroy(V_in_ifaddrhashtbl, M_IFADDR, V_in_ifaddrhmask);
}

VNET_SYSUNINIT(ip, SI_SUB_PROTO_DOMAIN, SI_ORDER_THIRD, ip_destroy, NULL);
#endif

#ifdef  RSS
/*
 * IP direct input routine.
 *
 * This is called when reinjecting completed fragments where
 * all of the previous checking and book-keeping has been done.
 */
void
ip_direct_input(struct mbuf *m)
{
        struct ip *ip;
        int hlen;

        ip = mtod(m, struct ip *);
        hlen = ip->ip_hl << 2;

#if defined(IPSEC) || defined(IPSEC_SUPPORT)
        if (IPSEC_ENABLED(ipv4)) {
                if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
                        return;
        }
#endif /* IPSEC */
        IPSTAT_INC(ips_delivered);
        ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
}
#endif

/*
 * Ip input routine.  Checksum and byte swap header.  If fragmented
 * try to reassemble.  Process options.  Pass to next level.
 */
void
ip_input(struct mbuf *m)
{
        struct ip *ip = NULL;
        struct in_ifaddr *ia = NULL;
        struct ifaddr *ifa;
        struct ifnet *ifp;
        int hlen = 0;
        uint16_t sum, ip_len;
        int dchg = 0;                           /* dest changed after fw */
        struct in_addr odst;                    /* original dst address */
        bool strong_es;

        M_ASSERTPKTHDR(m);
        NET_EPOCH_ASSERT();

        if (m->m_flags & M_FASTFWD_OURS) {
                m->m_flags &= ~M_FASTFWD_OURS;
                /* Set up some basics that will be used later. */
                ip = mtod(m, struct ip *);
                hlen = ip->ip_hl << 2;
                ip_len = ntohs(ip->ip_len);
                goto ours;
        }

        IPSTAT_INC(ips_total);

        if (__predict_false(m->m_pkthdr.len < sizeof(struct ip)))
                goto tooshort;

        if (m->m_len < sizeof(struct ip)) {
                m = m_pullup(m, sizeof(struct ip));
                if (__predict_false(m == NULL)) {
                        IPSTAT_INC(ips_toosmall);
                        return;
                }
        }
        ip = mtod(m, struct ip *);

        if (__predict_false(ip->ip_v != IPVERSION)) {
                IPSTAT_INC(ips_badvers);
                goto bad;
        }

        hlen = ip->ip_hl << 2;
        if (__predict_false(hlen < sizeof(struct ip))) {        /* minimum header length */
                IPSTAT_INC(ips_badhlen);
                goto bad;
        }
        if (hlen > m->m_len) {
                m = m_pullup(m, hlen);
                if (__predict_false(m == NULL)) {
                        IPSTAT_INC(ips_badhlen);
                        return;
                }
                ip = mtod(m, struct ip *);
        }

        IP_PROBE(receive, NULL, NULL, ip, m->m_pkthdr.rcvif, ip, NULL);

        /* IN_LOOPBACK must not appear on the wire - RFC1122 */
        ifp = m->m_pkthdr.rcvif;
        if (IN_LOOPBACK(ntohl(ip->ip_dst.s_addr)) ||
            IN_LOOPBACK(ntohl(ip->ip_src.s_addr))) {
                if ((ifp->if_flags & IFF_LOOPBACK) == 0) {
                        IPSTAT_INC(ips_badaddr);
                        goto bad;
                }
        }

        if (m->m_pkthdr.csum_flags & CSUM_IP_CHECKED) {
                sum = !(m->m_pkthdr.csum_flags & CSUM_IP_VALID);
        } else if (m->m_pkthdr.csum_flags & CSUM_IP) {
                /*
                 * Packet from local host that offloaded checksum computation.
                 * Checksum not required since the packet wasn't on the wire.
                 */
                sum = 0;
        } else {
                if (hlen == sizeof(struct ip)) {
                        sum = in_cksum_hdr(ip);
                } else {
                        sum = in_cksum(m, hlen);
                }
        }
        if (__predict_false(sum)) {
                IPSTAT_INC(ips_badsum);
                goto bad;
        }

        ip_len = ntohs(ip->ip_len);
        if (__predict_false(ip_len < hlen)) {
                IPSTAT_INC(ips_badlen);
                goto bad;
        }

        /*
         * Check that the amount of data in the buffers
         * is as at least much as the IP header would have us expect.
         * Trim mbufs if longer than we expect.
         * Drop packet if shorter than we expect.
         */
        if (__predict_false(m->m_pkthdr.len < ip_len)) {
tooshort:
                IPSTAT_INC(ips_tooshort);
                goto bad;
        }
        if (m->m_pkthdr.len > ip_len) {
                if (m->m_len == m->m_pkthdr.len) {
                        m->m_len = ip_len;
                        m->m_pkthdr.len = ip_len;
                } else
                        m_adj(m, ip_len - m->m_pkthdr.len);
        }

        /*
         * Try to forward the packet, but if we fail continue.
         * ip_tryforward() may generate redirects these days.
         * XXX the logic below falling through to normal processing
         * if redirects are required should be revisited as well.
         * ip_tryforward() does inbound and outbound packet firewall
         * processing. If firewall has decided that destination becomes
         * our local address, it sets M_FASTFWD_OURS flag. In this
         * case skip another inbound firewall processing and update
         * ip pointer.
         */
        if (V_ipforwarding != 0
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
            && (!IPSEC_ENABLED(ipv4) ||
            IPSEC_CAPS(ipv4, m, IPSEC_CAP_OPERABLE) == 0)
#endif
            ) {
                /*
                 * ip_dooptions() was run so we can ignore the source route (or
                 * any IP options case) case for redirects in ip_tryforward().
                 */
                if ((m = ip_tryforward(m)) == NULL)
                        return;
                if (m->m_flags & M_FASTFWD_OURS) {
                        m->m_flags &= ~M_FASTFWD_OURS;
                        ip = mtod(m, struct ip *);
                        goto ours;
                }
        }

#if defined(IPSEC) || defined(IPSEC_SUPPORT)
        /*
         * Bypass packet filtering for packets previously handled by IPsec.
         */
        if (IPSEC_ENABLED(ipv4) &&
            IPSEC_CAPS(ipv4, m, IPSEC_CAP_BYPASS_FILTER) != 0)
                        goto passin;
#endif

        /*
         * Run through list of hooks for input packets.
         *
         * NB: Beware of the destination address changing (e.g.
         *     by NAT rewriting).  When this happens, tell
         *     ip_forward to do the right thing.
         */

        /* Jump over all PFIL processing if hooks are not active. */
        if (!PFIL_HOOKED_IN(V_inet_pfil_head))
                goto passin;

        odst = ip->ip_dst;
        if (pfil_mbuf_in(V_inet_pfil_head, &m, ifp, NULL) !=
            PFIL_PASS)
                return;

        ip = mtod(m, struct ip *);
        dchg = (odst.s_addr != ip->ip_dst.s_addr);

        if (m->m_flags & M_FASTFWD_OURS) {
                m->m_flags &= ~M_FASTFWD_OURS;
                goto ours;
        }
        if (m->m_flags & M_IP_NEXTHOP) {
                if (m_tag_find(m, PACKET_TAG_IPFORWARD, NULL) != NULL) {
                        /*
                         * Directly ship the packet on.  This allows
                         * forwarding packets originally destined to us
                         * to some other directly connected host.
                         */
                        ip_forward(m, 1);
                        return;
                }
        }
passin:
        /*
         * The unspecified address can appear only as a src address - RFC1122.
         *
         * The check is deferred to here to give firewalls a chance to block
         * (and log) such packets.  ip_tryforward() will not process such
         * packets.
         */
        if (__predict_false(ntohl(ip->ip_dst.s_addr) == INADDR_ANY)) {
                IPSTAT_INC(ips_badaddr);
                goto bad;
        }

        /*
         * Process options and, if not destined for us,
         * ship it on.  ip_dooptions returns 1 when an
         * error was detected (causing an icmp message
         * to be sent and the original packet to be freed).
         */
        if (hlen > sizeof (struct ip) && ip_dooptions(m, 0))
                return;

        /* greedy RSVP, snatches any PATH packet of the RSVP protocol and no
         * matter if it is destined to another node, or whether it is
         * a multicast one, RSVP wants it! and prevents it from being forwarded
         * anywhere else. Also checks if the rsvp daemon is running before
         * grabbing the packet.
         */
        if (ip->ip_p == IPPROTO_RSVP && V_rsvp_on)
                goto ours;

        /*
         * Check our list of addresses, to see if the packet is for us.
         * If we don't have any addresses, assume any unicast packet
         * we receive might be for us (and let the upper layers deal
         * with it).
         */
        if (CK_STAILQ_EMPTY(&V_in_ifaddrhead) &&
            (m->m_flags & (M_MCAST|M_BCAST)) == 0)
                goto ours;

        /*
         * Enable a consistency check between the destination address
         * and the arrival interface for a unicast packet (the RFC 1122
         * strong ES model) with a list of additional predicates:
         * - if IP forwarding is disabled
         * - the packet is not locally generated
         * - the packet is not subject to 'ipfw fwd'
         * - Interface is not running CARP. If the packet got here, we already
         *   checked it with carp_iamatch() and carp_forus().
         */
        strong_es = V_ip_strong_es && (V_ipforwarding == 0) &&
            ((ifp->if_flags & IFF_LOOPBACK) == 0) &&
            ifp->if_carp == NULL && (dchg == 0);

        /*
         * Check for exact addresses in the hash bucket.
         */
        CK_LIST_FOREACH(ia, INADDR_HASH(ip->ip_dst.s_addr), ia_hash) {
                if (IA_SIN(ia)->sin_addr.s_addr != ip->ip_dst.s_addr)
                        continue;

                /*
                 * net.inet.ip.rfc1122_strong_es: the address matches, verify
                 * that the packet arrived via the correct interface.
                 */
                if (__predict_false(strong_es && ia->ia_ifp != ifp)) {
                        IPSTAT_INC(ips_badaddr);
                        goto bad;
                }

                /*
                 * net.inet.ip.source_address_validation: drop incoming
                 * packets that pretend to be ours.
                 */
                if (V_ip_sav && !(ifp->if_flags & IFF_LOOPBACK) &&
                    __predict_false(in_localip_fib(ip->ip_src, ifp->if_fib))) {
                        IPSTAT_INC(ips_badaddr);
                        goto bad;
                }

                counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
                counter_u64_add(ia->ia_ifa.ifa_ibytes, m->m_pkthdr.len);
                goto ours;
        }

        /*
         * Check for broadcast addresses.
         *
         * Only accept broadcast packets that arrive via the matching
         * interface.  Reception of forwarded directed broadcasts would
         * be handled via ip_forward() and ether_output() with the loopback
         * into the stack for SIMPLEX interfaces handled by ether_output().
         */
        if (ifp->if_flags & IFF_BROADCAST) {
                CK_STAILQ_FOREACH(ifa, &ifp->if_addrhead, ifa_link) {
                        if (ifa->ifa_addr->sa_family != AF_INET)
                                continue;
                        ia = ifatoia(ifa);
                        if (satosin(&ia->ia_broadaddr)->sin_addr.s_addr ==
                            ip->ip_dst.s_addr) {
                                counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
                                counter_u64_add(ia->ia_ifa.ifa_ibytes,
                                    m->m_pkthdr.len);
                                goto ours;
                        }
#ifdef BOOTP_COMPAT
                        if (IA_SIN(ia)->sin_addr.s_addr == INADDR_ANY) {
                                counter_u64_add(ia->ia_ifa.ifa_ipackets, 1);
                                counter_u64_add(ia->ia_ifa.ifa_ibytes,
                                    m->m_pkthdr.len);
                                goto ours;
                        }
#endif
                }
                ia = NULL;
        }
        if (IN_MULTICAST(ntohl(ip->ip_dst.s_addr))) {
                /*
                 * RFC 3927 2.7: Do not forward multicast packets from
                 * IN_LINKLOCAL.
                 */
                if (V_ip_mrouting_enabled &&
                    !IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
                        /*
                         * If we are acting as a multicast router, all
                         * incoming multicast packets are passed to the
                         * kernel-level multicast forwarding function.
                         * The packet is returned (relatively) intact; if
                         * ip_mforward() returns a non-zero value, the packet
                         * must be discarded, else it may be accepted below.
                         */
                        if (ip_mforward && ip_mforward(ip, ifp, m, 0) != 0) {
                                IPSTAT_INC(ips_cantforward);
                                m_freem(m);
                                return;
                        }

                        /*
                         * The process-level routing daemon needs to receive
                         * all multicast IGMP packets, whether or not this
                         * host belongs to their destination groups.
                         */
                        if (ip->ip_p == IPPROTO_IGMP) {
                                goto ours;
                        }
                        IPSTAT_INC(ips_forward);
                }
                /*
                 * Assume the packet is for us, to avoid prematurely taking
                 * a lock on the in_multi hash. Protocols must perform
                 * their own filtering and update statistics accordingly.
                 */
                goto ours;
        }
        if (in_broadcast(ip->ip_dst))
                goto ours;
        /* RFC 3927 2.7: Do not forward packets to or from IN_LINKLOCAL. */
        if (IN_LINKLOCAL(ntohl(ip->ip_dst.s_addr)) ||
            IN_LINKLOCAL(ntohl(ip->ip_src.s_addr))) {
                IPSTAT_INC(ips_cantforward);
                m_freem(m);
                return;
        }

        /*
         * Not for us; forward if possible and desirable.
         */
        if (V_ipforwarding == 0) {
                IPSTAT_INC(ips_cantforward);
                m_freem(m);
        } else {
                ip_forward(m, dchg);
        }
        return;

ours:
#ifdef IPSTEALTH
        /*
         * IPSTEALTH: Process non-routing options only
         * if the packet is destined for us.
         */
        if (V_ipstealth && hlen > sizeof (struct ip) && ip_dooptions(m, 1))
                return;
#endif /* IPSTEALTH */

        /*
         * We are going to ship the packet to the local protocol stack. Call the
         * filter again for this 'output' action, allowing redirect-like rules
         * to adjust the source address.
         */
        if (PFIL_HOOKED_OUT(V_inet_local_pfil_head)) {
                if (pfil_mbuf_out(V_inet_local_pfil_head, &m, V_loif, NULL) !=
                    PFIL_PASS)
                        return;
                ip = mtod(m, struct ip *);
        }

        /*
         * Attempt reassembly; if it succeeds, proceed.
         * ip_reass() will return a different mbuf.
         */
        if (ip->ip_off & htons(IP_MF | IP_OFFMASK)) {
                /* XXXGL: shouldn't we save & set m_flags? */
                m = ip_reass(m);
                if (m == NULL)
                        return;
                ip = mtod(m, struct ip *);
                /* Get the header length of the reassembled packet */
                hlen = ip->ip_hl << 2;
        }

#if defined(IPSEC) || defined(IPSEC_SUPPORT)
        if (IPSEC_ENABLED(ipv4)) {
                if (IPSEC_INPUT(ipv4, m, hlen, ip->ip_p) != 0)
                        return;
        }
#endif /* IPSEC */

        /*
         * Switch out to protocol's input routine.
         */
        IPSTAT_INC(ips_delivered);

        ip_protox[ip->ip_p](&m, &hlen, ip->ip_p);
        return;
bad:
        m_freem(m);
}

int
ipproto_register(uint8_t proto, ipproto_input_t input, ipproto_ctlinput_t ctl)
{

        MPASS(proto > 0);

        /*
         * The protocol slot must not be occupied by another protocol
         * already.  An index pointing to rip_input() is unused.
         */
        if (ip_protox[proto] == rip_input) {
                ip_protox[proto] = input;
                ip_ctlprotox[proto] = ctl;
                return (0);
        } else
                return (EEXIST);
}

int
ipproto_unregister(uint8_t proto)
{

        MPASS(proto > 0);

        if (ip_protox[proto] != rip_input) {
                ip_protox[proto] = rip_input;
                ip_ctlprotox[proto] = rip_ctlinput;
                return (0);
        } else
                return (ENOENT);
}

/*
 * Forward a packet.  If some error occurs return the sender
 * an icmp packet.  Note we can't always generate a meaningful
 * icmp message because icmp doesn't have a large enough repertoire
 * of codes and types.
 *
 * If not forwarding, just drop the packet.  This could be confusing
 * if ipforwarding was zero but some routing protocol was advancing
 * us as a gateway to somewhere.  However, we must let the routing
 * protocol deal with that.
 *
 * The srcrt parameter indicates whether the packet is being forwarded
 * via a source route.
 */
void
ip_forward(struct mbuf *m, int srcrt)
{
        struct ip *ip = mtod(m, struct ip *);
        struct in_ifaddr *ia;
        struct mbuf *mcopy;
        struct sockaddr_in *sin;
        struct in_addr dest;
        struct route ro;
        uint32_t flowid;
        int error, type = 0, code = 0, mtu = 0;

        NET_EPOCH_ASSERT();

        if (m->m_flags & (M_BCAST|M_MCAST) || !in_canforward(ip->ip_dst)) {
                IPSTAT_INC(ips_cantforward);
                m_freem(m);
                return;
        }
        if (
#ifdef IPSTEALTH
            V_ipstealth == 0 &&
#endif
            ip->ip_ttl <= IPTTLDEC) {
                icmp_error(m, ICMP_TIMXCEED, ICMP_TIMXCEED_INTRANS, 0, 0);
                return;
        }

        bzero(&ro, sizeof(ro));
        sin = (struct sockaddr_in *)&ro.ro_dst;
        sin->sin_family = AF_INET;
        sin->sin_len = sizeof(*sin);
        sin->sin_addr = ip->ip_dst;
        flowid = m->m_pkthdr.flowid;
        ro.ro_nh = fib4_lookup(M_GETFIB(m), ip->ip_dst, 0, NHR_REF, flowid);
        if (ro.ro_nh != NULL) {
                if (ro.ro_nh->nh_flags & (NHF_BLACKHOLE | NHF_BROADCAST)) {
                        IPSTAT_INC(ips_cantforward);
                        m_freem(m);
                        NH_FREE(ro.ro_nh);
                        return;
                }
                if (ro.ro_nh->nh_flags & NHF_REJECT) {
                        IPSTAT_INC(ips_cantforward);
                        NH_FREE(ro.ro_nh);
                        icmp_error(m, ICMP_UNREACH, ICMP_UNREACH_HOST, 0, 0);
                        return;
                }
                ia = ifatoia(ro.ro_nh->nh_ifa);
        } else
                ia = NULL;
        /*
         * Save the IP header and at most 8 bytes of the payload,
         * in case we need to generate an ICMP message to the src.
         *
         * XXX this can be optimized a lot by saving the data in a local
         * buffer on the stack (72 bytes at most), and only allocating the
         * mbuf if really necessary. The vast majority of the packets
         * are forwarded without having to send an ICMP back (either
         * because unnecessary, or because rate limited), so we are
         * really we are wasting a lot of work here.
         *
         * We don't use m_copym() because it might return a reference
         * to a shared cluster. Both this function and ip_output()
         * assume exclusive access to the IP header in `m', so any
         * data in a cluster may change before we reach icmp_error().
         */
        mcopy = m_gethdr(M_NOWAIT, m->m_type);
        if (mcopy != NULL && !m_dup_pkthdr(mcopy, m, M_NOWAIT)) {
                /*
                 * It's probably ok if the pkthdr dup fails (because
                 * the deep copy of the tag chain failed), but for now
                 * be conservative and just discard the copy since
                 * code below may some day want the tags.
                 */
                m_free(mcopy);
                mcopy = NULL;
        }
        if (mcopy != NULL) {
                mcopy->m_len = min(ntohs(ip->ip_len), M_TRAILINGSPACE(mcopy));
                mcopy->m_pkthdr.len = mcopy->m_len;
                m_copydata(m, 0, mcopy->m_len, mtod(mcopy, caddr_t));
        }
#ifdef IPSTEALTH
        if (V_ipstealth == 0)
#endif
                ip->ip_ttl -= IPTTLDEC;
#if defined(IPSEC) || defined(IPSEC_SUPPORT)
        if (IPSEC_ENABLED(ipv4)) {
                if ((error = IPSEC_FORWARD(ipv4, m)) != 0) {
                        /* mbuf consumed by IPsec */
                        RO_NHFREE(&ro);
                        m_freem(mcopy);
                        if (error != EINPROGRESS)
                                IPSTAT_INC(ips_cantforward);
                        return;
                }
                /* No IPsec processing required */
        }
#endif /* IPSEC */
        /*
         * If forwarding packet using same interface that it came in on,
         * perhaps should send a redirect to sender to shortcut a hop.
         * Only send redirect if source is sending directly to us,
         * and if packet was not source routed (or has any options).
         * Also, don't send redirect if forwarding using a default route
         * or a route modified by a redirect.
         */
        dest.s_addr = 0;
        if (!srcrt && V_ipsendredirects &&
            ia != NULL && ia->ia_ifp == m->m_pkthdr.rcvif) {
                struct nhop_object *nh;

                nh = ro.ro_nh;

                if (nh != NULL && ((nh->nh_flags & (NHF_REDIRECT|NHF_DEFAULT)) == 0)) {
                        struct in_ifaddr *nh_ia = (struct in_ifaddr *)(nh->nh_ifa);
                        u_long src = ntohl(ip->ip_src.s_addr);

                        if (nh_ia != NULL &&
                            (src & nh_ia->ia_subnetmask) == nh_ia->ia_subnet) {
                                /* Router requirements says to only send host redirects */
                                type = ICMP_REDIRECT;
                                code = ICMP_REDIRECT_HOST;
                                if (nh->nh_flags & NHF_GATEWAY) {
                                    if (nh->gw_sa.sa_family == AF_INET)
                                        dest.s_addr = nh->gw4_sa.sin_addr.s_addr;
                                    else /* Do not redirect in case gw is AF_INET6 */
                                        type = 0;
                                } else
                                        dest.s_addr = ip->ip_dst.s_addr;
                        }
                }
        }

        error = ip_output(m, NULL, &ro, IP_FORWARDING, NULL, NULL);

        if (error == EMSGSIZE && ro.ro_nh)
                mtu = ro.ro_nh->nh_mtu;
        RO_NHFREE(&ro);

        if (error)
                IPSTAT_INC(ips_cantforward);
        else {
                IPSTAT_INC(ips_forward);
                if (type)
                        IPSTAT_INC(ips_redirectsent);
                else {
                        if (mcopy)
                                m_freem(mcopy);
                        return;
                }
        }
        if (mcopy == NULL)
                return;

        switch (error) {
        case 0:                         /* forwarded, but need redirect */
                /* type, code set above */
                break;

        case ENETUNREACH:
        case EHOSTUNREACH:
        case ENETDOWN:
        case EHOSTDOWN:
        default:
                type = ICMP_UNREACH;
                code = ICMP_UNREACH_HOST;
                break;

        case EMSGSIZE:
                type = ICMP_UNREACH;
                code = ICMP_UNREACH_NEEDFRAG;
                /*
                 * If the MTU was set before make sure we are below the
                 * interface MTU.
                 * If the MTU wasn't set before use the interface mtu or
                 * fall back to the next smaller mtu step compared to the
                 * current packet size.
                 */
                if (mtu != 0) {
                        if (ia != NULL)
                                mtu = min(mtu, ia->ia_ifp->if_mtu);
                } else {
                        if (ia != NULL)
                                mtu = ia->ia_ifp->if_mtu;
                        else
                                mtu = ip_next_mtu(ntohs(ip->ip_len), 0);
                }
                IPSTAT_INC(ips_cantfrag);
                break;

        case ENOBUFS:
        case EACCES:                    /* ipfw denied packet */
                m_freem(mcopy);
                return;
        }
        icmp_error(mcopy, type, code, dest.s_addr, mtu);
}

#define CHECK_SO_CT(sp, ct) \
    (((sp->so_options & SO_TIMESTAMP) && (sp->so_ts_clock == ct)) ? 1 : 0)

void
ip_savecontrol(struct inpcb *inp, struct mbuf **mp, struct ip *ip,
    struct mbuf *m)
{
        bool stamped;

        stamped = false;
        if ((inp->inp_socket->so_options & SO_BINTIME) ||
            CHECK_SO_CT(inp->inp_socket, SO_TS_BINTIME)) {
                struct bintime boottimebin, bt;
                struct timespec ts1;

                if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
                    M_TSTMP)) {
                        mbuf_tstmp2timespec(m, &ts1);
                        timespec2bintime(&ts1, &bt);
                        getboottimebin(&boottimebin);
                        bintime_add(&bt, &boottimebin);
                } else {
                        bintime(&bt);
                }
                *mp = sbcreatecontrol(&bt, sizeof(bt), SCM_BINTIME,
                    SOL_SOCKET, M_NOWAIT);
                if (*mp != NULL) {
                        mp = &(*mp)->m_next;
                        stamped = true;
                }
        }
        if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME_MICRO)) {
                struct bintime boottimebin, bt1;
                struct timespec ts1;
                struct timeval tv;

                if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
                    M_TSTMP)) {
                        mbuf_tstmp2timespec(m, &ts1);
                        timespec2bintime(&ts1, &bt1);
                        getboottimebin(&boottimebin);
                        bintime_add(&bt1, &boottimebin);
                        bintime2timeval(&bt1, &tv);
                } else {
                        microtime(&tv);
                }
                *mp = sbcreatecontrol((caddr_t)&tv, sizeof(tv), SCM_TIMESTAMP,
                    SOL_SOCKET, M_NOWAIT);
                if (*mp != NULL) {
                        mp = &(*mp)->m_next;
                        stamped = true;
                }
        } else if (CHECK_SO_CT(inp->inp_socket, SO_TS_REALTIME)) {
                struct bintime boottimebin;
                struct timespec ts, ts1;

                if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
                    M_TSTMP)) {
                        mbuf_tstmp2timespec(m, &ts);
                        getboottimebin(&boottimebin);
                        bintime2timespec(&boottimebin, &ts1);
                        timespecadd(&ts, &ts1, &ts);
                } else {
                        nanotime(&ts);
                }
                *mp = sbcreatecontrol(&ts, sizeof(ts), SCM_REALTIME,
                    SOL_SOCKET, M_NOWAIT);
                if (*mp != NULL) {
                        mp = &(*mp)->m_next;
                        stamped = true;
                }
        } else if (CHECK_SO_CT(inp->inp_socket, SO_TS_MONOTONIC)) {
                struct timespec ts;

                if ((m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
                    M_TSTMP))
                        mbuf_tstmp2timespec(m, &ts);
                else
                        nanouptime(&ts);
                *mp = sbcreatecontrol(&ts, sizeof(ts), SCM_MONOTONIC,
                    SOL_SOCKET, M_NOWAIT);
                if (*mp != NULL) {
                        mp = &(*mp)->m_next;
                        stamped = true;
                }
        }
        if (stamped && (m->m_flags & (M_PKTHDR | M_TSTMP)) == (M_PKTHDR |
            M_TSTMP)) {
                struct sock_timestamp_info sti;

                bzero(&sti, sizeof(sti));
                sti.st_info_flags = ST_INFO_HW;
                if ((m->m_flags & M_TSTMP_HPREC) != 0)
                        sti.st_info_flags |= ST_INFO_HW_HPREC;
                *mp = sbcreatecontrol(&sti, sizeof(sti), SCM_TIME_INFO,
                    SOL_SOCKET, M_NOWAIT);
                if (*mp != NULL)
                        mp = &(*mp)->m_next;
        }
        if (inp->inp_flags & INP_RECVDSTADDR) {
                *mp = sbcreatecontrol(&ip->ip_dst, sizeof(struct in_addr),
                    IP_RECVDSTADDR, IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }
        if (inp->inp_flags & INP_RECVTTL) {
                *mp = sbcreatecontrol(&ip->ip_ttl, sizeof(u_char), IP_RECVTTL,
                    IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }
#ifdef notyet
        /* XXX
         * Moving these out of udp_input() made them even more broken
         * than they already were.
         */
        /* options were tossed already */
        if (inp->inp_flags & INP_RECVOPTS) {
                *mp = sbcreatecontrol(opts_deleted_above,
                    sizeof(struct in_addr), IP_RECVOPTS, IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }
        /* ip_srcroute doesn't do what we want here, need to fix */
        if (inp->inp_flags & INP_RECVRETOPTS) {
                *mp = sbcreatecontrol(ip_srcroute(m), sizeof(struct in_addr),
                    IP_RECVRETOPTS, IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }
#endif
        if (inp->inp_flags & INP_RECVIF) {
                struct ifnet *ifp;
                struct sdlbuf {
                        struct sockaddr_dl sdl;
                        u_char  pad[32];
                } sdlbuf;
                struct sockaddr_dl *sdp;
                struct sockaddr_dl *sdl2 = &sdlbuf.sdl;

                if ((ifp = m->m_pkthdr.rcvif)) {
                        sdp = (struct sockaddr_dl *)ifp->if_addr->ifa_addr;
                        /*
                         * Change our mind and don't try copy.
                         */
                        if (sdp->sdl_family != AF_LINK ||
                            sdp->sdl_len > sizeof(sdlbuf)) {
                                goto makedummy;
                        }
                        bcopy(sdp, sdl2, sdp->sdl_len);
                } else {
makedummy:
                        sdl2->sdl_len =
                            offsetof(struct sockaddr_dl, sdl_data[0]);
                        sdl2->sdl_family = AF_LINK;
                        sdl2->sdl_index = 0;
                        sdl2->sdl_nlen = sdl2->sdl_alen = sdl2->sdl_slen = 0;
                }
                *mp = sbcreatecontrol(sdl2, sdl2->sdl_len, IP_RECVIF,
                    IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }
        if (inp->inp_flags & INP_RECVTOS) {
                *mp = sbcreatecontrol(&ip->ip_tos, sizeof(u_char), IP_RECVTOS,
                    IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }

        if (inp->inp_flags2 & INP_RECVFLOWID) {
                uint32_t flowid, flow_type;

                flowid = m->m_pkthdr.flowid;
                flow_type = M_HASHTYPE_GET(m);

                /*
                 * XXX should handle the failure of one or the
                 * other - don't populate both?
                 */
                *mp = sbcreatecontrol(&flowid, sizeof(uint32_t), IP_FLOWID,
                    IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
                *mp = sbcreatecontrol(&flow_type, sizeof(uint32_t),
                    IP_FLOWTYPE, IPPROTO_IP, M_NOWAIT);
                if (*mp)
                        mp = &(*mp)->m_next;
        }

#ifdef  RSS
        if (inp->inp_flags2 & INP_RECVRSSBUCKETID) {
                uint32_t flowid, flow_type;
                uint32_t rss_bucketid;

                flowid = m->m_pkthdr.flowid;
                flow_type = M_HASHTYPE_GET(m);

                if (rss_hash2bucket(flowid, flow_type, &rss_bucketid) == 0) {
                        *mp = sbcreatecontrol(&rss_bucketid, sizeof(uint32_t),
                            IP_RSSBUCKETID, IPPROTO_IP, M_NOWAIT);
                        if (*mp)
                                mp = &(*mp)->m_next;
                }
        }
#endif
}

/*
 * XXXRW: Multicast routing code in ip_mroute.c is generally MPSAFE, but the
 * ip_rsvp and ip_rsvp_on variables need to be interlocked with rsvp_on
 * locking.  This code remains in ip_input.c as ip_mroute.c is optionally
 * compiled.
 */
VNET_DEFINE_STATIC(int, ip_rsvp_on);
VNET_DEFINE(struct socket *, ip_rsvpd);

#define V_ip_rsvp_on            VNET(ip_rsvp_on)

int
ip_rsvp_init(struct socket *so)
{

        if (V_ip_rsvpd != NULL)
                return EADDRINUSE;

        V_ip_rsvpd = so;
        /*
         * This may seem silly, but we need to be sure we don't over-increment
         * the RSVP counter, in case something slips up.
         */
        if (!V_ip_rsvp_on) {
                V_ip_rsvp_on = 1;
                V_rsvp_on++;
        }

        return 0;
}

int
ip_rsvp_done(void)
{

        V_ip_rsvpd = NULL;
        /*
         * This may seem silly, but we need to be sure we don't over-decrement
         * the RSVP counter, in case something slips up.
         */
        if (V_ip_rsvp_on) {
                V_ip_rsvp_on = 0;
                V_rsvp_on--;
        }
        return 0;
}

int
rsvp_input(struct mbuf **mp, int *offp, int proto)
{
        struct mbuf *m;

        m = *mp;
        *mp = NULL;

        if (rsvp_input_p) { /* call the real one if loaded */
                *mp = m;
                rsvp_input_p(mp, offp, proto);
                return (IPPROTO_DONE);
        }

        /* Can still get packets with rsvp_on = 0 if there is a local member
         * of the group to which the RSVP packet is addressed.  But in this
         * case we want to throw the packet away.
         */

        if (!V_rsvp_on) {
                m_freem(m);
                return (IPPROTO_DONE);
        }

        if (V_ip_rsvpd != NULL) {
                *mp = m;
                rip_input(mp, offp, proto);
                return (IPPROTO_DONE);
        }
        /* Drop the packet */
        m_freem(m);
        return (IPPROTO_DONE);
}