/*      $OpenBSD: if_pflow.c,v 1.100 2023/11/09 08:53:20 mvs Exp $      */

/*
 * Copyright (c) 2023 Rubicon Communications, LLC (Netgate)
 * Copyright (c) 2011 Florian Obser <florian@narrans.de>
 * Copyright (c) 2011 Sebastian Benoit <benoit-lists@fb12.de>
 * Copyright (c) 2008 Henning Brauer <henning@openbsd.org>
 * Copyright (c) 2008 Joerg Goltermann <jg@osn.de>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER IN
 * AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
 * OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/cdefs.h>
#include <sys/param.h>
#include <sys/bus.h>
#include <sys/callout.h>
#include <sys/endian.h>
#include <sys/interrupt.h>
#include <sys/jail.h>
#include <sys/kernel.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mbuf.h>
#include <sys/socket.h>
#include <sys/socketvar.h>
#include <sys/sockio.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/priv.h>

#include <net/if.h>
#include <net/if_types.h>
#include <net/bpf.h>
#include <net/route.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
#include <netinet/tcp.h>

#include <netinet/ip.h>
#include <netinet/ip_icmp.h>
#include <netinet/ip_var.h>
#include <netinet/udp.h>
#include <netinet/udp_var.h>
#include <netinet/in_pcb.h>

#include <netlink/netlink.h>
#include <netlink/netlink_ctl.h>
#include <netlink/netlink_generic.h>
#include <netlink/netlink_message_writer.h>

#include <net/pfvar.h>
#include <net/pflow.h>
#include "net/if_var.h"

#define PFLOW_MINMTU    \
    (sizeof(struct pflow_header) + sizeof(struct pflow_flow))

#ifdef PFLOWDEBUG
#define DPRINTF(x)      do { printf x ; } while (0)
#else
#define DPRINTF(x)
#endif

enum pflow_family_t {
        PFLOW_INET,
        PFLOW_INET6,
        PFLOW_NAT4,
};

static void     pflow_output_process(void *);
static int      pflow_create(int);
static int      pflow_destroy(int, bool);
static int      pflow_calc_mtu(struct pflow_softc *, int, int);
static void     pflow_setmtu(struct pflow_softc *, int);
static int      pflowvalidsockaddr(const struct sockaddr *, int);

static struct mbuf      *pflow_get_mbuf(struct pflow_softc *, u_int16_t);
static void     pflow_flush(struct pflow_softc *);
static int      pflow_sendout_v5(struct pflow_softc *);
static int      pflow_sendout_ipfix(struct pflow_softc *, enum pflow_family_t);
static int      pflow_sendout_ipfix_tmpl(struct pflow_softc *);
static int      pflow_sendout_mbuf(struct pflow_softc *, struct mbuf *);
static int      sysctl_pflowstats(SYSCTL_HANDLER_ARGS);
static void     pflow_timeout(void *);
static void     pflow_timeout6(void *);
static void     pflow_timeout_tmpl(void *);
static void     pflow_timeout_nat4(void *);
static void     copy_flow_data(struct pflow_flow *, struct pflow_flow *,
        const struct pf_kstate *, struct pf_state_key *, int, int);
static void     copy_flow_ipfix_4_data(struct pflow_ipfix_flow4 *,
        struct pflow_ipfix_flow4 *, const struct pf_kstate *, struct pf_state_key *,
        struct pflow_softc *, int, int);
static void     copy_flow_ipfix_6_data(struct pflow_ipfix_flow6 *,
        struct pflow_ipfix_flow6 *, const struct pf_kstate *, struct pf_state_key *,
        struct pflow_softc *, int, int);
static int      pflow_pack_flow(const struct pf_kstate *, struct pf_state_key *,
        struct pflow_softc *);
static int      pflow_pack_flow_ipfix(const struct pf_kstate *, struct pf_state_key *,
        struct pflow_softc *);
static void     export_pflow(const struct pf_kstate *);
static int      export_pflow_if(const struct pf_kstate*, struct pf_state_key *,
        struct pflow_softc *);
static int      copy_flow_to_m(struct pflow_flow *flow, struct pflow_softc *sc);
static int      copy_flow_ipfix_4_to_m(struct pflow_ipfix_flow4 *flow,
        struct pflow_softc *sc);
static int      copy_flow_ipfix_6_to_m(struct pflow_ipfix_flow6 *flow,
        struct pflow_softc *sc);
static int      copy_nat_ipfix_4_to_m(struct pflow_ipfix_nat4 *,
        const struct pf_kstate *, struct pflow_softc *,
        uint8_t, uint64_t);

static const char pflowname[] = "pflow";

enum pflowstat_counters {
        pflow_flows,
        pflow_packets,
        pflow_onomem,
        pflow_oerrors,
        pflow_ncounters,
};
struct pflowstats_ctr {
        counter_u64_t   c[pflow_ncounters];
};

/**
 * Locking concept
 *
 * The list of pflow devices (V_pflowif_list) is managed through epoch.
 * It is safe to read the list without locking (while in NET_EPOCH).
 * There may only be one simultaneous modifier, hence we need V_pflow_list_mtx
 * on every add/delete.
 *
 * Each pflow interface protects its own data with the sc_lock mutex.
 *
 * We do not require any pf locks, and in fact expect to be called without
 * hashrow locks held.
 **/

VNET_DEFINE(struct unrhdr *,    pflow_unr);
#define V_pflow_unr     VNET(pflow_unr)
VNET_DEFINE(CK_LIST_HEAD(, pflow_softc), pflowif_list);
#define V_pflowif_list  VNET(pflowif_list)
VNET_DEFINE(struct mtx, pflowif_list_mtx);
#define V_pflowif_list_mtx      VNET(pflowif_list_mtx)
VNET_DEFINE(struct pflowstats_ctr,       pflowstat);
#define V_pflowstats    VNET(pflowstat)

#define PFLOW_LOCK(_sc)         mtx_lock(&(_sc)->sc_lock)
#define PFLOW_UNLOCK(_sc)       mtx_unlock(&(_sc)->sc_lock)
#define PFLOW_ASSERT(_sc)       mtx_assert(&(_sc)->sc_lock, MA_OWNED)

SYSCTL_NODE(_net, OID_AUTO, pflow, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
    "PFLOW");
SYSCTL_PROC(_net_pflow, OID_AUTO, stats, CTLTYPE_OPAQUE | CTLFLAG_RD | CTLFLAG_MPSAFE,
    0, 0, sysctl_pflowstats, "S,pflowstats",
    "PFLOW statistics (struct pflowstats, net/if_pflow.h)");

static inline void
pflowstat_inc(enum pflowstat_counters c)
{
        counter_u64_add(V_pflowstats.c[c], 1);
}

static void
vnet_pflowattach(void)
{
        CK_LIST_INIT(&V_pflowif_list);
        mtx_init(&V_pflowif_list_mtx, "pflow interface list mtx", NULL, MTX_DEF);

        V_pflow_unr = new_unrhdr(0, PFLOW_MAX_ENTRIES - 1, &V_pflowif_list_mtx);

        for (int i = 0; i < pflow_ncounters; i++)
                V_pflowstats.c[i] = counter_u64_alloc(M_WAITOK);
}
VNET_SYSINIT(vnet_pflowattach, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY,
    vnet_pflowattach, NULL);

static int
pflow_jail_remove(void *obj, void *data __unused)
{
#ifdef VIMAGE
        const struct prison *pr = obj;
#endif
        struct pflow_softc      *sc, *tmp;

        CURVNET_SET(pr->pr_vnet);
        CK_LIST_FOREACH_SAFE(sc, &V_pflowif_list, sc_next, tmp) {
                pflow_destroy(sc->sc_id, false);
        }
        CURVNET_RESTORE();

        return (0);
}

static void
vnet_pflowdetach(void)
{

        /* Should have been done by pflow_jail_remove() */
        MPASS(CK_LIST_EMPTY(&V_pflowif_list));
        delete_unrhdr(V_pflow_unr);
        mtx_destroy(&V_pflowif_list_mtx);

        for (int i = 0; i < pflow_ncounters; i++)
                counter_u64_free(V_pflowstats.c[i]);
}
VNET_SYSUNINIT(vnet_pflowdetach, SI_SUB_PROTO_FIREWALL, SI_ORDER_FOURTH,
    vnet_pflowdetach, NULL);

static void
vnet_pflow_finalise(void)
{
        /*
         * Ensure we've freed all interfaces, and do not have pending
         * epoch cleanup calls.
         */
        NET_EPOCH_DRAIN_CALLBACKS();
}
VNET_SYSUNINIT(vnet_pflow_finalise, SI_SUB_PROTO_FIREWALL, SI_ORDER_THIRD,
    vnet_pflow_finalise, NULL);

static void
pflow_output_process(void *arg)
{
        struct mbufq ml;
        struct pflow_softc *sc = arg;
        struct mbuf *m;

        mbufq_init(&ml, 0);

        PFLOW_LOCK(sc);
        mbufq_concat(&ml, &sc->sc_outputqueue);
        PFLOW_UNLOCK(sc);

        CURVNET_SET(sc->sc_vnet);
        while ((m = mbufq_dequeue(&ml)) != NULL) {
                pflow_sendout_mbuf(sc, m);
        }
        CURVNET_RESTORE();
}

static int
pflow_create(int unit)
{
        struct pflow_softc      *pflowif;
        int                      error;

        pflowif = malloc(sizeof(*pflowif), M_DEVBUF, M_WAITOK|M_ZERO);
        mtx_init(&pflowif->sc_lock, "pflowlk", NULL, MTX_DEF);
        pflowif->sc_version = PFLOW_PROTO_DEFAULT;
        pflowif->sc_observation_dom = PFLOW_ENGINE_TYPE;

        /* ipfix template init */
        bzero(&pflowif->sc_tmpl_ipfix,sizeof(pflowif->sc_tmpl_ipfix));
        pflowif->sc_tmpl_ipfix.set_header.set_id =
            htons(PFLOW_IPFIX_TMPL_SET_ID);
        pflowif->sc_tmpl_ipfix.set_header.set_length =
            htons(sizeof(struct pflow_ipfix_tmpl));

        /* ipfix IPv4 template */
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.h.tmpl_id =
            htons(PFLOW_IPFIX_TMPL_IPV4_ID);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.h.field_count
            = htons(PFLOW_IPFIX_TMPL_IPV4_FIELD_COUNT);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.src_ip.field_id =
            htons(PFIX_IE_sourceIPv4Address);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.src_ip.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.dest_ip.field_id =
            htons(PFIX_IE_destinationIPv4Address);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.dest_ip.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.if_index_in.field_id =
            htons(PFIX_IE_ingressInterface);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.if_index_in.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.if_index_out.field_id =
            htons(PFIX_IE_egressInterface);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.if_index_out.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.packets.field_id =
            htons(PFIX_IE_packetDeltaCount);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.packets.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.octets.field_id =
            htons(PFIX_IE_octetDeltaCount);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.octets.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.start.field_id =
            htons(PFIX_IE_flowStartMilliseconds);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.start.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.finish.field_id =
            htons(PFIX_IE_flowEndMilliseconds);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.finish.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.src_port.field_id =
            htons(PFIX_IE_sourceTransportPort);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.src_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.dest_port.field_id =
            htons(PFIX_IE_destinationTransportPort);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.dest_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.tos.field_id =
            htons(PFIX_IE_ipClassOfService);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.tos.len = htons(1);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.protocol.field_id =
            htons(PFIX_IE_protocolIdentifier);
        pflowif->sc_tmpl_ipfix.ipv4_tmpl.protocol.len = htons(1);

        /* ipfix IPv6 template */
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.h.tmpl_id =
            htons(PFLOW_IPFIX_TMPL_IPV6_ID);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.h.field_count =
            htons(PFLOW_IPFIX_TMPL_IPV6_FIELD_COUNT);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.src_ip.field_id =
            htons(PFIX_IE_sourceIPv6Address);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.src_ip.len = htons(16);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.dest_ip.field_id =
            htons(PFIX_IE_destinationIPv6Address);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.dest_ip.len = htons(16);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.if_index_in.field_id =
            htons(PFIX_IE_ingressInterface);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.if_index_in.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.if_index_out.field_id =
            htons(PFIX_IE_egressInterface);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.if_index_out.len = htons(4);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.packets.field_id =
            htons(PFIX_IE_packetDeltaCount);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.packets.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.octets.field_id =
            htons(PFIX_IE_octetDeltaCount);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.octets.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.start.field_id =
            htons(PFIX_IE_flowStartMilliseconds);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.start.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.finish.field_id =
            htons(PFIX_IE_flowEndMilliseconds);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.finish.len = htons(8);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.src_port.field_id =
            htons(PFIX_IE_sourceTransportPort);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.src_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.dest_port.field_id =
            htons(PFIX_IE_destinationTransportPort);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.dest_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.tos.field_id =
            htons(PFIX_IE_ipClassOfService);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.tos.len = htons(1);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.protocol.field_id =
            htons(PFIX_IE_protocolIdentifier);
        pflowif->sc_tmpl_ipfix.ipv6_tmpl.protocol.len = htons(1);

        /* NAT44 create template */
        pflowif->sc_tmpl_ipfix.nat44_tmpl.h.tmpl_id =
            htons(PFLOW_IPFIX_TMPL_NAT44_ID);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.h.field_count =
            htons(PFLOW_IPFIX_TMPL_NAT44_FIELD_COUNT);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.timestamp.field_id =
            htons(PFIX_IE_timeStamp);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.timestamp.len =
            htons(8);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.nat_event.field_id =
            htons(PFIX_IE_natEvent);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.nat_event.len =
            htons(1);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.protocol.field_id =
            htons(PFIX_IE_protocolIdentifier);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.protocol.len = htons(1);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.src_ip.field_id =
            htons(PFIX_IE_sourceIPv4Address);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.src_ip.len =
            htons(4);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.src_port.field_id =
            htons(PFIX_IE_sourceTransportPort);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.src_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_src_ip.field_id =
            htons(PFIX_IE_postNATSourceIPv4Address);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_src_ip.len =
            htons(4);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_src_port.field_id =
            htons(PFIX_IE_postNAPTSourceTransportPort);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_src_port.len =
            htons(2);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.dst_ip.field_id =
            htons(PFIX_IE_destinationIPv4Address);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.dst_ip.len =
            htons(4);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.dst_port.field_id =
            htons(PFIX_IE_destinationTransportPort);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.dst_port.len = htons(2);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_dst_ip.field_id =
            htons(PFIX_IE_postNATDestinationIPv4Address);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_dst_ip.len =
            htons(4);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_dst_port.field_id =
            htons(PFIX_IE_postNAPTDestinationTransportPort);
        pflowif->sc_tmpl_ipfix.nat44_tmpl.postnat_dst_port.len =
            htons(2);

        pflowif->sc_id = unit;
        pflowif->sc_vnet = curvnet;

        mbufq_init(&pflowif->sc_outputqueue, 8192);
        pflow_setmtu(pflowif, ETHERMTU);

        callout_init_mtx(&pflowif->sc_tmo, &pflowif->sc_lock, 0);
        callout_init_mtx(&pflowif->sc_tmo6, &pflowif->sc_lock, 0);
        callout_init_mtx(&pflowif->sc_tmo_nat4, &pflowif->sc_lock, 0);
        callout_init_mtx(&pflowif->sc_tmo_tmpl, &pflowif->sc_lock, 0);

        error = swi_add(&pflowif->sc_swi_ie, pflowname, pflow_output_process,
            pflowif, SWI_NET, INTR_MPSAFE, &pflowif->sc_swi_cookie);
        if (error) {
                free(pflowif, M_DEVBUF);
                return (error);
        }

        /* Insert into list of pflows */
        mtx_lock(&V_pflowif_list_mtx);
        CK_LIST_INSERT_HEAD(&V_pflowif_list, pflowif, sc_next);
        mtx_unlock(&V_pflowif_list_mtx);

        V_pflow_export_state_ptr = export_pflow;

        return (0);
}

static void
pflow_free_cb(struct epoch_context *ctx)
{
        struct pflow_softc *sc;

        sc = __containerof(ctx, struct pflow_softc, sc_epoch_ctx);

        free(sc, M_DEVBUF);
}

static int
pflow_destroy(int unit, bool drain)
{
        struct pflow_softc      *sc;
        int                      error __diagused;

        mtx_lock(&V_pflowif_list_mtx);
        CK_LIST_FOREACH(sc, &V_pflowif_list, sc_next) {
                if (sc->sc_id == unit)
                        break;
        }
        if (sc == NULL) {
                mtx_unlock(&V_pflowif_list_mtx);
                return (ENOENT);
        }
        CK_LIST_REMOVE(sc, sc_next);
        if (CK_LIST_EMPTY(&V_pflowif_list))
                V_pflow_export_state_ptr = NULL;
        mtx_unlock(&V_pflowif_list_mtx);

        sc->sc_dying = 1;

        if (drain) {
                /* Let's be sure no one is using this interface any more. */
                NET_EPOCH_DRAIN_CALLBACKS();
        }

        error = swi_remove(sc->sc_swi_cookie);
        MPASS(error == 0);
        error = intr_event_destroy(sc->sc_swi_ie);
        MPASS(error == 0);

        callout_drain(&sc->sc_tmo);
        callout_drain(&sc->sc_tmo6);
        callout_drain(&sc->sc_tmo_nat4);
        callout_drain(&sc->sc_tmo_tmpl);

        m_freem(sc->sc_mbuf);
        m_freem(sc->sc_mbuf6);
        m_freem(sc->sc_mbuf_nat4);

        PFLOW_LOCK(sc);
        mbufq_drain(&sc->sc_outputqueue);
        if (sc->so != NULL) {
                soclose(sc->so);
                sc->so = NULL;
        }
        if (sc->sc_flowdst != NULL)
                free(sc->sc_flowdst, M_DEVBUF);
        if (sc->sc_flowsrc != NULL)
                free(sc->sc_flowsrc, M_DEVBUF);
        PFLOW_UNLOCK(sc);

        mtx_destroy(&sc->sc_lock);

        free_unr(V_pflow_unr, unit);

        NET_EPOCH_CALL(pflow_free_cb, &sc->sc_epoch_ctx);

        return (0);
}

static int
pflowvalidsockaddr(const struct sockaddr *sa, int ignore_port)
{
        const struct sockaddr_in6       *sin6;
        const struct sockaddr_in        *sin;

        if (sa == NULL)
                return (0);
        switch(sa->sa_family) {
        case AF_INET:
                sin = (const struct sockaddr_in *)sa;
                return (sin->sin_addr.s_addr != INADDR_ANY &&
                    (ignore_port || sin->sin_port != 0));
        case AF_INET6:
                sin6 = (const struct sockaddr_in6 *)sa;
                return (!IN6_IS_ADDR_UNSPECIFIED(&sin6->sin6_addr) &&
                    (ignore_port || sin6->sin6_port != 0));
        default:
                return (0);
        }
}

int
pflow_calc_mtu(struct pflow_softc *sc, int mtu, int hdrsz)
{
        size_t min;

        sc->sc_maxcount4 = (mtu - hdrsz -
            sizeof(struct udpiphdr)) / sizeof(struct pflow_ipfix_flow4);
        sc->sc_maxcount6 = (mtu - hdrsz -
            sizeof(struct udpiphdr)) / sizeof(struct pflow_ipfix_flow6);
        sc->sc_maxcount_nat4 = (mtu - hdrsz -
            sizeof(struct udpiphdr)) / sizeof(struct pflow_ipfix_nat4);
        if (sc->sc_maxcount4 > PFLOW_MAXFLOWS)
                sc->sc_maxcount4 = PFLOW_MAXFLOWS;
        if (sc->sc_maxcount6 > PFLOW_MAXFLOWS)
                sc->sc_maxcount6 = PFLOW_MAXFLOWS;
        if (sc->sc_maxcount_nat4 > PFLOW_MAXFLOWS)
                sc->sc_maxcount_nat4 = PFLOW_MAXFLOWS;

        min = MIN(sc->sc_maxcount4 * sizeof(struct pflow_ipfix_flow4),
            sc->sc_maxcount6 * sizeof(struct pflow_ipfix_flow6));
        min = MIN(min, sc->sc_maxcount_nat4 * sizeof(struct pflow_ipfix_nat4));

        return (hdrsz + sizeof(struct udpiphdr) + min);
}

static void
pflow_setmtu(struct pflow_softc *sc, int mtu_req)
{
        int     mtu;

        mtu = mtu_req;

        switch (sc->sc_version) {
        case PFLOW_PROTO_5:
                sc->sc_maxcount = (mtu - sizeof(struct pflow_header) -
                    sizeof(struct udpiphdr)) / sizeof(struct pflow_flow);
                if (sc->sc_maxcount > PFLOW_MAXFLOWS)
                    sc->sc_maxcount = PFLOW_MAXFLOWS;
                break;
        case PFLOW_PROTO_10:
                pflow_calc_mtu(sc, mtu, sizeof(struct pflow_v10_header));
                break;
        default: /* NOTREACHED */
                break;
        }
}

static struct mbuf *
pflow_get_mbuf(struct pflow_softc *sc, u_int16_t set_id)
{
        struct pflow_set_header  set_hdr;
        struct pflow_header      h;
        struct mbuf             *m;

        MGETHDR(m, M_NOWAIT, MT_DATA);
        if (m == NULL) {
                pflowstat_inc(pflow_onomem);
                return (NULL);
        }

        MCLGET(m, M_NOWAIT);
        if ((m->m_flags & M_EXT) == 0) {
                m_free(m);
                pflowstat_inc(pflow_onomem);
                return (NULL);
        }

        m->m_len = m->m_pkthdr.len = 0;

        if (sc == NULL)         /* get only a new empty mbuf */
                return (m);

        switch (sc->sc_version) {
        case PFLOW_PROTO_5:
                /* populate pflow_header */
                h.reserved1 = 0;
                h.reserved2 = 0;
                h.count = 0;
                h.version = htons(PFLOW_PROTO_5);
                h.flow_sequence = htonl(sc->sc_gcounter);
                h.engine_type = PFLOW_ENGINE_TYPE;
                h.engine_id = PFLOW_ENGINE_ID;
                m_copyback(m, 0, PFLOW_HDRLEN, (caddr_t)&h);

                sc->sc_count = 0;
                callout_reset(&sc->sc_tmo, PFLOW_TIMEOUT * hz,
                    pflow_timeout, sc);
                break;
        case PFLOW_PROTO_10:
                /* populate pflow_set_header */
                set_hdr.set_length = 0;
                set_hdr.set_id = htons(set_id);
                m_copyback(m, 0, PFLOW_SET_HDRLEN, (caddr_t)&set_hdr);
                break;
        default: /* NOTREACHED */
                break;
        }

        return (m);
}

static void
copy_flow_data(struct pflow_flow *flow1, struct pflow_flow *flow2,
    const struct pf_kstate *st, struct pf_state_key *sk, int src, int dst)
{
        flow1->src_ip = flow2->dest_ip = sk->addr[src].v4.s_addr;
        flow1->src_port = flow2->dest_port = sk->port[src];
        flow1->dest_ip = flow2->src_ip = sk->addr[dst].v4.s_addr;
        flow1->dest_port = flow2->src_port = sk->port[dst];

        flow1->dest_as = flow2->src_as =
            flow1->src_as = flow2->dest_as = 0;
        flow1->if_index_in = htons(st->if_index_in);
        flow1->if_index_out = htons(st->if_index_out);
        flow2->if_index_in = htons(st->if_index_out);
        flow2->if_index_out = htons(st->if_index_in);
        flow1->dest_mask = flow2->src_mask =
            flow1->src_mask = flow2->dest_mask = 0;

        flow1->flow_packets = htonl(st->packets[0]);
        flow2->flow_packets = htonl(st->packets[1]);
        flow1->flow_octets = htonl(st->bytes[0]);
        flow2->flow_octets = htonl(st->bytes[1]);

        /*
         * Pretend the flow was created or expired when the machine came up
         * when creation is in the future of the last time a package was seen
         * or was created / expired before this machine came up due to pfsync.
         */
        flow1->flow_start = flow2->flow_start = st->creation < 0 ||
            st->creation > st->expire ? htonl(0) : htonl(st->creation);
        flow1->flow_finish = flow2->flow_finish = st->expire < 0 ? htonl(0) :
            htonl(st->expire);
        flow1->tcp_flags = flow2->tcp_flags = 0;
        flow1->protocol = flow2->protocol = sk->proto;
        flow1->tos = flow2->tos = st->rule->tos;
}

static void
copy_flow_ipfix_4_data(struct pflow_ipfix_flow4 *flow1,
    struct pflow_ipfix_flow4 *flow2, const struct pf_kstate *st,
    struct pf_state_key *sk, struct pflow_softc *sc, int src, int dst)
{
        flow1->src_ip = flow2->dest_ip = sk->addr[src].v4.s_addr;
        flow1->src_port = flow2->dest_port = sk->port[src];
        flow1->dest_ip = flow2->src_ip = sk->addr[dst].v4.s_addr;
        flow1->dest_port = flow2->src_port = sk->port[dst];

        flow1->if_index_in = htonl(st->if_index_in);
        flow1->if_index_out = htonl(st->if_index_out);
        flow2->if_index_in = htonl(st->if_index_out);
        flow2->if_index_out = htonl(st->if_index_in);

        flow1->flow_packets = htobe64(st->packets[0]);
        flow2->flow_packets = htobe64(st->packets[1]);
        flow1->flow_octets = htobe64(st->bytes[0]);
        flow2->flow_octets = htobe64(st->bytes[1]);

        /*
         * Pretend the flow was created when the machine came up when creation
         * is in the future of the last time a package was seen due to pfsync.
         */
        if (st->creation > st->expire)
                flow1->flow_start = flow2->flow_start = htobe64((time_second -
                    time_uptime)*1000);
        else
                flow1->flow_start = flow2->flow_start = htobe64((pf_get_time() -
                    (pf_get_uptime() - st->creation)));
        flow1->flow_finish = flow2->flow_finish = htobe64((pf_get_time() -
            (pf_get_uptime() - st->expire)));

        flow1->protocol = flow2->protocol = sk->proto;
        flow1->tos = flow2->tos = st->rule->tos;
}

static void
copy_flow_ipfix_6_data(struct pflow_ipfix_flow6 *flow1,
    struct pflow_ipfix_flow6 *flow2, const struct pf_kstate *st,
    struct pf_state_key *sk, struct pflow_softc *sc, int src, int dst)
{
        bcopy(&sk->addr[src].v6, &flow1->src_ip, sizeof(flow1->src_ip));
        bcopy(&sk->addr[src].v6, &flow2->dest_ip, sizeof(flow2->dest_ip));
        flow1->src_port = flow2->dest_port = sk->port[src];
        bcopy(&sk->addr[dst].v6, &flow1->dest_ip, sizeof(flow1->dest_ip));
        bcopy(&sk->addr[dst].v6, &flow2->src_ip, sizeof(flow2->src_ip));
        flow1->dest_port = flow2->src_port = sk->port[dst];

        flow1->if_index_in = htonl(st->if_index_in);
        flow1->if_index_out = htonl(st->if_index_out);
        flow2->if_index_in = htonl(st->if_index_out);
        flow2->if_index_out = htonl(st->if_index_in);

        flow1->flow_packets = htobe64(st->packets[0]);
        flow2->flow_packets = htobe64(st->packets[1]);
        flow1->flow_octets = htobe64(st->bytes[0]);
        flow2->flow_octets = htobe64(st->bytes[1]);

        /*
         * Pretend the flow was created when the machine came up when creation
         * is in the future of the last time a package was seen due to pfsync.
         */
        if (st->creation > st->expire)
                flow1->flow_start = flow2->flow_start = htobe64((time_second -
                    time_uptime)*1000);
        else
                flow1->flow_start = flow2->flow_start = htobe64((pf_get_time() -
                    (pf_get_uptime() - st->creation)));
        flow1->flow_finish = flow2->flow_finish = htobe64((pf_get_time() -
            (pf_get_uptime() - st->expire)));

        flow1->protocol = flow2->protocol = sk->proto;
        flow1->tos = flow2->tos = st->rule->tos;
}

static void
copy_nat_ipfix_4_data(struct pflow_ipfix_nat4 *nat1,
    struct pflow_ipfix_nat4 *nat2, const struct pf_kstate *st,
    struct pf_state_key *sk, struct pflow_softc *sc, int src, int dst)
{
        nat1->src_ip = nat2->dest_ip = st->key[PF_SK_STACK]->addr[src].v4.s_addr;
        nat1->src_port = nat2->dest_port = st->key[PF_SK_STACK]->port[src];
        nat1->dest_ip = nat2->src_ip = st->key[PF_SK_STACK]->addr[dst].v4.s_addr;
        nat1->dest_port = nat2->src_port = st->key[PF_SK_STACK]->port[dst];
        nat1->postnat_src_ip = nat2->postnat_dest_ip = st->key[PF_SK_WIRE]->addr[src].v4.s_addr;
        nat1->postnat_src_port = nat2->postnat_dest_port = st->key[PF_SK_WIRE]->port[src];
        nat1->postnat_dest_ip = nat2->postnat_src_ip = st->key[PF_SK_WIRE]->addr[dst].v4.s_addr;
        nat1->postnat_dest_port = nat2->postnat_src_port = st->key[PF_SK_WIRE]->port[dst];
        nat1->protocol = nat2->protocol = sk->proto;

        /*
         * Because we have to generate a create and delete event we'll fill out the
         * timestamp and nat_event fields when we transmit. As opposed to doing this
         * work a second time.
        */
}

static void
export_pflow(const struct pf_kstate *st)
{
        struct pflow_softc      *sc = NULL;
        struct pf_state_key     *sk;

        NET_EPOCH_ASSERT();

        /* e.g. if pf_state_key_attach() fails. */
        if (st->key[PF_SK_STACK] == NULL || st->key[PF_SK_WIRE] == NULL)
                return;

        sk = st->key[st->direction == PF_IN ? PF_SK_WIRE : PF_SK_STACK];

        CK_LIST_FOREACH(sc, &V_pflowif_list, sc_next) {
                PFLOW_LOCK(sc);
                switch (sc->sc_version) {
                case PFLOW_PROTO_5:
                        if (sk->af == AF_INET)
                                export_pflow_if(st, sk, sc);
                        break;
                case PFLOW_PROTO_10:
                        if (sk->af == AF_INET || sk->af == AF_INET6)
                                export_pflow_if(st, sk, sc);
                        break;
                default: /* NOTREACHED */
                        break;
                }
                PFLOW_UNLOCK(sc);
        }
}

static int
export_pflow_if(const struct pf_kstate *st, struct pf_state_key *sk,
    struct pflow_softc *sc)
{
        struct pf_kstate         pfs_copy;
        u_int64_t                bytes[2];
        int                      ret = 0;

        if (sc->sc_version == PFLOW_PROTO_10)
                return (pflow_pack_flow_ipfix(st, sk, sc));

        /* PFLOW_PROTO_5 */
        if ((st->bytes[0] < (u_int64_t)PFLOW_MAXBYTES)
            && (st->bytes[1] < (u_int64_t)PFLOW_MAXBYTES))
                return (pflow_pack_flow(st, sk, sc));

        /* flow > PFLOW_MAXBYTES need special handling */
        bcopy(st, &pfs_copy, sizeof(pfs_copy));
        bytes[0] = pfs_copy.bytes[0];
        bytes[1] = pfs_copy.bytes[1];

        while (bytes[0] > PFLOW_MAXBYTES) {
                pfs_copy.bytes[0] = PFLOW_MAXBYTES;
                pfs_copy.bytes[1] = 0;

                if ((ret = pflow_pack_flow(&pfs_copy, sk, sc)) != 0)
                        return (ret);
                if ((bytes[0] - PFLOW_MAXBYTES) > 0)
                        bytes[0] -= PFLOW_MAXBYTES;
        }

        while (bytes[1] > (u_int64_t)PFLOW_MAXBYTES) {
                pfs_copy.bytes[1] = PFLOW_MAXBYTES;
                pfs_copy.bytes[0] = 0;

                if ((ret = pflow_pack_flow(&pfs_copy, sk, sc)) != 0)
                        return (ret);
                if ((bytes[1] - PFLOW_MAXBYTES) > 0)
                        bytes[1] -= PFLOW_MAXBYTES;
        }

        pfs_copy.bytes[0] = bytes[0];
        pfs_copy.bytes[1] = bytes[1];

        return (pflow_pack_flow(&pfs_copy, sk, sc));
}

static int
copy_flow_to_m(struct pflow_flow *flow, struct pflow_softc *sc)
{
        int             ret = 0;

        PFLOW_ASSERT(sc);

        if (sc->sc_mbuf == NULL) {
                if ((sc->sc_mbuf = pflow_get_mbuf(sc, 0)) == NULL)
                        return (ENOBUFS);
        }
        m_copyback(sc->sc_mbuf, PFLOW_HDRLEN +
            (sc->sc_count * sizeof(struct pflow_flow)),
            sizeof(struct pflow_flow), (caddr_t)flow);

        pflowstat_inc(pflow_flows);
        sc->sc_gcounter++;
        sc->sc_count++;

        if (sc->sc_count >= sc->sc_maxcount)
                ret = pflow_sendout_v5(sc);

        return(ret);
}

static int
copy_flow_ipfix_4_to_m(struct pflow_ipfix_flow4 *flow, struct pflow_softc *sc)
{
        int             ret = 0;

        PFLOW_ASSERT(sc);

        if (sc->sc_mbuf == NULL) {
                if ((sc->sc_mbuf =
                    pflow_get_mbuf(sc, PFLOW_IPFIX_TMPL_IPV4_ID)) == NULL) {
                        return (ENOBUFS);
                }
                sc->sc_count4 = 0;
                callout_reset(&sc->sc_tmo, PFLOW_TIMEOUT * hz,
                    pflow_timeout, sc);
        }
        m_copyback(sc->sc_mbuf, PFLOW_SET_HDRLEN +
            (sc->sc_count4 * sizeof(struct pflow_ipfix_flow4)),
            sizeof(struct pflow_ipfix_flow4), (caddr_t)flow);

        pflowstat_inc(pflow_flows);
        sc->sc_gcounter++;
        sc->sc_count4++;

        if (sc->sc_count4 >= sc->sc_maxcount4)
                ret = pflow_sendout_ipfix(sc, PFLOW_INET);
        return(ret);
}

static int
copy_flow_ipfix_6_to_m(struct pflow_ipfix_flow6 *flow, struct pflow_softc *sc)
{
        int             ret = 0;

        PFLOW_ASSERT(sc);

        if (sc->sc_mbuf6 == NULL) {
                if ((sc->sc_mbuf6 =
                    pflow_get_mbuf(sc, PFLOW_IPFIX_TMPL_IPV6_ID)) == NULL) {
                        return (ENOBUFS);
                }
                sc->sc_count6 = 0;
                callout_reset(&sc->sc_tmo6, PFLOW_TIMEOUT * hz,
                    pflow_timeout6, sc);
        }
        m_copyback(sc->sc_mbuf6, PFLOW_SET_HDRLEN +
            (sc->sc_count6 * sizeof(struct pflow_ipfix_flow6)),
            sizeof(struct pflow_ipfix_flow6), (caddr_t)flow);

        pflowstat_inc(pflow_flows);
        sc->sc_gcounter++;
        sc->sc_count6++;

        if (sc->sc_count6 >= sc->sc_maxcount6)
                ret = pflow_sendout_ipfix(sc, PFLOW_INET6);

        return(ret);
}

int
copy_nat_ipfix_4_to_m(struct pflow_ipfix_nat4 *nat, const struct pf_kstate *st,
    struct pflow_softc *sc, uint8_t event, uint64_t timestamp)
{
        int             ret = 0;

        PFLOW_ASSERT(sc);

        if (sc->sc_mbuf_nat4 == NULL) {
                if ((sc->sc_mbuf_nat4 =
                    pflow_get_mbuf(sc, PFLOW_IPFIX_TMPL_NAT44_ID)) == NULL) {
                        return (ENOBUFS);
                }
                sc->sc_count_nat4 = 0;
                callout_reset(&sc->sc_tmo, PFLOW_TIMEOUT * hz,
                    pflow_timeout_nat4, sc);
        }

        nat->nat_event = event;
        nat->timestamp = htobe64(pf_get_time() - (pf_get_uptime() - timestamp));
        m_copyback(sc->sc_mbuf_nat4, PFLOW_SET_HDRLEN +
            (sc->sc_count_nat4 * sizeof(struct pflow_ipfix_nat4)),
            sizeof(struct pflow_ipfix_nat4), (caddr_t)nat);
        sc->sc_count_nat4++;

        pflowstat_inc(pflow_flows);
        sc->sc_gcounter++;

        if (sc->sc_count_nat4 >= sc->sc_maxcount_nat4)
                ret = pflow_sendout_ipfix(sc, PFLOW_NAT4);

        return (ret);
}

static int
pflow_pack_flow(const struct pf_kstate *st, struct pf_state_key *sk,
    struct pflow_softc *sc)
{
        struct pflow_flow        flow1;
        struct pflow_flow        flow2;
        int                      ret = 0;

        bzero(&flow1, sizeof(flow1));
        bzero(&flow2, sizeof(flow2));

        if (st->direction == PF_OUT)
                copy_flow_data(&flow1, &flow2, st, sk, 1, 0);
        else
                copy_flow_data(&flow1, &flow2, st, sk, 0, 1);

        if (st->bytes[0] != 0) /* first flow from state */
                ret = copy_flow_to_m(&flow1, sc);

        if (st->bytes[1] != 0) /* second flow from state */
                ret = copy_flow_to_m(&flow2, sc);

        return (ret);
}

static bool
pflow_is_natd(const struct pf_kstate *st)
{
        /* If ports or addresses are different we've been NAT-ed. */
        return (memcmp(st->key[PF_SK_WIRE], st->key[PF_SK_STACK],
            sizeof(struct pf_addr) * 2 + sizeof(uint16_t) * 2) != 0);
}

static int
pflow_pack_flow_ipfix(const struct pf_kstate *st, struct pf_state_key *sk,
    struct pflow_softc *sc)
{
        struct pflow_ipfix_flow4         flow4_1, flow4_2;
        struct pflow_ipfix_nat4          nat4_1, nat4_2;
        struct pflow_ipfix_flow6         flow6_1, flow6_2;
        int                              ret = 0;
        bool                             nat = false;

        switch (sk->af) {
        case AF_INET:
                bzero(&flow4_1, sizeof(flow4_1));
                bzero(&flow4_2, sizeof(flow4_2));

                nat = pflow_is_natd(st);

                if (st->direction == PF_OUT)
                        copy_flow_ipfix_4_data(&flow4_1, &flow4_2, st, sk, sc,
                            1, 0);
                else
                        copy_flow_ipfix_4_data(&flow4_1, &flow4_2, st, sk, sc,
                            0, 1);

                if (nat)
                        copy_nat_ipfix_4_data(&nat4_1, &nat4_2, st, sk, sc, 1, 0);

                if (st->bytes[0] != 0) /* first flow from state */ {
                        ret = copy_flow_ipfix_4_to_m(&flow4_1, sc);

                        if (ret == 0 && nat) {
                                ret = copy_nat_ipfix_4_to_m(&nat4_1, st, sc,
                                    PFIX_NAT_EVENT_SESSION_CREATE, st->creation);
                                ret |= copy_nat_ipfix_4_to_m(&nat4_1, st, sc,
                                    PFIX_NAT_EVENT_SESSION_DELETE, st->expire);
                        }
                }

                if (st->bytes[1] != 0) /* second flow from state */ {
                        ret = copy_flow_ipfix_4_to_m(&flow4_2, sc);

                        if (ret == 0 && nat) {
                                ret = copy_nat_ipfix_4_to_m(&nat4_2, st, sc,
                                    PFIX_NAT_EVENT_SESSION_CREATE, st->creation);
                                ret |= copy_nat_ipfix_4_to_m(&nat4_2, st, sc,
                                    PFIX_NAT_EVENT_SESSION_DELETE, st->expire);
                        }
                }
                break;
        case AF_INET6:
                bzero(&flow6_1, sizeof(flow6_1));
                bzero(&flow6_2, sizeof(flow6_2));

                if (st->direction == PF_OUT)
                        copy_flow_ipfix_6_data(&flow6_1, &flow6_2, st, sk, sc,
                            1, 0);
                else
                        copy_flow_ipfix_6_data(&flow6_1, &flow6_2, st, sk, sc,
                            0, 1);

                if (st->bytes[0] != 0) /* first flow from state */
                        ret = copy_flow_ipfix_6_to_m(&flow6_1, sc);

                if (st->bytes[1] != 0) /* second flow from state */
                        ret = copy_flow_ipfix_6_to_m(&flow6_2, sc);
                break;
        }
        return (ret);
}

static void
pflow_timeout(void *v)
{
        struct pflow_softc      *sc = v;

        PFLOW_ASSERT(sc);
        CURVNET_SET(sc->sc_vnet);

        switch (sc->sc_version) {
        case PFLOW_PROTO_5:
                pflow_sendout_v5(sc);
                break;
        case PFLOW_PROTO_10:
                pflow_sendout_ipfix(sc, PFLOW_INET);
                break;
        default: /* NOTREACHED */
                panic("Unsupported version %d", sc->sc_version);
                break;
        }

        CURVNET_RESTORE();
}

static void
pflow_timeout6(void *v)
{
        struct pflow_softc      *sc = v;

        PFLOW_ASSERT(sc);

        if (sc->sc_version != PFLOW_PROTO_10)
                return;

        CURVNET_SET(sc->sc_vnet);
        pflow_sendout_ipfix(sc, PFLOW_INET6);
        CURVNET_RESTORE();
}

static void
pflow_timeout_tmpl(void *v)
{
        struct pflow_softc      *sc = v;

        PFLOW_ASSERT(sc);

        if (sc->sc_version != PFLOW_PROTO_10)
                return;

        CURVNET_SET(sc->sc_vnet);
        pflow_sendout_ipfix_tmpl(sc);
        CURVNET_RESTORE();
}

static void
pflow_timeout_nat4(void *v)
{
        struct pflow_softc      *sc = v;

        PFLOW_ASSERT(sc);

        if (sc->sc_version != PFLOW_PROTO_10)
                return;

        CURVNET_SET(sc->sc_vnet);
        pflow_sendout_ipfix(sc, PFLOW_NAT4);
        CURVNET_RESTORE();
}

static void
pflow_flush(struct pflow_softc *sc)
{
        PFLOW_ASSERT(sc);

        switch (sc->sc_version) {
        case PFLOW_PROTO_5:
                pflow_sendout_v5(sc);
                break;
        case PFLOW_PROTO_10:
                pflow_sendout_ipfix(sc, PFLOW_INET);
                pflow_sendout_ipfix(sc, PFLOW_INET6);
                pflow_sendout_ipfix(sc, PFLOW_NAT4);
                break;
        default: /* NOTREACHED */
                break;
        }
}

static int
pflow_sendout_v5(struct pflow_softc *sc)
{
        struct mbuf             *m = sc->sc_mbuf;
        struct pflow_header     *h;
        struct timespec         tv;

        PFLOW_ASSERT(sc);

        if (m == NULL)
                return (0);

        sc->sc_mbuf = NULL;

        pflowstat_inc(pflow_packets);
        h = mtod(m, struct pflow_header *);
        h->count = htons(sc->sc_count);

        /* populate pflow_header */
        h->uptime_ms = htonl(time_uptime * 1000);

        getnanotime(&tv);
        h->time_sec = htonl(tv.tv_sec);                 /* XXX 2038 */
        h->time_nanosec = htonl(tv.tv_nsec);
        if (mbufq_enqueue(&sc->sc_outputqueue, m) == 0)
                swi_sched(sc->sc_swi_cookie, 0);

        return (0);
}

static int
pflow_sendout_ipfix(struct pflow_softc *sc, enum pflow_family_t af)
{
        struct mbuf                     *m;
        struct pflow_v10_header         *h10;
        struct pflow_set_header         *set_hdr;
        u_int32_t                        count;
        int                              set_length;

        PFLOW_ASSERT(sc);

        switch (af) {
        case PFLOW_INET:
                m = sc->sc_mbuf;
                callout_stop(&sc->sc_tmo);
                if (m == NULL)
                        return (0);
                sc->sc_mbuf = NULL;
                count = sc->sc_count4;
                set_length = sizeof(struct pflow_set_header)
                    + sc->sc_count4 * sizeof(struct pflow_ipfix_flow4);
                break;
        case PFLOW_INET6:
                m = sc->sc_mbuf6;
                callout_stop(&sc->sc_tmo6);
                if (m == NULL)
                        return (0);
                sc->sc_mbuf6 = NULL;
                count = sc->sc_count6;
                set_length = sizeof(struct pflow_set_header)
                    + sc->sc_count6 * sizeof(struct pflow_ipfix_flow6);
                break;
        case PFLOW_NAT4:
                m = sc->sc_mbuf_nat4;
                callout_stop(&sc->sc_tmo_nat4);
                if (m == NULL)
                        return (0);
                sc->sc_mbuf_nat4 = NULL;
                count = sc->sc_count_nat4;
                set_length = sizeof(struct pflow_set_header)
                    + sc->sc_count_nat4 * sizeof(struct pflow_ipfix_nat4);
                break;
        default:
                unhandled_af(af);
        }

        pflowstat_inc(pflow_packets);

        set_hdr = mtod(m, struct pflow_set_header *);
        set_hdr->set_length = htons(set_length);

        /* populate pflow_header */
        M_PREPEND(m, sizeof(struct pflow_v10_header), M_NOWAIT);
        if (m == NULL) {
                pflowstat_inc(pflow_onomem);
                return (ENOBUFS);
        }
        h10 = mtod(m, struct pflow_v10_header *);
        h10->version = htons(PFLOW_PROTO_10);
        h10->length = htons(PFLOW_IPFIX_HDRLEN + set_length);
        h10->time_sec = htonl(time_second);             /* XXX 2038 */
        h10->flow_sequence = htonl(sc->sc_sequence);
        sc->sc_sequence += count;
        h10->observation_dom = htonl(sc->sc_observation_dom);
        if (mbufq_enqueue(&sc->sc_outputqueue, m) == 0)
                swi_sched(sc->sc_swi_cookie, 0);

        return (0);
}

static int
pflow_sendout_ipfix_tmpl(struct pflow_softc *sc)
{
        struct mbuf                     *m;
        struct pflow_v10_header         *h10;

        PFLOW_ASSERT(sc);

        m = pflow_get_mbuf(sc, 0);
        if (m == NULL)
                return (0);
        m_copyback(m, 0, sizeof(struct pflow_ipfix_tmpl),
            (caddr_t)&sc->sc_tmpl_ipfix);

        pflowstat_inc(pflow_packets);

        /* populate pflow_header */
        M_PREPEND(m, sizeof(struct pflow_v10_header), M_NOWAIT);
        if (m == NULL) {
                pflowstat_inc(pflow_onomem);
                return (ENOBUFS);
        }
        h10 = mtod(m, struct pflow_v10_header *);
        h10->version = htons(PFLOW_PROTO_10);
        h10->length = htons(PFLOW_IPFIX_HDRLEN + sizeof(struct
            pflow_ipfix_tmpl));
        h10->time_sec = htonl(time_second);             /* XXX 2038 */
        h10->flow_sequence = htonl(sc->sc_sequence);
        h10->observation_dom = htonl(sc->sc_observation_dom);

        callout_reset(&sc->sc_tmo_tmpl, PFLOW_TMPL_TIMEOUT * hz,
            pflow_timeout_tmpl, sc);
        if (mbufq_enqueue(&sc->sc_outputqueue, m) == 0)
                swi_sched(sc->sc_swi_cookie, 0);

        return (0);
}

static int
pflow_sendout_mbuf(struct pflow_softc *sc, struct mbuf *m)
{
        if (sc->so == NULL) {
                m_freem(m);
                return (EINVAL);
        }
        return (sosend(sc->so, sc->sc_flowdst, NULL, m, NULL, 0, curthread));
}

static int
sysctl_pflowstats(SYSCTL_HANDLER_ARGS)
{
        struct pflowstats pflowstats;

        pflowstats.pflow_flows =
            counter_u64_fetch(V_pflowstats.c[pflow_flows]);
        pflowstats.pflow_packets =
            counter_u64_fetch(V_pflowstats.c[pflow_packets]);
        pflowstats.pflow_onomem =
            counter_u64_fetch(V_pflowstats.c[pflow_onomem]);
        pflowstats.pflow_oerrors =
            counter_u64_fetch(V_pflowstats.c[pflow_oerrors]);

        return (sysctl_handle_opaque(oidp, &pflowstats, sizeof(pflowstats), req));
}

static int
pflow_nl_list(struct nlmsghdr *hdr, struct nl_pstate *npt)
{
        struct epoch_tracker     et;
        struct pflow_softc      *sc = NULL;
        struct nl_writer         *nw = npt->nw;
        int                      error = 0;

        hdr->nlmsg_flags |= NLM_F_MULTI;

        NET_EPOCH_ENTER(et);
        CK_LIST_FOREACH(sc, &V_pflowif_list, sc_next) {
                if (!nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) {
                        error = ENOMEM;
                        goto out;
                }

                struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
                ghdr_new->cmd = PFLOWNL_CMD_LIST;
                ghdr_new->version = 0;
                ghdr_new->reserved = 0;

                nlattr_add_u32(nw, PFLOWNL_L_ID, sc->sc_id);

                if (! nlmsg_end(nw)) {
                        error = ENOMEM;
                        goto out;
                }
        }

out:
        NET_EPOCH_EXIT(et);

        if (error != 0)
                nlmsg_abort(nw);

        return (error);
}

static int
pflow_nl_create(struct nlmsghdr *hdr, struct nl_pstate *npt)
{
        struct nl_writer         *nw = npt->nw;
        int                      error = 0;
        int                      unit;

        if (! nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) {
                return (ENOMEM);
        }

        struct genlmsghdr *ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
        ghdr_new->cmd = PFLOWNL_CMD_CREATE;
        ghdr_new->version = 0;
        ghdr_new->reserved = 0;

        unit = alloc_unr(V_pflow_unr);
        if (unit == -1) {
                nlmsg_abort(nw);
                return (ENOMEM);
        }

        error = pflow_create(unit);
        if (error != 0) {
                free_unr(V_pflow_unr, unit);
                nlmsg_abort(nw);
                return (error);
        }

        nlattr_add_s32(nw, PFLOWNL_CREATE_ID, unit);

        if (! nlmsg_end(nw)) {
                pflow_destroy(unit, true);
                return (ENOMEM);
        }

        return (0);
}

struct pflow_parsed_del {
        int id;
};
#define _OUT(_field)    offsetof(struct pflow_parsed_del, _field)
static const struct nlattr_parser nla_p_del[] = {
        { .type = PFLOWNL_DEL_ID, .off = _OUT(id), .cb = nlattr_get_uint32 },
};
#undef _OUT
NL_DECLARE_PARSER(del_parser, struct genlmsghdr, nlf_p_empty, nla_p_del);

static int
pflow_nl_del(struct nlmsghdr *hdr, struct nl_pstate *npt)
{
        struct pflow_parsed_del d = {};
        int error;

        error = nl_parse_nlmsg(hdr, &del_parser, npt, &d);
        if (error != 0)
                return (error);

        error = pflow_destroy(d.id, true);

        return (error);
}

struct pflow_parsed_get {
        int id;
};
#define _OUT(_field)    offsetof(struct pflow_parsed_get, _field)
static const struct nlattr_parser nla_p_get[] = {
        { .type = PFLOWNL_GET_ID, .off = _OUT(id), .cb = nlattr_get_uint32 },
};
#undef _OUT
NL_DECLARE_PARSER(get_parser, struct genlmsghdr, nlf_p_empty, nla_p_get);

static bool
nlattr_add_sockaddr(struct nl_writer *nw, int attr, const struct sockaddr *s)
{
        int off = nlattr_add_nested(nw, attr);
        if (off == 0)
                return (false);

        nlattr_add_u8(nw, PFLOWNL_ADDR_FAMILY, s->sa_family);

        switch (s->sa_family) {
        case AF_INET: {
                const struct sockaddr_in *in = (const struct sockaddr_in *)s;
                nlattr_add_u16(nw, PFLOWNL_ADDR_PORT, in->sin_port);
                nlattr_add_in_addr(nw, PFLOWNL_ADDR_IP, &in->sin_addr);
                break;
        }
        case AF_INET6: {
                const struct sockaddr_in6 *in6 = (const struct sockaddr_in6 *)s;
                nlattr_add_u16(nw, PFLOWNL_ADDR_PORT, in6->sin6_port);
                nlattr_add_in6_addr(nw, PFLOWNL_ADDR_IP6, &in6->sin6_addr);
                break;
        }
        default:
                unhandled_af(s->sa_family);
        }

        nlattr_set_len(nw, off);
        return (true);
}

static int
pflow_nl_get(struct nlmsghdr *hdr, struct nl_pstate *npt)
{
        struct epoch_tracker et;
        struct pflow_parsed_get g = {};
        struct pflow_softc *sc = NULL;
        struct nl_writer *nw = npt->nw;
        struct genlmsghdr *ghdr_new;
        int error;

        error = nl_parse_nlmsg(hdr, &get_parser, npt, &g);
        if (error != 0)
                return (error);

        NET_EPOCH_ENTER(et);
        CK_LIST_FOREACH(sc, &V_pflowif_list, sc_next) {
                if (sc->sc_id == g.id)
                        break;
        }
        if (sc == NULL) {
                error = ENOENT;
                goto out;
        }

        if (! nlmsg_reply(nw, hdr, sizeof(struct genlmsghdr))) {
                nlmsg_abort(nw);
                error = ENOMEM;
                goto out;
        }

        ghdr_new = nlmsg_reserve_object(nw, struct genlmsghdr);
        if (ghdr_new == NULL) {
                nlmsg_abort(nw);
                error = ENOMEM;
                goto out;
        }

        ghdr_new->cmd = PFLOWNL_CMD_GET;
        ghdr_new->version = 0;
        ghdr_new->reserved = 0;

        nlattr_add_u32(nw, PFLOWNL_GET_ID, sc->sc_id);
        nlattr_add_u16(nw, PFLOWNL_GET_VERSION, sc->sc_version);
        if (sc->sc_flowsrc)
                nlattr_add_sockaddr(nw, PFLOWNL_GET_SRC, sc->sc_flowsrc);
        if (sc->sc_flowdst)
                nlattr_add_sockaddr(nw, PFLOWNL_GET_DST, sc->sc_flowdst);
        nlattr_add_u32(nw, PFLOWNL_GET_OBSERVATION_DOMAIN,
            sc->sc_observation_dom);
        nlattr_add_u8(nw, PFLOWNL_GET_SOCKET_STATUS, sc->so != NULL);

        if (! nlmsg_end(nw)) {
                nlmsg_abort(nw);
                error = ENOMEM;
        }

out:
        NET_EPOCH_EXIT(et);

        return (error);
}

struct pflow_sockaddr {
        union {
                struct sockaddr_in in;
                struct sockaddr_in6 in6;
                struct sockaddr_storage storage;
        };
};
static bool
pflow_postparse_sockaddr(void *parsed_args, struct nl_pstate *npt __unused)
{
        struct pflow_sockaddr *s = (struct pflow_sockaddr *)parsed_args;

        if (s->storage.ss_family == AF_INET)
                s->storage.ss_len = sizeof(struct sockaddr_in);
        else if (s->storage.ss_family == AF_INET6)
                s->storage.ss_len = sizeof(struct sockaddr_in6);
        else
                return (false);

        return (true);
}

#define _OUT(_field)    offsetof(struct pflow_sockaddr, _field)
static struct nlattr_parser nla_p_sockaddr[] = {
        { .type = PFLOWNL_ADDR_FAMILY, .off = _OUT(in.sin_family), .cb = nlattr_get_uint8 },
        { .type = PFLOWNL_ADDR_PORT, .off = _OUT(in.sin_port), .cb = nlattr_get_uint16 },
        { .type = PFLOWNL_ADDR_IP, .off = _OUT(in.sin_addr), .cb = nlattr_get_in_addr },
        { .type = PFLOWNL_ADDR_IP6, .off = _OUT(in6.sin6_addr), .cb = nlattr_get_in6_addr },
};
NL_DECLARE_ATTR_PARSER_EXT(addr_parser, nla_p_sockaddr, pflow_postparse_sockaddr);
#undef _OUT

struct pflow_parsed_set {
        int id;
        uint16_t version;
        struct sockaddr_storage src;
        struct sockaddr_storage dst;
        uint32_t observation_dom;
};
#define _OUT(_field)    offsetof(struct pflow_parsed_set, _field)
static const struct nlattr_parser nla_p_set[] = {
        { .type = PFLOWNL_SET_ID, .off = _OUT(id), .cb = nlattr_get_uint32 },
        { .type = PFLOWNL_SET_VERSION, .off = _OUT(version), .cb = nlattr_get_uint16 },
        { .type = PFLOWNL_SET_SRC, .off = _OUT(src), .arg = &addr_parser, .cb = nlattr_get_nested },
        { .type = PFLOWNL_SET_DST, .off = _OUT(dst), .arg = &addr_parser, .cb = nlattr_get_nested },
        { .type = PFLOWNL_SET_OBSERVATION_DOMAIN, .off = _OUT(observation_dom), .cb = nlattr_get_uint32 },
};
#undef _OUT
NL_DECLARE_PARSER(set_parser, struct genlmsghdr, nlf_p_empty, nla_p_set);

static int
pflow_set(struct pflow_softc *sc, const struct pflow_parsed_set *pflowr, struct ucred *cred)
{
        struct thread           *td;
        struct socket           *so;
        int                      error = 0;

        td = curthread;

        PFLOW_ASSERT(sc);

        if (pflowr->version != 0) {
                switch(pflowr->version) {
                case PFLOW_PROTO_5:
                case PFLOW_PROTO_10:
                        break;
                default:
                        return(EINVAL);
                }
        }

        pflow_flush(sc);

        if (pflowr->dst.ss_len != 0) {
                if (sc->sc_flowdst != NULL &&
                    sc->sc_flowdst->sa_family != pflowr->dst.ss_family) {
                        free(sc->sc_flowdst, M_DEVBUF);
                        sc->sc_flowdst = NULL;
                        if (sc->so != NULL) {
                                soclose(sc->so);
                                sc->so = NULL;
                        }
                }

                switch (pflowr->dst.ss_family) {
                case AF_INET:
                        if (sc->sc_flowdst == NULL) {
                                if ((sc->sc_flowdst = malloc(
                                    sizeof(struct sockaddr_in),
                                    M_DEVBUF,  M_NOWAIT)) == NULL)
                                        return (ENOMEM);
                        }
                        memcpy(sc->sc_flowdst, &pflowr->dst,
                            sizeof(struct sockaddr_in));
                        sc->sc_flowdst->sa_len = sizeof(struct
                            sockaddr_in);
                        break;
                case AF_INET6:
                        if (sc->sc_flowdst == NULL) {
                                if ((sc->sc_flowdst = malloc(
                                    sizeof(struct sockaddr_in6),
                                    M_DEVBUF, M_NOWAIT)) == NULL)
                                        return (ENOMEM);
                        }
                        memcpy(sc->sc_flowdst, &pflowr->dst,
                            sizeof(struct sockaddr_in6));
                        sc->sc_flowdst->sa_len = sizeof(struct
                            sockaddr_in6);
                        break;
                default:
                        break;
                }
        }

        if (pflowr->src.ss_len != 0) {
                if (sc->sc_flowsrc != NULL)
                        free(sc->sc_flowsrc, M_DEVBUF);
                sc->sc_flowsrc = NULL;
                if (sc->so != NULL) {
                        soclose(sc->so);
                        sc->so = NULL;
                }
                switch(pflowr->src.ss_family) {
                case AF_INET:
                        if ((sc->sc_flowsrc = malloc(
                            sizeof(struct sockaddr_in),
                            M_DEVBUF, M_NOWAIT)) == NULL)
                                return (ENOMEM);
                        memcpy(sc->sc_flowsrc, &pflowr->src,
                            sizeof(struct sockaddr_in));
                        sc->sc_flowsrc->sa_len = sizeof(struct
                            sockaddr_in);
                        break;
                case AF_INET6:
                        if ((sc->sc_flowsrc = malloc(
                            sizeof(struct sockaddr_in6),
                            M_DEVBUF, M_NOWAIT)) == NULL)
                                return (ENOMEM);
                        memcpy(sc->sc_flowsrc, &pflowr->src,
                            sizeof(struct sockaddr_in6));
                        sc->sc_flowsrc->sa_len = sizeof(struct
                            sockaddr_in6);
                        break;
                default:
                        break;
                }
        }

        if (sc->so == NULL) {
                if (pflowvalidsockaddr(sc->sc_flowdst, 0)) {
                        error = socreate(sc->sc_flowdst->sa_family,
                            &so, SOCK_DGRAM, IPPROTO_UDP, cred, td);
                        if (error)
                                return (error);
                        if (pflowvalidsockaddr(sc->sc_flowsrc, 1)) {
                                error = sobind(so, sc->sc_flowsrc, td);
                                if (error) {
                                        soclose(so);
                                        return (error);
                                }
                        }
                        sc->so = so;
                }
        } else if (!pflowvalidsockaddr(sc->sc_flowdst, 0)) {
                soclose(sc->so);
                sc->so = NULL;
        }

        if (pflowr->observation_dom != 0)
                sc->sc_observation_dom = pflowr->observation_dom;

        /* error check is above */
        if (pflowr->version != 0)
                sc->sc_version = pflowr->version;

        pflow_setmtu(sc, ETHERMTU);

        switch (sc->sc_version) {
        case PFLOW_PROTO_5:
                callout_stop(&sc->sc_tmo6);
                callout_stop(&sc->sc_tmo_tmpl);
                break;
        case PFLOW_PROTO_10:
                callout_reset(&sc->sc_tmo_tmpl, PFLOW_TMPL_TIMEOUT * hz,
                    pflow_timeout_tmpl, sc);
                break;
        default: /* NOTREACHED */
                break;
        }

        return (0);
}

static int
pflow_nl_set(struct nlmsghdr *hdr, struct nl_pstate *npt)
{
        struct epoch_tracker et;
        struct pflow_parsed_set s = {};
        struct pflow_softc *sc = NULL;
        int error;

        error = nl_parse_nlmsg(hdr, &set_parser, npt, &s);
        if (error != 0)
                return (error);

        NET_EPOCH_ENTER(et);
        CK_LIST_FOREACH(sc, &V_pflowif_list, sc_next) {
                if (sc->sc_id == s.id)
                        break;
        }
        if (sc == NULL) {
                error = ENOENT;
                goto out;
        }

        PFLOW_LOCK(sc);
        error = pflow_set(sc, &s, nlp_get_cred(npt->nlp));
        PFLOW_UNLOCK(sc);

out:
        NET_EPOCH_EXIT(et);
        return (error);
}

static const struct genl_cmd pflow_cmds[] = {
        {
                .cmd_num = PFLOWNL_CMD_LIST,
                .cmd_name = "LIST",
                .cmd_cb = pflow_nl_list,
                .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
                .cmd_priv = PRIV_NETINET_PF,
        },
        {
                .cmd_num = PFLOWNL_CMD_CREATE,
                .cmd_name = "CREATE",
                .cmd_cb = pflow_nl_create,
                .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
                .cmd_priv = PRIV_NETINET_PF,
        },
        {
                .cmd_num = PFLOWNL_CMD_DEL,
                .cmd_name = "DEL",
                .cmd_cb = pflow_nl_del,
                .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
                .cmd_priv = PRIV_NETINET_PF,
        },
        {
                .cmd_num = PFLOWNL_CMD_GET,
                .cmd_name = "GET",
                .cmd_cb = pflow_nl_get,
                .cmd_flags = GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
                .cmd_priv = PRIV_NETINET_PF,
        },
        {
                .cmd_num = PFLOWNL_CMD_SET,
                .cmd_name = "SET",
                .cmd_cb = pflow_nl_set,
                .cmd_flags = GENL_CMD_CAP_DO | GENL_CMD_CAP_DUMP | GENL_CMD_CAP_HASPOL,
                .cmd_priv = PRIV_NETINET_PF,
        },
};

static const struct nlhdr_parser *all_parsers[] = {
        &del_parser,
        &get_parser,
        &set_parser,
};

static unsigned         pflow_do_osd_jail_slot;

static uint16_t family_id;
static int
pflow_init(void)
{
        bool ret;

        NL_VERIFY_PARSERS(all_parsers);

        static osd_method_t methods[PR_MAXMETHOD] = {
                [PR_METHOD_REMOVE] = pflow_jail_remove,
        };
        pflow_do_osd_jail_slot = osd_jail_register(NULL, methods);

        family_id = genl_register_family(PFLOWNL_FAMILY_NAME, 0, 2,
            PFLOWNL_CMD_MAX);
        MPASS(family_id != 0);
        ret = genl_register_cmds(family_id, pflow_cmds, nitems(pflow_cmds));

        return (ret ? 0 : ENODEV);
}

static void
pflow_uninit(void)
{
        osd_jail_deregister(pflow_do_osd_jail_slot);
        genl_unregister_family(family_id);
}

static int
pflow_modevent(module_t mod, int type, void *data)
{
        int error = 0;

        switch (type) {
        case MOD_LOAD:
                error = pflow_init();
                break;
        case MOD_UNLOAD:
                pflow_uninit();
                break;
        default:
                error = EINVAL;
                break;
        }

        return (error);
}

static moduledata_t pflow_mod = {
        pflowname,
        pflow_modevent,
        0
};

DECLARE_MODULE(pflow, pflow_mod, SI_SUB_PROTO_FIREWALL, SI_ORDER_ANY);
MODULE_VERSION(pflow, 1);
MODULE_DEPEND(pflow, pf, PF_MODVER, PF_MODVER, PF_MODVER);