/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2010-2011 Alexander V. Chernikov <melifaro@ipfw.ru>
 * Copyright (c) 2004-2005 Gleb Smirnoff <glebius@FreeBSD.org>
 * Copyright (c) 2001-2003 Roman V. Palagin <romanp@unshadow.net>
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 *
 * $SourceForge: netflow.c,v 1.41 2004/09/05 11:41:10 glebius Exp $
 */

#include <sys/cdefs.h>
#include "opt_inet.h"
#include "opt_inet6.h"
#include <sys/param.h>
#include <sys/bitstring.h>
#include <sys/systm.h>
#include <sys/counter.h>
#include <sys/kernel.h>
#include <sys/ktr.h>
#include <sys/limits.h>
#include <sys/mbuf.h>
#include <sys/syslog.h>
#include <sys/socket.h>
#include <vm/uma.h>

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_var.h>
#include <net/if_private.h>
#include <net/route.h>
#include <net/route/nhop.h>
#include <net/route/route_ctl.h>
#include <net/ethernet.h>
#include <netinet/in.h>
#include <netinet/in_fib.h>
#include <netinet/in_systm.h>
#include <netinet/ip.h>
#include <netinet/ip6.h>
#include <netinet/tcp.h>
#include <netinet/udp.h>

#include <netinet6/in6_fib.h>

#include <netgraph/ng_message.h>
#include <netgraph/netgraph.h>

#include <netgraph/netflow/netflow.h>
#include <netgraph/netflow/netflow_v9.h>
#include <netgraph/netflow/ng_netflow.h>

#define NBUCKETS        (65536)         /* must be power of 2 */

/* This hash is for TCP or UDP packets. */
#define FULL_HASH(addr1, addr2, port1, port2)   \
        (((addr1 ^ (addr1 >> 16) ^              \
        htons(addr2 ^ (addr2 >> 16))) ^         \
        port1 ^ htons(port2)) &                 \
        (NBUCKETS - 1))

/* This hash is for all other IP packets. */
#define ADDR_HASH(addr1, addr2)                 \
        ((addr1 ^ (addr1 >> 16) ^               \
        htons(addr2 ^ (addr2 >> 16))) &         \
        (NBUCKETS - 1))

/* Macros to shorten logical constructions */
/* XXX: priv must exist in namespace */
#define INACTIVE(fle)   (time_uptime - fle->f.last > priv->nfinfo_inact_t)
#define AGED(fle)       (time_uptime - fle->f.first > priv->nfinfo_act_t)
#define ISFREE(fle)     (fle->f.packets == 0)

/*
 * 4 is a magical number: statistically number of 4-packet flows is
 * bigger than 5,6,7...-packet flows by an order of magnitude. Most UDP/ICMP
 * scans are 1 packet (~ 90% of flow cache). TCP scans are 2-packet in case
 * of reachable host and 4-packet otherwise.
 */
#define SMALL(fle)      (fle->f.packets <= 4)

MALLOC_DEFINE(M_NETFLOW_HASH, "netflow_hash", "NetFlow hash");

static int export_add(item_p, struct flow_entry *);
static int export_send(priv_p, fib_export_p, item_p, int);

#ifdef INET
static int hash_insert(priv_p, struct flow_hash_entry *, struct flow_rec *,
    int, uint8_t, uint16_t);
#endif
#ifdef INET6
static int hash6_insert(priv_p, struct flow_hash_entry *, struct flow6_rec *,
    int, uint8_t, uint16_t);
#endif

static void expire_flow(priv_p, fib_export_p, struct flow_entry *, int);

#ifdef INET
/*
 * Generate hash for a given flow record.
 *
 * FIB is not used here, because:
 * most VRFS will carry public IPv4 addresses which are unique even
 * without FIB private addresses can overlap, but this is worked out
 * via flow_rec bcmp() containing fib id. In IPv6 world addresses are
 * all globally unique (it's not fully true, there is FC00::/7 for example,
 * but chances of address overlap are MUCH smaller)
 */
static inline uint32_t
ip_hash(struct flow_rec *r)
{

        switch (r->r_ip_p) {
        case IPPROTO_TCP:
        case IPPROTO_UDP:
                return FULL_HASH(r->r_src.s_addr, r->r_dst.s_addr,
                    r->r_sport, r->r_dport);
        default:
                return ADDR_HASH(r->r_src.s_addr, r->r_dst.s_addr);
        }
}
#endif

#ifdef INET6
/* Generate hash for a given flow6 record. Use lower 4 octets from v6 addresses */
static inline uint32_t
ip6_hash(struct flow6_rec *r)
{

        switch (r->r_ip_p) {
        case IPPROTO_TCP:
        case IPPROTO_UDP:
                return FULL_HASH(r->src.r_src6.__u6_addr.__u6_addr32[3],
                    r->dst.r_dst6.__u6_addr.__u6_addr32[3], r->r_sport,
                    r->r_dport);
        default:
                return ADDR_HASH(r->src.r_src6.__u6_addr.__u6_addr32[3],
                    r->dst.r_dst6.__u6_addr.__u6_addr32[3]);
        }
}

#endif

/*
 * Detach export datagram from priv, if there is any.
 * If there is no, allocate a new one.
 */
static item_p
get_export_dgram(priv_p priv, fib_export_p fe)
{
        item_p  item = NULL;

        mtx_lock(&fe->export_mtx);
        if (fe->exp.item != NULL) {
                item = fe->exp.item;
                fe->exp.item = NULL;
        }
        mtx_unlock(&fe->export_mtx);

        if (item == NULL) {
                struct netflow_v5_export_dgram *dgram;
                struct mbuf *m;

                m = m_getcl(M_NOWAIT, MT_DATA, M_PKTHDR);
                if (m == NULL)
                        return (NULL);
                item = ng_package_data(m, NG_NOFLAGS);
                if (item == NULL)
                        return (NULL);
                dgram = mtod(m, struct netflow_v5_export_dgram *);
                dgram->header.count = 0;
                dgram->header.version = htons(NETFLOW_V5);
                dgram->header.pad = 0;
        }

        return (item);
}

/*
 * Re-attach incomplete datagram back to priv.
 * If there is already another one, then send incomplete. */
static void
return_export_dgram(priv_p priv, fib_export_p fe, item_p item, int flags)
{

        /*
         * It may happen on SMP, that some thread has already
         * put its item there, in this case we bail out and
         * send what we have to collector.
         */
        mtx_lock(&fe->export_mtx);
        if (fe->exp.item == NULL) {
                fe->exp.item = item;
                mtx_unlock(&fe->export_mtx);
        } else {
                mtx_unlock(&fe->export_mtx);
                export_send(priv, fe, item, flags);
        }
}

/*
 * The flow is over. Call export_add() and free it. If datagram is
 * full, then call export_send().
 */
static void
expire_flow(priv_p priv, fib_export_p fe, struct flow_entry *fle, int flags)
{
        struct netflow_export_item exp;
        uint16_t version = fle->f.version;

        if ((priv->export != NULL) && (version == IPVERSION)) {
                exp.item = get_export_dgram(priv, fe);
                if (exp.item == NULL) {
                        priv->nfinfo_export_failed++;
                        if (priv->export9 != NULL)
                                priv->nfinfo_export9_failed++;
                        /* fle definitely contains IPv4 flow. */
                        uma_zfree_arg(priv->zone, fle, priv);
                        return;
                }

                if (export_add(exp.item, fle) > 0)
                        export_send(priv, fe, exp.item, flags);
                else
                        return_export_dgram(priv, fe, exp.item, NG_QUEUE);
        }

        if (priv->export9 != NULL) {
                exp.item9 = get_export9_dgram(priv, fe, &exp.item9_opt);
                if (exp.item9 == NULL) {
                        priv->nfinfo_export9_failed++;
                        if (version == IPVERSION)
                                uma_zfree_arg(priv->zone, fle, priv);
#ifdef INET6
                        else if (version == IP6VERSION)
                                uma_zfree_arg(priv->zone6, fle, priv);
#endif
                        else
                                panic("ng_netflow: Unknown IP proto: %d",
                                    version);
                        return;
                }

                if (export9_add(exp.item9, exp.item9_opt, fle) > 0)
                        export9_send(priv, fe, exp.item9, exp.item9_opt, flags);
                else
                        return_export9_dgram(priv, fe, exp.item9,
                            exp.item9_opt, NG_QUEUE);
        }

        if (version == IPVERSION)
                uma_zfree_arg(priv->zone, fle, priv);
#ifdef INET6
        else if (version == IP6VERSION)
                uma_zfree_arg(priv->zone6, fle, priv);
#endif
}

/* Get a snapshot of node statistics */
void
ng_netflow_copyinfo(priv_p priv, struct ng_netflow_info *i)
{

        i->nfinfo_bytes = counter_u64_fetch(priv->nfinfo_bytes);
        i->nfinfo_packets = counter_u64_fetch(priv->nfinfo_packets);
        i->nfinfo_bytes6 = counter_u64_fetch(priv->nfinfo_bytes6);
        i->nfinfo_packets6 = counter_u64_fetch(priv->nfinfo_packets6);
        i->nfinfo_sbytes = counter_u64_fetch(priv->nfinfo_sbytes);
        i->nfinfo_spackets = counter_u64_fetch(priv->nfinfo_spackets);
        i->nfinfo_sbytes6 = counter_u64_fetch(priv->nfinfo_sbytes6);
        i->nfinfo_spackets6 = counter_u64_fetch(priv->nfinfo_spackets6);
        i->nfinfo_act_exp = counter_u64_fetch(priv->nfinfo_act_exp);
        i->nfinfo_inact_exp = counter_u64_fetch(priv->nfinfo_inact_exp);

        i->nfinfo_used = uma_zone_get_cur(priv->zone);
#ifdef INET6
        i->nfinfo_used6 = uma_zone_get_cur(priv->zone6);
#endif

        i->nfinfo_alloc_failed = priv->nfinfo_alloc_failed;
        i->nfinfo_export_failed = priv->nfinfo_export_failed;
        i->nfinfo_export9_failed = priv->nfinfo_export9_failed;
        i->nfinfo_realloc_mbuf = priv->nfinfo_realloc_mbuf;
        i->nfinfo_alloc_fibs = priv->nfinfo_alloc_fibs;
        i->nfinfo_inact_t = priv->nfinfo_inact_t;
        i->nfinfo_act_t = priv->nfinfo_act_t;
}

/*
 * Insert a record into defined slot.
 *
 * First we get for us a free flow entry, then fill in all
 * possible fields in it.
 *
 * TODO: consider dropping hash mutex while filling in datagram,
 * as this was done in previous version. Need to test & profile
 * to be sure.
 */
#ifdef INET
static int
hash_insert(priv_p priv, struct flow_hash_entry *hsh, struct flow_rec *r,
        int plen, uint8_t flags, uint16_t tcp_flags)
{
        struct flow_entry *fle;

        mtx_assert(&hsh->mtx, MA_OWNED);

        fle = uma_zalloc_arg(priv->zone, priv, M_NOWAIT);
        if (fle == NULL) {
                priv->nfinfo_alloc_failed++;
                return (ENOMEM);
        }

        /*
         * Now fle is totally ours. It is detached from all lists,
         * we can safely edit it.
         */
        fle->f.version = IPVERSION;
        bcopy(r, &fle->f.r, sizeof(struct flow_rec));
        fle->f.bytes = plen;
        fle->f.packets = 1;
        fle->f.tcp_flags = tcp_flags;

        fle->f.first = fle->f.last = time_uptime;

        /*
         * First we do route table lookup on destination address. So we can
         * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases.
         */
        if ((flags & NG_NETFLOW_CONF_NODSTLOOKUP) == 0) {
                struct rtentry *rt;
                struct route_nhop_data rnd;

                rt = fib4_lookup_rt(r->fib, fle->f.r.r_dst, 0, NHR_NONE, &rnd);
                if (rt != NULL) {
                        struct in_addr addr;
                        uint32_t scopeid;
                        struct nhop_object *nh = nhop_select_func(rnd.rnd_nhop, 0);
                        int plen;

                        rt_get_inet_prefix_plen(rt, &addr, &plen, &scopeid);
                        fle->f.fle_o_ifx = nh->nh_ifp->if_index;
                        if (nh->gw_sa.sa_family == AF_INET)
                                fle->f.next_hop = nh->gw4_sa.sin_addr;
                        /*
                         * XXX we're leaving an empty gateway here for
                         * IPv6 nexthops.
                         */
                        fle->f.dst_mask = plen;
                }
        }

        /* Do route lookup on source address, to fill in src_mask. */
        if ((flags & NG_NETFLOW_CONF_NOSRCLOOKUP) == 0) {
                struct rtentry *rt;
                struct route_nhop_data rnd;

                rt = fib4_lookup_rt(r->fib, fle->f.r.r_src, 0, NHR_NONE, &rnd);
                if (rt != NULL) {
                        struct in_addr addr;
                        uint32_t scopeid;
                        int plen;

                        rt_get_inet_prefix_plen(rt, &addr, &plen, &scopeid);
                        fle->f.src_mask = plen;
                }
        }

        /* Push new flow at the and of hash. */
        TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);

        return (0);
}
#endif

#ifdef INET6
static int
hash6_insert(priv_p priv, struct flow_hash_entry *hsh6, struct flow6_rec *r,
        int plen, uint8_t flags, uint16_t tcp_flags)
{
        struct flow6_entry *fle6;

        mtx_assert(&hsh6->mtx, MA_OWNED);

        fle6 = uma_zalloc_arg(priv->zone6, priv, M_NOWAIT);
        if (fle6 == NULL) {
                priv->nfinfo_alloc_failed++;
                return (ENOMEM);
        }

        /*
         * Now fle is totally ours. It is detached from all lists,
         * we can safely edit it.
         */

        fle6->f.version = IP6VERSION;
        bcopy(r, &fle6->f.r, sizeof(struct flow6_rec));
        fle6->f.bytes = plen;
        fle6->f.packets = 1;
        fle6->f.tcp_flags = tcp_flags;

        fle6->f.first = fle6->f.last = time_uptime;

        /*
         * First we do route table lookup on destination address. So we can
         * fill in out_ifx, dst_mask, nexthop, and dst_as in future releases.
         */
        if ((flags & NG_NETFLOW_CONF_NODSTLOOKUP) == 0) {
                struct rtentry *rt;
                struct route_nhop_data rnd;

                rt = fib6_lookup_rt(r->fib, &fle6->f.r.dst.r_dst6, 0, NHR_NONE, &rnd);
                if (rt != NULL) {
                        struct in6_addr addr;
                        uint32_t scopeid;
                        struct nhop_object *nh = nhop_select_func(rnd.rnd_nhop, 0);
                        int plen;

                        rt_get_inet6_prefix_plen(rt, &addr, &plen, &scopeid);
                        fle6->f.fle_o_ifx = nh->nh_ifp->if_index;
                        if (nh->gw_sa.sa_family == AF_INET6)
                                fle6->f.n.next_hop6 = nh->gw6_sa.sin6_addr;
                        fle6->f.dst_mask = plen;
                }
        }

        if ((flags & NG_NETFLOW_CONF_NOSRCLOOKUP) == 0) {
                /* Do route lookup on source address, to fill in src_mask. */
                struct rtentry *rt;
                struct route_nhop_data rnd;

                rt = fib6_lookup_rt(r->fib, &fle6->f.r.src.r_src6, 0, NHR_NONE, &rnd);
                if (rt != NULL) {
                        struct in6_addr addr;
                        uint32_t scopeid;
                        int plen;

                        rt_get_inet6_prefix_plen(rt, &addr, &plen, &scopeid);
                        fle6->f.src_mask = plen;
                }
        }

        /* Push new flow at the and of hash. */
        TAILQ_INSERT_TAIL(&hsh6->head, (struct flow_entry *)fle6, fle_hash);

        return (0);
}
#endif

/*
 * Non-static functions called from ng_netflow.c
 */

/* Allocate memory and set up flow cache */
void
ng_netflow_cache_init(priv_p priv)
{
        struct flow_hash_entry *hsh;
        int i;

        /* Initialize cache UMA zone. */
        priv->zone = uma_zcreate("NetFlow IPv4 cache",
            sizeof(struct flow_entry), NULL, NULL, NULL, NULL,
            UMA_ALIGN_CACHE, 0);
        uma_zone_set_max(priv->zone, CACHESIZE);
#ifdef INET6    
        priv->zone6 = uma_zcreate("NetFlow IPv6 cache",
            sizeof(struct flow6_entry), NULL, NULL, NULL, NULL,
            UMA_ALIGN_CACHE, 0);
        uma_zone_set_max(priv->zone6, CACHESIZE);
#endif  

        /* Allocate hash. */
        priv->hash = malloc(NBUCKETS * sizeof(struct flow_hash_entry),
            M_NETFLOW_HASH, M_WAITOK | M_ZERO);

        /* Initialize hash. */
        for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++) {
                mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF);
                TAILQ_INIT(&hsh->head);
        }

#ifdef INET6
        /* Allocate hash. */
        priv->hash6 = malloc(NBUCKETS * sizeof(struct flow_hash_entry),
            M_NETFLOW_HASH, M_WAITOK | M_ZERO);

        /* Initialize hash. */
        for (i = 0, hsh = priv->hash6; i < NBUCKETS; i++, hsh++) {
                mtx_init(&hsh->mtx, "hash mutex", NULL, MTX_DEF);
                TAILQ_INIT(&hsh->head);
        }
#endif

        priv->nfinfo_bytes = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_packets = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_bytes6 = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_packets6 = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_sbytes = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_spackets = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_sbytes6 = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_spackets6 = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_act_exp = counter_u64_alloc(M_WAITOK);
        priv->nfinfo_inact_exp = counter_u64_alloc(M_WAITOK);

        ng_netflow_v9_cache_init(priv);
        CTR0(KTR_NET, "ng_netflow startup()");
}

/* Initialize new FIB table for v5 and v9 */
int
ng_netflow_fib_init(priv_p priv, int fib)
{
        fib_export_p    fe = priv_to_fib(priv, fib);

        CTR1(KTR_NET, "ng_netflow(): fib init: %d", fib);

        if (fe != NULL)
                return (0);

        if ((fe = malloc(sizeof(struct fib_export), M_NETGRAPH,
            M_NOWAIT | M_ZERO)) == NULL)
                return (ENOMEM);

        mtx_init(&fe->export_mtx, "export dgram lock", NULL, MTX_DEF);
        mtx_init(&fe->export9_mtx, "export9 dgram lock", NULL, MTX_DEF);
        fe->fib = fib;
        fe->domain_id = fib;

        if (atomic_cmpset_ptr((volatile uintptr_t *)&priv->fib_data[fib],
            (uintptr_t)NULL, (uintptr_t)fe) == 0) {
                /* FIB already set up by other ISR */
                CTR3(KTR_NET, "ng_netflow(): fib init: %d setup %p but got %p",
                    fib, fe, priv_to_fib(priv, fib));
                mtx_destroy(&fe->export_mtx);
                mtx_destroy(&fe->export9_mtx);
                free(fe, M_NETGRAPH);
        } else {
                /* Increase counter for statistics */
                CTR3(KTR_NET, "ng_netflow(): fib %d setup to %p (%p)",
                    fib, fe, priv_to_fib(priv, fib));
                priv->nfinfo_alloc_fibs++;
        }

        return (0);
}

/* Free all flow cache memory. Called from node close method. */
void
ng_netflow_cache_flush(priv_p priv)
{
        struct flow_entry       *fle, *fle1;
        struct flow_hash_entry  *hsh;
        struct netflow_export_item exp;
        fib_export_p fe;
        int i;

        bzero(&exp, sizeof(exp));

        /*
         * We are going to free probably billable data.
         * Expire everything before freeing it.
         * No locking is required since callout is already drained.
         */
        for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++)
                TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        fe = priv_to_fib(priv, fle->f.r.fib);
                        expire_flow(priv, fe, fle, NG_QUEUE);
                }
#ifdef INET6
        for (hsh = priv->hash6, i = 0; i < NBUCKETS; hsh++, i++)
                TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        fe = priv_to_fib(priv, fle->f.r.fib);
                        expire_flow(priv, fe, fle, NG_QUEUE);
                }
#endif

        uma_zdestroy(priv->zone);
        /* Destroy hash mutexes. */
        for (i = 0, hsh = priv->hash; i < NBUCKETS; i++, hsh++)
                mtx_destroy(&hsh->mtx);

        /* Free hash memory. */
        if (priv->hash != NULL)
                free(priv->hash, M_NETFLOW_HASH);
#ifdef INET6
        uma_zdestroy(priv->zone6);
        /* Destroy hash mutexes. */
        for (i = 0, hsh = priv->hash6; i < NBUCKETS; i++, hsh++)
                mtx_destroy(&hsh->mtx);

        /* Free hash memory. */
        if (priv->hash6 != NULL)
                free(priv->hash6, M_NETFLOW_HASH);
#endif

        for (i = 0; i < priv->maxfibs; i++) {
                if ((fe = priv_to_fib(priv, i)) == NULL)
                        continue;

                if (fe->exp.item != NULL)
                        export_send(priv, fe, fe->exp.item, NG_QUEUE);

                if (fe->exp.item9 != NULL)
                        export9_send(priv, fe, fe->exp.item9,
                            fe->exp.item9_opt, NG_QUEUE);

                mtx_destroy(&fe->export_mtx);
                mtx_destroy(&fe->export9_mtx);
                free(fe, M_NETGRAPH);
        }

        counter_u64_free(priv->nfinfo_bytes);
        counter_u64_free(priv->nfinfo_packets);
        counter_u64_free(priv->nfinfo_bytes6);
        counter_u64_free(priv->nfinfo_packets6);
        counter_u64_free(priv->nfinfo_sbytes);
        counter_u64_free(priv->nfinfo_spackets);
        counter_u64_free(priv->nfinfo_sbytes6);
        counter_u64_free(priv->nfinfo_spackets6);
        counter_u64_free(priv->nfinfo_act_exp);
        counter_u64_free(priv->nfinfo_inact_exp);

        ng_netflow_v9_cache_flush(priv);
}

#ifdef INET
/* Insert packet from into flow cache. */
int
ng_netflow_flow_add(priv_p priv, fib_export_p fe, struct ip *ip,
    caddr_t upper_ptr, uint8_t upper_proto, uint8_t flags,
    unsigned int src_if_index)
{
        struct flow_entry       *fle, *fle1;
        struct flow_hash_entry  *hsh;
        struct flow_rec         r;
        int                     hlen, plen;
        int                     error = 0;
        uint16_t                tcp_flags = 0;

        bzero(&r, sizeof(r));

        if (ip->ip_v != IPVERSION)
                return (EINVAL);

        hlen = ip->ip_hl << 2;
        if (hlen < sizeof(struct ip))
                return (EINVAL);

        /* Assume L4 template by default */
        r.flow_type = NETFLOW_V9_FLOW_V4_L4;

        r.r_src = ip->ip_src;
        r.r_dst = ip->ip_dst;
        r.fib = fe->fib;

        plen = ntohs(ip->ip_len);

        r.r_ip_p = ip->ip_p;
        r.r_tos = ip->ip_tos;

        r.r_i_ifx = src_if_index;

        /*
         * XXX NOTE: only first fragment of fragmented TCP, UDP and
         * ICMP packet will be recorded with proper s_port and d_port.
         * Following fragments will be recorded simply as IP packet with
         * ip_proto = ip->ip_p and s_port, d_port set to zero.
         * I know, it looks like bug. But I don't want to re-implement
         * ip packet assebmling here. Anyway, (in)famous trafd works this way -
         * and nobody complains yet :)
         */
        if ((ip->ip_off & htons(IP_OFFMASK)) == 0)
                switch(r.r_ip_p) {
                case IPPROTO_TCP:
                    {
                        struct tcphdr *tcp;

                        tcp = (struct tcphdr *)((caddr_t )ip + hlen);
                        r.r_sport = tcp->th_sport;
                        r.r_dport = tcp->th_dport;
                        tcp_flags = tcp_get_flags(tcp);
                        break;
                    }
                case IPPROTO_UDP:
                        r.r_ports = *(uint32_t *)((caddr_t )ip + hlen);
                        break;
                }

        counter_u64_add(priv->nfinfo_packets, 1);
        counter_u64_add(priv->nfinfo_bytes, plen);

        /* Find hash slot. */
        hsh = &priv->hash[ip_hash(&r)];

        mtx_lock(&hsh->mtx);

        /*
         * Go through hash and find our entry. If we encounter an
         * entry, that should be expired, purge it. We do a reverse
         * search since most active entries are first, and most
         * searches are done on most active entries.
         */
        TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) {
                if (bcmp(&r, &fle->f.r, sizeof(struct flow_rec)) == 0)
                        break;
                if ((INACTIVE(fle) && SMALL(fle)) || AGED(fle)) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        expire_flow(priv, priv_to_fib(priv, fle->f.r.fib),
                            fle, NG_QUEUE);
                        counter_u64_add(priv->nfinfo_act_exp, 1);
                }
        }

        if (fle) {                      /* An existent entry. */

                fle->f.bytes += plen;
                fle->f.packets ++;
                fle->f.tcp_flags |= tcp_flags;
                fle->f.last = time_uptime;

                /*
                 * We have the following reasons to expire flow in active way:
                 * - it hit active timeout
                 * - a TCP connection closed
                 * - it is going to overflow counter
                 */
                if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle) ||
                    (fle->f.bytes >= (CNTR_MAX - IF_MAXMTU)) ) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        expire_flow(priv, priv_to_fib(priv, fle->f.r.fib),
                            fle, NG_QUEUE);
                        counter_u64_add(priv->nfinfo_act_exp, 1);
                } else {
                        /*
                         * It is the newest, move it to the tail,
                         * if it isn't there already. Next search will
                         * locate it quicker.
                         */
                        if (fle != TAILQ_LAST(&hsh->head, fhead)) {
                                TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                                TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
                        }
                }
        } else                          /* A new flow entry. */
                error = hash_insert(priv, hsh, &r, plen, flags, tcp_flags);

        mtx_unlock(&hsh->mtx);

        return (error);
}
#endif

#ifdef INET6
/* Insert IPv6 packet from into flow cache. */
int
ng_netflow_flow6_add(priv_p priv, fib_export_p fe, struct ip6_hdr *ip6,
    caddr_t upper_ptr, uint8_t upper_proto, uint8_t flags,
    unsigned int src_if_index)
{
        struct flow_entry       *fle = NULL, *fle1;
        struct flow6_entry      *fle6;
        struct flow_hash_entry  *hsh;
        struct flow6_rec        r;
        int                     plen;
        int                     error = 0;
        uint16_t                tcp_flags = 0;

        /* check version */
        if ((ip6->ip6_vfc & IPV6_VERSION_MASK) != IPV6_VERSION)
                return (EINVAL);

        bzero(&r, sizeof(r));

        r.src.r_src6 = ip6->ip6_src;
        r.dst.r_dst6 = ip6->ip6_dst;
        r.fib = fe->fib;

        /* Assume L4 template by default */
        r.flow_type = NETFLOW_V9_FLOW_V6_L4;

        plen = ntohs(ip6->ip6_plen) + sizeof(struct ip6_hdr);

#if 0
        /* XXX: set DSCP/CoS value */
        r.r_tos = ip->ip_tos;
#endif
        if ((flags & NG_NETFLOW_IS_FRAG) == 0) {
                switch(upper_proto) {
                case IPPROTO_TCP:
                    {
                        struct tcphdr *tcp;

                        tcp = (struct tcphdr *)upper_ptr;
                        r.r_ports = *(uint32_t *)upper_ptr;
                        tcp_flags = tcp_get_flags(tcp);
                        break;
                    }
                case IPPROTO_UDP:
                case IPPROTO_SCTP:
                        r.r_ports = *(uint32_t *)upper_ptr;
                        break;
                }
        }       

        r.r_ip_p = upper_proto;
        r.r_i_ifx = src_if_index;

        counter_u64_add(priv->nfinfo_packets6, 1);
        counter_u64_add(priv->nfinfo_bytes6, plen);

        /* Find hash slot. */
        hsh = &priv->hash6[ip6_hash(&r)];

        mtx_lock(&hsh->mtx);

        /*
         * Go through hash and find our entry. If we encounter an
         * entry, that should be expired, purge it. We do a reverse
         * search since most active entries are first, and most
         * searches are done on most active entries.
         */
        TAILQ_FOREACH_REVERSE_SAFE(fle, &hsh->head, fhead, fle_hash, fle1) {
                if (fle->f.version != IP6VERSION)
                        continue;
                fle6 = (struct flow6_entry *)fle;
                if (bcmp(&r, &fle6->f.r, sizeof(struct flow6_rec)) == 0)
                        break;
                if ((INACTIVE(fle6) && SMALL(fle6)) || AGED(fle6)) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        expire_flow(priv, priv_to_fib(priv, fle->f.r.fib), fle,
                            NG_QUEUE);
                        counter_u64_add(priv->nfinfo_act_exp, 1);
                }
        }

        if (fle != NULL) {                      /* An existent entry. */
                fle6 = (struct flow6_entry *)fle;

                fle6->f.bytes += plen;
                fle6->f.packets ++;
                fle6->f.tcp_flags |= tcp_flags;
                fle6->f.last = time_uptime;

                /*
                 * We have the following reasons to expire flow in active way:
                 * - it hit active timeout
                 * - a TCP connection closed
                 * - it is going to overflow counter
                 */
                if (tcp_flags & TH_FIN || tcp_flags & TH_RST || AGED(fle6) ||
                    (fle6->f.bytes >= (CNTR_MAX - IF_MAXMTU)) ) {
                        TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                        expire_flow(priv, priv_to_fib(priv, fle->f.r.fib), fle,
                            NG_QUEUE);
                        counter_u64_add(priv->nfinfo_act_exp, 1);
                } else {
                        /*
                         * It is the newest, move it to the tail,
                         * if it isn't there already. Next search will
                         * locate it quicker.
                         */
                        if (fle != TAILQ_LAST(&hsh->head, fhead)) {
                                TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                                TAILQ_INSERT_TAIL(&hsh->head, fle, fle_hash);
                        }
                }
        } else                          /* A new flow entry. */
                error = hash6_insert(priv, hsh, &r, plen, flags, tcp_flags);

        mtx_unlock(&hsh->mtx);

        return (error);
}
#endif

/*
 * Return records from cache to userland.
 *
 * TODO: matching particular IP should be done in kernel, here.
 */
int
ng_netflow_flow_show(priv_p priv, struct ngnf_show_header *req,
struct ngnf_show_header *resp)
{
        struct flow_hash_entry  *hsh;
        struct flow_entry       *fle;
        struct flow_entry_data  *data = (struct flow_entry_data *)(resp + 1);
#ifdef INET6
        struct flow6_entry_data *data6 = (struct flow6_entry_data *)(resp + 1);
#endif
        int     i, max;

        i = req->hash_id;
        if (i > NBUCKETS-1)
                return (EINVAL);

#ifdef INET6
        if (req->version == 6) {
                resp->version = 6;
                hsh = priv->hash6 + i;
                max = NREC6_AT_ONCE;
        } else
#endif
        if (req->version == 4) {
                resp->version = 4;
                hsh = priv->hash + i;
                max = NREC_AT_ONCE;
        } else
                return (EINVAL);

        /*
         * We will transfer not more than NREC_AT_ONCE. More data
         * will come in next message.
         * We send current hash index and current record number in list 
         * to userland, and userland should return it back to us. 
         * Then, we will restart with new entry.
         *
         * The resulting cache snapshot can be inaccurate if flow expiration
         * is taking place on hash item between userland data requests for 
         * this hash item id.
         */
        resp->nentries = 0;
        for (; i < NBUCKETS; hsh++, i++) {
                int list_id;

                if (mtx_trylock(&hsh->mtx) == 0) {
                        /* 
                         * Requested hash index is not available,
                         * relay decision to skip or re-request data
                         * to userland.
                         */
                        resp->hash_id = i;
                        resp->list_id = 0;
                        return (0);
                }

                list_id = 0;
                TAILQ_FOREACH(fle, &hsh->head, fle_hash) {
                        if (hsh->mtx.mtx_lock & MTX_WAITERS) {
                                resp->hash_id = i;
                                resp->list_id = list_id;
                                mtx_unlock(&hsh->mtx);
                                return (0);
                        }

                        list_id++;
                        /* Search for particular record in list. */
                        if (req->list_id > 0) {
                                if (list_id < req->list_id)
                                        continue;

                                /* Requested list position found. */
                                req->list_id = 0;
                        }
#ifdef INET6
                        if (req->version == 6) {
                                struct flow6_entry *fle6;

                                fle6 = (struct flow6_entry *)fle;
                                bcopy(&fle6->f, data6 + resp->nentries,
                                    sizeof(fle6->f));
                        } else
#endif
                                bcopy(&fle->f, data + resp->nentries,
                                    sizeof(fle->f));
                        resp->nentries++;
                        if (resp->nentries == max) {
                                resp->hash_id = i;
                                /* 
                                 * If it was the last item in list
                                 * we simply skip to next hash_id.
                                 */
                                resp->list_id = list_id + 1;
                                mtx_unlock(&hsh->mtx);
                                return (0);
                        }
                }
                mtx_unlock(&hsh->mtx);
        }

        resp->hash_id = resp->list_id = 0;

        return (0);
}

/* We have full datagram in privdata. Send it to export hook. */
static int
export_send(priv_p priv, fib_export_p fe, item_p item, int flags)
{
        struct mbuf *m = NGI_M(item);
        struct netflow_v5_export_dgram *dgram = mtod(m,
                                        struct netflow_v5_export_dgram *);
        struct netflow_v5_header *header = &dgram->header;
        struct timespec ts;
        int error = 0;

        /* Fill mbuf header. */
        m->m_len = m->m_pkthdr.len = sizeof(struct netflow_v5_record) *
           header->count + sizeof(struct netflow_v5_header);

        /* Fill export header. */
        header->sys_uptime = htonl(MILLIUPTIME(time_uptime));
        getnanotime(&ts);
        header->unix_secs  = htonl(ts.tv_sec);
        header->unix_nsecs = htonl(ts.tv_nsec);
        header->engine_type = 0;
        header->engine_id = fe->domain_id;
        header->pad = 0;
        header->flow_seq = htonl(atomic_fetchadd_32(&fe->flow_seq,
            header->count));
        header->count = htons(header->count);

        if (priv->export != NULL)
                NG_FWD_ITEM_HOOK_FLAGS(error, item, priv->export, flags);
        else
                NG_FREE_ITEM(item);

        return (error);
}

/* Add export record to dgram. */
static int
export_add(item_p item, struct flow_entry *fle)
{
        struct netflow_v5_export_dgram *dgram = mtod(NGI_M(item),
                                        struct netflow_v5_export_dgram *);
        struct netflow_v5_header *header = &dgram->header;
        struct netflow_v5_record *rec;

        rec = &dgram->r[header->count];
        header->count ++;

        KASSERT(header->count <= NETFLOW_V5_MAX_RECORDS,
            ("ng_netflow: export too big"));

        /* Fill in export record. */
        rec->src_addr = fle->f.r.r_src.s_addr;
        rec->dst_addr = fle->f.r.r_dst.s_addr;
        rec->next_hop = fle->f.next_hop.s_addr;
        rec->i_ifx    = htons(fle->f.fle_i_ifx);
        rec->o_ifx    = htons(fle->f.fle_o_ifx);
        rec->packets  = htonl(fle->f.packets);
        rec->octets   = htonl(fle->f.bytes);
        rec->first    = htonl(MILLIUPTIME(fle->f.first));
        rec->last     = htonl(MILLIUPTIME(fle->f.last));
        rec->s_port   = fle->f.r.r_sport;
        rec->d_port   = fle->f.r.r_dport;
        rec->flags    = fle->f.tcp_flags;
        rec->prot     = fle->f.r.r_ip_p;
        rec->tos      = fle->f.r.r_tos;
        rec->dst_mask = fle->f.dst_mask;
        rec->src_mask = fle->f.src_mask;
        rec->pad1     = 0;
        rec->pad2     = 0;

        /* Not supported fields. */
        rec->src_as = rec->dst_as = 0;

        if (header->count == NETFLOW_V5_MAX_RECORDS)
                return (1); /* end of datagram */
        else
                return (0);     
}

/* Periodic flow expiry run. */
void
ng_netflow_expire(void *arg)
{
        struct flow_entry       *fle, *fle1;
        struct flow_hash_entry  *hsh;
        priv_p                  priv = (priv_p )arg;
        int                     used, i;

        /*
         * Going through all the cache.
         */
        used = uma_zone_get_cur(priv->zone);
        for (hsh = priv->hash, i = 0; i < NBUCKETS; hsh++, i++) {
                /*
                 * Skip entries, that are already being worked on.
                 */
                if (mtx_trylock(&hsh->mtx) == 0)
                        continue;

                TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
                        /*
                         * Interrupt thread wants this entry!
                         * Quick! Quick! Bail out!
                         */
                        if (hsh->mtx.mtx_lock & MTX_WAITERS)
                                break;

                        /*
                         * Don't expire aggressively while hash collision
                         * ratio is predicted small.
                         */
                        if (used <= (NBUCKETS*2) && !INACTIVE(fle))
                                break;

                        if ((INACTIVE(fle) && (SMALL(fle) ||
                            (used > (NBUCKETS*2)))) || AGED(fle)) {
                                TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                                expire_flow(priv, priv_to_fib(priv,
                                    fle->f.r.fib), fle, NG_NOFLAGS);
                                used--;
                                counter_u64_add(priv->nfinfo_inact_exp, 1);
                        }
                }
                mtx_unlock(&hsh->mtx);
        }

#ifdef INET6
        used = uma_zone_get_cur(priv->zone6);
        for (hsh = priv->hash6, i = 0; i < NBUCKETS; hsh++, i++) {
                struct flow6_entry      *fle6;

                /*
                 * Skip entries, that are already being worked on.
                 */
                if (mtx_trylock(&hsh->mtx) == 0)
                        continue;

                TAILQ_FOREACH_SAFE(fle, &hsh->head, fle_hash, fle1) {
                        fle6 = (struct flow6_entry *)fle;
                        /*
                         * Interrupt thread wants this entry!
                         * Quick! Quick! Bail out!
                         */
                        if (hsh->mtx.mtx_lock & MTX_WAITERS)
                                break;

                        /*
                         * Don't expire aggressively while hash collision
                         * ratio is predicted small.
                         */
                        if (used <= (NBUCKETS*2) && !INACTIVE(fle6))
                                break;

                        if ((INACTIVE(fle6) && (SMALL(fle6) ||
                            (used > (NBUCKETS*2)))) || AGED(fle6)) {
                                TAILQ_REMOVE(&hsh->head, fle, fle_hash);
                                expire_flow(priv, priv_to_fib(priv,
                                    fle->f.r.fib), fle, NG_NOFLAGS);
                                used--;
                                counter_u64_add(priv->nfinfo_inact_exp, 1);
                        }
                }
                mtx_unlock(&hsh->mtx);
        }
#endif

        /* Schedule next expire. */
        callout_reset(&priv->exp_callout, (1*hz), &ng_netflow_expire,
            (void *)priv);
}