/*      $NetBSD: ieee8023ad_lacp.c,v 1.13 2021/11/30 01:17:02 yamaguchi Exp $   */

/*-
 * Copyright (c)2005 YAMAMOTO Takashi,
 * 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.
 */

#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: ieee8023ad_lacp.c,v 1.13 2021/11/30 01:17:02 yamaguchi Exp $");

#include <sys/param.h>
#include <sys/callout.h>
#include <sys/mbuf.h>
#include <sys/systm.h>
#include <sys/malloc.h>
#include <sys/kernel.h> /* hz */

#include <net/if.h>
#include <net/if_dl.h>
#include <net/if_ether.h>
#include <net/if_media.h>
#include <net/ether_slowprotocols.h>

#include <net/agr/if_agrvar_impl.h>
#include <net/agr/if_agrsubr.h>
#include <net/agr/ieee8023_tlv.h>
#include <net/agr/ieee8023ad.h>
#include <net/agr/ieee8023ad_lacp.h>
#include <net/agr/ieee8023ad_lacp_impl.h>
#include <net/agr/ieee8023ad_impl.h>
#include <net/agr/ieee8023ad_lacp_sm.h>
#include <net/agr/ieee8023ad_lacp_debug.h>

static void lacp_fill_actorinfo(struct agr_port *, struct lacp_peerinfo *);

static uint64_t lacp_aggregator_bandwidth(struct lacp_aggregator *);
static void lacp_suppress_distributing(struct lacp_softc *,
    struct lacp_aggregator *);
static void lacp_transit_expire(void *);
static void lacp_select_active_aggregator(struct lacp_softc *);
static uint16_t lacp_compose_key(struct lacp_port *);

/*
 * actor system priority and port priority.
 * XXX should be configurable.
 */

#define LACP_SYSTEM_PRIO        0x8000
#define LACP_PORT_PRIO          0x8000

static const struct tlv_template lacp_info_tlv_template[] = {
        { LACP_TYPE_ACTORINFO,
            sizeof(struct tlvhdr) + sizeof(struct lacp_peerinfo) },
        { LACP_TYPE_PARTNERINFO,
            sizeof(struct tlvhdr) + sizeof(struct lacp_peerinfo) },
        { LACP_TYPE_COLLECTORINFO,
            sizeof(struct tlvhdr) + sizeof(struct lacp_collectorinfo) },
        { 0, 0 },
};

/*
 * ieee8023ad_lacp_input: process lacpdu
 *
 * => called from ether_input.  (ie. at IPL_NET)
 *
 * XXX is it better to defer processing to lower IPL?
 * XXX anyway input rate should be very low...
 */

int
ieee8023ad_lacp_input(struct ifnet *ifp, struct mbuf *m)
{
        struct lacpdu *du;
        struct agr_softc *sc;
        struct agr_port *port;
        struct lacp_port *lp;
        int error = 0;

        port = ifp->if_lagg; /* XXX race with agr_remport. */
        if (__predict_false(port->port_flags & AGRPORT_DETACHING)) {
                goto bad;
        }

        sc = AGR_SC_FROM_PORT(port);
        KASSERT(port);

        /* running static config? */
        if (AGR_STATIC(sc)) {
                /* static config, no lacp */
                goto bad;
        }


        if (m->m_pkthdr.len != sizeof(*du)) {
                goto bad;
        }

        if ((m->m_flags & M_MCAST) == 0) {
                goto bad;
        }

        if (m->m_len < sizeof(*du)) {
                m = m_pullup(m, sizeof(*du));
                if (m == NULL) {
                        return ENOMEM;
                }
        }

        du = mtod(m, struct lacpdu *);

        if (memcmp(&du->ldu_eh.ether_dhost,
            &ethermulticastaddr_slowprotocols, ETHER_ADDR_LEN)) {
                goto bad;
        }

        KASSERT(du->ldu_sph.sph_subtype == SLOWPROTOCOLS_SUBTYPE_LACP);

        /*
         * ignore the version for compatibility with
         * the future protocol revisions.
         */

#if 0
        if (du->ldu_sph.sph_version != 1) {
                goto bad;
        }
#endif

        /*
         * ignore tlv types for compatibility with
         * the future protocol revisions.
         */

        if (tlv_check(du, sizeof(*du), &du->ldu_tlv_actor,
            lacp_info_tlv_template, false)) {
                goto bad;
        }

        AGR_LOCK(sc);
        lp = LACP_PORT(port);

#if defined(LACP_DEBUG)
        if (lacpdebug) {
                LACP_DPRINTF((lp, "lacpdu receive\n"));
                lacp_dump_lacpdu(du);
        }
#endif /* defined(LACP_DEBUG) */
        lacp_sm_rx(lp, du);

        AGR_UNLOCK(sc);

        m_freem(m);

        return error;

bad:
        m_freem(m);
        return EINVAL;
}

static void
lacp_fill_actorinfo(struct agr_port *port, struct lacp_peerinfo *info)
{
        struct lacp_port *lp = LACP_PORT(port);

        info->lip_systemid.lsi_prio = htobe16(LACP_SYSTEM_PRIO);
        memcpy(&info->lip_systemid.lsi_mac,
            CLLADDR(port->port_ifp->if_sadl), ETHER_ADDR_LEN);
        info->lip_portid.lpi_prio = htobe16(LACP_PORT_PRIO);
        info->lip_portid.lpi_portno = htobe16(port->port_ifp->if_index);
        info->lip_state = lp->lp_state;
}

int
lacp_xmit_lacpdu(struct lacp_port *lp)
{
        struct agr_port *port = lp->lp_agrport;
        struct mbuf *m;
        struct lacpdu *du;
        int error;

        /* running static config? */
        if (AGR_STATIC(AGR_SC_FROM_PORT(port))) {
                /* static config, no lacp transmit */
                return 0;
        }

        KDASSERT(MHLEN >= sizeof(*du));

        m = m_gethdr(M_DONTWAIT, MT_DATA);
        if (m == NULL) {
                return ENOMEM;
        }
        m->m_len = m->m_pkthdr.len = sizeof(*du);

        du = mtod(m, struct lacpdu *);
        memset(du, 0, sizeof(*du));

        memcpy(&du->ldu_eh.ether_dhost, ethermulticastaddr_slowprotocols,
            ETHER_ADDR_LEN);
        memcpy(&du->ldu_eh.ether_shost, &port->port_origlladdr, ETHER_ADDR_LEN);
        du->ldu_eh.ether_type = htobe16(ETHERTYPE_SLOWPROTOCOLS);

        du->ldu_sph.sph_subtype = SLOWPROTOCOLS_SUBTYPE_LACP;
        du->ldu_sph.sph_version = 1;

        TLV_SET(&du->ldu_tlv_actor, LACP_TYPE_ACTORINFO, sizeof(du->ldu_actor));
        du->ldu_actor = lp->lp_actor;

        TLV_SET(&du->ldu_tlv_partner, LACP_TYPE_PARTNERINFO,
            sizeof(du->ldu_partner));
        du->ldu_partner = lp->lp_partner;

        TLV_SET(&du->ldu_tlv_collector, LACP_TYPE_COLLECTORINFO,
            sizeof(du->ldu_collector));
        du->ldu_collector.lci_maxdelay = 0;

#if defined(LACP_DEBUG)
        if (lacpdebug) {
                LACP_DPRINTF((lp, "lacpdu transmit\n"));
                lacp_dump_lacpdu(du);
        }
#endif /* defined(LACP_DEBUG) */

        m->m_flags |= M_MCAST;

        /*
         * XXX should use higher priority queue.
         * otherwise network congestion can break aggregation.
         */

        error = agr_xmit_frame(port->port_ifp, m);
        return error;
}

void
ieee8023ad_lacp_portstate(struct agr_port *port)
{
        struct lacp_port *lp = LACP_PORT(port);
        u_int media = port->port_media;
        uint8_t old_state;
        uint16_t old_key;

        AGR_ASSERT_LOCKED(AGR_SC_FROM_PORT(port));

        LACP_DPRINTF((lp, "media changed 0x%x -> 0x%x\n", lp->lp_media, media));

        old_state = lp->lp_state;
        old_key = lp->lp_key;

        lp->lp_media = media;
        if ((media & IFM_HDX) != 0) {
                lp->lp_state &= ~LACP_STATE_AGGREGATION;
        } else {
                lp->lp_state |= LACP_STATE_AGGREGATION;
        }
        lp->lp_key = lacp_compose_key(lp);

        if (old_state != lp->lp_state || old_key != lp->lp_key) {
                LACP_DPRINTF((lp, "-> UNSELECTED\n"));
                lp->lp_selected = LACP_UNSELECTED;
        }
}

void
ieee8023ad_lacp_porttick(struct agr_softc *sc, struct agr_port *port)
{
        struct lacp_port *lp = LACP_PORT(port);

        AGR_ASSERT_LOCKED(sc);

        lacp_run_timers(lp);

        lacp_select(lp);
        lacp_sm_mux(lp);
        lacp_sm_tx(lp);
        lacp_sm_ptx_tx_schedule(lp);
}

void
lacp_portinit(struct agr_port *port)
{
        struct lacp_port *lp = LACP_PORT(port);
        bool active = true; /* XXX should be configurable */
        bool fast = false; /* XXX should be configurable */

        lp->lp_agrport = port;
        lacp_fill_actorinfo(port, &lp->lp_actor);
        lp->lp_state =
            (active ? LACP_STATE_ACTIVITY : 0) |
            (fast ? LACP_STATE_TIMEOUT : 0);
        lp->lp_aggregator = NULL;
        lp->lp_media = port->port_media; /* XXX */
        lp->lp_key = lacp_compose_key(lp);
        lacp_sm_rx_set_expired(lp);
}

void
lacp_portfini(struct agr_port *port)
{
        struct lacp_port *lp = LACP_PORT(port);
        struct lacp_aggregator *la = lp->lp_aggregator;
        int i;

        LACP_DPRINTF((lp, "portfini\n"));

        for (i = 0; i < LACP_NTIMER; i++) {
                LACP_TIMER_DISARM(lp, i);
        }

        if (la == NULL) {
                return;
        }

        lacp_disable_distributing(lp);
        lacp_unselect(lp);
}

/* -------------------- */
void
lacp_disable_collecting(struct lacp_port *lp)
{
        struct agr_port *port = lp->lp_agrport;

        lp->lp_state &= ~LACP_STATE_COLLECTING;
        port->port_flags &= ~AGRPORT_COLLECTING;
}

void
lacp_enable_collecting(struct lacp_port *lp)
{
        struct agr_port *port = lp->lp_agrport;

        lp->lp_state |= LACP_STATE_COLLECTING;
        port->port_flags |= AGRPORT_COLLECTING;
}

void
lacp_disable_distributing(struct lacp_port *lp)
{
        struct agr_port *port = lp->lp_agrport;
        struct lacp_aggregator *la = lp->lp_aggregator;
        struct lacp_softc *lsc = LACP_SOFTC(AGR_SC_FROM_PORT(port));
#if defined(LACP_DEBUG)
        char buf[LACP_LAGIDSTR_MAX+1];
#endif /* defined(LACP_DEBUG) */

        if ((lp->lp_state & LACP_STATE_DISTRIBUTING) == 0) {
                return;
        }

        KASSERT(la);
        KASSERT(!TAILQ_EMPTY(&la->la_ports));
        KASSERT(la->la_nports > 0);
        KASSERT(la->la_refcnt >= la->la_nports);

        LACP_DPRINTF((lp, "disable distributing on aggregator %s, "
            "nports %d -> %d\n",
            lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
            la->la_nports, la->la_nports - 1));

        TAILQ_REMOVE(&la->la_ports, lp, lp_dist_q);
        la->la_nports--;

        lacp_suppress_distributing(lsc, la);

        lp->lp_state &= ~LACP_STATE_DISTRIBUTING;
        port->port_flags &= ~AGRPORT_DISTRIBUTING;

        if (lsc->lsc_active_aggregator == la) {
                lacp_select_active_aggregator(lsc);
        }
}

void
lacp_enable_distributing(struct lacp_port *lp)
{
        struct agr_port *port = lp->lp_agrport;
        struct lacp_aggregator *la = lp->lp_aggregator;
        struct lacp_softc *lsc = LACP_SOFTC(AGR_SC_FROM_PORT(port));
#if defined(LACP_DEBUG)
        char buf[LACP_LAGIDSTR_MAX+1];
#endif /* defined(LACP_DEBUG) */

        if ((lp->lp_state & LACP_STATE_DISTRIBUTING) != 0) {
                return;
        }

        KASSERT(la);

        LACP_DPRINTF((lp, "enable distributing on aggregator %s, "
            "nports %d -> %d\n",
            lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
            la->la_nports, la->la_nports + 1));

        KASSERT(la->la_refcnt > la->la_nports);
        TAILQ_INSERT_HEAD(&la->la_ports, lp, lp_dist_q);
        la->la_nports++;

        lacp_suppress_distributing(lsc, la);

        lp->lp_state |= LACP_STATE_DISTRIBUTING;
        port->port_flags |= AGRPORT_DISTRIBUTING;

        if (lsc->lsc_active_aggregator != la) {
                lacp_select_active_aggregator(lsc);
        }
}

static void
lacp_transit_expire(void *vp)
{
        struct agr_softc *sc = vp;
        struct lacp_softc *lsc = LACP_SOFTC(sc);

        AGR_LOCK(sc);
        LACP_DPRINTF((NULL, "%s\n", __func__));
        lsc->lsc_suppress_distributing = false;
        AGR_UNLOCK(sc);
}

/* -------------------- */
/* XXX */
void
ieee8023ad_portinit(struct agr_port *port)
{
        struct ieee8023ad_port *iport = IEEE8023AD_PORT(port);

        memset(iport, 0, sizeof(*iport));

        lacp_portinit(port);
}

void
ieee8023ad_portfini(struct agr_port *port)
{
        struct agr_softc *sc = AGR_SC_FROM_PORT(port);

        AGR_LOCK(sc);

        lacp_portfini(port);

        AGR_UNLOCK(sc);
}

void
ieee8023ad_ctor(struct agr_softc *sc)
{
        struct ieee8023ad_softc *isc = IEEE8023AD_SOFTC(sc);
        struct lacp_softc *lsc = &isc->isc_lacpsc;

        lsc->lsc_active_aggregator = NULL;
        TAILQ_INIT(&lsc->lsc_aggregators);
        callout_init(&lsc->lsc_transit_callout, 0);
        callout_setfunc(&lsc->lsc_transit_callout, lacp_transit_expire, sc);
}

void
ieee8023ad_dtor(struct agr_softc *sc)
{
        struct ieee8023ad_softc *isc = IEEE8023AD_SOFTC(sc);
        struct lacp_softc *lsc = &isc->isc_lacpsc;

        LACP_DPRINTF((NULL, "%s\n", __func__));

        callout_stop(&lsc->lsc_transit_callout);
        KASSERT(TAILQ_EMPTY(&lsc->lsc_aggregators));
        KASSERT(lsc->lsc_active_aggregator == NULL);
}

/* -------------------- */

struct agr_port *
ieee8023ad_select_tx_port(struct agr_softc *sc, struct mbuf *m)
{
        const struct lacp_softc *lsc = LACP_SOFTC(sc);
        const struct lacp_aggregator *la;
        const struct lacp_port *lp;
        uint32_t hash;
        int nports;

        if (__predict_false(lsc->lsc_suppress_distributing &&
            !AGR_ROUNDROBIN(sc))) {
                LACP_DPRINTF((NULL, "%s: waiting transit\n", __func__));
                if_statinc(&sc->sc_if, if_collisions);  /* XXX abuse */
                return NULL;
        }

        la = lsc->lsc_active_aggregator;
        if (__predict_false(la == NULL)) {
                LACP_DPRINTF((NULL, "%s: no active aggregator\n", __func__));
                return NULL;
        }

        nports = la->la_nports;
        KASSERT(nports > 0);

        if (AGR_ROUNDROBIN(sc)) {
                /* packet ordering rule violation */
                hash = sc->sc_rr_counter++;
        } else {
                hash = (*sc->sc_iftop->iftop_hashmbuf)(sc, m);
        }
        hash %= nports;
        lp = TAILQ_FIRST(&la->la_ports);
        KASSERT(lp != NULL);
        while (hash--) {
                lp = TAILQ_NEXT(lp, lp_dist_q);
                KASSERT(lp != NULL);
        }

        KASSERT((lp->lp_state & LACP_STATE_DISTRIBUTING) != 0);

        return lp->lp_agrport;
}

/*
 * lacp_suppress_distributing: drop transmit packets for a while
 * to preserve packet ordering.
 */

static void
lacp_suppress_distributing(struct lacp_softc *lsc, struct lacp_aggregator *la)
{

        if (lsc->lsc_active_aggregator != la) {
                return;
        }

        LACP_DPRINTF((NULL, "%s\n", __func__));
        lsc->lsc_suppress_distributing = true;
        /* XXX should consider collector max delay */
        callout_schedule(&lsc->lsc_transit_callout,
            LACP_TRANSIT_DELAY * hz / 1000);
}

/* -------------------- */

int
lacp_compare_peerinfo(const struct lacp_peerinfo *a,
    const struct lacp_peerinfo *b)
{

        return memcmp(a, b, offsetof(struct lacp_peerinfo, lip_state));
}

int
lacp_compare_systemid(const struct lacp_systemid *a,
    const struct lacp_systemid *b)
{

        return memcmp(a, b, sizeof(*a));
}

int
lacp_compare_portid(const struct lacp_portid *a,
    const struct lacp_portid *b)
{

        return memcmp(a, b, sizeof(*a));
}

/* -------------------- */

static uint64_t
lacp_aggregator_bandwidth(struct lacp_aggregator *la)
{
        struct lacp_port *lp;
        uint64_t speed;

        lp = TAILQ_FIRST(&la->la_ports);
        if (lp == NULL) {
                return 0;
        }

        speed = ifmedia_baudrate(lp->lp_media);
        speed *= la->la_nports;
        if (speed == 0) {
                LACP_DPRINTF((lp, "speed 0? media=0x%x nports=%d\n",
                    lp->lp_media, la->la_nports));
        }

        return speed;
}

/*
 * lacp_select_active_aggregator: select an aggregator to be used to transmit
 * packets from agr(4) interface.
 */

static void
lacp_select_active_aggregator(struct lacp_softc *lsc)
{
        struct lacp_aggregator *la;
        struct lacp_aggregator *best_la = NULL;
        uint64_t best_speed = 0;
#if defined(LACP_DEBUG)
        char buf[LACP_LAGIDSTR_MAX+1];
#endif /* defined(LACP_DEBUG) */

        LACP_DPRINTF((NULL, "%s:\n", __func__));

        TAILQ_FOREACH(la, &lsc->lsc_aggregators, la_q) {
                uint64_t speed;

                if (la->la_nports == 0) {
                        continue;
                }

                speed = lacp_aggregator_bandwidth(la);
                LACP_DPRINTF((NULL, "%s, speed=%" PRIu64 ", nports=%d\n",
                    lacp_format_lagid_aggregator(la, buf, sizeof(buf)),
                    speed, la->la_nports));
                if (speed > best_speed ||
                    (speed == best_speed &&
                    la == lsc->lsc_active_aggregator)) {
                        best_la = la;
                        best_speed = speed;
                }
        }

        KASSERT(best_la == NULL || best_la->la_nports > 0);
        KASSERT(best_la == NULL || !TAILQ_EMPTY(&best_la->la_ports));

#if defined(LACP_DEBUG)
        if (lsc->lsc_active_aggregator != best_la) {
                LACP_DPRINTF((NULL, "active aggregator changed\n"));
                LACP_DPRINTF((NULL, "old %s\n",
                    lacp_format_lagid_aggregator(lsc->lsc_active_aggregator,
                    buf, sizeof(buf))));
        } else {
                LACP_DPRINTF((NULL, "active aggregator not changed\n"));
        }
        LACP_DPRINTF((NULL, "new %s\n",
            lacp_format_lagid_aggregator(best_la, buf, sizeof(buf))));
#endif /* defined(LACP_DEBUG) */

        if (lsc->lsc_active_aggregator != best_la) {
                lsc->lsc_active_aggregator = best_la;
                if (best_la) {
                        lacp_suppress_distributing(lsc, best_la);
                }
        }
}

uint16_t
lacp_compose_key(struct lacp_port *lp)
{
        u_int media = lp->lp_media;
        uint16_t key;

        KASSERT(IFM_TYPE(media) == IFM_ETHER);

        if (!(lp->lp_state & LACP_STATE_AGGREGATION)) {

                /*
                 * non-aggregatable links should have unique keys.
                 *
                 * XXX this isn't really unique as if_index is 16 bit.
                 */

                /* bit 0..14:   (some bits of) if_index of this port */
                key = lp->lp_agrport->port_ifp->if_index;
                /* bit 15:      1 */
                key |= 0x8000;
        } else {
                u_int subtype = IFM_SUBTYPE(media);

                KASSERT((media & IFM_HDX) == 0); /* should be handled above */
                KASSERT((subtype & 0x1f) == subtype);

                /* bit 0..4:    IFM_SUBTYPE */
                key = subtype;
                /* bit 5..14:   (some bits of) if_index of agr device */
                key |= 0x7fe0 & ((lp->lp_agrport->port_agrifp->if_index) << 5);
                /* bit 15:      0 */
        }

        return htobe16(key);
}