/*      $NetBSD: athrate-amrr.c,v 1.13 2019/11/10 21:16:35 chs Exp $ */

/*-
 * Copyright (c) 2004 INRIA
 * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
 * 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,
 *    without modification.
 * 2. Redistributions in binary form must reproduce at minimum a disclaimer
 *    similar to the "NO WARRANTY" disclaimer below ("Disclaimer") and any
 *    redistribution must be conditioned upon including a substantially
 *    similar Disclaimer requirement for further binary redistribution.
 * 3. Neither the names of the above-listed copyright holders nor the names
 *    of any contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * Alternatively, this software may be distributed under the terms of the
 * GNU General Public License ("GPL") version 2 as published by the Free
 * Software Foundation.
 *
 * NO WARRANTY
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF NONINFRINGEMENT, MERCHANTIBILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
 * THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR 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 DAMAGES.
 *
 */

#include <sys/cdefs.h>
#ifdef __FreeBSD__
__FBSDID("$FreeBSD: src/sys/dev/ath/ath_rate/amrr/amrr.c,v 1.10 2005/08/09 10:19:43 rwatson Exp $");
#endif
#ifdef __NetBSD__
__KERNEL_RCSID(0, "$NetBSD: athrate-amrr.c,v 1.13 2019/11/10 21:16:35 chs Exp $");
#endif

/*
 * AMRR rate control. See:
 * http://www-sop.inria.fr/rapports/sophia/RR-5208.html
 * "IEEE 802.11 Rate Adaptation: A Practical Approach" by
 *    Mathieu Lacage, Hossein Manshaei, Thierry Turletti
 */
#include "opt_inet.h"

#include <sys/param.h>
#include <sys/systm.h> 
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/errno.h>
#include <sys/bus.h>
#include <sys/socket.h>
 
#include <net/if.h>
#include <net/if_media.h>
#include <net/if_arp.h>
#include <net/if_ether.h>               /* XXX for ether_sprintf */

#include <net80211/ieee80211_var.h>

#include <net/bpf.h>

#ifdef INET
#include <netinet/in.h> 
#endif

#include <dev/ic/athvar.h>
#include <dev/ic/athrate-amrr.h>

#include <external/isc/atheros_hal/dist/ah.h>

#define AMRR_DEBUG
#ifdef AMRR_DEBUG
#define DPRINTF(sc, _fmt, ...) do {                                     \
        if (sc->sc_debug & 0x10)                                        \
                printf(_fmt, __VA_ARGS__);                              \
} while (0)
#else
#define DPRINTF(sc, _fmt, ...)
#endif

static  int ath_rateinterval = 1000;            /* rate ctl interval (ms)  */
static  int ath_rate_max_success_threshold = 10;
static  int ath_rate_min_success_threshold = 1;

static void     ath_ratectl(void *);
static void     ath_rate_update(struct ath_softc *, struct ieee80211_node *,
                        int rate);
static void     ath_rate_ctl_start(struct ath_softc *, struct ieee80211_node *);
static void     ath_rate_ctl(void *, struct ieee80211_node *);

void
ath_rate_node_init(struct ath_softc *sc, struct ath_node *an)
{
        /* NB: assumed to be zero'd by caller */
        ath_rate_update(sc, &an->an_node, 0);
}

void
ath_rate_node_cleanup(struct ath_softc *sc, struct ath_node *an)
{
}

void
ath_rate_findrate(struct ath_softc *sc, struct ath_node *an,
        int shortPreamble, size_t frameLen,
        u_int8_t *rix, int *try0, u_int8_t *txrate)
{
        struct amrr_node *amn = ATH_NODE_AMRR(an);

        *rix = amn->amn_tx_rix0;
        *try0 = amn->amn_tx_try0;
        if (shortPreamble)
                *txrate = amn->amn_tx_rate0sp;
        else
                *txrate = amn->amn_tx_rate0;
}

void
ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
        struct ath_desc *ds, int shortPreamble, u_int8_t rix)
{
        struct amrr_node *amn = ATH_NODE_AMRR(an);

        ath_hal_setupxtxdesc(sc->sc_ah, ds
                , amn->amn_tx_rate1sp, amn->amn_tx_try1 /* series 1 */
                , amn->amn_tx_rate2sp, amn->amn_tx_try2 /* series 2 */
                , amn->amn_tx_rate3sp, amn->amn_tx_try3 /* series 3 */
        );
}

void
ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
        const struct ath_desc *ds, const struct ath_desc *ds0)
{
        struct amrr_node *amn = ATH_NODE_AMRR(an);
        int sr = ds->ds_txstat.ts_shortretry;
        int lr = ds->ds_txstat.ts_longretry;
        int retry_count = sr + lr;

        amn->amn_tx_try0_cnt++;
        if (retry_count == 1) {
                amn->amn_tx_try1_cnt++;
        } else if (retry_count == 2) {
                amn->amn_tx_try1_cnt++;
                amn->amn_tx_try2_cnt++;
        } else if (retry_count == 3) {
                amn->amn_tx_try1_cnt++;
                amn->amn_tx_try2_cnt++;
                amn->amn_tx_try3_cnt++;
        } else if (retry_count > 3) {
                amn->amn_tx_try1_cnt++;
                amn->amn_tx_try2_cnt++;
                amn->amn_tx_try3_cnt++;
                amn->amn_tx_failure_cnt++;
        }
}

void
ath_rate_newassoc(struct ath_softc *sc, struct ath_node *an, int isnew)
{
        if (isnew)
                ath_rate_ctl_start(sc, &an->an_node);
}

static void 
node_reset (struct amrr_node *amn)
{
        amn->amn_tx_try0_cnt = 0;
        amn->amn_tx_try1_cnt = 0;
        amn->amn_tx_try2_cnt = 0;
        amn->amn_tx_try3_cnt = 0;
        amn->amn_tx_failure_cnt = 0;
        amn->amn_success = 0;
        amn->amn_recovery = 0;
        amn->amn_success_threshold = ath_rate_min_success_threshold;
}


/**
 * The code below assumes that we are dealing with hardware multi rate retry
 * I have no idea what will happen if you try to use this module with another
 * type of hardware. Your machine might catch fire or it might work with
 * horrible performance...
 */
static void
ath_rate_update(struct ath_softc *sc, struct ieee80211_node *ni, int rate)
{
        struct ath_node *an = ATH_NODE(ni);
        struct amrr_node *amn = ATH_NODE_AMRR(an);
        const HAL_RATE_TABLE *rt = sc->sc_currates;
        u_int8_t rix;

        KASSERTMSG(rt != NULL, "no rate table, mode %u", sc->sc_curmode);

        DPRINTF(sc, "%s: set xmit rate for %s to %dM\n",
            __func__, ether_sprintf(ni->ni_macaddr),
            ni->ni_rates.rs_nrates > 0 ?
                (ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL) / 2 : 0);

        ni->ni_txrate = rate;
        /*
         * Before associating a node has no rate set setup
         * so we can't calculate any transmit codes to use.
         * This is ok since we should never be sending anything
         * but management frames and those always go at the
         * lowest hardware rate.
         */
        if (ni->ni_rates.rs_nrates > 0) {
                amn->amn_tx_rix0 = sc->sc_rixmap[
                                               ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL];
                amn->amn_tx_rate0 = rt->info[amn->amn_tx_rix0].rateCode;
                amn->amn_tx_rate0sp = amn->amn_tx_rate0 |
                        rt->info[amn->amn_tx_rix0].shortPreamble;
                if (sc->sc_mrretry) {
                        amn->amn_tx_try0 = 1;
                        amn->amn_tx_try1 = 1;
                        amn->amn_tx_try2 = 1;
                        amn->amn_tx_try3 = 1;
                        if (--rate >= 0) {
                                rix = sc->sc_rixmap[
                                                    ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
                                amn->amn_tx_rate1 = rt->info[rix].rateCode;
                                amn->amn_tx_rate1sp = amn->amn_tx_rate1 |
                                        rt->info[rix].shortPreamble;
                        } else {
                                amn->amn_tx_rate1 = amn->amn_tx_rate1sp = 0;
                        }
                        if (--rate >= 0) {
                                rix = sc->sc_rixmap[
                                                    ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
                                amn->amn_tx_rate2 = rt->info[rix].rateCode;
                                amn->amn_tx_rate2sp = amn->amn_tx_rate2 |
                                        rt->info[rix].shortPreamble;
                        } else {
                                amn->amn_tx_rate2 = amn->amn_tx_rate2sp = 0;
                        }
                        if (rate > 0) {
                                /* NB: only do this if we didn't already do it above */
                                amn->amn_tx_rate3 = rt->info[0].rateCode;
                                amn->amn_tx_rate3sp =
                                        an->an_tx_rate3 | rt->info[0].shortPreamble;
                        } else {
                                amn->amn_tx_rate3 = amn->amn_tx_rate3sp = 0;
                        }
                } else {
                        amn->amn_tx_try0 = ATH_TXMAXTRY;
                        /* theorically, these statements are useless because
                         *  the code which uses them tests for an_tx_try0 == ATH_TXMAXTRY
                         */
                        amn->amn_tx_try1 = 0;
                        amn->amn_tx_try2 = 0;
                        amn->amn_tx_try3 = 0;
                        amn->amn_tx_rate1 = amn->amn_tx_rate1sp = 0;
                        amn->amn_tx_rate2 = amn->amn_tx_rate2sp = 0;
                        amn->amn_tx_rate3 = amn->amn_tx_rate3sp = 0;
                }
        }
        node_reset (amn);
}

/*
 * Set the starting transmit rate for a node.
 */
static void
ath_rate_ctl_start(struct ath_softc *sc, struct ieee80211_node *ni)
{
#define RATE(_ix)       (ni->ni_rates.rs_rates[(_ix)] & IEEE80211_RATE_VAL)
        struct ieee80211com *ic = &sc->sc_ic;
        int srate;

        KASSERTMSG(ni->ni_rates.rs_nrates > 0, "no rates");
        if (ic->ic_fixed_rate == IEEE80211_FIXED_RATE_NONE) {
                /*
                 * No fixed rate is requested. For 11b start with
                 * the highest negotiated rate; otherwise, for 11g
                 * and 11a, we start "in the middle" at 24Mb or 36Mb.
                 */
                srate = ni->ni_rates.rs_nrates - 1;
                if (sc->sc_curmode != IEEE80211_MODE_11B) {
                        /*
                         * Scan the negotiated rate set to find the
                         * closest rate.
                         */
                        /* NB: the rate set is assumed sorted */
                        for (; srate >= 0 && RATE(srate) > 72; srate--)
                                ;
                        KASSERTMSG(srate >= 0, "bogus rate set");
                }
        } else {
                /*
                 * A fixed rate is to be used; ic_fixed_rate is an
                 * index into the supported rate set.  Convert this
                 * to the index into the negotiated rate set for
                 * the node.  We know the rate is there because the
                 * rate set is checked when the station associates.
                 */
                const struct ieee80211_rateset *rs =
                        &ic->ic_sup_rates[ic->ic_curmode];
                int r = rs->rs_rates[ic->ic_fixed_rate] & IEEE80211_RATE_VAL;
                /* NB: the rate set is assumed sorted */
                srate = ni->ni_rates.rs_nrates - 1;
                for (; srate >= 0 && RATE(srate) != r; srate--)
                        ;
                KASSERTMSG(srate >= 0,
                        "fixed rate %d not in rate set", ic->ic_fixed_rate);
        }
        ath_rate_update(sc, ni, srate);
#undef RATE
}

static void
ath_rate_cb(void *arg, struct ieee80211_node *ni)
{
        struct ath_softc *sc = arg;

        ath_rate_update(sc, ni, 0);
}

/*
 * Reset the rate control state for each 802.11 state transition.
 */
void
ath_rate_newstate(struct ath_softc *sc, enum ieee80211_state state)
{
        struct amrr_softc *asc = (struct amrr_softc *) sc->sc_rc;
        struct ieee80211com *ic = &sc->sc_ic;
        struct ieee80211_node *ni;

        if (state == IEEE80211_S_INIT) {
                callout_stop(&asc->timer);
                return;
        }
        if (ic->ic_opmode == IEEE80211_M_STA) {
                /*
                 * Reset local xmit state; this is really only
                 * meaningful when operating in station mode.
                 */
                ni = ic->ic_bss;
                if (state == IEEE80211_S_RUN) {
                        ath_rate_ctl_start(sc, ni);
                } else {
                        ath_rate_update(sc, ni, 0);
                }
        } else {
                /*
                 * When operating as a station the node table holds
                 * the AP's that were discovered during scanning.
                 * For any other operating mode we want to reset the
                 * tx rate state of each node.
                 */
                ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_cb, sc);
                ath_rate_update(sc, ic->ic_bss, 0);
        }
        if (ic->ic_fixed_rate == IEEE80211_FIXED_RATE_NONE &&
            state == IEEE80211_S_RUN) {
                int interval;
                /*
                 * Start the background rate control thread if we
                 * are not configured to use a fixed xmit rate.
                 */
                interval = ath_rateinterval;
                if (ic->ic_opmode == IEEE80211_M_STA)
                        interval /= 2;
                callout_reset(&asc->timer, (interval * hz) / 1000,
                        ath_ratectl, &sc->sc_if);
        }
}

/* 
 * Examine and potentially adjust the transmit rate.
 */
static void
ath_rate_ctl(void *arg, struct ieee80211_node *ni)
{
        struct ath_softc *sc = arg;
        struct amrr_node *amn = ATH_NODE_AMRR(ATH_NODE (ni));
        int old_rate;

#define is_success(amn) \
(amn->amn_tx_try1_cnt  < (amn->amn_tx_try0_cnt/10))
#define is_enough(amn) \
(amn->amn_tx_try0_cnt > 10)
#define is_failure(amn) \
(amn->amn_tx_try1_cnt > (amn->amn_tx_try0_cnt/3))
#define is_max_rate(ni) \
((ni->ni_txrate + 1) >= ni->ni_rates.rs_nrates)
#define is_min_rate(ni) \
(ni->ni_txrate == 0)

        old_rate = ni->ni_txrate;
  
        DPRINTF (sc, "cnt0: %d cnt1: %d cnt2: %d cnt3: %d -- threshold: %d\n",
                 amn->amn_tx_try0_cnt,
                 amn->amn_tx_try1_cnt,
                 amn->amn_tx_try2_cnt,
                 amn->amn_tx_try3_cnt,
                 amn->amn_success_threshold);
        if (is_success (amn) && is_enough (amn)) {
                amn->amn_success++;
                if (amn->amn_success == amn->amn_success_threshold &&
                    !is_max_rate (ni)) {
                        amn->amn_recovery = 1;
                        amn->amn_success = 0;
                        ni->ni_txrate++;
                        DPRINTF (sc, "increase rate to %d\n", ni->ni_txrate);
                } else {
                        amn->amn_recovery = 0;
                }
        } else if (is_failure (amn)) {
                amn->amn_success = 0;
                if (!is_min_rate (ni)) {
                        if (amn->amn_recovery) {
                                /* recovery failure. */
                                amn->amn_success_threshold *= 2;
                                amn->amn_success_threshold = min (amn->amn_success_threshold,
                                                                  (u_int)ath_rate_max_success_threshold);
                                DPRINTF (sc, "decrease rate recovery thr: %d\n", amn->amn_success_threshold);
                        } else {
                                /* simple failure. */
                                amn->amn_success_threshold = ath_rate_min_success_threshold;
                                DPRINTF (sc, "decrease rate normal thr: %d\n", amn->amn_success_threshold);
                        }
                        amn->amn_recovery = 0;
                        ni->ni_txrate--;
                } else {
                        amn->amn_recovery = 0;
                }

        }
        if (is_enough (amn) || old_rate != ni->ni_txrate) {
                /* reset counters. */
                amn->amn_tx_try0_cnt = 0;
                amn->amn_tx_try1_cnt = 0;
                amn->amn_tx_try2_cnt = 0;
                amn->amn_tx_try3_cnt = 0;
                amn->amn_tx_failure_cnt = 0;
        }
        if (old_rate != ni->ni_txrate) {
                ath_rate_update(sc, ni, ni->ni_txrate);
        }
}

static void
ath_ratectl(void *arg)
{
        struct ifnet *ifp = arg;
        struct ath_softc *sc = ifp->if_softc;
        struct amrr_softc *asc = (struct amrr_softc *) sc->sc_rc;
        struct ieee80211com *ic = &sc->sc_ic;
        int interval;

        if (ifp->if_drv_flags & IFF_DRV_RUNNING) {
                sc->sc_stats.ast_rate_calls++;

                if (ic->ic_opmode == IEEE80211_M_STA)
                        ath_rate_ctl(sc, ic->ic_bss);   /* NB: no reference */
                else
                        ieee80211_iterate_nodes(&ic->ic_sta, ath_rate_ctl, sc);
        }
        interval = ath_rateinterval;
        if (ic->ic_opmode == IEEE80211_M_STA)
                interval /= 2;
        callout_reset(&asc->timer, (interval * hz) / 1000,
                ath_ratectl, &sc->sc_if);
}

static void
ath_rate_sysctlattach(struct ath_softc *sc)
{
        struct sysctl_ctx_list *ctx = device_get_sysctl_ctx(sc->sc_dev);
        struct sysctl_oid *tree = device_get_sysctl_tree(sc->sc_dev);

        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "rate_interval", CTLFLAG_RW, &ath_rateinterval, 0,
                "rate control: operation interval (ms)");
        /* XXX bounds check values */
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "max_sucess_threshold", CTLFLAG_RW,
                &ath_rate_max_success_threshold, 0, "");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "min_sucess_threshold", CTLFLAG_RW,
                &ath_rate_min_success_threshold, 0, "");
}

struct ath_ratectrl *
ath_rate_attach(struct ath_softc *sc)
{
        struct amrr_softc *asc;

        asc = malloc(sizeof(struct amrr_softc), M_DEVBUF, M_WAITOK|M_ZERO);
        asc->arc.arc_space = sizeof(struct amrr_node);
        callout_init(&asc->timer, debug_mpsafenet ? CALLOUT_MPSAFE : 0);
        ath_rate_sysctlattach(sc);

        return &asc->arc;
}

void
ath_rate_detach(struct ath_ratectrl *arc)
{
        struct amrr_softc *asc = (struct amrr_softc *) arc;

        callout_drain(&asc->timer);
        free(asc, M_DEVBUF);
}