/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2002-2007 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.
 *
 * 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>
/*
 * Atsushi Onoe's rate control algorithm.
 */
#include "opt_ath.h"
#include "opt_inet.h"
#include "opt_wlan.h"

#include <sys/param.h>
#include <sys/systm.h> 
#include <sys/sysctl.h>
#include <sys/kernel.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/errno.h>

#include <machine/bus.h>
#include <machine/resource.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/ethernet.h>               /* XXX for ether_sprintf */

#include <net80211/ieee80211_var.h>

#include <net/bpf.h>

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

#include <dev/ath/if_athvar.h>
#include <dev/ath/ath_rate/onoe/onoe.h>
#include <dev/ath/ath_hal/ah_desc.h>

/*
 * Default parameters for the rate control algorithm.  These are
 * all tunable with sysctls.  The rate controller runs periodically
 * (each ath_rateinterval ms) analyzing transmit statistics for each
 * neighbor/station (when operating in station mode this is only the AP).
 * If transmits look to be working well over a sampling period then
 * it gives a "raise rate credit".  If transmits look to not be working
 * well than it deducts a credit.  If the credits cross a threshold then
 * the transmit rate is raised.  Various error conditions force the
 * the transmit rate to be dropped.
 *
 * The decision to issue/deduct a credit is based on the errors and
 * retries accumulated over the sampling period.  ath_rate_raise defines
 * the percent of retransmits for which a credit is issued/deducted.
 * ath_rate_raise_threshold defines the threshold on credits at which
 * the transmit rate is increased.
 *
 * XXX this algorithm is flawed.
 */
static  int ath_rateinterval = 1000;            /* rate ctl interval (ms)  */
static  int ath_rate_raise = 10;                /* add credit threshold */
static  int ath_rate_raise_threshold = 10;      /* rate ctl raise threshold */

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 */
}

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, int tid, int is_aggr,
        u_int8_t *rix, int *try0, u_int8_t *txrate, int *maxdur,
        int *maxpktlen)
{
        struct onoe_node *on = ATH_NODE_ONOE(an);

        *rix = on->on_tx_rix0;
        *try0 = on->on_tx_try0;
        if (shortPreamble)
                *txrate = on->on_tx_rate0sp;
        else
                *txrate = on->on_tx_rate0;
        *maxdur = -1;
        *maxpktlen = -1;
}

/*
 * Get the TX rates.
 *
 * The short preamble bits aren't set here; the caller should augment
 * the returned rate with the relevant preamble rate flag.
 */
void
ath_rate_getxtxrates(struct ath_softc *sc, struct ath_node *an,
    uint8_t rix0, int is_aggr, struct ath_rc_series *rc)
{
        struct onoe_node *on = ATH_NODE_ONOE(an);

        rc[0].flags = rc[1].flags = rc[2].flags = rc[3].flags = 0;

        rc[0].rix = on->on_tx_rate0;
        rc[1].rix = on->on_tx_rate1;
        rc[2].rix = on->on_tx_rate2;
        rc[3].rix = on->on_tx_rate3;

        rc[0].tries = on->on_tx_try0;
        rc[1].tries = 2;
        rc[2].tries = 2;
        rc[3].tries = 2;
}

void
ath_rate_setupxtxdesc(struct ath_softc *sc, struct ath_node *an,
        struct ath_desc *ds, int shortPreamble, u_int8_t rix)
{
        struct onoe_node *on = ATH_NODE_ONOE(an);

        ath_hal_setupxtxdesc(sc->sc_ah, ds
                , on->on_tx_rate1sp, 2  /* series 1 */
                , on->on_tx_rate2sp, 2  /* series 2 */
                , on->on_tx_rate3sp, 2  /* series 3 */
        );
}

void
ath_rate_tx_complete(struct ath_softc *sc, struct ath_node *an,
        const struct ath_rc_series *rc, const struct ath_tx_status *ts,
        int frame_size, int rc_framesize, int nframes, int nbad)
{
        struct onoe_node *on = ATH_NODE_ONOE(an);

        if (ts->ts_status == 0)
                on->on_tx_ok++;
        else
                on->on_tx_err++;
        on->on_tx_retr += ts->ts_shortretry
                        + ts->ts_longretry;
        if (on->on_interval != 0 && ticks - on->on_ticks > on->on_interval) {
                ath_rate_ctl(sc, &an->an_node);
                on->on_ticks = ticks;
        }
}

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

void
ath_rate_update_rx_rssi(struct ath_softc *sc, struct ath_node *an, int rssi)
{
}

static void
ath_rate_update(struct ath_softc *sc, struct ieee80211_node *ni, int rate)
{
        struct ath_node *an = ATH_NODE(ni);
        struct onoe_node *on = ATH_NODE_ONOE(an);
        struct ieee80211vap *vap = ni->ni_vap;
        const HAL_RATE_TABLE *rt = sc->sc_currates;
        u_int8_t rix;
        uint8_t dot11rate;

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

        IEEE80211_NOTE(vap, IEEE80211_MSG_RATECTL, ni,
             "%s: set xmit rate to %dM", __func__,
             ni->ni_rates.rs_nrates > 0 ?
                (ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL) / 2 : 0);

        /*
         * 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)
                goto done;
        on->on_rix = rate;
        dot11rate = ni->ni_rates.rs_rates[rate] & IEEE80211_RATE_VAL;
        ieee80211_node_set_txrate_dot11rate(ni, dot11rate);
        on->on_tx_rix0 = sc->sc_rixmap[dot11rate];
        on->on_tx_rate0 = rt->info[on->on_tx_rix0].rateCode;

        on->on_tx_rate0sp = on->on_tx_rate0 |
                rt->info[on->on_tx_rix0].shortPreamble;
        if (sc->sc_mrretry) {
                /*
                 * Hardware supports multi-rate retry; setup two
                 * step-down retry rates and make the lowest rate
                 * be the ``last chance''.  We use 4, 2, 2, 2 tries
                 * respectively (4 is set here, the rest are fixed
                 * in the xmit routine).
                 */
                on->on_tx_try0 = 1 + 3;         /* 4 tries at rate 0 */
                if (--rate >= 0) {
                        rix = sc->sc_rixmap[
                                ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
                        on->on_tx_rate1 = rt->info[rix].rateCode;
                        on->on_tx_rate1sp = on->on_tx_rate1 |
                                rt->info[rix].shortPreamble;
                } else {
                        on->on_tx_rate1 = on->on_tx_rate1sp = 0;
                }
                if (--rate >= 0) {
                        rix = sc->sc_rixmap[
                                ni->ni_rates.rs_rates[rate]&IEEE80211_RATE_VAL];
                        on->on_tx_rate2 = rt->info[rix].rateCode;
                        on->on_tx_rate2sp = on->on_tx_rate2 |
                                rt->info[rix].shortPreamble;
                } else {
                        on->on_tx_rate2 = on->on_tx_rate2sp = 0;
                }
                if (rate > 0) {
                        /* NB: only do this if we didn't already do it above */
                        on->on_tx_rate3 = rt->info[0].rateCode;
                        on->on_tx_rate3sp =
                                on->on_tx_rate3 | rt->info[0].shortPreamble;
                } else {
                        on->on_tx_rate3 = on->on_tx_rate3sp = 0;
                }
        } else {
                on->on_tx_try0 = ATH_TXMAXTRY;  /* max tries at rate 0 */
                on->on_tx_rate1 = on->on_tx_rate1sp = 0;
                on->on_tx_rate2 = on->on_tx_rate2sp = 0;
                on->on_tx_rate3 = on->on_tx_rate3sp = 0;
        }
done:
        on->on_tx_ok = on->on_tx_err = on->on_tx_retr = on->on_tx_upper = 0;

        on->on_interval = ath_rateinterval;
        if (vap->iv_opmode == IEEE80211_M_STA)
                on->on_interval /= 2;
        on->on_interval = (on->on_interval * hz) / 1000;
}

/*
 * 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)
        const struct ieee80211_txparam *tp = ni->ni_txparms;
        int srate;

        KASSERT(ni->ni_rates.rs_nrates > 0, ("no rates"));
        if (tp == NULL || tp->ucastrate == 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--)
                                ;
                }
        } else {
                /*
                 * A fixed rate is to be used; ic_fixed_rate is the
                 * IEEE code for this rate (sans basic bit).  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.
                 */
                /* NB: the rate set is assumed sorted */
                srate = ni->ni_rates.rs_nrates - 1;
                for (; srate >= 0 && RATE(srate) != tp->ucastrate; srate--)
                        ;
        }
        /*
         * The selected rate may not be available due to races
         * and mode settings.  Also orphaned nodes created in
         * adhoc mode may not have any rate set so this lookup
         * can fail.  This is not fatal.
         */
        ath_rate_update(sc, ni, srate < 0 ? 0 : srate);
#undef RATE
}

/* 
 * Examine and potentially adjust the transmit rate.
 */
static void
ath_rate_ctl(void *arg, struct ieee80211_node *ni)
{
        struct ath_softc *sc = arg;
        struct onoe_node *on = ATH_NODE_ONOE(ATH_NODE(ni));
        struct ieee80211_rateset *rs = &ni->ni_rates;
        int dir = 0, nrate, enough;

        /*
         * Rate control
         * XXX: very primitive version.
         */
        enough = (on->on_tx_ok + on->on_tx_err >= 10);

        /* no packet reached -> down */
        if (on->on_tx_err > 0 && on->on_tx_ok == 0)
                dir = -1;

        /* all packets needs retry in average -> down */
        if (enough && on->on_tx_ok < on->on_tx_retr)
                dir = -1;

        /* no error and less than rate_raise% of packets need retry -> up */
        if (enough && on->on_tx_err == 0 &&
            on->on_tx_retr < (on->on_tx_ok * ath_rate_raise) / 100)
                dir = 1;

        IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
            "ok %d err %d retr %d upper %d dir %d",
            on->on_tx_ok, on->on_tx_err, on->on_tx_retr, on->on_tx_upper, dir);

        nrate = on->on_rix;
        switch (dir) {
        case 0:
                if (enough && on->on_tx_upper > 0)
                        on->on_tx_upper--;
                break;
        case -1:
                if (nrate > 0) {
                        nrate--;
                        sc->sc_stats.ast_rate_drop++;
                }
                on->on_tx_upper = 0;
                break;
        case 1:
                /* raise rate if we hit rate_raise_threshold */
                if (++on->on_tx_upper < ath_rate_raise_threshold)
                        break;
                on->on_tx_upper = 0;
                if (nrate + 1 < rs->rs_nrates) {
                        nrate++;
                        sc->sc_stats.ast_rate_raise++;
                }
                break;
        }

        if (nrate != on->on_rix) {
                IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
                    "%s: %dM -> %dM (%d ok, %d err, %d retr)", __func__,
                    ieee80211_node_get_txrate_kbit(ni) / 1000,
                    (rs->rs_rates[nrate] & IEEE80211_RATE_VAL) / 2,
                    on->on_tx_ok, on->on_tx_err, on->on_tx_retr);
                ath_rate_update(sc, ni, nrate);
        } else if (enough)
                on->on_tx_ok = on->on_tx_err = on->on_tx_retr = 0;
}

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,
                "rate_raise", CTLFLAG_RW, &ath_rate_raise, 0,
                "rate control: retry threshold to credit rate raise (%%)");
        SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
                "rate_raise_threshold", CTLFLAG_RW, &ath_rate_raise_threshold,0,
                "rate control: # good periods before raising rate");
}

static int
ath_rate_fetch_node_stats(struct ath_softc *sc, struct ath_node *an,
    struct ath_rateioctl *re)
{

        return (EINVAL);
}

struct ath_ratectrl *
ath_rate_attach(struct ath_softc *sc)
{
        struct onoe_softc *osc;

        osc = malloc(sizeof(struct onoe_softc), M_DEVBUF, M_NOWAIT|M_ZERO);
        if (osc == NULL)
                return NULL;
        osc->arc.arc_space = sizeof(struct onoe_node);
        ath_rate_sysctlattach(sc);

        return &osc->arc;
}

void
ath_rate_detach(struct ath_ratectrl *arc)
{
        struct onoe_softc *osc = (struct onoe_softc *) arc;

        free(osc, M_DEVBUF);
}