FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_rssadapt.c

     /*      $FreeBSD: releng/12.0/sys/net80211/ieee80211_rssadapt.c 326272 2017-11-27 15:23:17Z pfg $       */
     /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
     /*-
      * SPDX-License-Identifier: BSD-3-Clause
      *
      * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
      * Copyright (c) 2003, 2004 David Young.  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.
     * 3. The name of David Young may not be used to endorse or promote
     *    products derived from this software without specific prior
     *    written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY David Young ``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 David
     * Young 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 "opt_wlan.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/kernel.h>
    #include <sys/malloc.h>
    #include <sys/module.h>
    #include <sys/socket.h>
    #include <sys/sysctl.h>
    
    #include <net/if.h>
    #include <net/if_var.h>
    #include <net/if_media.h>
    #include <net/ethernet.h>
    
    #include <net80211/ieee80211_var.h>
    #include <net80211/ieee80211_rssadapt.h>
    #include <net80211/ieee80211_ratectl.h>
    
    struct rssadapt_expavgctl {
            /* RSS threshold decay. */
            u_int rc_decay_denom;
            u_int rc_decay_old;
            /* RSS threshold update. */
            u_int rc_thresh_denom;
            u_int rc_thresh_old;
            /* RSS average update. */
            u_int rc_avgrssi_denom;
            u_int rc_avgrssi_old;
    };
    
    static struct rssadapt_expavgctl master_expavgctl = {
            .rc_decay_denom = 16,
            .rc_decay_old = 15,
            .rc_thresh_denom = 8,
            .rc_thresh_old = 4,
            .rc_avgrssi_denom = 8,
            .rc_avgrssi_old = 4
    };
    
    #ifdef interpolate
    #undef interpolate
    #endif
    #define interpolate(parm, old, new) ((parm##_old * (old) + \
                                         (parm##_denom - parm##_old) * (new)) / \
                                        parm##_denom)
    
    static void     rssadapt_setinterval(const struct ieee80211vap *, int);
    static void     rssadapt_init(struct ieee80211vap *);
    static void     rssadapt_deinit(struct ieee80211vap *);
    static void     rssadapt_updatestats(struct ieee80211_rssadapt_node *);
    static void     rssadapt_node_init(struct ieee80211_node *);
    static void     rssadapt_node_deinit(struct ieee80211_node *);
    static int      rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
    static void     rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
    static void     rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
                            int, int);
    static void     rssadapt_tx_complete(const struct ieee80211_node *,
                            const struct ieee80211_ratectl_tx_status *);
    static void     rssadapt_sysctlattach(struct ieee80211vap *,
                            struct sysctl_ctx_list *, struct sysctl_oid *);
    
    /* number of references from net80211 layer */
    static  int nrefs = 0;
    
   static const struct ieee80211_ratectl rssadapt = {
           .ir_name        = "rssadapt",
           .ir_attach      = NULL,
           .ir_detach      = NULL,
           .ir_init        = rssadapt_init,
           .ir_deinit      = rssadapt_deinit,
           .ir_node_init   = rssadapt_node_init,
           .ir_node_deinit = rssadapt_node_deinit,
           .ir_rate        = rssadapt_rate,
           .ir_tx_complete = rssadapt_tx_complete,
           .ir_tx_update   = NULL,
           .ir_setinterval = rssadapt_setinterval,
   };
   IEEE80211_RATECTL_MODULE(rssadapt, 1);
   IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
   
   static void
   rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
   {
           struct ieee80211_rssadapt *rs = vap->iv_rs;
           int t;
   
           if (msecs < 100)
                   msecs = 100;
           t = msecs_to_ticks(msecs);
           rs->interval = (t < 1) ? 1 : t;
   }
   
   static void
   rssadapt_init(struct ieee80211vap *vap)
   {
           struct ieee80211_rssadapt *rs;
   
           KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
               __func__));
   
           nrefs++;                /* XXX locking */
           vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
               M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
           if (rs == NULL) {
                   if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
                   return;
           }
           rs->vap = vap;
           rssadapt_setinterval(vap, 500 /* msecs */);
           rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
   }
   
   static void
   rssadapt_deinit(struct ieee80211vap *vap)
   {
           IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
           KASSERT(nrefs > 0, ("imbalanced attach/detach"));
           nrefs--;                /* XXX locking */
   }
   
   static void
   rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
   {
           long interval;
   
           ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
           ra->ra_nfail = ra->ra_nok = 0;
   
           /*
            * A node is eligible for its rate to be raised every 1/10 to 10
            * seconds, more eligible in proportion to recent packet rates.
            */
           interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
           ra->ra_raise_interval = msecs_to_ticks(interval);
   }
   
   static void
   rssadapt_node_init(struct ieee80211_node *ni)
   {
           struct ieee80211_rssadapt_node *ra;
           struct ieee80211vap *vap = ni->ni_vap;
           struct ieee80211_rssadapt *rsa = vap->iv_rs;
           const struct ieee80211_rateset *rs = &ni->ni_rates;
   
           if (ni->ni_rctls == NULL) {
                   ni->ni_rctls = ra = 
                       IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
                           M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
                   if (ra == NULL) {
                           if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
                               "structure\n");
                           return;
                   }
           } else
                   ra = ni->ni_rctls;
           ra->ra_rs = rsa;
           ra->ra_rates = *rs;
           rssadapt_updatestats(ra);
   
           /* pick initial rate */
           for (ra->ra_rix = rs->rs_nrates - 1;
                ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
                ra->ra_rix--)
                   ;
           ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
           ra->ra_ticks = ticks;
   
           IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
               "RSSADAPT initial rate %d", ni->ni_txrate);
   }
   
   static void
   rssadapt_node_deinit(struct ieee80211_node *ni)
   {
   
           IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
   }
   
   static __inline int
   bucket(int pktlen)
   {
           int i, top, thridx;
   
           for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
                i < IEEE80211_RSSADAPT_BKTS;
                i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
                   thridx = i;
                   if (pktlen <= top)
                           break;
           }
           return thridx;
   }
   
   static int
   rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
   {
           struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
           u_int pktlen = iarg;
           const struct ieee80211_rateset *rs = &ra->ra_rates;
           uint16_t (*thrs)[IEEE80211_RATE_SIZE];
           int rix, rssi;
   
           if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
                   rssadapt_updatestats(ra);
                   ra->ra_ticks = ticks;
           }
   
           thrs = &ra->ra_rate_thresh[bucket(pktlen)];
   
           /* XXX this is average rssi, should be using last value */
           rssi = ni->ni_ic->ic_node_getrssi(ni);
           for (rix = rs->rs_nrates-1; rix >= 0; rix--)
                   if ((*thrs)[rix] < (rssi << 8))
                           break;
           if (rix != ra->ra_rix) {
                   /* update public rate */
                   ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
                   ra->ra_rix = rix;
   
                   IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
                       "RSSADAPT new rate %d (pktlen %d rssi %d)",
                       ni->ni_txrate, pktlen, rssi);
           }
           return rix;
   }
   
   /*
    * Adapt the data rate to suit the conditions.  When a transmitted
    * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
    * raise the RSS threshold for transmitting packets of similar length at
    * the same data rate.
    */
   static void
   rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
   {
           uint16_t last_thr;
           uint16_t (*thrs)[IEEE80211_RATE_SIZE];
           u_int rix;
   
           thrs = &ra->ra_rate_thresh[bucket(pktlen)];
   
           rix = ra->ra_rix;
           last_thr = (*thrs)[rix];
           (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
               last_thr, (rssi << 8));
   
           IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
               "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
               ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
               last_thr, (*thrs)[rix], rssi);
   }
   
   static void
   rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
   {
           uint16_t (*thrs)[IEEE80211_RATE_SIZE];
           uint16_t newthr, oldthr;
           int rix;
   
           thrs = &ra->ra_rate_thresh[bucket(pktlen)];
   
           rix = ra->ra_rix;
           if ((*thrs)[rix + 1] > (*thrs)[rix]) {
                   oldthr = (*thrs)[rix + 1];
                   if ((*thrs)[rix] == 0)
                           newthr = (rssi << 8);
                   else
                           newthr = (*thrs)[rix];
                   (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
                       oldthr, newthr);
   
                   IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
                       "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
                       ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
                       oldthr, newthr, rssi);
   
                   ra->ra_last_raise = ticks;
           }
   }
   
   static void
   rssadapt_tx_complete(const struct ieee80211_node *ni,
       const struct ieee80211_ratectl_tx_status *status)
   {
           struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
           int pktlen, rssi;
   
           if ((status->flags &
               (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI)) !=
               (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI))
                   return;
   
           pktlen = status->pktlen;
           rssi = status->rssi;
   
           if (status->status == IEEE80211_RATECTL_TX_SUCCESS) {
                   ra->ra_nok++;
                   if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
                       (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
                           rssadapt_raise_rate(ra, pktlen, rssi);
           } else {
                   ra->ra_nfail++;
                   rssadapt_lower_rate(ra, pktlen, rssi);
           }
   }
   
   static int
   rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
   {
           struct ieee80211vap *vap = arg1;
           struct ieee80211_rssadapt *rs = vap->iv_rs;
           int msecs = ticks_to_msecs(rs->interval);
           int error;
   
           error = sysctl_handle_int(oidp, &msecs, 0, req);
           if (error || !req->newptr)
                   return error;
           rssadapt_setinterval(vap, msecs);
           return 0;
   }
   
   static void
   rssadapt_sysctlattach(struct ieee80211vap *vap,
       struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
   {
   
           SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
               "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
               0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
   }

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