The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_rssadapt.c

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    1 /*      $FreeBSD: stable/11/sys/net80211/ieee80211_rssadapt.c 343035 2019-01-15 02:16:23Z avos $        */
    2 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
    3 /*-
    4  * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
    5  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
    6  *
    7  * Redistribution and use in source and binary forms, with or
    8  * without modification, are permitted provided that the following
    9  * conditions are met:
   10  * 1. Redistributions of source code must retain the above copyright
   11  *    notice, this list of conditions and the following disclaimer.
   12  * 2. Redistributions in binary form must reproduce the above
   13  *    copyright notice, this list of conditions and the following
   14  *    disclaimer in the documentation and/or other materials provided
   15  *    with the distribution.
   16  * 3. The name of David Young may not be used to endorse or promote
   17  *    products derived from this software without specific prior
   18  *    written permission.
   19  *
   20  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
   21  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   22  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   23  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
   24  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   25  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
   26  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   28  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   29  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   31  * OF SUCH DAMAGE.
   32  */
   33 #include "opt_wlan.h"
   34 
   35 #include <sys/param.h>
   36 #include <sys/systm.h>
   37 #include <sys/kernel.h>
   38 #include <sys/malloc.h>
   39 #include <sys/module.h>
   40 #include <sys/socket.h>
   41 #include <sys/sysctl.h>
   42 
   43 #include <net/if.h>
   44 #include <net/if_var.h>
   45 #include <net/if_media.h>
   46 #include <net/ethernet.h>
   47 
   48 #include <net80211/ieee80211_var.h>
   49 #include <net80211/ieee80211_rssadapt.h>
   50 #include <net80211/ieee80211_ratectl.h>
   51 
   52 struct rssadapt_expavgctl {
   53         /* RSS threshold decay. */
   54         u_int rc_decay_denom;
   55         u_int rc_decay_old;
   56         /* RSS threshold update. */
   57         u_int rc_thresh_denom;
   58         u_int rc_thresh_old;
   59         /* RSS average update. */
   60         u_int rc_avgrssi_denom;
   61         u_int rc_avgrssi_old;
   62 };
   63 
   64 static struct rssadapt_expavgctl master_expavgctl = {
   65         .rc_decay_denom = 16,
   66         .rc_decay_old = 15,
   67         .rc_thresh_denom = 8,
   68         .rc_thresh_old = 4,
   69         .rc_avgrssi_denom = 8,
   70         .rc_avgrssi_old = 4
   71 };
   72 
   73 #ifdef interpolate
   74 #undef interpolate
   75 #endif
   76 #define interpolate(parm, old, new) ((parm##_old * (old) + \
   77                                      (parm##_denom - parm##_old) * (new)) / \
   78                                     parm##_denom)
   79 
   80 static void     rssadapt_setinterval(const struct ieee80211vap *, int);
   81 static void     rssadapt_init(struct ieee80211vap *);
   82 static void     rssadapt_deinit(struct ieee80211vap *);
   83 static void     rssadapt_updatestats(struct ieee80211_rssadapt_node *);
   84 static void     rssadapt_node_init(struct ieee80211_node *);
   85 static void     rssadapt_node_deinit(struct ieee80211_node *);
   86 static int      rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
   87 static void     rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
   88 static void     rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
   89                         int, int);
   90 static void     rssadapt_tx_complete(const struct ieee80211vap *,
   91                         const struct ieee80211_node *, int,
   92                         void *, void *);
   93 static void     rssadapt_sysctlattach(struct ieee80211vap *,
   94                         struct sysctl_ctx_list *, struct sysctl_oid *);
   95 
   96 /* number of references from net80211 layer */
   97 static  int nrefs = 0;
   98 
   99 static const struct ieee80211_ratectl rssadapt = {
  100         .ir_name        = "rssadapt",
  101         .ir_attach      = NULL,
  102         .ir_detach      = NULL,
  103         .ir_init        = rssadapt_init,
  104         .ir_deinit      = rssadapt_deinit,
  105         .ir_node_init   = rssadapt_node_init,
  106         .ir_node_deinit = rssadapt_node_deinit,
  107         .ir_rate        = rssadapt_rate,
  108         .ir_tx_complete = rssadapt_tx_complete,
  109         .ir_tx_update   = NULL,
  110         .ir_setinterval = rssadapt_setinterval,
  111 };
  112 IEEE80211_RATECTL_MODULE(rssadapt, 1);
  113 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
  114 
  115 static void
  116 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
  117 {
  118         struct ieee80211_rssadapt *rs = vap->iv_rs;
  119         int t;
  120 
  121         if (!rs)
  122                 return;
  123 
  124         if (msecs < 100)
  125                 msecs = 100;
  126         t = msecs_to_ticks(msecs);
  127         rs->interval = (t < 1) ? 1 : t;
  128 }
  129 
  130 static void
  131 rssadapt_init(struct ieee80211vap *vap)
  132 {
  133         struct ieee80211_rssadapt *rs;
  134 
  135         KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
  136             __func__));
  137 
  138         nrefs++;                /* XXX locking */
  139         vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
  140             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  141         if (rs == NULL) {
  142                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  143                 return;
  144         }
  145         rs->vap = vap;
  146         rssadapt_setinterval(vap, 500 /* msecs */);
  147         rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  148 }
  149 
  150 static void
  151 rssadapt_deinit(struct ieee80211vap *vap)
  152 {
  153         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
  154         KASSERT(nrefs > 0, ("imbalanced attach/detach"));
  155         nrefs--;                /* XXX locking */
  156 }
  157 
  158 static void
  159 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
  160 {
  161         long interval;
  162 
  163         ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
  164         ra->ra_nfail = ra->ra_nok = 0;
  165 
  166         /*
  167          * A node is eligible for its rate to be raised every 1/10 to 10
  168          * seconds, more eligible in proportion to recent packet rates.
  169          */
  170         interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
  171         ra->ra_raise_interval = msecs_to_ticks(interval);
  172 }
  173 
  174 static void
  175 rssadapt_node_init(struct ieee80211_node *ni)
  176 {
  177         struct ieee80211_rssadapt_node *ra;
  178         struct ieee80211vap *vap = ni->ni_vap;
  179         struct ieee80211_rssadapt *rsa = vap->iv_rs;
  180         const struct ieee80211_rateset *rs = &ni->ni_rates;
  181 
  182         if (!rsa) {
  183                 if_printf(vap->iv_ifp, "ratectl structure was not allocated, "
  184                     "per-node structure allocation skipped\n");
  185                 return;
  186         }
  187 
  188         if (ni->ni_rctls == NULL) {
  189                 ni->ni_rctls = ra = 
  190                     IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
  191                         M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  192                 if (ra == NULL) {
  193                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  194                             "structure\n");
  195                         return;
  196                 }
  197         } else
  198                 ra = ni->ni_rctls;
  199         ra->ra_rs = rsa;
  200         ra->ra_rates = *rs;
  201         rssadapt_updatestats(ra);
  202 
  203         /* pick initial rate */
  204         for (ra->ra_rix = rs->rs_nrates - 1;
  205              ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
  206              ra->ra_rix--)
  207                 ;
  208         ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
  209         ra->ra_ticks = ticks;
  210 
  211         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  212             "RSSADAPT initial rate %d", ni->ni_txrate);
  213 }
  214 
  215 static void
  216 rssadapt_node_deinit(struct ieee80211_node *ni)
  217 {
  218 
  219         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
  220 }
  221 
  222 static __inline int
  223 bucket(int pktlen)
  224 {
  225         int i, top, thridx;
  226 
  227         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  228              i < IEEE80211_RSSADAPT_BKTS;
  229              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  230                 thridx = i;
  231                 if (pktlen <= top)
  232                         break;
  233         }
  234         return thridx;
  235 }
  236 
  237 static int
  238 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
  239 {
  240         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  241         u_int pktlen = iarg;
  242         const struct ieee80211_rateset *rs;
  243         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  244         int rix, rssi;
  245 
  246         /* XXX should return -1 here, but drivers may not expect this... */
  247         if (!ra)
  248         {
  249                 ni->ni_txrate = ni->ni_rates.rs_rates[0];
  250                 return 0;
  251         }
  252 
  253         rs = &ra->ra_rates;
  254         if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
  255                 rssadapt_updatestats(ra);
  256                 ra->ra_ticks = ticks;
  257         }
  258 
  259         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  260 
  261         /* XXX this is average rssi, should be using last value */
  262         rssi = ni->ni_ic->ic_node_getrssi(ni);
  263         for (rix = rs->rs_nrates-1; rix >= 0; rix--)
  264                 if ((*thrs)[rix] < (rssi << 8))
  265                         break;
  266         if (rix != ra->ra_rix) {
  267                 /* update public rate */
  268                 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
  269                 ra->ra_rix = rix;
  270 
  271                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  272                     "RSSADAPT new rate %d (pktlen %d rssi %d)",
  273                     ni->ni_txrate, pktlen, rssi);
  274         }
  275         return rix;
  276 }
  277 
  278 /*
  279  * Adapt the data rate to suit the conditions.  When a transmitted
  280  * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
  281  * raise the RSS threshold for transmitting packets of similar length at
  282  * the same data rate.
  283  */
  284 static void
  285 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  286 {
  287         uint16_t last_thr;
  288         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  289         u_int rix;
  290 
  291         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  292 
  293         rix = ra->ra_rix;
  294         last_thr = (*thrs)[rix];
  295         (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
  296             last_thr, (rssi << 8));
  297 
  298         IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  299             "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
  300             ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  301             last_thr, (*thrs)[rix], rssi);
  302 }
  303 
  304 static void
  305 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  306 {
  307         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  308         uint16_t newthr, oldthr;
  309         int rix;
  310 
  311         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  312 
  313         rix = ra->ra_rix;
  314         if ((*thrs)[rix + 1] > (*thrs)[rix]) {
  315                 oldthr = (*thrs)[rix + 1];
  316                 if ((*thrs)[rix] == 0)
  317                         newthr = (rssi << 8);
  318                 else
  319                         newthr = (*thrs)[rix];
  320                 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
  321                     oldthr, newthr);
  322 
  323                 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  324                     "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
  325                     ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  326                     oldthr, newthr, rssi);
  327 
  328                 ra->ra_last_raise = ticks;
  329         }
  330 }
  331 
  332 static void
  333 rssadapt_tx_complete(const struct ieee80211vap *vap,
  334     const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
  335 {
  336         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  337         int pktlen = *(int *)arg1, rssi = *(int *)arg2;
  338 
  339         if (!ra)
  340                 return;
  341 
  342         if (success) {
  343                 ra->ra_nok++;
  344                 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
  345                     (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
  346                         rssadapt_raise_rate(ra, pktlen, rssi);
  347         } else {
  348                 ra->ra_nfail++;
  349                 rssadapt_lower_rate(ra, pktlen, rssi);
  350         }
  351 }
  352 
  353 static int
  354 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
  355 {
  356         struct ieee80211vap *vap = arg1;
  357         struct ieee80211_rssadapt *rs = vap->iv_rs;
  358         int msecs, error;
  359 
  360         if (!rs)
  361                 return ENOMEM;
  362 
  363         msecs = ticks_to_msecs(rs->interval);
  364         error = sysctl_handle_int(oidp, &msecs, 0, req);
  365         if (error || !req->newptr)
  366                 return error;
  367         rssadapt_setinterval(vap, msecs);
  368         return 0;
  369 }
  370 
  371 static void
  372 rssadapt_sysctlattach(struct ieee80211vap *vap,
  373     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  374 {
  375 
  376         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  377             "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  378             0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
  379 }

Cache object: 88e2d88e7c2b856a90a54913913f3d09


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