The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: 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: releng/11.0/sys/net80211/ieee80211_rssadapt.c 283538 2015-05-25 19:18:16Z adrian $    */
    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 (msecs < 100)
  122                 msecs = 100;
  123         t = msecs_to_ticks(msecs);
  124         rs->interval = (t < 1) ? 1 : t;
  125 }
  126 
  127 static void
  128 rssadapt_init(struct ieee80211vap *vap)
  129 {
  130         struct ieee80211_rssadapt *rs;
  131 
  132         KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
  133             __func__));
  134         
  135         vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
  136             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  137         if (rs == NULL) {
  138                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  139                 return;
  140         }
  141         rs->vap = vap;
  142         rssadapt_setinterval(vap, 500 /* msecs */);
  143         rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  144 }
  145 
  146 static void
  147 rssadapt_deinit(struct ieee80211vap *vap)
  148 {
  149         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
  150 }
  151 
  152 static void
  153 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
  154 {
  155         long interval;
  156 
  157         ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
  158         ra->ra_nfail = ra->ra_nok = 0;
  159 
  160         /*
  161          * A node is eligible for its rate to be raised every 1/10 to 10
  162          * seconds, more eligible in proportion to recent packet rates.
  163          */
  164         interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
  165         ra->ra_raise_interval = msecs_to_ticks(interval);
  166 }
  167 
  168 static void
  169 rssadapt_node_init(struct ieee80211_node *ni)
  170 {
  171         struct ieee80211_rssadapt_node *ra;
  172         struct ieee80211vap *vap = ni->ni_vap;
  173         struct ieee80211_rssadapt *rsa = vap->iv_rs;
  174         const struct ieee80211_rateset *rs = &ni->ni_rates;
  175 
  176         if (ni->ni_rctls == NULL) {
  177                 ni->ni_rctls = ra = 
  178                     IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
  179                         M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  180                 if (ra == NULL) {
  181                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  182                             "structure\n");
  183                         return;
  184                 }
  185         } else
  186                 ra = ni->ni_rctls;
  187         ra->ra_rs = rsa;
  188         ra->ra_rates = *rs;
  189         rssadapt_updatestats(ra);
  190 
  191         /* pick initial rate */
  192         for (ra->ra_rix = rs->rs_nrates - 1;
  193              ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
  194              ra->ra_rix--)
  195                 ;
  196         ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
  197         ra->ra_ticks = ticks;
  198 
  199         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  200             "RSSADAPT initial rate %d", ni->ni_txrate);
  201 }
  202 
  203 static void
  204 rssadapt_node_deinit(struct ieee80211_node *ni)
  205 {
  206 
  207         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
  208 }
  209 
  210 static __inline int
  211 bucket(int pktlen)
  212 {
  213         int i, top, thridx;
  214 
  215         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  216              i < IEEE80211_RSSADAPT_BKTS;
  217              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  218                 thridx = i;
  219                 if (pktlen <= top)
  220                         break;
  221         }
  222         return thridx;
  223 }
  224 
  225 static int
  226 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
  227 {
  228         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  229         u_int pktlen = iarg;
  230         const struct ieee80211_rateset *rs = &ra->ra_rates;
  231         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  232         int rix, rssi;
  233 
  234         if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
  235                 rssadapt_updatestats(ra);
  236                 ra->ra_ticks = ticks;
  237         }
  238 
  239         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  240 
  241         /* XXX this is average rssi, should be using last value */
  242         rssi = ni->ni_ic->ic_node_getrssi(ni);
  243         for (rix = rs->rs_nrates-1; rix >= 0; rix--)
  244                 if ((*thrs)[rix] < (rssi << 8))
  245                         break;
  246         if (rix != ra->ra_rix) {
  247                 /* update public rate */
  248                 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
  249                 ra->ra_rix = rix;
  250 
  251                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  252                     "RSSADAPT new rate %d (pktlen %d rssi %d)",
  253                     ni->ni_txrate, pktlen, rssi);
  254         }
  255         return rix;
  256 }
  257 
  258 /*
  259  * Adapt the data rate to suit the conditions.  When a transmitted
  260  * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
  261  * raise the RSS threshold for transmitting packets of similar length at
  262  * the same data rate.
  263  */
  264 static void
  265 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  266 {
  267         uint16_t last_thr;
  268         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  269         u_int rix;
  270 
  271         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  272 
  273         rix = ra->ra_rix;
  274         last_thr = (*thrs)[rix];
  275         (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
  276             last_thr, (rssi << 8));
  277 
  278         IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  279             "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
  280             ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  281             last_thr, (*thrs)[rix], rssi);
  282 }
  283 
  284 static void
  285 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  286 {
  287         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  288         uint16_t newthr, oldthr;
  289         int rix;
  290 
  291         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  292 
  293         rix = ra->ra_rix;
  294         if ((*thrs)[rix + 1] > (*thrs)[rix]) {
  295                 oldthr = (*thrs)[rix + 1];
  296                 if ((*thrs)[rix] == 0)
  297                         newthr = (rssi << 8);
  298                 else
  299                         newthr = (*thrs)[rix];
  300                 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
  301                     oldthr, newthr);
  302 
  303                 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  304                     "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
  305                     ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  306                     oldthr, newthr, rssi);
  307 
  308                 ra->ra_last_raise = ticks;
  309         }
  310 }
  311 
  312 static void
  313 rssadapt_tx_complete(const struct ieee80211vap *vap,
  314     const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
  315 {
  316         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  317         int pktlen = *(int *)arg1, rssi = *(int *)arg2;
  318 
  319         if (success) {
  320                 ra->ra_nok++;
  321                 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
  322                     (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
  323                         rssadapt_raise_rate(ra, pktlen, rssi);
  324         } else {
  325                 ra->ra_nfail++;
  326                 rssadapt_lower_rate(ra, pktlen, rssi);
  327         }
  328 }
  329 
  330 static int
  331 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
  332 {
  333         struct ieee80211vap *vap = arg1;
  334         struct ieee80211_rssadapt *rs = vap->iv_rs;
  335         int msecs = ticks_to_msecs(rs->interval);
  336         int error;
  337 
  338         error = sysctl_handle_int(oidp, &msecs, 0, req);
  339         if (error || !req->newptr)
  340                 return error;
  341         rssadapt_setinterval(vap, msecs);
  342         return 0;
  343 }
  344 
  345 static void
  346 rssadapt_sysctlattach(struct ieee80211vap *vap,
  347     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  348 {
  349 
  350         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  351             "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  352             0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
  353 }

Cache object: 4f5b72462b798b0a9606793a7b5eb57f


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