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/12.0/sys/net80211/ieee80211_rssadapt.c 326272 2017-11-27 15:23:17Z pfg $       */
    2 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
    3 /*-
    4  * SPDX-License-Identifier: BSD-3-Clause
    5  *
    6  * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
    7  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
    8  *
    9  * Redistribution and use in source and binary forms, with or
   10  * without modification, are permitted provided that the following
   11  * conditions are met:
   12  * 1. Redistributions of source code must retain the above copyright
   13  *    notice, this list of conditions and the following disclaimer.
   14  * 2. Redistributions in binary form must reproduce the above
   15  *    copyright notice, this list of conditions and the following
   16  *    disclaimer in the documentation and/or other materials provided
   17  *    with the distribution.
   18  * 3. The name of David Young may not be used to endorse or promote
   19  *    products derived from this software without specific prior
   20  *    written permission.
   21  *
   22  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
   23  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   24  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   25  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
   26  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   27  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
   28  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   29  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   30  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   33  * OF SUCH DAMAGE.
   34  */
   35 #include "opt_wlan.h"
   36 
   37 #include <sys/param.h>
   38 #include <sys/systm.h>
   39 #include <sys/kernel.h>
   40 #include <sys/malloc.h>
   41 #include <sys/module.h>
   42 #include <sys/socket.h>
   43 #include <sys/sysctl.h>
   44 
   45 #include <net/if.h>
   46 #include <net/if_var.h>
   47 #include <net/if_media.h>
   48 #include <net/ethernet.h>
   49 
   50 #include <net80211/ieee80211_var.h>
   51 #include <net80211/ieee80211_rssadapt.h>
   52 #include <net80211/ieee80211_ratectl.h>
   53 
   54 struct rssadapt_expavgctl {
   55         /* RSS threshold decay. */
   56         u_int rc_decay_denom;
   57         u_int rc_decay_old;
   58         /* RSS threshold update. */
   59         u_int rc_thresh_denom;
   60         u_int rc_thresh_old;
   61         /* RSS average update. */
   62         u_int rc_avgrssi_denom;
   63         u_int rc_avgrssi_old;
   64 };
   65 
   66 static struct rssadapt_expavgctl master_expavgctl = {
   67         .rc_decay_denom = 16,
   68         .rc_decay_old = 15,
   69         .rc_thresh_denom = 8,
   70         .rc_thresh_old = 4,
   71         .rc_avgrssi_denom = 8,
   72         .rc_avgrssi_old = 4
   73 };
   74 
   75 #ifdef interpolate
   76 #undef interpolate
   77 #endif
   78 #define interpolate(parm, old, new) ((parm##_old * (old) + \
   79                                      (parm##_denom - parm##_old) * (new)) / \
   80                                     parm##_denom)
   81 
   82 static void     rssadapt_setinterval(const struct ieee80211vap *, int);
   83 static void     rssadapt_init(struct ieee80211vap *);
   84 static void     rssadapt_deinit(struct ieee80211vap *);
   85 static void     rssadapt_updatestats(struct ieee80211_rssadapt_node *);
   86 static void     rssadapt_node_init(struct ieee80211_node *);
   87 static void     rssadapt_node_deinit(struct ieee80211_node *);
   88 static int      rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
   89 static void     rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
   90 static void     rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
   91                         int, int);
   92 static void     rssadapt_tx_complete(const struct ieee80211_node *,
   93                         const struct ieee80211_ratectl_tx_status *);
   94 static void     rssadapt_sysctlattach(struct ieee80211vap *,
   95                         struct sysctl_ctx_list *, struct sysctl_oid *);
   96 
   97 /* number of references from net80211 layer */
   98 static  int nrefs = 0;
   99 
  100 static const struct ieee80211_ratectl rssadapt = {
  101         .ir_name        = "rssadapt",
  102         .ir_attach      = NULL,
  103         .ir_detach      = NULL,
  104         .ir_init        = rssadapt_init,
  105         .ir_deinit      = rssadapt_deinit,
  106         .ir_node_init   = rssadapt_node_init,
  107         .ir_node_deinit = rssadapt_node_deinit,
  108         .ir_rate        = rssadapt_rate,
  109         .ir_tx_complete = rssadapt_tx_complete,
  110         .ir_tx_update   = NULL,
  111         .ir_setinterval = rssadapt_setinterval,
  112 };
  113 IEEE80211_RATECTL_MODULE(rssadapt, 1);
  114 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
  115 
  116 static void
  117 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
  118 {
  119         struct ieee80211_rssadapt *rs = vap->iv_rs;
  120         int t;
  121 
  122         if (msecs < 100)
  123                 msecs = 100;
  124         t = msecs_to_ticks(msecs);
  125         rs->interval = (t < 1) ? 1 : t;
  126 }
  127 
  128 static void
  129 rssadapt_init(struct ieee80211vap *vap)
  130 {
  131         struct ieee80211_rssadapt *rs;
  132 
  133         KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
  134             __func__));
  135 
  136         nrefs++;                /* XXX locking */
  137         vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
  138             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  139         if (rs == NULL) {
  140                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  141                 return;
  142         }
  143         rs->vap = vap;
  144         rssadapt_setinterval(vap, 500 /* msecs */);
  145         rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  146 }
  147 
  148 static void
  149 rssadapt_deinit(struct ieee80211vap *vap)
  150 {
  151         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
  152         KASSERT(nrefs > 0, ("imbalanced attach/detach"));
  153         nrefs--;                /* XXX locking */
  154 }
  155 
  156 static void
  157 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
  158 {
  159         long interval;
  160 
  161         ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
  162         ra->ra_nfail = ra->ra_nok = 0;
  163 
  164         /*
  165          * A node is eligible for its rate to be raised every 1/10 to 10
  166          * seconds, more eligible in proportion to recent packet rates.
  167          */
  168         interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
  169         ra->ra_raise_interval = msecs_to_ticks(interval);
  170 }
  171 
  172 static void
  173 rssadapt_node_init(struct ieee80211_node *ni)
  174 {
  175         struct ieee80211_rssadapt_node *ra;
  176         struct ieee80211vap *vap = ni->ni_vap;
  177         struct ieee80211_rssadapt *rsa = vap->iv_rs;
  178         const struct ieee80211_rateset *rs = &ni->ni_rates;
  179 
  180         if (ni->ni_rctls == NULL) {
  181                 ni->ni_rctls = ra = 
  182                     IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
  183                         M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  184                 if (ra == NULL) {
  185                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  186                             "structure\n");
  187                         return;
  188                 }
  189         } else
  190                 ra = ni->ni_rctls;
  191         ra->ra_rs = rsa;
  192         ra->ra_rates = *rs;
  193         rssadapt_updatestats(ra);
  194 
  195         /* pick initial rate */
  196         for (ra->ra_rix = rs->rs_nrates - 1;
  197              ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
  198              ra->ra_rix--)
  199                 ;
  200         ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
  201         ra->ra_ticks = ticks;
  202 
  203         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  204             "RSSADAPT initial rate %d", ni->ni_txrate);
  205 }
  206 
  207 static void
  208 rssadapt_node_deinit(struct ieee80211_node *ni)
  209 {
  210 
  211         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
  212 }
  213 
  214 static __inline int
  215 bucket(int pktlen)
  216 {
  217         int i, top, thridx;
  218 
  219         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  220              i < IEEE80211_RSSADAPT_BKTS;
  221              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  222                 thridx = i;
  223                 if (pktlen <= top)
  224                         break;
  225         }
  226         return thridx;
  227 }
  228 
  229 static int
  230 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
  231 {
  232         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  233         u_int pktlen = iarg;
  234         const struct ieee80211_rateset *rs = &ra->ra_rates;
  235         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  236         int rix, rssi;
  237 
  238         if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
  239                 rssadapt_updatestats(ra);
  240                 ra->ra_ticks = ticks;
  241         }
  242 
  243         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  244 
  245         /* XXX this is average rssi, should be using last value */
  246         rssi = ni->ni_ic->ic_node_getrssi(ni);
  247         for (rix = rs->rs_nrates-1; rix >= 0; rix--)
  248                 if ((*thrs)[rix] < (rssi << 8))
  249                         break;
  250         if (rix != ra->ra_rix) {
  251                 /* update public rate */
  252                 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
  253                 ra->ra_rix = rix;
  254 
  255                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  256                     "RSSADAPT new rate %d (pktlen %d rssi %d)",
  257                     ni->ni_txrate, pktlen, rssi);
  258         }
  259         return rix;
  260 }
  261 
  262 /*
  263  * Adapt the data rate to suit the conditions.  When a transmitted
  264  * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
  265  * raise the RSS threshold for transmitting packets of similar length at
  266  * the same data rate.
  267  */
  268 static void
  269 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  270 {
  271         uint16_t last_thr;
  272         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  273         u_int rix;
  274 
  275         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  276 
  277         rix = ra->ra_rix;
  278         last_thr = (*thrs)[rix];
  279         (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
  280             last_thr, (rssi << 8));
  281 
  282         IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  283             "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
  284             ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  285             last_thr, (*thrs)[rix], rssi);
  286 }
  287 
  288 static void
  289 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
  290 {
  291         uint16_t (*thrs)[IEEE80211_RATE_SIZE];
  292         uint16_t newthr, oldthr;
  293         int rix;
  294 
  295         thrs = &ra->ra_rate_thresh[bucket(pktlen)];
  296 
  297         rix = ra->ra_rix;
  298         if ((*thrs)[rix + 1] > (*thrs)[rix]) {
  299                 oldthr = (*thrs)[rix + 1];
  300                 if ((*thrs)[rix] == 0)
  301                         newthr = (rssi << 8);
  302                 else
  303                         newthr = (*thrs)[rix];
  304                 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
  305                     oldthr, newthr);
  306 
  307                 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
  308                     "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
  309                     ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
  310                     oldthr, newthr, rssi);
  311 
  312                 ra->ra_last_raise = ticks;
  313         }
  314 }
  315 
  316 static void
  317 rssadapt_tx_complete(const struct ieee80211_node *ni,
  318     const struct ieee80211_ratectl_tx_status *status)
  319 {
  320         struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
  321         int pktlen, rssi;
  322 
  323         if ((status->flags &
  324             (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI)) !=
  325             (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI))
  326                 return;
  327 
  328         pktlen = status->pktlen;
  329         rssi = status->rssi;
  330 
  331         if (status->status == IEEE80211_RATECTL_TX_SUCCESS) {
  332                 ra->ra_nok++;
  333                 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
  334                     (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
  335                         rssadapt_raise_rate(ra, pktlen, rssi);
  336         } else {
  337                 ra->ra_nfail++;
  338                 rssadapt_lower_rate(ra, pktlen, rssi);
  339         }
  340 }
  341 
  342 static int
  343 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
  344 {
  345         struct ieee80211vap *vap = arg1;
  346         struct ieee80211_rssadapt *rs = vap->iv_rs;
  347         int msecs = ticks_to_msecs(rs->interval);
  348         int error;
  349 
  350         error = sysctl_handle_int(oidp, &msecs, 0, req);
  351         if (error || !req->newptr)
  352                 return error;
  353         rssadapt_setinterval(vap, msecs);
  354         return 0;
  355 }
  356 
  357 static void
  358 rssadapt_sysctlattach(struct ieee80211vap *vap,
  359     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  360 {
  361 
  362         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  363             "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  364             0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
  365 }

Cache object: ec56b1a397cc533259a2e06a5923d619


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