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 /* $NetBSD: ieee80211_rssadapt.c,v 1.21 2016/09/27 20:20:06 christos Exp $ */
    2 /*-
    3  * Copyright (c) 2003, 2004 David Young.  All rights reserved.
    4  *
    5  * Redistribution and use in source and binary forms, with or
    6  * without modification, are permitted provided that the following
    7  * conditions are met:
    8  * 1. Redistributions of source code must retain the above copyright
    9  *    notice, this list of conditions and the following disclaimer.
   10  * 2. Redistributions in binary form must reproduce the above
   11  *    copyright notice, this list of conditions and the following
   12  *    disclaimer in the documentation and/or other materials provided
   13  *    with the distribution.
   14  *
   15  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
   16  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
   17  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
   18  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
   19  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   20  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
   21  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   22  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
   23  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
   24  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   25  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
   26  * OF SUCH DAMAGE.
   27  */
   28 
   29 #include <sys/cdefs.h>
   30 #ifdef __NetBSD__
   31 __KERNEL_RCSID(0, "$NetBSD: ieee80211_rssadapt.c,v 1.21 2016/09/27 20:20:06 christos Exp $");
   32 #endif
   33 
   34 #include <sys/param.h>
   35 #include <sys/types.h>
   36 #include <sys/kernel.h>         /* for hz */
   37 #include <sys/sysctl.h>
   38 
   39 #include <net/if.h>
   40 #include <net/if_media.h>
   41 #include <net/if_ether.h>
   42 
   43 #include <net80211/ieee80211_netbsd.h>
   44 #include <net80211/ieee80211_var.h>
   45 #include <net80211/ieee80211.h>
   46 #include <net80211/ieee80211_rssadapt.h>
   47 
   48 #ifdef interpolate
   49 #undef interpolate
   50 #endif
   51 #define interpolate(parm, old, new) ((parm##_old * (old) + \
   52                                      (parm##_denom - parm##_old) * (new)) / \
   53                                     parm##_denom)
   54 
   55 #ifdef IEEE80211_DEBUG
   56 static  struct timeval lastrateadapt;   /* time of last rate adaptation msg */
   57 static  int currssadaptps = 0;          /* rate-adaptation msgs this second */
   58 static  int ieee80211_adaptrate = 4;    /* rate-adaptation max msgs/sec */
   59 
   60 #define RSSADAPT_DO_PRINT() \
   61         ((ieee80211_rssadapt_debug > 0) && \
   62          ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate))
   63 #define RSSADAPT_PRINTF(X) \
   64         if (RSSADAPT_DO_PRINT()) \
   65                 printf X
   66 
   67 int ieee80211_rssadapt_debug = 0;
   68 
   69 #else
   70 #define RSSADAPT_DO_PRINT() (0)
   71 #define RSSADAPT_PRINTF(X)
   72 #endif
   73 
   74 static struct ieee80211_rssadapt_expavgctl master_expavgctl = {
   75         .rc_decay_denom = 16,
   76         .rc_decay_old = 15,
   77         .rc_thresh_denom = 8,
   78         .rc_thresh_old = 4,
   79         .rc_avgrssi_denom = 8,
   80         .rc_avgrssi_old = 4
   81 };
   82 
   83 #ifdef __NetBSD__
   84 #ifdef IEEE80211_DEBUG
   85 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
   86 static int
   87 sysctl_ieee80211_rssadapt_debug(SYSCTLFN_ARGS)
   88 {
   89         int error, t;
   90         struct sysctlnode node;
   91 
   92         node = *rnode;
   93         t = *(int*)rnode->sysctl_data;
   94         node.sysctl_data = &t;
   95         error = sysctl_lookup(SYSCTLFN_CALL(&node));
   96         if (error || newp == NULL)
   97                 return (error);
   98 
   99         if (t < 0 || t > 2)
  100                 return (EINVAL);
  101         *(int*)rnode->sysctl_data = t;
  102 
  103         return (0);
  104 }
  105 #endif /* IEEE80211_DEBUG */
  106 
  107 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
  108 static int
  109 sysctl_ieee80211_rssadapt_expavgctl(SYSCTLFN_ARGS)
  110 {
  111         struct ieee80211_rssadapt_expavgctl rc;
  112         int error;
  113         struct sysctlnode node;
  114 
  115         node = *rnode;
  116         rc = *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data;
  117         node.sysctl_data = &rc;
  118         error = sysctl_lookup(SYSCTLFN_CALL(&node));
  119         if (error || newp == NULL)
  120                 return (error);
  121 
  122         if (/* rc.rc_decay_old < 0 || */
  123             rc.rc_decay_denom < rc.rc_decay_old)
  124                 return (EINVAL);
  125 
  126         if (/* rc.rc_thresh_old < 0 || */
  127             rc.rc_thresh_denom < rc.rc_thresh_old)
  128                 return (EINVAL);
  129 
  130         if (/* rc.rc_avgrssi_old < 0 || */
  131             rc.rc_avgrssi_denom < rc.rc_avgrssi_old)
  132                 return (EINVAL);
  133 
  134         *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data = rc;
  135 
  136         return (0);
  137 }
  138 
  139 /*
  140  * Setup sysctl(3) MIB, net.ieee80211.*
  141  *
  142  * TBD condition CTLFLAG_PERMANENT on being a module or not
  143  */
  144 void
  145 ieee80211_rssadapt_sysctl_setup(struct sysctllog **clog)
  146 {
  147         int rc;
  148         const struct sysctlnode *node;
  149 
  150         if ((rc = sysctl_createv(clog, 0, NULL, &node,
  151             CTLFLAG_PERMANENT, CTLTYPE_NODE, "link", NULL,
  152             NULL, 0, NULL, 0, CTL_NET, PF_LINK, CTL_EOL)) != 0)
  153                 goto err;
  154 
  155         if ((rc = sysctl_createv(clog, 0, &node, &node,
  156             CTLFLAG_PERMANENT, CTLTYPE_NODE, "ieee80211", NULL,
  157             NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
  158                 goto err;
  159 
  160         if ((rc = sysctl_createv(clog, 0, &node, &node,
  161             CTLFLAG_PERMANENT, CTLTYPE_NODE, "rssadapt",
  162             SYSCTL_DESCR("Received Signal Strength adaptation controls"),
  163             NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
  164                 goto err;
  165 
  166 #ifdef IEEE80211_DEBUG
  167         /* control debugging printfs */
  168         if ((rc = sysctl_createv(clog, 0, &node, NULL,
  169             CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "debug",
  170             SYSCTL_DESCR("Enable RSS adaptation debugging output"),
  171             sysctl_ieee80211_rssadapt_debug, 0, &ieee80211_rssadapt_debug, 0,
  172             CTL_CREATE, CTL_EOL)) != 0)
  173                 goto err;
  174 #endif /* IEEE80211_DEBUG */
  175 
  176         /* control rate of decay for exponential averages */
  177         if ((rc = sysctl_createv(clog, 0, &node, NULL,
  178             CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_STRUCT,
  179             "expavgctl", SYSCTL_DESCR("RSS exponential averaging control"),
  180             sysctl_ieee80211_rssadapt_expavgctl, 0,
  181             &master_expavgctl, sizeof(master_expavgctl), CTL_CREATE,
  182             CTL_EOL)) != 0)
  183                 goto err;
  184 
  185         return;
  186 err:
  187         printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
  188 }
  189 #endif /* __NetBSD__ */
  190 
  191 int
  192 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra,
  193     struct ieee80211_rateset *rs, struct ieee80211_frame *wh, u_int len,
  194     int fixed_rate, const char *dvname, int do_not_adapt)
  195 {
  196         u_int16_t (*thrs)[IEEE80211_RATE_SIZE];
  197         int flags = 0, i, rateidx = 0, thridx, top;
  198 
  199         if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
  200                 flags |= IEEE80211_RATE_BASIC;
  201 
  202         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  203              i < IEEE80211_RSSADAPT_BKTS;
  204              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  205                 thridx = i;
  206                 if (len <= top)
  207                         break;
  208         }
  209 
  210         thrs = &ra->ra_rate_thresh[thridx];
  211 
  212         if (fixed_rate != -1) {
  213                 if ((rs->rs_rates[fixed_rate] & flags) == flags) {
  214                         rateidx = fixed_rate;
  215                         goto out;
  216                 }
  217                 flags |= IEEE80211_RATE_BASIC;
  218                 i = fixed_rate;
  219         } else
  220                 i = rs->rs_nrates;
  221 
  222         while (--i >= 0) {
  223                 rateidx = i;
  224                 if ((rs->rs_rates[i] & flags) != flags)
  225                         continue;
  226                 if (do_not_adapt)
  227                         break;
  228                 if ((*thrs)[i] < ra->ra_avg_rssi)
  229                         break;
  230         }
  231 
  232 out:
  233 #ifdef IEEE80211_DEBUG
  234         if (ieee80211_rssadapt_debug && dvname != NULL) {
  235                 printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n",
  236                     dvname, ether_sprintf(wh->i_addr1), len,
  237                     (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2,
  238                     (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
  239                     (*thrs)[rateidx], ra->ra_avg_rssi);
  240         }
  241 #endif /* IEEE80211_DEBUG */
  242         return rateidx;
  243 }
  244 
  245 void
  246 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra)
  247 {
  248         long interval;
  249 
  250         ra->ra_pktrate =
  251             (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
  252         ra->ra_nfail = ra->ra_nok = 0;
  253 
  254         /* a node is eligible for its rate to be raised every 1/10 to 10
  255          * seconds, more eligible in proportion to recent packet rates.
  256          */
  257         interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
  258         ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
  259         ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
  260 }
  261 
  262 void
  263 ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
  264     struct ieee80211_rssadapt *ra, int rssi)
  265 {
  266 #ifdef IEEE80211_DEBUG
  267         int last_avg_rssi = ra->ra_avg_rssi;
  268 #endif
  269 
  270         ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi,
  271                                       ra->ra_avg_rssi, (rssi << 8));
  272 
  273         RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n",
  274             ic->ic_ifp->if_xname, ether_sprintf(ni->ni_macaddr),
  275             rssi, last_avg_rssi, ra->ra_avg_rssi));
  276 }
  277 
  278 /*
  279  * Adapt the data rate to suit the conditions.  When a transmitted
  280  * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions,
  281  * raise the RSS threshold for transmitting packets of similar length at
  282  * the same data rate.
  283  */
  284 void
  285 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic,
  286     struct ieee80211_node *ni, struct ieee80211_rssadapt *ra,
  287     struct ieee80211_rssdesc *id)
  288 {
  289         struct ieee80211_rateset *rs = &ni->ni_rates;
  290         u_int16_t last_thr;
  291         u_int i, thridx, top;
  292 
  293         ra->ra_nfail++;
  294 
  295         if (id->id_rateidx >= rs->rs_nrates) {
  296                 RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: "
  297                     "%s rate #%d > #%d out of bounds\n",
  298                     ether_sprintf(ni->ni_macaddr), id->id_rateidx,
  299                         rs->rs_nrates - 1));
  300                 return;
  301         }
  302 
  303         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  304              i < IEEE80211_RSSADAPT_BKTS;
  305              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  306                 thridx = i;
  307                 if (id->id_len <= top)
  308                         break;
  309         }
  310 
  311         last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
  312         ra->ra_rate_thresh[thridx][id->id_rateidx] =
  313             interpolate(master_expavgctl.rc_thresh, last_thr,
  314                         (id->id_rssi << 8));
  315 
  316         RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n",
  317             ic->ic_ifp->if_xname, ether_sprintf(ni->ni_macaddr),
  318             id->id_rssi, id->id_len,
  319             (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2,
  320             (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
  321             last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx]));
  322 }
  323 
  324 void
  325 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic,
  326     struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id)
  327 {
  328         u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
  329         struct ieee80211_node *ni = id->id_node;
  330         struct ieee80211_rateset *rs = &ni->ni_rates;
  331         int i, rate, top;
  332 #ifdef IEEE80211_DEBUG
  333         int j;
  334 #endif
  335 
  336         ra->ra_nok++;
  337 
  338         if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
  339                 return;
  340 
  341         for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
  342              i < IEEE80211_RSSADAPT_BKTS;
  343              i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
  344                 thrs = &ra->ra_rate_thresh[i];
  345                 if (id->id_len <= top)
  346                         break;
  347         }
  348 
  349         if (id->id_rateidx + 1 < rs->rs_nrates &&
  350             (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
  351                 rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
  352 
  353                 __USE(rate);
  354                 RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ",
  355                     ic->ic_ifp->if_xname,
  356                     IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i),
  357                     rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1]));
  358                 oldthr = (*thrs)[id->id_rateidx + 1];
  359                 if ((*thrs)[id->id_rateidx] == 0)
  360                         newthr = ra->ra_avg_rssi;
  361                 else
  362                         newthr = (*thrs)[id->id_rateidx];
  363                 (*thrs)[id->id_rateidx + 1] =
  364                     interpolate(master_expavgctl.rc_decay, oldthr, newthr);
  365 
  366                 RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1]));
  367         }
  368 
  369 #ifdef IEEE80211_DEBUG
  370         if (RSSADAPT_DO_PRINT()) {
  371                 printf("%s: dst %s thresholds\n", ic->ic_ifp->if_xname,
  372                     ether_sprintf(ni->ni_macaddr));
  373                 for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) {
  374                         printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER * i));
  375                         for (j = 0; j < rs->rs_nrates; j++) {
  376                                 rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL);
  377                                 printf(", T[%d.%d] = %d", rate / 2,
  378                                     rate * 5 % 10, ra->ra_rate_thresh[i][j]);
  379                         }
  380                         printf("\n");
  381                 }
  382         }
  383 #endif /* IEEE80211_DEBUG */
  384 }

Cache object: 81c17de7c1447a8162ba87fde658960a


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