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_amrr.c

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    1 /*      $OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $       */
    2 
    3 /*-
    4  * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
    5  * Copyright (c) 2006
    6  *      Damien Bergamini <damien.bergamini@free.fr>
    7  *
    8  * Permission to use, copy, modify, and distribute this software for any
    9  * purpose with or without fee is hereby granted, provided that the above
   10  * copyright notice and this permission notice appear in all copies.
   11  *
   12  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
   13  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
   14  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
   15  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
   16  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
   17  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
   18  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
   19  */
   20 
   21 #include <sys/cdefs.h>
   22 __FBSDID("$FreeBSD: releng/10.1/sys/net80211/ieee80211_amrr.c 252736 2013-07-05 00:03:53Z adrian $");
   23 
   24 /*-
   25  * Naive implementation of the Adaptive Multi Rate Retry algorithm:
   26  *
   27  * "IEEE 802.11 Rate Adaptation: A Practical Approach"
   28  *  Mathieu Lacage, Hossein Manshaei, Thierry Turletti
   29  *  INRIA Sophia - Projet Planete
   30  *  http://www-sop.inria.fr/rapports/sophia/RR-5208.html
   31  */
   32 #include "opt_wlan.h"
   33 
   34 #include <sys/param.h>
   35 #include <sys/kernel.h>
   36 #include <sys/module.h>
   37 #include <sys/socket.h>
   38 #include <sys/sysctl.h>
   39 
   40 #include <net/if.h>
   41 #include <net/if_media.h>
   42 
   43 #ifdef INET
   44 #include <netinet/in.h>
   45 #include <netinet/if_ether.h>
   46 #endif
   47 
   48 #include <net80211/ieee80211_var.h>
   49 #include <net80211/ieee80211_ht.h>
   50 #include <net80211/ieee80211_amrr.h>
   51 #include <net80211/ieee80211_ratectl.h>
   52 
   53 #define is_success(amn) \
   54         ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
   55 #define is_failure(amn) \
   56         ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
   57 #define is_enough(amn)          \
   58         ((amn)->amn_txcnt > 10)
   59 
   60 static void     amrr_setinterval(const struct ieee80211vap *, int);
   61 static void     amrr_init(struct ieee80211vap *);
   62 static void     amrr_deinit(struct ieee80211vap *);
   63 static void     amrr_node_init(struct ieee80211_node *);
   64 static void     amrr_node_deinit(struct ieee80211_node *);
   65 static int      amrr_update(struct ieee80211_amrr *,
   66                         struct ieee80211_amrr_node *, struct ieee80211_node *);
   67 static int      amrr_rate(struct ieee80211_node *, void *, uint32_t);
   68 static void     amrr_tx_complete(const struct ieee80211vap *,
   69                         const struct ieee80211_node *, int, 
   70                         void *, void *);
   71 static void     amrr_tx_update(const struct ieee80211vap *vap,
   72                         const struct ieee80211_node *, void *, void *, void *);
   73 static void     amrr_sysctlattach(struct ieee80211vap *,
   74                         struct sysctl_ctx_list *, struct sysctl_oid *);
   75 
   76 /* number of references from net80211 layer */
   77 static  int nrefs = 0;
   78 
   79 static const struct ieee80211_ratectl amrr = {
   80         .ir_name        = "amrr",
   81         .ir_attach      = NULL,
   82         .ir_detach      = NULL,
   83         .ir_init        = amrr_init,
   84         .ir_deinit      = amrr_deinit,
   85         .ir_node_init   = amrr_node_init,
   86         .ir_node_deinit = amrr_node_deinit,
   87         .ir_rate        = amrr_rate,
   88         .ir_tx_complete = amrr_tx_complete,
   89         .ir_tx_update   = amrr_tx_update,
   90         .ir_setinterval = amrr_setinterval,
   91 };
   92 IEEE80211_RATECTL_MODULE(amrr, 1);
   93 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
   94 
   95 static void
   96 amrr_setinterval(const struct ieee80211vap *vap, int msecs)
   97 {
   98         struct ieee80211_amrr *amrr = vap->iv_rs;
   99         int t;
  100 
  101         if (msecs < 100)
  102                 msecs = 100;
  103         t = msecs_to_ticks(msecs);
  104         amrr->amrr_interval = (t < 1) ? 1 : t;
  105 }
  106 
  107 static void
  108 amrr_init(struct ieee80211vap *vap)
  109 {
  110         struct ieee80211_amrr *amrr;
  111 
  112         KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
  113 
  114         amrr = vap->iv_rs = malloc(sizeof(struct ieee80211_amrr),
  115             M_80211_RATECTL, M_NOWAIT|M_ZERO);
  116         if (amrr == NULL) {
  117                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  118                 return;
  119         }
  120         amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
  121         amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
  122         amrr_setinterval(vap, 500 /* ms */);
  123         amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  124 }
  125 
  126 static void
  127 amrr_deinit(struct ieee80211vap *vap)
  128 {
  129         free(vap->iv_rs, M_80211_RATECTL);
  130 }
  131 
  132 static int
  133 amrr_node_is_11n(struct ieee80211_node *ni)
  134 {
  135 
  136         if (ni->ni_chan == NULL)
  137                 return (0);
  138         if (ni->ni_chan == IEEE80211_CHAN_ANYC)
  139                 return (0);
  140         return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
  141 }
  142 
  143 static void
  144 amrr_node_init(struct ieee80211_node *ni)
  145 {
  146         const struct ieee80211_rateset *rs = NULL;
  147         struct ieee80211vap *vap = ni->ni_vap;
  148         struct ieee80211_amrr *amrr = vap->iv_rs;
  149         struct ieee80211_amrr_node *amn;
  150         uint8_t rate;
  151 
  152         if (ni->ni_rctls == NULL) {
  153                 ni->ni_rctls = amn = malloc(sizeof(struct ieee80211_amrr_node),
  154                     M_80211_RATECTL, M_NOWAIT|M_ZERO);
  155                 if (amn == NULL) {
  156                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  157                             "structure\n");
  158                         return;
  159                 }
  160         } else
  161                 amn = ni->ni_rctls;
  162         amn->amn_amrr = amrr;
  163         amn->amn_success = 0;
  164         amn->amn_recovery = 0;
  165         amn->amn_txcnt = amn->amn_retrycnt = 0;
  166         amn->amn_success_threshold = amrr->amrr_min_success_threshold;
  167 
  168         /* 11n or not? Pick the right rateset */
  169         if (amrr_node_is_11n(ni)) {
  170                 /* XXX ew */
  171                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  172                     "%s: 11n node", __func__);
  173                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  174         } else {
  175                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  176                     "%s: non-11n node", __func__);
  177                 rs = &ni->ni_rates;
  178         }
  179 
  180         /* Initial rate - lowest */
  181         rate = rs->rs_rates[0];
  182 
  183         /* XXX clear the basic rate flag if it's not 11n */
  184         if (! amrr_node_is_11n(ni))
  185                 rate &= IEEE80211_RATE_VAL;
  186 
  187         /* pick initial rate from the rateset - HT or otherwise */
  188         for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
  189             amn->amn_rix--) {
  190                 /* legacy - anything < 36mbit, stop searching */
  191                 /* 11n - stop at MCS4 / MCS12 / MCS28 */
  192                 if (amrr_node_is_11n(ni) &&
  193                     (rs->rs_rates[amn->amn_rix] & 0x7) < 4)
  194                         break;
  195                 else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
  196                         break;
  197                 rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  198         }
  199 
  200         /* if the rate is an 11n rate, ensure the MCS bit is set */
  201         if (amrr_node_is_11n(ni))
  202                 rate |= IEEE80211_RATE_MCS;
  203 
  204         /* Assign initial rate from the rateset */
  205         ni->ni_txrate = rate;
  206         amn->amn_ticks = ticks;
  207 
  208         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  209             "AMRR: nrates=%d, initial rate %d",
  210             rs->rs_nrates,
  211             rate);
  212 }
  213 
  214 static void
  215 amrr_node_deinit(struct ieee80211_node *ni)
  216 {
  217         free(ni->ni_rctls, M_80211_RATECTL);
  218 }
  219 
  220 static int
  221 amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
  222     struct ieee80211_node *ni)
  223 {
  224         int rix = amn->amn_rix;
  225         const struct ieee80211_rateset *rs = NULL;
  226 
  227         KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
  228 
  229         /* 11n or not? Pick the right rateset */
  230         if (amrr_node_is_11n(ni)) {
  231                 /* XXX ew */
  232                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  233         } else {
  234                 rs = &ni->ni_rates;
  235         }
  236 
  237         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  238             "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
  239             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  240             amn->amn_txcnt,
  241             amn->amn_retrycnt);
  242 
  243         /*
  244          * XXX This is totally bogus for 11n, as although high MCS
  245          * rates for each stream may be failing, the next stream
  246          * should be checked.
  247          *
  248          * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
  249          * MCS23, we should skip 6/7 and try 8 onwards.
  250          */
  251         if (is_success(amn)) {
  252                 amn->amn_success++;
  253                 if (amn->amn_success >= amn->amn_success_threshold &&
  254                     rix + 1 < rs->rs_nrates) {
  255                         amn->amn_recovery = 1;
  256                         amn->amn_success = 0;
  257                         rix++;
  258                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  259                             "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
  260                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  261                             amn->amn_txcnt, amn->amn_retrycnt);
  262                 } else {
  263                         amn->amn_recovery = 0;
  264                 }
  265         } else if (is_failure(amn)) {
  266                 amn->amn_success = 0;
  267                 if (rix > 0) {
  268                         if (amn->amn_recovery) {
  269                                 amn->amn_success_threshold *= 2;
  270                                 if (amn->amn_success_threshold >
  271                                     amrr->amrr_max_success_threshold)
  272                                         amn->amn_success_threshold =
  273                                             amrr->amrr_max_success_threshold;
  274                         } else {
  275                                 amn->amn_success_threshold =
  276                                     amrr->amrr_min_success_threshold;
  277                         }
  278                         rix--;
  279                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  280                             "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
  281                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  282                             amn->amn_txcnt, amn->amn_retrycnt);
  283                 }
  284                 amn->amn_recovery = 0;
  285         }
  286 
  287         /* reset counters */
  288         amn->amn_txcnt = 0;
  289         amn->amn_retrycnt = 0;
  290 
  291         return rix;
  292 }
  293 
  294 /*
  295  * Return the rate index to use in sending a data frame.
  296  * Update our internal state if it's been long enough.
  297  * If the rate changes we also update ni_txrate to match.
  298  */
  299 static int
  300 amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
  301 {
  302         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  303         struct ieee80211_amrr *amrr = amn->amn_amrr;
  304         const struct ieee80211_rateset *rs = NULL;
  305         int rix;
  306 
  307         /* 11n or not? Pick the right rateset */
  308         if (amrr_node_is_11n(ni)) {
  309                 /* XXX ew */
  310                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  311         } else {
  312                 rs = &ni->ni_rates;
  313         }
  314 
  315         if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
  316                 rix = amrr_update(amrr, amn, ni);
  317                 if (rix != amn->amn_rix) {
  318                         /* update public rate */
  319                         ni->ni_txrate = rs->rs_rates[rix];
  320                         /* XXX strip basic rate flag from txrate, if non-11n */
  321                         if (amrr_node_is_11n(ni))
  322                                 ni->ni_txrate |= IEEE80211_RATE_MCS;
  323                         else
  324                                 ni->ni_txrate &= IEEE80211_RATE_VAL;
  325                         amn->amn_rix = rix;
  326                 }
  327                 amn->amn_ticks = ticks;
  328         } else
  329                 rix = amn->amn_rix;
  330         return rix;
  331 }
  332 
  333 /*
  334  * Update statistics with tx complete status.  Ok is non-zero
  335  * if the packet is known to be ACK'd.  Retries has the number
  336  * retransmissions (i.e. xmit attempts - 1).
  337  */
  338 static void
  339 amrr_tx_complete(const struct ieee80211vap *vap,
  340     const struct ieee80211_node *ni, int ok,
  341     void *arg1, void *arg2 __unused)
  342 {
  343         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  344         int retries = *(int *)arg1;
  345 
  346         amn->amn_txcnt++;
  347         if (ok)
  348                 amn->amn_success++;
  349         amn->amn_retrycnt += retries;
  350 }
  351 
  352 /*
  353  * Set tx count/retry statistics explicitly.  Intended for
  354  * drivers that poll the device for statistics maintained
  355  * in the device.
  356  */
  357 static void
  358 amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
  359     void *arg1, void *arg2, void *arg3)
  360 {
  361         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  362         int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
  363 
  364         amn->amn_txcnt = txcnt;
  365         amn->amn_success = success;
  366         amn->amn_retrycnt = retrycnt;
  367 }
  368 
  369 static int
  370 amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
  371 {
  372         struct ieee80211vap *vap = arg1;
  373         struct ieee80211_amrr *amrr = vap->iv_rs;
  374         int msecs = ticks_to_msecs(amrr->amrr_interval);
  375         int error;
  376 
  377         error = sysctl_handle_int(oidp, &msecs, 0, req);
  378         if (error || !req->newptr)
  379                 return error;
  380         amrr_setinterval(vap, msecs);
  381         return 0;
  382 }
  383 
  384 static void
  385 amrr_sysctlattach(struct ieee80211vap *vap,
  386     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  387 {
  388         struct ieee80211_amrr *amrr = vap->iv_rs;
  389 
  390         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  391             "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  392             0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
  393         /* XXX bounds check values */
  394         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  395             "amrr_max_sucess_threshold", CTLFLAG_RW,
  396             &amrr->amrr_max_success_threshold, 0, "");
  397         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  398             "amrr_min_sucess_threshold", CTLFLAG_RW,
  399             &amrr->amrr_min_success_threshold, 0, "");
  400 }

Cache object: 36b75aa3143ec90f3e32ead1c8d05ff0


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