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/12.0/sys/net80211/ieee80211_amrr.c 321401 2017-07-23 22:38:00Z avos $");
   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/malloc.h>
   37 #include <sys/module.h>
   38 #include <sys/sbuf.h>
   39 #include <sys/socket.h>
   40 #include <sys/sysctl.h>
   41 
   42 #include <net/if.h>
   43 #include <net/if_var.h>
   44 #include <net/if_media.h>
   45 #include <net/ethernet.h>
   46 
   47 #ifdef INET
   48 #include <netinet/in.h>
   49 #include <netinet/if_ether.h>
   50 #endif
   51 
   52 #include <net80211/ieee80211_var.h>
   53 #include <net80211/ieee80211_ht.h>
   54 #include <net80211/ieee80211_amrr.h>
   55 #include <net80211/ieee80211_ratectl.h>
   56 
   57 #define is_success(amn) \
   58         ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
   59 #define is_failure(amn) \
   60         ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
   61 #define is_enough(amn)          \
   62         ((amn)->amn_txcnt > 10)
   63 
   64 static void     amrr_setinterval(const struct ieee80211vap *, int);
   65 static void     amrr_init(struct ieee80211vap *);
   66 static void     amrr_deinit(struct ieee80211vap *);
   67 static void     amrr_node_init(struct ieee80211_node *);
   68 static void     amrr_node_deinit(struct ieee80211_node *);
   69 static int      amrr_update(struct ieee80211_amrr *,
   70                         struct ieee80211_amrr_node *, struct ieee80211_node *);
   71 static int      amrr_rate(struct ieee80211_node *, void *, uint32_t);
   72 static void     amrr_tx_complete(const struct ieee80211_node *,
   73                         const struct ieee80211_ratectl_tx_status *);
   74 static void     amrr_tx_update_cb(void *, struct ieee80211_node *);
   75 static void     amrr_tx_update(struct ieee80211vap *vap,
   76                         struct ieee80211_ratectl_tx_stats *);
   77 static void     amrr_sysctlattach(struct ieee80211vap *,
   78                         struct sysctl_ctx_list *, struct sysctl_oid *);
   79 static void     amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s);
   80 
   81 /* number of references from net80211 layer */
   82 static  int nrefs = 0;
   83 
   84 static const struct ieee80211_ratectl amrr = {
   85         .ir_name        = "amrr",
   86         .ir_attach      = NULL,
   87         .ir_detach      = NULL,
   88         .ir_init        = amrr_init,
   89         .ir_deinit      = amrr_deinit,
   90         .ir_node_init   = amrr_node_init,
   91         .ir_node_deinit = amrr_node_deinit,
   92         .ir_rate        = amrr_rate,
   93         .ir_tx_complete = amrr_tx_complete,
   94         .ir_tx_update   = amrr_tx_update,
   95         .ir_setinterval = amrr_setinterval,
   96         .ir_node_stats  = amrr_node_stats,
   97 };
   98 IEEE80211_RATECTL_MODULE(amrr, 1);
   99 IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
  100 
  101 static void
  102 amrr_setinterval(const struct ieee80211vap *vap, int msecs)
  103 {
  104         struct ieee80211_amrr *amrr = vap->iv_rs;
  105         int t;
  106 
  107         if (msecs < 100)
  108                 msecs = 100;
  109         t = msecs_to_ticks(msecs);
  110         amrr->amrr_interval = (t < 1) ? 1 : t;
  111 }
  112 
  113 static void
  114 amrr_init(struct ieee80211vap *vap)
  115 {
  116         struct ieee80211_amrr *amrr;
  117 
  118         KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
  119 
  120         nrefs++;                /* XXX locking */
  121         amrr = vap->iv_rs = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr),
  122             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  123         if (amrr == NULL) {
  124                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  125                 return;
  126         }
  127         amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
  128         amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
  129         amrr_setinterval(vap, 500 /* ms */);
  130         amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  131 }
  132 
  133 static void
  134 amrr_deinit(struct ieee80211vap *vap)
  135 {
  136         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
  137         KASSERT(nrefs > 0, ("imbalanced attach/detach"));
  138         nrefs--;                /* XXX locking */
  139 }
  140 
  141 /*
  142  * Return whether 11n rates are possible.
  143  *
  144  * Some 11n devices may return HT information but no HT rates.
  145  * Thus, we shouldn't treat them as an 11n node.
  146  */
  147 static int
  148 amrr_node_is_11n(struct ieee80211_node *ni)
  149 {
  150 
  151         if (ni->ni_chan == NULL)
  152                 return (0);
  153         if (ni->ni_chan == IEEE80211_CHAN_ANYC)
  154                 return (0);
  155         if (IEEE80211_IS_CHAN_HT(ni->ni_chan) && ni->ni_htrates.rs_nrates == 0)
  156                 return (0);
  157         return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
  158 }
  159 
  160 static void
  161 amrr_node_init(struct ieee80211_node *ni)
  162 {
  163         const struct ieee80211_rateset *rs = NULL;
  164         struct ieee80211vap *vap = ni->ni_vap;
  165         struct ieee80211_amrr *amrr = vap->iv_rs;
  166         struct ieee80211_amrr_node *amn;
  167         uint8_t rate;
  168 
  169         if (ni->ni_rctls == NULL) {
  170                 ni->ni_rctls = amn = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr_node),
  171                     M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  172                 if (amn == NULL) {
  173                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  174                             "structure\n");
  175                         return;
  176                 }
  177         } else
  178                 amn = ni->ni_rctls;
  179         amn->amn_amrr = amrr;
  180         amn->amn_success = 0;
  181         amn->amn_recovery = 0;
  182         amn->amn_txcnt = amn->amn_retrycnt = 0;
  183         amn->amn_success_threshold = amrr->amrr_min_success_threshold;
  184 
  185         /* 11n or not? Pick the right rateset */
  186         if (amrr_node_is_11n(ni)) {
  187                 /* XXX ew */
  188                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  189                     "%s: 11n node", __func__);
  190                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  191         } else {
  192                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  193                     "%s: non-11n node", __func__);
  194                 rs = &ni->ni_rates;
  195         }
  196 
  197         /* Initial rate - lowest */
  198         rate = rs->rs_rates[0];
  199 
  200         /* XXX clear the basic rate flag if it's not 11n */
  201         if (! amrr_node_is_11n(ni))
  202                 rate &= IEEE80211_RATE_VAL;
  203 
  204         /* pick initial rate from the rateset - HT or otherwise */
  205         /* Pick something low that's likely to succeed */
  206         for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
  207             amn->amn_rix--) {
  208                 /* legacy - anything < 36mbit, stop searching */
  209                 /* 11n - stop at MCS4 */
  210                 if (amrr_node_is_11n(ni)) {
  211                         if ((rs->rs_rates[amn->amn_rix] & 0x1f) < 4)
  212                                 break;
  213                 } else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
  214                         break;
  215         }
  216         rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  217 
  218         /* if the rate is an 11n rate, ensure the MCS bit is set */
  219         if (amrr_node_is_11n(ni))
  220                 rate |= IEEE80211_RATE_MCS;
  221 
  222         /* Assign initial rate from the rateset */
  223         ni->ni_txrate = rate;
  224         amn->amn_ticks = ticks;
  225 
  226         /* XXX TODO: we really need a rate-to-string method */
  227         /* XXX TODO: non-11n rate should be divided by two.. */
  228         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  229             "AMRR: nrates=%d, initial rate %s%d",
  230             rs->rs_nrates,
  231             amrr_node_is_11n(ni) ? "MCS " : "",
  232             rate & IEEE80211_RATE_VAL);
  233 }
  234 
  235 static void
  236 amrr_node_deinit(struct ieee80211_node *ni)
  237 {
  238         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
  239 }
  240 
  241 static int
  242 amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
  243     struct ieee80211_node *ni)
  244 {
  245         int rix = amn->amn_rix;
  246         const struct ieee80211_rateset *rs = NULL;
  247 
  248         KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
  249 
  250         /* 11n or not? Pick the right rateset */
  251         if (amrr_node_is_11n(ni)) {
  252                 /* XXX ew */
  253                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  254         } else {
  255                 rs = &ni->ni_rates;
  256         }
  257 
  258         /* XXX TODO: we really need a rate-to-string method */
  259         /* XXX TODO: non-11n rate should be divided by two.. */
  260         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  261             "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
  262             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  263             amn->amn_txcnt,
  264             amn->amn_retrycnt);
  265 
  266         /*
  267          * XXX This is totally bogus for 11n, as although high MCS
  268          * rates for each stream may be failing, the next stream
  269          * should be checked.
  270          *
  271          * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
  272          * MCS23, we should skip 6/7 and try 8 onwards.
  273          */
  274         if (is_success(amn)) {
  275                 amn->amn_success++;
  276                 if (amn->amn_success >= amn->amn_success_threshold &&
  277                     rix + 1 < rs->rs_nrates) {
  278                         amn->amn_recovery = 1;
  279                         amn->amn_success = 0;
  280                         rix++;
  281                         /* XXX TODO: we really need a rate-to-string method */
  282                         /* XXX TODO: non-11n rate should be divided by two.. */
  283                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  284                             "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
  285                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  286                             amn->amn_txcnt, amn->amn_retrycnt);
  287                 } else {
  288                         amn->amn_recovery = 0;
  289                 }
  290         } else if (is_failure(amn)) {
  291                 amn->amn_success = 0;
  292                 if (rix > 0) {
  293                         if (amn->amn_recovery) {
  294                                 amn->amn_success_threshold *= 2;
  295                                 if (amn->amn_success_threshold >
  296                                     amrr->amrr_max_success_threshold)
  297                                         amn->amn_success_threshold =
  298                                             amrr->amrr_max_success_threshold;
  299                         } else {
  300                                 amn->amn_success_threshold =
  301                                     amrr->amrr_min_success_threshold;
  302                         }
  303                         rix--;
  304                         /* XXX TODO: we really need a rate-to-string method */
  305                         /* XXX TODO: non-11n rate should be divided by two.. */
  306                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  307                             "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
  308                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  309                             amn->amn_txcnt, amn->amn_retrycnt);
  310                 }
  311                 amn->amn_recovery = 0;
  312         }
  313 
  314         /* reset counters */
  315         amn->amn_txcnt = 0;
  316         amn->amn_retrycnt = 0;
  317 
  318         return rix;
  319 }
  320 
  321 /*
  322  * Return the rate index to use in sending a data frame.
  323  * Update our internal state if it's been long enough.
  324  * If the rate changes we also update ni_txrate to match.
  325  */
  326 static int
  327 amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
  328 {
  329         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  330         struct ieee80211_amrr *amrr = amn->amn_amrr;
  331         const struct ieee80211_rateset *rs = NULL;
  332         int rix;
  333 
  334         /* 11n or not? Pick the right rateset */
  335         if (amrr_node_is_11n(ni)) {
  336                 /* XXX ew */
  337                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  338         } else {
  339                 rs = &ni->ni_rates;
  340         }
  341 
  342         if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
  343                 rix = amrr_update(amrr, amn, ni);
  344                 if (rix != amn->amn_rix) {
  345                         /* update public rate */
  346                         ni->ni_txrate = rs->rs_rates[rix];
  347                         /* XXX strip basic rate flag from txrate, if non-11n */
  348                         if (amrr_node_is_11n(ni))
  349                                 ni->ni_txrate |= IEEE80211_RATE_MCS;
  350                         else
  351                                 ni->ni_txrate &= IEEE80211_RATE_VAL;
  352                         amn->amn_rix = rix;
  353                 }
  354                 amn->amn_ticks = ticks;
  355         } else
  356                 rix = amn->amn_rix;
  357         return rix;
  358 }
  359 
  360 /*
  361  * Update statistics with tx complete status.  Ok is non-zero
  362  * if the packet is known to be ACK'd.  Retries has the number
  363  * retransmissions (i.e. xmit attempts - 1).
  364  */
  365 static void
  366 amrr_tx_complete(const struct ieee80211_node *ni,
  367     const struct ieee80211_ratectl_tx_status *status)
  368 {
  369         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  370         int retries;
  371 
  372         retries = 0;
  373         if (status->flags & IEEE80211_RATECTL_STATUS_LONG_RETRY)
  374                 retries = status->long_retries;
  375 
  376         amn->amn_txcnt++;
  377         if (status->status == IEEE80211_RATECTL_TX_SUCCESS)
  378                 amn->amn_success++;
  379         amn->amn_retrycnt += retries;
  380 }
  381 
  382 static void
  383 amrr_tx_update_cb(void *arg, struct ieee80211_node *ni)
  384 {
  385         struct ieee80211_ratectl_tx_stats *stats = arg;
  386         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  387         int txcnt, success, retrycnt;
  388 
  389         txcnt = stats->nframes;
  390         success = stats->nsuccess;
  391         retrycnt = 0;
  392         if (stats->flags & IEEE80211_RATECTL_TX_STATS_RETRIES)
  393                 retrycnt = stats->nretries;
  394 
  395         amn->amn_txcnt += txcnt;
  396         amn->amn_success += success;
  397         amn->amn_retrycnt += retrycnt;
  398 }
  399 
  400 /*
  401  * Set tx count/retry statistics explicitly.  Intended for
  402  * drivers that poll the device for statistics maintained
  403  * in the device.
  404  */
  405 static void
  406 amrr_tx_update(struct ieee80211vap *vap,
  407     struct ieee80211_ratectl_tx_stats *stats)
  408 {
  409 
  410         if (stats->flags & IEEE80211_RATECTL_TX_STATS_NODE)
  411                 amrr_tx_update_cb(stats, stats->ni);
  412         else {
  413                 ieee80211_iterate_nodes_vap(&vap->iv_ic->ic_sta, vap,
  414                     amrr_tx_update_cb, stats);
  415         }
  416 }
  417 
  418 static int
  419 amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
  420 {
  421         struct ieee80211vap *vap = arg1;
  422         struct ieee80211_amrr *amrr = vap->iv_rs;
  423         int msecs = ticks_to_msecs(amrr->amrr_interval);
  424         int error;
  425 
  426         error = sysctl_handle_int(oidp, &msecs, 0, req);
  427         if (error || !req->newptr)
  428                 return error;
  429         amrr_setinterval(vap, msecs);
  430         return 0;
  431 }
  432 
  433 static void
  434 amrr_sysctlattach(struct ieee80211vap *vap,
  435     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  436 {
  437         struct ieee80211_amrr *amrr = vap->iv_rs;
  438 
  439         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  440             "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  441             0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
  442         /* XXX bounds check values */
  443         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  444             "amrr_max_sucess_threshold", CTLFLAG_RW,
  445             &amrr->amrr_max_success_threshold, 0, "");
  446         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  447             "amrr_min_sucess_threshold", CTLFLAG_RW,
  448             &amrr->amrr_min_success_threshold, 0, "");
  449 }
  450 
  451 static void
  452 amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
  453 {
  454         int rate;
  455         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  456         struct ieee80211_rateset *rs;
  457 
  458         /* XXX TODO: check locking? */
  459 
  460         /* XXX TODO: this should be a method */
  461         if (amrr_node_is_11n(ni)) {
  462                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  463                 rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  464                 sbuf_printf(s, "rate: MCS %d\n", rate);
  465         } else {
  466                 rs = &ni->ni_rates;
  467                 rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  468                 sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
  469         }
  470 
  471         sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
  472         sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
  473         sbuf_printf(s, "success: %u\n", amn->amn_success);
  474         sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
  475         sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
  476         sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
  477 }

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