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/11.0/sys/net80211/ieee80211_amrr.c 302307 2016-07-01 19:58:13Z 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/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 ieee80211vap *,
   73                         const struct ieee80211_node *, int, 
   74                         void *, void *);
   75 static void     amrr_tx_update(const struct ieee80211vap *vap,
   76                         const struct ieee80211_node *, void *, void *, void *);
   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         amrr = vap->iv_rs = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr),
  121             M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  122         if (amrr == NULL) {
  123                 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
  124                 return;
  125         }
  126         amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
  127         amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
  128         amrr_setinterval(vap, 500 /* ms */);
  129         amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
  130 }
  131 
  132 static void
  133 amrr_deinit(struct ieee80211vap *vap)
  134 {
  135         IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
  136 }
  137 
  138 /*
  139  * Return whether 11n rates are possible.
  140  *
  141  * Some 11n devices may return HT information but no HT rates.
  142  * Thus, we shouldn't treat them as an 11n node.
  143  */
  144 static int
  145 amrr_node_is_11n(struct ieee80211_node *ni)
  146 {
  147 
  148         if (ni->ni_chan == NULL)
  149                 return (0);
  150         if (ni->ni_chan == IEEE80211_CHAN_ANYC)
  151                 return (0);
  152         if (IEEE80211_IS_CHAN_HT(ni->ni_chan) && ni->ni_htrates.rs_nrates == 0)
  153                 return (0);
  154         return (IEEE80211_IS_CHAN_HT(ni->ni_chan));
  155 }
  156 
  157 static void
  158 amrr_node_init(struct ieee80211_node *ni)
  159 {
  160         const struct ieee80211_rateset *rs = NULL;
  161         struct ieee80211vap *vap = ni->ni_vap;
  162         struct ieee80211_amrr *amrr = vap->iv_rs;
  163         struct ieee80211_amrr_node *amn;
  164         uint8_t rate;
  165 
  166         if (ni->ni_rctls == NULL) {
  167                 ni->ni_rctls = amn = IEEE80211_MALLOC(sizeof(struct ieee80211_amrr_node),
  168                     M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
  169                 if (amn == NULL) {
  170                         if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
  171                             "structure\n");
  172                         return;
  173                 }
  174         } else
  175                 amn = ni->ni_rctls;
  176         amn->amn_amrr = amrr;
  177         amn->amn_success = 0;
  178         amn->amn_recovery = 0;
  179         amn->amn_txcnt = amn->amn_retrycnt = 0;
  180         amn->amn_success_threshold = amrr->amrr_min_success_threshold;
  181 
  182         /* 11n or not? Pick the right rateset */
  183         if (amrr_node_is_11n(ni)) {
  184                 /* XXX ew */
  185                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  186                     "%s: 11n node", __func__);
  187                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  188         } else {
  189                 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  190                     "%s: non-11n node", __func__);
  191                 rs = &ni->ni_rates;
  192         }
  193 
  194         /* Initial rate - lowest */
  195         rate = rs->rs_rates[0];
  196 
  197         /* XXX clear the basic rate flag if it's not 11n */
  198         if (! amrr_node_is_11n(ni))
  199                 rate &= IEEE80211_RATE_VAL;
  200 
  201         /* pick initial rate from the rateset - HT or otherwise */
  202         /* Pick something low that's likely to succeed */
  203         for (amn->amn_rix = rs->rs_nrates - 1; amn->amn_rix > 0;
  204             amn->amn_rix--) {
  205                 /* legacy - anything < 36mbit, stop searching */
  206                 /* 11n - stop at MCS4 */
  207                 if (amrr_node_is_11n(ni)) {
  208                         if ((rs->rs_rates[amn->amn_rix] & 0x1f) < 4)
  209                                 break;
  210                 } else if ((rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) <= 72)
  211                         break;
  212         }
  213         rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  214 
  215         /* if the rate is an 11n rate, ensure the MCS bit is set */
  216         if (amrr_node_is_11n(ni))
  217                 rate |= IEEE80211_RATE_MCS;
  218 
  219         /* Assign initial rate from the rateset */
  220         ni->ni_txrate = rate;
  221         amn->amn_ticks = ticks;
  222 
  223         /* XXX TODO: we really need a rate-to-string method */
  224         /* XXX TODO: non-11n rate should be divided by two.. */
  225         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  226             "AMRR: nrates=%d, initial rate %s%d",
  227             rs->rs_nrates,
  228             amrr_node_is_11n(ni) ? "MCS " : "",
  229             rate & IEEE80211_RATE_VAL);
  230 }
  231 
  232 static void
  233 amrr_node_deinit(struct ieee80211_node *ni)
  234 {
  235         IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
  236 }
  237 
  238 static int
  239 amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
  240     struct ieee80211_node *ni)
  241 {
  242         int rix = amn->amn_rix;
  243         const struct ieee80211_rateset *rs = NULL;
  244 
  245         KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
  246 
  247         /* 11n or not? Pick the right rateset */
  248         if (amrr_node_is_11n(ni)) {
  249                 /* XXX ew */
  250                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  251         } else {
  252                 rs = &ni->ni_rates;
  253         }
  254 
  255         /* XXX TODO: we really need a rate-to-string method */
  256         /* XXX TODO: non-11n rate should be divided by two.. */
  257         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  258             "AMRR: current rate %d, txcnt=%d, retrycnt=%d",
  259             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  260             amn->amn_txcnt,
  261             amn->amn_retrycnt);
  262 
  263         /*
  264          * XXX This is totally bogus for 11n, as although high MCS
  265          * rates for each stream may be failing, the next stream
  266          * should be checked.
  267          *
  268          * Eg, if MCS5 is ok but MCS6/7 isn't, and we can go up to
  269          * MCS23, we should skip 6/7 and try 8 onwards.
  270          */
  271         if (is_success(amn)) {
  272                 amn->amn_success++;
  273                 if (amn->amn_success >= amn->amn_success_threshold &&
  274                     rix + 1 < rs->rs_nrates) {
  275                         amn->amn_recovery = 1;
  276                         amn->amn_success = 0;
  277                         rix++;
  278                         /* XXX TODO: we really need a rate-to-string method */
  279                         /* XXX TODO: non-11n rate should be divided by two.. */
  280                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  281                             "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
  282                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  283                             amn->amn_txcnt, amn->amn_retrycnt);
  284                 } else {
  285                         amn->amn_recovery = 0;
  286                 }
  287         } else if (is_failure(amn)) {
  288                 amn->amn_success = 0;
  289                 if (rix > 0) {
  290                         if (amn->amn_recovery) {
  291                                 amn->amn_success_threshold *= 2;
  292                                 if (amn->amn_success_threshold >
  293                                     amrr->amrr_max_success_threshold)
  294                                         amn->amn_success_threshold =
  295                                             amrr->amrr_max_success_threshold;
  296                         } else {
  297                                 amn->amn_success_threshold =
  298                                     amrr->amrr_min_success_threshold;
  299                         }
  300                         rix--;
  301                         /* XXX TODO: we really need a rate-to-string method */
  302                         /* XXX TODO: non-11n rate should be divided by two.. */
  303                         IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
  304                             "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
  305                             rs->rs_rates[rix] & IEEE80211_RATE_VAL,
  306                             amn->amn_txcnt, amn->amn_retrycnt);
  307                 }
  308                 amn->amn_recovery = 0;
  309         }
  310 
  311         /* reset counters */
  312         amn->amn_txcnt = 0;
  313         amn->amn_retrycnt = 0;
  314 
  315         return rix;
  316 }
  317 
  318 /*
  319  * Return the rate index to use in sending a data frame.
  320  * Update our internal state if it's been long enough.
  321  * If the rate changes we also update ni_txrate to match.
  322  */
  323 static int
  324 amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
  325 {
  326         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  327         struct ieee80211_amrr *amrr = amn->amn_amrr;
  328         const struct ieee80211_rateset *rs = NULL;
  329         int rix;
  330 
  331         /* 11n or not? Pick the right rateset */
  332         if (amrr_node_is_11n(ni)) {
  333                 /* XXX ew */
  334                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  335         } else {
  336                 rs = &ni->ni_rates;
  337         }
  338 
  339         if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
  340                 rix = amrr_update(amrr, amn, ni);
  341                 if (rix != amn->amn_rix) {
  342                         /* update public rate */
  343                         ni->ni_txrate = rs->rs_rates[rix];
  344                         /* XXX strip basic rate flag from txrate, if non-11n */
  345                         if (amrr_node_is_11n(ni))
  346                                 ni->ni_txrate |= IEEE80211_RATE_MCS;
  347                         else
  348                                 ni->ni_txrate &= IEEE80211_RATE_VAL;
  349                         amn->amn_rix = rix;
  350                 }
  351                 amn->amn_ticks = ticks;
  352         } else
  353                 rix = amn->amn_rix;
  354         return rix;
  355 }
  356 
  357 /*
  358  * Update statistics with tx complete status.  Ok is non-zero
  359  * if the packet is known to be ACK'd.  Retries has the number
  360  * retransmissions (i.e. xmit attempts - 1).
  361  */
  362 static void
  363 amrr_tx_complete(const struct ieee80211vap *vap,
  364     const struct ieee80211_node *ni, int ok,
  365     void *arg1, void *arg2 __unused)
  366 {
  367         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  368         int retries = *(int *)arg1;
  369 
  370         amn->amn_txcnt++;
  371         if (ok)
  372                 amn->amn_success++;
  373         amn->amn_retrycnt += retries;
  374 }
  375 
  376 /*
  377  * Set tx count/retry statistics explicitly.  Intended for
  378  * drivers that poll the device for statistics maintained
  379  * in the device.
  380  */
  381 static void
  382 amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
  383     void *arg1, void *arg2, void *arg3)
  384 {
  385         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  386         int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
  387 
  388         amn->amn_txcnt = txcnt;
  389         amn->amn_success = success;
  390         amn->amn_retrycnt = retrycnt;
  391 }
  392 
  393 static int
  394 amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
  395 {
  396         struct ieee80211vap *vap = arg1;
  397         struct ieee80211_amrr *amrr = vap->iv_rs;
  398         int msecs = ticks_to_msecs(amrr->amrr_interval);
  399         int error;
  400 
  401         error = sysctl_handle_int(oidp, &msecs, 0, req);
  402         if (error || !req->newptr)
  403                 return error;
  404         amrr_setinterval(vap, msecs);
  405         return 0;
  406 }
  407 
  408 static void
  409 amrr_sysctlattach(struct ieee80211vap *vap,
  410     struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
  411 {
  412         struct ieee80211_amrr *amrr = vap->iv_rs;
  413 
  414         SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  415             "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
  416             0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
  417         /* XXX bounds check values */
  418         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  419             "amrr_max_sucess_threshold", CTLFLAG_RW,
  420             &amrr->amrr_max_success_threshold, 0, "");
  421         SYSCTL_ADD_UINT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
  422             "amrr_min_sucess_threshold", CTLFLAG_RW,
  423             &amrr->amrr_min_success_threshold, 0, "");
  424 }
  425 
  426 static void
  427 amrr_node_stats(struct ieee80211_node *ni, struct sbuf *s)
  428 {
  429         int rate;
  430         struct ieee80211_amrr_node *amn = ni->ni_rctls;
  431         struct ieee80211_rateset *rs;
  432 
  433         /* XXX TODO: check locking? */
  434 
  435         /* XXX TODO: this should be a method */
  436         if (amrr_node_is_11n(ni)) {
  437                 rs = (struct ieee80211_rateset *) &ni->ni_htrates;
  438                 rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  439                 sbuf_printf(s, "rate: MCS %d\n", rate);
  440         } else {
  441                 rs = &ni->ni_rates;
  442                 rate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
  443                 sbuf_printf(s, "rate: %d Mbit\n", rate / 2);
  444         }
  445 
  446         sbuf_printf(s, "ticks: %d\n", amn->amn_ticks);
  447         sbuf_printf(s, "txcnt: %u\n", amn->amn_txcnt);
  448         sbuf_printf(s, "success: %u\n", amn->amn_success);
  449         sbuf_printf(s, "success_threshold: %u\n", amn->amn_success_threshold);
  450         sbuf_printf(s, "recovery: %u\n", amn->amn_recovery);
  451         sbuf_printf(s, "retry_cnt: %u\n", amn->amn_retrycnt);
  452 }

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