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ieee80211_amrr.c revision 1.3.18.1
      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 (at) FreeBSD.org>
      5  * Copyright (c) 2006
      6  *	Damien Bergamini <damien.bergamini (at) 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("$FreeBSD$");
     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 }
    478