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ieee80211_rssadapt.c revision 1.8.2.2
      1 /* $NetBSD: ieee80211_rssadapt.c,v 1.8.2.2 2004/08/03 10:54:21 skrll 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  * 3. The name of David Young may not be used to endorse or promote
     15  *    products derived from this software without specific prior
     16  *    written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
     19  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
     20  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
     21  * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
     22  * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     23  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
     24  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
     26  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
     27  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
     29  * OF SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/param.h>
     33 #include <sys/types.h>
     34 #include <sys/kernel.h>		/* for hz */
     35 #include <sys/sysctl.h>
     36 
     37 #include <net/if.h>
     38 #include <net/if_media.h>
     39 #include <net/if_ether.h>
     40 
     41 #include <net80211/ieee80211_var.h>
     42 #include <net80211/ieee80211.h>
     43 #include <net80211/ieee80211_compat.h>
     44 #include <net80211/ieee80211_rssadapt.h>
     45 
     46 #ifdef interpolate
     47 #undef interpolate
     48 #endif
     49 #define interpolate(parm, old, new) ((parm##_old * (old) + \
     50                                      (parm##_denom - parm##_old) * (new)) / \
     51 				    parm##_denom)
     52 
     53 #ifdef IEEE80211_DEBUG
     54 static	struct timeval lastrateadapt;	/* time of last rate adaptation msg */
     55 static	int currssadaptps = 0;		/* rate-adaptation msgs this second */
     56 static	int ieee80211_adaptrate = 4;	/* rate-adaptation max msgs/sec */
     57 
     58 #define RSSADAPT_DO_PRINT() \
     59 	((ieee80211_rssadapt_debug > 0) && \
     60 	 ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate))
     61 #define	RSSADAPT_PRINTF(X) \
     62 	if (RSSADAPT_DO_PRINT()) \
     63 		printf X
     64 
     65 int ieee80211_rssadapt_debug = 0;
     66 
     67 #else
     68 #define	RSSADAPT_DO_PRINT() (0)
     69 #define	RSSADAPT_PRINTF(X)
     70 #endif
     71 
     72 static struct ieee80211_rssadapt_expavgctl master_expavgctl = {
     73 	rc_decay_denom : 16,
     74 	rc_decay_old : 15,
     75 	rc_thresh_denom : 8,
     76 	rc_thresh_old : 4,
     77 	rc_avgrssi_denom : 8,
     78 	rc_avgrssi_old : 4
     79 };
     80 
     81 #ifdef __NetBSD__
     82 #ifdef IEEE80211_DEBUG
     83 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
     84 static int
     85 sysctl_ieee80211_rssadapt_debug(SYSCTLFN_ARGS)
     86 {
     87 	int error, t;
     88 	struct sysctlnode node;
     89 
     90 	node = *rnode;
     91 	t = *(int*)rnode->sysctl_data;
     92 	node.sysctl_data = &t;
     93 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
     94 	if (error || newp == NULL)
     95 		return (error);
     96 
     97 	if (t < 0 || t > 2)
     98 		return (EINVAL);
     99 	*(int*)rnode->sysctl_data = t;
    100 
    101 	return (0);
    102 }
    103 #endif /* IEEE80211_DEBUG */
    104 
    105 /* TBD factor with sysctl_ath_verify, sysctl_ieee80211_verify. */
    106 static int
    107 sysctl_ieee80211_rssadapt_expavgctl(SYSCTLFN_ARGS)
    108 {
    109 	struct ieee80211_rssadapt_expavgctl rc;
    110 	int error;
    111 	struct sysctlnode node;
    112 
    113 	node = *rnode;
    114 	rc = *(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data;
    115 	node.sysctl_data = &rc;
    116 	error = sysctl_lookup(SYSCTLFN_CALL(&node));
    117 	if (error || newp == NULL)
    118 		return (error);
    119 
    120 	if (rc.rc_decay_old < 0 ||
    121 	    rc.rc_decay_denom < rc.rc_decay_old)
    122 		return (EINVAL);
    123 
    124 	if (rc.rc_thresh_old < 0 ||
    125 	    rc.rc_thresh_denom < rc.rc_thresh_old)
    126 		return (EINVAL);
    127 
    128 	if (rc.rc_avgrssi_old < 0 ||
    129 	    rc.rc_avgrssi_denom < rc.rc_avgrssi_old)
    130 		return (EINVAL);
    131 
    132 	*(struct ieee80211_rssadapt_expavgctl *)rnode->sysctl_data = rc;
    133 
    134 	return (0);
    135 }
    136 
    137 /*
    138  * Setup sysctl(3) MIB, net.ieee80211.*
    139  *
    140  * TBD condition CTLFLAG_PERMANENT on being an LKM or not
    141  */
    142 SYSCTL_SETUP(sysctl_ieee80211_rssadapt,
    143     "sysctl ieee80211 rssadapt subtree setup")
    144 {
    145 	int rc;
    146 	struct sysctlnode *node;
    147 
    148 	if ((rc = sysctl_createv(clog, 0, NULL, &node,
    149 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "net", NULL,
    150 	    NULL, 0, NULL, 0, CTL_NET, CTL_EOL)) != 0)
    151 		goto err;
    152 
    153 	if ((rc = sysctl_createv(clog, 0, &node, &node,
    154 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "link", NULL,
    155 	    NULL, 0, NULL, 0, PF_LINK, CTL_EOL)) != 0)
    156 		goto err;
    157 
    158 	if ((rc = sysctl_createv(clog, 0, &node, &node,
    159 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "ieee80211", NULL,
    160 	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
    161 		goto err;
    162 
    163 	if ((rc = sysctl_createv(clog, 0, &node, &node,
    164 	    CTLFLAG_PERMANENT, CTLTYPE_NODE, "rssadapt",
    165 	    SYSCTL_DESCR("Received Signal Strength adaptation controls"),
    166 	    NULL, 0, NULL, 0, CTL_CREATE, CTL_EOL)) != 0)
    167 		goto err;
    168 
    169 #ifdef IEEE80211_DEBUG
    170 	/* control debugging printfs */
    171 	if ((rc = sysctl_createv(clog, 0, &node, NULL,
    172 	    CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_INT, "debug",
    173 	    SYSCTL_DESCR("Enable RSS adaptation debugging output"),
    174 	    sysctl_ieee80211_rssadapt_debug, 0, &ieee80211_rssadapt_debug, 0,
    175 	    CTL_CREATE, CTL_EOL)) != 0)
    176 		goto err;
    177 #endif /* IEEE80211_DEBUG */
    178 
    179 	/* control rate of decay for exponential averages */
    180 	if ((rc = sysctl_createv(clog, 0, &node, NULL,
    181 	    CTLFLAG_PERMANENT|CTLFLAG_READWRITE, CTLTYPE_STRUCT,
    182 	    "expavgctl", SYSCTL_DESCR("RSS exponential averaging control"),
    183 	    sysctl_ieee80211_rssadapt_expavgctl, 0,
    184 	    &master_expavgctl, sizeof(master_expavgctl), CTL_CREATE,
    185 	    CTL_EOL)) != 0)
    186 		goto err;
    187 
    188 	return;
    189 err:
    190 	printf("%s: sysctl_createv failed (rc = %d)\n", __func__, rc);
    191 }
    192 #endif /* __NetBSD__ */
    193 
    194 int
    195 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra,
    196     struct ieee80211_rateset *rs, struct ieee80211_frame *wh, u_int len,
    197     int fixed_rate, const char *dvname, int do_not_adapt)
    198 {
    199 	u_int16_t (*thrs)[IEEE80211_RATE_SIZE];
    200 	int flags = 0, i, rateidx = 0, thridx, top;
    201 
    202 	if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL)
    203 		flags |= IEEE80211_RATE_BASIC;
    204 
    205 	for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
    206 	     i < IEEE80211_RSSADAPT_BKTS;
    207 	     i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
    208 		thridx = i;
    209 		if (len <= top)
    210 			break;
    211 	}
    212 
    213 	thrs = &ra->ra_rate_thresh[thridx];
    214 
    215 	if (fixed_rate != -1) {
    216 		if ((rs->rs_rates[fixed_rate] & flags) == flags) {
    217 			rateidx = fixed_rate;
    218 			goto out;
    219 		}
    220 		flags |= IEEE80211_RATE_BASIC;
    221 		i = fixed_rate;
    222 	} else
    223 		i = rs->rs_nrates;
    224 
    225 	while (--i >= 0) {
    226 		rateidx = i;
    227 		if ((rs->rs_rates[i] & flags) != flags)
    228 			continue;
    229 		if (do_not_adapt)
    230 			break;
    231 		if ((*thrs)[i] < ra->ra_avg_rssi)
    232 			break;
    233 	}
    234 
    235 out:
    236 #ifdef IEEE80211_DEBUG
    237 	if (ieee80211_rssadapt_debug && dvname != NULL) {
    238 		printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n",
    239 		    dvname, ether_sprintf(wh->i_addr1), len,
    240 		    (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2,
    241 		    (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
    242 		    (*thrs)[rateidx], ra->ra_avg_rssi);
    243 	}
    244 #endif /* IEEE80211_DEBUG */
    245 	return rateidx;
    246 }
    247 
    248 void
    249 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra)
    250 {
    251 	long interval;
    252 
    253 	ra->ra_pktrate =
    254 	    (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2;
    255 	ra->ra_nfail = ra->ra_nok = 0;
    256 
    257 	/* a node is eligible for its rate to be raised every 1/10 to 10
    258 	 * seconds, more eligible in proportion to recent packet rates.
    259 	 */
    260 	interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate));
    261 	ra->ra_raise_interval.tv_sec = interval / (1000 * 1000);
    262 	ra->ra_raise_interval.tv_usec = interval % (1000 * 1000);
    263 }
    264 
    265 void
    266 ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni,
    267     struct ieee80211_rssadapt *ra, int rssi)
    268 {
    269 #ifdef IEEE80211_DEBUG
    270 	int last_avg_rssi = ra->ra_avg_rssi;
    271 #endif
    272 
    273 	ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi,
    274 	                              ra->ra_avg_rssi, (rssi << 8));
    275 
    276 	RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n",
    277 	    ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
    278 	    rssi, last_avg_rssi, ra->ra_avg_rssi));
    279 }
    280 
    281 /*
    282  * Adapt the data rate to suit the conditions.  When a transmitted
    283  * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions,
    284  * raise the RSS threshold for transmitting packets of similar length at
    285  * the same data rate.
    286  */
    287 void
    288 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic,
    289     struct ieee80211_node *ni, struct ieee80211_rssadapt *ra,
    290     struct ieee80211_rssdesc *id)
    291 {
    292 	struct ieee80211_rateset *rs = &ni->ni_rates;
    293 	u_int16_t last_thr;
    294 	u_int i, thridx, top;
    295 
    296 	ra->ra_nfail++;
    297 
    298 	if (id->id_rateidx >= rs->rs_nrates) {
    299 		RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: "
    300 		    "%s rate #%d > #%d out of bounds\n",
    301 		    ether_sprintf(ni->ni_macaddr), id->id_rateidx,
    302 		        rs->rs_nrates - 1));
    303 		return;
    304 	}
    305 
    306 	for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
    307 	     i < IEEE80211_RSSADAPT_BKTS;
    308 	     i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
    309 		thridx = i;
    310 		if (id->id_len <= top)
    311 			break;
    312 	}
    313 
    314 	last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx];
    315 	ra->ra_rate_thresh[thridx][id->id_rateidx] =
    316 	    interpolate(master_expavgctl.rc_thresh, last_thr,
    317 	                (id->id_rssi << 8));
    318 
    319 	RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n",
    320 	    ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr),
    321 	    id->id_rssi, id->id_len,
    322 	    (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2,
    323 	    (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10,
    324 	    last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx]));
    325 }
    326 
    327 void
    328 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic,
    329     struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id)
    330 {
    331 	u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr;
    332 	struct ieee80211_node *ni = id->id_node;
    333 	struct ieee80211_rateset *rs = &ni->ni_rates;
    334 	int i, rate, top;
    335 #ifdef IEEE80211_DEBUG
    336 	int j;
    337 #endif
    338 
    339 	ra->ra_nok++;
    340 
    341 	if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval))
    342 		return;
    343 
    344 	for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
    345 	     i < IEEE80211_RSSADAPT_BKTS;
    346 	     i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
    347 		thrs = &ra->ra_rate_thresh[i];
    348 		if (id->id_len <= top)
    349 			break;
    350 	}
    351 
    352 	if (id->id_rateidx + 1 < rs->rs_nrates &&
    353 	    (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) {
    354 		rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL);
    355 
    356 		RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ",
    357 		    ic->ic_if.if_xname,
    358 		    IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i),
    359 		    rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1]));
    360 		oldthr = (*thrs)[id->id_rateidx + 1];
    361 		if ((*thrs)[id->id_rateidx] == 0)
    362 			newthr = ra->ra_avg_rssi;
    363 		else
    364 			newthr = (*thrs)[id->id_rateidx];
    365 		(*thrs)[id->id_rateidx + 1] =
    366 		    interpolate(master_expavgctl.rc_decay, oldthr, newthr);
    367 
    368 		RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1]));
    369 	}
    370 
    371 #ifdef IEEE80211_DEBUG
    372 	if (RSSADAPT_DO_PRINT()) {
    373 		printf("%s: dst %s thresholds\n", ic->ic_if.if_xname,
    374 		    ether_sprintf(ni->ni_macaddr));
    375 		for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) {
    376 			printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER * i));
    377 			for (j = 0; j < rs->rs_nrates; j++) {
    378 				rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL);
    379 				printf(", T[%d.%d] = %d", rate / 2,
    380 				    rate * 5 % 10, ra->ra_rate_thresh[i][j]);
    381 			}
    382 			printf("\n");
    383 		}
    384 	}
    385 #endif /* IEEE80211_DEBUG */
    386 }
    387