1 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */ 2 /*- 3 * SPDX-License-Identifier: BSD-3-Clause 4 * 5 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org> 6 * Copyright (c) 2003, 2004 David Young. All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or 9 * without modification, are permitted provided that the following 10 * conditions are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above 14 * copyright notice, this list of conditions and the following 15 * disclaimer in the documentation and/or other materials provided 16 * with the distribution. 17 * 3. The name of David Young may not be used to endorse or promote 18 * products derived from this software without specific prior 19 * written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, 23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A 24 * PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL David 25 * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED 27 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 29 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY 32 * OF SUCH DAMAGE. 33 */ 34 #include "opt_wlan.h" 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/kernel.h> 39 #include <sys/malloc.h> 40 #include <sys/module.h> 41 #include <sys/socket.h> 42 #include <sys/sysctl.h> 43 44 #include <net/if.h> 45 #include <net/if_var.h> 46 #include <net/if_media.h> 47 #include <net/ethernet.h> 48 49 #include <net80211/ieee80211_var.h> 50 #include <net80211/ieee80211_rssadapt.h> 51 #include <net80211/ieee80211_ratectl.h> 52 53 struct rssadapt_expavgctl { 54 /* RSS threshold decay. */ 55 u_int rc_decay_denom; 56 u_int rc_decay_old; 57 /* RSS threshold update. */ 58 u_int rc_thresh_denom; 59 u_int rc_thresh_old; 60 /* RSS average update. */ 61 u_int rc_avgrssi_denom; 62 u_int rc_avgrssi_old; 63 }; 64 65 static struct rssadapt_expavgctl master_expavgctl = { 66 .rc_decay_denom = 16, 67 .rc_decay_old = 15, 68 .rc_thresh_denom = 8, 69 .rc_thresh_old = 4, 70 .rc_avgrssi_denom = 8, 71 .rc_avgrssi_old = 4 72 }; 73 74 #ifdef interpolate 75 #undef interpolate 76 #endif 77 #define interpolate(parm, old, new) ((parm##_old * (old) + \ 78 (parm##_denom - parm##_old) * (new)) / \ 79 parm##_denom) 80 81 static void rssadapt_setinterval(const struct ieee80211vap *, int); 82 static void rssadapt_init(struct ieee80211vap *); 83 static void rssadapt_deinit(struct ieee80211vap *); 84 static void rssadapt_updatestats(struct ieee80211_rssadapt_node *); 85 static void rssadapt_node_init(struct ieee80211_node *); 86 static void rssadapt_node_deinit(struct ieee80211_node *); 87 static int rssadapt_rate(struct ieee80211_node *, void *, uint32_t); 88 static void rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int); 89 static void rssadapt_raise_rate(struct ieee80211_rssadapt_node *, 90 int, int); 91 static void rssadapt_tx_complete(const struct ieee80211_node *, 92 const struct ieee80211_ratectl_tx_status *); 93 static void rssadapt_sysctlattach(struct ieee80211vap *, 94 struct sysctl_ctx_list *, struct sysctl_oid *); 95 96 /* number of references from net80211 layer */ 97 static int nrefs = 0; 98 99 static const struct ieee80211_ratectl rssadapt = { 100 .ir_name = "rssadapt", 101 .ir_attach = NULL, 102 .ir_detach = NULL, 103 .ir_init = rssadapt_init, 104 .ir_deinit = rssadapt_deinit, 105 .ir_node_init = rssadapt_node_init, 106 .ir_node_deinit = rssadapt_node_deinit, 107 .ir_rate = rssadapt_rate, 108 .ir_tx_complete = rssadapt_tx_complete, 109 .ir_tx_update = NULL, 110 .ir_setinterval = rssadapt_setinterval, 111 }; 112 IEEE80211_RATECTL_MODULE(rssadapt, 1); 113 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt); 114 115 static void 116 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs) 117 { 118 struct ieee80211_rssadapt *rs = vap->iv_rs; 119 120 if (!rs) 121 return; 122 123 if (msecs < 100) 124 msecs = 100; 125 rs->interval = msecs_to_ticks(msecs); 126 } 127 128 static void 129 rssadapt_init(struct ieee80211vap *vap) 130 { 131 struct ieee80211_rssadapt *rs; 132 133 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized", 134 __func__)); 135 136 nrefs++; /* XXX locking */ 137 vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt), 138 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 139 if (rs == NULL) { 140 net80211_vap_printf(vap, "couldn't alloc ratectl structure\n"); 141 return; 142 } 143 rs->vap = vap; 144 rssadapt_setinterval(vap, 500 /* msecs */); 145 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid); 146 } 147 148 static void 149 rssadapt_deinit(struct ieee80211vap *vap) 150 { 151 IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL); 152 KASSERT(nrefs > 0, ("imbalanced attach/detach")); 153 nrefs--; /* XXX locking */ 154 } 155 156 static void 157 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra) 158 { 159 long interval; 160 161 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2; 162 ra->ra_nfail = ra->ra_nok = 0; 163 164 /* 165 * A node is eligible for its rate to be raised every 1/10 to 10 166 * seconds, more eligible in proportion to recent packet rates. 167 */ 168 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate)); 169 ra->ra_raise_interval = msecs_to_ticks(interval); 170 } 171 172 static void 173 rssadapt_node_init(struct ieee80211_node *ni) 174 { 175 struct ieee80211_rssadapt_node *ra; 176 struct ieee80211vap *vap = ni->ni_vap; 177 struct ieee80211_rssadapt *rsa = vap->iv_rs; 178 const struct ieee80211_rateset *rs = &ni->ni_rates; 179 180 if (!rsa) { 181 net80211_vap_printf(vap, 182 "ratectl structure was not allocated, " 183 "per-node structure allocation skipped\n"); 184 return; 185 } 186 187 if (ni->ni_rctls == NULL) { 188 ni->ni_rctls = ra = 189 IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node), 190 M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO); 191 if (ra == NULL) { 192 net80211_vap_printf(vap, 193 "couldn't alloc per-node ratectl structure\n"); 194 return; 195 } 196 } else 197 ra = ni->ni_rctls; 198 ra->ra_rs = rsa; 199 ra->ra_rates = *rs; 200 rssadapt_updatestats(ra); 201 202 /* pick initial rate */ 203 for (ra->ra_rix = rs->rs_nrates - 1; 204 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72; 205 ra->ra_rix--) 206 ; 207 ieee80211_node_set_txrate_dot11rate(ni, 208 rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL); 209 ra->ra_ticks = ticks; 210 211 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 212 "RSSADAPT initial rate %d Mbit/s", 213 ieee80211_node_get_txrate_kbit(ni) / 1000); 214 } 215 216 static void 217 rssadapt_node_deinit(struct ieee80211_node *ni) 218 { 219 220 IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL); 221 } 222 223 static __inline int 224 bucket(int pktlen) 225 { 226 int i, top, thridx; 227 228 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 229 i < IEEE80211_RSSADAPT_BKTS; 230 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 231 thridx = i; 232 if (pktlen <= top) 233 break; 234 } 235 return thridx; 236 } 237 238 static int 239 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg) 240 { 241 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 242 u_int pktlen = iarg; 243 const struct ieee80211_rateset *rs; 244 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 245 int rix, rssi; 246 247 /* XXX should return -1 here, but drivers may not expect this... */ 248 if (!ra) 249 { 250 ieee80211_node_set_txrate_dot11rate(ni, 251 ni->ni_rates.rs_rates[0]); 252 return 0; 253 } 254 255 rs = &ra->ra_rates; 256 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) { 257 rssadapt_updatestats(ra); 258 ra->ra_ticks = ticks; 259 } 260 261 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 262 263 /* XXX this is average rssi, should be using last value */ 264 rssi = ni->ni_ic->ic_node_getrssi(ni); 265 for (rix = rs->rs_nrates-1; rix >= 0; rix--) 266 if ((*thrs)[rix] < (rssi << 8)) 267 break; 268 if (rix != ra->ra_rix) { 269 /* update public rate */ 270 ieee80211_node_set_txrate_dot11rate(ni, 271 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL); 272 ra->ra_rix = rix; 273 274 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 275 "RSSADAPT new rate %d Mbit/s (pktlen %d rssi %d)", 276 ieee80211_node_get_txrate_kbit(ni) / 1000, pktlen, rssi); 277 } 278 return rix; 279 } 280 281 /* 282 * Adapt the data rate to suit the conditions. When a transmitted 283 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions, 284 * raise the RSS threshold for transmitting packets of similar length at 285 * the same data rate. 286 */ 287 static void 288 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 289 { 290 uint16_t last_thr; 291 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 292 u_int rix; 293 294 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 295 296 rix = ra->ra_rix; 297 last_thr = (*thrs)[rix]; 298 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh, 299 last_thr, (rssi << 8)); 300 301 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 302 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n", 303 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 304 last_thr, (*thrs)[rix], rssi); 305 } 306 307 static void 308 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 309 { 310 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 311 uint16_t newthr, oldthr; 312 int rix; 313 314 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 315 316 rix = ra->ra_rix; 317 if ((*thrs)[rix + 1] > (*thrs)[rix]) { 318 oldthr = (*thrs)[rix + 1]; 319 if ((*thrs)[rix] == 0) 320 newthr = (rssi << 8); 321 else 322 newthr = (*thrs)[rix]; 323 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay, 324 oldthr, newthr); 325 326 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 327 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n", 328 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 329 oldthr, newthr, rssi); 330 331 ra->ra_last_raise = ticks; 332 } 333 } 334 335 static void 336 rssadapt_tx_complete(const struct ieee80211_node *ni, 337 const struct ieee80211_ratectl_tx_status *status) 338 { 339 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 340 int pktlen, rssi; 341 342 if (!ra) 343 return; 344 345 if ((status->flags & 346 (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI)) != 347 (IEEE80211_RATECTL_STATUS_PKTLEN|IEEE80211_RATECTL_STATUS_RSSI)) 348 return; 349 350 pktlen = status->pktlen; 351 rssi = status->rssi; 352 353 if (status->status == IEEE80211_RATECTL_TX_SUCCESS) { 354 ra->ra_nok++; 355 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates && 356 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval) 357 rssadapt_raise_rate(ra, pktlen, rssi); 358 } else { 359 ra->ra_nfail++; 360 rssadapt_lower_rate(ra, pktlen, rssi); 361 } 362 } 363 364 static int 365 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS) 366 { 367 struct ieee80211vap *vap = arg1; 368 struct ieee80211_rssadapt *rs = vap->iv_rs; 369 int msecs, error; 370 371 if (!rs) 372 return ENOMEM; 373 374 msecs = ticks_to_msecs(rs->interval); 375 error = sysctl_handle_int(oidp, &msecs, 0, req); 376 if (error || !req->newptr) 377 return error; 378 rssadapt_setinterval(vap, msecs); 379 return 0; 380 } 381 382 static void 383 rssadapt_sysctlattach(struct ieee80211vap *vap, 384 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree) 385 { 386 387 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, 388 "rssadapt_rate_interval", 389 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, vap, 0, 390 rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)"); 391 } 392