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