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/kernel.h> 37 #include <sys/module.h> 38 #include <sys/socket.h> 39 #include <sys/sysctl.h> 40 41 #include <net/if.h> 42 #include <net/if_media.h> 43 44 #include <net80211/ieee80211_var.h> 45 #include <net80211/ieee80211_rssadapt.h> 46 #include <net80211/ieee80211_ratectl.h> 47 48 struct rssadapt_expavgctl { 49 /* RSS threshold decay. */ 50 u_int rc_decay_denom; 51 u_int rc_decay_old; 52 /* RSS threshold update. */ 53 u_int rc_thresh_denom; 54 u_int rc_thresh_old; 55 /* RSS average update. */ 56 u_int rc_avgrssi_denom; 57 u_int rc_avgrssi_old; 58 }; 59 60 static struct rssadapt_expavgctl master_expavgctl = { 61 .rc_decay_denom = 16, 62 .rc_decay_old = 15, 63 .rc_thresh_denom = 8, 64 .rc_thresh_old = 4, 65 .rc_avgrssi_denom = 8, 66 .rc_avgrssi_old = 4 67 }; 68 69 #ifdef interpolate 70 #undef interpolate 71 #endif 72 #define interpolate(parm, old, new) ((parm##_old * (old) + \ 73 (parm##_denom - parm##_old) * (new)) / \ 74 parm##_denom) 75 76 static void rssadapt_setinterval(const struct ieee80211vap *, int); 77 static void rssadapt_init(struct ieee80211vap *); 78 static void rssadapt_deinit(struct ieee80211vap *); 79 static void rssadapt_updatestats(struct ieee80211_rssadapt_node *); 80 static void rssadapt_node_init(struct ieee80211_node *); 81 static void rssadapt_node_deinit(struct ieee80211_node *); 82 static int rssadapt_rate(struct ieee80211_node *, void *, uint32_t); 83 static void rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int); 84 static void rssadapt_raise_rate(struct ieee80211_rssadapt_node *, 85 int, int); 86 static void rssadapt_tx_complete(const struct ieee80211vap *, 87 const struct ieee80211_node *, int, 88 void *, void *); 89 static void rssadapt_sysctlattach(struct ieee80211vap *, 90 struct sysctl_ctx_list *, struct sysctl_oid *); 91 92 /* number of references from net80211 layer */ 93 static int nrefs = 0; 94 95 static const struct ieee80211_ratectl rssadapt = { 96 .ir_name = "rssadapt", 97 .ir_attach = NULL, 98 .ir_detach = NULL, 99 .ir_init = rssadapt_init, 100 .ir_deinit = rssadapt_deinit, 101 .ir_node_init = rssadapt_node_init, 102 .ir_node_deinit = rssadapt_node_deinit, 103 .ir_rate = rssadapt_rate, 104 .ir_tx_complete = rssadapt_tx_complete, 105 .ir_tx_update = NULL, 106 .ir_setinterval = rssadapt_setinterval, 107 }; 108 IEEE80211_RATECTL_MODULE(rssadapt, 1); 109 IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt); 110 111 static void 112 rssadapt_setinterval(const struct ieee80211vap *vap, int msecs) 113 { 114 struct ieee80211_rssadapt *rs = vap->iv_rs; 115 int t; 116 117 if (msecs < 100) 118 msecs = 100; 119 t = msecs_to_ticks(msecs); 120 rs->interval = (t < 1) ? 1 : t; 121 } 122 123 static void 124 rssadapt_init(struct ieee80211vap *vap) 125 { 126 struct ieee80211_rssadapt *rs; 127 128 KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized", 129 __func__)); 130 131 vap->iv_rs = rs = malloc(sizeof(struct ieee80211_rssadapt), 132 M_80211_RATECTL, M_NOWAIT|M_ZERO); 133 if (rs == NULL) { 134 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n"); 135 return; 136 } 137 rs->vap = vap; 138 rssadapt_setinterval(vap, 500 /* msecs */); 139 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid); 140 } 141 142 static void 143 rssadapt_deinit(struct ieee80211vap *vap) 144 { 145 free(vap->iv_rs, M_80211_RATECTL); 146 } 147 148 static void 149 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra) 150 { 151 long interval; 152 153 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2; 154 ra->ra_nfail = ra->ra_nok = 0; 155 156 /* 157 * A node is eligible for its rate to be raised every 1/10 to 10 158 * seconds, more eligible in proportion to recent packet rates. 159 */ 160 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate)); 161 ra->ra_raise_interval = msecs_to_ticks(interval); 162 } 163 164 static void 165 rssadapt_node_init(struct ieee80211_node *ni) 166 { 167 struct ieee80211_rssadapt_node *ra; 168 struct ieee80211vap *vap = ni->ni_vap; 169 struct ieee80211_rssadapt *rsa = vap->iv_rs; 170 const struct ieee80211_rateset *rs = &ni->ni_rates; 171 172 if (ni->ni_rctls == NULL) { 173 ni->ni_rctls = ra = 174 malloc(sizeof(struct ieee80211_rssadapt_node), 175 M_80211_RATECTL, M_NOWAIT|M_ZERO); 176 if (ra == NULL) { 177 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl " 178 "structure\n"); 179 return; 180 } 181 } else 182 ra = ni->ni_rctls; 183 ra->ra_rs = rsa; 184 ra->ra_rates = *rs; 185 rssadapt_updatestats(ra); 186 187 /* pick initial rate */ 188 for (ra->ra_rix = rs->rs_nrates - 1; 189 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72; 190 ra->ra_rix--) 191 ; 192 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL; 193 ra->ra_ticks = ticks; 194 195 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 196 "RSSADAPT initial rate %d", ni->ni_txrate); 197 } 198 199 static void 200 rssadapt_node_deinit(struct ieee80211_node *ni) 201 { 202 203 free(ni->ni_rctls, M_80211_RATECTL); 204 } 205 206 static __inline int 207 bucket(int pktlen) 208 { 209 int i, top, thridx; 210 211 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 212 i < IEEE80211_RSSADAPT_BKTS; 213 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 214 thridx = i; 215 if (pktlen <= top) 216 break; 217 } 218 return thridx; 219 } 220 221 static int 222 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg) 223 { 224 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 225 u_int pktlen = iarg; 226 const struct ieee80211_rateset *rs = &ra->ra_rates; 227 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 228 int rix, rssi; 229 230 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) { 231 rssadapt_updatestats(ra); 232 ra->ra_ticks = ticks; 233 } 234 235 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 236 237 /* XXX this is average rssi, should be using last value */ 238 rssi = ni->ni_ic->ic_node_getrssi(ni); 239 for (rix = rs->rs_nrates-1; rix >= 0; rix--) 240 if ((*thrs)[rix] < (rssi << 8)) 241 break; 242 if (rix != ra->ra_rix) { 243 /* update public rate */ 244 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL; 245 ra->ra_rix = rix; 246 247 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 248 "RSSADAPT new rate %d (pktlen %d rssi %d)", 249 ni->ni_txrate, pktlen, rssi); 250 } 251 return rix; 252 } 253 254 /* 255 * Adapt the data rate to suit the conditions. When a transmitted 256 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions, 257 * raise the RSS threshold for transmitting packets of similar length at 258 * the same data rate. 259 */ 260 static void 261 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 262 { 263 uint16_t last_thr; 264 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 265 u_int rix; 266 267 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 268 269 rix = ra->ra_rix; 270 last_thr = (*thrs)[rix]; 271 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh, 272 last_thr, (rssi << 8)); 273 274 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 275 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n", 276 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 277 last_thr, (*thrs)[rix], rssi); 278 } 279 280 static void 281 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 282 { 283 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 284 uint16_t newthr, oldthr; 285 int rix; 286 287 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 288 289 rix = ra->ra_rix; 290 if ((*thrs)[rix + 1] > (*thrs)[rix]) { 291 oldthr = (*thrs)[rix + 1]; 292 if ((*thrs)[rix] == 0) 293 newthr = (rssi << 8); 294 else 295 newthr = (*thrs)[rix]; 296 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay, 297 oldthr, newthr); 298 299 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 300 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n", 301 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 302 oldthr, newthr, rssi); 303 304 ra->ra_last_raise = ticks; 305 } 306 } 307 308 static void 309 rssadapt_tx_complete(const struct ieee80211vap *vap, 310 const struct ieee80211_node *ni, int success, void *arg1, void *arg2) 311 { 312 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 313 int pktlen = *(int *)arg1, rssi = *(int *)arg2; 314 315 if (success) { 316 ra->ra_nok++; 317 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates && 318 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval) 319 rssadapt_raise_rate(ra, pktlen, rssi); 320 } else { 321 ra->ra_nfail++; 322 rssadapt_lower_rate(ra, pktlen, rssi); 323 } 324 } 325 326 static int 327 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS) 328 { 329 struct ieee80211vap *vap = arg1; 330 struct ieee80211_rssadapt *rs = vap->iv_rs; 331 int msecs = ticks_to_msecs(rs->interval); 332 int error; 333 334 error = sysctl_handle_int(oidp, &msecs, 0, req); 335 if (error || !req->newptr) 336 return error; 337 rssadapt_setinterval(vap, msecs); 338 return 0; 339 } 340 341 static void 342 rssadapt_sysctlattach(struct ieee80211vap *vap, 343 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree) 344 { 345 346 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, 347 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap, 348 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)"); 349 } 350