1 /* $FreeBSD: head/sys/net80211/ieee80211_rssadapt.c 206358 2010-04-07 15:29:13Z rpaulo $ */ 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 <netproto/802_11/ieee80211_var.h> 45 #include <netproto/802_11/ieee80211_rssadapt.h> 46 #include <netproto/802_11/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 rs = kmalloc(sizeof(struct ieee80211_rssadapt), M_80211_RATECTL, 132 M_WAITOK|M_ZERO); 133 vap->iv_rs = rs; 134 rs->vap = vap; 135 rssadapt_setinterval(vap, 500 /* msecs */); 136 rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid); 137 } 138 139 static void 140 rssadapt_deinit(struct ieee80211vap *vap) 141 { 142 kfree(vap->iv_rs, M_80211_RATECTL); 143 } 144 145 static void 146 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra) 147 { 148 long interval; 149 150 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2; 151 ra->ra_nfail = ra->ra_nok = 0; 152 153 /* 154 * A node is eligible for its rate to be raised every 1/10 to 10 155 * seconds, more eligible in proportion to recent packet rates. 156 */ 157 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate)); 158 ra->ra_raise_interval = msecs_to_ticks(interval); 159 } 160 161 static void 162 rssadapt_node_init(struct ieee80211_node *ni) 163 { 164 struct ieee80211_rssadapt_node *ra; 165 struct ieee80211_rssadapt *rsa = ni->ni_vap->iv_rs; 166 const struct ieee80211_rateset *rs = &ni->ni_rates; 167 168 ra = kmalloc(sizeof(struct ieee80211_rssadapt_node), M_80211_RATECTL, 169 M_WAITOK|M_ZERO); 170 ni->ni_rctls = ra; 171 ra->ra_rs = rsa; 172 ra->ra_rates = *rs; 173 rssadapt_updatestats(ra); 174 175 /* pick initial rate */ 176 for (ra->ra_rix = rs->rs_nrates - 1; 177 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72; 178 ra->ra_rix--) 179 ; 180 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL; 181 ra->ra_ticks = ticks; 182 183 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 184 "RSSADAPT initial rate %d", ni->ni_txrate); 185 } 186 187 static void 188 rssadapt_node_deinit(struct ieee80211_node *ni) 189 { 190 191 kfree(ni->ni_rctls, M_80211_RATECTL); 192 } 193 194 static __inline int 195 bucket(int pktlen) 196 { 197 int i, top, thridx; 198 199 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 200 i < IEEE80211_RSSADAPT_BKTS; 201 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 202 thridx = i; 203 if (pktlen <= top) 204 break; 205 } 206 return thridx; 207 } 208 209 static int 210 rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg) 211 { 212 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 213 u_int pktlen = iarg; 214 const struct ieee80211_rateset *rs = &ra->ra_rates; 215 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 216 int rix, rssi; 217 218 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) { 219 rssadapt_updatestats(ra); 220 ra->ra_ticks = ticks; 221 } 222 223 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 224 225 /* XXX this is average rssi, should be using last value */ 226 rssi = ni->ni_ic->ic_node_getrssi(ni); 227 for (rix = rs->rs_nrates-1; rix >= 0; rix--) 228 if ((*thrs)[rix] < (rssi << 8)) 229 break; 230 if (rix != ra->ra_rix) { 231 /* update public rate */ 232 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL; 233 ra->ra_rix = rix; 234 235 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 236 "RSSADAPT new rate %d (pktlen %d rssi %d)", 237 ni->ni_txrate, pktlen, rssi); 238 } 239 return rix; 240 } 241 242 /* 243 * Adapt the data rate to suit the conditions. When a transmitted 244 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions, 245 * raise the RSS threshold for transmitting packets of similar length at 246 * the same data rate. 247 */ 248 static void 249 rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 250 { 251 uint16_t last_thr; 252 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 253 u_int rix; 254 255 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 256 257 rix = ra->ra_rix; 258 last_thr = (*thrs)[rix]; 259 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh, 260 last_thr, (rssi << 8)); 261 262 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 263 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n", 264 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 265 last_thr, (*thrs)[rix], rssi); 266 } 267 268 static void 269 rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi) 270 { 271 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 272 uint16_t newthr, oldthr; 273 int rix; 274 275 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 276 277 rix = ra->ra_rix; 278 if ((*thrs)[rix + 1] > (*thrs)[rix]) { 279 oldthr = (*thrs)[rix + 1]; 280 if ((*thrs)[rix] == 0) 281 newthr = (rssi << 8); 282 else 283 newthr = (*thrs)[rix]; 284 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay, 285 oldthr, newthr); 286 287 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 288 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n", 289 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 290 oldthr, newthr, rssi); 291 292 ra->ra_last_raise = ticks; 293 } 294 } 295 296 static void 297 rssadapt_tx_complete(const struct ieee80211vap *vap, 298 const struct ieee80211_node *ni, int success, void *arg1, void *arg2) 299 { 300 struct ieee80211_rssadapt_node *ra = ni->ni_rctls; 301 int pktlen = *(int *)arg1, rssi = *(int *)arg2; 302 303 if (success) { 304 ra->ra_nok++; 305 if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates && 306 (ticks - ra->ra_last_raise) >= ra->ra_raise_interval) 307 rssadapt_raise_rate(ra, pktlen, rssi); 308 } else { 309 ra->ra_nfail++; 310 rssadapt_lower_rate(ra, pktlen, rssi); 311 } 312 } 313 314 static int 315 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS) 316 { 317 struct ieee80211vap *vap = arg1; 318 struct ieee80211_rssadapt *rs = vap->iv_rs; 319 int msecs = ticks_to_msecs(rs->interval); 320 int error; 321 322 error = sysctl_handle_int(oidp, &msecs, 0, req); 323 wlan_serialize_enter(); 324 if (error == 0 && req->newptr) 325 rssadapt_setinterval(vap, msecs); 326 wlan_serialize_exit(); 327 328 return error; 329 } 330 331 static void 332 rssadapt_sysctlattach(struct ieee80211vap *vap, 333 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree) 334 { 335 336 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, 337 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap, 338 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)"); 339 } 340