1 /* $DragonFly$ */ 2 /* $FreeBSD: head/sys/net80211/ieee80211_rssadapt.c 178354 2008-04-20 20:35:46Z sam $ */ 3 /* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */ 4 /*- 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 #include <net/route.h> 44 45 #include <netproto/802_11/ieee80211_var.h> 46 #include <netproto/802_11/ieee80211_rssadapt.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_sysctlattach(struct ieee80211_rssadapt *rs, 77 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree); 78 79 /* number of references from net80211 layer */ 80 static int nrefs = 0; 81 82 void 83 ieee80211_rssadapt_setinterval(struct ieee80211_rssadapt *rs, int msecs) 84 { 85 int t; 86 87 if (msecs < 100) 88 msecs = 100; 89 t = msecs_to_ticks(msecs); 90 rs->interval = (t < 1) ? 1 : t; 91 } 92 93 void 94 ieee80211_rssadapt_init(struct ieee80211_rssadapt *rs, struct ieee80211vap *vap, int interval) 95 { 96 rs->vap = vap; 97 ieee80211_rssadapt_setinterval(rs, interval); 98 99 rssadapt_sysctlattach(rs, vap->iv_sysctl, vap->iv_oid); 100 } 101 102 void 103 ieee80211_rssadapt_cleanup(struct ieee80211_rssadapt *rs) 104 { 105 } 106 107 static void 108 rssadapt_updatestats(struct ieee80211_rssadapt_node *ra) 109 { 110 long interval; 111 112 ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2; 113 ra->ra_nfail = ra->ra_nok = 0; 114 115 /* 116 * A node is eligible for its rate to be raised every 1/10 to 10 117 * seconds, more eligible in proportion to recent packet rates. 118 */ 119 interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate)); 120 ra->ra_raise_interval = msecs_to_ticks(interval); 121 } 122 123 void 124 ieee80211_rssadapt_node_init(struct ieee80211_rssadapt *rsa, 125 struct ieee80211_rssadapt_node *ra, struct ieee80211_node *ni) 126 { 127 const struct ieee80211_rateset *rs = &ni->ni_rates; 128 129 ra->ra_rs = rsa; 130 ra->ra_rates = *rs; 131 rssadapt_updatestats(ra); 132 133 /* pick initial rate */ 134 for (ra->ra_rix = rs->rs_nrates - 1; 135 ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72; 136 ra->ra_rix--) 137 ; 138 ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL; 139 ra->ra_ticks = ticks; 140 141 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 142 "RSSADAPT initial rate %d", ni->ni_txrate); 143 } 144 145 static __inline int 146 bucket(int pktlen) 147 { 148 int i, top, thridx; 149 150 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 151 i < IEEE80211_RSSADAPT_BKTS; 152 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 153 thridx = i; 154 if (pktlen <= top) 155 break; 156 } 157 return thridx; 158 } 159 160 int 161 ieee80211_rssadapt_choose(struct ieee80211_node *ni, 162 struct ieee80211_rssadapt_node *ra, u_int pktlen) 163 { 164 const struct ieee80211_rateset *rs = &ra->ra_rates; 165 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 166 int rix, rssi; 167 168 if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) { 169 rssadapt_updatestats(ra); 170 ra->ra_ticks = ticks; 171 } 172 173 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 174 175 /* XXX this is average rssi, should be using last value */ 176 rssi = ni->ni_ic->ic_node_getrssi(ni); 177 for (rix = rs->rs_nrates-1; rix >= 0; rix--) 178 if ((*thrs)[rix] < (rssi << 8)) 179 break; 180 if (rix != ra->ra_rix) { 181 /* update public rate */ 182 ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL; 183 ra->ra_rix = rix; 184 185 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni, 186 "RSSADAPT new rate %d (pktlen %d rssi %d)", 187 ni->ni_txrate, pktlen, rssi); 188 } 189 return rix; 190 } 191 192 /* 193 * Adapt the data rate to suit the conditions. When a transmitted 194 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions, 195 * raise the RSS threshold for transmitting packets of similar length at 196 * the same data rate. 197 */ 198 void 199 ieee80211_rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, 200 int pktlen, int rssi) 201 { 202 uint16_t last_thr; 203 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 204 u_int rix; 205 206 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 207 208 rix = ra->ra_rix; 209 last_thr = (*thrs)[rix]; 210 (*thrs)[rix] = interpolate(master_expavgctl.rc_thresh, 211 last_thr, (rssi << 8)); 212 213 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 214 "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n", 215 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 216 last_thr, (*thrs)[rix], rssi); 217 } 218 219 void 220 ieee80211_rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, 221 int pktlen, int rssi) 222 { 223 uint16_t (*thrs)[IEEE80211_RATE_SIZE]; 224 uint16_t newthr, oldthr; 225 int rix; 226 227 thrs = &ra->ra_rate_thresh[bucket(pktlen)]; 228 229 rix = ra->ra_rix; 230 if ((*thrs)[rix + 1] > (*thrs)[rix]) { 231 oldthr = (*thrs)[rix + 1]; 232 if ((*thrs)[rix] == 0) 233 newthr = (rssi << 8); 234 else 235 newthr = (*thrs)[rix]; 236 (*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay, 237 oldthr, newthr); 238 239 IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL, 240 "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n", 241 ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL, 242 oldthr, newthr, rssi); 243 244 ra->ra_last_raise = ticks; 245 } 246 } 247 248 static int 249 rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS) 250 { 251 struct ieee80211_rssadapt *rs = arg1; 252 int msecs = ticks_to_msecs(rs->interval); 253 int error; 254 255 error = sysctl_handle_int(oidp, &msecs, 0, req); 256 if (error || !req->newptr) 257 return error; 258 ieee80211_rssadapt_setinterval(rs, msecs); 259 return 0; 260 } 261 262 static void 263 rssadapt_sysctlattach(struct ieee80211_rssadapt *rs, 264 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree) 265 { 266 267 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO, 268 "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, rs, 269 0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)"); 270 } 271 272 /* 273 * Module glue. 274 */ 275 IEEE80211_RATE_MODULE(rssadapt, 1); 276