1 /* $OpenBSD: ieee80211_rssadapt.c,v 1.7 2008/09/01 20:00:19 damien Exp $ */ 2 /* $NetBSD: ieee80211_rssadapt.c,v 1.7 2004/05/25 04:33:59 dyoung Exp $ */ 3 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 34 #include <sys/param.h> 35 #include <sys/kernel.h> 36 #include <sys/socket.h> 37 #include <sys/sysctl.h> 38 39 #include <net/if.h> 40 #include <net/if_media.h> 41 42 #ifdef INET 43 #include <netinet/in.h> 44 #include <netinet/if_ether.h> 45 #endif 46 47 #include <net80211/ieee80211_var.h> 48 #include <net80211/ieee80211_rssadapt.h> 49 50 #ifdef interpolate 51 #undef interpolate 52 #endif 53 #define interpolate(parm, old, new) \ 54 ((parm##_old * (old) + \ 55 (parm##_denom - parm##_old) * (new)) / parm##_denom) 56 57 #ifdef IEEE80211_DEBUG 58 static struct timeval lastrateadapt; /* time of last rate adaptation msg */ 59 static int currssadaptps = 0; /* rate-adaptation msgs this second */ 60 static int ieee80211_adaptrate = 4; /* rate-adaptation max msgs/sec */ 61 62 #define RSSADAPT_DO_PRINT() \ 63 ((ieee80211_rssadapt_debug > 0) && \ 64 ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate)) 65 #define RSSADAPT_PRINTF(X) \ 66 if (RSSADAPT_DO_PRINT()) \ 67 printf X 68 69 int ieee80211_rssadapt_debug = 0; 70 71 #else 72 #define RSSADAPT_DO_PRINT() (0) 73 #define RSSADAPT_PRINTF(X) 74 #endif 75 76 static const struct ieee80211_rssadapt_expavgctl master_expavgctl = { 77 .rc_decay_denom = 16, 78 .rc_decay_old = 15, 79 .rc_thresh_denom = 8, 80 .rc_thresh_old = 4, 81 .rc_avgrssi_denom = 8, 82 .rc_avgrssi_old = 4 83 }; 84 85 int 86 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra, 87 const struct ieee80211_rateset *rs, const struct ieee80211_frame *wh, 88 u_int len, int fixed_rate, const char *dvname, int do_not_adapt) 89 { 90 u_int16_t (*thrs)[IEEE80211_RATE_SIZE]; 91 int flags = 0, i, rateidx = 0, thridx, top; 92 93 if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL) 94 flags |= IEEE80211_RATE_BASIC; 95 96 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 97 i < IEEE80211_RSSADAPT_BKTS; 98 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 99 thridx = i; 100 if (len <= top) 101 break; 102 } 103 104 thrs = &ra->ra_rate_thresh[thridx]; 105 106 if (fixed_rate != -1) { 107 if ((rs->rs_rates[fixed_rate] & flags) == flags) { 108 rateidx = fixed_rate; 109 goto out; 110 } 111 flags |= IEEE80211_RATE_BASIC; 112 i = fixed_rate; 113 } else 114 i = rs->rs_nrates; 115 116 while (--i >= 0) { 117 rateidx = i; 118 if ((rs->rs_rates[i] & flags) != flags) 119 continue; 120 if (do_not_adapt) 121 break; 122 if ((*thrs)[i] < ra->ra_avg_rssi) 123 break; 124 } 125 126 out: 127 #ifdef IEEE80211_DEBUG 128 if (ieee80211_rssadapt_debug && dvname != NULL) { 129 printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n", 130 dvname, ether_sprintf((u_int8_t *)wh->i_addr1), len, 131 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2, 132 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10, 133 (*thrs)[rateidx], ra->ra_avg_rssi); 134 } 135 #endif /* IEEE80211_DEBUG */ 136 return rateidx; 137 } 138 139 void 140 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra) 141 { 142 long interval; 143 144 ra->ra_pktrate = 145 (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2; 146 ra->ra_nfail = ra->ra_nok = 0; 147 148 /* a node is eligible for its rate to be raised every 1/10 to 10 149 * seconds, more eligible in proportion to recent packet rates. 150 */ 151 interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate)); 152 ra->ra_raise_interval.tv_sec = interval / (1000 * 1000); 153 ra->ra_raise_interval.tv_usec = interval % (1000 * 1000); 154 } 155 156 void 157 ieee80211_rssadapt_input(struct ieee80211com *ic, 158 const struct ieee80211_node *ni, struct ieee80211_rssadapt *ra, int rssi) 159 { 160 #ifdef IEEE80211_DEBUG 161 int last_avg_rssi = ra->ra_avg_rssi; 162 #endif 163 164 ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi, 165 ra->ra_avg_rssi, (rssi << 8)); 166 167 RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n", 168 ic->ic_if.if_xname, ether_sprintf((u_int8_t *)ni->ni_macaddr), 169 rssi, last_avg_rssi, ra->ra_avg_rssi)); 170 } 171 172 /* 173 * Adapt the data rate to suit the conditions. When a transmitted 174 * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions, 175 * raise the RSS threshold for transmitting packets of similar length at 176 * the same data rate. 177 */ 178 void 179 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic, 180 const struct ieee80211_node *ni, struct ieee80211_rssadapt *ra, 181 const struct ieee80211_rssdesc *id) 182 { 183 const struct ieee80211_rateset *rs = &ni->ni_rates; 184 u_int16_t last_thr; 185 u_int i, thridx, top; 186 187 ra->ra_nfail++; 188 189 if (id->id_rateidx >= rs->rs_nrates) { 190 RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: " 191 "%s rate #%d > #%d out of bounds\n", 192 ether_sprintf((u_int8_t *)ni->ni_macaddr), id->id_rateidx, 193 rs->rs_nrates - 1)); 194 return; 195 } 196 197 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 198 i < IEEE80211_RSSADAPT_BKTS; 199 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 200 thridx = i; 201 if (id->id_len <= top) 202 break; 203 } 204 205 last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx]; 206 ra->ra_rate_thresh[thridx][id->id_rateidx] = 207 interpolate(master_expavgctl.rc_thresh, last_thr, 208 (id->id_rssi << 8)); 209 210 RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n", 211 ic->ic_if.if_xname, ether_sprintf((u_int8_t *)ni->ni_macaddr), 212 id->id_rssi, id->id_len, 213 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2, 214 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10, 215 last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx])); 216 } 217 218 void 219 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic, 220 struct ieee80211_rssadapt *ra, const struct ieee80211_rssdesc *id) 221 { 222 u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr; 223 const struct ieee80211_node *ni = id->id_node; 224 const struct ieee80211_rateset *rs = &ni->ni_rates; 225 int i, rate, top; 226 #ifdef IEEE80211_DEBUG 227 int j; 228 #endif 229 230 ra->ra_nok++; 231 232 if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval)) 233 return; 234 235 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 236 i < IEEE80211_RSSADAPT_BKTS; 237 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 238 thrs = &ra->ra_rate_thresh[i]; 239 if (id->id_len <= top) 240 break; 241 } 242 243 if (id->id_rateidx + 1 < rs->rs_nrates && 244 (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) { 245 rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL); 246 247 RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ", 248 ic->ic_if.if_xname, IEEE80211_RSSADAPT_BKT0 << 249 (IEEE80211_RSSADAPT_BKTPOWER * i), 250 rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1])); 251 oldthr = (*thrs)[id->id_rateidx + 1]; 252 if ((*thrs)[id->id_rateidx] == 0) 253 newthr = ra->ra_avg_rssi; 254 else 255 newthr = (*thrs)[id->id_rateidx]; 256 (*thrs)[id->id_rateidx + 1] = 257 interpolate(master_expavgctl.rc_decay, oldthr, newthr); 258 259 RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1])); 260 } 261 262 #ifdef IEEE80211_DEBUG 263 if (RSSADAPT_DO_PRINT()) { 264 printf("%s: dst %s thresholds\n", ic->ic_if.if_xname, 265 ether_sprintf((u_int8_t *)ni->ni_macaddr)); 266 for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) { 267 printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << 268 (IEEE80211_RSSADAPT_BKTPOWER * i)); 269 for (j = 0; j < rs->rs_nrates; j++) { 270 rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL); 271 printf(", T[%d.%d] = %d", rate / 2, 272 rate * 5 % 10, ra->ra_rate_thresh[i][j]); 273 } 274 printf("\n"); 275 } 276 } 277 #endif /* IEEE80211_DEBUG */ 278 } 279