1 /* $OpenBSD: ieee80211_rssadapt.c,v 1.4 2005/09/08 13:24:53 reyk 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.h> 49 #include <net80211/ieee80211_rssadapt.h> 50 51 #ifdef interpolate 52 #undef interpolate 53 #endif 54 #define interpolate(parm, old, new) \ 55 ((parm##_old * (old) + \ 56 (parm##_denom - parm##_old) * (new)) / parm##_denom) 57 58 #ifdef IEEE80211_DEBUG 59 static struct timeval lastrateadapt; /* time of last rate adaptation msg */ 60 static int currssadaptps = 0; /* rate-adaptation msgs this second */ 61 static int ieee80211_adaptrate = 4; /* rate-adaptation max msgs/sec */ 62 63 #define RSSADAPT_DO_PRINT() \ 64 ((ieee80211_rssadapt_debug > 0) && \ 65 ppsratecheck(&lastrateadapt, &currssadaptps, ieee80211_adaptrate)) 66 #define RSSADAPT_PRINTF(X) \ 67 if (RSSADAPT_DO_PRINT()) \ 68 printf X 69 70 int ieee80211_rssadapt_debug = 0; 71 72 #else 73 #define RSSADAPT_DO_PRINT() (0) 74 #define RSSADAPT_PRINTF(X) 75 #endif 76 77 static struct ieee80211_rssadapt_expavgctl master_expavgctl = { 78 rc_decay_denom : 16, 79 rc_decay_old : 15, 80 rc_thresh_denom : 8, 81 rc_thresh_old : 4, 82 rc_avgrssi_denom : 8, 83 rc_avgrssi_old : 4 84 }; 85 86 int 87 ieee80211_rssadapt_choose(struct ieee80211_rssadapt *ra, 88 struct ieee80211_rateset *rs, struct ieee80211_frame *wh, u_int len, 89 int fixed_rate, const char *dvname, int do_not_adapt) 90 { 91 u_int16_t (*thrs)[IEEE80211_RATE_SIZE]; 92 int flags = 0, i, rateidx = 0, thridx, top; 93 94 if ((wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_CTL) 95 flags |= IEEE80211_RATE_BASIC; 96 97 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 98 i < IEEE80211_RSSADAPT_BKTS; 99 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 100 thridx = i; 101 if (len <= top) 102 break; 103 } 104 105 thrs = &ra->ra_rate_thresh[thridx]; 106 107 if (fixed_rate != -1) { 108 if ((rs->rs_rates[fixed_rate] & flags) == flags) { 109 rateidx = fixed_rate; 110 goto out; 111 } 112 flags |= IEEE80211_RATE_BASIC; 113 i = fixed_rate; 114 } else 115 i = rs->rs_nrates; 116 117 while (--i >= 0) { 118 rateidx = i; 119 if ((rs->rs_rates[i] & flags) != flags) 120 continue; 121 if (do_not_adapt) 122 break; 123 if ((*thrs)[i] < ra->ra_avg_rssi) 124 break; 125 } 126 127 out: 128 #ifdef IEEE80211_DEBUG 129 if (ieee80211_rssadapt_debug && dvname != NULL) { 130 printf("%s: dst %s threshold[%d, %d.%d] %d < %d\n", 131 dvname, ether_sprintf(wh->i_addr1), len, 132 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) / 2, 133 (rs->rs_rates[rateidx] & IEEE80211_RATE_VAL) * 5 % 10, 134 (*thrs)[rateidx], ra->ra_avg_rssi); 135 } 136 #endif /* IEEE80211_DEBUG */ 137 return rateidx; 138 } 139 140 void 141 ieee80211_rssadapt_updatestats(struct ieee80211_rssadapt *ra) 142 { 143 long interval; 144 145 ra->ra_pktrate = 146 (ra->ra_pktrate + 10 * (ra->ra_nfail + ra->ra_nok)) / 2; 147 ra->ra_nfail = ra->ra_nok = 0; 148 149 /* a node is eligible for its rate to be raised every 1/10 to 10 150 * seconds, more eligible in proportion to recent packet rates. 151 */ 152 interval = MAX(100000, 10000000 / MAX(1, 10 * ra->ra_pktrate)); 153 ra->ra_raise_interval.tv_sec = interval / (1000 * 1000); 154 ra->ra_raise_interval.tv_usec = interval % (1000 * 1000); 155 } 156 157 void 158 ieee80211_rssadapt_input(struct ieee80211com *ic, struct ieee80211_node *ni, 159 struct ieee80211_rssadapt *ra, int rssi) 160 { 161 #ifdef IEEE80211_DEBUG 162 int last_avg_rssi = ra->ra_avg_rssi; 163 #endif 164 165 ra->ra_avg_rssi = interpolate(master_expavgctl.rc_avgrssi, 166 ra->ra_avg_rssi, (rssi << 8)); 167 168 RSSADAPT_PRINTF(("%s: src %s rssi %d avg %d -> %d\n", 169 ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr), 170 rssi, last_avg_rssi, ra->ra_avg_rssi)); 171 } 172 173 /* 174 * Adapt the data rate to suit the conditions. When a transmitted 175 * packet is dropped after IEEE80211_RSSADAPT_RETRY_LIMIT retransmissions, 176 * raise the RSS threshold for transmitting packets of similar length at 177 * the same data rate. 178 */ 179 void 180 ieee80211_rssadapt_lower_rate(struct ieee80211com *ic, 181 struct ieee80211_node *ni, struct ieee80211_rssadapt *ra, 182 struct ieee80211_rssdesc *id) 183 { 184 struct ieee80211_rateset *rs = &ni->ni_rates; 185 u_int16_t last_thr; 186 u_int i, thridx, top; 187 188 ra->ra_nfail++; 189 190 if (id->id_rateidx >= rs->rs_nrates) { 191 RSSADAPT_PRINTF(("ieee80211_rssadapt_lower_rate: " 192 "%s rate #%d > #%d out of bounds\n", 193 ether_sprintf(ni->ni_macaddr), id->id_rateidx, 194 rs->rs_nrates - 1)); 195 return; 196 } 197 198 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 199 i < IEEE80211_RSSADAPT_BKTS; 200 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 201 thridx = i; 202 if (id->id_len <= top) 203 break; 204 } 205 206 last_thr = ra->ra_rate_thresh[thridx][id->id_rateidx]; 207 ra->ra_rate_thresh[thridx][id->id_rateidx] = 208 interpolate(master_expavgctl.rc_thresh, last_thr, 209 (id->id_rssi << 8)); 210 211 RSSADAPT_PRINTF(("%s: dst %s rssi %d threshold[%d, %d.%d] %d -> %d\n", 212 ic->ic_if.if_xname, ether_sprintf(ni->ni_macaddr), 213 id->id_rssi, id->id_len, 214 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) / 2, 215 (rs->rs_rates[id->id_rateidx] & IEEE80211_RATE_VAL) * 5 % 10, 216 last_thr, ra->ra_rate_thresh[thridx][id->id_rateidx])); 217 } 218 219 void 220 ieee80211_rssadapt_raise_rate(struct ieee80211com *ic, 221 struct ieee80211_rssadapt *ra, struct ieee80211_rssdesc *id) 222 { 223 u_int16_t (*thrs)[IEEE80211_RATE_SIZE], newthr, oldthr; 224 struct ieee80211_node *ni = id->id_node; 225 struct ieee80211_rateset *rs = &ni->ni_rates; 226 int i, rate, top; 227 #ifdef IEEE80211_DEBUG 228 int j; 229 #endif 230 231 ra->ra_nok++; 232 233 if (!ratecheck(&ra->ra_last_raise, &ra->ra_raise_interval)) 234 return; 235 236 for (i = 0, top = IEEE80211_RSSADAPT_BKT0; 237 i < IEEE80211_RSSADAPT_BKTS; 238 i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) { 239 thrs = &ra->ra_rate_thresh[i]; 240 if (id->id_len <= top) 241 break; 242 } 243 244 if (id->id_rateidx + 1 < rs->rs_nrates && 245 (*thrs)[id->id_rateidx + 1] > (*thrs)[id->id_rateidx]) { 246 rate = (rs->rs_rates[id->id_rateidx + 1] & IEEE80211_RATE_VAL); 247 248 RSSADAPT_PRINTF(("%s: threshold[%d, %d.%d] decay %d ", 249 ic->ic_if.if_xname, 250 IEEE80211_RSSADAPT_BKT0 << (IEEE80211_RSSADAPT_BKTPOWER* i), 251 rate / 2, rate * 5 % 10, (*thrs)[id->id_rateidx + 1])); 252 oldthr = (*thrs)[id->id_rateidx + 1]; 253 if ((*thrs)[id->id_rateidx] == 0) 254 newthr = ra->ra_avg_rssi; 255 else 256 newthr = (*thrs)[id->id_rateidx]; 257 (*thrs)[id->id_rateidx + 1] = 258 interpolate(master_expavgctl.rc_decay, oldthr, newthr); 259 260 RSSADAPT_PRINTF(("-> %d\n", (*thrs)[id->id_rateidx + 1])); 261 } 262 263 #ifdef IEEE80211_DEBUG 264 if (RSSADAPT_DO_PRINT()) { 265 printf("%s: dst %s thresholds\n", ic->ic_if.if_xname, 266 ether_sprintf(ni->ni_macaddr)); 267 for (i = 0; i < IEEE80211_RSSADAPT_BKTS; i++) { 268 printf("%d-byte", IEEE80211_RSSADAPT_BKT0 << 269 (IEEE80211_RSSADAPT_BKTPOWER * i)); 270 for (j = 0; j < rs->rs_nrates; j++) { 271 rate = (rs->rs_rates[j] & IEEE80211_RATE_VAL); 272 printf(", T[%d.%d] = %d", rate / 2, 273 rate * 5 % 10, ra->ra_rate_thresh[i][j]); 274 } 275 printf("\n"); 276 } 277 } 278 #endif /* IEEE80211_DEBUG */ 279 } 280