1 /* $OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $ */ 2 3 /*- 4 * Copyright (c) 2006 5 * Damien Bergamini <damien.bergamini@free.fr> 6 * 7 * Permission to use, copy, modify, and distribute this software for any 8 * purpose with or without fee is hereby granted, provided that the above 9 * copyright notice and this permission notice appear in all copies. 10 * 11 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 12 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 13 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 14 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 15 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 16 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 17 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 18 */ 19 20 #include <sys/cdefs.h> 21 __FBSDID("$FreeBSD$"); 22 23 /*- 24 * Naive implementation of the Adaptive Multi Rate Retry algorithm: 25 * 26 * "IEEE 802.11 Rate Adaptation: A Practical Approach" 27 * Mathieu Lacage, Hossein Manshaei, Thierry Turletti 28 * INRIA Sophia - Projet Planete 29 * http://www-sop.inria.fr/rapports/sophia/RR-5208.html 30 */ 31 #include <sys/param.h> 32 #include <sys/kernel.h> 33 #include <sys/module.h> 34 #include <sys/socket.h> 35 #include <sys/sysctl.h> 36 37 #include <net/if.h> 38 #include <net/if_media.h> 39 40 #ifdef INET 41 #include <netinet/in.h> 42 #include <netinet/if_ether.h> 43 #endif 44 45 #include <net80211/ieee80211.h> 46 #include <net80211/ieee80211_var.h> 47 #include <net80211/ieee80211_amrr.h> 48 49 #define is_success(amn) \ 50 ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10) 51 #define is_failure(amn) \ 52 ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3) 53 #define is_enough(amn) \ 54 ((amn)->amn_txcnt > 10) 55 #define is_min_rate(ni) \ 56 ((ni)->ni_txrate == 0) 57 #define is_max_rate(ni) \ 58 ((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1) 59 #define increase_rate(ni) \ 60 ((ni)->ni_txrate++) 61 #define decrease_rate(ni) \ 62 ((ni)->ni_txrate--) 63 #define reset_cnt(amn) \ 64 do { (amn)->amn_txcnt = (amn)->amn_retrycnt = 0; } while (0) 65 66 void 67 ieee80211_amrr_init(struct ieee80211_amrr *amrr, 68 struct ieee80211com *ic, int min, int max) 69 { 70 /* XXX bounds check? */ 71 amrr->amrr_min_success_threshold = min; 72 amrr->amrr_max_success_threshold = max; 73 amrr->amrr_ic = ic; 74 } 75 76 void 77 ieee80211_amrr_node_init(struct ieee80211_amrr *amrr, 78 struct ieee80211_amrr_node *amn) 79 { 80 amn->amn_success = 0; 81 amn->amn_recovery = 0; 82 amn->amn_txcnt = amn->amn_retrycnt = 0; 83 amn->amn_success_threshold = amrr->amrr_min_success_threshold; 84 } 85 86 /* 87 * Update ni->ni_txrate. 88 */ 89 void 90 ieee80211_amrr_choose(struct ieee80211_amrr *amrr, struct ieee80211_node *ni, 91 struct ieee80211_amrr_node *amn) 92 { 93 int need_change = 0; 94 95 if (is_success(amn) && is_enough(amn)) { 96 amn->amn_success++; 97 if (amn->amn_success >= amn->amn_success_threshold && 98 !is_max_rate(ni)) { 99 amn->amn_recovery = 1; 100 amn->amn_success = 0; 101 increase_rate(ni); 102 IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL, 103 "AMRR increasing rate %d (txcnt=%d " 104 "retrycnt=%d)\n", 105 ni->ni_rates.rs_rates[ni->ni_txrate] & 106 IEEE80211_RATE_VAL, 107 amn->amn_txcnt, amn->amn_retrycnt); 108 need_change = 1; 109 } else { 110 amn->amn_recovery = 0; 111 } 112 } else if (is_failure(amn)) { 113 amn->amn_success = 0; 114 if (!is_min_rate(ni)) { 115 if (amn->amn_recovery) { 116 amn->amn_success_threshold *= 2; 117 if (amn->amn_success_threshold > 118 amrr->amrr_max_success_threshold) 119 amn->amn_success_threshold = 120 amrr->amrr_max_success_threshold; 121 } else { 122 amn->amn_success_threshold = 123 amrr->amrr_min_success_threshold; 124 } 125 decrease_rate(ni); 126 IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL, 127 "AMRR decreasing rate %d (txcnt=%d " 128 "retrycnt=%d)\n", 129 ni->ni_rates.rs_rates[ni->ni_txrate] & 130 IEEE80211_RATE_VAL, 131 amn->amn_txcnt, amn->amn_retrycnt); 132 need_change = 1; 133 } 134 amn->amn_recovery = 0; 135 } 136 137 if (is_enough(amn) || need_change) 138 reset_cnt(amn); 139 } 140 141 /* 142 * Module glue. 143 */ 144 static int 145 amrr_modevent(module_t mod, int type, void *unused) 146 { 147 switch (type) { 148 case MOD_LOAD: 149 if (bootverbose) 150 printf("wlan_amrr: <AMRR Transmit Rate Control Algorithm>\n"); 151 return 0; 152 case MOD_UNLOAD: 153 return 0; 154 } 155 return EINVAL; 156 } 157 158 static moduledata_t amrr_mod = { 159 "wlan_amrr", 160 amrr_modevent, 161 0 162 }; 163 DECLARE_MODULE(wlan_amrr, amrr_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 164 MODULE_VERSION(wlan_amrr, 1); 165