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_var.h> 46 #include <net80211/ieee80211_amrr.h> 47 48 #define is_success(amn) \ 49 ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10) 50 #define is_failure(amn) \ 51 ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3) 52 #define is_enough(amn) \ 53 ((amn)->amn_txcnt > 10) 54 #define is_min_rate(ni) \ 55 ((ni)->ni_txrate == 0) 56 #define is_max_rate(ni) \ 57 ((ni)->ni_txrate == (ni)->ni_rates.rs_nrates - 1) 58 #define increase_rate(ni) \ 59 ((ni)->ni_txrate++) 60 #define decrease_rate(ni) \ 61 ((ni)->ni_txrate--) 62 #define reset_cnt(amn) \ 63 do { (amn)->amn_txcnt = (amn)->amn_retrycnt = 0; } while (0) 64 65 void 66 ieee80211_amrr_init(struct ieee80211_amrr *amrr, 67 struct ieee80211com *ic, int amin, int amax) 68 { 69 /* XXX bounds check? */ 70 amrr->amrr_min_success_threshold = amin; 71 amrr->amrr_max_success_threshold = amax; 72 amrr->amrr_ic = ic; 73 } 74 75 void 76 ieee80211_amrr_node_init(struct ieee80211_amrr *amrr, 77 struct ieee80211_amrr_node *amn) 78 { 79 amn->amn_success = 0; 80 amn->amn_recovery = 0; 81 amn->amn_txcnt = amn->amn_retrycnt = 0; 82 amn->amn_success_threshold = amrr->amrr_min_success_threshold; 83 } 84 85 /* 86 * Update ni->ni_txrate. 87 */ 88 void 89 ieee80211_amrr_choose(struct ieee80211_amrr *amrr, struct ieee80211_node *ni, 90 struct ieee80211_amrr_node *amn) 91 { 92 int need_change = 0; 93 94 if (is_success(amn) && is_enough(amn)) { 95 amn->amn_success++; 96 if (amn->amn_success >= amn->amn_success_threshold && 97 !is_max_rate(ni)) { 98 amn->amn_recovery = 1; 99 amn->amn_success = 0; 100 increase_rate(ni); 101 IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL, 102 "AMRR increasing rate %d (txcnt=%d " 103 "retrycnt=%d)\n", 104 ni->ni_rates.rs_rates[ni->ni_txrate] & 105 IEEE80211_RATE_VAL, 106 amn->amn_txcnt, amn->amn_retrycnt); 107 need_change = 1; 108 } else { 109 amn->amn_recovery = 0; 110 } 111 } else if (is_failure(amn)) { 112 amn->amn_success = 0; 113 if (!is_min_rate(ni)) { 114 if (amn->amn_recovery) { 115 amn->amn_success_threshold *= 2; 116 if (amn->amn_success_threshold > 117 amrr->amrr_max_success_threshold) 118 amn->amn_success_threshold = 119 amrr->amrr_max_success_threshold; 120 } else { 121 amn->amn_success_threshold = 122 amrr->amrr_min_success_threshold; 123 } 124 decrease_rate(ni); 125 IEEE80211_DPRINTF(amrr->amrr_ic, IEEE80211_MSG_RATECTL, 126 "AMRR decreasing rate %d (txcnt=%d " 127 "retrycnt=%d)\n", 128 ni->ni_rates.rs_rates[ni->ni_txrate] & 129 IEEE80211_RATE_VAL, 130 amn->amn_txcnt, amn->amn_retrycnt); 131 need_change = 1; 132 } 133 amn->amn_recovery = 0; 134 } 135 136 if (is_enough(amn) || need_change) 137 reset_cnt(amn); 138 } 139 140 /* 141 * Module glue. 142 */ 143 static int 144 amrr_modevent(module_t mod, int type, void *unused) 145 { 146 switch (type) { 147 case MOD_LOAD: 148 if (bootverbose) 149 printf("wlan_amrr: <AMRR Transmit Rate Control Algorithm>\n"); 150 return 0; 151 case MOD_UNLOAD: 152 return 0; 153 } 154 return EINVAL; 155 } 156 157 static moduledata_t amrr_mod = { 158 "wlan_amrr", 159 amrr_modevent, 160 0 161 }; 162 DECLARE_MODULE(wlan_amrr, amrr_mod, SI_SUB_DRIVERS, SI_ORDER_FIRST); 163 MODULE_VERSION(wlan_amrr, 1); 164 MODULE_DEPEND(wlan_amrr, wlan, 1, 1, 1); 165