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: releng/6.4/sys/net80211/ieee80211_amrr.c 166251 2007-01-26 06:40:28Z sam $");
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);
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