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);
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