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/8.0/sys/net80211/ieee80211_amrr.c 178354 2008-04-20 20:35:46Z 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 "opt_wlan.h"
32
33 #include <sys/param.h>
34 #include <sys/kernel.h>
35 #include <sys/module.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_amrr.h>
49
50 #define is_success(amn) \
51 ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
52 #define is_failure(amn) \
53 ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
54 #define is_enough(amn) \
55 ((amn)->amn_txcnt > 10)
56
57 static void amrr_sysctlattach(struct ieee80211_amrr *amrr,
58 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree);
59
60 /* number of references from net80211 layer */
61 static int nrefs = 0;
62
63 void
64 ieee80211_amrr_setinterval(struct ieee80211_amrr *amrr, int msecs)
65 {
66 int t;
67
68 if (msecs < 100)
69 msecs = 100;
70 t = msecs_to_ticks(msecs);
71 amrr->amrr_interval = (t < 1) ? 1 : t;
72 }
73
74 void
75 ieee80211_amrr_init(struct ieee80211_amrr *amrr,
76 struct ieee80211vap *vap, int amin, int amax, int interval)
77 {
78 /* XXX bounds check? */
79 amrr->amrr_min_success_threshold = amin;
80 amrr->amrr_max_success_threshold = amax;
81 ieee80211_amrr_setinterval(amrr, interval);
82
83 amrr_sysctlattach(amrr, vap->iv_sysctl, vap->iv_oid);
84 }
85
86 void
87 ieee80211_amrr_cleanup(struct ieee80211_amrr *amrr)
88 {
89 }
90
91 void
92 ieee80211_amrr_node_init(struct ieee80211_amrr *amrr,
93 struct ieee80211_amrr_node *amn, struct ieee80211_node *ni)
94 {
95 const struct ieee80211_rateset *rs = &ni->ni_rates;
96
97 amn->amn_amrr = amrr;
98 amn->amn_success = 0;
99 amn->amn_recovery = 0;
100 amn->amn_txcnt = amn->amn_retrycnt = 0;
101 amn->amn_success_threshold = amrr->amrr_min_success_threshold;
102
103 /* pick initial rate */
104 for (amn->amn_rix = rs->rs_nrates - 1;
105 amn->amn_rix > 0 && (rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) > 72;
106 amn->amn_rix--)
107 ;
108 ni->ni_txrate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
109 amn->amn_ticks = ticks;
110
111 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
112 "AMRR initial rate %d", ni->ni_txrate);
113 }
114
115 static int
116 amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
117 struct ieee80211_node *ni)
118 {
119 int rix = amn->amn_rix;
120
121 KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
122
123 if (is_success(amn)) {
124 amn->amn_success++;
125 if (amn->amn_success >= amn->amn_success_threshold &&
126 rix + 1 < ni->ni_rates.rs_nrates) {
127 amn->amn_recovery = 1;
128 amn->amn_success = 0;
129 rix++;
130 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
131 "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
132 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
133 amn->amn_txcnt, amn->amn_retrycnt);
134 } else {
135 amn->amn_recovery = 0;
136 }
137 } else if (is_failure(amn)) {
138 amn->amn_success = 0;
139 if (rix > 0) {
140 if (amn->amn_recovery) {
141 amn->amn_success_threshold *= 2;
142 if (amn->amn_success_threshold >
143 amrr->amrr_max_success_threshold)
144 amn->amn_success_threshold =
145 amrr->amrr_max_success_threshold;
146 } else {
147 amn->amn_success_threshold =
148 amrr->amrr_min_success_threshold;
149 }
150 rix--;
151 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
152 "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
153 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
154 amn->amn_txcnt, amn->amn_retrycnt);
155 }
156 amn->amn_recovery = 0;
157 }
158
159 /* reset counters */
160 amn->amn_txcnt = 0;
161 amn->amn_retrycnt = 0;
162
163 return rix;
164 }
165
166 /*
167 * Return the rate index to use in sending a data frame.
168 * Update our internal state if it's been long enough.
169 * If the rate changes we also update ni_txrate to match.
170 */
171 int
172 ieee80211_amrr_choose(struct ieee80211_node *ni,
173 struct ieee80211_amrr_node *amn)
174 {
175 struct ieee80211_amrr *amrr = amn->amn_amrr;
176 int rix;
177
178 if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
179 rix = amrr_update(amrr, amn, ni);
180 if (rix != amn->amn_rix) {
181 /* update public rate */
182 ni->ni_txrate =
183 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
184 amn->amn_rix = rix;
185 }
186 amn->amn_ticks = ticks;
187 } else
188 rix = amn->amn_rix;
189 return rix;
190 }
191
192 static int
193 amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
194 {
195 struct ieee80211_amrr *amrr = arg1;
196 int msecs = ticks_to_msecs(amrr->amrr_interval);
197 int error;
198
199 error = sysctl_handle_int(oidp, &msecs, 0, req);
200 if (error || !req->newptr)
201 return error;
202 ieee80211_amrr_setinterval(amrr, msecs);
203 return 0;
204 }
205
206 static void
207 amrr_sysctlattach(struct ieee80211_amrr *amrr,
208 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
209 {
210
211 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
212 "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, amrr,
213 0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
214 /* XXX bounds check values */
215 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
216 "amrr_max_sucess_threshold", CTLFLAG_RW,
217 &amrr->amrr_max_success_threshold, 0, "");
218 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
219 "amrr_min_sucess_threshold", CTLFLAG_RW,
220 &amrr->amrr_min_success_threshold, 0, "");
221 }
222
223 /*
224 * Module glue.
225 */
226 IEEE80211_RATE_MODULE(amrr, 1);
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