1/* $OpenBSD: ieee80211_amrr.c,v 1.1 2006/06/17 19:07:19 damien Exp $ */
2
3/*-
4 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
5 * Copyright (c) 2006
6 * Damien Bergamini <damien.bergamini@free.fr>
7 *
8 * Permission to use, copy, modify, and distribute this software for any
9 * purpose with or without fee is hereby granted, provided that the above
10 * copyright notice and this permission notice appear in all copies.
11 *
12 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
13 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
14 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
15 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
16 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
17 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
18 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
19 */
20
21#include <sys/cdefs.h>
22__FBSDID("$FreeBSD: head/sys/net80211/ieee80211_amrr.c 207323 2010-04-28 13:25:53Z rpaulo $");
23
24/*-
25 * Naive implementation of the Adaptive Multi Rate Retry algorithm:
26 *
27 * "IEEE 802.11 Rate Adaptation: A Practical Approach"
28 * Mathieu Lacage, Hossein Manshaei, Thierry Turletti
29 * INRIA Sophia - Projet Planete
30 * http://www-sop.inria.fr/rapports/sophia/RR-5208.html
31 */
32#include "opt_wlan.h"
33
34#include <sys/param.h>
35#include <sys/kernel.h>
36#include <sys/module.h>
37#include <sys/socket.h>
38#include <sys/sysctl.h>
39
40#include <net/if.h>
41#include <net/if_media.h>
42
43#ifdef INET
44#include <netinet/in.h>
45#include <netinet/if_ether.h>
46#endif
47
48#include <net80211/ieee80211_var.h>
49#include <net80211/ieee80211_amrr.h>
50#include <net80211/ieee80211_ratectl.h>
51
52#define is_success(amn) \
53 ((amn)->amn_retrycnt < (amn)->amn_txcnt / 10)
54#define is_failure(amn) \
55 ((amn)->amn_retrycnt > (amn)->amn_txcnt / 3)
56#define is_enough(amn) \
57 ((amn)->amn_txcnt > 10)
58
59static void amrr_setinterval(const struct ieee80211vap *, int);
60static void amrr_init(struct ieee80211vap *);
61static void amrr_deinit(struct ieee80211vap *);
62static void amrr_node_init(struct ieee80211_node *);
63static void amrr_node_deinit(struct ieee80211_node *);
64static int amrr_update(struct ieee80211_amrr *,
65 struct ieee80211_amrr_node *, struct ieee80211_node *);
66static int amrr_rate(struct ieee80211_node *, void *, uint32_t);
67static void amrr_tx_complete(const struct ieee80211vap *,
68 const struct ieee80211_node *, int,
69 void *, void *);
70static void amrr_tx_update(const struct ieee80211vap *vap,
71 const struct ieee80211_node *, void *, void *, void *);
72static void amrr_sysctlattach(struct ieee80211vap *,
73 struct sysctl_ctx_list *, struct sysctl_oid *);
74
75/* number of references from net80211 layer */
76static int nrefs = 0;
77
78static const struct ieee80211_ratectl amrr = {
79 .ir_name = "amrr",
80 .ir_attach = NULL,
81 .ir_detach = NULL,
82 .ir_init = amrr_init,
83 .ir_deinit = amrr_deinit,
84 .ir_node_init = amrr_node_init,
85 .ir_node_deinit = amrr_node_deinit,
86 .ir_rate = amrr_rate,
87 .ir_tx_complete = amrr_tx_complete,
88 .ir_tx_update = amrr_tx_update,
89 .ir_setinterval = amrr_setinterval,
90};
91IEEE80211_RATECTL_MODULE(amrr, 1);
92IEEE80211_RATECTL_ALG(amrr, IEEE80211_RATECTL_AMRR, amrr);
93
94static void
95amrr_setinterval(const struct ieee80211vap *vap, int msecs)
96{
97 struct ieee80211_amrr *amrr = vap->iv_rs;
98 int t;
99
100 if (msecs < 100)
101 msecs = 100;
102 t = msecs_to_ticks(msecs);
103 amrr->amrr_interval = (t < 1) ? 1 : t;
104}
105
106static void
107amrr_init(struct ieee80211vap *vap)
108{
109 struct ieee80211_amrr *amrr;
110
111 KASSERT(vap->iv_rs == NULL, ("%s called multiple times", __func__));
112
113 amrr = vap->iv_rs = malloc(sizeof(struct ieee80211_amrr),
114 M_80211_RATECTL, M_NOWAIT|M_ZERO);
115 if (amrr == NULL) {
116 if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
117 return;
118 }
119 amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
120 amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
121 amrr_setinterval(vap, 500 /* ms */);
122 amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
123}
124
125static void
126amrr_deinit(struct ieee80211vap *vap)
127{
128 free(vap->iv_rs, M_80211_RATECTL);
129}
130
131static void
132amrr_node_init(struct ieee80211_node *ni)
133{
134 const struct ieee80211_rateset *rs = &ni->ni_rates;
135 struct ieee80211vap *vap = ni->ni_vap;
136 struct ieee80211_amrr *amrr = vap->iv_rs;
137 struct ieee80211_amrr_node *amn;
138
139 if (ni->ni_rctls == NULL) {
140 ni->ni_rctls = amn = malloc(sizeof(struct ieee80211_amrr_node),
141 M_80211_RATECTL, M_NOWAIT|M_ZERO);
142 if (amn == NULL) {
143 if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
144 "structure\n");
145 return;
146 }
147 } else
148 amn = ni->ni_rctls;
149 amn->amn_amrr = amrr;
150 amn->amn_success = 0;
151 amn->amn_recovery = 0;
152 amn->amn_txcnt = amn->amn_retrycnt = 0;
153 amn->amn_success_threshold = amrr->amrr_min_success_threshold;
154
155 /* pick initial rate */
156 for (amn->amn_rix = rs->rs_nrates - 1;
157 amn->amn_rix > 0 && (rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) > 72;
158 amn->amn_rix--)
159 ;
160 ni->ni_txrate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
161 amn->amn_ticks = ticks;
162
163 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
164 "AMRR initial rate %d", ni->ni_txrate);
165}
166
167static void
168amrr_node_deinit(struct ieee80211_node *ni)
169{
170 free(ni->ni_rctls, M_80211_RATECTL);
171}
172
173static int
174amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
175 struct ieee80211_node *ni)
176{
177 int rix = amn->amn_rix;
178
179 KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
180
181 if (is_success(amn)) {
182 amn->amn_success++;
183 if (amn->amn_success >= amn->amn_success_threshold &&
184 rix + 1 < ni->ni_rates.rs_nrates) {
185 amn->amn_recovery = 1;
186 amn->amn_success = 0;
187 rix++;
188 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
189 "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
190 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
191 amn->amn_txcnt, amn->amn_retrycnt);
192 } else {
193 amn->amn_recovery = 0;
194 }
195 } else if (is_failure(amn)) {
196 amn->amn_success = 0;
197 if (rix > 0) {
198 if (amn->amn_recovery) {
199 amn->amn_success_threshold *= 2;
200 if (amn->amn_success_threshold >
201 amrr->amrr_max_success_threshold)
202 amn->amn_success_threshold =
203 amrr->amrr_max_success_threshold;
204 } else {
205 amn->amn_success_threshold =
206 amrr->amrr_min_success_threshold;
207 }
208 rix--;
209 IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
210 "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
211 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
212 amn->amn_txcnt, amn->amn_retrycnt);
213 }
214 amn->amn_recovery = 0;
215 }
216
217 /* reset counters */
218 amn->amn_txcnt = 0;
219 amn->amn_retrycnt = 0;
220
221 return rix;
222}
223
224/*
225 * Return the rate index to use in sending a data frame.
226 * Update our internal state if it's been long enough.
227 * If the rate changes we also update ni_txrate to match.
228 */
229static int
230amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
231{
232 struct ieee80211_amrr_node *amn = ni->ni_rctls;
233 struct ieee80211_amrr *amrr = amn->amn_amrr;
234 int rix;
235
236 if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
237 rix = amrr_update(amrr, amn, ni);
238 if (rix != amn->amn_rix) {
239 /* update public rate */
240 ni->ni_txrate =
241 ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
242 amn->amn_rix = rix;
243 }
244 amn->amn_ticks = ticks;
245 } else
246 rix = amn->amn_rix;
247 return rix;
248}
249
250/*
251 * Update statistics with tx complete status. Ok is non-zero
252 * if the packet is known to be ACK'd. Retries has the number
253 * retransmissions (i.e. xmit attempts - 1).
254 */
255static void
256amrr_tx_complete(const struct ieee80211vap *vap,
257 const struct ieee80211_node *ni, int ok,
258 void *arg1, void *arg2 __unused)
259{
260 struct ieee80211_amrr_node *amn = ni->ni_rctls;
261 int retries = *(int *)arg1;
262
263 amn->amn_txcnt++;
264 if (ok)
265 amn->amn_success++;
266 amn->amn_retrycnt += retries;
267}
268
269/*
270 * Set tx count/retry statistics explicitly. Intended for
271 * drivers that poll the device for statistics maintained
272 * in the device.
273 */
274static void
275amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
276 void *arg1, void *arg2, void *arg3)
277{
278 struct ieee80211_amrr_node *amn = ni->ni_rctls;
279 int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
280
281 amn->amn_txcnt = txcnt;
282 amn->amn_success = success;
283 amn->amn_retrycnt = retrycnt;
284}
285
286static int
287amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
288{
289 struct ieee80211vap *vap = arg1;
290 struct ieee80211_amrr *amrr = vap->iv_rs;
291 int msecs = ticks_to_msecs(amrr->amrr_interval);
292 int error;
293
294 error = sysctl_handle_int(oidp, &msecs, 0, req);
295 if (error || !req->newptr)
296 return error;
297 amrr_setinterval(vap, msecs);
298 return 0;
299}
300
301static void
302amrr_sysctlattach(struct ieee80211vap *vap,
303 struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
304{
305 struct ieee80211_amrr *amrr = vap->iv_rs;
306
307 SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
308 "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
309 0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
310 /* XXX bounds check values */
311 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
312 "amrr_max_sucess_threshold", CTLFLAG_RW,
313 &amrr->amrr_max_success_threshold, 0, "");
314 SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
315 "amrr_min_sucess_threshold", CTLFLAG_RW,
316 &amrr->amrr_min_success_threshold, 0, "");
317}