ieee80211_amrr.c revision 206358 
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 206358 2010-04-07 15:29:13Z 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	vap->iv_rs = malloc(sizeof(struct ieee80211_amrr), M_80211_RATECTL,
114	    M_WAITOK|M_ZERO);
115	amrr = vap->iv_rs;
116	amrr->amrr_min_success_threshold = IEEE80211_AMRR_MIN_SUCCESS_THRESHOLD;
117	amrr->amrr_max_success_threshold = IEEE80211_AMRR_MAX_SUCCESS_THRESHOLD;
118	amrr_setinterval(vap, 500 /* ms */);
119	amrr_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
120}
121
122static void
123amrr_deinit(struct ieee80211vap *vap)
124{
125	free(vap->iv_rs, M_80211_RATECTL);
126}
127
128static void
129amrr_node_init(struct ieee80211_node *ni)
130{
131	const struct ieee80211_rateset *rs = &ni->ni_rates;
132	struct ieee80211vap *vap = ni->ni_vap;
133	struct ieee80211_amrr *amrr = vap->iv_rs;
134	struct ieee80211_amrr_node *amn;
135
136	KASSERT(ni->ni_rctls == NULL, ("%s: ni_rctls already initialized",
137	    __func__));
138
139	ni->ni_rctls = malloc(sizeof(struct ieee80211_amrr_node),
140	    M_80211_RATECTL, M_WAITOK|M_ZERO);
141	amn = ni->ni_rctls;
142	amn->amn_amrr = amrr;
143	amn->amn_success = 0;
144	amn->amn_recovery = 0;
145	amn->amn_txcnt = amn->amn_retrycnt = 0;
146	amn->amn_success_threshold = amrr->amrr_min_success_threshold;
147
148	/* pick initial rate */
149	for (amn->amn_rix = rs->rs_nrates - 1;
150	     amn->amn_rix > 0 && (rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL) > 72;
151	     amn->amn_rix--)
152		;
153	ni->ni_txrate = rs->rs_rates[amn->amn_rix] & IEEE80211_RATE_VAL;
154	amn->amn_ticks = ticks;
155
156	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
157	    "AMRR initial rate %d", ni->ni_txrate);
158}
159
160static void
161amrr_node_deinit(struct ieee80211_node *ni)
162{
163	free(ni->ni_rctls, M_80211_RATECTL);
164}
165
166static int
167amrr_update(struct ieee80211_amrr *amrr, struct ieee80211_amrr_node *amn,
168    struct ieee80211_node *ni)
169{
170	int rix = amn->amn_rix;
171
172	KASSERT(is_enough(amn), ("txcnt %d", amn->amn_txcnt));
173
174	if (is_success(amn)) {
175		amn->amn_success++;
176		if (amn->amn_success >= amn->amn_success_threshold &&
177		    rix + 1 < ni->ni_rates.rs_nrates) {
178			amn->amn_recovery = 1;
179			amn->amn_success = 0;
180			rix++;
181			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
182			    "AMRR increasing rate %d (txcnt=%d retrycnt=%d)",
183			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
184			    amn->amn_txcnt, amn->amn_retrycnt);
185		} else {
186			amn->amn_recovery = 0;
187		}
188	} else if (is_failure(amn)) {
189		amn->amn_success = 0;
190		if (rix > 0) {
191			if (amn->amn_recovery) {
192				amn->amn_success_threshold *= 2;
193				if (amn->amn_success_threshold >
194				    amrr->amrr_max_success_threshold)
195					amn->amn_success_threshold =
196					    amrr->amrr_max_success_threshold;
197			} else {
198				amn->amn_success_threshold =
199				    amrr->amrr_min_success_threshold;
200			}
201			rix--;
202			IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
203			    "AMRR decreasing rate %d (txcnt=%d retrycnt=%d)",
204			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL,
205			    amn->amn_txcnt, amn->amn_retrycnt);
206		}
207		amn->amn_recovery = 0;
208	}
209
210	/* reset counters */
211	amn->amn_txcnt = 0;
212	amn->amn_retrycnt = 0;
213
214	return rix;
215}
216
217/*
218 * Return the rate index to use in sending a data frame.
219 * Update our internal state if it's been long enough.
220 * If the rate changes we also update ni_txrate to match.
221 */
222static int
223amrr_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg __unused)
224{
225	struct ieee80211_amrr_node *amn = ni->ni_rctls;
226	struct ieee80211_amrr *amrr = amn->amn_amrr;
227	int rix;
228
229	if (is_enough(amn) && (ticks - amn->amn_ticks) > amrr->amrr_interval) {
230		rix = amrr_update(amrr, amn, ni);
231		if (rix != amn->amn_rix) {
232			/* update public rate */
233			ni->ni_txrate =
234			    ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
235			amn->amn_rix = rix;
236		}
237		amn->amn_ticks = ticks;
238	} else
239		rix = amn->amn_rix;
240	return rix;
241}
242
243/*
244 * Update statistics with tx complete status.  Ok is non-zero
245 * if the packet is known to be ACK'd.  Retries has the number
246 * retransmissions (i.e. xmit attempts - 1).
247 */
248static void
249amrr_tx_complete(const struct ieee80211vap *vap,
250    const struct ieee80211_node *ni, int ok,
251    void *arg1, void *arg2 __unused)
252{
253	struct ieee80211_amrr_node *amn = ni->ni_rctls;
254	int retries = *(int *)arg1;
255
256	amn->amn_txcnt++;
257	if (ok)
258		amn->amn_success++;
259	amn->amn_retrycnt += retries;
260}
261
262/*
263 * Set tx count/retry statistics explicitly.  Intended for
264 * drivers that poll the device for statistics maintained
265 * in the device.
266 */
267static void
268amrr_tx_update(const struct ieee80211vap *vap, const struct ieee80211_node *ni,
269    void *arg1, void *arg2, void *arg3)
270{
271	struct ieee80211_amrr_node *amn = ni->ni_rctls;
272	int txcnt = *(int *)arg1, success = *(int *)arg2, retrycnt = *(int *)arg3;
273
274	amn->amn_txcnt = txcnt;
275	amn->amn_success = success;
276	amn->amn_retrycnt = retrycnt;
277}
278
279static int
280amrr_sysctl_interval(SYSCTL_HANDLER_ARGS)
281{
282	struct ieee80211vap *vap = arg1;
283	struct ieee80211_amrr *amrr = vap->iv_rs;
284	int msecs = ticks_to_msecs(amrr->amrr_interval);
285	int error;
286
287	error = sysctl_handle_int(oidp, &msecs, 0, req);
288	if (error || !req->newptr)
289		return error;
290	amrr_setinterval(vap, msecs);
291	return 0;
292}
293
294static void
295amrr_sysctlattach(struct ieee80211vap *vap,
296    struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
297{
298	struct ieee80211_amrr *amrr = vap->iv_rs;
299
300	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
301	    "amrr_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
302	    0, amrr_sysctl_interval, "I", "amrr operation interval (ms)");
303	/* XXX bounds check values */
304	SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
305	    "amrr_max_sucess_threshold", CTLFLAG_RW,
306	    &amrr->amrr_max_success_threshold, 0, "");
307	SYSCTL_ADD_INT(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
308	    "amrr_min_sucess_threshold", CTLFLAG_RW,
309	    &amrr->amrr_min_success_threshold, 0, "");
310}
311