ieee80211_rssadapt.c revision 283538 
1/*	$FreeBSD: head/sys/net80211/ieee80211_rssadapt.c 283538 2015-05-25 19:18:16Z adrian $	*/
2/* $NetBSD: ieee80211_rssadapt.c,v 1.9 2005/02/26 22:45:09 perry Exp $ */
3/*-
4 * Copyright (c) 2010 Rui Paulo <rpaulo@FreeBSD.org>
5 * Copyright (c) 2003, 2004 David Young.  All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or
8 * without modification, are permitted provided that the following
9 * conditions are met:
10 * 1. Redistributions of source code must retain the above copyright
11 *    notice, this list of conditions and the following disclaimer.
12 * 2. Redistributions in binary form must reproduce the above
13 *    copyright notice, this list of conditions and the following
14 *    disclaimer in the documentation and/or other materials provided
15 *    with the distribution.
16 * 3. The name of David Young may not be used to endorse or promote
17 *    products derived from this software without specific prior
18 *    written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY David Young ``AS IS'' AND ANY
21 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
22 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
23 * PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL David
24 * Young BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
25 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
26 * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
28 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY
31 * OF SUCH DAMAGE.
32 */
33#include "opt_wlan.h"
34
35#include <sys/param.h>
36#include <sys/systm.h>
37#include <sys/kernel.h>
38#include <sys/malloc.h>
39#include <sys/module.h>
40#include <sys/socket.h>
41#include <sys/sysctl.h>
42
43#include <net/if.h>
44#include <net/if_var.h>
45#include <net/if_media.h>
46#include <net/ethernet.h>
47
48#include <net80211/ieee80211_var.h>
49#include <net80211/ieee80211_rssadapt.h>
50#include <net80211/ieee80211_ratectl.h>
51
52struct rssadapt_expavgctl {
53	/* RSS threshold decay. */
54	u_int rc_decay_denom;
55	u_int rc_decay_old;
56	/* RSS threshold update. */
57	u_int rc_thresh_denom;
58	u_int rc_thresh_old;
59	/* RSS average update. */
60	u_int rc_avgrssi_denom;
61	u_int rc_avgrssi_old;
62};
63
64static struct rssadapt_expavgctl master_expavgctl = {
65	.rc_decay_denom = 16,
66	.rc_decay_old = 15,
67	.rc_thresh_denom = 8,
68	.rc_thresh_old = 4,
69	.rc_avgrssi_denom = 8,
70	.rc_avgrssi_old = 4
71};
72
73#ifdef interpolate
74#undef interpolate
75#endif
76#define interpolate(parm, old, new) ((parm##_old * (old) + \
77                                     (parm##_denom - parm##_old) * (new)) / \
78				    parm##_denom)
79
80static void	rssadapt_setinterval(const struct ieee80211vap *, int);
81static void	rssadapt_init(struct ieee80211vap *);
82static void	rssadapt_deinit(struct ieee80211vap *);
83static void	rssadapt_updatestats(struct ieee80211_rssadapt_node *);
84static void	rssadapt_node_init(struct ieee80211_node *);
85static void	rssadapt_node_deinit(struct ieee80211_node *);
86static int	rssadapt_rate(struct ieee80211_node *, void *, uint32_t);
87static void	rssadapt_lower_rate(struct ieee80211_rssadapt_node *, int, int);
88static void	rssadapt_raise_rate(struct ieee80211_rssadapt_node *,
89			int, int);
90static void	rssadapt_tx_complete(const struct ieee80211vap *,
91    			const struct ieee80211_node *, int,
92			void *, void *);
93static void	rssadapt_sysctlattach(struct ieee80211vap *,
94			struct sysctl_ctx_list *, struct sysctl_oid *);
95
96/* number of references from net80211 layer */
97static	int nrefs = 0;
98
99static const struct ieee80211_ratectl rssadapt = {
100	.ir_name	= "rssadapt",
101	.ir_attach	= NULL,
102	.ir_detach	= NULL,
103	.ir_init	= rssadapt_init,
104	.ir_deinit	= rssadapt_deinit,
105	.ir_node_init	= rssadapt_node_init,
106	.ir_node_deinit	= rssadapt_node_deinit,
107	.ir_rate	= rssadapt_rate,
108	.ir_tx_complete	= rssadapt_tx_complete,
109	.ir_tx_update	= NULL,
110	.ir_setinterval	= rssadapt_setinterval,
111};
112IEEE80211_RATECTL_MODULE(rssadapt, 1);
113IEEE80211_RATECTL_ALG(rssadapt, IEEE80211_RATECTL_RSSADAPT, rssadapt);
114
115static void
116rssadapt_setinterval(const struct ieee80211vap *vap, int msecs)
117{
118	struct ieee80211_rssadapt *rs = vap->iv_rs;
119	int t;
120
121	if (msecs < 100)
122		msecs = 100;
123	t = msecs_to_ticks(msecs);
124	rs->interval = (t < 1) ? 1 : t;
125}
126
127static void
128rssadapt_init(struct ieee80211vap *vap)
129{
130	struct ieee80211_rssadapt *rs;
131
132	KASSERT(vap->iv_rs == NULL, ("%s: iv_rs already initialized",
133	    __func__));
134
135	vap->iv_rs = rs = IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt),
136	    M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
137	if (rs == NULL) {
138		if_printf(vap->iv_ifp, "couldn't alloc ratectl structure\n");
139		return;
140	}
141	rs->vap = vap;
142	rssadapt_setinterval(vap, 500 /* msecs */);
143	rssadapt_sysctlattach(vap, vap->iv_sysctl, vap->iv_oid);
144}
145
146static void
147rssadapt_deinit(struct ieee80211vap *vap)
148{
149	IEEE80211_FREE(vap->iv_rs, M_80211_RATECTL);
150}
151
152static void
153rssadapt_updatestats(struct ieee80211_rssadapt_node *ra)
154{
155	long interval;
156
157	ra->ra_pktrate = (ra->ra_pktrate + 10*(ra->ra_nfail + ra->ra_nok))/2;
158	ra->ra_nfail = ra->ra_nok = 0;
159
160	/*
161	 * A node is eligible for its rate to be raised every 1/10 to 10
162	 * seconds, more eligible in proportion to recent packet rates.
163	 */
164	interval = MAX(10*1000, 10*1000 / MAX(1, 10 * ra->ra_pktrate));
165	ra->ra_raise_interval = msecs_to_ticks(interval);
166}
167
168static void
169rssadapt_node_init(struct ieee80211_node *ni)
170{
171	struct ieee80211_rssadapt_node *ra;
172	struct ieee80211vap *vap = ni->ni_vap;
173	struct ieee80211_rssadapt *rsa = vap->iv_rs;
174	const struct ieee80211_rateset *rs = &ni->ni_rates;
175
176	if (ni->ni_rctls == NULL) {
177		ni->ni_rctls = ra =
178		    IEEE80211_MALLOC(sizeof(struct ieee80211_rssadapt_node),
179		        M_80211_RATECTL, IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
180		if (ra == NULL) {
181			if_printf(vap->iv_ifp, "couldn't alloc per-node ratectl "
182			    "structure\n");
183			return;
184		}
185	} else
186		ra = ni->ni_rctls;
187	ra->ra_rs = rsa;
188	ra->ra_rates = *rs;
189	rssadapt_updatestats(ra);
190
191	/* pick initial rate */
192	for (ra->ra_rix = rs->rs_nrates - 1;
193	     ra->ra_rix > 0 && (rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL) > 72;
194	     ra->ra_rix--)
195		;
196	ni->ni_txrate = rs->rs_rates[ra->ra_rix] & IEEE80211_RATE_VAL;
197	ra->ra_ticks = ticks;
198
199	IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
200	    "RSSADAPT initial rate %d", ni->ni_txrate);
201}
202
203static void
204rssadapt_node_deinit(struct ieee80211_node *ni)
205{
206
207	IEEE80211_FREE(ni->ni_rctls, M_80211_RATECTL);
208}
209
210static __inline int
211bucket(int pktlen)
212{
213	int i, top, thridx;
214
215	for (i = 0, top = IEEE80211_RSSADAPT_BKT0;
216	     i < IEEE80211_RSSADAPT_BKTS;
217	     i++, top <<= IEEE80211_RSSADAPT_BKTPOWER) {
218		thridx = i;
219		if (pktlen <= top)
220			break;
221	}
222	return thridx;
223}
224
225static int
226rssadapt_rate(struct ieee80211_node *ni, void *arg __unused, uint32_t iarg)
227{
228	struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
229	u_int pktlen = iarg;
230	const struct ieee80211_rateset *rs = &ra->ra_rates;
231	uint16_t (*thrs)[IEEE80211_RATE_SIZE];
232	int rix, rssi;
233
234	if ((ticks - ra->ra_ticks) > ra->ra_rs->interval) {
235		rssadapt_updatestats(ra);
236		ra->ra_ticks = ticks;
237	}
238
239	thrs = &ra->ra_rate_thresh[bucket(pktlen)];
240
241	/* XXX this is average rssi, should be using last value */
242	rssi = ni->ni_ic->ic_node_getrssi(ni);
243	for (rix = rs->rs_nrates-1; rix >= 0; rix--)
244		if ((*thrs)[rix] < (rssi << 8))
245			break;
246	if (rix != ra->ra_rix) {
247		/* update public rate */
248		ni->ni_txrate = ni->ni_rates.rs_rates[rix] & IEEE80211_RATE_VAL;
249		ra->ra_rix = rix;
250
251		IEEE80211_NOTE(ni->ni_vap, IEEE80211_MSG_RATECTL, ni,
252		    "RSSADAPT new rate %d (pktlen %d rssi %d)",
253		    ni->ni_txrate, pktlen, rssi);
254	}
255	return rix;
256}
257
258/*
259 * Adapt the data rate to suit the conditions.  When a transmitted
260 * packet is dropped after RAL_RSSADAPT_RETRY_LIMIT retransmissions,
261 * raise the RSS threshold for transmitting packets of similar length at
262 * the same data rate.
263 */
264static void
265rssadapt_lower_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
266{
267	uint16_t last_thr;
268	uint16_t (*thrs)[IEEE80211_RATE_SIZE];
269	u_int rix;
270
271	thrs = &ra->ra_rate_thresh[bucket(pktlen)];
272
273	rix = ra->ra_rix;
274	last_thr = (*thrs)[rix];
275	(*thrs)[rix] = interpolate(master_expavgctl.rc_thresh,
276	    last_thr, (rssi << 8));
277
278	IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
279	    "RSSADAPT lower threshold for rate %d (last_thr %d new thr %d rssi %d)\n",
280	    ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
281	    last_thr, (*thrs)[rix], rssi);
282}
283
284static void
285rssadapt_raise_rate(struct ieee80211_rssadapt_node *ra, int pktlen, int rssi)
286{
287	uint16_t (*thrs)[IEEE80211_RATE_SIZE];
288	uint16_t newthr, oldthr;
289	int rix;
290
291	thrs = &ra->ra_rate_thresh[bucket(pktlen)];
292
293	rix = ra->ra_rix;
294	if ((*thrs)[rix + 1] > (*thrs)[rix]) {
295		oldthr = (*thrs)[rix + 1];
296		if ((*thrs)[rix] == 0)
297			newthr = (rssi << 8);
298		else
299			newthr = (*thrs)[rix];
300		(*thrs)[rix + 1] = interpolate(master_expavgctl.rc_decay,
301		    oldthr, newthr);
302
303		IEEE80211_DPRINTF(ra->ra_rs->vap, IEEE80211_MSG_RATECTL,
304		    "RSSADAPT raise threshold for rate %d (oldthr %d newthr %d rssi %d)\n",
305		    ra->ra_rates.rs_rates[rix + 1] & IEEE80211_RATE_VAL,
306		    oldthr, newthr, rssi);
307
308		ra->ra_last_raise = ticks;
309	}
310}
311
312static void
313rssadapt_tx_complete(const struct ieee80211vap *vap,
314    const struct ieee80211_node *ni, int success, void *arg1, void *arg2)
315{
316	struct ieee80211_rssadapt_node *ra = ni->ni_rctls;
317	int pktlen = *(int *)arg1, rssi = *(int *)arg2;
318
319	if (success) {
320		ra->ra_nok++;
321		if ((ra->ra_rix + 1) < ra->ra_rates.rs_nrates &&
322		    (ticks - ra->ra_last_raise) >= ra->ra_raise_interval)
323			rssadapt_raise_rate(ra, pktlen, rssi);
324	} else {
325		ra->ra_nfail++;
326		rssadapt_lower_rate(ra, pktlen, rssi);
327	}
328}
329
330static int
331rssadapt_sysctl_interval(SYSCTL_HANDLER_ARGS)
332{
333	struct ieee80211vap *vap = arg1;
334	struct ieee80211_rssadapt *rs = vap->iv_rs;
335	int msecs = ticks_to_msecs(rs->interval);
336	int error;
337
338	error = sysctl_handle_int(oidp, &msecs, 0, req);
339	if (error || !req->newptr)
340		return error;
341	rssadapt_setinterval(vap, msecs);
342	return 0;
343}
344
345static void
346rssadapt_sysctlattach(struct ieee80211vap *vap,
347    struct sysctl_ctx_list *ctx, struct sysctl_oid *tree)
348{
349
350	SYSCTL_ADD_PROC(ctx, SYSCTL_CHILDREN(tree), OID_AUTO,
351	    "rssadapt_rate_interval", CTLTYPE_INT | CTLFLAG_RW, vap,
352	    0, rssadapt_sysctl_interval, "I", "rssadapt operation interval (ms)");
353}
354