summaryrefslogtreecommitdiffstats
path: root/target/linux/package/ieee80211-dscape/src/rate_control.c
blob: 8782a756da7cf39b12c2da1b43d6703ec27e91c3 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
/*
 * Copyright 2002-2005, Instant802 Networks, Inc.
 * Copyright 2005, Devicescape Software, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/config.h>
#include <linux/version.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/netdevice.h>
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <linux/compiler.h>

#include <net/ieee80211.h>
#include "ieee80211_i.h"
#include "rate_control.h"


/* This is a minimal implementation of TX rate controlling that can be used
 * as the default when no improved mechanisms are available. */


#define RATE_CONTROL_EMERG_DEC 2
#define RATE_CONTROL_INTERVAL (HZ / 20)
#define RATE_CONTROL_MIN_TX 10


static void rate_control_rate_inc(struct ieee80211_local *local,
				  struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata;
	int i = sta->txrate;
	int maxrate;

        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
	if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
		/* forced unicast rate - do not change STA rate */
		return;
	}

	maxrate = sdata->bss ? sdata->bss->max_ratectrl_rateidx : -1;

	if (i > local->num_curr_rates)
		i = local->num_curr_rates - 2;

	while (i + 1 < local->num_curr_rates) {
		i++;
		if (sta->supp_rates & BIT(i) &&
		    local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED &&
		    (maxrate < 0 || i <= maxrate)) {
			sta->txrate = i;
			break;
		}
	}
}


static void rate_control_rate_dec(struct ieee80211_local *local,
				  struct sta_info *sta)
{
        struct ieee80211_sub_if_data *sdata;
	int i = sta->txrate;

        sdata = IEEE80211_DEV_TO_SUB_IF(sta->dev);
	if (sdata->bss && sdata->bss->force_unicast_rateidx > -1) {
		/* forced unicast rate - do not change STA rate */
		return;
	}

	if (i > local->num_curr_rates)
		i = local->num_curr_rates;

	while (i > 0) {
		i--;
		if (sta->supp_rates & BIT(i) &&
		    local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED) {
			sta->txrate = i;
			break;
		}
	}
}


static struct ieee80211_rate *
rate_control_lowest_rate(struct ieee80211_local *local)
{
	int i;

	for (i = 0; i < local->num_curr_rates; i++) {
		struct ieee80211_rate *rate = &local->curr_rates[i];

		if (rate->flags & IEEE80211_RATE_SUPPORTED
			)
			return rate;
	}

	printk(KERN_DEBUG "rate_control_lowest_rate - no supported rates "
	       "found\n");
	return &local->curr_rates[0];
}


struct global_rate_control {
	int dummy;
};

struct sta_rate_control {
        unsigned long last_rate_change;
        u32 tx_num_failures;
        u32 tx_num_xmit;

        unsigned long avg_rate_update;
        u32 tx_avg_rate_sum;
        u32 tx_avg_rate_num;
};


static void rate_control_simple_tx_status(struct net_device *dev,
					  struct sk_buff *skb,
					  struct ieee80211_tx_status *status)
{
	struct ieee80211_local *local = dev->priv;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct sta_info *sta;
	struct sta_rate_control *srctrl;

        sta = sta_info_get(local, hdr->addr1);

	if (!sta)
            return;

	srctrl = sta->rate_ctrl_priv;
	srctrl->tx_num_xmit++;
	if (status->excessive_retries) {
		sta->antenna_sel = sta->antenna_sel == 1 ? 2 : 1;
		if (local->sta_antenna_sel == STA_ANTENNA_SEL_SW_CTRL_DEBUG) {
			printk(KERN_DEBUG "%s: " MACSTR " TX antenna --> %d "
			       "(@%lu)\n",
			       dev->name, MAC2STR(hdr->addr1),
			       sta->antenna_sel, jiffies);
		}
		srctrl->tx_num_failures++;
		sta->tx_retry_failed++;
		sta->tx_num_consecutive_failures++;
		sta->tx_num_mpdu_fail++;
	} else {
		sta->last_ack_rssi[0] = sta->last_ack_rssi[1];
		sta->last_ack_rssi[1] = sta->last_ack_rssi[2];
		sta->last_ack_rssi[2] = status->ack_signal;
		sta->tx_num_consecutive_failures = 0;
		sta->tx_num_mpdu_ok++;
	}
	sta->tx_retry_count += status->retry_count;
	sta->tx_num_mpdu_fail += status->retry_count;

	if (time_after(jiffies,
		       srctrl->last_rate_change + RATE_CONTROL_INTERVAL) &&
		srctrl->tx_num_xmit > RATE_CONTROL_MIN_TX) {
		u32 per_failed;
		srctrl->last_rate_change = jiffies;

		per_failed = (100 * sta->tx_num_mpdu_fail) /
			(sta->tx_num_mpdu_fail + sta->tx_num_mpdu_ok);
		/* TODO: calculate average per_failed to make adjusting
		 * parameters easier */
#if 0
		if (net_ratelimit()) {
			printk(KERN_DEBUG "MPDU fail=%d ok=%d per_failed=%d\n",
			       sta->tx_num_mpdu_fail, sta->tx_num_mpdu_ok,
			       per_failed);
		}
#endif

		if (per_failed > local->rate_ctrl_num_down) {
			rate_control_rate_dec(local, sta);
		} else if (per_failed < local->rate_ctrl_num_up) {
			rate_control_rate_inc(local, sta);
		}
		srctrl->tx_avg_rate_sum += local->curr_rates[sta->txrate].rate;
		srctrl->tx_avg_rate_num++;
		srctrl->tx_num_failures = 0;
		srctrl->tx_num_xmit = 0;
	} else if (sta->tx_num_consecutive_failures >=
		   RATE_CONTROL_EMERG_DEC) {
		rate_control_rate_dec(local, sta);
	}

	if (srctrl->avg_rate_update + 60 * HZ < jiffies) {
		srctrl->avg_rate_update = jiffies;
		if (srctrl->tx_avg_rate_num > 0) {
#ifdef CONFIG_IEEE80211_VERBOSE_DEBUG
			printk(KERN_DEBUG "%s: STA " MACSTR " Average rate: "
			       "%d (%d/%d)\n",
                               dev->name, MAC2STR(sta->addr),
			       srctrl->tx_avg_rate_sum /
			       srctrl->tx_avg_rate_num,
			       srctrl->tx_avg_rate_sum,
			       srctrl->tx_avg_rate_num);
#endif /* CONFIG_IEEE80211_VERBOSE_DEBUG */
			srctrl->tx_avg_rate_sum = 0;
			srctrl->tx_avg_rate_num = 0;
		}
	}

	sta_info_release(local, sta);
}


static struct ieee80211_rate *
rate_control_simple_get_rate(struct net_device *dev, struct sk_buff *skb,
			     struct rate_control_extra *extra)
{
	struct ieee80211_local *local = dev->priv;
	struct ieee80211_sub_if_data *sdata;
	struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
	struct sta_info *sta;
	int rateidx, nonerp_idx;
	u16 fc;

	memset(extra, 0, sizeof(*extra));

	fc = le16_to_cpu(hdr->frame_control);
	if (WLAN_FC_GET_TYPE(fc) != WLAN_FC_TYPE_DATA ||
	    (hdr->addr1[0] & 0x01)) {
		/* Send management frames and broadcast/multicast data using
		 * lowest rate. */
		/* TODO: this could probably be improved.. */
		return rate_control_lowest_rate(local);
	}

	sta = sta_info_get(local, hdr->addr1);

	if (!sta)
		return rate_control_lowest_rate(local);

	sdata = IEEE80211_DEV_TO_SUB_IF(dev);
	if (sdata->bss && sdata->bss->force_unicast_rateidx > -1)
		sta->txrate = sdata->bss->force_unicast_rateidx;

	rateidx = sta->txrate;

	if (rateidx >= local->num_curr_rates)
		rateidx = local->num_curr_rates - 1;

	sta->last_txrate = rateidx;
	nonerp_idx = rateidx;
	while (nonerp_idx > 0 &&
	       ((local->curr_rates[nonerp_idx].flags & IEEE80211_RATE_ERP) ||
		!(local->curr_rates[nonerp_idx].flags &
		  IEEE80211_RATE_SUPPORTED) ||
		!(sta->supp_rates & BIT(nonerp_idx))))
		nonerp_idx--;
	extra->nonerp_idx = nonerp_idx;
	extra->nonerp = &local->curr_rates[extra->nonerp_idx];

	sta_info_release(local, sta);

	return &local->curr_rates[rateidx];
}


static void rate_control_simple_rate_init(struct ieee80211_local *local,
					  struct sta_info *sta)
{
	int i;
	sta->txrate = 0;
	/* TODO: what is a good starting rate for STA? About middle? Maybe not
	 * the lowest or the highest rate.. Could consider using RSSI from
	 * previous packets? Need to have IEEE 802.1X auth succeed immediately
	 * after assoc.. */
	for (i = 0; i < local->num_curr_rates; i++) {
		if ((sta->supp_rates & BIT(i)) &&
		    (local->curr_rates[i].flags & IEEE80211_RATE_SUPPORTED))
			sta->txrate = i;
	}
}


static void * rate_control_simple_alloc(struct ieee80211_local *local)
{
	struct global_rate_control *rctrl;

	rctrl = kmalloc(sizeof(*rctrl), GFP_ATOMIC);
	if (rctrl == NULL) {
		return NULL;
	}
	memset(rctrl, 0, sizeof(*rctrl));
	return rctrl;
}


static void rate_control_simple_free(void *priv)
{
	struct global_rate_control *rctrl = priv;
	kfree(rctrl);
}


static void rate_control_simple_clear(void *priv)
{
}


static void * rate_control_simple_alloc_sta(void)
{
	struct sta_rate_control *rctrl;

	rctrl = kmalloc(sizeof(*rctrl), GFP_ATOMIC);
	if (rctrl == NULL) {
		return NULL;
	}
	memset(rctrl, 0, sizeof(*rctrl));
	return rctrl;
}


static void rate_control_simple_free_sta(void *priv)
{
	struct sta_rate_control *rctrl = priv;
	kfree(rctrl);
}


static int rate_control_simple_status_sta(struct ieee80211_local *local,
					  struct sta_info *sta, char *buf)
{
	char *p = buf;
	struct sta_rate_control *srctrl = sta->rate_ctrl_priv;

	p += sprintf(p, "tx_avg_rate_sum=%d\n", srctrl->tx_avg_rate_sum);
	p += sprintf(p, "tx_avg_rate_num=%d\n", srctrl->tx_avg_rate_num);
	if (srctrl->tx_avg_rate_num)
		p += sprintf(p, "tx_avg_rate_avg=%d\n",
			     srctrl->tx_avg_rate_sum /
			     srctrl->tx_avg_rate_num);
	return p - buf;
}


static int rate_control_simple_status_global(struct ieee80211_local *local,
					     char *buf)
{
	return 0;
}


static struct rate_control_ops rate_control_simple = {
	.name = "simple",
	.tx_status = rate_control_simple_tx_status,
	.get_rate = rate_control_simple_get_rate,
	.rate_init = rate_control_simple_rate_init,
	.clear = rate_control_simple_clear,
	.status_sta = rate_control_simple_status_sta,
	.status_global = rate_control_simple_status_global,
	.alloc = rate_control_simple_alloc,
	.free = rate_control_simple_free,
	.alloc_sta = rate_control_simple_alloc_sta,
	.free_sta = rate_control_simple_free_sta,
};


int __init rate_control_simple_init(void)
{
	return ieee80211_rate_control_register(&rate_control_simple);
}


static void __exit rate_control_simple_exit(void)
{
	ieee80211_rate_control_unregister(&rate_control_simple);
}


module_init(rate_control_simple_init);
module_exit(rate_control_simple_exit);