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CommitLineData
f0706e82
JB
1/*
2 * Copyright 2002-2005, Instant802 Networks, Inc.
3 * Copyright 2005-2006, Devicescape Software, Inc.
4 * Copyright (c) 2006 Jiri Benc <jbenc@suse.cz>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/kernel.h>
ff688089 12#include <linux/rtnetlink.h>
5a0e3ad6 13#include <linux/slab.h>
2c8dccc7 14#include "rate.h"
f0706e82 15#include "ieee80211_i.h"
4b7679a5 16#include "debugfs.h"
f0706e82
JB
17
18struct rate_control_alg {
19 struct list_head list;
20 struct rate_control_ops *ops;
21};
22
23static LIST_HEAD(rate_ctrl_algs);
24static DEFINE_MUTEX(rate_ctrl_mutex);
25
c21b39ac
SB
26static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT;
27module_param(ieee80211_default_rc_algo, charp, 0644);
28MODULE_PARM_DESC(ieee80211_default_rc_algo,
29 "Default rate control algorithm for mac80211 to use");
30
f0706e82
JB
31int ieee80211_rate_control_register(struct rate_control_ops *ops)
32{
33 struct rate_control_alg *alg;
34
ac71c691
JB
35 if (!ops->name)
36 return -EINVAL;
37
999acd9c
JB
38 mutex_lock(&rate_ctrl_mutex);
39 list_for_each_entry(alg, &rate_ctrl_algs, list) {
40 if (!strcmp(alg->ops->name, ops->name)) {
41 /* don't register an algorithm twice */
42 WARN_ON(1);
b808ab16 43 mutex_unlock(&rate_ctrl_mutex);
999acd9c
JB
44 return -EALREADY;
45 }
46 }
47
dd00cc48 48 alg = kzalloc(sizeof(*alg), GFP_KERNEL);
f0706e82 49 if (alg == NULL) {
999acd9c 50 mutex_unlock(&rate_ctrl_mutex);
f0706e82
JB
51 return -ENOMEM;
52 }
f0706e82
JB
53 alg->ops = ops;
54
f0706e82
JB
55 list_add_tail(&alg->list, &rate_ctrl_algs);
56 mutex_unlock(&rate_ctrl_mutex);
57
58 return 0;
59}
60EXPORT_SYMBOL(ieee80211_rate_control_register);
61
62void ieee80211_rate_control_unregister(struct rate_control_ops *ops)
63{
64 struct rate_control_alg *alg;
65
66 mutex_lock(&rate_ctrl_mutex);
67 list_for_each_entry(alg, &rate_ctrl_algs, list) {
68 if (alg->ops == ops) {
69 list_del(&alg->list);
20880e89 70 kfree(alg);
f0706e82
JB
71 break;
72 }
73 }
74 mutex_unlock(&rate_ctrl_mutex);
f0706e82
JB
75}
76EXPORT_SYMBOL(ieee80211_rate_control_unregister);
77
78static struct rate_control_ops *
79ieee80211_try_rate_control_ops_get(const char *name)
80{
81 struct rate_control_alg *alg;
82 struct rate_control_ops *ops = NULL;
83
ac71c691
JB
84 if (!name)
85 return NULL;
86
f0706e82
JB
87 mutex_lock(&rate_ctrl_mutex);
88 list_for_each_entry(alg, &rate_ctrl_algs, list) {
ac71c691 89 if (!strcmp(alg->ops->name, name))
f0706e82
JB
90 if (try_module_get(alg->ops->module)) {
91 ops = alg->ops;
92 break;
93 }
94 }
95 mutex_unlock(&rate_ctrl_mutex);
96 return ops;
97}
98
c21b39ac 99/* Get the rate control algorithm. */
f0706e82
JB
100static struct rate_control_ops *
101ieee80211_rate_control_ops_get(const char *name)
102{
103 struct rate_control_ops *ops;
c21b39ac 104 const char *alg_name;
f0706e82 105
ac71c691 106 if (!name)
c21b39ac
SB
107 alg_name = ieee80211_default_rc_algo;
108 else
109 alg_name = name;
ac71c691 110
c21b39ac 111 ops = ieee80211_try_rate_control_ops_get(alg_name);
f0706e82 112 if (!ops) {
c21b39ac
SB
113 request_module("rc80211_%s", alg_name);
114 ops = ieee80211_try_rate_control_ops_get(alg_name);
f0706e82 115 }
c21b39ac
SB
116 if (!ops && name)
117 /* try default if specific alg requested but not found */
118 ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo);
119
4b475898
JB
120 /* try built-in one if specific alg requested but not found */
121 if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT))
122 ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT);
123
f0706e82
JB
124 return ops;
125}
126
127static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops)
128{
129 module_put(ops->module);
130}
131
4b7679a5
JB
132#ifdef CONFIG_MAC80211_DEBUGFS
133static ssize_t rcname_read(struct file *file, char __user *userbuf,
134 size_t count, loff_t *ppos)
135{
136 struct rate_control_ref *ref = file->private_data;
137 int len = strlen(ref->ops->name);
138
139 return simple_read_from_buffer(userbuf, count, ppos,
140 ref->ops->name, len);
141}
142
143static const struct file_operations rcname_ops = {
144 .read = rcname_read,
145 .open = mac80211_open_file_generic,
146};
147#endif
148
209c671d 149static struct rate_control_ref *rate_control_alloc(const char *name,
f0706e82
JB
150 struct ieee80211_local *local)
151{
4b7679a5 152 struct dentry *debugfsdir = NULL;
f0706e82
JB
153 struct rate_control_ref *ref;
154
155 ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL);
156 if (!ref)
157 goto fail_ref;
158 kref_init(&ref->kref);
4b7679a5 159 ref->local = local;
f0706e82
JB
160 ref->ops = ieee80211_rate_control_ops_get(name);
161 if (!ref->ops)
162 goto fail_ops;
4b7679a5
JB
163
164#ifdef CONFIG_MAC80211_DEBUGFS
165 debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir);
166 local->debugfs.rcdir = debugfsdir;
7bcfaf2f 167 debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops);
4b7679a5
JB
168#endif
169
170 ref->priv = ref->ops->alloc(&local->hw, debugfsdir);
f0706e82
JB
171 if (!ref->priv)
172 goto fail_priv;
173 return ref;
174
175fail_priv:
176 ieee80211_rate_control_ops_put(ref->ops);
177fail_ops:
178 kfree(ref);
179fail_ref:
180 return NULL;
181}
182
183static void rate_control_release(struct kref *kref)
184{
185 struct rate_control_ref *ctrl_ref;
186
187 ctrl_ref = container_of(kref, struct rate_control_ref, kref);
188 ctrl_ref->ops->free(ctrl_ref->priv);
4b7679a5
JB
189
190#ifdef CONFIG_MAC80211_DEBUGFS
7bcfaf2f 191 debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir);
4b7679a5
JB
192 ctrl_ref->local->debugfs.rcdir = NULL;
193#endif
194
f0706e82
JB
195 ieee80211_rate_control_ops_put(ctrl_ref->ops);
196 kfree(ctrl_ref);
197}
198
4c6d4f5c
LR
199static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc)
200{
201 struct sk_buff *skb = txrc->skb;
202 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data;
203 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
204 __le16 fc;
205
206 fc = hdr->frame_control;
207
208 return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc));
209}
210
e00cfce0
JM
211static void rc_send_low_broadcast(s8 *idx, u32 basic_rates, u8 max_rate_idx)
212{
213 u8 i;
214
215 if (basic_rates == 0)
216 return; /* assume basic rates unknown and accept rate */
217 if (*idx < 0)
218 return;
219 if (basic_rates & (1 << *idx))
220 return; /* selected rate is a basic rate */
221
222 for (i = *idx + 1; i <= max_rate_idx; i++) {
223 if (basic_rates & (1 << i)) {
224 *idx = i;
225 return;
226 }
227 }
228
229 /* could not find a basic rate; use original selection */
230}
231
4c6d4f5c
LR
232bool rate_control_send_low(struct ieee80211_sta *sta,
233 void *priv_sta,
234 struct ieee80211_tx_rate_control *txrc)
235{
236 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
237
238 if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) {
239 info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta);
240 info->control.rates[0].count =
241 (info->flags & IEEE80211_TX_CTL_NO_ACK) ?
242 1 : txrc->hw->max_rate_tries;
e00cfce0
JM
243 if (!sta && txrc->ap)
244 rc_send_low_broadcast(&info->control.rates[0].idx,
245 txrc->bss_conf->basic_rates,
246 txrc->sband->n_bitrates);
4c6d4f5c
LR
247 return true;
248 }
249 return false;
250}
251EXPORT_SYMBOL(rate_control_send_low);
252
37eb0b16
JM
253static void rate_idx_match_mask(struct ieee80211_tx_rate *rate,
254 int n_bitrates, u32 mask)
255{
256 int j;
257
258 /* See whether the selected rate or anything below it is allowed. */
259 for (j = rate->idx; j >= 0; j--) {
260 if (mask & (1 << j)) {
261 /* Okay, found a suitable rate. Use it. */
262 rate->idx = j;
263 return;
264 }
265 }
266
267 /* Try to find a higher rate that would be allowed */
268 for (j = rate->idx + 1; j < n_bitrates; j++) {
269 if (mask & (1 << j)) {
270 /* Okay, found a suitable rate. Use it. */
271 rate->idx = j;
272 return;
273 }
274 }
275
276 /*
277 * Uh.. No suitable rate exists. This should not really happen with
278 * sane TX rate mask configurations. However, should someone manage to
279 * configure supported rates and TX rate mask in incompatible way,
280 * allow the frame to be transmitted with whatever the rate control
281 * selected.
282 */
283}
284
4b7679a5 285void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
e6a9854b
JB
286 struct sta_info *sta,
287 struct ieee80211_tx_rate_control *txrc)
1abbe498 288{
4b7679a5
JB
289 struct rate_control_ref *ref = sdata->local->rate_ctrl;
290 void *priv_sta = NULL;
291 struct ieee80211_sta *ista = NULL;
e6a9854b 292 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb);
1abbe498 293 int i;
37eb0b16 294 u32 mask;
1abbe498 295
4b7679a5
JB
296 if (sta) {
297 ista = &sta->sta;
298 priv_sta = sta->rate_ctrl_priv;
299 }
300
e6a9854b
JB
301 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
302 info->control.rates[i].idx = -1;
303 info->control.rates[i].flags = 0;
304 info->control.rates[i].count = 1;
305 }
306
5affcd6b
JO
307 if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL)
308 return;
309
37eb0b16 310 ref->ops->get_rate(ref->priv, ista, priv_sta, txrc);
e6a9854b
JB
311
312 /*
37eb0b16
JM
313 * Try to enforce the rateidx mask the user wanted. skip this if the
314 * default mask (allow all rates) is used to save some processing for
315 * the common case.
e6a9854b 316 */
37eb0b16
JM
317 mask = sdata->rc_rateidx_mask[info->band];
318 if (mask != (1 << txrc->sband->n_bitrates) - 1) {
319 if (sta) {
320 /* Filter out rates that the STA does not support */
321 mask &= sta->sta.supp_rates[info->band];
322 }
323 /*
324 * Make sure the rate index selected for each TX rate is
325 * included in the configured mask and change the rate indexes
326 * if needed.
327 */
e6a9854b 328 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) {
37eb0b16 329 /* Rate masking supports only legacy rates for now */
e6a9854b
JB
330 if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS)
331 continue;
37eb0b16
JM
332 rate_idx_match_mask(&info->control.rates[i],
333 txrc->sband->n_bitrates, mask);
334 }
1abbe498 335 }
e6a9854b
JB
336
337 BUG_ON(info->control.rates[0].idx < 0);
1abbe498
MN
338}
339
f0706e82
JB
340struct rate_control_ref *rate_control_get(struct rate_control_ref *ref)
341{
342 kref_get(&ref->kref);
343 return ref;
344}
345
346void rate_control_put(struct rate_control_ref *ref)
347{
348 kref_put(&ref->kref, rate_control_release);
349}
ff688089
JB
350
351int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local,
352 const char *name)
353{
354 struct rate_control_ref *ref, *old;
355
356 ASSERT_RTNL();
af65cd96 357
3b8d81e0 358 if (local->open_count)
ff688089
JB
359 return -EBUSY;
360
af65cd96
JB
361 if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) {
362 if (WARN_ON(!local->ops->set_rts_threshold))
363 return -EINVAL;
364 return 0;
365 }
366
ff688089
JB
367 ref = rate_control_alloc(name, local);
368 if (!ref) {
0fb9a9ec
JP
369 wiphy_warn(local->hw.wiphy,
370 "Failed to select rate control algorithm\n");
ff688089
JB
371 return -ENOENT;
372 }
373
374 old = local->rate_ctrl;
375 local->rate_ctrl = ref;
376 if (old) {
377 rate_control_put(old);
378 sta_info_flush(local, NULL);
379 }
380
0fb9a9ec
JP
381 wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n",
382 ref->ops->name);
ff688089 383
ff688089
JB
384 return 0;
385}
386
387void rate_control_deinitialize(struct ieee80211_local *local)
388{
389 struct rate_control_ref *ref;
390
391 ref = local->rate_ctrl;
af65cd96
JB
392
393 if (!ref)
394 return;
395
ff688089
JB
396 local->rate_ctrl = NULL;
397 rate_control_put(ref);
398}
c21b39ac 399