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> 12 #include <linux/rtnetlink.h> 13 #include <linux/slab.h> 14 #include <linux/module.h> 15 #include "rate.h" 16 #include "ieee80211_i.h" 17 #include "debugfs.h" 18 19 struct rate_control_alg { 20 struct list_head list; 21 struct rate_control_ops *ops; 22 }; 23 24 static LIST_HEAD(rate_ctrl_algs); 25 static DEFINE_MUTEX(rate_ctrl_mutex); 26 27 static char *ieee80211_default_rc_algo = CONFIG_MAC80211_RC_DEFAULT; 28 module_param(ieee80211_default_rc_algo, charp, 0644); 29 MODULE_PARM_DESC(ieee80211_default_rc_algo, 30 "Default rate control algorithm for mac80211 to use"); 31 32 int ieee80211_rate_control_register(struct rate_control_ops *ops) 33 { 34 struct rate_control_alg *alg; 35 36 if (!ops->name) 37 return -EINVAL; 38 39 mutex_lock(&rate_ctrl_mutex); 40 list_for_each_entry(alg, &rate_ctrl_algs, list) { 41 if (!strcmp(alg->ops->name, ops->name)) { 42 /* don't register an algorithm twice */ 43 WARN_ON(1); 44 mutex_unlock(&rate_ctrl_mutex); 45 return -EALREADY; 46 } 47 } 48 49 alg = kzalloc(sizeof(*alg), GFP_KERNEL); 50 if (alg == NULL) { 51 mutex_unlock(&rate_ctrl_mutex); 52 return -ENOMEM; 53 } 54 alg->ops = ops; 55 56 list_add_tail(&alg->list, &rate_ctrl_algs); 57 mutex_unlock(&rate_ctrl_mutex); 58 59 return 0; 60 } 61 EXPORT_SYMBOL(ieee80211_rate_control_register); 62 63 void ieee80211_rate_control_unregister(struct rate_control_ops *ops) 64 { 65 struct rate_control_alg *alg; 66 67 mutex_lock(&rate_ctrl_mutex); 68 list_for_each_entry(alg, &rate_ctrl_algs, list) { 69 if (alg->ops == ops) { 70 list_del(&alg->list); 71 kfree(alg); 72 break; 73 } 74 } 75 mutex_unlock(&rate_ctrl_mutex); 76 } 77 EXPORT_SYMBOL(ieee80211_rate_control_unregister); 78 79 static struct rate_control_ops * 80 ieee80211_try_rate_control_ops_get(const char *name) 81 { 82 struct rate_control_alg *alg; 83 struct rate_control_ops *ops = NULL; 84 85 if (!name) 86 return NULL; 87 88 mutex_lock(&rate_ctrl_mutex); 89 list_for_each_entry(alg, &rate_ctrl_algs, list) { 90 if (!strcmp(alg->ops->name, name)) 91 if (try_module_get(alg->ops->module)) { 92 ops = alg->ops; 93 break; 94 } 95 } 96 mutex_unlock(&rate_ctrl_mutex); 97 return ops; 98 } 99 100 /* Get the rate control algorithm. */ 101 static struct rate_control_ops * 102 ieee80211_rate_control_ops_get(const char *name) 103 { 104 struct rate_control_ops *ops; 105 const char *alg_name; 106 107 kparam_block_sysfs_write(ieee80211_default_rc_algo); 108 if (!name) 109 alg_name = ieee80211_default_rc_algo; 110 else 111 alg_name = name; 112 113 ops = ieee80211_try_rate_control_ops_get(alg_name); 114 if (!ops) { 115 request_module("rc80211_%s", alg_name); 116 ops = ieee80211_try_rate_control_ops_get(alg_name); 117 } 118 if (!ops && name) 119 /* try default if specific alg requested but not found */ 120 ops = ieee80211_try_rate_control_ops_get(ieee80211_default_rc_algo); 121 122 /* try built-in one if specific alg requested but not found */ 123 if (!ops && strlen(CONFIG_MAC80211_RC_DEFAULT)) 124 ops = ieee80211_try_rate_control_ops_get(CONFIG_MAC80211_RC_DEFAULT); 125 kparam_unblock_sysfs_write(ieee80211_default_rc_algo); 126 127 return ops; 128 } 129 130 static void ieee80211_rate_control_ops_put(struct rate_control_ops *ops) 131 { 132 module_put(ops->module); 133 } 134 135 #ifdef CONFIG_MAC80211_DEBUGFS 136 static ssize_t rcname_read(struct file *file, char __user *userbuf, 137 size_t count, loff_t *ppos) 138 { 139 struct rate_control_ref *ref = file->private_data; 140 int len = strlen(ref->ops->name); 141 142 return simple_read_from_buffer(userbuf, count, ppos, 143 ref->ops->name, len); 144 } 145 146 static const struct file_operations rcname_ops = { 147 .read = rcname_read, 148 .open = mac80211_open_file_generic, 149 .llseek = default_llseek, 150 }; 151 #endif 152 153 static struct rate_control_ref *rate_control_alloc(const char *name, 154 struct ieee80211_local *local) 155 { 156 struct dentry *debugfsdir = NULL; 157 struct rate_control_ref *ref; 158 159 ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL); 160 if (!ref) 161 goto fail_ref; 162 kref_init(&ref->kref); 163 ref->local = local; 164 ref->ops = ieee80211_rate_control_ops_get(name); 165 if (!ref->ops) 166 goto fail_ops; 167 168 #ifdef CONFIG_MAC80211_DEBUGFS 169 debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir); 170 local->debugfs.rcdir = debugfsdir; 171 debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops); 172 #endif 173 174 ref->priv = ref->ops->alloc(&local->hw, debugfsdir); 175 if (!ref->priv) 176 goto fail_priv; 177 return ref; 178 179 fail_priv: 180 ieee80211_rate_control_ops_put(ref->ops); 181 fail_ops: 182 kfree(ref); 183 fail_ref: 184 return NULL; 185 } 186 187 static void rate_control_release(struct kref *kref) 188 { 189 struct rate_control_ref *ctrl_ref; 190 191 ctrl_ref = container_of(kref, struct rate_control_ref, kref); 192 ctrl_ref->ops->free(ctrl_ref->priv); 193 194 #ifdef CONFIG_MAC80211_DEBUGFS 195 debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir); 196 ctrl_ref->local->debugfs.rcdir = NULL; 197 #endif 198 199 ieee80211_rate_control_ops_put(ctrl_ref->ops); 200 kfree(ctrl_ref); 201 } 202 203 static bool rc_no_data_or_no_ack_use_min(struct ieee80211_tx_rate_control *txrc) 204 { 205 struct sk_buff *skb = txrc->skb; 206 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 207 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 208 __le16 fc; 209 210 fc = hdr->frame_control; 211 212 return (info->flags & (IEEE80211_TX_CTL_NO_ACK | 213 IEEE80211_TX_CTL_USE_MINRATE)) || 214 !ieee80211_is_data(fc); 215 } 216 217 static void rc_send_low_broadcast(s8 *idx, u32 basic_rates, 218 struct ieee80211_supported_band *sband) 219 { 220 u8 i; 221 222 if (basic_rates == 0) 223 return; /* assume basic rates unknown and accept rate */ 224 if (*idx < 0) 225 return; 226 if (basic_rates & (1 << *idx)) 227 return; /* selected rate is a basic rate */ 228 229 for (i = *idx + 1; i <= sband->n_bitrates; i++) { 230 if (basic_rates & (1 << i)) { 231 *idx = i; 232 return; 233 } 234 } 235 236 /* could not find a basic rate; use original selection */ 237 } 238 239 static inline s8 240 rate_lowest_non_cck_index(struct ieee80211_supported_band *sband, 241 struct ieee80211_sta *sta) 242 { 243 int i; 244 245 for (i = 0; i < sband->n_bitrates; i++) { 246 struct ieee80211_rate *srate = &sband->bitrates[i]; 247 if ((srate->bitrate == 10) || (srate->bitrate == 20) || 248 (srate->bitrate == 55) || (srate->bitrate == 110)) 249 continue; 250 251 if (rate_supported(sta, sband->band, i)) 252 return i; 253 } 254 255 /* No matching rate found */ 256 return 0; 257 } 258 259 260 bool rate_control_send_low(struct ieee80211_sta *sta, 261 void *priv_sta, 262 struct ieee80211_tx_rate_control *txrc) 263 { 264 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 265 struct ieee80211_supported_band *sband = txrc->sband; 266 int mcast_rate; 267 268 if (!sta || !priv_sta || rc_no_data_or_no_ack_use_min(txrc)) { 269 if ((sband->band != IEEE80211_BAND_2GHZ) || 270 !(info->flags & IEEE80211_TX_CTL_NO_CCK_RATE)) 271 info->control.rates[0].idx = 272 rate_lowest_index(txrc->sband, sta); 273 else 274 info->control.rates[0].idx = 275 rate_lowest_non_cck_index(txrc->sband, sta); 276 info->control.rates[0].count = 277 (info->flags & IEEE80211_TX_CTL_NO_ACK) ? 278 1 : txrc->hw->max_rate_tries; 279 if (!sta && txrc->bss) { 280 mcast_rate = txrc->bss_conf->mcast_rate[sband->band]; 281 if (mcast_rate > 0) { 282 info->control.rates[0].idx = mcast_rate - 1; 283 return true; 284 } 285 286 rc_send_low_broadcast(&info->control.rates[0].idx, 287 txrc->bss_conf->basic_rates, 288 sband); 289 } 290 return true; 291 } 292 return false; 293 } 294 EXPORT_SYMBOL(rate_control_send_low); 295 296 static void rate_idx_match_mask(struct ieee80211_tx_rate *rate, 297 int n_bitrates, u32 mask) 298 { 299 int j; 300 301 /* See whether the selected rate or anything below it is allowed. */ 302 for (j = rate->idx; j >= 0; j--) { 303 if (mask & (1 << j)) { 304 /* Okay, found a suitable rate. Use it. */ 305 rate->idx = j; 306 return; 307 } 308 } 309 310 /* Try to find a higher rate that would be allowed */ 311 for (j = rate->idx + 1; j < n_bitrates; j++) { 312 if (mask & (1 << j)) { 313 /* Okay, found a suitable rate. Use it. */ 314 rate->idx = j; 315 return; 316 } 317 } 318 319 /* 320 * Uh.. No suitable rate exists. This should not really happen with 321 * sane TX rate mask configurations. However, should someone manage to 322 * configure supported rates and TX rate mask in incompatible way, 323 * allow the frame to be transmitted with whatever the rate control 324 * selected. 325 */ 326 } 327 328 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata, 329 struct sta_info *sta, 330 struct ieee80211_tx_rate_control *txrc) 331 { 332 struct rate_control_ref *ref = sdata->local->rate_ctrl; 333 void *priv_sta = NULL; 334 struct ieee80211_sta *ista = NULL; 335 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 336 int i; 337 u32 mask; 338 339 if (sta && test_sta_flag(sta, WLAN_STA_RATE_CONTROL)) { 340 ista = &sta->sta; 341 priv_sta = sta->rate_ctrl_priv; 342 } 343 344 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { 345 info->control.rates[i].idx = -1; 346 info->control.rates[i].flags = 0; 347 info->control.rates[i].count = 0; 348 } 349 350 if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) 351 return; 352 353 ref->ops->get_rate(ref->priv, ista, priv_sta, txrc); 354 355 /* 356 * Try to enforce the rateidx mask the user wanted. skip this if the 357 * default mask (allow all rates) is used to save some processing for 358 * the common case. 359 */ 360 mask = sdata->rc_rateidx_mask[info->band]; 361 if (mask != (1 << txrc->sband->n_bitrates) - 1) { 362 if (sta) { 363 /* Filter out rates that the STA does not support */ 364 mask &= sta->sta.supp_rates[info->band]; 365 } 366 /* 367 * Make sure the rate index selected for each TX rate is 368 * included in the configured mask and change the rate indexes 369 * if needed. 370 */ 371 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { 372 /* Skip invalid rates */ 373 if (info->control.rates[i].idx < 0) 374 break; 375 /* Rate masking supports only legacy rates for now */ 376 if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS) 377 continue; 378 rate_idx_match_mask(&info->control.rates[i], 379 txrc->sband->n_bitrates, mask); 380 } 381 } 382 383 BUG_ON(info->control.rates[0].idx < 0); 384 } 385 386 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref) 387 { 388 kref_get(&ref->kref); 389 return ref; 390 } 391 392 void rate_control_put(struct rate_control_ref *ref) 393 { 394 kref_put(&ref->kref, rate_control_release); 395 } 396 397 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local, 398 const char *name) 399 { 400 struct rate_control_ref *ref, *old; 401 402 ASSERT_RTNL(); 403 404 if (local->open_count) 405 return -EBUSY; 406 407 if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) { 408 if (WARN_ON(!local->ops->set_rts_threshold)) 409 return -EINVAL; 410 return 0; 411 } 412 413 ref = rate_control_alloc(name, local); 414 if (!ref) { 415 wiphy_warn(local->hw.wiphy, 416 "Failed to select rate control algorithm\n"); 417 return -ENOENT; 418 } 419 420 old = local->rate_ctrl; 421 local->rate_ctrl = ref; 422 if (old) { 423 rate_control_put(old); 424 sta_info_flush(local, NULL); 425 } 426 427 wiphy_debug(local->hw.wiphy, "Selected rate control algorithm '%s'\n", 428 ref->ops->name); 429 430 return 0; 431 } 432 433 void rate_control_deinitialize(struct ieee80211_local *local) 434 { 435 struct rate_control_ref *ref; 436 437 ref = local->rate_ctrl; 438 439 if (!ref) 440 return; 441 442 local->rate_ctrl = NULL; 443 rate_control_put(ref); 444 } 445 446