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