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 .llseek = default_llseek, 149 }; 150 #endif 151 152 static struct rate_control_ref *rate_control_alloc(const char *name, 153 struct ieee80211_local *local) 154 { 155 struct dentry *debugfsdir = NULL; 156 struct rate_control_ref *ref; 157 158 ref = kmalloc(sizeof(struct rate_control_ref), GFP_KERNEL); 159 if (!ref) 160 goto fail_ref; 161 kref_init(&ref->kref); 162 ref->local = local; 163 ref->ops = ieee80211_rate_control_ops_get(name); 164 if (!ref->ops) 165 goto fail_ops; 166 167 #ifdef CONFIG_MAC80211_DEBUGFS 168 debugfsdir = debugfs_create_dir("rc", local->hw.wiphy->debugfsdir); 169 local->debugfs.rcdir = debugfsdir; 170 debugfs_create_file("name", 0400, debugfsdir, ref, &rcname_ops); 171 #endif 172 173 ref->priv = ref->ops->alloc(&local->hw, debugfsdir); 174 if (!ref->priv) 175 goto fail_priv; 176 return ref; 177 178 fail_priv: 179 ieee80211_rate_control_ops_put(ref->ops); 180 fail_ops: 181 kfree(ref); 182 fail_ref: 183 return NULL; 184 } 185 186 static void rate_control_release(struct kref *kref) 187 { 188 struct rate_control_ref *ctrl_ref; 189 190 ctrl_ref = container_of(kref, struct rate_control_ref, kref); 191 ctrl_ref->ops->free(ctrl_ref->priv); 192 193 #ifdef CONFIG_MAC80211_DEBUGFS 194 debugfs_remove_recursive(ctrl_ref->local->debugfs.rcdir); 195 ctrl_ref->local->debugfs.rcdir = NULL; 196 #endif 197 198 ieee80211_rate_control_ops_put(ctrl_ref->ops); 199 kfree(ctrl_ref); 200 } 201 202 static bool rc_no_data_or_no_ack(struct ieee80211_tx_rate_control *txrc) 203 { 204 struct sk_buff *skb = txrc->skb; 205 struct ieee80211_hdr *hdr = (struct ieee80211_hdr *) skb->data; 206 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb); 207 __le16 fc; 208 209 fc = hdr->frame_control; 210 211 return ((info->flags & IEEE80211_TX_CTL_NO_ACK) || !ieee80211_is_data(fc)); 212 } 213 214 static void rc_send_low_broadcast(s8 *idx, u32 basic_rates, u8 max_rate_idx) 215 { 216 u8 i; 217 218 if (basic_rates == 0) 219 return; /* assume basic rates unknown and accept rate */ 220 if (*idx < 0) 221 return; 222 if (basic_rates & (1 << *idx)) 223 return; /* selected rate is a basic rate */ 224 225 for (i = *idx + 1; i <= max_rate_idx; i++) { 226 if (basic_rates & (1 << i)) { 227 *idx = i; 228 return; 229 } 230 } 231 232 /* could not find a basic rate; use original selection */ 233 } 234 235 bool rate_control_send_low(struct ieee80211_sta *sta, 236 void *priv_sta, 237 struct ieee80211_tx_rate_control *txrc) 238 { 239 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 240 241 if (!sta || !priv_sta || rc_no_data_or_no_ack(txrc)) { 242 info->control.rates[0].idx = rate_lowest_index(txrc->sband, sta); 243 info->control.rates[0].count = 244 (info->flags & IEEE80211_TX_CTL_NO_ACK) ? 245 1 : txrc->hw->max_rate_tries; 246 if (!sta && txrc->ap) 247 rc_send_low_broadcast(&info->control.rates[0].idx, 248 txrc->bss_conf->basic_rates, 249 txrc->sband->n_bitrates); 250 return true; 251 } 252 return false; 253 } 254 EXPORT_SYMBOL(rate_control_send_low); 255 256 static void rate_idx_match_mask(struct ieee80211_tx_rate *rate, 257 int n_bitrates, u32 mask) 258 { 259 int j; 260 261 /* See whether the selected rate or anything below it is allowed. */ 262 for (j = rate->idx; j >= 0; j--) { 263 if (mask & (1 << j)) { 264 /* Okay, found a suitable rate. Use it. */ 265 rate->idx = j; 266 return; 267 } 268 } 269 270 /* Try to find a higher rate that would be allowed */ 271 for (j = rate->idx + 1; j < n_bitrates; j++) { 272 if (mask & (1 << j)) { 273 /* Okay, found a suitable rate. Use it. */ 274 rate->idx = j; 275 return; 276 } 277 } 278 279 /* 280 * Uh.. No suitable rate exists. This should not really happen with 281 * sane TX rate mask configurations. However, should someone manage to 282 * configure supported rates and TX rate mask in incompatible way, 283 * allow the frame to be transmitted with whatever the rate control 284 * selected. 285 */ 286 } 287 288 void rate_control_get_rate(struct ieee80211_sub_if_data *sdata, 289 struct sta_info *sta, 290 struct ieee80211_tx_rate_control *txrc) 291 { 292 struct rate_control_ref *ref = sdata->local->rate_ctrl; 293 void *priv_sta = NULL; 294 struct ieee80211_sta *ista = NULL; 295 struct ieee80211_tx_info *info = IEEE80211_SKB_CB(txrc->skb); 296 int i; 297 u32 mask; 298 299 if (sta) { 300 ista = &sta->sta; 301 priv_sta = sta->rate_ctrl_priv; 302 } 303 304 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { 305 info->control.rates[i].idx = -1; 306 info->control.rates[i].flags = 0; 307 info->control.rates[i].count = 1; 308 } 309 310 if (sdata->local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) 311 return; 312 313 ref->ops->get_rate(ref->priv, ista, priv_sta, txrc); 314 315 /* 316 * Try to enforce the rateidx mask the user wanted. skip this if the 317 * default mask (allow all rates) is used to save some processing for 318 * the common case. 319 */ 320 mask = sdata->rc_rateidx_mask[info->band]; 321 if (mask != (1 << txrc->sband->n_bitrates) - 1) { 322 if (sta) { 323 /* Filter out rates that the STA does not support */ 324 mask &= sta->sta.supp_rates[info->band]; 325 } 326 /* 327 * Make sure the rate index selected for each TX rate is 328 * included in the configured mask and change the rate indexes 329 * if needed. 330 */ 331 for (i = 0; i < IEEE80211_TX_MAX_RATES; i++) { 332 /* Rate masking supports only legacy rates for now */ 333 if (info->control.rates[i].flags & IEEE80211_TX_RC_MCS) 334 continue; 335 rate_idx_match_mask(&info->control.rates[i], 336 txrc->sband->n_bitrates, mask); 337 } 338 } 339 340 BUG_ON(info->control.rates[0].idx < 0); 341 } 342 343 struct rate_control_ref *rate_control_get(struct rate_control_ref *ref) 344 { 345 kref_get(&ref->kref); 346 return ref; 347 } 348 349 void rate_control_put(struct rate_control_ref *ref) 350 { 351 kref_put(&ref->kref, rate_control_release); 352 } 353 354 int ieee80211_init_rate_ctrl_alg(struct ieee80211_local *local, 355 const char *name) 356 { 357 struct rate_control_ref *ref, *old; 358 359 ASSERT_RTNL(); 360 361 if (local->open_count) 362 return -EBUSY; 363 364 if (local->hw.flags & IEEE80211_HW_HAS_RATE_CONTROL) { 365 if (WARN_ON(!local->ops->set_rts_threshold)) 366 return -EINVAL; 367 return 0; 368 } 369 370 ref = rate_control_alloc(name, local); 371 if (!ref) { 372 printk(KERN_WARNING "%s: Failed to select rate control " 373 "algorithm\n", wiphy_name(local->hw.wiphy)); 374 return -ENOENT; 375 } 376 377 old = local->rate_ctrl; 378 local->rate_ctrl = ref; 379 if (old) { 380 rate_control_put(old); 381 sta_info_flush(local, NULL); 382 } 383 384 printk(KERN_DEBUG "%s: Selected rate control " 385 "algorithm '%s'\n", wiphy_name(local->hw.wiphy), 386 ref->ops->name); 387 388 return 0; 389 } 390 391 void rate_control_deinitialize(struct ieee80211_local *local) 392 { 393 struct rate_control_ref *ref; 394 395 ref = local->rate_ctrl; 396 397 if (!ref) 398 return; 399 400 local->rate_ctrl = NULL; 401 rate_control_put(ref); 402 } 403 404