err.no Git - linux-2.6/blob - net/ieee80211/softmac/ieee80211softmac_module.c

   1 /*
   2  * Contains some basic softmac functions along with module registration code etc.
   3  *
   4  * Copyright (c) 2005, 2006 Johannes Berg <johannes@sipsolutions.net>
   5  *                          Joseph Jezak <josejx@gentoo.org>
   6  *                          Larry Finger <Larry.Finger@lwfinger.net>
   7  *                          Danny van Dyk <kugelfang@gentoo.org>
   8  *                          Michael Buesch <mbuesch@freenet.de>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of version 2 of the GNU General Public License as
  12  * published by the Free Software Foundation.
  13  *
  14  * This program is distributed in the hope that it will be useful, but WITHOUT
  15  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  16  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  17  * more details.
  18  *
  19  * You should have received a copy of the GNU General Public License
  20  * along with this program; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
  22  *
  23  * The full GNU General Public License is included in this distribution in the
  24  * file called COPYING.
  25  */
  26
  27 #include "ieee80211softmac_priv.h"
  28 #include <linux/sort.h>
  29 #include <linux/etherdevice.h>
  30
  31 struct net_device *alloc_ieee80211softmac(int sizeof_priv)
  32 {
  33         struct ieee80211softmac_device *softmac;
  34         struct net_device *dev;
  35
  36         dev = alloc_ieee80211(sizeof(*softmac) + sizeof_priv);
  37         if (!dev)
  38                 return NULL;
  39         softmac = ieee80211_priv(dev);
  40         softmac->wq = create_freezeable_workqueue("softmac");
  41         if (!softmac->wq) {
  42                 free_ieee80211(dev);
  43                 return NULL;
  44         }
  45
  46         softmac->dev = dev;
  47         softmac->ieee = netdev_priv(dev);
  48         spin_lock_init(&softmac->lock);
  49
  50         softmac->ieee->handle_auth = ieee80211softmac_auth_resp;
  51         softmac->ieee->handle_deauth = ieee80211softmac_deauth_resp;
  52         softmac->ieee->handle_assoc_response = ieee80211softmac_handle_assoc_response;
  53         softmac->ieee->handle_reassoc_request = ieee80211softmac_handle_reassoc_req;
  54         softmac->ieee->handle_disassoc = ieee80211softmac_handle_disassoc;
  55         softmac->ieee->handle_beacon = ieee80211softmac_handle_beacon;
  56         softmac->scaninfo = NULL;
  57
  58         softmac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
  59
  60         /* TODO: initialise all the other callbacks in the ieee struct
  61          *       (once they're written)
  62          */
  63
  64         INIT_LIST_HEAD(&softmac->auth_queue);
  65         INIT_LIST_HEAD(&softmac->network_list);
  66         INIT_LIST_HEAD(&softmac->events);
  67
  68         mutex_init(&softmac->associnfo.mutex);
  69         INIT_DELAYED_WORK(&softmac->associnfo.work, ieee80211softmac_assoc_work);
  70         INIT_DELAYED_WORK(&softmac->associnfo.timeout, ieee80211softmac_assoc_timeout);
  71         softmac->start_scan = ieee80211softmac_start_scan_implementation;
  72         softmac->wait_for_scan = ieee80211softmac_wait_for_scan_implementation;
  73         softmac->stop_scan = ieee80211softmac_stop_scan_implementation;
  74
  75         /* to start with, we can't send anything ... */
  76         netif_carrier_off(dev);
  77
  78         return dev;
  79 }
  80 EXPORT_SYMBOL_GPL(alloc_ieee80211softmac);
  81
  82 /* Clears the pending work queue items, stops all scans, etc. */
  83 void
  84 ieee80211softmac_clear_pending_work(struct ieee80211softmac_device *sm)
  85 {
  86         unsigned long flags;
  87         struct ieee80211softmac_event *eventptr, *eventtmp;
  88         struct ieee80211softmac_auth_queue_item *authptr, *authtmp;
  89         struct ieee80211softmac_network *netptr, *nettmp;
  90
  91         ieee80211softmac_stop_scan(sm);
  92         ieee80211softmac_wait_for_scan(sm);
  93
  94         spin_lock_irqsave(&sm->lock, flags);
  95         sm->running = 0;
  96
  97         /* Free all pending assoc work items */
  98         cancel_delayed_work(&sm->associnfo.work);
  99
 100         /* Free all pending scan work items */
 101         if(sm->scaninfo != NULL)
 102                 cancel_delayed_work(&sm->scaninfo->softmac_scan);
 103
 104         /* Free all pending auth work items */
 105         list_for_each_entry(authptr, &sm->auth_queue, list)
 106                 cancel_delayed_work(&authptr->work);
 107
 108         /* delete all pending event calls and work items */
 109         list_for_each_entry_safe(eventptr, eventtmp, &sm->events, list)
 110                 cancel_delayed_work(&eventptr->work);
 111
 112         spin_unlock_irqrestore(&sm->lock, flags);
 113         flush_workqueue(sm->wq);
 114
 115         /* now we should be save and no longer need locking... */
 116         spin_lock_irqsave(&sm->lock, flags);
 117         /* Free all pending auth work items */
 118         list_for_each_entry_safe(authptr, authtmp, &sm->auth_queue, list) {
 119                 list_del(&authptr->list);
 120                 kfree(authptr);
 121         }
 122
 123         /* delete all pending event calls and work items */
 124         list_for_each_entry_safe(eventptr, eventtmp, &sm->events, list) {
 125                 list_del(&eventptr->list);
 126                 kfree(eventptr);
 127         }
 128
 129         /* Free all networks */
 130         list_for_each_entry_safe(netptr, nettmp, &sm->network_list, list) {
 131                 ieee80211softmac_del_network_locked(sm, netptr);
 132                 if(netptr->challenge != NULL)
 133                         kfree(netptr->challenge);
 134                 kfree(netptr);
 135         }
 136
 137         spin_unlock_irqrestore(&sm->lock, flags);
 138 }
 139 EXPORT_SYMBOL_GPL(ieee80211softmac_clear_pending_work);
 140
 141 void free_ieee80211softmac(struct net_device *dev)
 142 {
 143         struct ieee80211softmac_device *sm = ieee80211_priv(dev);
 144         ieee80211softmac_clear_pending_work(sm);
 145         kfree(sm->scaninfo);
 146         kfree(sm->wpa.IE);
 147         destroy_workqueue(sm->wq);
 148         free_ieee80211(dev);
 149 }
 150 EXPORT_SYMBOL_GPL(free_ieee80211softmac);
 151
 152 static void ieee80211softmac_start_check_rates(struct ieee80211softmac_device *mac)
 153 {
 154         struct ieee80211softmac_ratesinfo *ri = &mac->ratesinfo;
 155         /* I took out the sorting check, we're seperating by modulation now. */
 156         if (ri->count)
 157                 return;
 158         /* otherwise assume we hav'em all! */
 159         if (mac->ieee->modulation & IEEE80211_CCK_MODULATION) {
 160                 ri->rates[ri->count++] = IEEE80211_CCK_RATE_1MB;
 161                 ri->rates[ri->count++] = IEEE80211_CCK_RATE_2MB;
 162                 ri->rates[ri->count++] = IEEE80211_CCK_RATE_5MB;
 163                 ri->rates[ri->count++] = IEEE80211_CCK_RATE_11MB;
 164         }
 165         if (mac->ieee->modulation & IEEE80211_OFDM_MODULATION) {
 166                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_6MB;
 167                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_9MB;
 168                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_12MB;
 169                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_18MB;
 170                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_24MB;
 171                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_36MB;
 172                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_48MB;
 173                 ri->rates[ri->count++] = IEEE80211_OFDM_RATE_54MB;
 174         }
 175 }
 176
 177 int ieee80211softmac_ratesinfo_rate_supported(struct ieee80211softmac_ratesinfo *ri, u8 rate)
 178 {
 179         int search;
 180         u8 search_rate;
 181
 182         for (search = 0; search < ri->count; search++) {
 183                 search_rate = ri->rates[search];
 184                 search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 185                 if (rate == search_rate)
 186                         return 1;
 187         }
 188
 189         return 0;
 190 }
 191
 192 u8 ieee80211softmac_highest_supported_rate(struct ieee80211softmac_device *mac,
 193         struct ieee80211softmac_ratesinfo *ri, int basic_only)
 194 {
 195         u8 user_rate = mac->txrates.user_rate;
 196         int i;
 197
 198         if (ri->count == 0)
 199                 return IEEE80211_CCK_RATE_1MB;
 200
 201         for (i = ri->count - 1; i >= 0; i--) {
 202                 u8 rate = ri->rates[i];
 203                 if (basic_only && !(rate & IEEE80211_BASIC_RATE_MASK))
 204                         continue;
 205                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 206                 if (rate > user_rate)
 207                         continue;
 208                 if (ieee80211softmac_ratesinfo_rate_supported(&mac->ratesinfo, rate))
 209                         return rate;
 210         }
 211
 212         /* If we haven't found a suitable rate by now, just trust the user */
 213         return user_rate;
 214 }
 215 EXPORT_SYMBOL_GPL(ieee80211softmac_highest_supported_rate);
 216
 217 void ieee80211softmac_process_erp(struct ieee80211softmac_device *mac,
 218         u8 erp_value)
 219 {
 220         int use_protection;
 221         int short_preamble;
 222         u32 changes = 0;
 223
 224         /* Barker preamble mode */
 225         short_preamble = ((erp_value & WLAN_ERP_BARKER_PREAMBLE) == 0
 226                           && mac->associnfo.short_preamble_available) ? 1 : 0;
 227
 228         /* Protection needed? */
 229         use_protection = (erp_value & WLAN_ERP_USE_PROTECTION) != 0;
 230
 231         if (mac->bssinfo.short_preamble != short_preamble) {
 232                 changes |= IEEE80211SOFTMAC_BSSINFOCHG_SHORT_PREAMBLE;
 233                 mac->bssinfo.short_preamble = short_preamble;
 234         }
 235
 236         if (mac->bssinfo.use_protection != use_protection) {
 237                 changes |= IEEE80211SOFTMAC_BSSINFOCHG_PROTECTION;
 238                 mac->bssinfo.use_protection = use_protection;
 239         }
 240
 241         if (mac->bssinfo_change && changes)
 242                 mac->bssinfo_change(mac->dev, changes);
 243 }
 244
 245 void ieee80211softmac_recalc_txrates(struct ieee80211softmac_device *mac)
 246 {
 247         struct ieee80211softmac_txrates *txrates = &mac->txrates;
 248         u32 change = 0;
 249
 250         change |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT;
 251         txrates->default_rate = ieee80211softmac_highest_supported_rate(mac, &mac->bssinfo.supported_rates, 0);
 252
 253         change |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT_FBACK;
 254         txrates->default_fallback = lower_rate(mac, txrates->default_rate);
 255
 256         change |= IEEE80211SOFTMAC_TXRATECHG_MCAST;
 257         txrates->mcast_rate = ieee80211softmac_highest_supported_rate(mac, &mac->bssinfo.supported_rates, 1);
 258
 259         if (mac->txrates_change)
 260                 mac->txrates_change(mac->dev, change);
 261
 262 }
 263
 264 void ieee80211softmac_init_bss(struct ieee80211softmac_device *mac)
 265 {
 266         struct ieee80211_device *ieee = mac->ieee;
 267         u32 change = 0;
 268         struct ieee80211softmac_txrates *txrates = &mac->txrates;
 269         struct ieee80211softmac_bss_info *bssinfo = &mac->bssinfo;
 270
 271         /* TODO: We need some kind of state machine to lower the default rates
 272          *       if we loose too many packets.
 273          */
 274         /* Change the default txrate to the highest possible value.
 275          * The txrate machine will lower it, if it is too high.
 276          */
 277         if (ieee->modulation & IEEE80211_OFDM_MODULATION)
 278                 txrates->user_rate = IEEE80211_OFDM_RATE_24MB;
 279         else
 280                 txrates->user_rate = IEEE80211_CCK_RATE_11MB;
 281
 282         txrates->default_rate = IEEE80211_CCK_RATE_1MB;
 283         change |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT;
 284
 285         txrates->default_fallback = IEEE80211_CCK_RATE_1MB;
 286         change |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT_FBACK;
 287
 288         txrates->mcast_rate = IEEE80211_CCK_RATE_1MB;
 289         change |= IEEE80211SOFTMAC_TXRATECHG_MCAST;
 290
 291         txrates->mgt_mcast_rate = IEEE80211_CCK_RATE_1MB;
 292         change |= IEEE80211SOFTMAC_TXRATECHG_MGT_MCAST;
 293
 294         if (mac->txrates_change)
 295                 mac->txrates_change(mac->dev, change);
 296
 297         change = 0;
 298
 299         bssinfo->supported_rates.count = 0;
 300         memset(bssinfo->supported_rates.rates, 0,
 301                 sizeof(bssinfo->supported_rates.rates));
 302         change |= IEEE80211SOFTMAC_BSSINFOCHG_RATES;
 303
 304         bssinfo->short_preamble = 0;
 305         change |= IEEE80211SOFTMAC_BSSINFOCHG_SHORT_PREAMBLE;
 306
 307         bssinfo->use_protection = 0;
 308         change |= IEEE80211SOFTMAC_BSSINFOCHG_PROTECTION;
 309
 310         if (mac->bssinfo_change)
 311                 mac->bssinfo_change(mac->dev, change);
 312
 313         mac->running = 1;
 314 }
 315
 316 void ieee80211softmac_start(struct net_device *dev)
 317 {
 318         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 319
 320         ieee80211softmac_start_check_rates(mac);
 321         ieee80211softmac_init_bss(mac);
 322 }
 323 EXPORT_SYMBOL_GPL(ieee80211softmac_start);
 324
 325 void ieee80211softmac_stop(struct net_device *dev)
 326 {
 327         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 328
 329         ieee80211softmac_clear_pending_work(mac);
 330 }
 331 EXPORT_SYMBOL_GPL(ieee80211softmac_stop);
 332
 333 void ieee80211softmac_set_rates(struct net_device *dev, u8 count, u8 *rates)
 334 {
 335         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 336         unsigned long flags;
 337
 338         spin_lock_irqsave(&mac->lock, flags);
 339         memcpy(mac->ratesinfo.rates, rates, count);
 340         mac->ratesinfo.count = count;
 341         spin_unlock_irqrestore(&mac->lock, flags);
 342 }
 343 EXPORT_SYMBOL_GPL(ieee80211softmac_set_rates);
 344
 345 static u8 raise_rate(struct ieee80211softmac_device *mac, u8 rate)
 346 {
 347         int i;
 348         struct ieee80211softmac_ratesinfo *ri = &mac->ratesinfo;
 349
 350         for (i=0; i<ri->count-1; i++) {
 351                 if (ri->rates[i] == rate)
 352                         return ri->rates[i+1];
 353         }
 354         /* I guess we can't go any higher... */
 355         return ri->rates[ri->count];
 356 }
 357
 358 u8 ieee80211softmac_lower_rate_delta(struct ieee80211softmac_device *mac, u8 rate, int delta)
 359 {
 360         int i;
 361         struct ieee80211softmac_ratesinfo *ri = &mac->ratesinfo;
 362
 363         for (i=delta; i<ri->count; i++) {
 364                 if (ri->rates[i] == rate)
 365                         return ri->rates[i-delta];
 366         }
 367         /* I guess we can't go any lower... */
 368         return ri->rates[0];
 369 }
 370
 371 static void ieee80211softmac_add_txrates_badness(struct ieee80211softmac_device *mac,
 372                                                  int amount)
 373 {
 374         u8 default_rate = mac->txrates.default_rate;
 375         u8 default_fallback = mac->txrates.default_fallback;
 376         u32 changes = 0;
 377
 378         //TODO: This is highly experimental code.
 379         //      Maybe the dynamic rate selection does not work
 380         //      and it has to be removed again.
 381
 382 printk("badness %d\n", mac->txrate_badness);
 383         mac->txrate_badness += amount;
 384         if (mac->txrate_badness <= -1000) {
 385                 /* Very small badness. Try a faster bitrate. */
 386                 default_rate = raise_rate(mac, default_rate);
 387                 changes |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT;
 388                 default_fallback = get_fallback_rate(mac, default_rate);
 389                 changes |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT_FBACK;
 390                 mac->txrate_badness = 0;
 391 printk("Bitrate raised to %u\n", default_rate);
 392         } else if (mac->txrate_badness >= 10000) {
 393                 /* Very high badness. Try a slower bitrate. */
 394                 default_rate = lower_rate(mac, default_rate);
 395                 changes |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT;
 396                 default_fallback = get_fallback_rate(mac, default_rate);
 397                 changes |= IEEE80211SOFTMAC_TXRATECHG_DEFAULT_FBACK;
 398                 mac->txrate_badness = 0;
 399 printk("Bitrate lowered to %u\n", default_rate);
 400         }
 401
 402         mac->txrates.default_rate = default_rate;
 403         mac->txrates.default_fallback = default_fallback;
 404
 405         if (changes && mac->txrates_change)
 406                 mac->txrates_change(mac->dev, changes);
 407 }
 408
 409 void ieee80211softmac_fragment_lost(struct net_device *dev,
 410                                     u16 wl_seq)
 411 {
 412         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 413         unsigned long flags;
 414
 415         spin_lock_irqsave(&mac->lock, flags);
 416         ieee80211softmac_add_txrates_badness(mac, 1000);
 417         //TODO
 418
 419         spin_unlock_irqrestore(&mac->lock, flags);
 420 }
 421 EXPORT_SYMBOL_GPL(ieee80211softmac_fragment_lost);
 422
 423 static int rate_cmp(const void *a_, const void *b_) {
 424         u8 *a, *b;
 425         a = (u8*)a_;
 426         b = (u8*)b_;
 427         return ((*a & ~IEEE80211_BASIC_RATE_MASK) - (*b & ~IEEE80211_BASIC_RATE_MASK));
 428 }
 429
 430 /* Allocate a softmac network struct and fill it from a network */
 431 struct ieee80211softmac_network *
 432 ieee80211softmac_create_network(struct ieee80211softmac_device *mac,
 433         struct ieee80211_network *net)
 434 {
 435         struct ieee80211softmac_network *softnet;
 436         softnet = kzalloc(sizeof(struct ieee80211softmac_network), GFP_ATOMIC);
 437         if(softnet == NULL)
 438                 return NULL;
 439         memcpy(softnet->bssid, net->bssid, ETH_ALEN);
 440         softnet->channel = net->channel;
 441         softnet->essid.len = net->ssid_len;
 442         memcpy(softnet->essid.data, net->ssid, softnet->essid.len);
 443
 444         /* copy rates over */
 445         softnet->supported_rates.count = net->rates_len;
 446         memcpy(&softnet->supported_rates.rates[0], net->rates, net->rates_len);
 447         memcpy(&softnet->supported_rates.rates[softnet->supported_rates.count], net->rates_ex, net->rates_ex_len);
 448         softnet->supported_rates.count += net->rates_ex_len;
 449         sort(softnet->supported_rates.rates, softnet->supported_rates.count, sizeof(softnet->supported_rates.rates[0]), rate_cmp, NULL);
 450
 451         /* we save the ERP value because it is needed at association time, and
 452          * many AP's do not include an ERP IE in the association response. */
 453         softnet->erp_value = net->erp_value;
 454
 455         softnet->capabilities = net->capability;
 456         return softnet;
 457 }
 458
 459
 460 /* Add a network to the list, while locked */
 461 void
 462 ieee80211softmac_add_network_locked(struct ieee80211softmac_device *mac,
 463         struct ieee80211softmac_network *add_net)
 464 {
 465         struct ieee80211softmac_network *softmac_net;
 466
 467         list_for_each_entry(softmac_net, &mac->network_list, list) {
 468                 if(!memcmp(softmac_net->bssid, add_net->bssid, ETH_ALEN))
 469                         return;
 470         }
 471         list_add(&(add_net->list), &mac->network_list);
 472 }
 473
 474 /* Add a network to the list, with locking */
 475 void
 476 ieee80211softmac_add_network(struct ieee80211softmac_device *mac,
 477         struct ieee80211softmac_network *add_net)
 478 {
 479         unsigned long flags;
 480         spin_lock_irqsave(&mac->lock, flags);
 481         ieee80211softmac_add_network_locked(mac, add_net);
 482         spin_unlock_irqrestore(&mac->lock, flags);
 483 }
 484
 485
 486 /* Delete a network from the list, while locked*/
 487 void
 488 ieee80211softmac_del_network_locked(struct ieee80211softmac_device *mac,
 489         struct ieee80211softmac_network *del_net)
 490 {
 491         list_del(&(del_net->list));
 492 }
 493
 494 /* Delete a network from the list with locking */
 495 void
 496 ieee80211softmac_del_network(struct ieee80211softmac_device *mac,
 497         struct ieee80211softmac_network *del_net)
 498 {
 499         unsigned long flags;
 500         spin_lock_irqsave(&mac->lock, flags);
 501         ieee80211softmac_del_network_locked(mac, del_net);
 502         spin_unlock_irqrestore(&mac->lock, flags);
 503 }
 504
 505 /* Get a network from the list by MAC while locked */
 506 struct ieee80211softmac_network *
 507 ieee80211softmac_get_network_by_bssid_locked(struct ieee80211softmac_device *mac,
 508         u8 *bssid)
 509 {
 510         struct ieee80211softmac_network *softmac_net;
 511
 512         list_for_each_entry(softmac_net, &mac->network_list, list) {
 513                 if(!memcmp(softmac_net->bssid, bssid, ETH_ALEN))
 514                         return softmac_net;
 515         }
 516         return NULL;
 517 }
 518
 519 /* Get a network from the list by BSSID with locking */
 520 struct ieee80211softmac_network *
 521 ieee80211softmac_get_network_by_bssid(struct ieee80211softmac_device *mac,
 522         u8 *bssid)
 523 {
 524         unsigned long flags;
 525         struct ieee80211softmac_network *softmac_net;
 526
 527         spin_lock_irqsave(&mac->lock, flags);
 528         softmac_net = ieee80211softmac_get_network_by_bssid_locked(mac, bssid);
 529         spin_unlock_irqrestore(&mac->lock, flags);
 530         return softmac_net;
 531 }
 532
 533 /* Get a network from the list by ESSID while locked */
 534 struct ieee80211softmac_network *
 535 ieee80211softmac_get_network_by_essid_locked(struct ieee80211softmac_device *mac,
 536         struct ieee80211softmac_essid *essid)
 537 {
 538         struct ieee80211softmac_network *softmac_net;
 539
 540         list_for_each_entry(softmac_net, &mac->network_list, list) {
 541                 if (softmac_net->essid.len == essid->len &&
 542                         !memcmp(softmac_net->essid.data, essid->data, essid->len))
 543                         return softmac_net;
 544         }
 545         return NULL;
 546 }
 547
 548 /* Get a network from the list by ESSID with locking */
 549 struct ieee80211softmac_network *
 550 ieee80211softmac_get_network_by_essid(struct ieee80211softmac_device *mac,
 551         struct ieee80211softmac_essid *essid)
 552 {
 553         unsigned long flags;
 554         struct ieee80211softmac_network *softmac_net = NULL;
 555
 556         spin_lock_irqsave(&mac->lock, flags);
 557         softmac_net = ieee80211softmac_get_network_by_essid_locked(mac, essid);
 558         spin_unlock_irqrestore(&mac->lock, flags);
 559         return softmac_net;
 560 }
 561
 562 MODULE_LICENSE("GPL");
 563 MODULE_AUTHOR("Johannes Berg");
 564 MODULE_AUTHOR("Joseph Jezak");
 565 MODULE_AUTHOR("Larry Finger");
 566 MODULE_AUTHOR("Danny van Dyk");
 567 MODULE_AUTHOR("Michael Buesch");
 568 MODULE_DESCRIPTION("802.11 software MAC");