net/ieee80211/softmac/ieee80211softmac_assoc.c

   1 /*
   2  * This file contains the softmac's association logic.
   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
  29 /*
  30  * Overview
  31  *
  32  * Before you can associate, you have to authenticate.
  33  *
  34  */
  35
  36 /* Sends out an association request to the desired AP */
  37 static void
  38 ieee80211softmac_assoc(struct ieee80211softmac_device *mac, struct ieee80211softmac_network *net)
  39 {
  40         unsigned long flags;
  41
  42         /* Switch to correct channel for this network */
  43         mac->set_channel(mac->dev, net->channel);
  44
  45         /* Send association request */
  46         ieee80211softmac_send_mgt_frame(mac, net, IEEE80211_STYPE_ASSOC_REQ, 0);
  47
  48         dprintk(KERN_INFO PFX "sent association request!\n");
  49
  50         spin_lock_irqsave(&mac->lock, flags);
  51         mac->associnfo.associated = 0; /* just to make sure */
  52
  53         /* Set a timer for timeout */
  54         /* FIXME: make timeout configurable */
  55         if (likely(mac->running))
  56                 schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
  57         spin_unlock_irqrestore(&mac->lock, flags);
  58 }
  59
  60 void
  61 ieee80211softmac_assoc_timeout(void *d)
  62 {
  63         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
  64         struct ieee80211softmac_network *n;
  65
  66         mutex_lock(&mac->associnfo.mutex);
  67         /* we might race against ieee80211softmac_handle_assoc_response,
  68          * so make sure only one of us does something */
  69         if (!mac->associnfo.associating)
  70                 goto out;
  71         mac->associnfo.associating = 0;
  72         mac->associnfo.bssvalid = 0;
  73         mac->associnfo.associated = 0;
  74
  75         n = ieee80211softmac_get_network_by_bssid_locked(mac, mac->associnfo.bssid);
  76
  77         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  78         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, n);
  79 out:
  80         mutex_unlock(&mac->associnfo.mutex);
  81 }
  82
  83 void
  84 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac)
  85 {
  86         unsigned long flags;
  87
  88         spin_lock_irqsave(&mac->lock, flags);
  89         if (mac->associnfo.associating)
  90                 cancel_delayed_work(&mac->associnfo.timeout);
  91
  92         netif_carrier_off(mac->dev);
  93
  94         mac->associnfo.associated = 0;
  95         mac->associnfo.bssvalid = 0;
  96         mac->associnfo.associating = 0;
  97         ieee80211softmac_init_bss(mac);
  98         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
  99         spin_unlock_irqrestore(&mac->lock, flags);
 100 }
 101
 102 /* Sends out a disassociation request to the desired AP */
 103 void
 104 ieee80211softmac_send_disassoc_req(struct ieee80211softmac_device *mac, u16 reason)
 105 {
 106         struct ieee80211softmac_network *found;
 107
 108         if (mac->associnfo.bssvalid && mac->associnfo.associated) {
 109                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 110                 if (found)
 111                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
 112         }
 113
 114         ieee80211softmac_disassoc(mac);
 115 }
 116
 117 static inline int
 118 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
 119 {
 120         int idx;
 121         u8 rate;
 122
 123         for (idx = 0; idx < (from_len); idx++) {
 124                 rate = (from)[idx];
 125                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 126                         continue;
 127                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 128                 if (!ieee80211softmac_ratesinfo_rate_supported(&mac->ratesinfo, rate))
 129                         return 0;
 130         }
 131         return 1;
 132 }
 133
 134 static int
 135 network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
 136 {
 137         /* we cannot associate to networks whose name we don't know */
 138         if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
 139                 return 0;
 140         /* do not associate to a network whose BSSBasicRateSet we cannot support */
 141         if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
 142                 return 0;
 143         /* do we really need to check the ex rates? */
 144         if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
 145                 return 0;
 146
 147         /* assume that users know what they're doing ...
 148          * (note we don't let them select a net we're incompatible with) */
 149         if (mac->associnfo.bssfixed) {
 150                 return !memcmp(mac->associnfo.bssid, net->bssid, ETH_ALEN);
 151         }
 152
 153         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 154         if (mac->associnfo.req_essid.len == 0
 155             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 156                 return 1;
 157         if (net->ssid_len != mac->associnfo.req_essid.len)
 158                 return 0;
 159         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 160                 return 1;
 161         return 0;
 162 }
 163
 164 static void
 165 ieee80211softmac_assoc_notify_scan(struct net_device *dev, int event_type, void *context)
 166 {
 167         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 168         ieee80211softmac_assoc_work((void*)mac);
 169 }
 170
 171 static void
 172 ieee80211softmac_assoc_notify_auth(struct net_device *dev, int event_type, void *context)
 173 {
 174         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 175
 176         switch (event_type) {
 177         case IEEE80211SOFTMAC_EVENT_AUTHENTICATED:
 178                 ieee80211softmac_assoc_work((void*)mac);
 179                 break;
 180         case IEEE80211SOFTMAC_EVENT_AUTH_FAILED:
 181         case IEEE80211SOFTMAC_EVENT_AUTH_TIMEOUT:
 182                 ieee80211softmac_disassoc(mac);
 183                 break;
 184         }
 185 }
 186
 187 /* This function is called to handle userspace requests (asynchronously) */
 188 void
 189 ieee80211softmac_assoc_work(void *d)
 190 {
 191         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 192         struct ieee80211softmac_network *found = NULL;
 193         struct ieee80211_network *net = NULL, *best = NULL;
 194         int bssvalid;
 195         unsigned long flags;
 196
 197         mutex_lock(&mac->associnfo.mutex);
 198
 199         if (!mac->associnfo.associating)
 200                 goto out;
 201
 202         /* ieee80211_disassoc might clear this */
 203         bssvalid = mac->associnfo.bssvalid;
 204
 205         /* meh */
 206         if (mac->associnfo.associated)
 207                 ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 208
 209         /* try to find the requested network in our list, if we found one already */
 210         if (bssvalid || mac->associnfo.bssfixed)
 211                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 212
 213         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 214          * but only if we've scanned at least once (to get a better list of networks to
 215          * select from). If we have not scanned before, the !found logic below will be
 216          * invoked and will scan. */
 217         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 218         {
 219                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 220                                    because it cannot follow the best pointer logic. */
 221                 spin_lock_irqsave(&mac->ieee->lock, flags);
 222                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 223                         /* we're supposed to find the network with
 224                          * the best signal here, as we're asked to join
 225                          * any network with a specific ESSID, and many
 226                          * different ones could have that.
 227                          *
 228                          * I'll for now just go with the reported rssi.
 229                          *
 230                          * We also should take into account the rateset
 231                          * here to find the best BSSID to try.
 232                          */
 233                         if (network_matches_request(mac, net)) {
 234                                 if (!best) {
 235                                         best = net;
 236                                         rssi = best->stats.rssi;
 237                                         continue;
 238                                 }
 239                                 /* we already had a matching network, so
 240                                  * compare their properties to get the
 241                                  * better of the two ... (see above)
 242                                  */
 243                                 if (rssi < net->stats.rssi) {
 244                                         best = net;
 245                                         rssi = best->stats.rssi;
 246                                 }
 247                         }
 248                 }
 249                 /* if we unlock here, we might get interrupted and the `best'
 250                  * pointer could go stale */
 251                 if (best) {
 252                         found = ieee80211softmac_create_network(mac, best);
 253                         /* if found is still NULL, then we got -ENOMEM somewhere */
 254                         if (found)
 255                                 ieee80211softmac_add_network(mac, found);
 256                 }
 257                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 258         }
 259
 260         if (!found) {
 261                 if (mac->associnfo.scan_retry > 0) {
 262                         mac->associnfo.scan_retry--;
 263
 264                         /* We know of no such network. Let's scan.
 265                          * NB: this also happens if we had no memory to copy the network info...
 266                          * Maybe we can hope to have more memory after scanning finishes ;)
 267                          */
 268                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 269                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
 270                         if (ieee80211softmac_start_scan(mac))
 271                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 272                         goto out;
 273                 } else {
 274                         mac->associnfo.associating = 0;
 275                         mac->associnfo.associated = 0;
 276
 277                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 278                         /* reset the retry counter for the next user request since we
 279                          * break out and don't reschedule ourselves after this point. */
 280                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 281                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 282                         goto out;
 283                 }
 284         }
 285
 286         /* reset the retry counter for the next user request since we
 287          * now found a net and will try to associate to it, but not
 288          * schedule this function again. */
 289         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 290         mac->associnfo.bssvalid = 1;
 291         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 292         /* copy the ESSID for displaying it */
 293         mac->associnfo.associate_essid.len = found->essid.len;
 294         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 295
 296         /* we found a network! authenticate (if necessary) and associate to it. */
 297         if (found->authenticating) {
 298                 dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
 299                 if(!mac->associnfo.assoc_wait) {
 300                         mac->associnfo.assoc_wait = 1;
 301                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 302                 }
 303                 goto out;
 304         }
 305         if (!found->authenticated && !found->authenticating) {
 306                 /* This relies on the fact that _auth_req only queues the work,
 307                  * otherwise adding the notification would be racy. */
 308                 if (!ieee80211softmac_auth_req(mac, found)) {
 309                         if(!mac->associnfo.assoc_wait) {
 310                                 dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
 311                                 mac->associnfo.assoc_wait = 1;
 312                                 ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 313                         }
 314                 } else {
 315                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 316                         mac->associnfo.assoc_wait = 0;
 317                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 318                 }
 319                 goto out;
 320         }
 321         /* finally! now we can start associating */
 322         mac->associnfo.assoc_wait = 0;
 323         ieee80211softmac_assoc(mac, found);
 324
 325 out:
 326         mutex_unlock(&mac->associnfo.mutex);
 327 }
 328
 329 /* call this to do whatever is necessary when we're associated */
 330 static void
 331 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 332         struct ieee80211_assoc_response * resp,
 333         struct ieee80211softmac_network *net)
 334 {
 335         u16 cap = le16_to_cpu(resp->capability);
 336         u8 erp_value = net->erp_value;
 337
 338         mac->associnfo.associating = 0;
 339         mac->bssinfo.supported_rates = net->supported_rates;
 340         ieee80211softmac_recalc_txrates(mac);
 341
 342         mac->associnfo.associated = 1;
 343
 344         mac->associnfo.short_preamble_available =
 345                 (cap & WLAN_CAPABILITY_SHORT_PREAMBLE) != 0;
 346         ieee80211softmac_process_erp(mac, erp_value);
 347
 348         if (mac->set_bssid_filter)
 349                 mac->set_bssid_filter(mac->dev, net->bssid);
 350         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 351         netif_carrier_on(mac->dev);
 352
 353         mac->association_id = le16_to_cpup(&resp->aid);
 354 }
 355
 356 /* received frame handling functions */
 357 int
 358 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 359                                        struct ieee80211_assoc_response * resp,
 360                                        struct ieee80211_network * _ieee80211_network)
 361 {
 362         /* NOTE: the network parameter has to be mostly ignored by
 363          *       this code because it is the ieee80211's pointer
 364          *       to the struct, not ours (we made a copy)
 365          */
 366         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 367         u16 status = le16_to_cpup(&resp->status);
 368         struct ieee80211softmac_network *network = NULL;
 369         unsigned long flags;
 370
 371         if (unlikely(!mac->running))
 372                 return -ENODEV;
 373
 374         spin_lock_irqsave(&mac->lock, flags);
 375
 376         if (!mac->associnfo.associating) {
 377                 /* we race against the timeout function, so make sure
 378                  * only one of us can do work */
 379                 spin_unlock_irqrestore(&mac->lock, flags);
 380                 return 0;
 381         }
 382         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 383
 384         /* someone sending us things without us knowing him? Ignore. */
 385         if (!network) {
 386                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 387                 spin_unlock_irqrestore(&mac->lock, flags);
 388                 return 0;
 389         }
 390
 391         /* now that we know it was for us, we can cancel the timeout */
 392         cancel_delayed_work(&mac->associnfo.timeout);
 393
 394         /* if the association response included an ERP IE, update our saved
 395          * copy */
 396         if (_ieee80211_network->flags & NETWORK_HAS_ERP_VALUE)
 397                 network->erp_value = _ieee80211_network->erp_value;
 398
 399         switch (status) {
 400                 case 0:
 401                         dprintk(KERN_INFO PFX "associated!\n");
 402                         ieee80211softmac_associated(mac, resp, network);
 403                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 404                         break;
 405                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 406                         if (!network->auth_desynced_once) {
 407                                 /* there seem to be a few rare cases where our view of
 408                                  * the world is obscured, or buggy APs that don't DEAUTH
 409                                  * us properly. So we handle that, but allow it only once.
 410                                  */
 411                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 412                                 network->authenticated = 0;
 413                                 /* we don't want to do this more than once ... */
 414                                 network->auth_desynced_once = 1;
 415                                 schedule_work(&mac->associnfo.work);
 416                                 break;
 417                         }
 418                 default:
 419                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 420                         mac->associnfo.associating = 0;
 421                         mac->associnfo.bssvalid = 0;
 422                         mac->associnfo.associated = 0;
 423                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 424         }
 425
 426         spin_unlock_irqrestore(&mac->lock, flags);
 427         return 0;
 428 }
 429
 430 int
 431 ieee80211softmac_handle_disassoc(struct net_device * dev,
 432                                  struct ieee80211_disassoc *disassoc)
 433 {
 434         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 435
 436         if (unlikely(!mac->running))
 437                 return -ENODEV;
 438
 439         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 440                 return 0;
 441
 442         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 443                 return 0;
 444
 445         dprintk(KERN_INFO PFX "got disassoc frame\n");
 446         ieee80211softmac_disassoc(mac);
 447
 448         /* try to reassociate */
 449         schedule_work(&mac->associnfo.work);
 450
 451         return 0;
 452 }
 453
 454 int
 455 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 456                                     struct ieee80211_reassoc_request * resp)
 457 {
 458         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 459         struct ieee80211softmac_network *network;
 460
 461         if (unlikely(!mac->running))
 462                 return -ENODEV;
 463
 464         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 465         if (!network) {
 466                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 467                 return 0;
 468         }
 469         schedule_work(&mac->associnfo.work);
 470
 471         return 0;
 472 }