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(struct work_struct *work)
  62 {
  63         struct ieee80211softmac_device *mac =
  64                 container_of(work, struct ieee80211softmac_device,
  65                              associnfo.timeout.work);
  66         struct ieee80211softmac_network *n;
  67
  68         mutex_lock(&mac->associnfo.mutex);
  69         /* we might race against ieee80211softmac_handle_assoc_response,
  70          * so make sure only one of us does something */
  71         if (!mac->associnfo.associating)
  72                 goto out;
  73         mac->associnfo.associating = 0;
  74         mac->associnfo.bssvalid = 0;
  75         mac->associnfo.associated = 0;
  76
  77         n = ieee80211softmac_get_network_by_bssid_locked(mac, mac->associnfo.bssid);
  78
  79         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  80         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, n);
  81 out:
  82         mutex_unlock(&mac->associnfo.mutex);
  83 }
  84
  85 void
  86 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac)
  87 {
  88         unsigned long flags;
  89
  90         spin_lock_irqsave(&mac->lock, flags);
  91         if (mac->associnfo.associating)
  92                 cancel_delayed_work(&mac->associnfo.timeout);
  93
  94         netif_carrier_off(mac->dev);
  95
  96         mac->associnfo.associated = 0;
  97         mac->associnfo.bssvalid = 0;
  98         mac->associnfo.associating = 0;
  99         ieee80211softmac_init_bss(mac);
 100         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
 101         spin_unlock_irqrestore(&mac->lock, flags);
 102 }
 103
 104 /* Sends out a disassociation request to the desired AP */
 105 void
 106 ieee80211softmac_send_disassoc_req(struct ieee80211softmac_device *mac, u16 reason)
 107 {
 108         struct ieee80211softmac_network *found;
 109
 110         if (mac->associnfo.bssvalid && mac->associnfo.associated) {
 111                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 112                 if (found)
 113                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
 114         }
 115
 116         ieee80211softmac_disassoc(mac);
 117 }
 118
 119 static inline int
 120 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
 121 {
 122         int idx;
 123         u8 rate;
 124
 125         for (idx = 0; idx < (from_len); idx++) {
 126                 rate = (from)[idx];
 127                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 128                         continue;
 129                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 130                 if (!ieee80211softmac_ratesinfo_rate_supported(&mac->ratesinfo, rate))
 131                         return 0;
 132         }
 133         return 1;
 134 }
 135
 136 static int
 137 network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
 138 {
 139         /* we cannot associate to networks whose name we don't know */
 140         if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
 141                 return 0;
 142         /* do not associate to a network whose BSSBasicRateSet we cannot support */
 143         if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
 144                 return 0;
 145         /* do we really need to check the ex rates? */
 146         if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
 147                 return 0;
 148
 149         /* assume that users know what they're doing ...
 150          * (note we don't let them select a net we're incompatible with) */
 151         if (mac->associnfo.bssfixed) {
 152                 return !memcmp(mac->associnfo.bssid, net->bssid, ETH_ALEN);
 153         }
 154
 155         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 156         if (mac->associnfo.req_essid.len == 0
 157             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 158                 return 1;
 159         if (net->ssid_len != mac->associnfo.req_essid.len)
 160                 return 0;
 161         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 162                 return 1;
 163         return 0;
 164 }
 165
 166 static void
 167 ieee80211softmac_assoc_notify_scan(struct net_device *dev, int event_type, void *context)
 168 {
 169         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 170         ieee80211softmac_assoc_work(&mac->associnfo.work.work);
 171 }
 172
 173 static void
 174 ieee80211softmac_assoc_notify_auth(struct net_device *dev, int event_type, void *context)
 175 {
 176         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 177
 178         switch (event_type) {
 179         case IEEE80211SOFTMAC_EVENT_AUTHENTICATED:
 180                 ieee80211softmac_assoc_work(&mac->associnfo.work.work);
 181                 break;
 182         case IEEE80211SOFTMAC_EVENT_AUTH_FAILED:
 183         case IEEE80211SOFTMAC_EVENT_AUTH_TIMEOUT:
 184                 ieee80211softmac_disassoc(mac);
 185                 break;
 186         }
 187 }
 188
 189 /* This function is called to handle userspace requests (asynchronously) */
 190 void
 191 ieee80211softmac_assoc_work(struct work_struct *work)
 192 {
 193         struct ieee80211softmac_device *mac =
 194                 container_of(work, struct ieee80211softmac_device,
 195                              associnfo.work.work);
 196         struct ieee80211softmac_network *found = NULL;
 197         struct ieee80211_network *net = NULL, *best = NULL;
 198         int bssvalid;
 199         unsigned long flags;
 200
 201         mutex_lock(&mac->associnfo.mutex);
 202
 203         if (!mac->associnfo.associating)
 204                 goto out;
 205
 206         /* ieee80211_disassoc might clear this */
 207         bssvalid = mac->associnfo.bssvalid;
 208
 209         /* meh */
 210         if (mac->associnfo.associated)
 211                 ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 212
 213         /* try to find the requested network in our list, if we found one already */
 214         if (bssvalid || mac->associnfo.bssfixed)
 215                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 216
 217         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 218          * but only if we've scanned at least once (to get a better list of networks to
 219          * select from). If we have not scanned before, the !found logic below will be
 220          * invoked and will scan. */
 221         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 222         {
 223                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 224                                    because it cannot follow the best pointer logic. */
 225                 spin_lock_irqsave(&mac->ieee->lock, flags);
 226                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 227                         /* we're supposed to find the network with
 228                          * the best signal here, as we're asked to join
 229                          * any network with a specific ESSID, and many
 230                          * different ones could have that.
 231                          *
 232                          * I'll for now just go with the reported rssi.
 233                          *
 234                          * We also should take into account the rateset
 235                          * here to find the best BSSID to try.
 236                          */
 237                         if (network_matches_request(mac, net)) {
 238                                 if (!best) {
 239                                         best = net;
 240                                         rssi = best->stats.rssi;
 241                                         continue;
 242                                 }
 243                                 /* we already had a matching network, so
 244                                  * compare their properties to get the
 245                                  * better of the two ... (see above)
 246                                  */
 247                                 if (rssi < net->stats.rssi) {
 248                                         best = net;
 249                                         rssi = best->stats.rssi;
 250                                 }
 251                         }
 252                 }
 253                 /* if we unlock here, we might get interrupted and the `best'
 254                  * pointer could go stale */
 255                 if (best) {
 256                         found = ieee80211softmac_create_network(mac, best);
 257                         /* if found is still NULL, then we got -ENOMEM somewhere */
 258                         if (found)
 259                                 ieee80211softmac_add_network(mac, found);
 260                 }
 261                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 262         }
 263
 264         if (!found) {
 265                 if (mac->associnfo.scan_retry > 0) {
 266                         mac->associnfo.scan_retry--;
 267
 268                         /* We know of no such network. Let's scan.
 269                          * NB: this also happens if we had no memory to copy the network info...
 270                          * Maybe we can hope to have more memory after scanning finishes ;)
 271                          */
 272                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 273                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
 274                         if (ieee80211softmac_start_scan(mac)) {
 275                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 276                                 mac->associnfo.associating = 0;
 277                                 mac->associnfo.associated = 0;
 278                         }
 279                         goto out;
 280                 } else {
 281                         mac->associnfo.associating = 0;
 282                         mac->associnfo.associated = 0;
 283
 284                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 285                         /* reset the retry counter for the next user request since we
 286                          * break out and don't reschedule ourselves after this point. */
 287                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 288                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 289                         goto out;
 290                 }
 291         }
 292
 293         /* reset the retry counter for the next user request since we
 294          * now found a net and will try to associate to it, but not
 295          * schedule this function again. */
 296         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 297         mac->associnfo.bssvalid = 1;
 298         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 299         /* copy the ESSID for displaying it */
 300         mac->associnfo.associate_essid.len = found->essid.len;
 301         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 302
 303         /* we found a network! authenticate (if necessary) and associate to it. */
 304         if (found->authenticating) {
 305                 dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
 306                 if(!mac->associnfo.assoc_wait) {
 307                         mac->associnfo.assoc_wait = 1;
 308                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 309                 }
 310                 goto out;
 311         }
 312         if (!found->authenticated && !found->authenticating) {
 313                 /* This relies on the fact that _auth_req only queues the work,
 314                  * otherwise adding the notification would be racy. */
 315                 if (!ieee80211softmac_auth_req(mac, found)) {
 316                         if(!mac->associnfo.assoc_wait) {
 317                                 dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
 318                                 mac->associnfo.assoc_wait = 1;
 319                                 ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 320                         }
 321                 } else {
 322                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 323                         mac->associnfo.assoc_wait = 0;
 324                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 325                 }
 326                 goto out;
 327         }
 328         /* finally! now we can start associating */
 329         mac->associnfo.assoc_wait = 0;
 330         ieee80211softmac_assoc(mac, found);
 331
 332 out:
 333         mutex_unlock(&mac->associnfo.mutex);
 334 }
 335
 336 /* call this to do whatever is necessary when we're associated */
 337 static void
 338 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 339         struct ieee80211_assoc_response * resp,
 340         struct ieee80211softmac_network *net)
 341 {
 342         u16 cap = le16_to_cpu(resp->capability);
 343         u8 erp_value = net->erp_value;
 344
 345         mac->associnfo.associating = 0;
 346         mac->bssinfo.supported_rates = net->supported_rates;
 347         ieee80211softmac_recalc_txrates(mac);
 348
 349         mac->associnfo.associated = 1;
 350
 351         mac->associnfo.short_preamble_available =
 352                 (cap & WLAN_CAPABILITY_SHORT_PREAMBLE) != 0;
 353         ieee80211softmac_process_erp(mac, erp_value);
 354
 355         if (mac->set_bssid_filter)
 356                 mac->set_bssid_filter(mac->dev, net->bssid);
 357         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 358         netif_carrier_on(mac->dev);
 359
 360         mac->association_id = le16_to_cpup(&resp->aid);
 361 }
 362
 363 /* received frame handling functions */
 364 int
 365 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 366                                        struct ieee80211_assoc_response * resp,
 367                                        struct ieee80211_network * _ieee80211_network)
 368 {
 369         /* NOTE: the network parameter has to be mostly ignored by
 370          *       this code because it is the ieee80211's pointer
 371          *       to the struct, not ours (we made a copy)
 372          */
 373         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 374         u16 status = le16_to_cpup(&resp->status);
 375         struct ieee80211softmac_network *network = NULL;
 376         unsigned long flags;
 377
 378         if (unlikely(!mac->running))
 379                 return -ENODEV;
 380
 381         spin_lock_irqsave(&mac->lock, flags);
 382
 383         if (!mac->associnfo.associating) {
 384                 /* we race against the timeout function, so make sure
 385                  * only one of us can do work */
 386                 spin_unlock_irqrestore(&mac->lock, flags);
 387                 return 0;
 388         }
 389         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 390
 391         /* someone sending us things without us knowing him? Ignore. */
 392         if (!network) {
 393                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 394                 spin_unlock_irqrestore(&mac->lock, flags);
 395                 return 0;
 396         }
 397
 398         /* now that we know it was for us, we can cancel the timeout */
 399         cancel_delayed_work(&mac->associnfo.timeout);
 400
 401         /* if the association response included an ERP IE, update our saved
 402          * copy */
 403         if (_ieee80211_network->flags & NETWORK_HAS_ERP_VALUE)
 404                 network->erp_value = _ieee80211_network->erp_value;
 405
 406         switch (status) {
 407                 case 0:
 408                         dprintk(KERN_INFO PFX "associated!\n");
 409                         ieee80211softmac_associated(mac, resp, network);
 410                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 411                         break;
 412                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 413                         if (!network->auth_desynced_once) {
 414                                 /* there seem to be a few rare cases where our view of
 415                                  * the world is obscured, or buggy APs that don't DEAUTH
 416                                  * us properly. So we handle that, but allow it only once.
 417                                  */
 418                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 419                                 network->authenticated = 0;
 420                                 /* we don't want to do this more than once ... */
 421                                 network->auth_desynced_once = 1;
 422                                 schedule_delayed_work(&mac->associnfo.work, 0);
 423                                 break;
 424                         }
 425                 default:
 426                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 427                         mac->associnfo.associating = 0;
 428                         mac->associnfo.bssvalid = 0;
 429                         mac->associnfo.associated = 0;
 430                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 431         }
 432
 433         spin_unlock_irqrestore(&mac->lock, flags);
 434         return 0;
 435 }
 436
 437 void
 438 ieee80211softmac_try_reassoc(struct ieee80211softmac_device *mac)
 439 {
 440         unsigned long flags;
 441
 442         spin_lock_irqsave(&mac->lock, flags);
 443         mac->associnfo.associating = 1;
 444         schedule_delayed_work(&mac->associnfo.work, 0);
 445         spin_unlock_irqrestore(&mac->lock, flags);
 446 }
 447
 448 int
 449 ieee80211softmac_handle_disassoc(struct net_device * dev,
 450                                  struct ieee80211_disassoc *disassoc)
 451 {
 452         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 453
 454         if (unlikely(!mac->running))
 455                 return -ENODEV;
 456
 457         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 458                 return 0;
 459
 460         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 461                 return 0;
 462
 463         dprintk(KERN_INFO PFX "got disassoc frame\n");
 464         ieee80211softmac_disassoc(mac);
 465
 466         ieee80211softmac_try_reassoc(mac);
 467
 468         return 0;
 469 }
 470
 471 int
 472 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 473                                     struct ieee80211_reassoc_request * resp)
 474 {
 475         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 476         struct ieee80211softmac_network *network;
 477
 478         if (unlikely(!mac->running))
 479                 return -ENODEV;
 480
 481         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 482         if (!network) {
 483                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 484                 return 0;
 485         }
 486         schedule_delayed_work(&mac->associnfo.work, 0);
 487
 488         return 0;
 489 }