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->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         unsigned long flags;
  65
  66         spin_lock_irqsave(&mac->lock, flags);
  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                 spin_unlock_irqrestore(&mac->lock, flags);
  71                 return;
  72         }
  73         mac->associnfo.associating = 0;
  74         mac->associnfo.bssvalid = 0;
  75         mac->associated = 0;
  76         spin_unlock_irqrestore(&mac->lock, flags);
  77
  78         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  79         /* FIXME: we need to know the network here. that requires a bit of restructuring */
  80         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
  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->associated = 0;
  95         mac->associnfo.bssvalid = 0;
  96         mac->associnfo.associating = 0;
  97         ieee80211softmac_init_txrates(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->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         /* ieee80211_disassoc might clear this */
 198         bssvalid = mac->associnfo.bssvalid;
 199
 200         /* meh */
 201         if (mac->associated)
 202                 ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 203
 204         spin_lock_irqsave(&mac->lock, flags);
 205         mac->associnfo.associating = 1;
 206         spin_unlock_irqrestore(&mac->lock, flags);
 207
 208         /* try to find the requested network in our list, if we found one already */
 209         if (bssvalid || mac->associnfo.bssfixed)
 210                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 211
 212         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 213          * but only if we've scanned at least once (to get a better list of networks to
 214          * select from). If we have not scanned before, the !found logic below will be
 215          * invoked and will scan. */
 216         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 217         {
 218                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 219                                    because it cannot follow the best pointer logic. */
 220                 spin_lock_irqsave(&mac->ieee->lock, flags);
 221                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 222                         /* we're supposed to find the network with
 223                          * the best signal here, as we're asked to join
 224                          * any network with a specific ESSID, and many
 225                          * different ones could have that.
 226                          *
 227                          * I'll for now just go with the reported rssi.
 228                          *
 229                          * We also should take into account the rateset
 230                          * here to find the best BSSID to try.
 231                          */
 232                         if (network_matches_request(mac, net)) {
 233                                 if (!best) {
 234                                         best = net;
 235                                         rssi = best->stats.rssi;
 236                                         continue;
 237                                 }
 238                                 /* we already had a matching network, so
 239                                  * compare their properties to get the
 240                                  * better of the two ... (see above)
 241                                  */
 242                                 if (rssi < net->stats.rssi) {
 243                                         best = net;
 244                                         rssi = best->stats.rssi;
 245                                 }
 246                         }
 247                 }
 248                 /* if we unlock here, we might get interrupted and the `best'
 249                  * pointer could go stale */
 250                 if (best) {
 251                         found = ieee80211softmac_create_network(mac, best);
 252                         /* if found is still NULL, then we got -ENOMEM somewhere */
 253                         if (found)
 254                                 ieee80211softmac_add_network(mac, found);
 255                 }
 256                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 257         }
 258
 259         if (!found) {
 260                 if (mac->associnfo.scan_retry > 0) {
 261                         spin_lock_irqsave(&mac->lock, flags);
 262                         mac->associnfo.scan_retry--;
 263                         spin_unlock_irqrestore(&mac->lock, flags);
 264
 265                         /* We know of no such network. Let's scan.
 266                          * NB: this also happens if we had no memory to copy the network info...
 267                          * Maybe we can hope to have more memory after scanning finishes ;)
 268                          */
 269                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 270                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
 271                         if (ieee80211softmac_start_scan(mac))
 272                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 273                         return;
 274                 } else {
 275                         spin_lock_irqsave(&mac->lock, flags);
 276                         mac->associnfo.associating = 0;
 277                         mac->associated = 0;
 278                         spin_unlock_irqrestore(&mac->lock, flags);
 279
 280                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 281                         /* reset the retry counter for the next user request since we
 282                          * break out and don't reschedule ourselves after this point. */
 283                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 284                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 285                         return;
 286                 }
 287         }
 288
 289         /* reset the retry counter for the next user request since we
 290          * now found a net and will try to associate to it, but not
 291          * schedule this function again. */
 292         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 293         mac->associnfo.bssvalid = 1;
 294         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 295         /* copy the ESSID for displaying it */
 296         mac->associnfo.associate_essid.len = found->essid.len;
 297         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 298
 299         /* we found a network! authenticate (if necessary) and associate to it. */
 300         if (found->authenticating) {
 301                 dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
 302                 if(!mac->associnfo.assoc_wait) {
 303                         mac->associnfo.assoc_wait = 1;
 304                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 305                 }
 306                 return;
 307         }
 308         if (!found->authenticated && !found->authenticating) {
 309                 /* This relies on the fact that _auth_req only queues the work,
 310                  * otherwise adding the notification would be racy. */
 311                 if (!ieee80211softmac_auth_req(mac, found)) {
 312                         if(!mac->associnfo.assoc_wait) {
 313                                 dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
 314                                 mac->associnfo.assoc_wait = 1;
 315                                 ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 316                         }
 317                 } else {
 318                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 319                         mac->associnfo.assoc_wait = 0;
 320                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 321                 }
 322                 return;
 323         }
 324         /* finally! now we can start associating */
 325         mac->associnfo.assoc_wait = 0;
 326         ieee80211softmac_assoc(mac, found);
 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         mac->associnfo.associating = 0;
 336         mac->associnfo.supported_rates = net->supported_rates;
 337         ieee80211softmac_recalc_txrates(mac);
 338
 339         mac->associated = 1;
 340         if (mac->set_bssid_filter)
 341                 mac->set_bssid_filter(mac->dev, net->bssid);
 342         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 343         netif_carrier_on(mac->dev);
 344
 345         mac->association_id = le16_to_cpup(&resp->aid);
 346 }
 347
 348 /* received frame handling functions */
 349 int
 350 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 351                                        struct ieee80211_assoc_response * resp,
 352                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 353 {
 354         /* NOTE: the network parameter has to be ignored by
 355          *       this code because it is the ieee80211's pointer
 356          *       to the struct, not ours (we made a copy)
 357          */
 358         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 359         u16 status = le16_to_cpup(&resp->status);
 360         struct ieee80211softmac_network *network = NULL;
 361         unsigned long flags;
 362
 363         if (unlikely(!mac->running))
 364                 return -ENODEV;
 365
 366         spin_lock_irqsave(&mac->lock, flags);
 367
 368         if (!mac->associnfo.associating) {
 369                 /* we race against the timeout function, so make sure
 370                  * only one of us can do work */
 371                 spin_unlock_irqrestore(&mac->lock, flags);
 372                 return 0;
 373         }
 374         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 375
 376         /* someone sending us things without us knowing him? Ignore. */
 377         if (!network) {
 378                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 379                 spin_unlock_irqrestore(&mac->lock, flags);
 380                 return 0;
 381         }
 382
 383         /* now that we know it was for us, we can cancel the timeout */
 384         cancel_delayed_work(&mac->associnfo.timeout);
 385
 386         switch (status) {
 387                 case 0:
 388                         dprintk(KERN_INFO PFX "associated!\n");
 389                         ieee80211softmac_associated(mac, resp, network);
 390                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 391                         break;
 392                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 393                         if (!network->auth_desynced_once) {
 394                                 /* there seem to be a few rare cases where our view of
 395                                  * the world is obscured, or buggy APs that don't DEAUTH
 396                                  * us properly. So we handle that, but allow it only once.
 397                                  */
 398                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 399                                 network->authenticated = 0;
 400                                 /* we don't want to do this more than once ... */
 401                                 network->auth_desynced_once = 1;
 402                                 schedule_work(&mac->associnfo.work);
 403                                 break;
 404                         }
 405                 default:
 406                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 407                         mac->associnfo.associating = 0;
 408                         mac->associnfo.bssvalid = 0;
 409                         mac->associated = 0;
 410                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 411         }
 412
 413         spin_unlock_irqrestore(&mac->lock, flags);
 414         return 0;
 415 }
 416
 417 int
 418 ieee80211softmac_handle_disassoc(struct net_device * dev,
 419                                  struct ieee80211_disassoc *disassoc)
 420 {
 421         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 422
 423         if (unlikely(!mac->running))
 424                 return -ENODEV;
 425
 426         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 427                 return 0;
 428
 429         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 430                 return 0;
 431
 432         dprintk(KERN_INFO PFX "got disassoc frame\n");
 433         ieee80211softmac_disassoc(mac);
 434
 435         /* try to reassociate */
 436         schedule_work(&mac->associnfo.work);
 437
 438         return 0;
 439 }
 440
 441 int
 442 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 443                                     struct ieee80211_reassoc_request * resp)
 444 {
 445         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 446         struct ieee80211softmac_network *network;
 447
 448         if (unlikely(!mac->running))
 449                 return -ENODEV;
 450
 451         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 452         if (!network) {
 453                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 454                 return 0;
 455         }
 456         schedule_work(&mac->associnfo.work);
 457
 458         return 0;
 459 }