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         struct ieee80211softmac_network *n;
  65         unsigned long flags;
  66
  67         spin_lock_irqsave(&mac->lock, flags);
  68         /* we might race against ieee80211softmac_handle_assoc_response,
  69          * so make sure only one of us does something */
  70         if (!mac->associnfo.associating) {
  71                 spin_unlock_irqrestore(&mac->lock, flags);
  72                 return;
  73         }
  74         mac->associnfo.associating = 0;
  75         mac->associnfo.bssvalid = 0;
  76         mac->associated = 0;
  77
  78         n = ieee80211softmac_get_network_by_bssid_locked(mac, mac->associnfo.bssid);
  79         spin_unlock_irqrestore(&mac->lock, flags);
  80
  81         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  82         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, n);
  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->associated = 0;
  97         mac->associnfo.bssvalid = 0;
  98         mac->associnfo.associating = 0;
  99         ieee80211softmac_init_txrates(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->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((void*)mac);
 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((void*)mac);
 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(void *d)
 192 {
 193         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 194         struct ieee80211softmac_network *found = NULL;
 195         struct ieee80211_network *net = NULL, *best = NULL;
 196         int bssvalid;
 197         unsigned long flags;
 198
 199         /* ieee80211_disassoc might clear this */
 200         bssvalid = mac->associnfo.bssvalid;
 201
 202         /* meh */
 203         if (mac->associated)
 204                 ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 205
 206         spin_lock_irqsave(&mac->lock, flags);
 207         mac->associnfo.associating = 1;
 208         spin_unlock_irqrestore(&mac->lock, flags);
 209
 210         /* try to find the requested network in our list, if we found one already */
 211         if (bssvalid || mac->associnfo.bssfixed)
 212                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 213
 214         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 215          * but only if we've scanned at least once (to get a better list of networks to
 216          * select from). If we have not scanned before, the !found logic below will be
 217          * invoked and will scan. */
 218         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 219         {
 220                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 221                                    because it cannot follow the best pointer logic. */
 222                 spin_lock_irqsave(&mac->ieee->lock, flags);
 223                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 224                         /* we're supposed to find the network with
 225                          * the best signal here, as we're asked to join
 226                          * any network with a specific ESSID, and many
 227                          * different ones could have that.
 228                          *
 229                          * I'll for now just go with the reported rssi.
 230                          *
 231                          * We also should take into account the rateset
 232                          * here to find the best BSSID to try.
 233                          */
 234                         if (network_matches_request(mac, net)) {
 235                                 if (!best) {
 236                                         best = net;
 237                                         rssi = best->stats.rssi;
 238                                         continue;
 239                                 }
 240                                 /* we already had a matching network, so
 241                                  * compare their properties to get the
 242                                  * better of the two ... (see above)
 243                                  */
 244                                 if (rssi < net->stats.rssi) {
 245                                         best = net;
 246                                         rssi = best->stats.rssi;
 247                                 }
 248                         }
 249                 }
 250                 /* if we unlock here, we might get interrupted and the `best'
 251                  * pointer could go stale */
 252                 if (best) {
 253                         found = ieee80211softmac_create_network(mac, best);
 254                         /* if found is still NULL, then we got -ENOMEM somewhere */
 255                         if (found)
 256                                 ieee80211softmac_add_network(mac, found);
 257                 }
 258                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 259         }
 260
 261         if (!found) {
 262                 if (mac->associnfo.scan_retry > 0) {
 263                         spin_lock_irqsave(&mac->lock, flags);
 264                         mac->associnfo.scan_retry--;
 265                         spin_unlock_irqrestore(&mac->lock, flags);
 266
 267                         /* We know of no such network. Let's scan.
 268                          * NB: this also happens if we had no memory to copy the network info...
 269                          * Maybe we can hope to have more memory after scanning finishes ;)
 270                          */
 271                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 272                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
 273                         if (ieee80211softmac_start_scan(mac))
 274                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 275                         return;
 276                 } else {
 277                         spin_lock_irqsave(&mac->lock, flags);
 278                         mac->associnfo.associating = 0;
 279                         mac->associated = 0;
 280                         spin_unlock_irqrestore(&mac->lock, flags);
 281
 282                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 283                         /* reset the retry counter for the next user request since we
 284                          * break out and don't reschedule ourselves after this point. */
 285                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 286                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 287                         return;
 288                 }
 289         }
 290
 291         /* reset the retry counter for the next user request since we
 292          * now found a net and will try to associate to it, but not
 293          * schedule this function again. */
 294         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 295         mac->associnfo.bssvalid = 1;
 296         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 297         /* copy the ESSID for displaying it */
 298         mac->associnfo.associate_essid.len = found->essid.len;
 299         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 300
 301         /* we found a network! authenticate (if necessary) and associate to it. */
 302         if (found->authenticating) {
 303                 dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
 304                 if(!mac->associnfo.assoc_wait) {
 305                         mac->associnfo.assoc_wait = 1;
 306                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 307                 }
 308                 return;
 309         }
 310         if (!found->authenticated && !found->authenticating) {
 311                 /* This relies on the fact that _auth_req only queues the work,
 312                  * otherwise adding the notification would be racy. */
 313                 if (!ieee80211softmac_auth_req(mac, found)) {
 314                         if(!mac->associnfo.assoc_wait) {
 315                                 dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
 316                                 mac->associnfo.assoc_wait = 1;
 317                                 ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 318                         }
 319                 } else {
 320                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 321                         mac->associnfo.assoc_wait = 0;
 322                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 323                 }
 324                 return;
 325         }
 326         /* finally! now we can start associating */
 327         mac->associnfo.assoc_wait = 0;
 328         ieee80211softmac_assoc(mac, found);
 329 }
 330
 331 /* call this to do whatever is necessary when we're associated */
 332 static void
 333 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 334         struct ieee80211_assoc_response * resp,
 335         struct ieee80211softmac_network *net)
 336 {
 337         mac->associnfo.associating = 0;
 338         mac->associnfo.supported_rates = net->supported_rates;
 339         ieee80211softmac_recalc_txrates(mac);
 340
 341         mac->associated = 1;
 342         if (mac->set_bssid_filter)
 343                 mac->set_bssid_filter(mac->dev, net->bssid);
 344         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 345         netif_carrier_on(mac->dev);
 346
 347         mac->association_id = le16_to_cpup(&resp->aid);
 348 }
 349
 350 /* received frame handling functions */
 351 int
 352 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 353                                        struct ieee80211_assoc_response * resp,
 354                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 355 {
 356         /* NOTE: the network parameter has to be ignored by
 357          *       this code because it is the ieee80211's pointer
 358          *       to the struct, not ours (we made a copy)
 359          */
 360         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 361         u16 status = le16_to_cpup(&resp->status);
 362         struct ieee80211softmac_network *network = NULL;
 363         unsigned long flags;
 364
 365         if (unlikely(!mac->running))
 366                 return -ENODEV;
 367
 368         spin_lock_irqsave(&mac->lock, flags);
 369
 370         if (!mac->associnfo.associating) {
 371                 /* we race against the timeout function, so make sure
 372                  * only one of us can do work */
 373                 spin_unlock_irqrestore(&mac->lock, flags);
 374                 return 0;
 375         }
 376         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 377
 378         /* someone sending us things without us knowing him? Ignore. */
 379         if (!network) {
 380                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 381                 spin_unlock_irqrestore(&mac->lock, flags);
 382                 return 0;
 383         }
 384
 385         /* now that we know it was for us, we can cancel the timeout */
 386         cancel_delayed_work(&mac->associnfo.timeout);
 387
 388         switch (status) {
 389                 case 0:
 390                         dprintk(KERN_INFO PFX "associated!\n");
 391                         ieee80211softmac_associated(mac, resp, network);
 392                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 393                         break;
 394                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 395                         if (!network->auth_desynced_once) {
 396                                 /* there seem to be a few rare cases where our view of
 397                                  * the world is obscured, or buggy APs that don't DEAUTH
 398                                  * us properly. So we handle that, but allow it only once.
 399                                  */
 400                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 401                                 network->authenticated = 0;
 402                                 /* we don't want to do this more than once ... */
 403                                 network->auth_desynced_once = 1;
 404                                 schedule_work(&mac->associnfo.work);
 405                                 break;
 406                         }
 407                 default:
 408                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 409                         mac->associnfo.associating = 0;
 410                         mac->associnfo.bssvalid = 0;
 411                         mac->associated = 0;
 412                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 413         }
 414
 415         spin_unlock_irqrestore(&mac->lock, flags);
 416         return 0;
 417 }
 418
 419 int
 420 ieee80211softmac_handle_disassoc(struct net_device * dev,
 421                                  struct ieee80211_disassoc *disassoc)
 422 {
 423         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 424
 425         if (unlikely(!mac->running))
 426                 return -ENODEV;
 427
 428         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 429                 return 0;
 430
 431         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 432                 return 0;
 433
 434         dprintk(KERN_INFO PFX "got disassoc frame\n");
 435         ieee80211softmac_disassoc(mac);
 436
 437         /* try to reassociate */
 438         schedule_work(&mac->associnfo.work);
 439
 440         return 0;
 441 }
 442
 443 int
 444 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 445                                     struct ieee80211_reassoc_request * resp)
 446 {
 447         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 448         struct ieee80211softmac_network *network;
 449
 450         if (unlikely(!mac->running))
 451                 return -ENODEV;
 452
 453         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 454         if (!network) {
 455                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 456                 return 0;
 457         }
 458         schedule_work(&mac->associnfo.work);
 459
 460         return 0;
 461 }