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         /* Change the state to associating */
  51         spin_lock_irqsave(&mac->lock, flags);
  52         mac->associnfo.associating = 1;
  53         mac->associated = 0; /* just to make sure */
  54
  55         /* Set a timer for timeout */
  56         /* FIXME: make timeout configurable */
  57         if (likely(mac->running))
  58                 schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
  59         spin_unlock_irqrestore(&mac->lock, flags);
  60 }
  61
  62 void
  63 ieee80211softmac_assoc_timeout(void *d)
  64 {
  65         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
  66         unsigned long flags;
  67
  68         spin_lock_irqsave(&mac->lock, flags);
  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                 spin_unlock_irqrestore(&mac->lock, flags);
  73                 return;
  74         }
  75         mac->associnfo.associating = 0;
  76         mac->associnfo.bssvalid = 0;
  77         mac->associated = 0;
  78         spin_unlock_irqrestore(&mac->lock, flags);
  79
  80         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  81         /* FIXME: we need to know the network here. that requires a bit of restructuring */
  82         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
  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         /* try to find the requested network in our list, if we found one already */
 207         if (bssvalid || mac->associnfo.bssfixed)
 208                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 209
 210         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 211          * but only if we've scanned at least once (to get a better list of networks to
 212          * select from). If we have not scanned before, the !found logic below will be
 213          * invoked and will scan. */
 214         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 215         {
 216                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 217                                    because it cannot follow the best pointer logic. */
 218                 spin_lock_irqsave(&mac->ieee->lock, flags);
 219                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 220                         /* we're supposed to find the network with
 221                          * the best signal here, as we're asked to join
 222                          * any network with a specific ESSID, and many
 223                          * different ones could have that.
 224                          *
 225                          * I'll for now just go with the reported rssi.
 226                          *
 227                          * We also should take into account the rateset
 228                          * here to find the best BSSID to try.
 229                          */
 230                         if (network_matches_request(mac, net)) {
 231                                 if (!best) {
 232                                         best = net;
 233                                         rssi = best->stats.rssi;
 234                                         continue;
 235                                 }
 236                                 /* we already had a matching network, so
 237                                  * compare their properties to get the
 238                                  * better of the two ... (see above)
 239                                  */
 240                                 if (rssi < net->stats.rssi) {
 241                                         best = net;
 242                                         rssi = best->stats.rssi;
 243                                 }
 244                         }
 245                 }
 246                 /* if we unlock here, we might get interrupted and the `best'
 247                  * pointer could go stale */
 248                 if (best) {
 249                         found = ieee80211softmac_create_network(mac, best);
 250                         /* if found is still NULL, then we got -ENOMEM somewhere */
 251                         if (found)
 252                                 ieee80211softmac_add_network(mac, found);
 253                 }
 254                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 255         }
 256
 257         if (!found) {
 258                 if (mac->associnfo.scan_retry > 0) {
 259                         spin_lock_irqsave(&mac->lock, flags);
 260                         mac->associnfo.scan_retry--;
 261                         spin_unlock_irqrestore(&mac->lock, flags);
 262
 263                         /* We know of no such network. Let's scan.
 264                          * NB: this also happens if we had no memory to copy the network info...
 265                          * Maybe we can hope to have more memory after scanning finishes ;)
 266                          */
 267                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 268                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
 269                         if (ieee80211softmac_start_scan(mac))
 270                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 271                         return;
 272                 } else {
 273                         spin_lock_irqsave(&mac->lock, flags);
 274                         mac->associnfo.associating = 0;
 275                         mac->associated = 0;
 276                         spin_unlock_irqrestore(&mac->lock, flags);
 277
 278                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 279                         /* reset the retry counter for the next user request since we
 280                          * break out and don't reschedule ourselves after this point. */
 281                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 282                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 283                         return;
 284                 }
 285         }
 286
 287         /* reset the retry counter for the next user request since we
 288          * now found a net and will try to associate to it, but not
 289          * schedule this function again. */
 290         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 291         mac->associnfo.bssvalid = 1;
 292         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 293         /* copy the ESSID for displaying it */
 294         mac->associnfo.associate_essid.len = found->essid.len;
 295         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 296
 297         /* we found a network! authenticate (if necessary) and associate to it. */
 298         if (!found->authenticated) {
 299                 /* This relies on the fact that _auth_req only queues the work,
 300                  * otherwise adding the notification would be racy. */
 301                 if (!ieee80211softmac_auth_req(mac, found)) {
 302                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 303                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
 304                 } else {
 305                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 306                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 307                 }
 308                 return;
 309         }
 310         /* finally! now we can start associating */
 311         ieee80211softmac_assoc(mac, found);
 312 }
 313
 314 /* call this to do whatever is necessary when we're associated */
 315 static void
 316 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 317         struct ieee80211_assoc_response * resp,
 318         struct ieee80211softmac_network *net)
 319 {
 320         mac->associnfo.associating = 0;
 321         mac->associnfo.supported_rates = net->supported_rates;
 322         ieee80211softmac_recalc_txrates(mac);
 323
 324         mac->associated = 1;
 325         if (mac->set_bssid_filter)
 326                 mac->set_bssid_filter(mac->dev, net->bssid);
 327         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 328         netif_carrier_on(mac->dev);
 329
 330         mac->association_id = le16_to_cpup(&resp->aid);
 331 }
 332
 333 /* received frame handling functions */
 334 int
 335 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 336                                        struct ieee80211_assoc_response * resp,
 337                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 338 {
 339         /* NOTE: the network parameter has to be ignored by
 340          *       this code because it is the ieee80211's pointer
 341          *       to the struct, not ours (we made a copy)
 342          */
 343         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 344         u16 status = le16_to_cpup(&resp->status);
 345         struct ieee80211softmac_network *network = NULL;
 346         unsigned long flags;
 347
 348         if (unlikely(!mac->running))
 349                 return -ENODEV;
 350
 351         spin_lock_irqsave(&mac->lock, flags);
 352
 353         if (!mac->associnfo.associating) {
 354                 /* we race against the timeout function, so make sure
 355                  * only one of us can do work */
 356                 spin_unlock_irqrestore(&mac->lock, flags);
 357                 return 0;
 358         }
 359         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 360
 361         /* someone sending us things without us knowing him? Ignore. */
 362         if (!network) {
 363                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 364                 spin_unlock_irqrestore(&mac->lock, flags);
 365                 return 0;
 366         }
 367
 368         /* now that we know it was for us, we can cancel the timeout */
 369         cancel_delayed_work(&mac->associnfo.timeout);
 370
 371         switch (status) {
 372                 case 0:
 373                         dprintk(KERN_INFO PFX "associated!\n");
 374                         ieee80211softmac_associated(mac, resp, network);
 375                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 376                         break;
 377                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 378                         if (!network->auth_desynced_once) {
 379                                 /* there seem to be a few rare cases where our view of
 380                                  * the world is obscured, or buggy APs that don't DEAUTH
 381                                  * us properly. So we handle that, but allow it only once.
 382                                  */
 383                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 384                                 network->authenticated = 0;
 385                                 /* we don't want to do this more than once ... */
 386                                 network->auth_desynced_once = 1;
 387                                 schedule_work(&mac->associnfo.work);
 388                                 break;
 389                         }
 390                 default:
 391                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 392                         mac->associnfo.associating = 0;
 393                         mac->associnfo.bssvalid = 0;
 394                         mac->associated = 0;
 395                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 396         }
 397
 398         spin_unlock_irqrestore(&mac->lock, flags);
 399         return 0;
 400 }
 401
 402 int
 403 ieee80211softmac_handle_disassoc(struct net_device * dev,
 404                                  struct ieee80211_disassoc *disassoc)
 405 {
 406         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 407
 408         if (unlikely(!mac->running))
 409                 return -ENODEV;
 410
 411         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 412                 return 0;
 413
 414         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 415                 return 0;
 416
 417         dprintk(KERN_INFO PFX "got disassoc frame\n");
 418         ieee80211softmac_disassoc(mac);
 419
 420         /* try to reassociate */
 421         schedule_work(&mac->associnfo.work);
 422
 423         return 0;
 424 }
 425
 426 int
 427 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 428                                     struct ieee80211_reassoc_request * resp)
 429 {
 430         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 431         struct ieee80211softmac_network *network;
 432
 433         if (unlikely(!mac->running))
 434                 return -ENODEV;
 435
 436         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 437         if (!network) {
 438                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 439                 return 0;
 440         }
 441         schedule_work(&mac->associnfo.work);
 442
 443         return 0;
 444 }