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         function_enter();
  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         spin_unlock_irqrestore(&mac->lock, flags);
  55
  56         /* Set a timer for timeout */
  57         /* FIXME: make timeout configurable */
  58         schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
  59 }
  60
  61 void
  62 ieee80211softmac_assoc_timeout(void *d)
  63 {
  64         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
  65         unsigned long flags;
  66
  67         function_enter();
  68
  69         spin_lock_irqsave(&mac->lock, flags);
  70         /* we might race against ieee80211softmac_handle_assoc_response,
  71          * so make sure only one of us does something */
  72         if (!mac->associnfo.associating) {
  73                 spin_unlock_irqrestore(&mac->lock, flags);
  74                 return;
  75         }
  76         mac->associnfo.associating = 0;
  77         mac->associnfo.bssvalid = 0;
  78         mac->associated = 0;
  79         spin_unlock_irqrestore(&mac->lock, flags);
  80
  81         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  82         /* FIXME: we need to know the network here. that requires a bit of restructuring */
  83         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
  84 }
  85
  86 static void
  87 ieee80211softmac_reassoc(struct ieee80211softmac_device *mac)
  88 {
  89         function_enter();
  90 }
  91
  92
  93 /* Sends out a disassociation request to the desired AP */
  94 static void
  95 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
  96 {
  97         unsigned long flags;
  98         struct ieee80211softmac_network *found;
  99         function_enter();
 100
 101         if (mac->associnfo.bssvalid && mac->associated) {
 102                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 103                 if (found)
 104                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
 105         } else if (mac->associnfo.associating) {
 106                 cancel_delayed_work(&mac->associnfo.timeout);
 107         }
 108
 109         /* Change our state */
 110         spin_lock_irqsave(&mac->lock, flags);
 111         /* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
 112         mac->associated = 0;
 113         mac->associnfo.associating = 0;
 114         spin_unlock_irqrestore(&mac->lock, flags);
 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, search, found;
 121         u8 rate, search_rate;
 122
 123         for (idx = 0; idx < (from_len); idx++) {
 124                 rate = (from)[idx];
 125                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 126                         continue;
 127                 found = 0;
 128                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 129                 for (search = 0; search < mac->ratesinfo.count; search++) {
 130                         search_rate = mac->ratesinfo.rates[search];
 131                         search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 132                         if (rate == search_rate) {
 133                                 found = 1;
 134                                 break;
 135                         }
 136                 }
 137                 if (!found)
 138                         return 0;
 139         }
 140         return 1;
 141 }
 142
 143 static int
 144 network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
 145 {
 146         /* we cannot associate to networks whose name we don't know */
 147         if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
 148                 return 0;
 149         /* do not associate to a network whose BSSBasicRateSet we cannot support */
 150         if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
 151                 return 0;
 152         /* do we really need to check the ex rates? */
 153         if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
 154                 return 0;
 155
 156         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 157         if (mac->associnfo.req_essid.len == 0
 158             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 159                 return 1;
 160         if (net->ssid_len != mac->associnfo.req_essid.len)
 161                 return 0;
 162         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 163                 return 1;
 164         return 0;
 165 }
 166
 167 static void
 168 ieee80211softmac_assoc_notify(struct net_device *dev, void *context)
 169 {
 170         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 171         ieee80211softmac_assoc_work((void*)mac);
 172 }
 173
 174 /* This function is called to handle userspace requests (asynchronously) */
 175 void
 176 ieee80211softmac_assoc_work(void *d)
 177 {
 178         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 179         struct ieee80211softmac_network *found = NULL;
 180         struct ieee80211_network *net = NULL, *best = NULL;
 181         unsigned long flags;
 182
 183         function_enter();
 184
 185         /* meh */
 186         if (mac->associated)
 187                 ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 188
 189         /* try to find the requested network in our list, if we found one already */
 190         if (mac->associnfo.bssvalid)
 191                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 192
 193         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 194          * but only if we've scanned at least once (to get a better list of networks to
 195          * select from). If we have not scanned before, the !found logic below will be
 196          * invoked and will scan. */
 197         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 198         {
 199                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 200                                    because it cannot follow the best pointer logic. */
 201                 spin_lock_irqsave(&mac->ieee->lock, flags);
 202                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 203                         /* we're supposed to find the network with
 204                          * the best signal here, as we're asked to join
 205                          * any network with a specific ESSID, and many
 206                          * different ones could have that.
 207                          *
 208                          * I'll for now just go with the reported rssi.
 209                          *
 210                          * We also should take into account the rateset
 211                          * here to find the best BSSID to try.
 212                          */
 213                         if (network_matches_request(mac, net)) {
 214                                 if (!best) {
 215                                         best = net;
 216                                         rssi = best->stats.rssi;
 217                                         continue;
 218                                 }
 219                                 /* we already had a matching network, so
 220                                  * compare their properties to get the
 221                                  * better of the two ... (see above)
 222                                  */
 223                                 if (rssi < net->stats.rssi) {
 224                                         best = net;
 225                                         rssi = best->stats.rssi;
 226                                 }
 227                         }
 228                 }
 229                 /* if we unlock here, we might get interrupted and the `best'
 230                  * pointer could go stale */
 231                 if (best) {
 232                         found = ieee80211softmac_create_network(mac, best);
 233                         /* if found is still NULL, then we got -ENOMEM somewhere */
 234                         if (found)
 235                                 ieee80211softmac_add_network(mac, found);
 236                 }
 237                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 238         }
 239
 240         if (!found) {
 241                 if (mac->associnfo.scan_retry > 0) {
 242                         spin_lock_irqsave(&mac->lock, flags);
 243                         mac->associnfo.scan_retry--;
 244                         spin_unlock_irqrestore(&mac->lock, flags);
 245
 246                         /* We know of no such network. Let's scan.
 247                          * NB: this also happens if we had no memory to copy the network info...
 248                          * Maybe we can hope to have more memory after scanning finishes ;)
 249                          */
 250                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 251                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 252                         if (ieee80211softmac_start_scan(mac))
 253                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 254                         return;
 255                 }
 256                 else {
 257                         spin_lock_irqsave(&mac->lock, flags);
 258                         mac->associnfo.associating = 0;
 259                         mac->associated = 0;
 260                         spin_unlock_irqrestore(&mac->lock, flags);
 261
 262                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 263                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 264                         return;
 265                 }
 266         }
 267
 268         mac->associnfo.bssvalid = 1;
 269         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 270         /* copy the ESSID for displaying it */
 271         mac->associnfo.associate_essid.len = found->essid.len;
 272         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 273
 274         /* we found a network! authenticate (if necessary) and associate to it. */
 275         if (!found->authenticated) {
 276                 /* This relies on the fact that _auth_req only queues the work,
 277                  * otherwise adding the notification would be racy. */
 278                 if (!ieee80211softmac_auth_req(mac, found)) {
 279                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 280                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 281                 } else {
 282                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 283                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 284                 }
 285                 return;
 286         }
 287         /* finally! now we can start associating */
 288         ieee80211softmac_assoc(mac, found);
 289 }
 290
 291 /* call this to do whatever is necessary when we're associated */
 292 static void
 293 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 294         struct ieee80211_assoc_response * resp,
 295         struct ieee80211softmac_network *net)
 296 {
 297         mac->associnfo.associating = 0;
 298         mac->associated = 1;
 299         if (mac->set_bssid_filter)
 300                 mac->set_bssid_filter(mac->dev, net->bssid);
 301         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 302         netif_carrier_on(mac->dev);
 303
 304         mac->association_id = le16_to_cpup(&resp->aid);
 305 }
 306
 307 /* received frame handling functions */
 308 int
 309 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 310                                        struct ieee80211_assoc_response * resp,
 311                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 312 {
 313         /* NOTE: the network parameter has to be ignored by
 314          *       this code because it is the ieee80211's pointer
 315          *       to the struct, not ours (we made a copy)
 316          */
 317         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 318         u16 status = le16_to_cpup(&resp->status);
 319         struct ieee80211softmac_network *network = NULL;
 320         unsigned long flags;
 321
 322         spin_lock_irqsave(&mac->lock, flags);
 323
 324         if (!mac->associnfo.associating) {
 325                 /* we race against the timeout function, so make sure
 326                  * only one of us can do work */
 327                 spin_unlock_irqrestore(&mac->lock, flags);
 328                 return 0;
 329         }
 330         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 331
 332         /* someone sending us things without us knowing him? Ignore. */
 333         if (!network) {
 334                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 335                 spin_unlock_irqrestore(&mac->lock, flags);
 336                 return 0;
 337         }
 338
 339         /* now that we know it was for us, we can cancel the timeout */
 340         cancel_delayed_work(&mac->associnfo.timeout);
 341
 342         switch (status) {
 343                 case 0:
 344                         dprintk(KERN_INFO PFX "associated!\n");
 345                         ieee80211softmac_associated(mac, resp, network);
 346                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 347                         break;
 348                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 349                         if (!network->auth_desynced_once) {
 350                                 /* there seem to be a few rare cases where our view of
 351                                  * the world is obscured, or buggy APs that don't DEAUTH
 352                                  * us properly. So we handle that, but allow it only once.
 353                                  */
 354                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 355                                 network->authenticated = 0;
 356                                 /* we don't want to do this more than once ... */
 357                                 network->auth_desynced_once = 1;
 358                                 schedule_work(&mac->associnfo.work);
 359                                 break;
 360                         }
 361                 default:
 362                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 363                         mac->associnfo.associating = 0;
 364                         mac->associnfo.bssvalid = 0;
 365                         mac->associated = 0;
 366                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 367         }
 368
 369         spin_unlock_irqrestore(&mac->lock, flags);
 370         return 0;
 371 }
 372
 373 int
 374 ieee80211softmac_handle_disassoc(struct net_device * dev,
 375                                  struct ieee80211_disassoc *disassoc)
 376 {
 377         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 378         unsigned long flags;
 379         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 380                 return 0;
 381         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 382                 return 0;
 383         dprintk(KERN_INFO PFX "got disassoc frame\n");
 384         netif_carrier_off(dev);
 385         spin_lock_irqsave(&mac->lock, flags);
 386         mac->associnfo.bssvalid = 0;
 387         mac->associated = 0;
 388         schedule_work(&mac->associnfo.work);
 389         spin_unlock_irqrestore(&mac->lock, flags);
 390
 391         return 0;
 392 }
 393
 394 int
 395 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 396                                     struct ieee80211_reassoc_request * resp)
 397 {
 398         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 399         struct ieee80211softmac_network *network;
 400
 401         function_enter();
 402
 403         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 404         if (!network) {
 405                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 406                 return 0;
 407         }
 408         ieee80211softmac_assoc(mac, network);
 409         return 0;
 410 }