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         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         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         spin_unlock_irqrestore(&mac->lock, flags);
  78
  79         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  80         /* FIXME: we need to know the network here. that requires a bit of restructuring */
  81         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
  82 }
  83
  84 /* Sends out a disassociation request to the desired AP */
  85 static void
  86 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
  87 {
  88         unsigned long flags;
  89         struct ieee80211softmac_network *found;
  90
  91         if (mac->associnfo.bssvalid && mac->associated) {
  92                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
  93                 if (found)
  94                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
  95         } else if (mac->associnfo.associating) {
  96                 cancel_delayed_work(&mac->associnfo.timeout);
  97         }
  98
  99         /* Change our state */
 100         spin_lock_irqsave(&mac->lock, flags);
 101         /* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
 102         mac->associated = 0;
 103         mac->associnfo.associating = 0;
 104         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
 105         spin_unlock_irqrestore(&mac->lock, flags);
 106 }
 107
 108 static inline int
 109 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
 110 {
 111         int idx, search, found;
 112         u8 rate, search_rate;
 113
 114         for (idx = 0; idx < (from_len); idx++) {
 115                 rate = (from)[idx];
 116                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 117                         continue;
 118                 found = 0;
 119                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 120                 for (search = 0; search < mac->ratesinfo.count; search++) {
 121                         search_rate = mac->ratesinfo.rates[search];
 122                         search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 123                         if (rate == search_rate) {
 124                                 found = 1;
 125                                 break;
 126                         }
 127                 }
 128                 if (!found)
 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(struct net_device *dev, void *context)
 166 {
 167         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 168         ieee80211softmac_assoc_work((void*)mac);
 169 }
 170
 171 /* This function is called to handle userspace requests (asynchronously) */
 172 void
 173 ieee80211softmac_assoc_work(void *d)
 174 {
 175         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 176         struct ieee80211softmac_network *found = NULL;
 177         struct ieee80211_network *net = NULL, *best = NULL;
 178         unsigned long flags;
 179
 180         /* meh */
 181         if (mac->associated)
 182                 ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 183
 184         /* try to find the requested network in our list, if we found one already */
 185         if (mac->associnfo.bssvalid || mac->associnfo.bssfixed)
 186                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 187
 188         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 189          * but only if we've scanned at least once (to get a better list of networks to
 190          * select from). If we have not scanned before, the !found logic below will be
 191          * invoked and will scan. */
 192         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 193         {
 194                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 195                                    because it cannot follow the best pointer logic. */
 196                 spin_lock_irqsave(&mac->ieee->lock, flags);
 197                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 198                         /* we're supposed to find the network with
 199                          * the best signal here, as we're asked to join
 200                          * any network with a specific ESSID, and many
 201                          * different ones could have that.
 202                          *
 203                          * I'll for now just go with the reported rssi.
 204                          *
 205                          * We also should take into account the rateset
 206                          * here to find the best BSSID to try.
 207                          */
 208                         if (network_matches_request(mac, net)) {
 209                                 if (!best) {
 210                                         best = net;
 211                                         rssi = best->stats.rssi;
 212                                         continue;
 213                                 }
 214                                 /* we already had a matching network, so
 215                                  * compare their properties to get the
 216                                  * better of the two ... (see above)
 217                                  */
 218                                 if (rssi < net->stats.rssi) {
 219                                         best = net;
 220                                         rssi = best->stats.rssi;
 221                                 }
 222                         }
 223                 }
 224                 /* if we unlock here, we might get interrupted and the `best'
 225                  * pointer could go stale */
 226                 if (best) {
 227                         found = ieee80211softmac_create_network(mac, best);
 228                         /* if found is still NULL, then we got -ENOMEM somewhere */
 229                         if (found)
 230                                 ieee80211softmac_add_network(mac, found);
 231                 }
 232                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 233         }
 234
 235         if (!found) {
 236                 if (mac->associnfo.scan_retry > 0) {
 237                         spin_lock_irqsave(&mac->lock, flags);
 238                         mac->associnfo.scan_retry--;
 239                         spin_unlock_irqrestore(&mac->lock, flags);
 240
 241                         /* We know of no such network. Let's scan.
 242                          * NB: this also happens if we had no memory to copy the network info...
 243                          * Maybe we can hope to have more memory after scanning finishes ;)
 244                          */
 245                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 246                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 247                         if (ieee80211softmac_start_scan(mac))
 248                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 249                         return;
 250                 } else {
 251                         spin_lock_irqsave(&mac->lock, flags);
 252                         mac->associnfo.associating = 0;
 253                         mac->associated = 0;
 254                         spin_unlock_irqrestore(&mac->lock, flags);
 255
 256                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 257                         /* reset the retry counter for the next user request since we
 258                          * break out and don't reschedule ourselves after this point. */
 259                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 260                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 261                         return;
 262                 }
 263         }
 264
 265         /* reset the retry counter for the next user request since we
 266          * now found a net and will try to associate to it, but not
 267          * schedule this function again. */
 268         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 269         mac->associnfo.bssvalid = 1;
 270         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 271         /* copy the ESSID for displaying it */
 272         mac->associnfo.associate_essid.len = found->essid.len;
 273         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 274
 275         /* we found a network! authenticate (if necessary) and associate to it. */
 276         if (!found->authenticated) {
 277                 /* This relies on the fact that _auth_req only queues the work,
 278                  * otherwise adding the notification would be racy. */
 279                 if (!ieee80211softmac_auth_req(mac, found)) {
 280                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 281                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 282                 } else {
 283                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 284                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 285                 }
 286                 return;
 287         }
 288         /* finally! now we can start associating */
 289         ieee80211softmac_assoc(mac, found);
 290 }
 291
 292 /* call this to do whatever is necessary when we're associated */
 293 static void
 294 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 295         struct ieee80211_assoc_response * resp,
 296         struct ieee80211softmac_network *net)
 297 {
 298         mac->associnfo.associating = 0;
 299         mac->associated = 1;
 300         if (mac->set_bssid_filter)
 301                 mac->set_bssid_filter(mac->dev, net->bssid);
 302         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 303         netif_carrier_on(mac->dev);
 304
 305         mac->association_id = le16_to_cpup(&resp->aid);
 306 }
 307
 308 /* received frame handling functions */
 309 int
 310 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 311                                        struct ieee80211_assoc_response * resp,
 312                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 313 {
 314         /* NOTE: the network parameter has to be ignored by
 315          *       this code because it is the ieee80211's pointer
 316          *       to the struct, not ours (we made a copy)
 317          */
 318         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 319         u16 status = le16_to_cpup(&resp->status);
 320         struct ieee80211softmac_network *network = NULL;
 321         unsigned long flags;
 322
 323         spin_lock_irqsave(&mac->lock, flags);
 324
 325         if (!mac->associnfo.associating) {
 326                 /* we race against the timeout function, so make sure
 327                  * only one of us can do work */
 328                 spin_unlock_irqrestore(&mac->lock, flags);
 329                 return 0;
 330         }
 331         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 332
 333         /* someone sending us things without us knowing him? Ignore. */
 334         if (!network) {
 335                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 336                 spin_unlock_irqrestore(&mac->lock, flags);
 337                 return 0;
 338         }
 339
 340         /* now that we know it was for us, we can cancel the timeout */
 341         cancel_delayed_work(&mac->associnfo.timeout);
 342
 343         switch (status) {
 344                 case 0:
 345                         dprintk(KERN_INFO PFX "associated!\n");
 346                         ieee80211softmac_associated(mac, resp, network);
 347                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 348                         break;
 349                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 350                         if (!network->auth_desynced_once) {
 351                                 /* there seem to be a few rare cases where our view of
 352                                  * the world is obscured, or buggy APs that don't DEAUTH
 353                                  * us properly. So we handle that, but allow it only once.
 354                                  */
 355                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 356                                 network->authenticated = 0;
 357                                 /* we don't want to do this more than once ... */
 358                                 network->auth_desynced_once = 1;
 359                                 schedule_work(&mac->associnfo.work);
 360                                 break;
 361                         }
 362                 default:
 363                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 364                         mac->associnfo.associating = 0;
 365                         mac->associnfo.bssvalid = 0;
 366                         mac->associated = 0;
 367                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 368         }
 369
 370         spin_unlock_irqrestore(&mac->lock, flags);
 371         return 0;
 372 }
 373
 374 int
 375 ieee80211softmac_handle_disassoc(struct net_device * dev,
 376                                  struct ieee80211_disassoc *disassoc)
 377 {
 378         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 379         unsigned long flags;
 380         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 381                 return 0;
 382         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 383                 return 0;
 384         dprintk(KERN_INFO PFX "got disassoc frame\n");
 385         netif_carrier_off(dev);
 386         spin_lock_irqsave(&mac->lock, flags);
 387         mac->associnfo.bssvalid = 0;
 388         mac->associated = 0;
 389         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
 390         schedule_work(&mac->associnfo.work);
 391         spin_unlock_irqrestore(&mac->lock, flags);
 392
 393         return 0;
 394 }
 395
 396 int
 397 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 398                                     struct ieee80211_reassoc_request * resp)
 399 {
 400         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 401         struct ieee80211softmac_network *network;
 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         schedule_work(&mac->associnfo.work);
 409
 410         return 0;
 411 }