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