err.no Git - linux-2.6/blob - 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 /* Sends out a disassociation request to the desired AP */
  87 static void
  88 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
  89 {
  90         unsigned long flags;
  91         struct ieee80211softmac_network *found;
  92         function_enter();
  93
  94         if (mac->associnfo.bssvalid && mac->associated) {
  95                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
  96                 if (found)
  97                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
  98         } else if (mac->associnfo.associating) {
  99                 cancel_delayed_work(&mac->associnfo.timeout);
 100         }
 101
 102         /* Change our state */
 103         spin_lock_irqsave(&mac->lock, flags);
 104         /* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
 105         mac->associated = 0;
 106         mac->associnfo.associating = 0;
 107         spin_unlock_irqrestore(&mac->lock, flags);
 108 }
 109
 110 static inline int
 111 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
 112 {
 113         int idx, search, found;
 114         u8 rate, search_rate;
 115
 116         for (idx = 0; idx < (from_len); idx++) {
 117                 rate = (from)[idx];
 118                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 119                         continue;
 120                 found = 0;
 121                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 122                 for (search = 0; search < mac->ratesinfo.count; search++) {
 123                         search_rate = mac->ratesinfo.rates[search];
 124                         search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 125                         if (rate == search_rate) {
 126                                 found = 1;
 127                                 break;
 128                         }
 129                 }
 130                 if (!found)
 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         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 150         if (mac->associnfo.req_essid.len == 0
 151             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 152                 return 1;
 153         if (net->ssid_len != mac->associnfo.req_essid.len)
 154                 return 0;
 155         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 156                 return 1;
 157         return 0;
 158 }
 159
 160 static void
 161 ieee80211softmac_assoc_notify(struct net_device *dev, void *context)
 162 {
 163         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 164         ieee80211softmac_assoc_work((void*)mac);
 165 }
 166
 167 /* This function is called to handle userspace requests (asynchronously) */
 168 void
 169 ieee80211softmac_assoc_work(void *d)
 170 {
 171         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 172         struct ieee80211softmac_network *found = NULL;
 173         struct ieee80211_network *net = NULL, *best = NULL;
 174         unsigned long flags;
 175
 176         function_enter();
 177
 178         /* meh */
 179         if (mac->associated)
 180                 ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 181
 182         /* try to find the requested network in our list, if we found one already */
 183         if (mac->associnfo.bssvalid)
 184                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 185
 186         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 187          * but only if we've scanned at least once (to get a better list of networks to
 188          * select from). If we have not scanned before, the !found logic below will be
 189          * invoked and will scan. */
 190         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 191         {
 192                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 193                                    because it cannot follow the best pointer logic. */
 194                 spin_lock_irqsave(&mac->ieee->lock, flags);
 195                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 196                         /* we're supposed to find the network with
 197                          * the best signal here, as we're asked to join
 198                          * any network with a specific ESSID, and many
 199                          * different ones could have that.
 200                          *
 201                          * I'll for now just go with the reported rssi.
 202                          *
 203                          * We also should take into account the rateset
 204                          * here to find the best BSSID to try.
 205                          */
 206                         if (network_matches_request(mac, net)) {
 207                                 if (!best) {
 208                                         best = net;
 209                                         rssi = best->stats.rssi;
 210                                         continue;
 211                                 }
 212                                 /* we already had a matching network, so
 213                                  * compare their properties to get the
 214                                  * better of the two ... (see above)
 215                                  */
 216                                 if (rssi < net->stats.rssi) {
 217                                         best = net;
 218                                         rssi = best->stats.rssi;
 219                                 }
 220                         }
 221                 }
 222                 /* if we unlock here, we might get interrupted and the `best'
 223                  * pointer could go stale */
 224                 if (best) {
 225                         found = ieee80211softmac_create_network(mac, best);
 226                         /* if found is still NULL, then we got -ENOMEM somewhere */
 227                         if (found)
 228                                 ieee80211softmac_add_network(mac, found);
 229                 }
 230                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 231         }
 232
 233         if (!found) {
 234                 if (mac->associnfo.scan_retry > 0) {
 235                         spin_lock_irqsave(&mac->lock, flags);
 236                         mac->associnfo.scan_retry--;
 237                         spin_unlock_irqrestore(&mac->lock, flags);
 238
 239                         /* We know of no such network. Let's scan.
 240                          * NB: this also happens if we had no memory to copy the network info...
 241                          * Maybe we can hope to have more memory after scanning finishes ;)
 242                          */
 243                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 244                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 245                         if (ieee80211softmac_start_scan(mac))
 246                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 247                         return;
 248                 }
 249                 else {
 250                         spin_lock_irqsave(&mac->lock, flags);
 251                         mac->associnfo.associating = 0;
 252                         mac->associated = 0;
 253                         spin_unlock_irqrestore(&mac->lock, flags);
 254
 255                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 256                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 257                         return;
 258                 }
 259         }
 260
 261         mac->associnfo.bssvalid = 1;
 262         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 263         /* copy the ESSID for displaying it */
 264         mac->associnfo.associate_essid.len = found->essid.len;
 265         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 266
 267         /* we found a network! authenticate (if necessary) and associate to it. */
 268         if (!found->authenticated) {
 269                 /* This relies on the fact that _auth_req only queues the work,
 270                  * otherwise adding the notification would be racy. */
 271                 if (!ieee80211softmac_auth_req(mac, found)) {
 272                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 273                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 274                 } else {
 275                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 276                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 277                 }
 278                 return;
 279         }
 280         /* finally! now we can start associating */
 281         ieee80211softmac_assoc(mac, found);
 282 }
 283
 284 /* call this to do whatever is necessary when we're associated */
 285 static void
 286 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 287         struct ieee80211_assoc_response * resp,
 288         struct ieee80211softmac_network *net)
 289 {
 290         mac->associnfo.associating = 0;
 291         mac->associated = 1;
 292         if (mac->set_bssid_filter)
 293                 mac->set_bssid_filter(mac->dev, net->bssid);
 294         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 295         netif_carrier_on(mac->dev);
 296
 297         mac->association_id = le16_to_cpup(&resp->aid);
 298 }
 299
 300 /* received frame handling functions */
 301 int
 302 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 303                                        struct ieee80211_assoc_response * resp,
 304                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 305 {
 306         /* NOTE: the network parameter has to be ignored by
 307          *       this code because it is the ieee80211's pointer
 308          *       to the struct, not ours (we made a copy)
 309          */
 310         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 311         u16 status = le16_to_cpup(&resp->status);
 312         struct ieee80211softmac_network *network = NULL;
 313         unsigned long flags;
 314
 315         spin_lock_irqsave(&mac->lock, flags);
 316
 317         if (!mac->associnfo.associating) {
 318                 /* we race against the timeout function, so make sure
 319                  * only one of us can do work */
 320                 spin_unlock_irqrestore(&mac->lock, flags);
 321                 return 0;
 322         }
 323         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 324
 325         /* someone sending us things without us knowing him? Ignore. */
 326         if (!network) {
 327                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 328                 spin_unlock_irqrestore(&mac->lock, flags);
 329                 return 0;
 330         }
 331
 332         /* now that we know it was for us, we can cancel the timeout */
 333         cancel_delayed_work(&mac->associnfo.timeout);
 334
 335         switch (status) {
 336                 case 0:
 337                         dprintk(KERN_INFO PFX "associated!\n");
 338                         ieee80211softmac_associated(mac, resp, network);
 339                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 340                         break;
 341                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 342                         if (!network->auth_desynced_once) {
 343                                 /* there seem to be a few rare cases where our view of
 344                                  * the world is obscured, or buggy APs that don't DEAUTH
 345                                  * us properly. So we handle that, but allow it only once.
 346                                  */
 347                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 348                                 network->authenticated = 0;
 349                                 /* we don't want to do this more than once ... */
 350                                 network->auth_desynced_once = 1;
 351                                 schedule_work(&mac->associnfo.work);
 352                                 break;
 353                         }
 354                 default:
 355                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 356                         mac->associnfo.associating = 0;
 357                         mac->associnfo.bssvalid = 0;
 358                         mac->associated = 0;
 359                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 360         }
 361
 362         spin_unlock_irqrestore(&mac->lock, flags);
 363         return 0;
 364 }
 365
 366 int
 367 ieee80211softmac_handle_disassoc(struct net_device * dev,
 368                                  struct ieee80211_disassoc *disassoc)
 369 {
 370         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 371         unsigned long flags;
 372         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 373                 return 0;
 374         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 375                 return 0;
 376         dprintk(KERN_INFO PFX "got disassoc frame\n");
 377         netif_carrier_off(dev);
 378         spin_lock_irqsave(&mac->lock, flags);
 379         mac->associnfo.bssvalid = 0;
 380         mac->associated = 0;
 381         schedule_work(&mac->associnfo.work);
 382         spin_unlock_irqrestore(&mac->lock, flags);
 383
 384         return 0;
 385 }
 386
 387 int
 388 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 389                                     struct ieee80211_reassoc_request * resp)
 390 {
 391         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 392         struct ieee80211softmac_network *network;
 393
 394         function_enter();
 395
 396         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 397         if (!network) {
 398                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 399                 return 0;
 400         }
 401         ieee80211softmac_assoc(mac, network);
 402         return 0;
 403 }