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 /* Sends out a disassociation request to the desired AP */
  86 static void
  87 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
  88 {
  89         unsigned long flags;
  90         struct ieee80211softmac_network *found;
  91
  92         if (mac->associnfo.bssvalid && mac->associated) {
  93                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
  94                 if (found)
  95                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
  96         } else if (mac->associnfo.associating) {
  97                 cancel_delayed_work(&mac->associnfo.timeout);
  98         }
  99
 100         /* Change our state */
 101         spin_lock_irqsave(&mac->lock, flags);
 102         /* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
 103         mac->associated = 0;
 104         mac->associnfo.associating = 0;
 105         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
 106         spin_unlock_irqrestore(&mac->lock, flags);
 107 }
 108
 109 static inline int
 110 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
 111 {
 112         int idx, search, found;
 113         u8 rate, search_rate;
 114
 115         for (idx = 0; idx < (from_len); idx++) {
 116                 rate = (from)[idx];
 117                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 118                         continue;
 119                 found = 0;
 120                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 121                 for (search = 0; search < mac->ratesinfo.count; search++) {
 122                         search_rate = mac->ratesinfo.rates[search];
 123                         search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 124                         if (rate == search_rate) {
 125                                 found = 1;
 126                                 break;
 127                         }
 128                 }
 129                 if (!found)
 130                         return 0;
 131         }
 132         return 1;
 133 }
 134
 135 static int
 136 network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
 137 {
 138         /* we cannot associate to networks whose name we don't know */
 139         if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
 140                 return 0;
 141         /* do not associate to a network whose BSSBasicRateSet we cannot support */
 142         if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
 143                 return 0;
 144         /* do we really need to check the ex rates? */
 145         if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
 146                 return 0;
 147
 148         /* assume that users know what they're doing ...
 149          * (note we don't let them select a net we're incompatible with) */
 150         if (mac->associnfo.bssfixed) {
 151                 return !memcmp(mac->associnfo.bssid, net->bssid, ETH_ALEN);
 152         }
 153
 154         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 155         if (mac->associnfo.req_essid.len == 0
 156             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 157                 return 1;
 158         if (net->ssid_len != mac->associnfo.req_essid.len)
 159                 return 0;
 160         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 161                 return 1;
 162         return 0;
 163 }
 164
 165 static void
 166 ieee80211softmac_assoc_notify(struct net_device *dev, void *context)
 167 {
 168         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 169         ieee80211softmac_assoc_work((void*)mac);
 170 }
 171
 172 /* This function is called to handle userspace requests (asynchronously) */
 173 void
 174 ieee80211softmac_assoc_work(void *d)
 175 {
 176         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 177         struct ieee80211softmac_network *found = NULL;
 178         struct ieee80211_network *net = NULL, *best = NULL;
 179         unsigned long flags;
 180
 181         /* meh */
 182         if (mac->associated)
 183                 ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 184
 185         /* try to find the requested network in our list, if we found one already */
 186         if (mac->associnfo.bssvalid || mac->associnfo.bssfixed)
 187                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 188
 189         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 190          * but only if we've scanned at least once (to get a better list of networks to
 191          * select from). If we have not scanned before, the !found logic below will be
 192          * invoked and will scan. */
 193         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 194         {
 195                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 196                                    because it cannot follow the best pointer logic. */
 197                 spin_lock_irqsave(&mac->ieee->lock, flags);
 198                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 199                         /* we're supposed to find the network with
 200                          * the best signal here, as we're asked to join
 201                          * any network with a specific ESSID, and many
 202                          * different ones could have that.
 203                          *
 204                          * I'll for now just go with the reported rssi.
 205                          *
 206                          * We also should take into account the rateset
 207                          * here to find the best BSSID to try.
 208                          */
 209                         if (network_matches_request(mac, net)) {
 210                                 if (!best) {
 211                                         best = net;
 212                                         rssi = best->stats.rssi;
 213                                         continue;
 214                                 }
 215                                 /* we already had a matching network, so
 216                                  * compare their properties to get the
 217                                  * better of the two ... (see above)
 218                                  */
 219                                 if (rssi < net->stats.rssi) {
 220                                         best = net;
 221                                         rssi = best->stats.rssi;
 222                                 }
 223                         }
 224                 }
 225                 /* if we unlock here, we might get interrupted and the `best'
 226                  * pointer could go stale */
 227                 if (best) {
 228                         found = ieee80211softmac_create_network(mac, best);
 229                         /* if found is still NULL, then we got -ENOMEM somewhere */
 230                         if (found)
 231                                 ieee80211softmac_add_network(mac, found);
 232                 }
 233                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 234         }
 235
 236         if (!found) {
 237                 if (mac->associnfo.scan_retry > 0) {
 238                         spin_lock_irqsave(&mac->lock, flags);
 239                         mac->associnfo.scan_retry--;
 240                         spin_unlock_irqrestore(&mac->lock, flags);
 241
 242                         /* We know of no such network. Let's scan.
 243                          * NB: this also happens if we had no memory to copy the network info...
 244                          * Maybe we can hope to have more memory after scanning finishes ;)
 245                          */
 246                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 247                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 248                         if (ieee80211softmac_start_scan(mac))
 249                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 250                         return;
 251                 } else {
 252                         spin_lock_irqsave(&mac->lock, flags);
 253                         mac->associnfo.associating = 0;
 254                         mac->associated = 0;
 255                         spin_unlock_irqrestore(&mac->lock, flags);
 256
 257                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 258                         /* reset the retry counter for the next user request since we
 259                          * break out and don't reschedule ourselves after this point. */
 260                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 261                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 262                         return;
 263                 }
 264         }
 265
 266         /* reset the retry counter for the next user request since we
 267          * now found a net and will try to associate to it, but not
 268          * schedule this function again. */
 269         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
 270         mac->associnfo.bssvalid = 1;
 271         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 272         /* copy the ESSID for displaying it */
 273         mac->associnfo.associate_essid.len = found->essid.len;
 274         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 275
 276         /* we found a network! authenticate (if necessary) and associate to it. */
 277         if (!found->authenticated) {
 278                 /* This relies on the fact that _auth_req only queues the work,
 279                  * otherwise adding the notification would be racy. */
 280                 if (!ieee80211softmac_auth_req(mac, found)) {
 281                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 282                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 283                 } else {
 284                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 285                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 286                 }
 287                 return;
 288         }
 289         /* finally! now we can start associating */
 290         ieee80211softmac_assoc(mac, found);
 291 }
 292
 293 /* call this to do whatever is necessary when we're associated */
 294 static void
 295 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 296         struct ieee80211_assoc_response * resp,
 297         struct ieee80211softmac_network *net)
 298 {
 299         mac->associnfo.associating = 0;
 300         mac->associated = 1;
 301         if (mac->set_bssid_filter)
 302                 mac->set_bssid_filter(mac->dev, net->bssid);
 303         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 304         netif_carrier_on(mac->dev);
 305
 306         mac->association_id = le16_to_cpup(&resp->aid);
 307 }
 308
 309 /* received frame handling functions */
 310 int
 311 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 312                                        struct ieee80211_assoc_response * resp,
 313                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 314 {
 315         /* NOTE: the network parameter has to be ignored by
 316          *       this code because it is the ieee80211's pointer
 317          *       to the struct, not ours (we made a copy)
 318          */
 319         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 320         u16 status = le16_to_cpup(&resp->status);
 321         struct ieee80211softmac_network *network = NULL;
 322         unsigned long flags;
 323
 324         if (unlikely(!mac->running))
 325                 return -ENODEV;
 326
 327         spin_lock_irqsave(&mac->lock, flags);
 328
 329         if (!mac->associnfo.associating) {
 330                 /* we race against the timeout function, so make sure
 331                  * only one of us can do work */
 332                 spin_unlock_irqrestore(&mac->lock, flags);
 333                 return 0;
 334         }
 335         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 336
 337         /* someone sending us things without us knowing him? Ignore. */
 338         if (!network) {
 339                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 340                 spin_unlock_irqrestore(&mac->lock, flags);
 341                 return 0;
 342         }
 343
 344         /* now that we know it was for us, we can cancel the timeout */
 345         cancel_delayed_work(&mac->associnfo.timeout);
 346
 347         switch (status) {
 348                 case 0:
 349                         dprintk(KERN_INFO PFX "associated!\n");
 350                         ieee80211softmac_associated(mac, resp, network);
 351                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 352                         break;
 353                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 354                         if (!network->auth_desynced_once) {
 355                                 /* there seem to be a few rare cases where our view of
 356                                  * the world is obscured, or buggy APs that don't DEAUTH
 357                                  * us properly. So we handle that, but allow it only once.
 358                                  */
 359                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 360                                 network->authenticated = 0;
 361                                 /* we don't want to do this more than once ... */
 362                                 network->auth_desynced_once = 1;
 363                                 schedule_work(&mac->associnfo.work);
 364                                 break;
 365                         }
 366                 default:
 367                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 368                         mac->associnfo.associating = 0;
 369                         mac->associnfo.bssvalid = 0;
 370                         mac->associated = 0;
 371                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 372         }
 373
 374         spin_unlock_irqrestore(&mac->lock, flags);
 375         return 0;
 376 }
 377
 378 int
 379 ieee80211softmac_handle_disassoc(struct net_device * dev,
 380                                  struct ieee80211_disassoc *disassoc)
 381 {
 382         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 383         unsigned long flags;
 384
 385         if (unlikely(!mac->running))
 386                 return -ENODEV;
 387
 388         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 389                 return 0;
 390
 391         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 392                 return 0;
 393
 394         dprintk(KERN_INFO PFX "got disassoc frame\n");
 395         netif_carrier_off(dev);
 396         spin_lock_irqsave(&mac->lock, flags);
 397         mac->associnfo.bssvalid = 0;
 398         mac->associated = 0;
 399         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
 400         schedule_work(&mac->associnfo.work);
 401         spin_unlock_irqrestore(&mac->lock, flags);
 402
 403         return 0;
 404 }
 405
 406 int
 407 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
 408                                     struct ieee80211_reassoc_request * resp)
 409 {
 410         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 411         struct ieee80211softmac_network *network;
 412
 413         if (unlikely(!mac->running))
 414                 return -ENODEV;
 415
 416         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
 417         if (!network) {
 418                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
 419                 return 0;
 420         }
 421         schedule_work(&mac->associnfo.work);
 422
 423         return 0;
 424 }