net/ieee80211/softmac/ieee80211softmac_assoc.c

   1 #include "ieee80211softmac_priv.h"
   2
   3 /*
   4  * Overview
   5  *
   6  * Before you can associate, you have to authenticate.
   7  *
   8  */
   9
  10 /* Sends out an association request to the desired AP */
  11 static void
  12 ieee80211softmac_assoc(struct ieee80211softmac_device *mac, struct ieee80211softmac_network *net)
  13 {
  14         unsigned long flags;
  15         function_enter();
  16         /* Switch to correct channel for this network */
  17         mac->set_channel(mac->dev, net->channel);
  18
  19         /* Send association request */
  20         ieee80211softmac_send_mgt_frame(mac, net, IEEE80211_STYPE_ASSOC_REQ, 0);
  21
  22         dprintk(KERN_INFO PFX "sent association request!\n");
  23
  24         /* Change the state to associating */
  25         spin_lock_irqsave(&mac->lock, flags);
  26         mac->associnfo.associating = 1;
  27         mac->associated = 0; /* just to make sure */
  28         spin_unlock_irqrestore(&mac->lock, flags);
  29
  30         /* Set a timer for timeout */
  31         /* FIXME: make timeout configurable */
  32         schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
  33 }
  34
  35 void
  36 ieee80211softmac_assoc_timeout(void *d)
  37 {
  38         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
  39         unsigned long flags;
  40
  41         function_enter();
  42
  43         spin_lock_irqsave(&mac->lock, flags);
  44         /* we might race against ieee80211softmac_handle_assoc_response,
  45          * so make sure only one of us does something */
  46         if (!mac->associnfo.associating) {
  47                 spin_unlock_irqrestore(&mac->lock, flags);
  48                 return;
  49         }
  50         mac->associnfo.associating = 0;
  51         mac->associnfo.bssvalid = 0;
  52         mac->associated = 0;
  53         spin_unlock_irqrestore(&mac->lock, flags);
  54
  55         dprintk(KERN_INFO PFX "assoc request timed out!\n");
  56         /* FIXME: we need to know the network here. that requires a bit of restructuring */
  57         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
  58 }
  59
  60 static void
  61 ieee80211softmac_reassoc(struct ieee80211softmac_device *mac)
  62 {
  63         function_enter();
  64 }
  65
  66
  67 /* Sends out a disassociation request to the desired AP */
  68 static void
  69 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
  70 {
  71         unsigned long flags;
  72         struct ieee80211softmac_network *found;
  73         function_enter();
  74
  75         if (mac->associnfo.bssvalid && mac->associated) {
  76                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
  77                 if (found)
  78                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
  79         } else if (mac->associnfo.associating) {
  80                 cancel_delayed_work(&mac->associnfo.timeout);
  81         }
  82
  83         /* Change our state */
  84         spin_lock_irqsave(&mac->lock, flags);
  85         /* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
  86         mac->associated = 0;
  87         mac->associnfo.associating = 0;
  88         spin_unlock_irqrestore(&mac->lock, flags);
  89 }
  90
  91 static inline int
  92 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
  93 {
  94         int idx, search, found;
  95         u8 rate, search_rate;
  96
  97         for (idx = 0; idx < (from_len); idx++) {
  98                 rate = (from)[idx];
  99                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
 100                         continue;
 101                 found = 0;
 102                 rate &= ~IEEE80211_BASIC_RATE_MASK;
 103                 for (search = 0; search < mac->ratesinfo.count; search++) {
 104                         search_rate = mac->ratesinfo.rates[search];
 105                         search_rate &= ~IEEE80211_BASIC_RATE_MASK;
 106                         if (rate == search_rate) {
 107                                 found = 1;
 108                                 break;
 109                         }
 110                 }
 111                 if (!found)
 112                         return 0;
 113         }
 114         return 1;
 115 }
 116
 117 static int
 118 network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
 119 {
 120         /* we cannot associate to networks whose name we don't know */
 121         if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
 122                 return 0;
 123         /* do not associate to a network whose BSSBasicRateSet we cannot support */
 124         if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
 125                 return 0;
 126         /* do we really need to check the ex rates? */
 127         if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
 128                 return 0;
 129
 130         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
 131         if (mac->associnfo.req_essid.len == 0
 132             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
 133                 return 1;
 134         if (net->ssid_len != mac->associnfo.req_essid.len)
 135                 return 0;
 136         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
 137                 return 1;
 138         return 0;
 139 }
 140
 141 static void
 142 ieee80211softmac_assoc_notify(struct net_device *dev, void *context)
 143 {
 144         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 145         ieee80211softmac_assoc_work((void*)mac);
 146 }
 147
 148 /* This function is called to handle userspace requests (asynchronously) */
 149 void
 150 ieee80211softmac_assoc_work(void *d)
 151 {
 152         struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
 153         struct ieee80211softmac_network *found = NULL;
 154         struct ieee80211_network *net = NULL, *best = NULL;
 155         unsigned long flags;
 156
 157         function_enter();
 158
 159         /* meh */
 160         if (mac->associated)
 161                 ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
 162
 163         /* try to find the requested network in our list, if we found one already */
 164         if (mac->associnfo.bssvalid)
 165                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
 166
 167         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
 168          * but only if we've scanned at least once (to get a better list of networks to
 169          * select from). If we have not scanned before, the !found logic below will be
 170          * invoked and will scan. */
 171         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
 172         {
 173                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 174                                    because it cannot follow the best pointer logic. */
 175                 spin_lock_irqsave(&mac->ieee->lock, flags);
 176                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 177                         /* we're supposed to find the network with
 178                          * the best signal here, as we're asked to join
 179                          * any network with a specific ESSID, and many
 180                          * different ones could have that.
 181                          *
 182                          * I'll for now just go with the reported rssi.
 183                          *
 184                          * We also should take into account the rateset
 185                          * here to find the best BSSID to try.
 186                          */
 187                         if (network_matches_request(mac, net)) {
 188                                 if (!best) {
 189                                         best = net;
 190                                         rssi = best->stats.rssi;
 191                                         continue;
 192                                 }
 193                                 /* we already had a matching network, so
 194                                  * compare their properties to get the
 195                                  * better of the two ... (see above)
 196                                  */
 197                                 if (rssi < net->stats.rssi) {
 198                                         best = net;
 199                                         rssi = best->stats.rssi;
 200                                 }
 201                         }
 202                 }
 203                 /* if we unlock here, we might get interrupted and the `best'
 204                  * pointer could go stale */
 205                 if (best) {
 206                         found = ieee80211softmac_create_network(mac, best);
 207                         /* if found is still NULL, then we got -ENOMEM somewhere */
 208                         if (found)
 209                                 ieee80211softmac_add_network(mac, found);
 210                 }
 211                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 212         }
 213
 214         if (!found) {
 215                 if (mac->associnfo.scan_retry > 0) {
 216                         spin_lock_irqsave(&mac->lock, flags);
 217                         mac->associnfo.scan_retry--;
 218                         spin_unlock_irqrestore(&mac->lock, flags);
 219
 220                         /* We know of no such network. Let's scan.
 221                          * NB: this also happens if we had no memory to copy the network info...
 222                          * Maybe we can hope to have more memory after scanning finishes ;)
 223                          */
 224                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
 225                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 226                         if (ieee80211softmac_start_scan(mac))
 227                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
 228                         return;
 229                 }
 230                 else {
 231                         spin_lock_irqsave(&mac->lock, flags);
 232                         mac->associnfo.associating = 0;
 233                         mac->associated = 0;
 234                         spin_unlock_irqrestore(&mac->lock, flags);
 235
 236                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
 237                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 238                         return;
 239                 }
 240         }
 241
 242         mac->associnfo.bssvalid = 1;
 243         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 244         /* copy the ESSID for displaying it */
 245         mac->associnfo.associate_essid.len = found->essid.len;
 246         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 247
 248         /* we found a network! authenticate (if necessary) and associate to it. */
 249         if (!found->authenticated) {
 250                 /* This relies on the fact that _auth_req only queues the work,
 251                  * otherwise adding the notification would be racy. */
 252                 if (!ieee80211softmac_auth_req(mac, found)) {
 253                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 254                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 255                 } else {
 256                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 257                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 258                 }
 259                 return;
 260         }
 261         /* finally! now we can start associating */
 262         ieee80211softmac_assoc(mac, found);
 263 }
 264
 265 /* call this to do whatever is necessary when we're associated */
 266 static void
 267 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 268         struct ieee80211_assoc_response * resp,
 269         struct ieee80211softmac_network *net)
 270 {
 271         mac->associnfo.associating = 0;
 272         mac->associated = 1;
 273         if (mac->set_bssid_filter)
 274                 mac->set_bssid_filter(mac->dev, net->bssid);
 275         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 276         netif_carrier_on(mac->dev);
 277
 278         mac->association_id = le16_to_cpup(&resp->aid);
 279 }
 280
 281 /* received frame handling functions */
 282 int
 283 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 284                                        struct ieee80211_assoc_response * resp,
 285                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 286 {
 287         /* NOTE: the network parameter has to be ignored by
 288          *       this code because it is the ieee80211's pointer
 289          *       to the struct, not ours (we made a copy)
 290          */
 291         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 292         u16 status = le16_to_cpup(&resp->status);
 293         struct ieee80211softmac_network *network = NULL;
 294         unsigned long flags;
 295
 296         spin_lock_irqsave(&mac->lock, flags);
 297
 298         if (!mac->associnfo.associating) {
 299                 /* we race against the timeout function, so make sure
 300                  * only one of us can do work */
 301                 spin_unlock_irqrestore(&mac->lock, flags);
 302                 return 0;
 303         }
 304         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 305
 306         /* someone sending us things without us knowing him? Ignore. */
 307         if (!network) {
 308                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 309                 spin_unlock_irqrestore(&mac->lock, flags);
 310                 return 0;
 311         }
 312
 313         /* now that we know it was for us, we can cancel the timeout */
 314         cancel_delayed_work(&mac->associnfo.timeout);
 315
 316         switch (status) {
 317                 case 0:
 318                         dprintk(KERN_INFO PFX "associated!\n");
 319                         ieee80211softmac_associated(mac, resp, network);
 320                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 321                         break;
 322                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 323                         if (!network->auth_desynced_once) {
 324                                 /* there seem to be a few rare cases where our view of
 325                                  * the world is obscured, or buggy APs that don't DEAUTH
 326                                  * us properly. So we handle that, but allow it only once.
 327                                  */
 328                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 329                                 network->authenticated = 0;
 330                                 /* we don't want to do this more than once ... */
 331                                 network->auth_desynced_once = 1;
 332                                 schedule_work(&mac->associnfo.work);
 333                                 break;
 334                         }
 335                 default:
 336                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 337                         mac->associnfo.associating = 0;
 338                         mac->associnfo.bssvalid = 0;
 339                         mac->associated = 0;
 340                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 341         }
 342
 343         spin_unlock_irqrestore(&mac->lock, flags);
 344         return 0;
 345 }
 346
 347 int
 348 ieee80211softmac_handle_disassoc(struct net_device * dev,
 349                                  struct ieee80211_disassoc *disassoc)
 350 {
 351         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 352         unsigned long flags;
 353         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
 354                 return 0;
 355         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
 356                 return 0;
 357         dprintk(KERN_INFO PFX "got disassoc frame\n");
 358         netif_carrier_off(dev);
 359         spin_lock_irqsave(&mac->lock, flags);
 360         mac->associnfo.bssvalid = 0;
 361         mac->associated = 0;
 362         schedule_work(&mac->associnfo.work);
 363         spin_unlock_irqrestore(&mac->lock, flags);
 364
 365         return 0;
 366 }