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 */
 168         if (!found)
 169         {
 170                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
 171                                    because it cannot follow the best pointer logic. */
 172                 spin_lock_irqsave(&mac->ieee->lock, flags);
 173                 list_for_each_entry(net, &mac->ieee->network_list, list) {
 174                         /* we're supposed to find the network with
 175                          * the best signal here, as we're asked to join
 176                          * any network with a specific ESSID, and many
 177                          * different ones could have that.
 178                          *
 179                          * I'll for now just go with the reported rssi.
 180                          *
 181                          * We also should take into account the rateset
 182                          * here to find the best BSSID to try.
 183                          */
 184                         if (network_matches_request(mac, net)) {
 185                                 if (!best) {
 186                                         best = net;
 187                                         rssi = best->stats.rssi;
 188                                         continue;
 189                                 }
 190                                 /* we already had a matching network, so
 191                                  * compare their properties to get the
 192                                  * better of the two ... (see above)
 193                                  */
 194                                 if (rssi < net->stats.rssi) {
 195                                         best = net;
 196                                         rssi = best->stats.rssi;
 197                                 }
 198                         }
 199                 }
 200                 /* if we unlock here, we might get interrupted and the `best'
 201                  * pointer could go stale */
 202                 if (best) {
 203                         found = ieee80211softmac_create_network(mac, best);
 204                         /* if found is still NULL, then we got -ENOMEM somewhere */
 205                         if (found)
 206                                 ieee80211softmac_add_network(mac, found);
 207                 }
 208                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
 209         }
 210
 211         if (!found) {
 212                 if (mac->associnfo.scan_retry > 0) {
 213                         spin_lock_irqsave(&mac->lock, flags);
 214                         mac->associnfo.scan_retry--;
 215                         spin_unlock_irqrestore(&mac->lock, flags);
 216
 217                         /* We know of no such network. Let's scan.
 218                          * NB: this also happens if we had no memory to copy the network info...
 219                          * Maybe we can hope to have more memory after scanning finishes ;)
 220                          */
 221                         dprintk(KERN_INFO PFX "Associate: Network not known, trying to initiate scan: ");
 222                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
 223                         if (ieee80211softmac_start_scan(mac))
 224                                 dprintk("failed.\n");
 225                         else
 226                                 dprintk("ok.\n");
 227                         return;
 228                 }
 229                 else {
 230                         spin_lock_irqsave(&mac->lock, flags);
 231                         mac->associnfo.associating = 0;
 232                         mac->associated = 0;
 233                         spin_unlock_irqrestore(&mac->lock, flags);
 234
 235                         dprintk(KERN_INFO PFX "Unable to find network after scan!\n");
 236                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
 237                         return;
 238                 }
 239         }
 240
 241         mac->associnfo.bssvalid = 1;
 242         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
 243         /* copy the ESSID for displaying it */
 244         mac->associnfo.associate_essid.len = found->essid.len;
 245         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
 246
 247         /* we found a network! authenticate (if necessary) and associate to it. */
 248         if (!found->authenticated) {
 249                 /* This relies on the fact that _auth_req only queues the work,
 250                  * otherwise adding the notification would be racy. */
 251                 if (!ieee80211softmac_auth_req(mac, found)) {
 252                         dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
 253                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
 254                 } else {
 255                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
 256                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
 257                 }
 258                 return;
 259         }
 260         /* finally! now we can start associating */
 261         ieee80211softmac_assoc(mac, found);
 262 }
 263
 264 /* call this to do whatever is necessary when we're associated */
 265 static void
 266 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
 267         struct ieee80211_assoc_response * resp,
 268         struct ieee80211softmac_network *net)
 269 {
 270         mac->associnfo.associating = 0;
 271         mac->associated = 1;
 272         if (mac->set_bssid_filter)
 273                 mac->set_bssid_filter(mac->dev, net->bssid);
 274         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
 275         netif_carrier_on(mac->dev);
 276
 277         mac->association_id = le16_to_cpup(&resp->aid);
 278 }
 279
 280 /* received frame handling functions */
 281 int
 282 ieee80211softmac_handle_assoc_response(struct net_device * dev,
 283                                        struct ieee80211_assoc_response * resp,
 284                                        struct ieee80211_network * _ieee80211_network_do_not_use)
 285 {
 286         /* NOTE: the network parameter has to be ignored by
 287          *       this code because it is the ieee80211's pointer
 288          *       to the struct, not ours (we made a copy)
 289          */
 290         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 291         u16 status = le16_to_cpup(&resp->status);
 292         struct ieee80211softmac_network *network = NULL;
 293         unsigned long flags;
 294
 295         spin_lock_irqsave(&mac->lock, flags);
 296
 297         if (!mac->associnfo.associating) {
 298                 /* we race against the timeout function, so make sure
 299                  * only one of us can do work */
 300                 spin_unlock_irqrestore(&mac->lock, flags);
 301                 return 0;
 302         }
 303         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
 304
 305         /* someone sending us things without us knowing him? Ignore. */
 306         if (!network) {
 307                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
 308                 spin_unlock_irqrestore(&mac->lock, flags);
 309                 return 0;
 310         }
 311
 312         /* now that we know it was for us, we can cancel the timeout */
 313         cancel_delayed_work(&mac->associnfo.timeout);
 314
 315         switch (status) {
 316                 case 0:
 317                         dprintk(KERN_INFO PFX "associated!\n");
 318                         ieee80211softmac_associated(mac, resp, network);
 319                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
 320                         break;
 321                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
 322                         if (!network->auth_desynced_once) {
 323                                 /* there seem to be a few rare cases where our view of
 324                                  * the world is obscured, or buggy APs that don't DEAUTH
 325                                  * us properly. So we handle that, but allow it only once.
 326                                  */
 327                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
 328                                 network->authenticated = 0;
 329                                 /* we don't want to do this more than once ... */
 330                                 network->auth_desynced_once = 1;
 331                                 schedule_work(&mac->associnfo.work);
 332                                 break;
 333                         }
 334                 default:
 335                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
 336                         mac->associnfo.associating = 0;
 337                         mac->associnfo.bssvalid = 0;
 338                         mac->associated = 0;
 339                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
 340         }
 341
 342         spin_unlock_irqrestore(&mac->lock, flags);
 343         return 0;
 344 }
 345
 346 int
 347 ieee80211softmac_handle_disassoc(struct net_device * dev,
 348                                  struct ieee80211_disassoc *disassoc)
 349 {
 350         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
 351         unsigned long flags;
 352         /* FIXME: check that this frame is from the right AP!! */
 353         dprintk(KERN_INFO PFX "got disassoc frame\n");
 354         netif_carrier_off(dev);
 355         spin_lock_irqsave(&mac->lock, flags);
 356         mac->associnfo.bssvalid = 0;
 357         mac->associated = 0;
 358         schedule_work(&mac->associnfo.work);
 359         spin_unlock_irqrestore(&mac->lock, flags);
 360
 361         return 0;
 362 }