Merge branch 'linux-2.6' into for-2.6.24
[linux-2.6] / 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         spin_lock_irqsave(&mac->lock, flags);
51         mac->associnfo.associated = 0; /* just to make sure */
52
53         /* Set a timer for timeout */
54         /* FIXME: make timeout configurable */
55         if (likely(mac->running))
56                 schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
57         spin_unlock_irqrestore(&mac->lock, flags);
58 }
59
60 void
61 ieee80211softmac_assoc_timeout(struct work_struct *work)
62 {
63         struct ieee80211softmac_device *mac =
64                 container_of(work, struct ieee80211softmac_device,
65                              associnfo.timeout.work);
66         struct ieee80211softmac_network *n;
67
68         mutex_lock(&mac->associnfo.mutex);
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                 goto out;
73         mac->associnfo.associating = 0;
74         mac->associnfo.bssvalid = 0;
75         mac->associnfo.associated = 0;
76
77         n = ieee80211softmac_get_network_by_bssid_locked(mac, mac->associnfo.bssid);
78
79         dprintk(KERN_INFO PFX "assoc request timed out!\n");
80         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, n);
81 out:
82         mutex_unlock(&mac->associnfo.mutex);
83 }
84
85 void
86 ieee80211softmac_disassoc(struct ieee80211softmac_device *mac)
87 {
88         unsigned long flags;
89
90         spin_lock_irqsave(&mac->lock, flags);
91         if (mac->associnfo.associating)
92                 cancel_delayed_work(&mac->associnfo.timeout);
93
94         netif_carrier_off(mac->dev);
95
96         mac->associnfo.associated = 0;
97         mac->associnfo.bssvalid = 0;
98         mac->associnfo.associating = 0;
99         ieee80211softmac_init_bss(mac);
100         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_DISASSOCIATED, NULL);
101         spin_unlock_irqrestore(&mac->lock, flags);
102 }
103
104 /* Sends out a disassociation request to the desired AP */
105 void
106 ieee80211softmac_send_disassoc_req(struct ieee80211softmac_device *mac, u16 reason)
107 {
108         struct ieee80211softmac_network *found;
109
110         if (mac->associnfo.bssvalid && mac->associnfo.associated) {
111                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
112                 if (found)
113                         ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
114         }
115
116         ieee80211softmac_disassoc(mac);
117 }
118
119 static inline int
120 we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
121 {
122         int idx;
123         u8 rate;
124
125         for (idx = 0; idx < (from_len); idx++) {
126                 rate = (from)[idx];
127                 if (!(rate & IEEE80211_BASIC_RATE_MASK))
128                         continue;
129                 rate &= ~IEEE80211_BASIC_RATE_MASK;
130                 if (!ieee80211softmac_ratesinfo_rate_supported(&mac->ratesinfo, rate))
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         /* assume that users know what they're doing ...
150          * (note we don't let them select a net we're incompatible with) */
151         if (mac->associnfo.bssfixed) {
152                 return !memcmp(mac->associnfo.bssid, net->bssid, ETH_ALEN);
153         }
154
155         /* if 'ANY' network requested, take any that doesn't have privacy enabled */
156         if (mac->associnfo.req_essid.len == 0
157             && !(net->capability & WLAN_CAPABILITY_PRIVACY))
158                 return 1;
159         if (net->ssid_len != mac->associnfo.req_essid.len)
160                 return 0;
161         if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
162                 return 1;
163         return 0;
164 }
165
166 static void
167 ieee80211softmac_assoc_notify_scan(struct net_device *dev, int event_type, void *context)
168 {
169         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
170         ieee80211softmac_assoc_work(&mac->associnfo.work.work);
171 }
172
173 static void
174 ieee80211softmac_assoc_notify_auth(struct net_device *dev, int event_type, void *context)
175 {
176         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
177
178         switch (event_type) {
179         case IEEE80211SOFTMAC_EVENT_AUTHENTICATED:
180                 ieee80211softmac_assoc_work(&mac->associnfo.work.work);
181                 break;
182         case IEEE80211SOFTMAC_EVENT_AUTH_FAILED:
183         case IEEE80211SOFTMAC_EVENT_AUTH_TIMEOUT:
184                 ieee80211softmac_disassoc(mac);
185                 break;
186         }
187 }
188
189 /* This function is called to handle userspace requests (asynchronously) */
190 void
191 ieee80211softmac_assoc_work(struct work_struct *work)
192 {
193         struct ieee80211softmac_device *mac =
194                 container_of(work, struct ieee80211softmac_device,
195                              associnfo.work.work);
196         struct ieee80211softmac_network *found = NULL;
197         struct ieee80211_network *net = NULL, *best = NULL;
198         int bssvalid;
199         unsigned long flags;
200
201         mutex_lock(&mac->associnfo.mutex);
202
203         if (!mac->associnfo.associating)
204                 goto out;
205
206         /* ieee80211_disassoc might clear this */
207         bssvalid = mac->associnfo.bssvalid;
208
209         /* meh */
210         if (mac->associnfo.associated)
211                 ieee80211softmac_send_disassoc_req(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);
212
213         /* try to find the requested network in our list, if we found one already */
214         if (bssvalid || mac->associnfo.bssfixed)
215                 found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
216
217         /* Search the ieee80211 networks for this network if we didn't find it by bssid,
218          * but only if we've scanned at least once (to get a better list of networks to
219          * select from). If we have not scanned before, the !found logic below will be
220          * invoked and will scan. */
221         if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
222         {
223                 s8 rssi = -128; /* if I don't initialise, gcc emits an invalid warning
224                                    because it cannot follow the best pointer logic. */
225                 spin_lock_irqsave(&mac->ieee->lock, flags);
226                 list_for_each_entry(net, &mac->ieee->network_list, list) {
227                         /* we're supposed to find the network with
228                          * the best signal here, as we're asked to join
229                          * any network with a specific ESSID, and many
230                          * different ones could have that.
231                          *
232                          * I'll for now just go with the reported rssi.
233                          *
234                          * We also should take into account the rateset
235                          * here to find the best BSSID to try.
236                          */
237                         if (network_matches_request(mac, net)) {
238                                 if (!best) {
239                                         best = net;
240                                         rssi = best->stats.rssi;
241                                         continue;
242                                 }
243                                 /* we already had a matching network, so
244                                  * compare their properties to get the
245                                  * better of the two ... (see above)
246                                  */
247                                 if (rssi < net->stats.rssi) {
248                                         best = net;
249                                         rssi = best->stats.rssi;
250                                 }
251                         }
252                 }
253                 /* if we unlock here, we might get interrupted and the `best'
254                  * pointer could go stale */
255                 if (best) {
256                         found = ieee80211softmac_create_network(mac, best);
257                         /* if found is still NULL, then we got -ENOMEM somewhere */
258                         if (found)
259                                 ieee80211softmac_add_network(mac, found);
260                 }
261                 spin_unlock_irqrestore(&mac->ieee->lock, flags);
262         }
263
264         if (!found) {
265                 if (mac->associnfo.scan_retry > 0) {
266                         mac->associnfo.scan_retry--;
267
268                         /* We know of no such network. Let's scan.
269                          * NB: this also happens if we had no memory to copy the network info...
270                          * Maybe we can hope to have more memory after scanning finishes ;)
271                          */
272                         dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
273                         ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify_scan, NULL);
274                         if (ieee80211softmac_start_scan(mac)) {
275                                 dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
276                         }
277                         goto out;
278                 } else {
279                         mac->associnfo.associating = 0;
280                         mac->associnfo.associated = 0;
281
282                         dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
283                         /* reset the retry counter for the next user request since we
284                          * break out and don't reschedule ourselves after this point. */
285                         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
286                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
287                         goto out;
288                 }
289         }
290
291         /* reset the retry counter for the next user request since we
292          * now found a net and will try to associate to it, but not
293          * schedule this function again. */
294         mac->associnfo.scan_retry = IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT;
295         mac->associnfo.bssvalid = 1;
296         memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
297         /* copy the ESSID for displaying it */
298         mac->associnfo.associate_essid.len = found->essid.len;
299         memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
300
301         /* we found a network! authenticate (if necessary) and associate to it. */
302         if (found->authenticating) {
303                 dprintk(KERN_INFO PFX "Already requested authentication, waiting...\n");
304                 if(!mac->associnfo.assoc_wait) {
305                         mac->associnfo.assoc_wait = 1;
306                         ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
307                 }
308                 goto out;
309         }
310         if (!found->authenticated && !found->authenticating) {
311                 /* This relies on the fact that _auth_req only queues the work,
312                  * otherwise adding the notification would be racy. */
313                 if (!ieee80211softmac_auth_req(mac, found)) {
314                         if(!mac->associnfo.assoc_wait) {
315                                 dprintk(KERN_INFO PFX "Cannot associate without being authenticated, requested authentication\n");
316                                 mac->associnfo.assoc_wait = 1;
317                                 ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify_auth, NULL, GFP_KERNEL);
318                         }
319                 } else {
320                         printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
321                         mac->associnfo.assoc_wait = 0;
322                         ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
323                 }
324                 goto out;
325         }
326         /* finally! now we can start associating */
327         mac->associnfo.assoc_wait = 0;
328         ieee80211softmac_assoc(mac, found);
329
330 out:
331         mutex_unlock(&mac->associnfo.mutex);
332 }
333
334 /* call this to do whatever is necessary when we're associated */
335 static void
336 ieee80211softmac_associated(struct ieee80211softmac_device *mac,
337         struct ieee80211_assoc_response * resp,
338         struct ieee80211softmac_network *net)
339 {
340         u16 cap = le16_to_cpu(resp->capability);
341         u8 erp_value = net->erp_value;
342
343         mac->associnfo.associating = 0;
344         mac->bssinfo.supported_rates = net->supported_rates;
345         ieee80211softmac_recalc_txrates(mac);
346
347         mac->associnfo.associated = 1;
348
349         mac->associnfo.short_preamble_available =
350                 (cap & WLAN_CAPABILITY_SHORT_PREAMBLE) != 0;
351         ieee80211softmac_process_erp(mac, erp_value);
352
353         if (mac->set_bssid_filter)
354                 mac->set_bssid_filter(mac->dev, net->bssid);
355         memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
356         netif_carrier_on(mac->dev);
357
358         mac->association_id = le16_to_cpup(&resp->aid);
359 }
360
361 /* received frame handling functions */
362 int
363 ieee80211softmac_handle_assoc_response(struct net_device * dev,
364                                        struct ieee80211_assoc_response * resp,
365                                        struct ieee80211_network * _ieee80211_network)
366 {
367         /* NOTE: the network parameter has to be mostly ignored by
368          *       this code because it is the ieee80211's pointer
369          *       to the struct, not ours (we made a copy)
370          */
371         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
372         u16 status = le16_to_cpup(&resp->status);
373         struct ieee80211softmac_network *network = NULL;
374         unsigned long flags;
375
376         if (unlikely(!mac->running))
377                 return -ENODEV;
378
379         spin_lock_irqsave(&mac->lock, flags);
380
381         if (!mac->associnfo.associating) {
382                 /* we race against the timeout function, so make sure
383                  * only one of us can do work */
384                 spin_unlock_irqrestore(&mac->lock, flags);
385                 return 0;
386         }
387         network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);
388
389         /* someone sending us things without us knowing him? Ignore. */
390         if (!network) {
391                 dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
392                 spin_unlock_irqrestore(&mac->lock, flags);
393                 return 0;
394         }
395
396         /* now that we know it was for us, we can cancel the timeout */
397         cancel_delayed_work(&mac->associnfo.timeout);
398
399         /* if the association response included an ERP IE, update our saved
400          * copy */
401         if (_ieee80211_network->flags & NETWORK_HAS_ERP_VALUE)
402                 network->erp_value = _ieee80211_network->erp_value;
403
404         switch (status) {
405                 case 0:
406                         dprintk(KERN_INFO PFX "associated!\n");
407                         ieee80211softmac_associated(mac, resp, network);
408                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
409                         break;
410                 case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
411                         if (!network->auth_desynced_once) {
412                                 /* there seem to be a few rare cases where our view of
413                                  * the world is obscured, or buggy APs that don't DEAUTH
414                                  * us properly. So we handle that, but allow it only once.
415                                  */
416                                 printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
417                                 network->authenticated = 0;
418                                 /* we don't want to do this more than once ... */
419                                 network->auth_desynced_once = 1;
420                                 schedule_delayed_work(&mac->associnfo.work, 0);
421                                 break;
422                         }
423                 default:
424                         dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
425                         mac->associnfo.associating = 0;
426                         mac->associnfo.bssvalid = 0;
427                         mac->associnfo.associated = 0;
428                         ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
429         }
430
431         spin_unlock_irqrestore(&mac->lock, flags);
432         return 0;
433 }
434
435 void
436 ieee80211softmac_try_reassoc(struct ieee80211softmac_device *mac)
437 {
438         unsigned long flags;
439
440         spin_lock_irqsave(&mac->lock, flags);
441         mac->associnfo.associating = 1;
442         schedule_delayed_work(&mac->associnfo.work, 0);
443         spin_unlock_irqrestore(&mac->lock, flags);
444 }
445
446 int
447 ieee80211softmac_handle_disassoc(struct net_device * dev,
448                                  struct ieee80211_disassoc *disassoc)
449 {
450         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
451
452         if (unlikely(!mac->running))
453                 return -ENODEV;
454
455         if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
456                 return 0;
457
458         if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
459                 return 0;
460
461         dprintk(KERN_INFO PFX "got disassoc frame\n");
462         ieee80211softmac_disassoc(mac);
463
464         ieee80211softmac_try_reassoc(mac);
465
466         return 0;
467 }
468
469 int
470 ieee80211softmac_handle_reassoc_req(struct net_device * dev,
471                                     struct ieee80211_reassoc_request * resp)
472 {
473         struct ieee80211softmac_device *mac = ieee80211_priv(dev);
474         struct ieee80211softmac_network *network;
475
476         if (unlikely(!mac->running))
477                 return -ENODEV;
478
479         network = ieee80211softmac_get_network_by_bssid(mac, resp->header.addr3);
480         if (!network) {
481                 dprintkl(KERN_INFO PFX "reassoc request from unknown network\n");
482                 return 0;
483         }
484         schedule_delayed_work(&mac->associnfo.work, 0);
485
486         return 0;
487 }