aboutsummaryrefslogtreecommitdiffstats
path: root/net/ieee80211/softmac/ieee80211softmac_assoc.c
blob: b29fb1cc72c6efb8f209e3196374214a9f1df5c7 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
/*
 * This file contains the softmac's association logic.
 *
 * Copyright (c) 2005 Johannes Berg <johannes@sipsolutions.net>
 *                    Joseph Jezak <josejx@gentoo.org>
 *                    Larry Finger <Larry.Finger@lwfinger.net>
 *                    Danny van Dyk <kugelfang@gentoo.org>
 *                    Michael Buesch <mbuesch@freenet.de>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * The full GNU General Public License is included in this distribution in the
 * file called COPYING.
 */

#include "ieee80211softmac_priv.h"

/*
 * Overview
 *
 * Before you can associate, you have to authenticate.
 * 
 */

/* Sends out an association request to the desired AP */
static void
ieee80211softmac_assoc(struct ieee80211softmac_device *mac, struct ieee80211softmac_network *net)
{
	unsigned long flags;
	function_enter();
	/* Switch to correct channel for this network */
	mac->set_channel(mac->dev, net->channel);
	
	/* Send association request */
	ieee80211softmac_send_mgt_frame(mac, net, IEEE80211_STYPE_ASSOC_REQ, 0);
	
	dprintk(KERN_INFO PFX "sent association request!\n");

	/* Change the state to associating */
	spin_lock_irqsave(&mac->lock, flags);
	mac->associnfo.associating = 1;
	mac->associated = 0; /* just to make sure */
	spin_unlock_irqrestore(&mac->lock, flags);

	/* Set a timer for timeout */
	/* FIXME: make timeout configurable */
	schedule_delayed_work(&mac->associnfo.timeout, 5 * HZ);
}

void
ieee80211softmac_assoc_timeout(void *d)
{
	struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
	unsigned long flags;

	function_enter();

	spin_lock_irqsave(&mac->lock, flags);
	/* we might race against ieee80211softmac_handle_assoc_response,
	 * so make sure only one of us does something */
	if (!mac->associnfo.associating) {
		spin_unlock_irqrestore(&mac->lock, flags);
		return;
	}
	mac->associnfo.associating = 0;
	mac->associnfo.bssvalid = 0;
	mac->associated = 0;
	spin_unlock_irqrestore(&mac->lock, flags);

	dprintk(KERN_INFO PFX "assoc request timed out!\n");
	/* FIXME: we need to know the network here. that requires a bit of restructuring */
	ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_TIMEOUT, NULL);
}

static void
ieee80211softmac_reassoc(struct ieee80211softmac_device *mac)
{
	function_enter();
}


/* Sends out a disassociation request to the desired AP */
static void
ieee80211softmac_disassoc(struct ieee80211softmac_device *mac, u16 reason)
{
	unsigned long flags;
	struct ieee80211softmac_network *found;
	function_enter();

	if (mac->associnfo.bssvalid && mac->associated) {
		found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);
		if (found)
			ieee80211softmac_send_mgt_frame(mac, found, IEEE80211_STYPE_DISASSOC, reason);
	} else if (mac->associnfo.associating) {
		cancel_delayed_work(&mac->associnfo.timeout);
	}

	/* Change our state */
	spin_lock_irqsave(&mac->lock, flags);
	/* Do NOT clear bssvalid as that will break ieee80211softmac_assoc_work! */
	mac->associated = 0;
	mac->associnfo.associating = 0;
	spin_unlock_irqrestore(&mac->lock, flags);
}

static inline int
we_support_all_basic_rates(struct ieee80211softmac_device *mac, u8 *from, u8 from_len)
{
	int idx, search, found;
	u8 rate, search_rate;

	for (idx = 0; idx < (from_len); idx++) {
		rate = (from)[idx];
		if (!(rate & IEEE80211_BASIC_RATE_MASK))
			continue;
		found = 0;
		rate &= ~IEEE80211_BASIC_RATE_MASK;
		for (search = 0; search < mac->ratesinfo.count; search++) {
			search_rate = mac->ratesinfo.rates[search];
			search_rate &= ~IEEE80211_BASIC_RATE_MASK;
			if (rate == search_rate) {
				found = 1;
				break;
			}
		}
		if (!found)
			return 0;
	}
	return 1;
}

static int
network_matches_request(struct ieee80211softmac_device *mac, struct ieee80211_network *net)
{
	/* we cannot associate to networks whose name we don't know */
	if (ieee80211_is_empty_essid(net->ssid, net->ssid_len))
		return 0;
	/* do not associate to a network whose BSSBasicRateSet we cannot support */
	if (!we_support_all_basic_rates(mac, net->rates, net->rates_len))
		return 0;
	/* do we really need to check the ex rates? */
	if (!we_support_all_basic_rates(mac, net->rates_ex, net->rates_ex_len))
		return 0;

	/* if 'ANY' network requested, take any that doesn't have privacy enabled */
	if (mac->associnfo.req_essid.len == 0 
	    && !(net->capability & WLAN_CAPABILITY_PRIVACY))
		return 1;
	if (net->ssid_len != mac->associnfo.req_essid.len)
		return 0;
	if (!memcmp(net->ssid, mac->associnfo.req_essid.data, mac->associnfo.req_essid.len))
		return 1;
	return 0;
}

static void
ieee80211softmac_assoc_notify(struct net_device *dev, void *context)
{
	struct ieee80211softmac_device *mac = ieee80211_priv(dev);
	ieee80211softmac_assoc_work((void*)mac);
}

/* This function is called to handle userspace requests (asynchronously) */
void
ieee80211softmac_assoc_work(void *d)
{
	struct ieee80211softmac_device *mac = (struct ieee80211softmac_device *)d;
	struct ieee80211softmac_network *found = NULL;
	struct ieee80211_network *net = NULL, *best = NULL;
	unsigned long flags;
	
	function_enter();
	
	/* meh */
	if (mac->associated)
		ieee80211softmac_disassoc(mac, WLAN_REASON_DISASSOC_STA_HAS_LEFT);

	/* try to find the requested network in our list, if we found one already */
	if (mac->associnfo.bssvalid)
		found = ieee80211softmac_get_network_by_bssid(mac, mac->associnfo.bssid);	
	
	/* Search the ieee80211 networks for this network if we didn't find it by bssid,
	 * but only if we've scanned at least once (to get a better list of networks to
	 * select from). If we have not scanned before, the !found logic below will be
	 * invoked and will scan. */
	if (!found && (mac->associnfo.scan_retry < IEEE80211SOFTMAC_ASSOC_SCAN_RETRY_LIMIT))
	{
		s8 rssi = -128;	/* if I don't initialise, gcc emits an invalid warning
				   because it cannot follow the best pointer logic. */
		spin_lock_irqsave(&mac->ieee->lock, flags);
		list_for_each_entry(net, &mac->ieee->network_list, list) {
			/* we're supposed to find the network with
			 * the best signal here, as we're asked to join
			 * any network with a specific ESSID, and many
			 * different ones could have that.
			 *
			 * I'll for now just go with the reported rssi.
			 *
			 * We also should take into account the rateset
			 * here to find the best BSSID to try.
			 */
			if (network_matches_request(mac, net)) {
				if (!best) {
					best = net;
					rssi = best->stats.rssi;
					continue;
				}
				/* we already had a matching network, so
				 * compare their properties to get the
				 * better of the two ... (see above)
				 */
				if (rssi < net->stats.rssi) {
					best = net;
					rssi = best->stats.rssi;
				}
			}
		}
		/* if we unlock here, we might get interrupted and the `best'
		 * pointer could go stale */
		if (best) {
			found = ieee80211softmac_create_network(mac, best);
			/* if found is still NULL, then we got -ENOMEM somewhere */
			if (found)
				ieee80211softmac_add_network(mac, found);
		}
		spin_unlock_irqrestore(&mac->ieee->lock, flags);
	}

	if (!found) {
		if (mac->associnfo.scan_retry > 0) {
			spin_lock_irqsave(&mac->lock, flags);
			mac->associnfo.scan_retry--;
			spin_unlock_irqrestore(&mac->lock, flags);
		
			/* We know of no such network. Let's scan. 
			 * NB: this also happens if we had no memory to copy the network info...
			 * Maybe we can hope to have more memory after scanning finishes ;)
			 */
			dprintk(KERN_INFO PFX "Associate: Scanning for networks first.\n");
			ieee80211softmac_notify(mac->dev, IEEE80211SOFTMAC_EVENT_SCAN_FINISHED, ieee80211softmac_assoc_notify, NULL);
			if (ieee80211softmac_start_scan(mac))
				dprintk(KERN_INFO PFX "Associate: failed to initiate scan. Is device up?\n");
			return;
		}
		else {
			spin_lock_irqsave(&mac->lock, flags);
			mac->associnfo.associating = 0;
			mac->associated = 0;
			spin_unlock_irqrestore(&mac->lock, flags);

			dprintk(KERN_INFO PFX "Unable to find matching network after scan!\n");
			ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_NET_NOT_FOUND, NULL);
			return;
		}
	}
	
	mac->associnfo.bssvalid = 1;
	memcpy(mac->associnfo.bssid, found->bssid, ETH_ALEN);
	/* copy the ESSID for displaying it */
	mac->associnfo.associate_essid.len = found->essid.len;
	memcpy(mac->associnfo.associate_essid.data, found->essid.data, IW_ESSID_MAX_SIZE + 1);
	
	/* we found a network! authenticate (if necessary) and associate to it. */
	if (!found->authenticated) {
		/* This relies on the fact that _auth_req only queues the work,
		 * otherwise adding the notification would be racy. */
		if (!ieee80211softmac_auth_req(mac, found)) {
			dprintk(KERN_INFO PFX "cannot associate without being authenticated, requested authentication\n");
			ieee80211softmac_notify_internal(mac, IEEE80211SOFTMAC_EVENT_ANY, found, ieee80211softmac_assoc_notify, NULL, GFP_KERNEL);
		} else {
			printkl(KERN_WARNING PFX "Not authenticated, but requesting authentication failed. Giving up to associate\n");
			ieee80211softmac_call_events(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, found);
		}
		return;
	}
	/* finally! now we can start associating */
	ieee80211softmac_assoc(mac, found);
}

/* call this to do whatever is necessary when we're associated */
static void
ieee80211softmac_associated(struct ieee80211softmac_device *mac,
	struct ieee80211_assoc_response * resp,
	struct ieee80211softmac_network *net)
{
	mac->associnfo.associating = 0;
	mac->associated = 1;
	if (mac->set_bssid_filter)
		mac->set_bssid_filter(mac->dev, net->bssid);
	memcpy(mac->ieee->bssid, net->bssid, ETH_ALEN);
	netif_carrier_on(mac->dev);
	
	mac->association_id = le16_to_cpup(&resp->aid);
}

/* received frame handling functions */
int
ieee80211softmac_handle_assoc_response(struct net_device * dev,
				       struct ieee80211_assoc_response * resp,
				       struct ieee80211_network * _ieee80211_network_do_not_use)
{
	/* NOTE: the network parameter has to be ignored by
	 *       this code because it is the ieee80211's pointer
	 *       to the struct, not ours (we made a copy)
	 */
	struct ieee80211softmac_device *mac = ieee80211_priv(dev);
	u16 status = le16_to_cpup(&resp->status);
	struct ieee80211softmac_network *network = NULL;
	unsigned long flags;
	
	spin_lock_irqsave(&mac->lock, flags);

	if (!mac->associnfo.associating) {
		/* we race against the timeout function, so make sure
		 * only one of us can do work */
		spin_unlock_irqrestore(&mac->lock, flags);
		return 0;
	}
	network = ieee80211softmac_get_network_by_bssid_locked(mac, resp->header.addr3);

	/* someone sending us things without us knowing him? Ignore. */
	if (!network) {
		dprintk(KERN_INFO PFX "Received unrequested assocation response from " MAC_FMT "\n", MAC_ARG(resp->header.addr3));
		spin_unlock_irqrestore(&mac->lock, flags);
		return 0;
	}

	/* now that we know it was for us, we can cancel the timeout */
	cancel_delayed_work(&mac->associnfo.timeout);

	switch (status) {
		case 0:
			dprintk(KERN_INFO PFX "associated!\n");
			ieee80211softmac_associated(mac, resp, network);
			ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATED, network);
			break;
		case WLAN_REASON_STA_REQ_ASSOC_WITHOUT_AUTH:
			if (!network->auth_desynced_once) {
				/* there seem to be a few rare cases where our view of
				 * the world is obscured, or buggy APs that don't DEAUTH
				 * us properly. So we handle that, but allow it only once.
				 */
				printkl(KERN_INFO PFX "We were not authenticated during association, retrying...\n");
				network->authenticated = 0;
				/* we don't want to do this more than once ... */
				network->auth_desynced_once = 1;
				schedule_work(&mac->associnfo.work);
				break;
			}
		default:
			dprintk(KERN_INFO PFX "associating failed (reason: 0x%x)!\n", status);
			mac->associnfo.associating = 0;
			mac->associnfo.bssvalid = 0;
			mac->associated = 0;
			ieee80211softmac_call_events_locked(mac, IEEE80211SOFTMAC_EVENT_ASSOCIATE_FAILED, network);
	}
	
	spin_unlock_irqrestore(&mac->lock, flags);
	return 0;
}

int
ieee80211softmac_handle_disassoc(struct net_device * dev,
				 struct ieee80211_disassoc *disassoc)
{
	struct ieee80211softmac_device *mac = ieee80211_priv(dev);
	unsigned long flags;
	if (memcmp(disassoc->header.addr2, mac->associnfo.bssid, ETH_ALEN))
		return 0;
	if (memcmp(disassoc->header.addr1, mac->dev->dev_addr, ETH_ALEN))
		return 0;
	dprintk(KERN_INFO PFX "got disassoc frame\n");
	netif_carrier_off(dev);
	spin_lock_irqsave(&mac->lock, flags);
	mac->associnfo.bssvalid = 0;
	mac->associated = 0;
	schedule_work(&mac->associnfo.work);
	spin_unlock_irqrestore(&mac->lock, flags);
	
	return 0;
}