xref: /freebsd/sys/net80211/ieee80211_node.c (revision 0f8f86b71f022b803e99151c19db81b280f245dc)
1 /*-
2  * Copyright (c) 2001 Atsushi Onoe
3  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * Alternatively, this software may be distributed under the terms of the
18  * GNU General Public License ("GPL") version 2 as published by the Free
19  * Software Foundation.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  */
32 
33 #include <sys/cdefs.h>
34 __FBSDID("$FreeBSD$");
35 
36 #include "opt_inet.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/malloc.h>
42 #include <sys/kernel.h>
43 #include <sys/socket.h>
44 #include <sys/sockio.h>
45 #include <sys/endian.h>
46 #include <sys/errno.h>
47 #include <sys/bus.h>
48 #include <sys/proc.h>
49 #include <sys/sysctl.h>
50 
51 #include <machine/atomic.h>
52 
53 #include <net/if.h>
54 #include <net/if_dl.h>
55 #include <net/if_media.h>
56 #include <net/if_arp.h>
57 #include <net/ethernet.h>
58 #include <net/if_llc.h>
59 
60 #include <net80211/ieee80211_var.h>
61 
62 #include <net/bpf.h>
63 
64 #ifdef INET
65 #include <netinet/in.h>
66 #include <netinet/if_ether.h>
67 #endif
68 
69 static struct ieee80211_node *ieee80211_node_alloc(struct ieee80211com *);
70 static void ieee80211_node_free(struct ieee80211com *, struct ieee80211_node *);
71 static void ieee80211_node_copy(struct ieee80211com *,
72 		struct ieee80211_node *, const struct ieee80211_node *);
73 static u_int8_t ieee80211_node_getrssi(struct ieee80211com *,
74 		struct ieee80211_node *);
75 
76 static void ieee80211_setup_node(struct ieee80211com *ic,
77 		struct ieee80211_node *ni, u_int8_t *macaddr);
78 static void _ieee80211_free_node(struct ieee80211com *,
79 		struct ieee80211_node *);
80 
81 MALLOC_DEFINE(M_80211_NODE, "node", "802.11 node state");
82 
83 void
84 ieee80211_node_attach(struct ifnet *ifp)
85 {
86 	struct ieee80211com *ic = (void *)ifp;
87 
88 	/* XXX need unit */
89 	IEEE80211_NODE_LOCK_INIT(ic, ifp->if_xname);
90 	TAILQ_INIT(&ic->ic_node);
91 	ic->ic_node_alloc = ieee80211_node_alloc;
92 	ic->ic_node_free = ieee80211_node_free;
93 	ic->ic_node_copy = ieee80211_node_copy;
94 	ic->ic_node_getrssi = ieee80211_node_getrssi;
95 	ic->ic_scangen = 1;
96 }
97 
98 void
99 ieee80211_node_lateattach(struct ifnet *ifp)
100 {
101 	struct ieee80211com *ic = (void *)ifp;
102 
103 	ic->ic_bss = (*ic->ic_node_alloc)(ic);
104 	KASSERT(ic->ic_bss != NULL, ("unable to setup inital BSS node"));
105 	ic->ic_bss->ni_chan = IEEE80211_CHAN_ANYC;
106 }
107 
108 void
109 ieee80211_node_detach(struct ifnet *ifp)
110 {
111 	struct ieee80211com *ic = (void *)ifp;
112 
113 	if (ic->ic_bss != NULL)
114 		(*ic->ic_node_free)(ic, ic->ic_bss);
115 	ieee80211_free_allnodes(ic);
116 	IEEE80211_NODE_LOCK_DESTROY(ic);
117 }
118 
119 /*
120  * AP scanning support.
121  */
122 
123 /*
124  * Initialize the active channel set based on the set
125  * of available channels and the current PHY mode.
126  */
127 static void
128 ieee80211_reset_scan(struct ifnet *ifp)
129 {
130 	struct ieee80211com *ic = (void *)ifp;
131 
132 	memcpy(ic->ic_chan_scan, ic->ic_chan_active,
133 		sizeof(ic->ic_chan_active));
134 	/* NB: hack, setup so next_scan starts with the first channel */
135 	if (ic->ic_bss->ni_chan == IEEE80211_CHAN_ANYC)
136 		ic->ic_bss->ni_chan = &ic->ic_channels[IEEE80211_CHAN_MAX];
137 }
138 
139 /*
140  * Begin an active scan.
141  */
142 void
143 ieee80211_begin_scan(struct ifnet *ifp)
144 {
145 	struct ieee80211com *ic = (void *)ifp;
146 
147 	/*
148 	 * In all but hostap mode scanning starts off in
149 	 * an active mode before switching to passive.
150 	 */
151 	if (ic->ic_opmode != IEEE80211_M_HOSTAP) {
152 		ic->ic_flags |= IEEE80211_F_ASCAN;
153 		ic->ic_stats.is_scan_active++;
154 	} else
155 		ic->ic_stats.is_scan_passive++;
156 	if (ifp->if_flags & IFF_DEBUG)
157 		if_printf(ifp, "begin %s scan\n",
158 			(ic->ic_flags & IEEE80211_F_ASCAN) ?
159 				"active" : "passive");
160 	/*
161 	 * Clear scan state and flush any previously seen
162 	 * AP's.  Note that the latter assumes we don't act
163 	 * as both an AP and a station, otherwise we'll
164 	 * potentially flush state of stations associated
165 	 * with us.
166 	 */
167 	ieee80211_reset_scan(ifp);
168 	ieee80211_free_allnodes(ic);
169 
170 	/* Scan the next channel. */
171 	ieee80211_next_scan(ifp);
172 }
173 
174 /*
175  * Switch to the next channel marked for scanning.
176  */
177 void
178 ieee80211_next_scan(struct ifnet *ifp)
179 {
180 	struct ieee80211com *ic = (void *)ifp;
181 	struct ieee80211_channel *chan;
182 
183 	chan = ic->ic_bss->ni_chan;
184 	for (;;) {
185 		if (++chan > &ic->ic_channels[IEEE80211_CHAN_MAX])
186 			chan = &ic->ic_channels[0];
187 		if (isset(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan))) {
188 			/*
189 			 * Honor channels marked passive-only
190 			 * during an active scan.
191 			 */
192 			if ((ic->ic_flags & IEEE80211_F_ASCAN) == 0 ||
193 			    (chan->ic_flags & IEEE80211_CHAN_PASSIVE) == 0)
194 				break;
195 		}
196 		if (chan == ic->ic_bss->ni_chan) {
197 			ieee80211_end_scan(ifp);
198 			return;
199 		}
200 	}
201 	clrbit(ic->ic_chan_scan, ieee80211_chan2ieee(ic, chan));
202 	IEEE80211_DPRINTF(("ieee80211_next_scan: chan %d->%d\n",
203 	    ieee80211_chan2ieee(ic, ic->ic_bss->ni_chan),
204 	    ieee80211_chan2ieee(ic, chan)));
205 	ic->ic_bss->ni_chan = chan;
206 	ieee80211_new_state(ic, IEEE80211_S_SCAN, -1);
207 }
208 
209 void
210 ieee80211_create_ibss(struct ieee80211com* ic, struct ieee80211_channel *chan)
211 {
212 	struct ieee80211_node *ni;
213 	struct ifnet *ifp = &ic->ic_if;
214 
215 	ni = ic->ic_bss;
216 	if (ifp->if_flags & IFF_DEBUG)
217 		if_printf(ifp, "creating ibss\n");
218 	ic->ic_flags |= IEEE80211_F_SIBSS;
219 	ni->ni_chan = chan;
220 	ni->ni_rates = ic->ic_sup_rates[ieee80211_chan2mode(ic, ni->ni_chan)];
221 	IEEE80211_ADDR_COPY(ni->ni_macaddr, ic->ic_myaddr);
222 	IEEE80211_ADDR_COPY(ni->ni_bssid, ic->ic_myaddr);
223 	if (ic->ic_opmode == IEEE80211_M_IBSS)
224 		ni->ni_bssid[0] |= 0x02;	/* local bit for IBSS */
225 	ni->ni_esslen = ic->ic_des_esslen;
226 	memcpy(ni->ni_essid, ic->ic_des_essid, ni->ni_esslen);
227 	ni->ni_rssi = 0;
228 	ni->ni_rstamp = 0;
229 	memset(ni->ni_tstamp, 0, sizeof(ni->ni_tstamp));
230 	ni->ni_intval = ic->ic_lintval;
231 	ni->ni_capinfo = IEEE80211_CAPINFO_IBSS;
232 	if (ic->ic_flags & IEEE80211_F_WEPON)
233 		ni->ni_capinfo |= IEEE80211_CAPINFO_PRIVACY;
234 	if (ic->ic_phytype == IEEE80211_T_FH) {
235 		ni->ni_fhdwell = 200;	/* XXX */
236 		ni->ni_fhindex = 1;
237 	}
238 	ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
239 }
240 
241 /*
242  * Complete a scan of potential channels.
243  */
244 void
245 ieee80211_end_scan(struct ifnet *ifp)
246 {
247 	struct ieee80211com *ic = (void *)ifp;
248 	struct ieee80211_node *ni, *nextbs, *selbs;
249 	u_int8_t rate;
250 	int i, fail;
251 
252 	ic->ic_flags &= ~IEEE80211_F_ASCAN;
253 	ni = TAILQ_FIRST(&ic->ic_node);
254 
255 	if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
256 		/* XXX off stack? */
257 		u_char occupied[roundup(IEEE80211_CHAN_MAX, NBBY)];
258 		/*
259 		 * The passive scan to look for existing AP's completed,
260 		 * select a channel to camp on.  Identify the channels
261 		 * that already have one or more AP's and try to locate
262 		 * an unnoccupied one.  If that fails, pick a random
263 		 * channel from the active set.
264 		 */
265 		for (; ni != NULL; ni = nextbs) {
266 			ieee80211_ref_node(ni);
267 			nextbs = TAILQ_NEXT(ni, ni_list);
268 			setbit(occupied, ieee80211_chan2ieee(ic, ni->ni_chan));
269 			ieee80211_free_node(ic, ni);
270 		}
271 		for (i = 0; i < IEEE80211_CHAN_MAX; i++)
272 			if (isset(ic->ic_chan_active, i) && isclr(occupied, i))
273 				break;
274 		if (i == IEEE80211_CHAN_MAX) {
275 			fail = arc4random() & 3;	/* random 0-3 */
276 			for (i = 0; i < IEEE80211_CHAN_MAX; i++)
277 				if (isset(ic->ic_chan_active, i) && fail-- == 0)
278 					break;
279 		}
280 		ieee80211_create_ibss(ic, &ic->ic_channels[i]);
281 		return;
282 	}
283 	if (ni == NULL) {
284 		IEEE80211_DPRINTF(("%s: no scan candidate\n", __func__));
285   notfound:
286 		if (ic->ic_opmode == IEEE80211_M_IBSS &&
287 		    (ic->ic_flags & IEEE80211_F_IBSSON) &&
288 		    ic->ic_des_esslen != 0) {
289 			ieee80211_create_ibss(ic, ic->ic_ibss_chan);
290 			return;
291 		}
292 		/*
293 		 * Reset the list of channels to scan and start again.
294 		 */
295 		ieee80211_reset_scan(ifp);
296 		ieee80211_next_scan(ifp);
297 		return;
298 	}
299 	selbs = NULL;
300 	if (ifp->if_flags & IFF_DEBUG)
301 		if_printf(ifp, "\tmacaddr          bssid         chan  rssi rate flag  wep  essid\n");
302 	for (; ni != NULL; ni = nextbs) {
303 		ieee80211_ref_node(ni);
304 		nextbs = TAILQ_NEXT(ni, ni_list);
305 		if (ni->ni_fails) {
306 			/*
307 			 * The configuration of the access points may change
308 			 * during my scan.  So delete the entry for the AP
309 			 * and retry to associate if there is another beacon.
310 			 */
311 			if (ni->ni_fails++ > 2)
312 				ieee80211_free_node(ic, ni);
313 			continue;
314 		}
315 		fail = 0;
316 		if (isclr(ic->ic_chan_active, ieee80211_chan2ieee(ic, ni->ni_chan)))
317 			fail |= 0x01;
318 		if (ic->ic_des_chan != IEEE80211_CHAN_ANYC &&
319 		    ni->ni_chan != ic->ic_des_chan)
320 			fail |= 0x01;
321 		if (ic->ic_opmode == IEEE80211_M_IBSS) {
322 			if ((ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) == 0)
323 				fail |= 0x02;
324 		} else {
325 			if ((ni->ni_capinfo & IEEE80211_CAPINFO_ESS) == 0)
326 				fail |= 0x02;
327 		}
328 		if (ic->ic_flags & IEEE80211_F_WEPON) {
329 			if ((ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) == 0)
330 				fail |= 0x04;
331 		} else {
332 			if (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY)
333 				fail |= 0x04;
334 		}
335 		rate = ieee80211_fix_rate(ic, ni, IEEE80211_F_DONEGO);
336 		if (rate & IEEE80211_RATE_BASIC)
337 			fail |= 0x08;
338 		if (ic->ic_des_esslen != 0 &&
339 		    (ni->ni_esslen != ic->ic_des_esslen ||
340 		     memcmp(ni->ni_essid, ic->ic_des_essid, ic->ic_des_esslen) != 0))
341 			fail |= 0x10;
342 		if ((ic->ic_flags & IEEE80211_F_DESBSSID) &&
343 		    !IEEE80211_ADDR_EQ(ic->ic_des_bssid, ni->ni_bssid))
344 			fail |= 0x20;
345 		if (ifp->if_flags & IFF_DEBUG) {
346 			printf(" %c %s", fail ? '-' : '+',
347 			    ether_sprintf(ni->ni_macaddr));
348 			printf(" %s%c", ether_sprintf(ni->ni_bssid),
349 			    fail & 0x20 ? '!' : ' ');
350 			printf(" %3d%c", ieee80211_chan2ieee(ic, ni->ni_chan),
351 				fail & 0x01 ? '!' : ' ');
352 			printf(" %+4d", ni->ni_rssi);
353 			printf(" %2dM%c", (rate & IEEE80211_RATE_VAL) / 2,
354 			    fail & 0x08 ? '!' : ' ');
355 			printf(" %4s%c",
356 			    (ni->ni_capinfo & IEEE80211_CAPINFO_ESS) ? "ess" :
357 			    (ni->ni_capinfo & IEEE80211_CAPINFO_IBSS) ? "ibss" :
358 			    "????",
359 			    fail & 0x02 ? '!' : ' ');
360 			printf(" %3s%c ",
361 			    (ni->ni_capinfo & IEEE80211_CAPINFO_PRIVACY) ?
362 			    "wep" : "no",
363 			    fail & 0x04 ? '!' : ' ');
364 			ieee80211_print_essid(ni->ni_essid, ni->ni_esslen);
365 			printf("%s\n", fail & 0x10 ? "!" : "");
366 		}
367 		if (!fail) {
368 			if (selbs == NULL)
369 				selbs = ni;
370 			else if (ni->ni_rssi > selbs->ni_rssi) {
371 				ieee80211_unref_node(&selbs);
372 				selbs = ni;
373 			} else
374 				ieee80211_unref_node(&ni);
375 		} else {
376 			ieee80211_unref_node(&ni);
377 		}
378 	}
379 	if (selbs == NULL)
380 		goto notfound;
381 	(*ic->ic_node_copy)(ic, ic->ic_bss, selbs);
382 	if (ic->ic_opmode == IEEE80211_M_IBSS) {
383 		ieee80211_fix_rate(ic, ic->ic_bss, IEEE80211_F_DOFRATE |
384 		    IEEE80211_F_DONEGO | IEEE80211_F_DODEL);
385 		if (ic->ic_bss->ni_rates.rs_nrates == 0) {
386 			selbs->ni_fails++;
387 			ieee80211_unref_node(&selbs);
388 			goto notfound;
389 		}
390 		ieee80211_unref_node(&selbs);
391 		ieee80211_new_state(ic, IEEE80211_S_RUN, -1);
392 	} else {
393 		ieee80211_unref_node(&selbs);
394 		ieee80211_new_state(ic, IEEE80211_S_AUTH, -1);
395 	}
396 }
397 
398 static struct ieee80211_node *
399 ieee80211_node_alloc(struct ieee80211com *ic)
400 {
401 	return malloc(sizeof(struct ieee80211_node), M_80211_NODE,
402 		M_NOWAIT | M_ZERO);
403 }
404 
405 static void
406 ieee80211_node_free(struct ieee80211com *ic, struct ieee80211_node *ni)
407 {
408 	free(ni, M_80211_NODE);
409 }
410 
411 static void
412 ieee80211_node_copy(struct ieee80211com *ic,
413 	struct ieee80211_node *dst, const struct ieee80211_node *src)
414 {
415 	*dst = *src;
416 }
417 
418 static u_int8_t
419 ieee80211_node_getrssi(struct ieee80211com *ic, struct ieee80211_node *ni)
420 {
421 	return ni->ni_rssi;
422 }
423 
424 static void
425 ieee80211_setup_node(struct ieee80211com *ic,
426 	struct ieee80211_node *ni, u_int8_t *macaddr)
427 {
428 	int hash;
429 
430 	IEEE80211_ADDR_COPY(ni->ni_macaddr, macaddr);
431 	hash = IEEE80211_NODE_HASH(macaddr);
432 	ni->ni_refcnt = 1;		/* mark referenced */
433 	IEEE80211_NODE_LOCK(ic);
434 	TAILQ_INSERT_TAIL(&ic->ic_node, ni, ni_list);
435 	LIST_INSERT_HEAD(&ic->ic_hash[hash], ni, ni_hash);
436 	/*
437 	 * Note we don't enable the inactive timer when acting
438 	 * as a station.  Nodes created in this mode represent
439 	 * AP's identified while scanning.  If we time them out
440 	 * then several things happen: we can't return the data
441 	 * to users to show the list of AP's we encountered, and
442 	 * more importantly, we'll incorrectly deauthenticate
443 	 * ourself because the inactivity timer will kick us off.
444 	 */
445 	if (ic->ic_opmode != IEEE80211_M_STA)
446 		ic->ic_inact_timer = IEEE80211_INACT_WAIT;
447 	IEEE80211_NODE_UNLOCK(ic);
448 }
449 
450 struct ieee80211_node *
451 ieee80211_alloc_node(struct ieee80211com *ic, u_int8_t *macaddr)
452 {
453 	struct ieee80211_node *ni = (*ic->ic_node_alloc)(ic);
454 	if (ni != NULL)
455 		ieee80211_setup_node(ic, ni, macaddr);
456 	return ni;
457 }
458 
459 struct ieee80211_node *
460 ieee80211_dup_bss(struct ieee80211com *ic, u_int8_t *macaddr)
461 {
462 	struct ieee80211_node *ni = (*ic->ic_node_alloc)(ic);
463 	if (ni != NULL) {
464 		memcpy(ni, ic->ic_bss, sizeof(struct ieee80211_node));
465 		ieee80211_setup_node(ic, ni, macaddr);
466 	}
467 	return ni;
468 }
469 
470 struct ieee80211_node *
471 ieee80211_find_node(struct ieee80211com *ic, u_int8_t *macaddr)
472 {
473 	struct ieee80211_node *ni;
474 	int hash;
475 
476 	hash = IEEE80211_NODE_HASH(macaddr);
477 	IEEE80211_NODE_LOCK(ic);
478 	LIST_FOREACH(ni, &ic->ic_hash[hash], ni_hash) {
479 		if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr)) {
480 			atomic_add_int(&ni->ni_refcnt, 1); /* mark referenced */
481 			break;
482 		}
483 	}
484 	IEEE80211_NODE_UNLOCK(ic);
485 	return ni;
486 }
487 
488 /*
489  * Like find but search based on the channel too.
490  */
491 struct ieee80211_node *
492 ieee80211_lookup_node(struct ieee80211com *ic,
493 	u_int8_t *macaddr, struct ieee80211_channel *chan)
494 {
495 	struct ieee80211_node *ni;
496 	int hash;
497 
498 	hash = IEEE80211_NODE_HASH(macaddr);
499 	IEEE80211_NODE_LOCK(ic);
500 	LIST_FOREACH(ni, &ic->ic_hash[hash], ni_hash) {
501 		if (IEEE80211_ADDR_EQ(ni->ni_macaddr, macaddr) && ni->ni_chan == chan) {
502 			atomic_add_int(&ni->ni_refcnt, 1);/* mark referenced */
503 			break;
504 		}
505 	}
506 	IEEE80211_NODE_UNLOCK(ic);
507 	return ni;
508 }
509 
510 static void
511 _ieee80211_free_node(struct ieee80211com *ic, struct ieee80211_node *ni)
512 {
513 	KASSERT(ni != ic->ic_bss, ("freeing bss node"));
514 
515 	TAILQ_REMOVE(&ic->ic_node, ni, ni_list);
516 	LIST_REMOVE(ni, ni_hash);
517 	if (TAILQ_EMPTY(&ic->ic_node))
518 		ic->ic_inact_timer = 0;
519 	(*ic->ic_node_free)(ic, ni);
520 }
521 
522 void
523 ieee80211_free_node(struct ieee80211com *ic, struct ieee80211_node *ni)
524 {
525 	KASSERT(ni != ic->ic_bss, ("freeing ic_bss"));
526 
527 	/* XXX need equivalent of atomic_dec_and_test */
528 	atomic_subtract_int(&ni->ni_refcnt, 1);
529 	if (atomic_cmpset_int(&ni->ni_refcnt, 0, 1)) {
530 		IEEE80211_NODE_LOCK(ic);
531 		_ieee80211_free_node(ic, ni);
532 		IEEE80211_NODE_UNLOCK(ic);
533 	}
534 }
535 
536 void
537 ieee80211_free_allnodes(struct ieee80211com *ic)
538 {
539 	struct ieee80211_node *ni;
540 
541 	IEEE80211_NODE_LOCK(ic);
542 	while ((ni = TAILQ_FIRST(&ic->ic_node)) != NULL)
543 		_ieee80211_free_node(ic, ni);
544 	IEEE80211_NODE_UNLOCK(ic);
545 }
546 
547 /*
548  * Timeout inactive nodes.  Note that we cannot hold the node
549  * lock while sending a frame as this would lead to a LOR.
550  * Instead we use a generation number to mark nodes that we've
551  * scanned and drop the lock and restart a scan if we have to
552  * time out a node.  Since we are single-threaded by virtue of
553  * controlling the inactivity timer we can be sure this will
554  * process each node only once.
555  */
556 void
557 ieee80211_timeout_nodes(struct ieee80211com *ic)
558 {
559 	struct ieee80211_node *ni;
560 	u_int gen = ic->ic_scangen++;		/* NB: ok 'cuz single-threaded*/
561 
562 restart:
563 	IEEE80211_NODE_LOCK(ic);
564 	TAILQ_FOREACH(ni, &ic->ic_node, ni_list) {
565 		if (ni->ni_scangen == gen)	/* previously handled */
566 			continue;
567 		ni->ni_scangen = gen;
568 		if (++ni->ni_inact > IEEE80211_INACT_MAX) {
569 			IEEE80211_DPRINTF(("station %s timed out "
570 			    "due to inactivity (%u secs)\n",
571 			    ether_sprintf(ni->ni_macaddr),
572 			    ni->ni_inact));
573 			/*
574 			 * Send a deauthenticate frame.
575 			 *
576 			 * Drop the node lock before sending the
577 			 * deauthentication frame in case the driver takes
578 			 * a lock, as this will result in a LOR between the
579 			 * node lock and the driver lock.
580 			 */
581 			IEEE80211_NODE_UNLOCK(ic);
582 			IEEE80211_SEND_MGMT(ic, ni,
583 			    IEEE80211_FC0_SUBTYPE_DEAUTH,
584 			    IEEE80211_REASON_AUTH_EXPIRE);
585 			ieee80211_free_node(ic, ni);
586 			ic->ic_stats.is_node_timeout++;
587 			goto restart;
588 		}
589 	}
590 	if (!TAILQ_EMPTY(&ic->ic_node))
591 		ic->ic_inact_timer = IEEE80211_INACT_WAIT;
592 	IEEE80211_NODE_UNLOCK(ic);
593 }
594 
595 void
596 ieee80211_iterate_nodes(struct ieee80211com *ic, ieee80211_iter_func *f, void *arg)
597 {
598 	struct ieee80211_node *ni;
599 
600 	IEEE80211_NODE_LOCK(ic);
601 	TAILQ_FOREACH(ni, &ic->ic_node, ni_list)
602 		(*f)(arg, ni);
603 	IEEE80211_NODE_UNLOCK(ic);
604 }
605