xref: /freebsd/sys/net80211/ieee80211_power.c (revision 2710751bc309af25c6dea1171781678258e83840)
1 /*-
2  * Copyright (c) 2002-2008 Sam Leffler, Errno Consulting
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms, with or without
6  * modification, are permitted provided that the following conditions
7  * are met:
8  * 1. Redistributions of source code must retain the above copyright
9  *    notice, this list of conditions and the following disclaimer.
10  * 2. Redistributions in binary form must reproduce the above copyright
11  *    notice, this list of conditions and the following disclaimer in the
12  *    documentation and/or other materials provided with the distribution.
13  *
14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24  */
25 
26 #include <sys/cdefs.h>
27 __FBSDID("$FreeBSD$");
28 
29 /*
30  * IEEE 802.11 power save support.
31  */
32 #include "opt_wlan.h"
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/kernel.h>
37 
38 #include <sys/socket.h>
39 
40 #include <net/if.h>
41 #include <net/if_media.h>
42 #include <net/ethernet.h>
43 
44 #include <net80211/ieee80211_var.h>
45 
46 #include <net/bpf.h>
47 
48 static void ieee80211_update_ps(struct ieee80211vap *, int);
49 static int ieee80211_set_tim(struct ieee80211_node *, int);
50 
51 static MALLOC_DEFINE(M_80211_POWER, "80211power", "802.11 power save state");
52 
53 void
54 ieee80211_power_attach(struct ieee80211com *ic)
55 {
56 }
57 
58 void
59 ieee80211_power_detach(struct ieee80211com *ic)
60 {
61 }
62 
63 void
64 ieee80211_power_vattach(struct ieee80211vap *vap)
65 {
66 	if (vap->iv_opmode == IEEE80211_M_HOSTAP ||
67 	    vap->iv_opmode == IEEE80211_M_IBSS) {
68 		/* NB: driver should override */
69 		vap->iv_update_ps = ieee80211_update_ps;
70 		vap->iv_set_tim = ieee80211_set_tim;
71 	}
72 	vap->iv_node_ps = ieee80211_node_pwrsave;
73 	vap->iv_sta_ps = ieee80211_sta_pwrsave;
74 }
75 
76 void
77 ieee80211_power_latevattach(struct ieee80211vap *vap)
78 {
79 	/*
80 	 * Allocate these only if needed.  Beware that we
81 	 * know adhoc mode doesn't support ATIM yet...
82 	 */
83 	if (vap->iv_opmode == IEEE80211_M_HOSTAP) {
84 		vap->iv_tim_len = howmany(vap->iv_max_aid,8) * sizeof(uint8_t);
85 		vap->iv_tim_bitmap = (uint8_t *) malloc(vap->iv_tim_len,
86 			M_80211_POWER, M_NOWAIT | M_ZERO);
87 		if (vap->iv_tim_bitmap == NULL) {
88 			printf("%s: no memory for TIM bitmap!\n", __func__);
89 			/* XXX good enough to keep from crashing? */
90 			vap->iv_tim_len = 0;
91 		}
92 	}
93 }
94 
95 void
96 ieee80211_power_vdetach(struct ieee80211vap *vap)
97 {
98 	if (vap->iv_tim_bitmap != NULL) {
99 		free(vap->iv_tim_bitmap, M_80211_POWER);
100 		vap->iv_tim_bitmap = NULL;
101 	}
102 }
103 
104 void
105 ieee80211_psq_init(struct ieee80211_psq *psq, const char *name)
106 {
107 	memset(psq, 0, sizeof(*psq));
108 	psq->psq_maxlen = IEEE80211_PS_MAX_QUEUE;
109 	IEEE80211_PSQ_INIT(psq, name);		/* OS-dependent setup */
110 }
111 
112 void
113 ieee80211_psq_cleanup(struct ieee80211_psq *psq)
114 {
115 #if 0
116 	psq_drain(psq);				/* XXX should not be needed? */
117 #else
118 	KASSERT(psq->psq_len == 0, ("%d frames on ps q", psq->psq_len));
119 #endif
120 	IEEE80211_PSQ_DESTROY(psq);		/* OS-dependent cleanup */
121 }
122 
123 /*
124  * Return the highest priority frame in the ps queue.
125  */
126 struct mbuf *
127 ieee80211_node_psq_dequeue(struct ieee80211_node *ni, int *qlen)
128 {
129 	struct ieee80211_psq *psq = &ni->ni_psq;
130 	struct ieee80211_psq_head *qhead;
131 	struct mbuf *m;
132 
133 	IEEE80211_PSQ_LOCK(psq);
134 	qhead = &psq->psq_head[0];
135 again:
136 	if ((m = qhead->head) != NULL) {
137 		if ((qhead->head = m->m_nextpkt) == NULL)
138 			qhead->tail = NULL;
139 		KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
140 		qhead->len--;
141 		KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
142 		psq->psq_len--;
143 		m->m_nextpkt = NULL;
144 	}
145 	if (m == NULL && qhead == &psq->psq_head[0]) {
146 		/* Algol-68 style for loop */
147 		qhead = &psq->psq_head[1];
148 		goto again;
149 	}
150 	if (qlen != NULL)
151 		*qlen = psq->psq_len;
152 	IEEE80211_PSQ_UNLOCK(psq);
153 	return m;
154 }
155 
156 /*
157  * Reclaim an mbuf from the ps q.  If marked with M_ENCAP
158  * we assume there is a node reference that must be relcaimed.
159  */
160 static void
161 psq_mfree(struct mbuf *m)
162 {
163 	if (m->m_flags & M_ENCAP) {
164 		struct ieee80211_node *ni = (void *) m->m_pkthdr.rcvif;
165 		ieee80211_free_node(ni);
166 	}
167 	m->m_nextpkt = NULL;
168 	m_freem(m);
169 }
170 
171 /*
172  * Clear any frames queued in the power save queue.
173  * The number of frames that were present is returned.
174  */
175 static int
176 psq_drain(struct ieee80211_psq *psq)
177 {
178 	struct ieee80211_psq_head *qhead;
179 	struct mbuf *m;
180 	int qlen;
181 
182 	IEEE80211_PSQ_LOCK(psq);
183 	qlen = psq->psq_len;
184 	qhead = &psq->psq_head[0];
185 again:
186 	while ((m = qhead->head) != NULL) {
187 		qhead->head = m->m_nextpkt;
188 		psq_mfree(m);
189 	}
190 	qhead->tail = NULL;
191 	qhead->len = 0;
192 	if (qhead == &psq->psq_head[0]) {	/* Algol-68 style for loop */
193 		qhead = &psq->psq_head[1];
194 		goto again;
195 	}
196 	psq->psq_len = 0;
197 	IEEE80211_PSQ_UNLOCK(psq);
198 
199 	return qlen;
200 }
201 
202 /*
203  * Clear any frames queued in the power save queue.
204  * The number of frames that were present is returned.
205  */
206 int
207 ieee80211_node_psq_drain(struct ieee80211_node *ni)
208 {
209 	return psq_drain(&ni->ni_psq);
210 }
211 
212 /*
213  * Age frames on the power save queue. The aging interval is
214  * 4 times the listen interval specified by the station.  This
215  * number is factored into the age calculations when the frame
216  * is placed on the queue.  We store ages as time differences
217  * so we can check and/or adjust only the head of the list.
218  * If a frame's age exceeds the threshold then discard it.
219  * The number of frames discarded is returned so the caller
220  * can check if it needs to adjust the tim.
221  */
222 int
223 ieee80211_node_psq_age(struct ieee80211_node *ni)
224 {
225 	struct ieee80211_psq *psq = &ni->ni_psq;
226 	int discard = 0;
227 
228 	if (psq->psq_len != 0) {
229 #ifdef IEEE80211_DEBUG
230 		struct ieee80211vap *vap = ni->ni_vap;
231 #endif
232 		struct ieee80211_psq_head *qhead;
233 		struct mbuf *m;
234 
235 		IEEE80211_PSQ_LOCK(psq);
236 		qhead = &psq->psq_head[0];
237 	again:
238 		while ((m = qhead->head) != NULL &&
239 		    M_AGE_GET(m) < IEEE80211_INACT_WAIT) {
240 			IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
241 			     "discard frame, age %u", M_AGE_GET(m));
242 			if ((qhead->head = m->m_nextpkt) == NULL)
243 				qhead->tail = NULL;
244 			KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
245 			qhead->len--;
246 			KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
247 			psq->psq_len--;
248 			psq_mfree(m);
249 			discard++;
250 		}
251 		if (qhead == &psq->psq_head[0]) { /* Algol-68 style for loop */
252 			qhead = &psq->psq_head[1];
253 			goto again;
254 		}
255 		if (m != NULL)
256 			M_AGE_SUB(m, IEEE80211_INACT_WAIT);
257 		IEEE80211_PSQ_UNLOCK(psq);
258 
259 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
260 		    "discard %u frames for age", discard);
261 		IEEE80211_NODE_STAT_ADD(ni, ps_discard, discard);
262 	}
263 	return discard;
264 }
265 
266 /*
267  * Handle a change in the PS station occupancy.
268  */
269 static void
270 ieee80211_update_ps(struct ieee80211vap *vap, int nsta)
271 {
272 
273 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
274 		vap->iv_opmode == IEEE80211_M_IBSS,
275 		("operating mode %u", vap->iv_opmode));
276 }
277 
278 /*
279  * Indicate whether there are frames queued for a station in power-save mode.
280  */
281 static int
282 ieee80211_set_tim(struct ieee80211_node *ni, int set)
283 {
284 	struct ieee80211vap *vap = ni->ni_vap;
285 	struct ieee80211com *ic = ni->ni_ic;
286 	uint16_t aid;
287 	int changed;
288 
289 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
290 		vap->iv_opmode == IEEE80211_M_IBSS,
291 		("operating mode %u", vap->iv_opmode));
292 
293 	aid = IEEE80211_AID(ni->ni_associd);
294 	KASSERT(aid < vap->iv_max_aid,
295 		("bogus aid %u, max %u", aid, vap->iv_max_aid));
296 
297 	IEEE80211_LOCK(ic);
298 	changed = (set != (isset(vap->iv_tim_bitmap, aid) != 0));
299 	if (changed) {
300 		if (set) {
301 			setbit(vap->iv_tim_bitmap, aid);
302 			vap->iv_ps_pending++;
303 		} else {
304 			clrbit(vap->iv_tim_bitmap, aid);
305 			vap->iv_ps_pending--;
306 		}
307 		/* NB: we know vap is in RUN state so no need to check */
308 		vap->iv_update_beacon(vap, IEEE80211_BEACON_TIM);
309 	}
310 	IEEE80211_UNLOCK(ic);
311 
312 	return changed;
313 }
314 
315 /*
316  * Save an outbound packet for a node in power-save sleep state.
317  * The new packet is placed on the node's saved queue, and the TIM
318  * is changed, if necessary.
319  */
320 int
321 ieee80211_pwrsave(struct ieee80211_node *ni, struct mbuf *m)
322 {
323 	struct ieee80211_psq *psq = &ni->ni_psq;
324 	struct ieee80211vap *vap = ni->ni_vap;
325 	struct ieee80211com *ic = ni->ni_ic;
326 	struct ieee80211_psq_head *qhead;
327 	int qlen, age;
328 
329 	IEEE80211_PSQ_LOCK(psq);
330 	if (psq->psq_len >= psq->psq_maxlen) {
331 		psq->psq_drops++;
332 		IEEE80211_PSQ_UNLOCK(psq);
333 		IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
334 		    "pwr save q overflow, drops %d (size %d)",
335 		    psq->psq_drops, psq->psq_len);
336 #ifdef IEEE80211_DEBUG
337 		if (ieee80211_msg_dumppkts(vap))
338 			ieee80211_dump_pkt(ni->ni_ic, mtod(m, caddr_t),
339 			    m->m_len, -1, -1);
340 #endif
341 		psq_mfree(m);
342 		return ENOSPC;
343 	}
344 	/*
345 	 * Tag the frame with it's expiry time and insert it in
346 	 * the appropriate queue.  The aging interval is 4 times
347 	 * the listen interval specified by the station. Frames
348 	 * that sit around too long are reclaimed using this
349 	 * information.
350 	 */
351 	/* TU -> secs.  XXX handle overflow? */
352 	age = IEEE80211_TU_TO_MS((ni->ni_intval * ic->ic_bintval) << 2) / 1000;
353 	/*
354 	 * Encapsulated frames go on the high priority queue,
355 	 * other stuff goes on the low priority queue.  We use
356 	 * this to order frames returned out of the driver
357 	 * ahead of frames we collect in ieee80211_start.
358 	 */
359 	if (m->m_flags & M_ENCAP)
360 		qhead = &psq->psq_head[0];
361 	else
362 		qhead = &psq->psq_head[1];
363 	if (qhead->tail == NULL) {
364 		struct mbuf *mh;
365 
366 		qhead->head = m;
367 		/*
368 		 * Take care to adjust age when inserting the first
369 		 * frame of a queue and the other queue already has
370 		 * frames.  We need to preserve the age difference
371 		 * relationship so ieee80211_node_psq_age works.
372 		 */
373 		if (qhead == &psq->psq_head[1]) {
374 			mh = psq->psq_head[0].head;
375 			if (mh != NULL)
376 				age-= M_AGE_GET(mh);
377 		} else {
378 			mh = psq->psq_head[1].head;
379 			if (mh != NULL) {
380 				int nage = M_AGE_GET(mh) - age;
381 				/* XXX is clamping to zero good 'nuf? */
382 				M_AGE_SET(mh, nage < 0 ? 0 : nage);
383 			}
384 		}
385 	} else {
386 		qhead->tail->m_nextpkt = m;
387 		age -= M_AGE_GET(qhead->head);
388 	}
389 	KASSERT(age >= 0, ("age %d", age));
390 	M_AGE_SET(m, age);
391 	m->m_nextpkt = NULL;
392 	qhead->tail = m;
393 	qhead->len++;
394 	qlen = ++(psq->psq_len);
395 	IEEE80211_PSQ_UNLOCK(psq);
396 
397 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
398 	    "save frame with age %d, %u now queued", age, qlen);
399 
400 	if (qlen == 1 && vap->iv_set_tim != NULL)
401 		vap->iv_set_tim(ni, 1);
402 
403 	return 0;
404 }
405 
406 /*
407  * Move frames from the ps q to the vap's send queue
408  * and/or the driver's send queue; and kick the start
409  * method for each, as appropriate.  Note we're careful
410  * to preserve packet ordering here.
411  */
412 static void
413 pwrsave_flushq(struct ieee80211_node *ni)
414 {
415 	struct ieee80211_psq *psq = &ni->ni_psq;
416 	struct ieee80211com *ic = ni->ni_ic;
417 	struct ieee80211vap *vap = ni->ni_vap;
418 	struct ieee80211_psq_head *qhead;
419 	struct ifnet *parent, *ifp;
420 	struct mbuf *parent_q = NULL, *ifp_q = NULL;
421 	struct mbuf *m;
422 
423 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
424 	    "flush ps queue, %u packets queued", psq->psq_len);
425 
426 	IEEE80211_PSQ_LOCK(psq);
427 	qhead = &psq->psq_head[0];	/* 802.11 frames */
428 	if (qhead->head != NULL) {
429 		/* XXX could dispatch through vap and check M_ENCAP */
430 		parent = vap->iv_ic->ic_ifp;
431 		/* XXX need different driver interface */
432 		/* XXX bypasses q max and OACTIVE */
433 		parent_q = qhead->head;
434 		qhead->head = qhead->tail = NULL;
435 		qhead->len = 0;
436 	} else
437 		parent = NULL;
438 
439 	qhead = &psq->psq_head[1];	/* 802.3 frames */
440 	if (qhead->head != NULL) {
441 		ifp = vap->iv_ifp;
442 		/* XXX need different driver interface */
443 		/* XXX bypasses q max and OACTIVE */
444 		ifp_q = qhead->head;
445 		qhead->head = qhead->tail = NULL;
446 		qhead->len = 0;
447 	} else
448 		ifp = NULL;
449 	psq->psq_len = 0;
450 	IEEE80211_PSQ_UNLOCK(psq);
451 
452 	/* NB: do this outside the psq lock */
453 	/* XXX packets might get reordered if parent is OACTIVE */
454 	/* parent frames, should be encapsulated */
455 	if (parent != NULL) {
456 		while (parent_q != NULL) {
457 			m = parent_q;
458 			parent_q = m->m_nextpkt;
459 			/* must be encapsulated */
460 			KASSERT((m->m_flags & M_ENCAP),
461 			    ("%s: parentq with non-M_ENCAP frame!\n",
462 			    __func__));
463 			/*
464 			 * For encaped frames, we need to free the node
465 			 * reference upon failure.
466 			 */
467 			if (ieee80211_parent_transmit(ic, m) != 0)
468 				ieee80211_free_node(ni);
469 		}
470 	}
471 
472 	/* VAP frames, aren't encapsulated */
473 	if (ifp != NULL) {
474 		while (ifp_q != NULL) {
475 			m = ifp_q;
476 			ifp_q = m->m_nextpkt;
477 			KASSERT((!(m->m_flags & M_ENCAP)),
478 			    ("%s: vapq with M_ENCAP frame!\n", __func__));
479 			(void) ieee80211_vap_transmit(vap, m);
480 		}
481 	}
482 }
483 
484 /*
485  * Handle station power-save state change.
486  */
487 void
488 ieee80211_node_pwrsave(struct ieee80211_node *ni, int enable)
489 {
490 	struct ieee80211vap *vap = ni->ni_vap;
491 	int update;
492 
493 	update = 0;
494 	if (enable) {
495 		if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
496 			vap->iv_ps_sta++;
497 			update = 1;
498 		}
499 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
500 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
501 		    "power save mode on, %u sta's in ps mode", vap->iv_ps_sta);
502 
503 		if (update)
504 			vap->iv_update_ps(vap, vap->iv_ps_sta);
505 	} else {
506 		if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
507 			vap->iv_ps_sta--;
508 			update = 1;
509 		}
510 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
511 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
512 		    "power save mode off, %u sta's in ps mode", vap->iv_ps_sta);
513 
514 		/* NB: order here is intentional so TIM is clear before flush */
515 		if (vap->iv_set_tim != NULL)
516 			vap->iv_set_tim(ni, 0);
517 		if (update) {
518 			/* NB if no sta's in ps, driver should flush mc q */
519 			vap->iv_update_ps(vap, vap->iv_ps_sta);
520 		}
521 		if (ni->ni_psq.psq_len != 0)
522 			pwrsave_flushq(ni);
523 	}
524 }
525 
526 /*
527  * Handle power-save state change in station mode.
528  */
529 void
530 ieee80211_sta_pwrsave(struct ieee80211vap *vap, int enable)
531 {
532 	struct ieee80211_node *ni = vap->iv_bss;
533 
534 	if (!((enable != 0) ^ ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) != 0)))
535 		return;
536 
537 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
538 	    "sta power save mode %s", enable ? "on" : "off");
539 	if (!enable) {
540 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
541 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
542 		/*
543 		 * Flush any queued frames; we can do this immediately
544 		 * because we know they'll be queued behind the null
545 		 * data frame we send the ap.
546 		 * XXX can we use a data frame to take us out of ps?
547 		 */
548 		if (ni->ni_psq.psq_len != 0)
549 			pwrsave_flushq(ni);
550 	} else {
551 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
552 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
553 	}
554 }
555