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  * $FreeBSD: head/sys/net80211/ieee80211_power.c 186302 2008-12-18 23:00:09Z sam $
26  * $DragonFly$
27  */
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 #include <net/route.h>
44 
45 #include <netproto/802_11/ieee80211_var.h>
46 
47 #include <net/bpf.h>
48 
49 static void ieee80211_update_ps(struct ieee80211vap *, int);
50 static int ieee80211_set_tim(struct ieee80211_node *, int);
51 
52 MALLOC_DEFINE(M_80211_POWER, "80211power", "802.11 power save state");
53 
54 void
55 ieee80211_power_attach(struct ieee80211com *ic)
56 {
57 }
58 
59 void
60 ieee80211_power_detach(struct ieee80211com *ic)
61 {
62 }
63 
64 void
65 ieee80211_power_vattach(struct ieee80211vap *vap)
66 {
67 	if (vap->iv_opmode == IEEE80211_M_HOSTAP ||
68 	    vap->iv_opmode == IEEE80211_M_IBSS) {
69 		/* NB: driver should override */
70 		vap->iv_update_ps = ieee80211_update_ps;
71 		vap->iv_set_tim = ieee80211_set_tim;
72 	}
73 }
74 
75 void
76 ieee80211_power_latevattach(struct ieee80211vap *vap)
77 {
78 	/*
79 	 * Allocate these only if needed.  Beware that we
80 	 * know adhoc mode doesn't support ATIM yet...
81 	 */
82 	if (vap->iv_opmode == IEEE80211_M_HOSTAP) {
83 		vap->iv_tim_len = howmany(vap->iv_max_aid,8) * sizeof(uint8_t);
84 		vap->iv_tim_bitmap = (uint8_t *) kmalloc(vap->iv_tim_len,
85 			M_80211_POWER, M_INTWAIT | M_ZERO);
86 		if (vap->iv_tim_bitmap == NULL) {
87 			kprintf("%s: no memory for TIM bitmap!\n", __func__);
88 			/* XXX good enough to keep from crashing? */
89 			vap->iv_tim_len = 0;
90 		}
91 	}
92 }
93 
94 void
95 ieee80211_power_vdetach(struct ieee80211vap *vap)
96 {
97 	if (vap->iv_tim_bitmap != NULL) {
98 		kfree(vap->iv_tim_bitmap, M_80211_POWER);
99 		vap->iv_tim_bitmap = NULL;
100 	}
101 }
102 
103 void
104 ieee80211_psq_init(struct ieee80211_psq *psq, const char *name)
105 {
106 	memset(psq, 0, sizeof(psq));
107 	psq->psq_maxlen = IEEE80211_PS_MAX_QUEUE;
108 	IEEE80211_PSQ_INIT(psq, name);		/* OS-dependent setup */
109 }
110 
111 void
112 ieee80211_psq_cleanup(struct ieee80211_psq *psq)
113 {
114 #if 0
115 	psq_drain(psq);				/* XXX should not be needed? */
116 #else
117 	KASSERT(psq->psq_len == 0, ("%d frames on ps q", psq->psq_len));
118 #endif
119 	IEEE80211_PSQ_DESTROY(psq);		/* OS-dependent cleanup */
120 }
121 
122 /*
123  * Return the highest priority frame in the ps queue.
124  */
125 struct mbuf *
126 ieee80211_node_psq_dequeue(struct ieee80211_node *ni, int *qlen)
127 {
128 	struct ieee80211_psq *psq = &ni->ni_psq;
129 	struct ieee80211_psq_head *qhead;
130 	struct mbuf *m;
131 
132 	IEEE80211_PSQ_LOCK(psq);
133 	qhead = &psq->psq_head[0];
134 again:
135 	if ((m = qhead->head) != NULL) {
136 		if ((qhead->head = m->m_nextpkt) == NULL)
137 			qhead->tail = NULL;
138 		KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
139 		qhead->len--;
140 		KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
141 		psq->psq_len--;
142 		m->m_nextpkt = NULL;
143 	}
144 	if (m == NULL && qhead == &psq->psq_head[0]) {
145 		/* Algol-68 style for loop */
146 		qhead = &psq->psq_head[1];
147 		goto again;
148 	}
149 	if (qlen != NULL)
150 		*qlen = psq->psq_len;
151 	IEEE80211_PSQ_UNLOCK(psq);
152 	return m;
153 }
154 
155 /*
156  * Reclaim an mbuf from the ps q.  If marked with M_ENCAP
157  * we assume there is a node reference that must be relcaimed.
158  */
159 static void
160 psq_mfree(struct mbuf *m)
161 {
162 	if (m->m_flags & M_ENCAP) {
163 		struct ieee80211_node *ni = (void *) m->m_pkthdr.rcvif;
164 		ieee80211_free_node(ni);
165 	}
166 	m->m_nextpkt = NULL;
167 	m_freem(m);
168 }
169 
170 /*
171  * Clear any frames queued in the power save queue.
172  * The number of frames that were present is returned.
173  */
174 static int
175 psq_drain(struct ieee80211_psq *psq)
176 {
177 	struct ieee80211_psq_head *qhead;
178 	struct mbuf *m;
179 	int qlen;
180 
181 	IEEE80211_PSQ_LOCK(psq);
182 	qlen = psq->psq_len;
183 	qhead = &psq->psq_head[0];
184 again:
185 	while ((m = qhead->head) != NULL) {
186 		qhead->head = m->m_nextpkt;
187 		psq_mfree(m);
188 	}
189 	qhead->tail = NULL;
190 	qhead->len = 0;
191 	if (qhead == &psq->psq_head[0]) {	/* Algol-68 style for loop */
192 		qhead = &psq->psq_head[1];
193 		goto again;
194 	}
195 	psq->psq_len = 0;
196 	IEEE80211_PSQ_UNLOCK(psq);
197 
198 	return qlen;
199 }
200 
201 /*
202  * Clear any frames queued in the power save queue.
203  * The number of frames that were present is returned.
204  */
205 int
206 ieee80211_node_psq_drain(struct ieee80211_node *ni)
207 {
208 	return psq_drain(&ni->ni_psq);
209 }
210 
211 /*
212  * Age frames on the power save queue. The aging interval is
213  * 4 times the listen interval specified by the station.  This
214  * number is factored into the age calculations when the frame
215  * is placed on the queue.  We store ages as time differences
216  * so we can check and/or adjust only the head of the list.
217  * If a frame's age exceeds the threshold then discard it.
218  * The number of frames discarded is returned so the caller
219  * can check if it needs to adjust the tim.
220  */
221 int
222 ieee80211_node_psq_age(struct ieee80211_node *ni)
223 {
224 	struct ieee80211_psq *psq = &ni->ni_psq;
225 	int discard = 0;
226 
227 	if (psq->psq_len != 0) {
228 #ifdef IEEE80211_DEBUG
229 		struct ieee80211vap *vap = ni->ni_vap;
230 #endif
231 		struct ieee80211_psq_head *qhead;
232 		struct mbuf *m;
233 
234 		IEEE80211_PSQ_LOCK(psq);
235 		qhead = &psq->psq_head[0];
236 	again:
237 		while ((m = qhead->head) != NULL &&
238 		    M_AGE_GET(m) < IEEE80211_INACT_WAIT) {
239 			IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
240 			     "discard frame, age %u", M_AGE_GET(m));
241 			if ((qhead->head = m->m_nextpkt) == NULL)
242 				qhead->tail = NULL;
243 			KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
244 			qhead->len--;
245 			KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
246 			psq->psq_len--;
247 			psq_mfree(m);
248 			discard++;
249 		}
250 		if (qhead == &psq->psq_head[0]) { /* Algol-68 style for loop */
251 			qhead = &psq->psq_head[1];
252 			goto again;
253 		}
254 		if (m != NULL)
255 			M_AGE_SUB(m, IEEE80211_INACT_WAIT);
256 		IEEE80211_PSQ_UNLOCK(psq);
257 
258 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
259 		    "discard %u frames for age", discard);
260 		IEEE80211_NODE_STAT_ADD(ni, ps_discard, discard);
261 	}
262 	return discard;
263 }
264 
265 /*
266  * Handle a change in the PS station occupancy.
267  */
268 static void
269 ieee80211_update_ps(struct ieee80211vap *vap, int nsta)
270 {
271 
272 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
273 		vap->iv_opmode == IEEE80211_M_IBSS,
274 		("operating mode %u", vap->iv_opmode));
275 }
276 
277 /*
278  * Indicate whether there are frames queued for a station in power-save mode.
279  */
280 static int
281 ieee80211_set_tim(struct ieee80211_node *ni, int set)
282 {
283 	struct ieee80211vap *vap = ni->ni_vap;
284 	struct ieee80211com *ic = ni->ni_ic;
285 	uint16_t aid;
286 	int changed;
287 
288 	ic = ni->ni_ic;
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 ieee80211vap *vap = ni->ni_vap;
417 	struct ieee80211_psq_head *qhead;
418 	struct ifnet *parent, *ifp;
419 
420 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
421 	    "flush ps queue, %u packets queued", psq->psq_len);
422 
423 	IEEE80211_PSQ_LOCK(psq);
424 	qhead = &psq->psq_head[0];	/* 802.11 frames */
425 	if (qhead->head != NULL) {
426 		/* XXX could dispatch through vap and check M_ENCAP */
427 		parent = vap->iv_ic->ic_ifp;
428 		/* XXX need different driver interface */
429 		/* XXX bypasses q max and OACTIVE */
430 		IF_PREPEND_LIST(&parent->if_snd, qhead->head, qhead->tail,
431 		    qhead->len);
432 		qhead->head = qhead->tail = NULL;
433 		qhead->len = 0;
434 	} else
435 		parent = NULL;
436 
437 	qhead = &psq->psq_head[1];	/* 802.3 frames */
438 	if (qhead->head != NULL) {
439 		ifp = vap->iv_ifp;
440 		/* XXX need different driver interface */
441 		/* XXX bypasses q max and OACTIVE */
442 		IF_PREPEND_LIST(&ifp->if_snd, qhead->head, qhead->tail,
443 		    qhead->len);
444 		qhead->head = qhead->tail = NULL;
445 		qhead->len = 0;
446 	} else
447 		ifp = NULL;
448 	psq->psq_len = 0;
449 	IEEE80211_PSQ_UNLOCK(psq);
450 
451 	/* NB: do this outside the psq lock */
452 	/* XXX packets might get reordered if parent is OACTIVE */
453 	if (parent != NULL)
454 		parent->if_start(parent);
455 	if (ifp != NULL)
456 		ifp->if_start(ifp);
457 }
458 
459 /*
460  * Handle station power-save state change.
461  */
462 void
463 ieee80211_node_pwrsave(struct ieee80211_node *ni, int enable)
464 {
465 	struct ieee80211vap *vap = ni->ni_vap;
466 	int update;
467 
468 	update = 0;
469 	if (enable) {
470 		if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
471 			vap->iv_ps_sta++;
472 			update = 1;
473 		}
474 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
475 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
476 		    "power save mode on, %u sta's in ps mode", vap->iv_ps_sta);
477 
478 		if (update)
479 			vap->iv_update_ps(vap, vap->iv_ps_sta);
480 	} else {
481 		if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
482 			vap->iv_ps_sta--;
483 			update = 1;
484 		}
485 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
486 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
487 		    "power save mode off, %u sta's in ps mode", vap->iv_ps_sta);
488 
489 		/* NB: order here is intentional so TIM is clear before flush */
490 		if (vap->iv_set_tim != NULL)
491 			vap->iv_set_tim(ni, 0);
492 		if (update) {
493 			/* NB if no sta's in ps, driver should flush mc q */
494 			vap->iv_update_ps(vap, vap->iv_ps_sta);
495 		}
496 		if (ni->ni_psq.psq_len != 0)
497 			pwrsave_flushq(ni);
498 	}
499 }
500 
501 /*
502  * Handle power-save state change in station mode.
503  */
504 void
505 ieee80211_sta_pwrsave(struct ieee80211vap *vap, int enable)
506 {
507 	struct ieee80211_node *ni = vap->iv_bss;
508 
509 	if (!((enable != 0) ^ ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) != 0)))
510 		return;
511 
512 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
513 	    "sta power save mode %s", enable ? "on" : "off");
514 	if (!enable) {
515 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
516 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
517 		/*
518 		 * Flush any queued frames; we can do this immediately
519 		 * because we know they'll be queued behind the null
520 		 * data frame we send the ap.
521 		 * XXX can we use a data frame to take us out of ps?
522 		 */
523 		if (ni->ni_psq.psq_len != 0)
524 			pwrsave_flushq(ni);
525 	} else {
526 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
527 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
528 	}
529 }
530