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  */
27 
28 /*
29  * IEEE 802.11 power save support.
30  */
31 #include "opt_wlan.h"
32 
33 #include <sys/param.h>
34 #include <sys/systm.h>
35 #include <sys/kernel.h>
36 
37 #include <sys/socket.h>
38 
39 #include <net/if.h>
40 #include <net/if_media.h>
41 #include <net/ifq_var.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 }
109 
110 void
111 ieee80211_psq_cleanup(struct ieee80211_psq *psq)
112 {
113 #if 0
114 	psq_drain(psq);				/* XXX should not be needed? */
115 #else
116 	KASSERT(psq->psq_len == 0, ("%d frames on ps q", psq->psq_len));
117 #endif
118 }
119 
120 /*
121  * Return the highest priority frame in the ps queue.
122  */
123 struct mbuf *
124 ieee80211_node_psq_dequeue(struct ieee80211_node *ni, int *qlen)
125 {
126 	struct ieee80211_psq *psq = &ni->ni_psq;
127 	struct ieee80211_psq_head *qhead;
128 	struct mbuf *m;
129 
130 	qhead = &psq->psq_head[0];
131 again:
132 	if ((m = qhead->head) != NULL) {
133 		if ((qhead->head = m->m_nextpkt) == NULL)
134 			qhead->tail = NULL;
135 		KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
136 		qhead->len--;
137 		KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
138 		psq->psq_len--;
139 		m->m_nextpkt = NULL;
140 	}
141 	if (m == NULL && qhead == &psq->psq_head[0]) {
142 		/* Algol-68 style for loop */
143 		qhead = &psq->psq_head[1];
144 		goto again;
145 	}
146 	if (qlen != NULL)
147 		*qlen = psq->psq_len;
148 	return m;
149 }
150 
151 /*
152  * Reclaim an mbuf from the ps q.  If marked with M_ENCAP
153  * we assume there is a node reference that must be relcaimed.
154  */
155 static void
156 psq_mfree(struct mbuf *m)
157 {
158 	if (m->m_flags & M_ENCAP) {
159 		struct ieee80211_node *ni = (void *) m->m_pkthdr.rcvif;
160 		ieee80211_free_node(ni);
161 	}
162 	m->m_nextpkt = NULL;
163 	m_freem(m);
164 }
165 
166 /*
167  * Clear any frames queued in the power save queue.
168  * The number of frames that were present is returned.
169  */
170 static int
171 psq_drain(struct ieee80211_psq *psq)
172 {
173 	struct ieee80211_psq_head *qhead;
174 	struct mbuf *m;
175 	int qlen;
176 
177 	qlen = psq->psq_len;
178 	qhead = &psq->psq_head[0];
179 again:
180 	while ((m = qhead->head) != NULL) {
181 		qhead->head = m->m_nextpkt;
182 		psq_mfree(m);
183 	}
184 	qhead->tail = NULL;
185 	qhead->len = 0;
186 	if (qhead == &psq->psq_head[0]) {	/* Algol-68 style for loop */
187 		qhead = &psq->psq_head[1];
188 		goto again;
189 	}
190 	psq->psq_len = 0;
191 
192 	return qlen;
193 }
194 
195 /*
196  * Clear any frames queued in the power save queue.
197  * The number of frames that were present is returned.
198  */
199 int
200 ieee80211_node_psq_drain(struct ieee80211_node *ni)
201 {
202 	return psq_drain(&ni->ni_psq);
203 }
204 
205 /*
206  * Age frames on the power save queue. The aging interval is
207  * 4 times the listen interval specified by the station.  This
208  * number is factored into the age calculations when the frame
209  * is placed on the queue.  We store ages as time differences
210  * so we can check and/or adjust only the head of the list.
211  * If a frame's age exceeds the threshold then discard it.
212  * The number of frames discarded is returned so the caller
213  * can check if it needs to adjust the tim.
214  */
215 int
216 ieee80211_node_psq_age(struct ieee80211_node *ni)
217 {
218 	struct ieee80211_psq *psq = &ni->ni_psq;
219 	int discard = 0;
220 
221 	if (psq->psq_len != 0) {
222 #ifdef IEEE80211_DEBUG
223 		struct ieee80211vap *vap = ni->ni_vap;
224 #endif
225 		struct ieee80211_psq_head *qhead;
226 		struct mbuf *m;
227 
228 		qhead = &psq->psq_head[0];
229 	again:
230 		while ((m = qhead->head) != NULL &&
231 		    M_AGE_GET(m) < IEEE80211_INACT_WAIT) {
232 			IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
233 			     "discard frame, age %u", M_AGE_GET(m));
234 			if ((qhead->head = m->m_nextpkt) == NULL)
235 				qhead->tail = NULL;
236 			KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
237 			qhead->len--;
238 			KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
239 			psq->psq_len--;
240 			psq_mfree(m);
241 			discard++;
242 		}
243 		if (qhead == &psq->psq_head[0]) { /* Algol-68 style for loop */
244 			qhead = &psq->psq_head[1];
245 			goto again;
246 		}
247 		if (m != NULL)
248 			M_AGE_SUB(m, IEEE80211_INACT_WAIT);
249 
250 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
251 		    "discard %u frames for age", discard);
252 		IEEE80211_NODE_STAT_ADD(ni, ps_discard, discard);
253 	}
254 	return discard;
255 }
256 
257 /*
258  * Handle a change in the PS station occupancy.
259  */
260 static void
261 ieee80211_update_ps(struct ieee80211vap *vap, int nsta)
262 {
263 
264 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
265 		vap->iv_opmode == IEEE80211_M_IBSS,
266 		("operating mode %u", vap->iv_opmode));
267 }
268 
269 /*
270  * Indicate whether there are frames queued for a station in power-save mode.
271  */
272 static int
273 ieee80211_set_tim(struct ieee80211_node *ni, int set)
274 {
275 	struct ieee80211vap *vap = ni->ni_vap;
276 	uint16_t aid;
277 	int changed;
278 
279 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
280 		vap->iv_opmode == IEEE80211_M_IBSS,
281 		("operating mode %u", vap->iv_opmode));
282 
283 	aid = IEEE80211_AID(ni->ni_associd);
284 	KASSERT(aid < vap->iv_max_aid,
285 		("bogus aid %u, max %u", aid, vap->iv_max_aid));
286 
287 	changed = (set != (isset(vap->iv_tim_bitmap, aid) != 0));
288 	if (changed) {
289 		if (set) {
290 			setbit(vap->iv_tim_bitmap, aid);
291 			vap->iv_ps_pending++;
292 		} else {
293 			clrbit(vap->iv_tim_bitmap, aid);
294 			vap->iv_ps_pending--;
295 		}
296 		/* NB: we know vap is in RUN state so no need to check */
297 		vap->iv_update_beacon(vap, IEEE80211_BEACON_TIM);
298 	}
299 
300 	return changed;
301 }
302 
303 /*
304  * Save an outbound packet for a node in power-save sleep state.
305  * The new packet is placed on the node's saved queue, and the TIM
306  * is changed, if necessary.
307  */
308 int
309 ieee80211_pwrsave(struct ieee80211_node *ni, struct mbuf *m)
310 {
311 	struct ieee80211_psq *psq = &ni->ni_psq;
312 	struct ieee80211vap *vap = ni->ni_vap;
313 	struct ieee80211com *ic = ni->ni_ic;
314 	struct ieee80211_psq_head *qhead;
315 	int qlen, age;
316 
317 	if (psq->psq_len >= psq->psq_maxlen) {
318 		psq->psq_drops++;
319 		IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
320 		    "pwr save q overflow, drops %d (size %d)",
321 		    psq->psq_drops, psq->psq_len);
322 #ifdef IEEE80211_DEBUG
323 		if (ieee80211_msg_dumppkts(vap))
324 			ieee80211_dump_pkt(ni->ni_ic, mtod(m, caddr_t),
325 			    m->m_len, -1, -1);
326 #endif
327 		psq_mfree(m);
328 		return ENOSPC;
329 	}
330 	/*
331 	 * Tag the frame with it's expiry time and insert it in
332 	 * the appropriate queue.  The aging interval is 4 times
333 	 * the listen interval specified by the station. Frames
334 	 * that sit around too long are reclaimed using this
335 	 * information.
336 	 */
337 	/* TU -> secs.  XXX handle overflow? */
338 	age = IEEE80211_TU_TO_MS((ni->ni_intval * ic->ic_bintval) << 2) / 1000;
339 	/*
340 	 * Encapsulated frames go on the high priority queue,
341 	 * other stuff goes on the low priority queue.  We use
342 	 * this to order frames returned out of the driver
343 	 * ahead of frames we collect in ieee80211_start.
344 	 */
345 	if (m->m_flags & M_ENCAP)
346 		qhead = &psq->psq_head[0];
347 	else
348 		qhead = &psq->psq_head[1];
349 	if (qhead->tail == NULL) {
350 		struct mbuf *mh;
351 
352 		qhead->head = m;
353 		/*
354 		 * Take care to adjust age when inserting the first
355 		 * frame of a queue and the other queue already has
356 		 * frames.  We need to preserve the age difference
357 		 * relationship so ieee80211_node_psq_age works.
358 		 */
359 		if (qhead == &psq->psq_head[1]) {
360 			mh = psq->psq_head[0].head;
361 			if (mh != NULL)
362 				age-= M_AGE_GET(mh);
363 		} else {
364 			mh = psq->psq_head[1].head;
365 			if (mh != NULL) {
366 				int nage = M_AGE_GET(mh) - age;
367 				/* XXX is clamping to zero good 'nuf? */
368 				M_AGE_SET(mh, nage < 0 ? 0 : nage);
369 			}
370 		}
371 	} else {
372 		qhead->tail->m_nextpkt = m;
373 		age -= M_AGE_GET(qhead->head);
374 	}
375 	KASSERT(age >= 0, ("age %d", age));
376 	M_AGE_SET(m, age);
377 	m->m_nextpkt = NULL;
378 	qhead->tail = m;
379 	qhead->len++;
380 	qlen = ++(psq->psq_len);
381 
382 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
383 	    "save frame with age %d, %u now queued", age, qlen);
384 
385 	if (qlen == 1 && vap->iv_set_tim != NULL)
386 		vap->iv_set_tim(ni, 1);
387 
388 	return 0;
389 }
390 
391 /*
392  * Move frames from the ps q to the vap's send queue
393  * and/or the driver's send queue; and kick the start
394  * method for each, as appropriate.  Note we're careful
395  * to preserve packet ordering here.
396  */
397 static void
398 pwrsave_flushq(struct ieee80211_node *ni)
399 {
400 	struct ieee80211_psq *psq = &ni->ni_psq;
401 	struct ieee80211vap *vap = ni->ni_vap;
402 	struct ieee80211_psq_head *qhead;
403 	struct ifnet *parent, *ifp;
404 	struct ifaltq_subque *ifp_ifsq, *parent_ifsq;
405 
406 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
407 	    "flush ps queue, %u packets queued", psq->psq_len);
408 
409 	qhead = &psq->psq_head[0];	/* 802.11 frames */
410 	if (qhead->head != NULL) {
411 		/* XXX could dispatch through vap and check M_ENCAP */
412 		parent = vap->iv_ic->ic_ifp;
413 		parent_ifsq = ifq_get_subq_default(&parent->if_snd);
414 
415 		/* XXX this breaks ALTQ's packet scheduler */
416 		ALTQ_SQ_LOCK(parent_ifsq);
417 		/* XXX need different driver interface */
418 		/* XXX bypasses q max and OACTIVE */
419 		IF_PREPEND_LIST(parent_ifsq, qhead->head, qhead->tail,
420 		    qhead->len);
421 		ALTQ_SQ_UNLOCK(parent_ifsq);
422 
423 		qhead->head = qhead->tail = NULL;
424 		qhead->len = 0;
425 	} else {
426 		parent = NULL;
427 		parent_ifsq = NULL;
428 	}
429 
430 	qhead = &psq->psq_head[1];	/* 802.3 frames */
431 	if (qhead->head != NULL) {
432 		ifp = vap->iv_ifp;
433 		ifp_ifsq = ifq_get_subq_default(&ifp->if_snd);
434 
435 		/* XXX this breaks ALTQ's packet scheduler */
436 		ALTQ_SQ_LOCK(ifp_ifsq);
437 		/* XXX need different driver interface */
438 		/* XXX bypasses q max and OACTIVE */
439 		IF_PREPEND_LIST(ifp_ifsq, qhead->head, qhead->tail, qhead->len);
440 		ALTQ_SQ_UNLOCK(ifp_ifsq);
441 
442 		qhead->head = qhead->tail = NULL;
443 		qhead->len = 0;
444 	} else {
445 		ifp = NULL;
446 		ifp_ifsq = NULL;
447 	}
448 	psq->psq_len = 0;
449 
450 	/* NB: do this outside the psq lock */
451 	/* XXX packets might get reordered if parent is OACTIVE */
452 	if (parent != NULL && parent_ifsq != NULL)
453 		parent->if_start(parent, parent_ifsq);
454 	if (ifp != NULL && ifp_ifsq != NULL)
455 		ifp->if_start(ifp, ifp_ifsq);
456 }
457 
458 /*
459  * Handle station power-save state change.
460  */
461 void
462 ieee80211_node_pwrsave(struct ieee80211_node *ni, int enable)
463 {
464 	struct ieee80211vap *vap = ni->ni_vap;
465 	int update;
466 
467 	update = 0;
468 	if (enable) {
469 		if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
470 			vap->iv_ps_sta++;
471 			update = 1;
472 		}
473 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
474 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
475 		    "power save mode on, %u sta's in ps mode", vap->iv_ps_sta);
476 
477 		if (update)
478 			vap->iv_update_ps(vap, vap->iv_ps_sta);
479 	} else {
480 		if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
481 			vap->iv_ps_sta--;
482 			update = 1;
483 		}
484 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
485 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
486 		    "power save mode off, %u sta's in ps mode", vap->iv_ps_sta);
487 
488 		/* NB: order here is intentional so TIM is clear before flush */
489 		if (vap->iv_set_tim != NULL)
490 			vap->iv_set_tim(ni, 0);
491 		if (update) {
492 			/* NB if no sta's in ps, driver should flush mc q */
493 			vap->iv_update_ps(vap, vap->iv_ps_sta);
494 		}
495 		if (ni->ni_psq.psq_len != 0)
496 			pwrsave_flushq(ni);
497 	}
498 }
499 
500 /*
501  * Handle power-save state change in station mode.
502  */
503 void
504 ieee80211_sta_pwrsave(struct ieee80211vap *vap, int enable)
505 {
506 	struct ieee80211_node *ni = vap->iv_bss;
507 
508 	if (!((enable != 0) ^ ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) != 0)))
509 		return;
510 
511 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
512 	    "sta power save mode %s", enable ? "on" : "off");
513 	if (!enable) {
514 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
515 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
516 		/*
517 		 * Flush any queued frames; we can do this immediately
518 		 * because we know they'll be queued behind the null
519 		 * data frame we send the ap.
520 		 * XXX can we use a data frame to take us out of ps?
521 		 */
522 		if (ni->ni_psq.psq_len != 0)
523 			pwrsave_flushq(ni);
524 	} else {
525 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
526 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
527 	}
528 }
529