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 }
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 	struct ieee80211com *ic = ni->ni_ic;
277 	uint16_t aid;
278 	int changed;
279 
280 	ic = ni->ni_ic;
281 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
282 		vap->iv_opmode == IEEE80211_M_IBSS,
283 		("operating mode %u", vap->iv_opmode));
284 
285 	aid = IEEE80211_AID(ni->ni_associd);
286 	KASSERT(aid < vap->iv_max_aid,
287 		("bogus aid %u, max %u", aid, vap->iv_max_aid));
288 
289 	changed = (set != (isset(vap->iv_tim_bitmap, aid) != 0));
290 	if (changed) {
291 		if (set) {
292 			setbit(vap->iv_tim_bitmap, aid);
293 			vap->iv_ps_pending++;
294 		} else {
295 			clrbit(vap->iv_tim_bitmap, aid);
296 			vap->iv_ps_pending--;
297 		}
298 		/* NB: we know vap is in RUN state so no need to check */
299 		vap->iv_update_beacon(vap, IEEE80211_BEACON_TIM);
300 	}
301 
302 	return changed;
303 }
304 
305 /*
306  * Save an outbound packet for a node in power-save sleep state.
307  * The new packet is placed on the node's saved queue, and the TIM
308  * is changed, if necessary.
309  */
310 int
311 ieee80211_pwrsave(struct ieee80211_node *ni, struct mbuf *m)
312 {
313 	struct ieee80211_psq *psq = &ni->ni_psq;
314 	struct ieee80211vap *vap = ni->ni_vap;
315 	struct ieee80211com *ic = ni->ni_ic;
316 	struct ieee80211_psq_head *qhead;
317 	int qlen, age;
318 
319 	if (psq->psq_len >= psq->psq_maxlen) {
320 		psq->psq_drops++;
321 		IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
322 		    "pwr save q overflow, drops %d (size %d)",
323 		    psq->psq_drops, psq->psq_len);
324 #ifdef IEEE80211_DEBUG
325 		if (ieee80211_msg_dumppkts(vap))
326 			ieee80211_dump_pkt(ni->ni_ic, mtod(m, caddr_t),
327 			    m->m_len, -1, -1);
328 #endif
329 		psq_mfree(m);
330 		return ENOSPC;
331 	}
332 	/*
333 	 * Tag the frame with it's expiry time and insert it in
334 	 * the appropriate queue.  The aging interval is 4 times
335 	 * the listen interval specified by the station. Frames
336 	 * that sit around too long are reclaimed using this
337 	 * information.
338 	 */
339 	/* TU -> secs.  XXX handle overflow? */
340 	age = IEEE80211_TU_TO_MS((ni->ni_intval * ic->ic_bintval) << 2) / 1000;
341 	/*
342 	 * Encapsulated frames go on the high priority queue,
343 	 * other stuff goes on the low priority queue.  We use
344 	 * this to order frames returned out of the driver
345 	 * ahead of frames we collect in ieee80211_start.
346 	 */
347 	if (m->m_flags & M_ENCAP)
348 		qhead = &psq->psq_head[0];
349 	else
350 		qhead = &psq->psq_head[1];
351 	if (qhead->tail == NULL) {
352 		struct mbuf *mh;
353 
354 		qhead->head = m;
355 		/*
356 		 * Take care to adjust age when inserting the first
357 		 * frame of a queue and the other queue already has
358 		 * frames.  We need to preserve the age difference
359 		 * relationship so ieee80211_node_psq_age works.
360 		 */
361 		if (qhead == &psq->psq_head[1]) {
362 			mh = psq->psq_head[0].head;
363 			if (mh != NULL)
364 				age-= M_AGE_GET(mh);
365 		} else {
366 			mh = psq->psq_head[1].head;
367 			if (mh != NULL) {
368 				int nage = M_AGE_GET(mh) - age;
369 				/* XXX is clamping to zero good 'nuf? */
370 				M_AGE_SET(mh, nage < 0 ? 0 : nage);
371 			}
372 		}
373 	} else {
374 		qhead->tail->m_nextpkt = m;
375 		age -= M_AGE_GET(qhead->head);
376 	}
377 	KASSERT(age >= 0, ("age %d", age));
378 	M_AGE_SET(m, age);
379 	m->m_nextpkt = NULL;
380 	qhead->tail = m;
381 	qhead->len++;
382 	qlen = ++(psq->psq_len);
383 
384 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
385 	    "save frame with age %d, %u now queued", age, qlen);
386 
387 	if (qlen == 1 && vap->iv_set_tim != NULL)
388 		vap->iv_set_tim(ni, 1);
389 
390 	return 0;
391 }
392 
393 /*
394  * Move frames from the ps q to the vap's send queue
395  * and/or the driver's send queue; and kick the start
396  * method for each, as appropriate.  Note we're careful
397  * to preserve packet ordering here.
398  */
399 static void
400 pwrsave_flushq(struct ieee80211_node *ni)
401 {
402 	struct ieee80211_psq *psq = &ni->ni_psq;
403 	struct ieee80211vap *vap = ni->ni_vap;
404 	struct ieee80211_psq_head *qhead;
405 	struct ifnet *parent, *ifp;
406 
407 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
408 	    "flush ps queue, %u packets queued", psq->psq_len);
409 
410 	qhead = &psq->psq_head[0];	/* 802.11 frames */
411 	if (qhead->head != NULL) {
412 		/* XXX could dispatch through vap and check M_ENCAP */
413 		parent = vap->iv_ic->ic_ifp;
414 		/* XXX need different driver interface */
415 		/* XXX bypasses q max and OACTIVE */
416 		IF_PREPEND_LIST(&parent->if_snd, qhead->head, qhead->tail,
417 		    qhead->len);
418 		qhead->head = qhead->tail = NULL;
419 		qhead->len = 0;
420 	} else
421 		parent = NULL;
422 
423 	qhead = &psq->psq_head[1];	/* 802.3 frames */
424 	if (qhead->head != NULL) {
425 		ifp = vap->iv_ifp;
426 		/* XXX need different driver interface */
427 		/* XXX bypasses q max and OACTIVE */
428 		IF_PREPEND_LIST(&ifp->if_snd, qhead->head, qhead->tail,
429 		    qhead->len);
430 		qhead->head = qhead->tail = NULL;
431 		qhead->len = 0;
432 	} else
433 		ifp = NULL;
434 	psq->psq_len = 0;
435 
436 	/* NB: do this outside the psq lock */
437 	/* XXX packets might get reordered if parent is OACTIVE */
438 	if (parent != NULL)
439 		parent->if_start(parent);
440 	if (ifp != NULL)
441 		ifp->if_start(ifp);
442 }
443 
444 /*
445  * Handle station power-save state change.
446  */
447 void
448 ieee80211_node_pwrsave(struct ieee80211_node *ni, int enable)
449 {
450 	struct ieee80211vap *vap = ni->ni_vap;
451 	int update;
452 
453 	update = 0;
454 	if (enable) {
455 		if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
456 			vap->iv_ps_sta++;
457 			update = 1;
458 		}
459 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
460 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
461 		    "power save mode on, %u sta's in ps mode", vap->iv_ps_sta);
462 
463 		if (update)
464 			vap->iv_update_ps(vap, vap->iv_ps_sta);
465 	} else {
466 		if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
467 			vap->iv_ps_sta--;
468 			update = 1;
469 		}
470 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
471 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
472 		    "power save mode off, %u sta's in ps mode", vap->iv_ps_sta);
473 
474 		/* NB: order here is intentional so TIM is clear before flush */
475 		if (vap->iv_set_tim != NULL)
476 			vap->iv_set_tim(ni, 0);
477 		if (update) {
478 			/* NB if no sta's in ps, driver should flush mc q */
479 			vap->iv_update_ps(vap, vap->iv_ps_sta);
480 		}
481 		if (ni->ni_psq.psq_len != 0)
482 			pwrsave_flushq(ni);
483 	}
484 }
485 
486 /*
487  * Handle power-save state change in station mode.
488  */
489 void
490 ieee80211_sta_pwrsave(struct ieee80211vap *vap, int enable)
491 {
492 	struct ieee80211_node *ni = vap->iv_bss;
493 
494 	if (!((enable != 0) ^ ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) != 0)))
495 		return;
496 
497 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
498 	    "sta power save mode %s", enable ? "on" : "off");
499 	if (!enable) {
500 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
501 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
502 		/*
503 		 * Flush any queued frames; we can do this immediately
504 		 * because we know they'll be queued behind the null
505 		 * data frame we send the ap.
506 		 * XXX can we use a data frame to take us out of ps?
507 		 */
508 		if (ni->ni_psq.psq_len != 0)
509 			pwrsave_flushq(ni);
510 	} else {
511 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
512 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
513 	}
514 }
515