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/ethernet.h>
42 #include <net/route.h>
43 
44 #include <netproto/802_11/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 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 }
73 
74 void
75 ieee80211_power_latevattach(struct ieee80211vap *vap)
76 {
77 	/*
78 	 * Allocate these only if needed.  Beware that we
79 	 * know adhoc mode doesn't support ATIM yet...
80 	 */
81 	if (vap->iv_opmode == IEEE80211_M_HOSTAP) {
82 		vap->iv_tim_len = howmany(vap->iv_max_aid,8) * sizeof(uint8_t);
83 		vap->iv_tim_bitmap = (uint8_t *) kmalloc(vap->iv_tim_len,
84 			M_80211_POWER, M_INTWAIT | M_ZERO);
85 		if (vap->iv_tim_bitmap == NULL) {
86 			kprintf("%s: no memory for TIM bitmap!\n", __func__);
87 			/* XXX good enough to keep from crashing? */
88 			vap->iv_tim_len = 0;
89 		}
90 	}
91 }
92 
93 void
94 ieee80211_power_vdetach(struct ieee80211vap *vap)
95 {
96 	if (vap->iv_tim_bitmap != NULL) {
97 		kfree(vap->iv_tim_bitmap, M_80211_POWER);
98 		vap->iv_tim_bitmap = NULL;
99 	}
100 }
101 
102 void
103 ieee80211_psq_init(struct ieee80211_psq *psq, const char *name)
104 {
105 	memset(psq, 0, sizeof(*psq));
106 	psq->psq_maxlen = IEEE80211_PS_MAX_QUEUE;
107 }
108 
109 void
110 ieee80211_psq_cleanup(struct ieee80211_psq *psq)
111 {
112 #if 0
113 	psq_drain(psq);				/* XXX should not be needed? */
114 #else
115 	KASSERT(psq->psq_len == 0, ("%d frames on ps q", psq->psq_len));
116 #endif
117 }
118 
119 /*
120  * Return the highest priority frame in the ps queue.
121  */
122 struct mbuf *
123 ieee80211_node_psq_dequeue(struct ieee80211_node *ni, int *qlen)
124 {
125 	struct ieee80211_psq *psq = &ni->ni_psq;
126 	struct ieee80211_psq_head *qhead;
127 	struct mbuf *m;
128 
129 	qhead = &psq->psq_head[0];
130 again:
131 	if ((m = qhead->head) != NULL) {
132 		if ((qhead->head = m->m_nextpkt) == NULL)
133 			qhead->tail = NULL;
134 		KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
135 		qhead->len--;
136 		KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
137 		psq->psq_len--;
138 		m->m_nextpkt = NULL;
139 	}
140 	if (m == NULL && qhead == &psq->psq_head[0]) {
141 		/* Algol-68 style for loop */
142 		qhead = &psq->psq_head[1];
143 		goto again;
144 	}
145 	if (qlen != NULL)
146 		*qlen = psq->psq_len;
147 	return m;
148 }
149 
150 /*
151  * Reclaim an mbuf from the ps q.  If marked with M_ENCAP
152  * we assume there is a node reference that must be relcaimed.
153  */
154 static void
155 psq_mfree(struct mbuf *m)
156 {
157 	if (m->m_flags & M_ENCAP) {
158 		struct ieee80211_node *ni = (void *) m->m_pkthdr.rcvif;
159 		ieee80211_free_node(ni);
160 	}
161 	m->m_nextpkt = NULL;
162 	m_freem(m);
163 }
164 
165 /*
166  * Clear any frames queued in the power save queue.
167  * The number of frames that were present is returned.
168  */
169 static int
170 psq_drain(struct ieee80211_psq *psq)
171 {
172 	struct ieee80211_psq_head *qhead;
173 	struct mbuf *m;
174 	int qlen;
175 
176 	qlen = psq->psq_len;
177 	qhead = &psq->psq_head[0];
178 again:
179 	while ((m = qhead->head) != NULL) {
180 		qhead->head = m->m_nextpkt;
181 		psq_mfree(m);
182 	}
183 	qhead->tail = NULL;
184 	qhead->len = 0;
185 	if (qhead == &psq->psq_head[0]) {	/* Algol-68 style for loop */
186 		qhead = &psq->psq_head[1];
187 		goto again;
188 	}
189 	psq->psq_len = 0;
190 
191 	return qlen;
192 }
193 
194 /*
195  * Clear any frames queued in the power save queue.
196  * The number of frames that were present is returned.
197  */
198 int
199 ieee80211_node_psq_drain(struct ieee80211_node *ni)
200 {
201 	return psq_drain(&ni->ni_psq);
202 }
203 
204 /*
205  * Age frames on the power save queue. The aging interval is
206  * 4 times the listen interval specified by the station.  This
207  * number is factored into the age calculations when the frame
208  * is placed on the queue.  We store ages as time differences
209  * so we can check and/or adjust only the head of the list.
210  * If a frame's age exceeds the threshold then discard it.
211  * The number of frames discarded is returned so the caller
212  * can check if it needs to adjust the tim.
213  */
214 int
215 ieee80211_node_psq_age(struct ieee80211_node *ni)
216 {
217 	struct ieee80211_psq *psq = &ni->ni_psq;
218 	int discard = 0;
219 
220 	if (psq->psq_len != 0) {
221 #ifdef IEEE80211_DEBUG
222 		struct ieee80211vap *vap = ni->ni_vap;
223 #endif
224 		struct ieee80211_psq_head *qhead;
225 		struct mbuf *m;
226 
227 		qhead = &psq->psq_head[0];
228 	again:
229 		while ((m = qhead->head) != NULL &&
230 		    M_AGE_GET(m) < IEEE80211_INACT_WAIT) {
231 			IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
232 			     "discard frame, age %u", M_AGE_GET(m));
233 			if ((qhead->head = m->m_nextpkt) == NULL)
234 				qhead->tail = NULL;
235 			KASSERT(qhead->len > 0, ("qhead len %d", qhead->len));
236 			qhead->len--;
237 			KASSERT(psq->psq_len > 0, ("psq len %d", psq->psq_len));
238 			psq->psq_len--;
239 			psq_mfree(m);
240 			discard++;
241 		}
242 		if (qhead == &psq->psq_head[0]) { /* Algol-68 style for loop */
243 			qhead = &psq->psq_head[1];
244 			goto again;
245 		}
246 		if (m != NULL)
247 			M_AGE_SUB(m, IEEE80211_INACT_WAIT);
248 
249 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
250 		    "discard %u frames for age", discard);
251 		IEEE80211_NODE_STAT_ADD(ni, ps_discard, discard);
252 	}
253 	return discard;
254 }
255 
256 /*
257  * Handle a change in the PS station occupancy.
258  */
259 static void
260 ieee80211_update_ps(struct ieee80211vap *vap, int nsta)
261 {
262 
263 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
264 		vap->iv_opmode == IEEE80211_M_IBSS,
265 		("operating mode %u", vap->iv_opmode));
266 }
267 
268 /*
269  * Indicate whether there are frames queued for a station in power-save mode.
270  */
271 static int
272 ieee80211_set_tim(struct ieee80211_node *ni, int set)
273 {
274 	struct ieee80211vap *vap = ni->ni_vap;
275 	struct ieee80211com *ic = ni->ni_ic;
276 	uint16_t aid;
277 	int changed;
278 
279 	ic = ni->ni_ic;
280 	KASSERT(vap->iv_opmode == IEEE80211_M_HOSTAP ||
281 		vap->iv_opmode == IEEE80211_M_IBSS,
282 		("operating mode %u", vap->iv_opmode));
283 
284 	aid = IEEE80211_AID(ni->ni_associd);
285 	KASSERT(aid < vap->iv_max_aid,
286 		("bogus aid %u, max %u", aid, vap->iv_max_aid));
287 
288 	changed = (set != (isset(vap->iv_tim_bitmap, aid) != 0));
289 	if (changed) {
290 		if (set) {
291 			setbit(vap->iv_tim_bitmap, aid);
292 			vap->iv_ps_pending++;
293 		} else {
294 			clrbit(vap->iv_tim_bitmap, aid);
295 			vap->iv_ps_pending--;
296 		}
297 		/* NB: we know vap is in RUN state so no need to check */
298 		vap->iv_update_beacon(vap, IEEE80211_BEACON_TIM);
299 	}
300 
301 	return changed;
302 }
303 
304 /*
305  * Save an outbound packet for a node in power-save sleep state.
306  * The new packet is placed on the node's saved queue, and the TIM
307  * is changed, if necessary.
308  */
309 int
310 ieee80211_pwrsave(struct ieee80211_node *ni, struct mbuf *m)
311 {
312 	struct ieee80211_psq *psq = &ni->ni_psq;
313 	struct ieee80211vap *vap = ni->ni_vap;
314 	struct ieee80211com *ic = ni->ni_ic;
315 	struct ieee80211_psq_head *qhead;
316 	int qlen, age;
317 
318 	if (psq->psq_len >= psq->psq_maxlen) {
319 		psq->psq_drops++;
320 		IEEE80211_NOTE(vap, IEEE80211_MSG_ANY, ni,
321 		    "pwr save q overflow, drops %d (size %d)",
322 		    psq->psq_drops, psq->psq_len);
323 #ifdef IEEE80211_DEBUG
324 		if (ieee80211_msg_dumppkts(vap))
325 			ieee80211_dump_pkt(ni->ni_ic, mtod(m, caddr_t),
326 			    m->m_len, -1, -1);
327 #endif
328 		psq_mfree(m);
329 		return ENOSPC;
330 	}
331 	/*
332 	 * Tag the frame with it's expiry time and insert it in
333 	 * the appropriate queue.  The aging interval is 4 times
334 	 * the listen interval specified by the station. Frames
335 	 * that sit around too long are reclaimed using this
336 	 * information.
337 	 */
338 	/* TU -> secs.  XXX handle overflow? */
339 	age = IEEE80211_TU_TO_MS((ni->ni_intval * ic->ic_bintval) << 2) / 1000;
340 	/*
341 	 * Encapsulated frames go on the high priority queue,
342 	 * other stuff goes on the low priority queue.  We use
343 	 * this to order frames returned out of the driver
344 	 * ahead of frames we collect in ieee80211_start.
345 	 */
346 	if (m->m_flags & M_ENCAP)
347 		qhead = &psq->psq_head[0];
348 	else
349 		qhead = &psq->psq_head[1];
350 	if (qhead->tail == NULL) {
351 		struct mbuf *mh;
352 
353 		qhead->head = m;
354 		/*
355 		 * Take care to adjust age when inserting the first
356 		 * frame of a queue and the other queue already has
357 		 * frames.  We need to preserve the age difference
358 		 * relationship so ieee80211_node_psq_age works.
359 		 */
360 		if (qhead == &psq->psq_head[1]) {
361 			mh = psq->psq_head[0].head;
362 			if (mh != NULL)
363 				age-= M_AGE_GET(mh);
364 		} else {
365 			mh = psq->psq_head[1].head;
366 			if (mh != NULL) {
367 				int nage = M_AGE_GET(mh) - age;
368 				/* XXX is clamping to zero good 'nuf? */
369 				M_AGE_SET(mh, nage < 0 ? 0 : nage);
370 			}
371 		}
372 	} else {
373 		qhead->tail->m_nextpkt = m;
374 		age -= M_AGE_GET(qhead->head);
375 	}
376 	KASSERT(age >= 0, ("age %d", age));
377 	M_AGE_SET(m, age);
378 	m->m_nextpkt = NULL;
379 	qhead->tail = m;
380 	qhead->len++;
381 	qlen = ++(psq->psq_len);
382 
383 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
384 	    "save frame with age %d, %u now queued", age, qlen);
385 
386 	if (qlen == 1 && vap->iv_set_tim != NULL)
387 		vap->iv_set_tim(ni, 1);
388 
389 	return 0;
390 }
391 
392 /*
393  * Move frames from the ps q to the vap's send queue
394  * and/or the driver's send queue; and kick the start
395  * method for each, as appropriate.  Note we're careful
396  * to preserve packet ordering here.
397  */
398 static void
399 pwrsave_flushq(struct ieee80211_node *ni)
400 {
401 	struct ieee80211_psq *psq = &ni->ni_psq;
402 	struct ieee80211vap *vap = ni->ni_vap;
403 	struct ieee80211_psq_head *qhead;
404 	struct ifnet *parent, *ifp;
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 		/* XXX need different driver interface */
414 		/* XXX bypasses q max and OACTIVE */
415 		IF_PREPEND_LIST(&parent->if_snd, qhead->head, qhead->tail,
416 		    qhead->len);
417 		qhead->head = qhead->tail = NULL;
418 		qhead->len = 0;
419 	} else
420 		parent = NULL;
421 
422 	qhead = &psq->psq_head[1];	/* 802.3 frames */
423 	if (qhead->head != NULL) {
424 		ifp = vap->iv_ifp;
425 		/* XXX need different driver interface */
426 		/* XXX bypasses q max and OACTIVE */
427 		IF_PREPEND_LIST(&ifp->if_snd, qhead->head, qhead->tail,
428 		    qhead->len);
429 		qhead->head = qhead->tail = NULL;
430 		qhead->len = 0;
431 	} else
432 		ifp = NULL;
433 	psq->psq_len = 0;
434 
435 	/* NB: do this outside the psq lock */
436 	/* XXX packets might get reordered if parent is OACTIVE */
437 	if (parent != NULL)
438 		parent->if_start(parent);
439 	if (ifp != NULL)
440 		ifp->if_start(ifp);
441 }
442 
443 /*
444  * Handle station power-save state change.
445  */
446 void
447 ieee80211_node_pwrsave(struct ieee80211_node *ni, int enable)
448 {
449 	struct ieee80211vap *vap = ni->ni_vap;
450 	int update;
451 
452 	update = 0;
453 	if (enable) {
454 		if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) == 0) {
455 			vap->iv_ps_sta++;
456 			update = 1;
457 		}
458 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
459 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
460 		    "power save mode on, %u sta's in ps mode", vap->iv_ps_sta);
461 
462 		if (update)
463 			vap->iv_update_ps(vap, vap->iv_ps_sta);
464 	} else {
465 		if (ni->ni_flags & IEEE80211_NODE_PWR_MGT) {
466 			vap->iv_ps_sta--;
467 			update = 1;
468 		}
469 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
470 		IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
471 		    "power save mode off, %u sta's in ps mode", vap->iv_ps_sta);
472 
473 		/* NB: order here is intentional so TIM is clear before flush */
474 		if (vap->iv_set_tim != NULL)
475 			vap->iv_set_tim(ni, 0);
476 		if (update) {
477 			/* NB if no sta's in ps, driver should flush mc q */
478 			vap->iv_update_ps(vap, vap->iv_ps_sta);
479 		}
480 		if (ni->ni_psq.psq_len != 0)
481 			pwrsave_flushq(ni);
482 	}
483 }
484 
485 /*
486  * Handle power-save state change in station mode.
487  */
488 void
489 ieee80211_sta_pwrsave(struct ieee80211vap *vap, int enable)
490 {
491 	struct ieee80211_node *ni = vap->iv_bss;
492 
493 	if (!((enable != 0) ^ ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) != 0)))
494 		return;
495 
496 	IEEE80211_NOTE(vap, IEEE80211_MSG_POWER, ni,
497 	    "sta power save mode %s", enable ? "on" : "off");
498 	if (!enable) {
499 		ni->ni_flags &= ~IEEE80211_NODE_PWR_MGT;
500 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
501 		/*
502 		 * Flush any queued frames; we can do this immediately
503 		 * because we know they'll be queued behind the null
504 		 * data frame we send the ap.
505 		 * XXX can we use a data frame to take us out of ps?
506 		 */
507 		if (ni->ni_psq.psq_len != 0)
508 			pwrsave_flushq(ni);
509 	} else {
510 		ni->ni_flags |= IEEE80211_NODE_PWR_MGT;
511 		ieee80211_send_nulldata(ieee80211_ref_node(ni));
512 	}
513 }
514