1 /*
2  * Copyright (c) 2001 Atsushi Onoe
3  * Copyright (c) 2002-2005 Sam Leffler, Errno Consulting
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  * 3. The name of the author may not be used to endorse or promote products
15  *    derived from this software without specific prior written permission.
16  *
17  * Alternatively, this software may be distributed under the terms of the
18  * GNU General Public License ("GPL") version 2 as published by the Free
19  * Software Foundation.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
22  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
23  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
27  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
28  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31  *
32  * $FreeBSD: src/sys/net80211/ieee80211_output.c,v 1.26.2.8 2006/09/02 15:06:04 sam Exp $
33  * $DragonFly: src/sys/netproto/802_11/wlan/ieee80211_output.c,v 1.13 2007/01/01 08:51:45 sephe Exp $
34  */
35 
36 #include "opt_inet.h"
37 
38 #include <sys/param.h>
39 #include <sys/systm.h>
40 #include <sys/mbuf.h>
41 #include <sys/kernel.h>
42 #include <sys/endian.h>
43 
44 #include <sys/socket.h>
45 
46 #include <net/bpf.h>
47 #include <net/ethernet.h>
48 #include <net/if.h>
49 #include <net/if_arp.h>
50 #include <net/if_llc.h>
51 #include <net/if_media.h>
52 #include <net/vlan/if_vlan_var.h>
53 
54 #include <netproto/802_11/ieee80211_var.h>
55 
56 #ifdef INET
57 #include <netinet/in.h>
58 #include <netinet/if_ether.h>
59 #include <netinet/in_systm.h>
60 #include <netinet/ip.h>
61 #endif
62 
63 #ifdef IEEE80211_DEBUG
64 /*
65  * Decide if an outbound management frame should be
66  * printed when debugging is enabled.  This filters some
67  * of the less interesting frames that come frequently
68  * (e.g. beacons).
69  */
70 static __inline int
71 doprint(struct ieee80211com *ic, int subtype)
72 {
73 	switch (subtype) {
74 	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
75 		return (ic->ic_opmode == IEEE80211_M_IBSS);
76 	}
77 	return 1;
78 }
79 #endif
80 
81 /*
82  * Set the direction field and address fields of an outgoing
83  * non-QoS frame.  Note this should be called early on in
84  * constructing a frame as it sets i_fc[1]; other bits can
85  * then be or'd in.
86  */
87 static void
88 ieee80211_send_setup(struct ieee80211com *ic,
89 	struct ieee80211_node *ni,
90 	struct ieee80211_frame *wh,
91 	int type,
92 	const uint8_t sa[IEEE80211_ADDR_LEN],
93 	const uint8_t da[IEEE80211_ADDR_LEN],
94 	const uint8_t bssid[IEEE80211_ADDR_LEN])
95 {
96 #define	WH4(wh)	((struct ieee80211_frame_addr4 *)wh)
97 
98 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | type;
99 	if ((type & IEEE80211_FC0_TYPE_MASK) == IEEE80211_FC0_TYPE_DATA) {
100 		switch (ic->ic_opmode) {
101 		case IEEE80211_M_STA:
102 			wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
103 			IEEE80211_ADDR_COPY(wh->i_addr1, bssid);
104 			IEEE80211_ADDR_COPY(wh->i_addr2, sa);
105 			IEEE80211_ADDR_COPY(wh->i_addr3, da);
106 			break;
107 		case IEEE80211_M_IBSS:
108 		case IEEE80211_M_AHDEMO:
109 			wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
110 			IEEE80211_ADDR_COPY(wh->i_addr1, da);
111 			IEEE80211_ADDR_COPY(wh->i_addr2, sa);
112 			IEEE80211_ADDR_COPY(wh->i_addr3, bssid);
113 			break;
114 		case IEEE80211_M_HOSTAP:
115 			wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
116 			IEEE80211_ADDR_COPY(wh->i_addr1, da);
117 			IEEE80211_ADDR_COPY(wh->i_addr2, bssid);
118 			IEEE80211_ADDR_COPY(wh->i_addr3, sa);
119 			break;
120 		case IEEE80211_M_MONITOR:	/* NB: to quiet compiler */
121 			break;
122 		}
123 	} else {
124 		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
125 		IEEE80211_ADDR_COPY(wh->i_addr1, da);
126 		IEEE80211_ADDR_COPY(wh->i_addr2, sa);
127 		IEEE80211_ADDR_COPY(wh->i_addr3, bssid);
128 	}
129 	*(uint16_t *)&wh->i_dur[0] = 0;
130 	/* NB: use non-QoS tid */
131 	*(uint16_t *)&wh->i_seq[0] =
132 	    htole16(ni->ni_txseqs[0] << IEEE80211_SEQ_SEQ_SHIFT);
133 	ni->ni_txseqs[0]++;
134 #undef WH4
135 }
136 
137 /*
138  * Send a management frame to the specified node.  The node pointer
139  * must have a reference as the pointer will be passed to the driver
140  * and potentially held for a long time.  If the frame is successfully
141  * dispatched to the driver, then it is responsible for freeing the
142  * reference (and potentially free'ing up any associated storage).
143  */
144 static int
145 ieee80211_mgmt_output(struct ieee80211com *ic, struct ieee80211_node *ni,
146     struct mbuf *m, int type, int timer)
147 {
148 	struct ifnet *ifp = ic->ic_ifp;
149 	struct ieee80211_frame *wh;
150 
151 	KASSERT(ni != NULL, ("null node"));
152 
153 	/*
154 	 * Yech, hack alert!  We want to pass the node down to the
155 	 * driver's start routine.  If we don't do so then the start
156 	 * routine must immediately look it up again and that can
157 	 * cause a lock order reversal if, for example, this frame
158 	 * is being sent because the station is being timedout and
159 	 * the frame being sent is a DEAUTH message.  We could stick
160 	 * this in an m_tag and tack that on to the mbuf.  However
161 	 * that's rather expensive to do for every frame so instead
162 	 * we stuff it in the rcvif field since outbound frames do
163 	 * not (presently) use this.
164 	 */
165 	M_PREPEND(m, sizeof(struct ieee80211_frame), MB_DONTWAIT);
166 	if (m == NULL)
167 		return ENOMEM;
168 	KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
169 	m->m_pkthdr.rcvif = (void *)ni;
170 
171 	wh = mtod(m, struct ieee80211_frame *);
172 	ieee80211_send_setup(ic, ni, wh,
173 		IEEE80211_FC0_TYPE_MGT | type,
174 		ic->ic_myaddr, ni->ni_macaddr, ni->ni_bssid);
175 	if ((m->m_flags & M_LINK0) != 0 && ni->ni_challenge != NULL) {
176 		m->m_flags &= ~M_LINK0;
177 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
178 			"[%6D] encrypting frame (%s)\n",
179 			wh->i_addr1, ":", __func__);
180 		wh->i_fc[1] |= IEEE80211_FC1_WEP;
181 	}
182 #ifdef IEEE80211_DEBUG
183 	/* avoid printing too many frames */
184 	if ((ieee80211_msg_debug(ic) && doprint(ic, type)) ||
185 	    ieee80211_msg_dumppkts(ic)) {
186 		kprintf("[%6D] send %s on channel %u\n",
187 		    wh->i_addr1, ":",
188 		    ieee80211_mgt_subtype_name[
189 			(type & IEEE80211_FC0_SUBTYPE_MASK) >>
190 				IEEE80211_FC0_SUBTYPE_SHIFT],
191 		    ieee80211_chan2ieee(ic, ic->ic_curchan));
192 	}
193 #endif
194 	IEEE80211_NODE_STAT(ni, tx_mgmt);
195 	IF_ENQUEUE(&ic->ic_mgtq, m);
196 	if (timer) {
197 		/*
198 		 * Set the mgt frame timeout.
199 		 */
200 		ic->ic_mgt_timer = timer;
201 		ifp->if_timer = 1;
202 	}
203 	ifp->if_start(ifp);
204 	return 0;
205 }
206 
207 /*
208  * Send a null data frame to the specified node.
209  *
210  * NB: the caller is assumed to have setup a node reference
211  *     for use; this is necessary to deal with a race condition
212  *     when probing for inactive stations.
213  */
214 int
215 ieee80211_send_nulldata(struct ieee80211_node *ni)
216 {
217 	struct ieee80211com *ic = ni->ni_ic;
218 	struct ifnet *ifp = ic->ic_ifp;
219 	struct mbuf *m;
220 	struct ieee80211_frame *wh;
221 
222 	MGETHDR(m, MB_DONTWAIT, MT_HEADER);
223 	if (m == NULL) {
224 		/* XXX debug msg */
225 		ic->ic_stats.is_tx_nobuf++;
226 		ieee80211_unref_node(&ni);
227 		return ENOMEM;
228 	}
229 	m->m_pkthdr.rcvif = (void *) ni;
230 
231 	wh = mtod(m, struct ieee80211_frame *);
232 	ieee80211_send_setup(ic, ni, wh,
233 		IEEE80211_FC0_TYPE_DATA | IEEE80211_FC0_SUBTYPE_NODATA,
234 		ic->ic_myaddr, ni->ni_macaddr, ni->ni_bssid);
235 	/* NB: power management bit is never sent by an AP */
236 	if ((ni->ni_flags & IEEE80211_NODE_PWR_MGT) &&
237 	    ic->ic_opmode != IEEE80211_M_HOSTAP)
238 		wh->i_fc[1] |= IEEE80211_FC1_PWR_MGT;
239 	m->m_len = m->m_pkthdr.len = sizeof(struct ieee80211_frame);
240 
241 	IEEE80211_NODE_STAT(ni, tx_data);
242 
243 	IEEE80211_DPRINTF(ic, IEEE80211_MSG_DEBUG | IEEE80211_MSG_DUMPPKTS,
244 	    "[%s] send null data frame on channel %u, pwr mgt %s\n",
245 	    ni->ni_macaddr, ":",
246 	    ieee80211_chan2ieee(ic, ic->ic_curchan),
247 	    wh->i_fc[1] & IEEE80211_FC1_PWR_MGT ? "ena" : "dis");
248 
249 	IF_ENQUEUE(&ic->ic_mgtq, m);		/* cheat */
250 	ifp->if_start(ifp);
251 	return 0;
252 }
253 
254 /*
255  * Assign priority to a frame based on any vlan tag assigned
256  * to the station and/or any Diffserv setting in an IP header.
257  * Finally, if an ACM policy is setup (in station mode) it's
258  * applied.
259  */
260 int
261 ieee80211_classify(struct ieee80211com *ic, struct mbuf *m, struct ieee80211_node *ni)
262 {
263 	int v_wme_ac = 0, d_wme_ac, ac;
264 #ifdef INET
265 	struct ether_header *eh;
266 #endif
267 
268 	if ((ni->ni_flags & IEEE80211_NODE_QOS) == 0) {
269 		ac = WME_AC_BE;
270 		goto done;
271 	}
272 
273 #ifdef FREEBSD_VLAN
274 	/*
275 	 * If node has a vlan tag then all traffic
276 	 * to it must have a matching tag.
277 	 */
278 	v_wme_ac = 0;
279 	if (ni->ni_vlan != 0) {
280 		struct m_tag *mtag = VLAN_OUTPUT_TAG(ic->ic_ifp, m);
281 		if (mtag == NULL) {
282 			IEEE80211_NODE_STAT(ni, tx_novlantag);
283 			return 1;
284 		}
285 		if (EVL_VLANOFTAG(VLAN_TAG_VALUE(mtag)) !=
286 		    EVL_VLANOFTAG(ni->ni_vlan)) {
287 			IEEE80211_NODE_STAT(ni, tx_vlanmismatch);
288 			return 1;
289 		}
290 		/* map vlan priority to AC */
291 		switch (EVL_PRIOFTAG(ni->ni_vlan)) {
292 		case 1:
293 		case 2:
294 			v_wme_ac = WME_AC_BK;
295 			break;
296 		case 0:
297 		case 3:
298 			v_wme_ac = WME_AC_BE;
299 			break;
300 		case 4:
301 		case 5:
302 			v_wme_ac = WME_AC_VI;
303 			break;
304 		case 6:
305 		case 7:
306 			v_wme_ac = WME_AC_VO;
307 			break;
308 		}
309 	}
310 #endif	/* FREEBSD_VLAN */
311 
312 #ifdef INET
313 	eh = mtod(m, struct ether_header *);
314 	if (eh->ether_type == htons(ETHERTYPE_IP)) {
315 		const struct ip *ip = (struct ip *)
316 			(mtod(m, uint8_t *) + sizeof (*eh));
317 		/*
318 		 * IP frame, map the TOS field.
319 		 */
320 		switch (ip->ip_tos) {
321 		case 0x08:
322 		case 0x20:
323 			d_wme_ac = WME_AC_BK;	/* background */
324 			break;
325 		case 0x28:
326 		case 0xa0:
327 			d_wme_ac = WME_AC_VI;	/* video */
328 			break;
329 		case 0x30:			/* voice */
330 		case 0xe0:
331 		case 0x88:			/* XXX UPSD */
332 		case 0xb8:
333 			d_wme_ac = WME_AC_VO;
334 			break;
335 		default:
336 			d_wme_ac = WME_AC_BE;
337 			break;
338 		}
339 	} else {
340 #endif /* INET */
341 		d_wme_ac = WME_AC_BE;
342 #ifdef INET
343 	}
344 #endif
345 	/*
346 	 * Use highest priority AC.
347 	 */
348 	if (v_wme_ac > d_wme_ac)
349 		ac = v_wme_ac;
350 	else
351 		ac = d_wme_ac;
352 
353 	/*
354 	 * Apply ACM policy.
355 	 */
356 	if (ic->ic_opmode == IEEE80211_M_STA) {
357 		static const int acmap[4] = {
358 			WME_AC_BK,	/* WME_AC_BE */
359 			WME_AC_BK,	/* WME_AC_BK */
360 			WME_AC_BE,	/* WME_AC_VI */
361 			WME_AC_VI,	/* WME_AC_VO */
362 		};
363 		while (ac != WME_AC_BK &&
364 		    ic->ic_wme.wme_wmeBssChanParams.cap_wmeParams[ac].wmep_acm)
365 			ac = acmap[ac];
366 	}
367 done:
368 	M_WME_SETAC(m, ac);
369 	return 0;
370 }
371 
372 /*
373  * Insure there is sufficient contiguous space to encapsulate the
374  * 802.11 data frame.  If room isn't already there, arrange for it.
375  * Drivers and cipher modules assume we have done the necessary work
376  * and fail rudely if they don't find the space they need.
377  */
378 static struct mbuf *
379 ieee80211_mbuf_adjust(struct ieee80211com *ic, int hdrsize,
380 	struct ieee80211_key *key, struct mbuf *m)
381 {
382 #define	TO_BE_RECLAIMED	(sizeof(struct ether_header) - sizeof(struct llc))
383 	int needed_space = hdrsize;
384 
385 	if (key != NULL) {
386 		/* XXX belongs in crypto code? */
387 		needed_space += key->wk_cipher->ic_header;
388 		/* XXX frags */
389 		/*
390 		 * When crypto is being done in the host we must insure
391 		 * the data are writable for the cipher routines; clone
392 		 * a writable mbuf chain.
393 		 * XXX handle SWMIC specially
394 		 */
395 		if (key->wk_flags & (IEEE80211_KEY_SWCRYPT|IEEE80211_KEY_SWMIC)) {
396 			m = ieee80211_mbuf_clone(m, MB_DONTWAIT);
397 			if (m == NULL) {
398 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
399 				    "%s: cannot get writable mbuf\n", __func__);
400 				ic->ic_stats.is_tx_nobuf++; /* XXX new stat */
401 				return NULL;
402 			}
403 		}
404 	}
405 	/*
406 	 * We know we are called just before stripping an Ethernet
407 	 * header and prepending an LLC header.  This means we know
408 	 * there will be
409 	 *	sizeof(struct ether_header) - sizeof(struct llc)
410 	 * bytes recovered to which we need additional space for the
411 	 * 802.11 header and any crypto header.
412 	 */
413 	/* XXX check trailing space and copy instead? */
414 	if (M_LEADINGSPACE(m) < needed_space - TO_BE_RECLAIMED) {
415 		struct mbuf *n = m_gethdr(MB_DONTWAIT, m->m_type);
416 		if (n == NULL) {
417 			IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
418 			    "%s: cannot expand storage\n", __func__);
419 			ic->ic_stats.is_tx_nobuf++;
420 			m_freem(m);
421 			return NULL;
422 		}
423 		KASSERT(needed_space <= MHLEN,
424 		    ("not enough room, need %u got %zu\n", needed_space, MHLEN));
425 		/*
426 		 * Setup new mbuf to have leading space to prepend the
427 		 * 802.11 header and any crypto header bits that are
428 		 * required (the latter are added when the driver calls
429 		 * back to ieee80211_crypto_encap to do crypto encapsulation).
430 		 */
431 		/* NB: must be first 'cuz it clobbers m_data */
432 		m_move_pkthdr(n, m);
433 		n->m_len = 0;			/* NB: m_gethdr does not set */
434 		n->m_data += needed_space;
435 		/*
436 		 * Pull up Ethernet header to create the expected layout.
437 		 * We could use m_pullup but that's overkill (i.e. we don't
438 		 * need the actual data) and it cannot fail so do it inline
439 		 * for speed.
440 		 */
441 		/* NB: struct ether_header is known to be contiguous */
442 		n->m_len += sizeof(struct ether_header);
443 		m->m_len -= sizeof(struct ether_header);
444 		m->m_data += sizeof(struct ether_header);
445 		/*
446 		 * Replace the head of the chain.
447 		 */
448 		n->m_next = m;
449 		m = n;
450 	}
451 	return m;
452 #undef TO_BE_RECLAIMED
453 }
454 
455 #define	KEY_UNDEFINED(k)	((k).wk_cipher == &ieee80211_cipher_none)
456 /*
457  * Return the transmit key to use in sending a unicast frame.
458  * If a unicast key is set we use that.  When no unicast key is set
459  * we fall back to the default transmit key.
460  */
461 static __inline struct ieee80211_key *
462 ieee80211_crypto_getucastkey(struct ieee80211com *ic, struct ieee80211_node *ni)
463 {
464 	if (KEY_UNDEFINED(ni->ni_ucastkey)) {
465 		if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
466 		    KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
467 			return NULL;
468 		return &ic->ic_nw_keys[ic->ic_def_txkey];
469 	} else {
470 		return &ni->ni_ucastkey;
471 	}
472 }
473 
474 /*
475  * Return the transmit key to use in sending a multicast frame.
476  * Multicast traffic always uses the group key which is installed as
477  * the default tx key.
478  */
479 static __inline struct ieee80211_key *
480 ieee80211_crypto_getmcastkey(struct ieee80211com *ic, struct ieee80211_node *ni)
481 {
482 	if (ic->ic_def_txkey == IEEE80211_KEYIX_NONE ||
483 	    KEY_UNDEFINED(ic->ic_nw_keys[ic->ic_def_txkey]))
484 		return NULL;
485 	return &ic->ic_nw_keys[ic->ic_def_txkey];
486 }
487 
488 /*
489  * Encapsulate an outbound data frame.  The mbuf chain is updated.
490  * If an error is encountered NULL is returned.  The caller is required
491  * to provide a node reference and pullup the ethernet header in the
492  * first mbuf.
493  */
494 struct mbuf *
495 ieee80211_encap(struct ieee80211com *ic, struct mbuf *m,
496 	struct ieee80211_node *ni)
497 {
498 	struct ether_header eh;
499 	struct ieee80211_frame *wh;
500 	struct ieee80211_key *key;
501 	struct llc *llc;
502 	int hdrsize, datalen, addqos;
503 
504 	KASSERT(m->m_len >= sizeof(eh), ("no ethernet header!"));
505 	memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
506 
507 	/*
508 	 * Insure space for additional headers.  First identify
509 	 * transmit key to use in calculating any buffer adjustments
510 	 * required.  This is also used below to do privacy
511 	 * encapsulation work.  Then calculate the 802.11 header
512 	 * size and any padding required by the driver.
513 	 *
514 	 * Note key may be NULL if we fall back to the default
515 	 * transmit key and that is not set.  In that case the
516 	 * buffer may not be expanded as needed by the cipher
517 	 * routines, but they will/should discard it.
518 	 */
519 	if (ic->ic_flags & IEEE80211_F_PRIVACY) {
520 		if (ic->ic_opmode == IEEE80211_M_STA ||
521 		    !IEEE80211_IS_MULTICAST(eh.ether_dhost))
522 			key = ieee80211_crypto_getucastkey(ic, ni);
523 		else
524 			key = ieee80211_crypto_getmcastkey(ic, ni);
525 		if (key == NULL && eh.ether_type != htons(ETHERTYPE_PAE)) {
526 			IEEE80211_DPRINTF(ic, IEEE80211_MSG_CRYPTO,
527 			    "[%6D] no default transmit key (%s) deftxkey %u\n",
528 			    eh.ether_dhost, ":", __func__,
529 			    ic->ic_def_txkey);
530 			ic->ic_stats.is_tx_nodefkey++;
531 		}
532 	} else
533 		key = NULL;
534 	/* XXX 4-address format */
535 	/*
536 	 * XXX Some ap's don't handle QoS-encapsulated EAPOL
537 	 * frames so suppress use.  This may be an issue if other
538 	 * ap's require all data frames to be QoS-encapsulated
539 	 * once negotiated in which case we'll need to make this
540 	 * configurable.
541 	 */
542 	addqos = (ni->ni_flags & IEEE80211_NODE_QOS) &&
543 		 eh.ether_type != htons(ETHERTYPE_PAE);
544 	if (addqos)
545 		hdrsize = sizeof(struct ieee80211_qosframe);
546 	else
547 		hdrsize = sizeof(struct ieee80211_frame);
548 	if (ic->ic_flags & IEEE80211_F_DATAPAD)
549 		hdrsize = roundup(hdrsize, sizeof(uint32_t));
550 	m = ieee80211_mbuf_adjust(ic, hdrsize, key, m);
551 	if (m == NULL) {
552 		/* NB: ieee80211_mbuf_adjust handles msgs+statistics */
553 		goto bad;
554 	}
555 
556 	/* NB: this could be optimized because of ieee80211_mbuf_adjust */
557 	m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
558 	llc = mtod(m, struct llc *);
559 	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
560 	llc->llc_control = LLC_UI;
561 	llc->llc_snap.org_code[0] = 0;
562 	llc->llc_snap.org_code[1] = 0;
563 	llc->llc_snap.org_code[2] = 0;
564 	llc->llc_snap.ether_type = eh.ether_type;
565 	datalen = m->m_pkthdr.len;		/* NB: w/o 802.11 header */
566 
567 	M_PREPEND(m, hdrsize, MB_DONTWAIT);
568 	if (m == NULL) {
569 		ic->ic_stats.is_tx_nobuf++;
570 		goto bad;
571 	}
572 	wh = mtod(m, struct ieee80211_frame *);
573 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
574 	*(uint16_t *)wh->i_dur = 0;
575 	switch (ic->ic_opmode) {
576 	case IEEE80211_M_STA:
577 		wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
578 		IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
579 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
580 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
581 		break;
582 	case IEEE80211_M_IBSS:
583 	case IEEE80211_M_AHDEMO:
584 		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
585 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
586 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
587 		/*
588 		 * NB: always use the bssid from ic_bss as the
589 		 *     neighbor's may be stale after an ibss merge
590 		 */
591 		IEEE80211_ADDR_COPY(wh->i_addr3, ic->ic_bss->ni_bssid);
592 		break;
593 	case IEEE80211_M_HOSTAP:
594 		wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
595 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
596 		IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
597 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
598 		break;
599 	case IEEE80211_M_MONITOR:
600 		goto bad;
601 	}
602 	if (m->m_flags & M_MORE_DATA)
603 		wh->i_fc[1] |= IEEE80211_FC1_MORE_DATA;
604 	if (addqos) {
605 		struct ieee80211_qosframe *qwh =
606 			(struct ieee80211_qosframe *) wh;
607 		int ac, tid;
608 
609 		ac = M_WME_GETAC(m);
610 		/* map from access class/queue to 11e header priorty value */
611 		tid = WME_AC_TO_TID(ac);
612 		qwh->i_qos[0] = tid & IEEE80211_QOS_TID;
613 		if (ic->ic_wme.wme_wmeChanParams.cap_wmeParams[ac].wmep_noackPolicy)
614 			qwh->i_qos[0] |= 1 << IEEE80211_QOS_ACKPOLICY_S;
615 		qwh->i_qos[1] = 0;
616 		qwh->i_fc[0] |= IEEE80211_FC0_SUBTYPE_QOS;
617 
618 		*(uint16_t *)wh->i_seq =
619 		    htole16(ni->ni_txseqs[tid] << IEEE80211_SEQ_SEQ_SHIFT);
620 		ni->ni_txseqs[tid]++;
621 	} else {
622 		*(uint16_t *)wh->i_seq =
623 		    htole16(ni->ni_txseqs[0] << IEEE80211_SEQ_SEQ_SHIFT);
624 		ni->ni_txseqs[0]++;
625 	}
626 	if (key != NULL) {
627 		/*
628 		 * IEEE 802.1X: send EAPOL frames always in the clear.
629 		 * WPA/WPA2: encrypt EAPOL keys when pairwise keys are set.
630 		 */
631 		if (eh.ether_type != htons(ETHERTYPE_PAE) ||
632 		    ((ic->ic_flags & IEEE80211_F_WPA) &&
633 		     (ic->ic_opmode == IEEE80211_M_STA ?
634 		      !KEY_UNDEFINED(*key) : !KEY_UNDEFINED(ni->ni_ucastkey)))) {
635 			wh->i_fc[1] |= IEEE80211_FC1_WEP;
636 			/* XXX do fragmentation */
637 			if (!ieee80211_crypto_enmic(ic, key, m, 0)) {
638 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
639 				    "[%6D] enmic failed, discard frame\n",
640 				    eh.ether_dhost, ":");
641 				ic->ic_stats.is_crypto_enmicfail++;
642 				goto bad;
643 			}
644 		}
645 	}
646 
647 	IEEE80211_NODE_STAT(ni, tx_data);
648 	if (IEEE80211_IS_MULTICAST(wh->i_addr1))
649 		IEEE80211_NODE_STAT(ni, tx_mcast);
650 	else
651 		IEEE80211_NODE_STAT(ni, tx_ucast);
652 	IEEE80211_NODE_STAT_ADD(ni, tx_bytes, datalen);
653 
654 	return m;
655 bad:
656 	if (m != NULL)
657 		m_freem(m);
658 	return NULL;
659 }
660 
661 /*
662  * Add a supported rates element id to a frame.
663  */
664 uint8_t *
665 ieee80211_add_rates(uint8_t *frm, const struct ieee80211_rateset *rs)
666 {
667 	int nrates;
668 
669 	*frm++ = IEEE80211_ELEMID_RATES;
670 	nrates = rs->rs_nrates;
671 	if (nrates > IEEE80211_RATE_SIZE)
672 		nrates = IEEE80211_RATE_SIZE;
673 	*frm++ = nrates;
674 	memcpy(frm, rs->rs_rates, nrates);
675 	return frm + nrates;
676 }
677 
678 /*
679  * Add an extended supported rates element id to a frame.
680  */
681 uint8_t *
682 ieee80211_add_xrates(uint8_t *frm, const struct ieee80211_rateset *rs)
683 {
684 	/*
685 	 * Add an extended supported rates element if operating in 11g mode.
686 	 */
687 	if (rs->rs_nrates > IEEE80211_RATE_SIZE) {
688 		int nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
689 		*frm++ = IEEE80211_ELEMID_XRATES;
690 		*frm++ = nrates;
691 		memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
692 		frm += nrates;
693 	}
694 	return frm;
695 }
696 
697 /*
698  * Add an ssid elemet to a frame.
699  */
700 uint8_t *
701 ieee80211_add_ssid(uint8_t *frm, const uint8_t *ssid, u_int len)
702 {
703 	*frm++ = IEEE80211_ELEMID_SSID;
704 	*frm++ = len;
705 	memcpy(frm, ssid, len);
706 	return frm + len;
707 }
708 
709 /*
710  * Add an erp element to a frame.
711  */
712 static uint8_t *
713 ieee80211_add_erp(uint8_t *frm, struct ieee80211com *ic)
714 {
715 	uint8_t erp;
716 
717 	*frm++ = IEEE80211_ELEMID_ERP;
718 	*frm++ = 1;
719 	erp = 0;
720 	if (ic->ic_nonerpsta != 0)
721 		erp |= IEEE80211_ERP_NON_ERP_PRESENT;
722 	if (ic->ic_flags & IEEE80211_F_USEPROT)
723 		erp |= IEEE80211_ERP_USE_PROTECTION;
724 	if (ic->ic_flags & IEEE80211_F_USEBARKER)
725 		erp |= IEEE80211_ERP_LONG_PREAMBLE;
726 	*frm++ = erp;
727 	return frm;
728 }
729 
730 static uint8_t *
731 ieee80211_setup_wpa_ie(struct ieee80211com *ic, uint8_t *ie)
732 {
733 #define	WPA_OUI_BYTES		0x00, 0x50, 0xf2
734 #define	ADDSHORT(frm, v) do {			\
735 	frm[0] = (v) & 0xff;			\
736 	frm[1] = (v) >> 8;			\
737 	frm += 2;				\
738 } while (0)
739 #define	ADDSELECTOR(frm, sel) do {		\
740 	memcpy(frm, sel, 4);			\
741 	frm += 4;				\
742 } while (0)
743 	static const uint8_t oui[4] = { WPA_OUI_BYTES, WPA_OUI_TYPE };
744 	static const uint8_t cipher_suite[][4] = {
745 		{ WPA_OUI_BYTES, WPA_CSE_WEP40 },	/* NB: 40-bit */
746 		{ WPA_OUI_BYTES, WPA_CSE_TKIP },
747 		{ 0x00, 0x00, 0x00, 0x00 },		/* XXX WRAP */
748 		{ WPA_OUI_BYTES, WPA_CSE_CCMP },
749 		{ 0x00, 0x00, 0x00, 0x00 },		/* XXX CKIP */
750 		{ WPA_OUI_BYTES, WPA_CSE_NULL },
751 	};
752 	static const uint8_t wep104_suite[4] =
753 		{ WPA_OUI_BYTES, WPA_CSE_WEP104 };
754 	static const uint8_t key_mgt_unspec[4] =
755 		{ WPA_OUI_BYTES, WPA_ASE_8021X_UNSPEC };
756 	static const uint8_t key_mgt_psk[4] =
757 		{ WPA_OUI_BYTES, WPA_ASE_8021X_PSK };
758 	const struct ieee80211_rsnparms *rsn = &ic->ic_bss->ni_rsn;
759 	uint8_t *frm = ie;
760 	uint8_t *selcnt;
761 
762 	*frm++ = IEEE80211_ELEMID_VENDOR;
763 	*frm++ = 0;				/* length filled in below */
764 	memcpy(frm, oui, sizeof(oui));		/* WPA OUI */
765 	frm += sizeof(oui);
766 	ADDSHORT(frm, WPA_VERSION);
767 
768 	/* XXX filter out CKIP */
769 
770 	/* multicast cipher */
771 	if (rsn->rsn_mcastcipher == IEEE80211_CIPHER_WEP &&
772 	    rsn->rsn_mcastkeylen >= 13)
773 		ADDSELECTOR(frm, wep104_suite);
774 	else
775 		ADDSELECTOR(frm, cipher_suite[rsn->rsn_mcastcipher]);
776 
777 	/* unicast cipher list */
778 	selcnt = frm;
779 	ADDSHORT(frm, 0);			/* selector count */
780 	if (rsn->rsn_ucastcipherset & (1<<IEEE80211_CIPHER_AES_CCM)) {
781 		selcnt[0]++;
782 		ADDSELECTOR(frm, cipher_suite[IEEE80211_CIPHER_AES_CCM]);
783 	}
784 	if (rsn->rsn_ucastcipherset & (1<<IEEE80211_CIPHER_TKIP)) {
785 		selcnt[0]++;
786 		ADDSELECTOR(frm, cipher_suite[IEEE80211_CIPHER_TKIP]);
787 	}
788 
789 	/* authenticator selector list */
790 	selcnt = frm;
791 	ADDSHORT(frm, 0);			/* selector count */
792 	if (rsn->rsn_keymgmtset & WPA_ASE_8021X_UNSPEC) {
793 		selcnt[0]++;
794 		ADDSELECTOR(frm, key_mgt_unspec);
795 	}
796 	if (rsn->rsn_keymgmtset & WPA_ASE_8021X_PSK) {
797 		selcnt[0]++;
798 		ADDSELECTOR(frm, key_mgt_psk);
799 	}
800 
801 	/* optional capabilities */
802 	if (rsn->rsn_caps != 0 && rsn->rsn_caps != RSN_CAP_PREAUTH)
803 		ADDSHORT(frm, rsn->rsn_caps);
804 
805 	/* calculate element length */
806 	ie[1] = frm - ie - 2;
807 	KASSERT(ie[1]+2 <= sizeof(struct ieee80211_ie_wpa),
808 		("WPA IE too big, %u > %zu",
809 		ie[1]+2, sizeof(struct ieee80211_ie_wpa)));
810 	return frm;
811 #undef ADDSHORT
812 #undef ADDSELECTOR
813 #undef WPA_OUI_BYTES
814 }
815 
816 static uint8_t *
817 ieee80211_setup_rsn_ie(struct ieee80211com *ic, uint8_t *ie)
818 {
819 #define	RSN_OUI_BYTES		0x00, 0x0f, 0xac
820 #define	ADDSHORT(frm, v) do {			\
821 	frm[0] = (v) & 0xff;			\
822 	frm[1] = (v) >> 8;			\
823 	frm += 2;				\
824 } while (0)
825 #define	ADDSELECTOR(frm, sel) do {		\
826 	memcpy(frm, sel, 4);			\
827 	frm += 4;				\
828 } while (0)
829 	static const uint8_t cipher_suite[][4] = {
830 		{ RSN_OUI_BYTES, RSN_CSE_WEP40 },	/* NB: 40-bit */
831 		{ RSN_OUI_BYTES, RSN_CSE_TKIP },
832 		{ RSN_OUI_BYTES, RSN_CSE_WRAP },
833 		{ RSN_OUI_BYTES, RSN_CSE_CCMP },
834 		{ 0x00, 0x00, 0x00, 0x00 },		/* XXX CKIP */
835 		{ RSN_OUI_BYTES, RSN_CSE_NULL },
836 	};
837 	static const uint8_t wep104_suite[4] =
838 		{ RSN_OUI_BYTES, RSN_CSE_WEP104 };
839 	static const uint8_t key_mgt_unspec[4] =
840 		{ RSN_OUI_BYTES, RSN_ASE_8021X_UNSPEC };
841 	static const uint8_t key_mgt_psk[4] =
842 		{ RSN_OUI_BYTES, RSN_ASE_8021X_PSK };
843 	const struct ieee80211_rsnparms *rsn = &ic->ic_bss->ni_rsn;
844 	uint8_t *frm = ie;
845 	uint8_t *selcnt;
846 
847 	*frm++ = IEEE80211_ELEMID_RSN;
848 	*frm++ = 0;				/* length filled in below */
849 	ADDSHORT(frm, RSN_VERSION);
850 
851 	/* XXX filter out CKIP */
852 
853 	/* multicast cipher */
854 	if (rsn->rsn_mcastcipher == IEEE80211_CIPHER_WEP &&
855 	    rsn->rsn_mcastkeylen >= 13)
856 		ADDSELECTOR(frm, wep104_suite);
857 	else
858 		ADDSELECTOR(frm, cipher_suite[rsn->rsn_mcastcipher]);
859 
860 	/* unicast cipher list */
861 	selcnt = frm;
862 	ADDSHORT(frm, 0);			/* selector count */
863 	if (rsn->rsn_ucastcipherset & (1<<IEEE80211_CIPHER_AES_CCM)) {
864 		selcnt[0]++;
865 		ADDSELECTOR(frm, cipher_suite[IEEE80211_CIPHER_AES_CCM]);
866 	}
867 	if (rsn->rsn_ucastcipherset & (1<<IEEE80211_CIPHER_TKIP)) {
868 		selcnt[0]++;
869 		ADDSELECTOR(frm, cipher_suite[IEEE80211_CIPHER_TKIP]);
870 	}
871 
872 	/* authenticator selector list */
873 	selcnt = frm;
874 	ADDSHORT(frm, 0);			/* selector count */
875 	if (rsn->rsn_keymgmtset & WPA_ASE_8021X_UNSPEC) {
876 		selcnt[0]++;
877 		ADDSELECTOR(frm, key_mgt_unspec);
878 	}
879 	if (rsn->rsn_keymgmtset & WPA_ASE_8021X_PSK) {
880 		selcnt[0]++;
881 		ADDSELECTOR(frm, key_mgt_psk);
882 	}
883 
884 	/* optional capabilities */
885 	ADDSHORT(frm, rsn->rsn_caps);
886 	/* XXX PMKID */
887 
888 	/* calculate element length */
889 	ie[1] = frm - ie - 2;
890 	KASSERT(ie[1]+2 <= sizeof(struct ieee80211_ie_wpa),
891 		("RSN IE too big, %u > %zu",
892 		ie[1]+2, sizeof(struct ieee80211_ie_wpa)));
893 	return frm;
894 #undef ADDSELECTOR
895 #undef ADDSHORT
896 #undef RSN_OUI_BYTES
897 }
898 
899 /*
900  * Add a WPA/RSN element to a frame.
901  */
902 static uint8_t *
903 ieee80211_add_wpa(uint8_t *frm, struct ieee80211com *ic)
904 {
905 
906 	KASSERT(ic->ic_flags & IEEE80211_F_WPA, ("no WPA/RSN!"));
907 	if (ic->ic_flags & IEEE80211_F_WPA2)
908 		frm = ieee80211_setup_rsn_ie(ic, frm);
909 	if (ic->ic_flags & IEEE80211_F_WPA1)
910 		frm = ieee80211_setup_wpa_ie(ic, frm);
911 	return frm;
912 }
913 
914 #define	WME_OUI_BYTES		0x00, 0x50, 0xf2
915 /*
916  * Add a WME information element to a frame.
917  */
918 static uint8_t *
919 ieee80211_add_wme_info(uint8_t *frm, struct ieee80211_wme_state *wme)
920 {
921 	static const struct ieee80211_wme_info info = {
922 		.wme_id		= IEEE80211_ELEMID_VENDOR,
923 		.wme_len	= sizeof(struct ieee80211_wme_info) - 2,
924 		.wme_oui	= { WME_OUI_BYTES },
925 		.wme_type	= WME_OUI_TYPE,
926 		.wme_subtype	= WME_INFO_OUI_SUBTYPE,
927 		.wme_version	= WME_VERSION,
928 		.wme_info	= 0,
929 	};
930 	memcpy(frm, &info, sizeof(info));
931 	return frm + sizeof(info);
932 }
933 
934 /*
935  * Add a WME parameters element to a frame.
936  */
937 static uint8_t *
938 ieee80211_add_wme_param(uint8_t *frm, struct ieee80211_wme_state *wme)
939 {
940 #define	SM(_v, _f)	(((_v) << _f##_S) & _f)
941 #define	ADDSHORT(frm, v) do {			\
942 	frm[0] = (v) & 0xff;			\
943 	frm[1] = (v) >> 8;			\
944 	frm += 2;				\
945 } while (0)
946 	/* NB: this works 'cuz a param has an info at the front */
947 	static const struct ieee80211_wme_info param = {
948 		.wme_id		= IEEE80211_ELEMID_VENDOR,
949 		.wme_len	= sizeof(struct ieee80211_wme_param) - 2,
950 		.wme_oui	= { WME_OUI_BYTES },
951 		.wme_type	= WME_OUI_TYPE,
952 		.wme_subtype	= WME_PARAM_OUI_SUBTYPE,
953 		.wme_version	= WME_VERSION,
954 	};
955 	int i;
956 
957 	memcpy(frm, &param, sizeof(param));
958 	frm += __offsetof(struct ieee80211_wme_info, wme_info);
959 	*frm++ = wme->wme_bssChanParams.cap_info;	/* AC info */
960 	*frm++ = 0;					/* reserved field */
961 	for (i = 0; i < WME_NUM_AC; i++) {
962 		const struct wmeParams *ac =
963 		       &wme->wme_bssChanParams.cap_wmeParams[i];
964 		*frm++ = SM(i, WME_PARAM_ACI)
965 		       | SM(ac->wmep_acm, WME_PARAM_ACM)
966 		       | SM(ac->wmep_aifsn, WME_PARAM_AIFSN)
967 		       ;
968 		*frm++ = SM(ac->wmep_logcwmax, WME_PARAM_LOGCWMAX)
969 		       | SM(ac->wmep_logcwmin, WME_PARAM_LOGCWMIN)
970 		       ;
971 		ADDSHORT(frm, ac->wmep_txopLimit);
972 	}
973 	return frm;
974 #undef SM
975 #undef ADDSHORT
976 }
977 #undef WME_OUI_BYTES
978 
979 /*
980  * Send a probe request frame with the specified ssid
981  * and any optional information element data.
982  */
983 int
984 ieee80211_send_probereq(struct ieee80211_node *ni,
985 	const uint8_t sa[IEEE80211_ADDR_LEN],
986 	const uint8_t da[IEEE80211_ADDR_LEN],
987 	const uint8_t bssid[IEEE80211_ADDR_LEN],
988 	const uint8_t *ssid, size_t ssidlen,
989 	const void *optie, size_t optielen)
990 {
991 	struct ieee80211com *ic = ni->ni_ic;
992 	struct ifnet *ifp = ic->ic_ifp;
993 	enum ieee80211_phymode mode;
994 	struct ieee80211_frame *wh;
995 	struct ieee80211_rateset rs;
996 	struct mbuf *m;
997 	uint8_t *frm;
998 
999 	/*
1000 	 * Hold a reference on the node so it doesn't go away until after
1001 	 * the xmit is complete all the way in the driver.  On error we
1002 	 * will remove our reference.
1003 	 */
1004 	IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
1005 		"ieee80211_ref_node (%s:%u) %p<%6D> refcnt %d\n",
1006 		__func__, __LINE__,
1007 		ni, ni->ni_macaddr, ":",
1008 		ieee80211_node_refcnt(ni) + 1);
1009 	ieee80211_ref_node(ni);
1010 
1011 	/*
1012 	 * prreq frame format
1013 	 *	[tlv] ssid
1014 	 *	[tlv] supported rates
1015 	 *	[tlv] extended supported rates
1016 	 *	[tlv] user-specified ie's
1017 	 */
1018 	m = ieee80211_getmgtframe(&frm,
1019 		 2 + IEEE80211_NWID_LEN
1020 	       + 2 + IEEE80211_RATE_SIZE
1021 	       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE)
1022 	       + (optie != NULL ? optielen : 0)
1023 	);
1024 	if (m == NULL) {
1025 		ic->ic_stats.is_tx_nobuf++;
1026 		ieee80211_free_node(ni);
1027 		return ENOMEM;
1028 	}
1029 
1030 	frm = ieee80211_add_ssid(frm, ssid, ssidlen);
1031 
1032 	/*
1033 	 * XXX
1034 	 * Clear basic rates.
1035 	 *
1036 	 * Though according to 802.11 standard: MSB of each supported rate
1037 	 * octet in (Extended) Supported Rates ie of probe requests should
1038 	 * be ignored, some HostAP implementations still check it ...
1039 	 */
1040 	mode = ieee80211_chan2mode(ic, ic->ic_curchan);
1041 	rs = ic->ic_sup_rates[mode];
1042 	ieee80211_set_basicrates(&rs, IEEE80211_MODE_AUTO, 0);
1043 	frm = ieee80211_add_rates(frm, &rs);
1044 	frm = ieee80211_add_xrates(frm, &rs);
1045 
1046 	if (optie != NULL) {
1047 		memcpy(frm, optie, optielen);
1048 		frm += optielen;
1049 	}
1050 	m->m_pkthdr.len = m->m_len = frm - mtod(m, uint8_t *);
1051 
1052 	M_PREPEND(m, sizeof(struct ieee80211_frame), MB_DONTWAIT);
1053 	if (m == NULL)
1054 		return ENOMEM;
1055 	KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
1056 	m->m_pkthdr.rcvif = (void *)ni;
1057 
1058 	wh = mtod(m, struct ieee80211_frame *);
1059 	ieee80211_send_setup(ic, ni, wh,
1060 		IEEE80211_FC0_TYPE_MGT | IEEE80211_FC0_SUBTYPE_PROBE_REQ,
1061 		sa, da, bssid);
1062 	/* XXX power management? */
1063 
1064 	IEEE80211_NODE_STAT(ni, tx_probereq);
1065 	IEEE80211_NODE_STAT(ni, tx_mgmt);
1066 
1067 	IEEE80211_DPRINTF(ic, IEEE80211_MSG_DEBUG | IEEE80211_MSG_DUMPPKTS,
1068 	    "[%6D] send probe req on channel %u\n",
1069 	    wh->i_addr1, ":",
1070 	    ieee80211_chan2ieee(ic, ic->ic_curchan));
1071 
1072 	IF_ENQUEUE(&ic->ic_mgtq, m);
1073 	ifp->if_start(ifp);
1074 	return 0;
1075 }
1076 
1077 /*
1078  * Calculate capability information for mgt frames.
1079  */
1080 static uint16_t
1081 getcapinfo(struct ieee80211com *ic, struct ieee80211_channel *chan)
1082 {
1083 	uint16_t capinfo;
1084 
1085 	KASSERT(ic->ic_opmode != IEEE80211_M_STA, ("station mode"));
1086 
1087 	if (ic->ic_opmode == IEEE80211_M_HOSTAP)
1088 		capinfo = IEEE80211_CAPINFO_ESS;
1089 	else if (ic->ic_opmode == IEEE80211_M_IBSS)
1090 		capinfo = IEEE80211_CAPINFO_IBSS;
1091 	else
1092 		capinfo = 0;
1093 	if (ic->ic_flags & IEEE80211_F_PRIVACY)
1094 		capinfo |= IEEE80211_CAPINFO_PRIVACY;
1095 	if (IEEE80211_IS_CHAN_2GHZ(chan)) {
1096 		if (ic->ic_flags & IEEE80211_F_SHPREAMBLE)
1097 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
1098 		if (ic->ic_caps_ext & IEEE80211_CEXT_PBCC)
1099 			capinfo |= IEEE80211_CAPINFO_PBCC;
1100 	}
1101 	if (ic->ic_flags & IEEE80211_F_SHSLOT)
1102 		capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
1103 	return capinfo;
1104 }
1105 
1106 static struct mbuf *
1107 _ieee80211_probe_resp_alloc(struct ieee80211com *ic, struct ieee80211_node *ni)
1108 {
1109 	const struct ieee80211_rateset *rs;
1110 	uint16_t capinfo;
1111 	struct mbuf *m;
1112 	uint8_t *frm;
1113 	int pktlen;
1114 
1115 	/*
1116 	 * probe response frame format
1117 	 *	[8] time stamp
1118 	 *	[2] beacon interval
1119 	 *	[2] cabability information
1120 	 *	[tlv] ssid
1121 	 *	[tlv] supported rates
1122 	 *	[tlv] parameter set (FH/DS)
1123 	 *	[4] parameter set (IBSS)
1124 	 *	[tlv] extended rate phy (ERP)
1125 	 *	[tlv] extended supported rates
1126 	 *	[tlv] WPA
1127 	 *	[tlv] WME (optional)
1128 	 */
1129 	KKASSERT(ic->ic_curmode != IEEE80211_MODE_AUTO);
1130 	rs = &ic->ic_sup_rates[ic->ic_curmode];
1131 	pktlen =  8					/* time stamp */
1132 		+ sizeof(uint16_t)			/* beacon interval */
1133 		+ sizeof(uint16_t)			/* capabilities */
1134 		+ 2 + ni->ni_esslen			/* ssid */
1135 		+ 2 + IEEE80211_RATE_SIZE		/* supported rates */
1136 		+ 2 + 5 /* max(5,1) */			/* DS/FH parameters */
1137 		+ 2 + 2					/* IBSS parameters */
1138 		+ 2 + 1					/* ERP */
1139 		+ 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE)
1140 		/* XXX !WPA1+WPA2 fits w/o a cluster */
1141 		+ (ic->ic_flags & IEEE80211_F_WPA ?	/* WPA 1+2 */
1142 		 	2*sizeof(struct ieee80211_ie_wpa) : 0)
1143 		+ sizeof(struct ieee80211_wme_param);	/* WME */
1144 
1145 	m = ieee80211_getmgtframe(&frm, pktlen);
1146 	if (m == NULL) {
1147 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
1148 			"%s: cannot get buf; size %u\n", __func__, pktlen);
1149 		ic->ic_stats.is_tx_nobuf++;
1150 		return NULL;
1151 	}
1152 
1153 	memset(frm, 0, 8);	/* timestamp should be filled later */
1154 	frm += 8;
1155 	*(uint16_t *)frm = htole16(ni->ni_intval);
1156 	frm += 2;
1157 	capinfo = getcapinfo(ic, ni->ni_chan);
1158 	*(uint16_t *)frm = htole16(capinfo);
1159 	frm += 2;
1160 
1161 	frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
1162 	frm = ieee80211_add_rates(frm, rs);
1163 
1164 	if (ic->ic_phytype == IEEE80211_T_FH) {
1165 		*frm++ = IEEE80211_ELEMID_FHPARMS;
1166 		*frm++ = 5;
1167 		*frm++ = ni->ni_fhdwell & 0x00ff;
1168 		*frm++ = (ni->ni_fhdwell >> 8) & 0x00ff;
1169 		*frm++ = IEEE80211_FH_CHANSET(
1170 		    ieee80211_chan2ieee(ic, ni->ni_chan));
1171 		*frm++ = IEEE80211_FH_CHANPAT(
1172 		    ieee80211_chan2ieee(ic, ni->ni_chan));
1173 		*frm++ = ni->ni_fhindex;
1174 	} else {
1175 		*frm++ = IEEE80211_ELEMID_DSPARMS;
1176 		*frm++ = 1;
1177 		*frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
1178 	}
1179 
1180 	if (ic->ic_opmode == IEEE80211_M_IBSS) {
1181 		*frm++ = IEEE80211_ELEMID_IBSSPARMS;
1182 		*frm++ = 2;
1183 		*frm++ = 0; *frm++ = 0;		/* TODO: ATIM window */
1184 	}
1185 	if (ic->ic_flags & IEEE80211_F_WPA)
1186 		frm = ieee80211_add_wpa(frm, ic);
1187 	if (ic->ic_curmode == IEEE80211_MODE_11G)
1188 		frm = ieee80211_add_erp(frm, ic);
1189 	frm = ieee80211_add_xrates(frm, rs);
1190 	if (ic->ic_flags & IEEE80211_F_WME)
1191 		frm = ieee80211_add_wme_param(frm, &ic->ic_wme);
1192 	m->m_pkthdr.len = m->m_len = frm - mtod(m, uint8_t *);
1193 	KKASSERT(m->m_len <= pktlen);
1194 
1195 	return m;
1196 }
1197 
1198 /*
1199  * Send a management frame.  The node is for the destination (or ic_bss
1200  * when in station mode).  Nodes other than ic_bss have their reference
1201  * count bumped to reflect our use for an indeterminant time.
1202  */
1203 int
1204 ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
1205 	int type, int arg)
1206 {
1207 #define	senderr(_x, _v)	do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
1208 	struct mbuf *m;
1209 	uint8_t *frm;
1210 	uint16_t capinfo;
1211 	int has_challenge, is_shared_key, ret, timer, status;
1212 	const struct ieee80211_rateset *rs;
1213 
1214 	KASSERT(ni != NULL, ("null node"));
1215 
1216 	/*
1217 	 * Hold a reference on the node so it doesn't go away until after
1218 	 * the xmit is complete all the way in the driver.  On error we
1219 	 * will remove our reference.
1220 	 */
1221 	IEEE80211_DPRINTF(ic, IEEE80211_MSG_NODE,
1222 		"ieee80211_ref_node (%s:%u) %p<%6D> refcnt %d\n",
1223 		__func__, __LINE__,
1224 		ni, ni->ni_macaddr, ":",
1225 		ieee80211_node_refcnt(ni) + 1);
1226 	ieee80211_ref_node(ni);
1227 
1228 	timer = 0;
1229 	switch (type) {
1230 	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
1231 		m = _ieee80211_probe_resp_alloc(ic, ic->ic_bss);
1232 		if (m == NULL) {
1233 			/* NB: Statistics have been updated. */
1234 			ret = ENOMEM;
1235 			goto bad;
1236 		}
1237 		break;
1238 
1239 	case IEEE80211_FC0_SUBTYPE_AUTH:
1240 		status = arg >> 16;
1241 		arg &= 0xffff;
1242 		has_challenge = ((arg == IEEE80211_AUTH_SHARED_CHALLENGE ||
1243 		    arg == IEEE80211_AUTH_SHARED_RESPONSE) &&
1244 		    ni->ni_challenge != NULL);
1245 
1246 		/*
1247 		 * Deduce whether we're doing open authentication or
1248 		 * shared key authentication.  We do the latter if
1249 		 * we're in the middle of a shared key authentication
1250 		 * handshake or if we're initiating an authentication
1251 		 * request and configured to use shared key.
1252 		 */
1253 		is_shared_key = has_challenge ||
1254 		     arg >= IEEE80211_AUTH_SHARED_RESPONSE ||
1255 		     (arg == IEEE80211_AUTH_SHARED_REQUEST &&
1256 		      ic->ic_bss->ni_authmode == IEEE80211_AUTH_SHARED);
1257 
1258 		m = ieee80211_getmgtframe(&frm,
1259 			  3 * sizeof(uint16_t)
1260 			+ (has_challenge && status == IEEE80211_STATUS_SUCCESS ?
1261 				sizeof(uint16_t)+IEEE80211_CHALLENGE_LEN : 0)
1262 		);
1263 		if (m == NULL)
1264 			senderr(ENOMEM, is_tx_nobuf);
1265 
1266 		((uint16_t *)frm)[0] =
1267 		    (is_shared_key) ? htole16(IEEE80211_AUTH_ALG_SHARED)
1268 		                    : htole16(IEEE80211_AUTH_ALG_OPEN);
1269 		((uint16_t *)frm)[1] = htole16(arg);	/* sequence number */
1270 		((uint16_t *)frm)[2] = htole16(status);/* status */
1271 
1272 		if (has_challenge && status == IEEE80211_STATUS_SUCCESS) {
1273 			((uint16_t *)frm)[3] =
1274 			    htole16((IEEE80211_CHALLENGE_LEN << 8) |
1275 			    IEEE80211_ELEMID_CHALLENGE);
1276 			memcpy(&((uint16_t *)frm)[4], ni->ni_challenge,
1277 			    IEEE80211_CHALLENGE_LEN);
1278 			m->m_pkthdr.len = m->m_len =
1279 				4 * sizeof(uint16_t) + IEEE80211_CHALLENGE_LEN;
1280 			if (arg == IEEE80211_AUTH_SHARED_RESPONSE) {
1281 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
1282 				    "[%6D] request encrypt frame (%s)\n",
1283 				    ni->ni_macaddr, ":", __func__);
1284 				m->m_flags |= M_LINK0; /* WEP-encrypt, please */
1285 			}
1286 		} else
1287 			m->m_pkthdr.len = m->m_len = 3 * sizeof(uint16_t);
1288 
1289 		/* XXX not right for shared key */
1290 		if (status == IEEE80211_STATUS_SUCCESS)
1291 			IEEE80211_NODE_STAT(ni, tx_auth);
1292 		else
1293 			IEEE80211_NODE_STAT(ni, tx_auth_fail);
1294 
1295 		if (ic->ic_opmode == IEEE80211_M_STA)
1296 			timer = IEEE80211_TRANS_WAIT;
1297 		break;
1298 
1299 	case IEEE80211_FC0_SUBTYPE_DEAUTH:
1300 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
1301 			"[%6D] send station deauthenticate (reason %d)\n",
1302 			ni->ni_macaddr, ":", arg);
1303 		m = ieee80211_getmgtframe(&frm, sizeof(uint16_t));
1304 		if (m == NULL)
1305 			senderr(ENOMEM, is_tx_nobuf);
1306 		*(uint16_t *)frm = htole16(arg);	/* reason */
1307 		m->m_pkthdr.len = m->m_len = sizeof(uint16_t);
1308 
1309 		IEEE80211_NODE_STAT(ni, tx_deauth);
1310 		IEEE80211_NODE_STAT_SET(ni, tx_deauth_code, arg);
1311 
1312 		ieee80211_node_unauthorize(ni);		/* port closed */
1313 		break;
1314 
1315 	case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
1316 	case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
1317 		/*
1318 		 * asreq frame format
1319 		 *	[2] capability information
1320 		 *	[2] listen interval
1321 		 *	[6*] current AP address (reassoc only)
1322 		 *	[tlv] ssid
1323 		 *	[tlv] supported rates
1324 		 *	[tlv] extended supported rates
1325 		 *	[tlv] WME
1326 		 *	[tlv] user-specified ie's
1327 		 */
1328 		m = ieee80211_getmgtframe(&frm,
1329 			 sizeof(uint16_t)
1330 		       + sizeof(uint16_t)
1331 		       + IEEE80211_ADDR_LEN
1332 		       + 2 + IEEE80211_NWID_LEN
1333 		       + 2 + IEEE80211_RATE_SIZE
1334 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE)
1335 		       + sizeof(struct ieee80211_wme_info)
1336 		       + (ic->ic_opt_ie != NULL ? ic->ic_opt_ie_len : 0)
1337 		);
1338 		if (m == NULL)
1339 			senderr(ENOMEM, is_tx_nobuf);
1340 
1341 		KASSERT(ic->ic_opmode == IEEE80211_M_STA,
1342 		    ("wrong mode %u", ic->ic_opmode));
1343 		capinfo = IEEE80211_CAPINFO_ESS;
1344 		if (ic->ic_flags & IEEE80211_F_PRIVACY)
1345 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
1346 		/*
1347 		 * NB: Some 11a AP's reject the request when
1348 		 *     short premable or PBCC modulation is set.
1349 		 */
1350 		if (IEEE80211_IS_CHAN_2GHZ(ic->ic_curchan)) {
1351 			if (ic->ic_caps & IEEE80211_C_SHPREAMBLE)
1352 				capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
1353 			if (ic->ic_caps_ext & IEEE80211_CEXT_PBCC)
1354 				capinfo |= IEEE80211_CAPINFO_PBCC;
1355 		}
1356 		if ((ni->ni_capinfo & IEEE80211_CAPINFO_SHORT_SLOTTIME) &&
1357 		    (ic->ic_caps & IEEE80211_C_SHSLOT))
1358 			capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
1359 		*(uint16_t *)frm = htole16(capinfo);
1360 		frm += 2;
1361 
1362 		*(uint16_t *)frm = htole16(ic->ic_lintval);
1363 		frm += 2;
1364 
1365 		if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
1366 			IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
1367 			frm += IEEE80211_ADDR_LEN;
1368 		}
1369 
1370 		frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
1371 
1372 		rs = &ic->ic_sup_rates[ieee80211_chan2mode(ic, ni->ni_chan)];
1373 		frm = ieee80211_add_rates(frm, rs);
1374 		frm = ieee80211_add_xrates(frm, rs);
1375 
1376 		if ((ic->ic_flags & IEEE80211_F_WME) && ni->ni_wme_ie != NULL)
1377 			frm = ieee80211_add_wme_info(frm, &ic->ic_wme);
1378 		if (ic->ic_opt_ie != NULL) {
1379 			memcpy(frm, ic->ic_opt_ie, ic->ic_opt_ie_len);
1380 			frm += ic->ic_opt_ie_len;
1381 		}
1382 		m->m_pkthdr.len = m->m_len = frm - mtod(m, uint8_t *);
1383 
1384 		timer = IEEE80211_TRANS_WAIT;
1385 		break;
1386 
1387 	case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
1388 	case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
1389 		/*
1390 		 * asreq frame format
1391 		 *	[2] capability information
1392 		 *	[2] status
1393 		 *	[2] association ID
1394 		 *	[tlv] supported rates
1395 		 *	[tlv] extended supported rates
1396 		 *	[tlv] WME (if enabled and STA enabled)
1397 		 */
1398 		m = ieee80211_getmgtframe(&frm,
1399 			 sizeof(uint16_t)
1400 		       + sizeof(uint16_t)
1401 		       + sizeof(uint16_t)
1402 		       + 2 + IEEE80211_RATE_SIZE
1403 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE)
1404 		       + sizeof(struct ieee80211_wme_param)
1405 		);
1406 		if (m == NULL)
1407 			senderr(ENOMEM, is_tx_nobuf);
1408 
1409 		capinfo = getcapinfo(ic, ic->ic_curchan);
1410 		*(uint16_t *)frm = htole16(capinfo);
1411 		frm += 2;
1412 
1413 		*(uint16_t *)frm = htole16(arg);	/* status */
1414 		frm += 2;
1415 
1416 		if (arg == IEEE80211_STATUS_SUCCESS) {
1417 			*(uint16_t *)frm = htole16(ni->ni_associd);
1418 			IEEE80211_NODE_STAT(ni, tx_assoc);
1419 		} else
1420 			IEEE80211_NODE_STAT(ni, tx_assoc_fail);
1421 		frm += 2;
1422 
1423 		KKASSERT(ic->ic_curmode != IEEE80211_MODE_AUTO);
1424 		rs = &ic->ic_sup_rates[ic->ic_curmode];
1425 		frm = ieee80211_add_rates(frm, rs);
1426 		frm = ieee80211_add_xrates(frm, rs);
1427 		if ((ic->ic_flags & IEEE80211_F_WME) && ni->ni_wme_ie != NULL)
1428 			frm = ieee80211_add_wme_param(frm, &ic->ic_wme);
1429 		m->m_pkthdr.len = m->m_len = frm - mtod(m, uint8_t *);
1430 		break;
1431 
1432 	case IEEE80211_FC0_SUBTYPE_DISASSOC:
1433 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
1434 			"[%6D] send station disassociate (reason %d)\n",
1435 			ni->ni_macaddr, ":", arg);
1436 		m = ieee80211_getmgtframe(&frm, sizeof(uint16_t));
1437 		if (m == NULL)
1438 			senderr(ENOMEM, is_tx_nobuf);
1439 		*(uint16_t *)frm = htole16(arg);	/* reason */
1440 		m->m_pkthdr.len = m->m_len = sizeof(uint16_t);
1441 
1442 		IEEE80211_NODE_STAT(ni, tx_disassoc);
1443 		IEEE80211_NODE_STAT_SET(ni, tx_disassoc_code, arg);
1444 		break;
1445 
1446 	default:
1447 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
1448 			"[%6D] invalid mgmt frame type %u\n",
1449 			ni->ni_macaddr, ":", type);
1450 		senderr(EINVAL, is_tx_unknownmgt);
1451 		/* NOTREACHED */
1452 	}
1453 	ret = ieee80211_mgmt_output(ic, ni, m, type, timer);
1454 	if (ret != 0) {
1455 bad:
1456 		ieee80211_free_node(ni);
1457 	}
1458 	return ret;
1459 #undef senderr
1460 }
1461 
1462 /*
1463  * Allocate a probe response frame and fillin the appropriate bits.
1464  */
1465 struct mbuf *
1466 ieee80211_probe_resp_alloc(struct ieee80211com *ic, struct ieee80211_node *ni)
1467 {
1468 	struct ieee80211_frame *wh;
1469 	struct mbuf *m;
1470 
1471 	m = _ieee80211_probe_resp_alloc(ic, ni);
1472 	if (m == NULL)
1473 		return NULL;
1474 
1475 	M_PREPEND(m, sizeof(struct ieee80211_frame), MB_DONTWAIT);
1476 	KASSERT(m != NULL, ("no space for 802.11 header?"));
1477 
1478 	wh = mtod(m, struct ieee80211_frame *);
1479 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT |
1480 		      IEEE80211_FC0_SUBTYPE_PROBE_RESP;
1481 	wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
1482 	*(uint16_t *)wh->i_dur = 0;
1483 	bzero(wh->i_addr1, sizeof(wh->i_addr1));
1484 	IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
1485 	IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
1486 	*(uint16_t *)wh->i_seq = 0;
1487 
1488 	return m;
1489 }
1490 
1491 /*
1492  * Allocate a beacon frame and fillin the appropriate bits.
1493  */
1494 struct mbuf *
1495 ieee80211_beacon_alloc(struct ieee80211com *ic, struct ieee80211_node *ni,
1496 	struct ieee80211_beacon_offsets *bo)
1497 {
1498 	struct ifnet *ifp = ic->ic_ifp;
1499 	struct ieee80211_frame *wh;
1500 	struct mbuf *m;
1501 	int pktlen;
1502 	uint8_t *frm, *efrm;
1503 	uint16_t capinfo;
1504 	const struct ieee80211_rateset *rs;
1505 
1506 	/*
1507 	 * beacon frame format
1508 	 *	[8] time stamp
1509 	 *	[2] beacon interval
1510 	 *	[2] cabability information
1511 	 *	[tlv] ssid
1512 	 *	[tlv] supported rates
1513 	 *	[3] parameter set (DS)
1514 	 *	[tlv] parameter set (IBSS/TIM)
1515 	 *	[tlv] extended rate phy (ERP)
1516 	 *	[tlv] extended supported rates
1517 	 *	[tlv] WME parameters
1518 	 *	[tlv] WPA/RSN parameters
1519 	 * XXX Vendor-specific OIDs (e.g. Atheros)
1520 	 * NB: we allocate the max space required for the TIM bitmap.
1521 	 */
1522 	KKASSERT(ic->ic_curmode != IEEE80211_MODE_AUTO);
1523 	rs = &ic->ic_sup_rates[ic->ic_curmode];
1524 	pktlen =   8					/* time stamp */
1525 		 + sizeof(uint16_t)			/* beacon interval */
1526 		 + sizeof(uint16_t)			/* capabilities */
1527 		 + 2 + ni->ni_esslen			/* ssid */
1528 	         + 2 + IEEE80211_RATE_SIZE		/* supported rates */
1529 	         + 2 + 1				/* DS parameters */
1530 		 + 2 + 4 + ic->ic_tim_len		/* DTIM/IBSSPARMS */
1531 		 + 2 + 1				/* ERP */
1532 	         + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE)
1533 		 + (ic->ic_caps & IEEE80211_C_WME ?	/* WME */
1534 			sizeof(struct ieee80211_wme_param) : 0)
1535 		 + (ic->ic_caps & IEEE80211_C_WPA ?	/* WPA 1+2 */
1536 			2*sizeof(struct ieee80211_ie_wpa) : 0)
1537 		 ;
1538 	m = ieee80211_getmgtframe(&frm, pktlen);
1539 	if (m == NULL) {
1540 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
1541 			"%s: cannot get buf; size %u\n", __func__, pktlen);
1542 		ic->ic_stats.is_tx_nobuf++;
1543 		return NULL;
1544 	}
1545 
1546 	memset(frm, 0, 8);	/* XXX timestamp is set by hardware/driver */
1547 	frm += 8;
1548 	*(uint16_t *)frm = htole16(ni->ni_intval);
1549 	frm += 2;
1550 	capinfo = getcapinfo(ic, ni->ni_chan);
1551 	bo->bo_caps = (uint16_t *)frm;
1552 	*(uint16_t *)frm = htole16(capinfo);
1553 	frm += 2;
1554 	*frm++ = IEEE80211_ELEMID_SSID;
1555 	if ((ic->ic_flags & IEEE80211_F_HIDESSID) == 0) {
1556 		*frm++ = ni->ni_esslen;
1557 		memcpy(frm, ni->ni_essid, ni->ni_esslen);
1558 		frm += ni->ni_esslen;
1559 	} else
1560 		*frm++ = 0;
1561 	frm = ieee80211_add_rates(frm, rs);
1562 	if (ic->ic_curmode != IEEE80211_MODE_FH) {
1563 		*frm++ = IEEE80211_ELEMID_DSPARMS;
1564 		*frm++ = 1;
1565 		*frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
1566 	}
1567 	bo->bo_tim = frm;
1568 	if (ic->ic_opmode == IEEE80211_M_IBSS) {
1569 		*frm++ = IEEE80211_ELEMID_IBSSPARMS;
1570 		*frm++ = 2;
1571 		*frm++ = 0; *frm++ = 0;		/* TODO: ATIM window */
1572 		bo->bo_tim_len = 0;
1573 	} else if (ic->ic_opmode == IEEE80211_M_HOSTAP) {
1574 		struct ieee80211_tim_ie *tie = (struct ieee80211_tim_ie *) frm;
1575 
1576 		tie->tim_ie = IEEE80211_ELEMID_TIM;
1577 		tie->tim_len = 4;	/* length */
1578 		tie->tim_count = 0;	/* DTIM count */
1579 		tie->tim_period = ic->ic_dtim_period;	/* DTIM period */
1580 		tie->tim_bitctl = 0;	/* bitmap control */
1581 		tie->tim_bitmap[0] = 0;	/* Partial Virtual Bitmap */
1582 		frm += sizeof(struct ieee80211_tim_ie);
1583 		bo->bo_tim_len = 1;
1584 	}
1585 	bo->bo_trailer = frm;
1586 	if (ic->ic_flags & IEEE80211_F_WME) {
1587 		bo->bo_wme = frm;
1588 		frm = ieee80211_add_wme_param(frm, &ic->ic_wme);
1589 		ic->ic_flags &= ~IEEE80211_F_WMEUPDATE;
1590 	}
1591 	if (ic->ic_flags & IEEE80211_F_WPA)
1592 		frm = ieee80211_add_wpa(frm, ic);
1593 	if (ic->ic_curmode == IEEE80211_MODE_11G) {
1594 		bo->bo_erp = frm;
1595 		frm = ieee80211_add_erp(frm, ic);
1596 	}
1597 	efrm = ieee80211_add_xrates(frm, rs);
1598 	bo->bo_trailer_len = efrm - bo->bo_trailer;
1599 	m->m_pkthdr.len = m->m_len = efrm - mtod(m, uint8_t *);
1600 	KKASSERT(m->m_len <= pktlen);
1601 
1602 	M_PREPEND(m, sizeof(struct ieee80211_frame), MB_DONTWAIT);
1603 	KASSERT(m != NULL, ("no space for 802.11 header?"));
1604 	wh = mtod(m, struct ieee80211_frame *);
1605 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT |
1606 	    IEEE80211_FC0_SUBTYPE_BEACON;
1607 	wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
1608 	*(uint16_t *)wh->i_dur = 0;
1609 	IEEE80211_ADDR_COPY(wh->i_addr1, ifp->if_broadcastaddr);
1610 	IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
1611 	IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
1612 	*(uint16_t *)wh->i_seq = 0;
1613 
1614 	return m;
1615 }
1616 
1617 /*
1618  * Update the dynamic parts of a beacon frame based on the current state.
1619  */
1620 int
1621 ieee80211_beacon_update(struct ieee80211com *ic, struct ieee80211_node *ni,
1622 	struct ieee80211_beacon_offsets *bo, struct mbuf *m, int mcast)
1623 {
1624 	int len_changed = 0;
1625 	uint16_t capinfo;
1626 
1627 	ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);
1628 
1629 	/* XXX faster to recalculate entirely or just changes? */
1630 	capinfo = getcapinfo(ic, ni->ni_chan);
1631 	*bo->bo_caps = htole16(capinfo);
1632 
1633 	if (ic->ic_flags & IEEE80211_F_WME) {
1634 		struct ieee80211_wme_state *wme = &ic->ic_wme;
1635 
1636 		/*
1637 		 * Check for agressive mode change.  When there is
1638 		 * significant high priority traffic in the BSS
1639 		 * throttle back BE traffic by using conservative
1640 		 * parameters.  Otherwise BE uses agressive params
1641 		 * to optimize performance of legacy/non-QoS traffic.
1642 		 */
1643 		if (wme->wme_flags & WME_F_AGGRMODE) {
1644 			if (wme->wme_hipri_traffic >
1645 			    wme->wme_hipri_switch_thresh) {
1646 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_WME,
1647 				    "%s: traffic %u, disable aggressive mode\n",
1648 				    __func__, wme->wme_hipri_traffic);
1649 				wme->wme_flags &= ~WME_F_AGGRMODE;
1650 				ieee80211_wme_updateparams(ic);
1651 				wme->wme_hipri_traffic =
1652 					wme->wme_hipri_switch_hysteresis;
1653 			} else
1654 				wme->wme_hipri_traffic = 0;
1655 		} else {
1656 			if (wme->wme_hipri_traffic <=
1657 			    wme->wme_hipri_switch_thresh) {
1658 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_WME,
1659 				    "%s: traffic %u, enable aggressive mode\n",
1660 				    __func__, wme->wme_hipri_traffic);
1661 				wme->wme_flags |= WME_F_AGGRMODE;
1662 				ieee80211_wme_updateparams(ic);
1663 				wme->wme_hipri_traffic = 0;
1664 			} else
1665 				wme->wme_hipri_traffic =
1666 					wme->wme_hipri_switch_hysteresis;
1667 		}
1668 		if (ic->ic_flags & IEEE80211_F_WMEUPDATE) {
1669 			(void) ieee80211_add_wme_param(bo->bo_wme, wme);
1670 			ic->ic_flags &= ~IEEE80211_F_WMEUPDATE;
1671 		}
1672 	}
1673 
1674 	if (ic->ic_opmode == IEEE80211_M_HOSTAP) {	/* NB: no IBSS support*/
1675 		struct ieee80211_tim_ie *tie =
1676 			(struct ieee80211_tim_ie *) bo->bo_tim;
1677 		if (ic->ic_flags & IEEE80211_F_TIMUPDATE) {
1678 			u_int timlen, timoff, i;
1679 			/*
1680 			 * ATIM/DTIM needs updating.  If it fits in the
1681 			 * current space allocated then just copy in the
1682 			 * new bits.  Otherwise we need to move any trailing
1683 			 * data to make room.  Note that we know there is
1684 			 * contiguous space because ieee80211_beacon_allocate
1685 			 * insures there is space in the mbuf to write a
1686 			 * maximal-size virtual bitmap (based on ic_max_aid).
1687 			 */
1688 			/*
1689 			 * Calculate the bitmap size and offset, copy any
1690 			 * trailer out of the way, and then copy in the
1691 			 * new bitmap and update the information element.
1692 			 * Note that the tim bitmap must contain at least
1693 			 * one byte and any offset must be even.
1694 			 */
1695 			if (ic->ic_ps_pending != 0) {
1696 				timoff = 128;		/* impossibly large */
1697 				for (i = 0; i < ic->ic_tim_len; i++)
1698 					if (ic->ic_tim_bitmap[i]) {
1699 						timoff = i &~ 1;
1700 						break;
1701 					}
1702 				KASSERT(timoff != 128, ("tim bitmap empty!"));
1703 				for (i = ic->ic_tim_len-1; i >= timoff; i--)
1704 					if (ic->ic_tim_bitmap[i])
1705 						break;
1706 				timlen = 1 + (i - timoff);
1707 			} else {
1708 				timoff = 0;
1709 				timlen = 1;
1710 			}
1711 			if (timlen != bo->bo_tim_len) {
1712 				/* copy up/down trailer */
1713 				int adjust = tie->tim_bitmap+timlen
1714 					   - bo->bo_trailer;
1715 				ovbcopy(bo->bo_trailer, bo->bo_trailer+adjust,
1716 					bo->bo_trailer_len);
1717 				bo->bo_trailer += adjust;
1718 				bo->bo_wme += adjust;
1719 				bo->bo_erp += adjust;
1720 				bo->bo_tim_len = timlen;
1721 
1722 				/* update information element */
1723 				tie->tim_len = 3 + timlen;
1724 				tie->tim_bitctl = timoff;
1725 				len_changed = 1;
1726 			}
1727 			memcpy(tie->tim_bitmap, ic->ic_tim_bitmap + timoff,
1728 				bo->bo_tim_len);
1729 
1730 			ic->ic_flags &= ~IEEE80211_F_TIMUPDATE;
1731 
1732 			IEEE80211_DPRINTF(ic, IEEE80211_MSG_POWER,
1733 				"%s: TIM updated, pending %u, off %u, len %u\n",
1734 				__func__, ic->ic_ps_pending, timoff, timlen);
1735 		}
1736 		/* count down DTIM period */
1737 		if (tie->tim_count == 0)
1738 			tie->tim_count = tie->tim_period - 1;
1739 		else
1740 			tie->tim_count--;
1741 		/* update state for buffered multicast frames on DTIM */
1742 		if (mcast && tie->tim_count == 0)
1743 			tie->tim_bitctl |= 1;
1744 		else
1745 			tie->tim_bitctl &= ~1;
1746 		if (ic->ic_flags_ext & IEEE80211_FEXT_ERPUPDATE) {
1747 			/*
1748 			 * ERP element needs updating.
1749 			 */
1750 			(void) ieee80211_add_erp(bo->bo_erp, ic);
1751 			ic->ic_flags_ext &= ~IEEE80211_FEXT_ERPUPDATE;
1752 		}
1753 	}
1754 
1755 	return len_changed;
1756 }
1757 
1758 /*
1759  * Save an outbound packet for a node in power-save sleep state.
1760  * The new packet is placed on the node's saved queue, and the TIM
1761  * is changed, if necessary.
1762  */
1763 void
1764 ieee80211_pwrsave(struct ieee80211com *ic, struct ieee80211_node *ni,
1765 		  struct mbuf *m)
1766 {
1767 	int qlen, age;
1768 
1769 	ASSERT_SERIALIZED(ic->ic_ifp->if_serializer);
1770 
1771 	if (IF_QFULL(&ni->ni_savedq)) {
1772 		IF_DROP(&ni->ni_savedq);
1773 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
1774 			"[%6D] pwr save q overflow, drops %d (size %d)\n",
1775 			ni->ni_macaddr, ":",
1776 			ni->ni_savedq.ifq_drops, IEEE80211_PS_MAX_QUEUE);
1777 #ifdef IEEE80211_DEBUG
1778 		if (ieee80211_msg_dumppkts(ic))
1779 			ieee80211_dump_pkt(mtod(m, caddr_t), m->m_len, -1, -1);
1780 #endif
1781 		m_freem(m);
1782 		return;
1783 	}
1784 	/*
1785 	 * Tag the frame with it's expiry time and insert
1786 	 * it in the queue.  The aging interval is 4 times
1787 	 * the listen interval specified by the station.
1788 	 * Frames that sit around too long are reclaimed
1789 	 * using this information.
1790 	 */
1791 	/* XXX handle overflow? */
1792 	age = ((ni->ni_intval * ic->ic_bintval) << 2) / 1024; /* TU -> secs */
1793 	_IEEE80211_NODE_SAVEQ_ENQUEUE(ni, m, qlen, age);
1794 
1795 	IEEE80211_DPRINTF(ic, IEEE80211_MSG_POWER,
1796 		"[%6D] save frame with age %d, %u now queued\n",
1797 		ni->ni_macaddr, ":", age, qlen);
1798 
1799 	if (qlen == 1)
1800 		ic->ic_set_tim(ni, 1);
1801 }
1802