xref: /netbsd-src/sys/net80211/ieee80211_output.c (revision 21e37cc72a480a47828990a439cde7ac9ffaf0c6)
1 /*	$NetBSD: ieee80211_output.c,v 1.13 2004/05/31 11:02:55 dyoung Exp $	*/
2 /*-
3  * Copyright (c) 2001 Atsushi Onoe
4  * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. The name of the author may not be used to endorse or promote products
16  *    derived from this software without specific prior written permission.
17  *
18  * Alternatively, this software may be distributed under the terms of the
19  * GNU General Public License ("GPL") version 2 as published by the Free
20  * Software Foundation.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
23  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
24  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
25  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
27  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
28  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
29  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
30  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
31  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <sys/cdefs.h>
35 #ifdef __FreeBSD__
36 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_output.c,v 1.10 2004/04/02 23:25:39 sam Exp $");
37 #else
38 __KERNEL_RCSID(0, "$NetBSD: ieee80211_output.c,v 1.13 2004/05/31 11:02:55 dyoung Exp $");
39 #endif
40 
41 #include "opt_inet.h"
42 
43 #ifdef __NetBSD__
44 #include "bpfilter.h"
45 #endif /* __NetBSD__ */
46 
47 #include <sys/param.h>
48 #include <sys/systm.h>
49 #include <sys/mbuf.h>
50 #include <sys/malloc.h>
51 #include <sys/kernel.h>
52 #include <sys/socket.h>
53 #include <sys/sockio.h>
54 #include <sys/endian.h>
55 #include <sys/errno.h>
56 #ifdef __FreeBSD__
57 #include <sys/bus.h>
58 #endif
59 #include <sys/proc.h>
60 #include <sys/sysctl.h>
61 
62 #ifdef __FreeBSD__
63 #include <machine/atomic.h>
64 #endif
65 
66 #include <net/if.h>
67 #include <net/if_dl.h>
68 #include <net/if_media.h>
69 #include <net/if_arp.h>
70 #ifdef __FreeBSD__
71 #include <net/ethernet.h>
72 #else
73 #include <net/if_ether.h>
74 #endif
75 #include <net/if_llc.h>
76 
77 #include <net80211/ieee80211_var.h>
78 #include <net80211/ieee80211_compat.h>
79 
80 #if NBPFILTER > 0
81 #include <net/bpf.h>
82 #endif
83 
84 #ifdef INET
85 #include <netinet/in.h>
86 #ifdef __FreeBSD__
87 #include <netinet/if_ether.h>
88 #else
89 #include <net/if_ether.h>
90 #endif
91 #endif
92 
93 /*
94  * Send a management frame to the specified node.  The node pointer
95  * must have a reference as the pointer will be passed to the driver
96  * and potentially held for a long time.  If the frame is successfully
97  * dispatched to the driver, then it is responsible for freeing the
98  * reference (and potentially free'ing up any associated storage).
99  */
100 static int
101 ieee80211_mgmt_output(struct ifnet *ifp, struct ieee80211_node *ni,
102     struct mbuf *m, int type)
103 {
104 	struct ieee80211com *ic = (void *)ifp;
105 	struct ieee80211_frame *wh;
106 
107 	IASSERT(ni != NULL, ("null node"));
108 	ni->ni_inact = 0;
109 
110 	/*
111 	 * Yech, hack alert!  We want to pass the node down to the
112 	 * driver's start routine.  If we don't do so then the start
113 	 * routine must immediately look it up again and that can
114 	 * cause a lock order reversal if, for example, this frame
115 	 * is being sent because the station is being timedout and
116 	 * the frame being sent is a DEAUTH message.  We could stick
117 	 * this in an m_tag and tack that on to the mbuf.  However
118 	 * that's rather expensive to do for every frame so instead
119 	 * we stuff it in the rcvif field since outbound frames do
120 	 * not (presently) use this.
121 	 */
122 	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
123 	if (m == NULL)
124 		return ENOMEM;
125 #ifdef __FreeBSD__
126 	KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
127 #endif
128 	m->m_pkthdr.rcvif = (void *)ni;
129 
130 	wh = mtod(m, struct ieee80211_frame *);
131 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT | type;
132 	wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
133 	*(u_int16_t *)&wh->i_dur[0] = 0;
134 	*(u_int16_t *)&wh->i_seq[0] =
135 	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
136 	ni->ni_txseq++;
137 	IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_macaddr);
138 	IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
139 	IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
140 
141 	if ((m->m_flags & M_LINK0) != 0 && ni->ni_challenge != NULL) {
142 		m->m_flags &= ~M_LINK0;
143 		IEEE80211_DPRINTF(("%s: encrypting frame for %s\n", __func__,
144 		    ether_sprintf(wh->i_addr1)));
145 		wh->i_fc[1] |= IEEE80211_FC1_WEP;
146 	}
147 
148 	if (ifp->if_flags & IFF_DEBUG) {
149 		/* avoid to print too many frames */
150 		if (ic->ic_opmode == IEEE80211_M_IBSS ||
151 #ifdef IEEE80211_DEBUG
152 		    ieee80211_debug > 1 ||
153 #endif
154 		    (type & IEEE80211_FC0_SUBTYPE_MASK) !=
155 		    IEEE80211_FC0_SUBTYPE_PROBE_RESP)
156 			if_printf(ifp, "sending %s to %s on channel %u\n",
157 			    ieee80211_mgt_subtype_name[
158 			    (type & IEEE80211_FC0_SUBTYPE_MASK)
159 			    >> IEEE80211_FC0_SUBTYPE_SHIFT],
160 			    ether_sprintf(ni->ni_macaddr),
161 			    ieee80211_chan2ieee(ic, ni->ni_chan));
162 	}
163 
164 	IF_ENQUEUE(&ic->ic_mgtq, m);
165 	ifp->if_timer = 1;
166 	(*ifp->if_start)(ifp);
167 	return 0;
168 }
169 
170 /*
171  * Encapsulate an outbound data frame.  The mbuf chain is updated and
172  * a reference to the destination node is returned.  If an error is
173  * encountered NULL is returned and the node reference will also be NULL.
174  *
175  * NB: The caller is responsible for free'ing a returned node reference.
176  *     The convention is ic_bss is not reference counted; the caller must
177  *     maintain that.
178  */
179 struct mbuf *
180 ieee80211_encap(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node **pni)
181 {
182 	struct ieee80211com *ic = (void *)ifp;
183 	struct ether_header eh;
184 	struct ieee80211_frame *wh;
185 	struct ieee80211_node *ni = NULL;
186 	struct llc *llc;
187 
188 	if (m->m_len < sizeof(struct ether_header)) {
189 		m = m_pullup(m, sizeof(struct ether_header));
190 		if (m == NULL) {
191 			ic->ic_stats.is_tx_nombuf++;
192 			goto bad;
193 		}
194 	}
195 	memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
196 
197 	ni = ieee80211_find_txnode(ic, eh.ether_dhost);
198 	if (ni == NULL) {
199 		IEEE80211_DPRINTF(("%s: no node for dst %s, discard frame\n",
200 			__func__, ether_sprintf(eh.ether_dhost)));
201 		ic->ic_stats.is_tx_nonode++;
202 		goto bad;
203 	}
204 	ni->ni_inact = 0;
205 
206 	m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
207 	llc = mtod(m, struct llc *);
208 	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
209 	llc->llc_control = LLC_UI;
210 	llc->llc_snap.org_code[0] = 0;
211 	llc->llc_snap.org_code[1] = 0;
212 	llc->llc_snap.org_code[2] = 0;
213 	llc->llc_snap.ether_type = eh.ether_type;
214 	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
215 	if (m == NULL) {
216 		ic->ic_stats.is_tx_nombuf++;
217 		goto bad;
218 	}
219 	wh = mtod(m, struct ieee80211_frame *);
220 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
221 	*(u_int16_t *)&wh->i_dur[0] = 0;
222 	*(u_int16_t *)&wh->i_seq[0] =
223 	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
224 	ni->ni_txseq++;
225 	switch (ic->ic_opmode) {
226 	case IEEE80211_M_STA:
227 		wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
228 		IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
229 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
230 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
231 		break;
232 	case IEEE80211_M_IBSS:
233 	case IEEE80211_M_AHDEMO:
234 		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
235 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
236 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
237 		IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
238 		break;
239 	case IEEE80211_M_HOSTAP:
240 		wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
241 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
242 		IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
243 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
244 		break;
245 	case IEEE80211_M_MONITOR:
246 		goto bad;
247 	}
248 	if (ic->ic_flags & IEEE80211_F_WEPON)
249 		wh->i_fc[1] |= IEEE80211_FC1_WEP;
250 	*pni = ni;
251 	return m;
252 bad:
253 	if (m != NULL)
254 		m_freem(m);
255 	if (ni && ni != ic->ic_bss)
256 		ieee80211_free_node(ic, ni);
257 	*pni = NULL;
258 	return NULL;
259 }
260 
261 /*
262  * Add a supported rates element id to a frame.
263  */
264 u_int8_t *
265 ieee80211_add_rates(u_int8_t *frm, const struct ieee80211_rateset *rs)
266 {
267 	int nrates;
268 
269 	*frm++ = IEEE80211_ELEMID_RATES;
270 	nrates = rs->rs_nrates;
271 	if (nrates > IEEE80211_RATE_SIZE)
272 		nrates = IEEE80211_RATE_SIZE;
273 	*frm++ = nrates;
274 	memcpy(frm, rs->rs_rates, nrates);
275 	return frm + nrates;
276 }
277 
278 /*
279  * Add an extended supported rates element id to a frame.
280  */
281 u_int8_t *
282 ieee80211_add_xrates(u_int8_t *frm, const struct ieee80211_rateset *rs)
283 {
284 	/*
285 	 * Add an extended supported rates element if operating in 11g mode.
286 	 */
287 	if (rs->rs_nrates > IEEE80211_RATE_SIZE) {
288 		int nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
289 		*frm++ = IEEE80211_ELEMID_XRATES;
290 		*frm++ = nrates;
291 		memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
292 		frm += nrates;
293 	}
294 	return frm;
295 }
296 
297 /*
298  * Add an ssid elemet to a frame.
299  */
300 static u_int8_t *
301 ieee80211_add_ssid(u_int8_t *frm, const u_int8_t *ssid, u_int len)
302 {
303 	*frm++ = IEEE80211_ELEMID_SSID;
304 	*frm++ = len;
305 	memcpy(frm, ssid, len);
306 	return frm + len;
307 }
308 
309 static struct mbuf *
310 ieee80211_getmbuf(int flags, int type, u_int pktlen)
311 {
312 	struct mbuf *m;
313 
314 	IASSERT(pktlen <= MCLBYTES, ("802.11 packet too large: %u", pktlen));
315 #ifdef __FreeBSD__
316 	if (pktlen <= MHLEN)
317 		MGETHDR(m, flags, type);
318 	else
319 		m = m_getcl(flags, type, M_PKTHDR);
320 #else
321 	MGETHDR(m, flags, type);
322 	if (m != NULL && pktlen > MHLEN)
323 		MCLGET(m, flags);
324 #endif
325 	return m;
326 }
327 
328 /*
329  * Send a management frame.  The node is for the destination (or ic_bss
330  * when in station mode).  Nodes other than ic_bss have their reference
331  * count bumped to reflect our use for an indeterminant time.
332  */
333 int
334 ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
335 	int type, int arg)
336 {
337 #define	senderr(_x, _v)	do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
338 	struct ifnet *ifp = &ic->ic_if;
339 	struct mbuf *m;
340 	u_int8_t *frm;
341 	enum ieee80211_phymode mode;
342 	u_int16_t capinfo;
343 	int has_challenge, is_shared_key, ret, timer;
344 
345 	IASSERT(ni != NULL, ("null node"));
346 
347 	/*
348 	 * Hold a reference on the node so it doesn't go away until after
349 	 * the xmit is complete all the way in the driver.  On error we
350 	 * will remove our reference.
351 	 */
352 	if (ni != ic->ic_bss)
353 		ieee80211_ref_node(ni);
354 	timer = 0;
355 	switch (type) {
356 	case IEEE80211_FC0_SUBTYPE_PROBE_REQ:
357 		/*
358 		 * prreq frame format
359 		 *	[tlv] ssid
360 		 *	[tlv] supported rates
361 		 *	[tlv] extended supported rates
362 		 */
363 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
364 			 2 + ic->ic_des_esslen
365 		       + 2 + IEEE80211_RATE_SIZE
366 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
367 		if (m == NULL)
368 			senderr(ENOMEM, is_tx_nombuf);
369 		m->m_data += sizeof(struct ieee80211_frame);
370 		frm = mtod(m, u_int8_t *);
371 		frm = ieee80211_add_ssid(frm, ic->ic_des_essid, ic->ic_des_esslen);
372 		mode = ieee80211_chan2mode(ic, ni->ni_chan);
373 		frm = ieee80211_add_rates(frm, &ic->ic_sup_rates[mode]);
374 		frm = ieee80211_add_xrates(frm, &ic->ic_sup_rates[mode]);
375 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
376 
377 		timer = IEEE80211_TRANS_WAIT;
378 		break;
379 
380 	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
381 		/*
382 		 * probe response frame format
383 		 *	[8] time stamp
384 		 *	[2] beacon interval
385 		 *	[2] cabability information
386 		 *	[tlv] ssid
387 		 *	[tlv] supported rates
388 		 *	[tlv] parameter set (FH/DS)
389 		 *	[tlv] parameter set (IBSS)
390 		 *	[tlv] extended supported rates
391 		 */
392 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
393 			 8 + 2 + 2 + 2
394 		       + 2 + ni->ni_esslen
395 		       + 2 + IEEE80211_RATE_SIZE
396 		       + (ic->ic_phytype == IEEE80211_T_FH ? 7 : 3)
397 		       + 6
398 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
399 		if (m == NULL)
400 			senderr(ENOMEM, is_tx_nombuf);
401 		m->m_data += sizeof(struct ieee80211_frame);
402 		frm = mtod(m, u_int8_t *);
403 
404 		memset(frm, 0, 8);	/* timestamp should be filled later */
405 		frm += 8;
406 		*(u_int16_t *)frm = htole16(ic->ic_bss->ni_intval);
407 		frm += 2;
408 		if (ic->ic_opmode == IEEE80211_M_IBSS)
409 			capinfo = IEEE80211_CAPINFO_IBSS;
410 		else
411 			capinfo = IEEE80211_CAPINFO_ESS;
412 		if (ic->ic_flags & IEEE80211_F_WEPON)
413 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
414 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
415 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
416 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
417 		*(u_int16_t *)frm = htole16(capinfo);
418 		frm += 2;
419 
420 		frm = ieee80211_add_ssid(frm, ic->ic_bss->ni_essid,
421 				ic->ic_bss->ni_esslen);
422 		frm = ieee80211_add_rates(frm, &ic->ic_bss->ni_rates);
423 
424 		if (ic->ic_phytype == IEEE80211_T_FH) {
425                         *frm++ = IEEE80211_ELEMID_FHPARMS;
426                         *frm++ = 5;
427                         *frm++ = ni->ni_fhdwell & 0x00ff;
428                         *frm++ = (ni->ni_fhdwell >> 8) & 0x00ff;
429                         *frm++ = IEEE80211_FH_CHANSET(
430 			    ieee80211_chan2ieee(ic, ni->ni_chan));
431                         *frm++ = IEEE80211_FH_CHANPAT(
432 			    ieee80211_chan2ieee(ic, ni->ni_chan));
433                         *frm++ = ni->ni_fhindex;
434 		} else {
435 			*frm++ = IEEE80211_ELEMID_DSPARMS;
436 			*frm++ = 1;
437 			*frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
438 		}
439 
440 		if (ic->ic_opmode == IEEE80211_M_IBSS) {
441 			*frm++ = IEEE80211_ELEMID_IBSSPARMS;
442 			*frm++ = 2;
443 			*frm++ = 0; *frm++ = 0;		/* TODO: ATIM window */
444 		} else {	/* IEEE80211_M_HOSTAP */
445 			/* TODO: TIM */
446 			*frm++ = IEEE80211_ELEMID_TIM;
447 			*frm++ = 4;	/* length */
448 			*frm++ = 0;	/* DTIM count */
449 			*frm++ = 1;	/* DTIM period */
450 			*frm++ = 0;	/* bitmap control */
451 			*frm++ = 0;	/* Partial Virtual Bitmap (variable length) */
452 		}
453 		frm = ieee80211_add_xrates(frm, &ic->ic_bss->ni_rates);
454 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
455 		break;
456 
457 	case IEEE80211_FC0_SUBTYPE_AUTH:
458 		MGETHDR(m, M_DONTWAIT, MT_DATA);
459 		if (m == NULL)
460 			senderr(ENOMEM, is_tx_nombuf);
461 
462 		has_challenge = ((arg == IEEE80211_AUTH_SHARED_CHALLENGE ||
463 		    arg == IEEE80211_AUTH_SHARED_RESPONSE) &&
464 		    ni->ni_challenge != NULL);
465 
466 		is_shared_key = has_challenge || (ni->ni_challenge != NULL &&
467 		    arg == IEEE80211_AUTH_SHARED_PASS);
468 
469 		if (has_challenge) {
470 			MH_ALIGN(m, 2 * 3 + 2 + IEEE80211_CHALLENGE_LEN);
471 			m->m_pkthdr.len = m->m_len =
472 			    2 * 3 + 2 + IEEE80211_CHALLENGE_LEN;
473 		} else {
474 			MH_ALIGN(m, 2 * 3);
475 			m->m_pkthdr.len = m->m_len = 2 * 3;
476 		}
477 		frm = mtod(m, u_int8_t *);
478 		((u_int16_t *)frm)[0] =
479 		    (is_shared_key) ? htole16(IEEE80211_AUTH_ALG_SHARED)
480 		                    : htole16(IEEE80211_AUTH_ALG_OPEN);
481 		((u_int16_t *)frm)[1] = htole16(arg);	/* sequence number */
482 		((u_int16_t *)frm)[2] = 0;		/* status */
483 
484 		if (has_challenge) {
485 			((u_int16_t *)frm)[3] =
486 			    htole16((IEEE80211_CHALLENGE_LEN << 8) |
487 			    IEEE80211_ELEMID_CHALLENGE);
488 			memcpy(&((u_int16_t *)frm)[4], ni->ni_challenge,
489 			    IEEE80211_CHALLENGE_LEN);
490 			if (arg == IEEE80211_AUTH_SHARED_RESPONSE) {
491 				IEEE80211_DPRINTF((
492 				    "%s: request encrypt frame\n", __func__));
493 				m->m_flags |= M_LINK0; /* WEP-encrypt, please */
494 			}
495 		}
496 		if (ic->ic_opmode == IEEE80211_M_STA)
497 			timer = IEEE80211_TRANS_WAIT;
498 		break;
499 
500 	case IEEE80211_FC0_SUBTYPE_DEAUTH:
501 		if (ifp->if_flags & IFF_DEBUG)
502 			if_printf(ifp, "station %s deauthenticate (reason %d)\n",
503 			    ether_sprintf(ni->ni_macaddr), arg);
504 		MGETHDR(m, M_DONTWAIT, MT_DATA);
505 		if (m == NULL)
506 			senderr(ENOMEM, is_tx_nombuf);
507 		MH_ALIGN(m, 2);
508 		m->m_pkthdr.len = m->m_len = 2;
509 		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
510 		break;
511 
512 	case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
513 	case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
514 		/*
515 		 * asreq frame format
516 		 *	[2] capability information
517 		 *	[2] listen interval
518 		 *	[6*] current AP address (reassoc only)
519 		 *	[tlv] ssid
520 		 *	[tlv] supported rates
521 		 *	[tlv] extended supported rates
522 		 */
523 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
524 			 sizeof(capinfo)
525 		       + sizeof(u_int16_t)
526 		       + IEEE80211_ADDR_LEN
527 		       + 2 + ni->ni_esslen
528 		       + 2 + IEEE80211_RATE_SIZE
529 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
530 		if (m == NULL)
531 			senderr(ENOMEM, is_tx_nombuf);
532 		m->m_data += sizeof(struct ieee80211_frame);
533 		frm = mtod(m, u_int8_t *);
534 
535 		capinfo = 0;
536 		if (ic->ic_opmode == IEEE80211_M_IBSS)
537 			capinfo |= IEEE80211_CAPINFO_IBSS;
538 		else		/* IEEE80211_M_STA */
539 			capinfo |= IEEE80211_CAPINFO_ESS;
540 		if (ic->ic_flags & IEEE80211_F_WEPON)
541 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
542 		/*
543 		 * NB: Some 11a AP's reject the request when
544 		 *     short premable is set.
545 		 */
546 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
547 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
548 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
549 		if (ic->ic_flags & IEEE80211_F_SHSLOT)
550 			capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
551 		*(u_int16_t *)frm = htole16(capinfo);
552 		frm += 2;
553 
554 		*(u_int16_t *)frm = htole16(ic->ic_lintval);
555 		frm += 2;
556 
557 		if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
558 			IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
559 			frm += IEEE80211_ADDR_LEN;
560 		}
561 
562 		frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
563 		frm = ieee80211_add_rates(frm, &ni->ni_rates);
564 		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
565 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
566 
567 		timer = IEEE80211_TRANS_WAIT;
568 		break;
569 
570 	case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
571 	case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
572 		/*
573 		 * asreq frame format
574 		 *	[2] capability information
575 		 *	[2] status
576 		 *	[2] association ID
577 		 *	[tlv] supported rates
578 		 *	[tlv] extended supported rates
579 		 */
580 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
581 			 sizeof(capinfo)
582 		       + sizeof(u_int16_t)
583 		       + sizeof(u_int16_t)
584 		       + 2 + IEEE80211_RATE_SIZE
585 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
586 		if (m == NULL)
587 			senderr(ENOMEM, is_tx_nombuf);
588 		m->m_data += sizeof(struct ieee80211_frame);
589 		frm = mtod(m, u_int8_t *);
590 
591 		capinfo = IEEE80211_CAPINFO_ESS;
592 		if (ic->ic_flags & IEEE80211_F_WEPON)
593 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
594 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
595 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
596 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
597 		*(u_int16_t *)frm = htole16(capinfo);
598 		frm += 2;
599 
600 		*(u_int16_t *)frm = htole16(arg);	/* status */
601 		frm += 2;
602 
603 		if (arg == IEEE80211_STATUS_SUCCESS)
604 			*(u_int16_t *)frm = htole16(ni->ni_associd);
605 		frm += 2;
606 
607 		frm = ieee80211_add_rates(frm, &ni->ni_rates);
608 		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
609 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
610 		break;
611 
612 	case IEEE80211_FC0_SUBTYPE_DISASSOC:
613 		if (ifp->if_flags & IFF_DEBUG)
614 			if_printf(ifp, "station %s disassociate (reason %d)\n",
615 			    ether_sprintf(ni->ni_macaddr), arg);
616 		MGETHDR(m, M_DONTWAIT, MT_DATA);
617 		if (m == NULL)
618 			senderr(ENOMEM, is_tx_nombuf);
619 		MH_ALIGN(m, 2);
620 		m->m_pkthdr.len = m->m_len = 2;
621 		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
622 		break;
623 
624 	default:
625 		IEEE80211_DPRINTF(("%s: invalid mgmt frame type %u\n",
626 			__func__, type));
627 		senderr(EINVAL, is_tx_unknownmgt);
628 		/* NOTREACHED */
629 	}
630 
631 	ret = ieee80211_mgmt_output(ifp, ni, m, type);
632 	if (ret == 0) {
633 		if (timer)
634 			ic->ic_mgt_timer = timer;
635 	} else {
636 bad:
637 		if (ni != ic->ic_bss)		/* remove ref we added */
638 			ieee80211_free_node(ic, ni);
639 	}
640 	return ret;
641 #undef senderr
642 }
643 
644 void
645 ieee80211_pwrsave(struct ieee80211com *ic, struct ieee80211_node *ni,
646 		  struct mbuf *m)
647 {
648 	/* Store the new packet on our queue, changing the TIM if necessary */
649 
650 	if (IF_IS_EMPTY(&ni->ni_savedq)) {
651 		ic->ic_set_tim(ic, ni->ni_associd, 1);
652 	}
653 	if (ni->ni_savedq.ifq_len >= IEEE80211_PS_MAX_QUEUE) {
654 		IF_DROP(&ni->ni_savedq);
655 		m_freem(m);
656 		if (ic->ic_if.if_flags & IFF_DEBUG)
657 			printf("%s: station %s power save queue overflow"
658 			       " of size %d drops %d\n",
659 			       ic->ic_if.if_xname,
660 			       ether_sprintf(ni->ni_macaddr),
661 			       IEEE80211_PS_MAX_QUEUE,
662 			       ni->ni_savedq.ifq_drops);
663 	} else {
664 		/* Similar to ieee80211_mgmt_output, store the node in
665 		 * the rcvif field.
666 		 */
667 		IF_ENQUEUE(&ni->ni_savedq, m);
668 		m->m_pkthdr.rcvif = (void *)ni;
669 	}
670 }
671 
672