ieee80211_output.c revision 121180
1/*-
2 * Copyright (c) 2001 Atsushi Onoe
3 * Copyright (c) 2002, 2003 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
33#include <sys/cdefs.h>
34__FBSDID("$FreeBSD: head/sys/net80211/ieee80211_output.c 121180 2003-10-17 23:15:30Z sam $");
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/malloc.h>
42#include <sys/kernel.h>
43#include <sys/socket.h>
44#include <sys/sockio.h>
45#include <sys/endian.h>
46#include <sys/errno.h>
47#include <sys/bus.h>
48#include <sys/proc.h>
49#include <sys/sysctl.h>
50
51#include <machine/atomic.h>
52
53#include <net/if.h>
54#include <net/if_dl.h>
55#include <net/if_media.h>
56#include <net/if_arp.h>
57#include <net/ethernet.h>
58#include <net/if_llc.h>
59
60#include <net80211/ieee80211_var.h>
61
62#include <net/bpf.h>
63
64#ifdef INET
65#include <netinet/in.h>
66#include <netinet/if_ether.h>
67#endif
68
69/*
70 * Send a management frame to the specified node.  The node pointer
71 * must have a reference as the pointer will be passed to the driver
72 * and potentially held for a long time.  If the frame is successfully
73 * dispatched to the driver, then it is responsible for freeing the
74 * reference (and potentially free'ing up any associated storage).
75 */
76static int
77ieee80211_mgmt_output(struct ifnet *ifp, struct ieee80211_node *ni,
78    struct mbuf *m, int type)
79{
80	struct ieee80211com *ic = (void *)ifp;
81	struct ieee80211_frame *wh;
82
83	KASSERT(ni != NULL, ("null node"));
84	ni->ni_inact = 0;
85
86	/*
87	 * Yech, hack alert!  We want to pass the node down to the
88	 * driver's start routine.  If we don't do so then the start
89	 * routine must immediately look it up again and that can
90	 * cause a lock order reversal if, for example, this frame
91	 * is being sent because the station is being timedout and
92	 * the frame being sent is a DEAUTH message.  We could stick
93	 * this in an m_tag and tack that on to the mbuf.  However
94	 * that's rather expensive to do for every frame so instead
95	 * we stuff it in the rcvif field since outbound frames do
96	 * not (presently) use this.
97	 */
98	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
99	if (m == NULL)
100		return ENOMEM;
101	KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
102	m->m_pkthdr.rcvif = (void *)ni;
103
104	wh = mtod(m, struct ieee80211_frame *);
105	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT | type;
106	wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
107	*(u_int16_t *)wh->i_dur = 0;
108	*(u_int16_t *)wh->i_seq =
109	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
110	ni->ni_txseq++;
111	IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_macaddr);
112	IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
113	IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
114
115	if (ifp->if_flags & IFF_DEBUG) {
116		/* avoid to print too many frames */
117		if (ic->ic_opmode == IEEE80211_M_IBSS ||
118#ifdef IEEE80211_DEBUG
119		    ieee80211_debug > 1 ||
120#endif
121		    (type & IEEE80211_FC0_SUBTYPE_MASK) !=
122		    IEEE80211_FC0_SUBTYPE_PROBE_RESP)
123			if_printf(ifp, "sending %s to %s on channel %u\n",
124			    ieee80211_mgt_subtype_name[
125			    (type & IEEE80211_FC0_SUBTYPE_MASK)
126			    >> IEEE80211_FC0_SUBTYPE_SHIFT],
127			    ether_sprintf(ni->ni_macaddr),
128			    ieee80211_chan2ieee(ic, ni->ni_chan));
129	}
130
131	IF_ENQUEUE(&ic->ic_mgtq, m);
132	ifp->if_timer = 1;
133	(*ifp->if_start)(ifp);
134	return 0;
135}
136
137/*
138 * Encapsulate an outbound data frame.  The mbuf chain is updated and
139 * a reference to the destination node is returned.  If an error is
140 * encountered NULL is returned and the node reference will also be NULL.
141 *
142 * NB: The caller is responsible for free'ing a returned node reference.
143 *     The convention is ic_bss is not reference counted; the caller must
144 *     maintain that.
145 */
146struct mbuf *
147ieee80211_encap(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node **pni)
148{
149	struct ieee80211com *ic = (void *)ifp;
150	struct ether_header eh;
151	struct ieee80211_frame *wh;
152	struct ieee80211_node *ni = NULL;
153	struct llc *llc;
154
155	if (m->m_len < sizeof(struct ether_header)) {
156		m = m_pullup(m, sizeof(struct ether_header));
157		if (m == NULL) {
158			ic->ic_stats.is_tx_nombuf++;
159			goto bad;
160		}
161	}
162	memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
163
164	if (ic->ic_opmode != IEEE80211_M_STA) {
165		ni = ieee80211_find_node(ic, eh.ether_dhost);
166		if (ni == NULL) {
167			/*
168			 * When not in station mode the destination
169			 * address should always be in the node table
170			 * if the device sends management frames to us;
171			 * unless this is a multicast/broadcast frame.
172			 * For devices that don't send management frames
173			 * to the host we have to cheat; use the bss
174			 * node instead; the card will/should clobber
175			 * the bssid address as necessary.
176			 *
177			 * XXX this handles AHDEMO because all devices
178			 *     that support it don't send mgmt frames;
179			 *     but it might be better to test explicitly
180			 */
181			if (!IEEE80211_IS_MULTICAST(eh.ether_dhost) &&
182			    (ic->ic_caps & IEEE80211_C_RCVMGT)) {
183				IEEE80211_DPRINTF(("%s: no node for dst %s, "
184					"discard frame\n", __func__,
185					ether_sprintf(eh.ether_dhost)));
186				ic->ic_stats.is_tx_nonode++;
187				goto bad;
188			}
189			ni = ic->ic_bss;
190		}
191	} else
192		ni = ic->ic_bss;
193	ni->ni_inact = 0;
194
195	m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
196	llc = mtod(m, struct llc *);
197	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
198	llc->llc_control = LLC_UI;
199	llc->llc_snap.org_code[0] = 0;
200	llc->llc_snap.org_code[1] = 0;
201	llc->llc_snap.org_code[2] = 0;
202	llc->llc_snap.ether_type = eh.ether_type;
203	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
204	if (m == NULL) {
205		ic->ic_stats.is_tx_nombuf++;
206		goto bad;
207	}
208	wh = mtod(m, struct ieee80211_frame *);
209	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
210	*(u_int16_t *)wh->i_dur = 0;
211	*(u_int16_t *)wh->i_seq =
212	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
213	ni->ni_txseq++;
214	switch (ic->ic_opmode) {
215	case IEEE80211_M_STA:
216		wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
217		IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
218		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
219		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
220		break;
221	case IEEE80211_M_IBSS:
222	case IEEE80211_M_AHDEMO:
223		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
224		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
225		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
226		IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
227		break;
228	case IEEE80211_M_HOSTAP:
229		wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
230		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
231		IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
232		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
233		break;
234	case IEEE80211_M_MONITOR:
235		goto bad;
236	}
237	*pni = ni;
238	return m;
239bad:
240	if (m != NULL)
241		m_freem(m);
242	if (ni && ni != ic->ic_bss)
243		ieee80211_free_node(ic, ni);
244	*pni = NULL;
245	return NULL;
246}
247
248/*
249 * Add a supported rates element id to a frame.
250 */
251u_int8_t *
252ieee80211_add_rates(u_int8_t *frm, const struct ieee80211_rateset *rs)
253{
254	int nrates;
255
256	*frm++ = IEEE80211_ELEMID_RATES;
257	nrates = rs->rs_nrates;
258	if (nrates > IEEE80211_RATE_SIZE)
259		nrates = IEEE80211_RATE_SIZE;
260	*frm++ = nrates;
261	memcpy(frm, rs->rs_rates, nrates);
262	return frm + nrates;
263}
264
265/*
266 * Add an extended supported rates element id to a frame.
267 */
268u_int8_t *
269ieee80211_add_xrates(u_int8_t *frm, const struct ieee80211_rateset *rs)
270{
271	/*
272	 * Add an extended supported rates element if operating in 11g mode.
273	 */
274	if (rs->rs_nrates > IEEE80211_RATE_SIZE) {
275		int nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
276		*frm++ = IEEE80211_ELEMID_XRATES;
277		*frm++ = nrates;
278		memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
279		frm += nrates;
280	}
281	return frm;
282}
283
284/*
285 * Add an ssid elemet to a frame.
286 */
287static u_int8_t *
288ieee80211_add_ssid(u_int8_t *frm, const u_int8_t *ssid, u_int len)
289{
290	*frm++ = IEEE80211_ELEMID_SSID;
291	*frm++ = len;
292	memcpy(frm, ssid, len);
293	return frm + len;
294}
295
296static struct mbuf *
297ieee80211_getmbuf(int flags, int type, u_int pktlen)
298{
299	struct mbuf *m;
300
301	KASSERT(pktlen <= MCLBYTES, ("802.11 packet too large: %u", pktlen));
302	if (pktlen <= MHLEN)
303		MGETHDR(m, flags, type);
304	else
305		m = m_getcl(flags, type, M_PKTHDR);
306	return m;
307}
308
309/*
310 * Send a management frame.  The node is for the destination (or ic_bss
311 * when in station mode).  Nodes other than ic_bss have their reference
312 * count bumped to reflect our use for an indeterminant time.
313 */
314int
315ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
316	int type, int arg)
317{
318#define	senderr(_x, _v)	do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
319	struct ifnet *ifp = &ic->ic_if;
320	struct mbuf *m;
321	u_int8_t *frm;
322	enum ieee80211_phymode mode;
323	u_int16_t capinfo;
324	int ret, timer;
325
326	KASSERT(ni != NULL, ("null node"));
327
328	/*
329	 * Hold a reference on the node so it doesn't go away until after
330	 * the xmit is complete all the way in the driver.  On error we
331	 * will remove our reference.
332	 */
333	if (ni != ic->ic_bss)
334		ieee80211_ref_node(ni);
335	timer = 0;
336	switch (type) {
337	case IEEE80211_FC0_SUBTYPE_PROBE_REQ:
338		/*
339		 * prreq frame format
340		 *	[tlv] ssid
341		 *	[tlv] supported rates
342		 *	[tlv] extended supported rates
343		 */
344		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
345			 2 + ic->ic_des_esslen
346		       + 2 + IEEE80211_RATE_SIZE
347		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
348		if (m == NULL)
349			senderr(ENOMEM, is_tx_nombuf);
350		m->m_data += sizeof(struct ieee80211_frame);
351		frm = mtod(m, u_int8_t *);
352		frm = ieee80211_add_ssid(frm, ic->ic_des_essid, ic->ic_des_esslen);
353		mode = ieee80211_chan2mode(ic, ni->ni_chan);
354		frm = ieee80211_add_rates(frm, &ic->ic_sup_rates[mode]);
355		frm = ieee80211_add_xrates(frm, &ic->ic_sup_rates[mode]);
356		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
357
358		timer = IEEE80211_TRANS_WAIT;
359		break;
360
361	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
362		/*
363		 * probe response frame format
364		 *	[8] time stamp
365		 *	[2] beacon interval
366		 *	[2] cabability information
367		 *	[tlv] ssid
368		 *	[tlv] supported rates
369		 *	[tlv] parameter set (FH/DS)
370		 *	[tlv] parameter set (IBSS)
371		 *	[tlv] extended supported rates
372		 */
373		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
374			 8 + 2 + 2 + 2
375		       + 2 + ni->ni_esslen
376		       + 2 + IEEE80211_RATE_SIZE
377		       + (ic->ic_phytype == IEEE80211_T_FH ? 7 : 3)
378		       + 6
379		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
380		if (m == NULL)
381			senderr(ENOMEM, is_tx_nombuf);
382		m->m_data += sizeof(struct ieee80211_frame);
383		frm = mtod(m, u_int8_t *);
384
385		memset(frm, 0, 8);	/* timestamp should be filled later */
386		frm += 8;
387		*(u_int16_t *)frm = htole16(ic->ic_bss->ni_intval);
388		frm += 2;
389		if (ic->ic_opmode == IEEE80211_M_IBSS)
390			capinfo = IEEE80211_CAPINFO_IBSS;
391		else
392			capinfo = IEEE80211_CAPINFO_ESS;
393		if (ic->ic_flags & IEEE80211_F_WEPON)
394			capinfo |= IEEE80211_CAPINFO_PRIVACY;
395		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
396		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
397			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
398		*(u_int16_t *)frm = htole16(capinfo);
399		frm += 2;
400
401		frm = ieee80211_add_ssid(frm, ic->ic_bss->ni_essid,
402				ic->ic_bss->ni_esslen);
403		frm = ieee80211_add_rates(frm, &ic->ic_bss->ni_rates);
404
405		if (ic->ic_phytype == IEEE80211_T_FH) {
406                        *frm++ = IEEE80211_ELEMID_FHPARMS;
407                        *frm++ = 5;
408                        *frm++ = ni->ni_fhdwell & 0x00ff;
409                        *frm++ = (ni->ni_fhdwell >> 8) & 0x00ff;
410                        *frm++ = IEEE80211_FH_CHANSET(
411			    ieee80211_chan2ieee(ic, ni->ni_chan));
412                        *frm++ = IEEE80211_FH_CHANPAT(
413			    ieee80211_chan2ieee(ic, ni->ni_chan));
414                        *frm++ = ni->ni_fhindex;
415		} else {
416			*frm++ = IEEE80211_ELEMID_DSPARMS;
417			*frm++ = 1;
418			*frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
419		}
420
421		if (ic->ic_opmode == IEEE80211_M_IBSS) {
422			*frm++ = IEEE80211_ELEMID_IBSSPARMS;
423			*frm++ = 2;
424			*frm++ = 0; *frm++ = 0;		/* TODO: ATIM window */
425		} else {	/* IEEE80211_M_HOSTAP */
426			/* TODO: TIM */
427			*frm++ = IEEE80211_ELEMID_TIM;
428			*frm++ = 4;	/* length */
429			*frm++ = 0;	/* DTIM count */
430			*frm++ = 1;	/* DTIM period */
431			*frm++ = 0;	/* bitmap control */
432			*frm++ = 0;	/* Partial Virtual Bitmap (variable length) */
433		}
434		frm = ieee80211_add_xrates(frm, &ic->ic_bss->ni_rates);
435		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
436		break;
437
438	case IEEE80211_FC0_SUBTYPE_AUTH:
439		MGETHDR(m, M_DONTWAIT, MT_DATA);
440		if (m == NULL)
441			senderr(ENOMEM, is_tx_nombuf);
442		MH_ALIGN(m, 2 * 3);
443		m->m_pkthdr.len = m->m_len = 6;
444		frm = mtod(m, u_int8_t *);
445		/* TODO: shared key auth */
446		((u_int16_t *)frm)[0] = htole16(IEEE80211_AUTH_ALG_OPEN);
447		((u_int16_t *)frm)[1] = htole16(arg);	/* sequence number */
448		((u_int16_t *)frm)[2] = 0;		/* status */
449		if (ic->ic_opmode == IEEE80211_M_STA)
450			timer = IEEE80211_TRANS_WAIT;
451		break;
452
453	case IEEE80211_FC0_SUBTYPE_DEAUTH:
454		if (ifp->if_flags & IFF_DEBUG)
455			if_printf(ifp, "station %s deauthenticate (reason %d)\n",
456			    ether_sprintf(ni->ni_macaddr), arg);
457		MGETHDR(m, M_DONTWAIT, MT_DATA);
458		if (m == NULL)
459			senderr(ENOMEM, is_tx_nombuf);
460		MH_ALIGN(m, 2);
461		m->m_pkthdr.len = m->m_len = 2;
462		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
463		break;
464
465	case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
466	case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
467		/*
468		 * asreq frame format
469		 *	[2] capability information
470		 *	[2] listen interval
471		 *	[6*] current AP address (reassoc only)
472		 *	[tlv] ssid
473		 *	[tlv] supported rates
474		 *	[tlv] extended supported rates
475		 */
476		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
477			 sizeof(capinfo)
478		       + sizeof(u_int16_t)
479		       + IEEE80211_ADDR_LEN
480		       + 2 + ni->ni_esslen
481		       + 2 + IEEE80211_RATE_SIZE
482		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
483		if (m == NULL)
484			senderr(ENOMEM, is_tx_nombuf);
485		m->m_data += sizeof(struct ieee80211_frame);
486		frm = mtod(m, u_int8_t *);
487
488		capinfo = 0;
489		if (ic->ic_opmode == IEEE80211_M_IBSS)
490			capinfo |= IEEE80211_CAPINFO_IBSS;
491		else		/* IEEE80211_M_STA */
492			capinfo |= IEEE80211_CAPINFO_ESS;
493		if (ic->ic_flags & IEEE80211_F_WEPON)
494			capinfo |= IEEE80211_CAPINFO_PRIVACY;
495		/*
496		 * NB: Some 11a AP's reject the request when
497		 *     short premable is set.
498		 */
499		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
500		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
501			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
502		if (ic->ic_flags & IEEE80211_F_SHSLOT)
503			capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
504		*(u_int16_t *)frm = htole16(capinfo);
505		frm += 2;
506
507		*(u_int16_t *)frm = htole16(ic->ic_lintval);
508		frm += 2;
509
510		if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
511			IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
512			frm += IEEE80211_ADDR_LEN;
513		}
514
515		frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
516		frm = ieee80211_add_rates(frm, &ni->ni_rates);
517		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
518		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
519
520		timer = IEEE80211_TRANS_WAIT;
521		break;
522
523	case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
524	case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
525		/*
526		 * asreq frame format
527		 *	[2] capability information
528		 *	[2] status
529		 *	[2] association ID
530		 *	[tlv] supported rates
531		 *	[tlv] extended supported rates
532		 */
533		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
534			 sizeof(capinfo)
535		       + sizeof(u_int16_t)
536		       + sizeof(u_int16_t)
537		       + 2 + IEEE80211_RATE_SIZE
538		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
539		if (m == NULL)
540			senderr(ENOMEM, is_tx_nombuf);
541		m->m_data += sizeof(struct ieee80211_frame);
542		frm = mtod(m, u_int8_t *);
543
544		capinfo = IEEE80211_CAPINFO_ESS;
545		if (ic->ic_flags & IEEE80211_F_WEPON)
546			capinfo |= IEEE80211_CAPINFO_PRIVACY;
547		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
548		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
549			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
550		*(u_int16_t *)frm = htole16(capinfo);
551		frm += 2;
552
553		*(u_int16_t *)frm = htole16(arg);	/* status */
554		frm += 2;
555
556		if (arg == IEEE80211_STATUS_SUCCESS)
557			*(u_int16_t *)frm = htole16(ni->ni_associd);
558		frm += 2;
559
560		frm = ieee80211_add_rates(frm, &ni->ni_rates);
561		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
562		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
563		break;
564
565	case IEEE80211_FC0_SUBTYPE_DISASSOC:
566		if (ifp->if_flags & IFF_DEBUG)
567			if_printf(ifp, "station %s disassociate (reason %d)\n",
568			    ether_sprintf(ni->ni_macaddr), arg);
569		MGETHDR(m, M_DONTWAIT, MT_DATA);
570		if (m == NULL)
571			senderr(ENOMEM, is_tx_nombuf);
572		MH_ALIGN(m, 2);
573		m->m_pkthdr.len = m->m_len = 2;
574		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
575		break;
576
577	default:
578		IEEE80211_DPRINTF(("%s: invalid mgmt frame type %u\n",
579			__func__, type));
580		senderr(EINVAL, is_tx_unknownmgt);
581		/* NOTREACHED */
582	}
583
584	ret = ieee80211_mgmt_output(ifp, ni, m, type);
585	if (ret == 0) {
586		if (timer)
587			ic->ic_mgt_timer = timer;
588	} else {
589bad:
590		if (ni != ic->ic_bss)		/* remove ref we added */
591			ieee80211_free_node(ic, ni);
592	}
593	return ret;
594#undef senderr
595}
596