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ieee80211_output.c revision 1.18
      1 /*	$NetBSD: ieee80211_output.c,v 1.18 2004/12/19 08:08:06 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 1.18 2004/12/19 08:08:06 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 #ifdef IEEE80211_DEBUG
     94 /*
     95  * Decide if an outbound management frame should be
     96  * printed when debugging is enabled.  This filters some
     97  * of the less interesting frames that come frequently
     98  * (e.g. beacons).
     99  */
    100 static __inline int
    101 doprint(struct ieee80211com *ic, int subtype)
    102 {
    103 	switch (subtype) {
    104 	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
    105 		return (ic->ic_opmode == IEEE80211_M_IBSS);
    106 	}
    107 	return 1;
    108 }
    109 #endif
    110 
    111 /*
    112  * Send a management frame to the specified node.  The node pointer
    113  * must have a reference as the pointer will be passed to the driver
    114  * and potentially held for a long time.  If the frame is successfully
    115  * dispatched to the driver, then it is responsible for freeing the
    116  * reference (and potentially free'ing up any associated storage).
    117  */
    118 static int
    119 ieee80211_mgmt_output(struct ifnet *ifp, struct ieee80211_node *ni,
    120     struct mbuf *m, int type)
    121 {
    122 	struct ieee80211com *ic = (void *)ifp;
    123 	struct ieee80211_frame *wh;
    124 
    125 	IASSERT(ni != NULL, ("null node"));
    126 	ni->ni_inact = 0;
    127 
    128 	/*
    129 	 * Yech, hack alert!  We want to pass the node down to the
    130 	 * driver's start routine.  If we don't do so then the start
    131 	 * routine must immediately look it up again and that can
    132 	 * cause a lock order reversal if, for example, this frame
    133 	 * is being sent because the station is being timedout and
    134 	 * the frame being sent is a DEAUTH message.  We could stick
    135 	 * this in an m_tag and tack that on to the mbuf.  However
    136 	 * that's rather expensive to do for every frame so instead
    137 	 * we stuff it in the rcvif field since outbound frames do
    138 	 * not (presently) use this.
    139 	 */
    140 	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
    141 	if (m == NULL)
    142 		return ENOMEM;
    143 #ifdef __FreeBSD__
    144 	KASSERT(m->m_pkthdr.rcvif == NULL, ("rcvif not null"));
    145 #endif
    146 	m->m_pkthdr.rcvif = (void *)ni;
    147 
    148 	wh = mtod(m, struct ieee80211_frame *);
    149 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT | type;
    150 	wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
    151 	*(u_int16_t *)&wh->i_dur[0] = 0;
    152 	*(u_int16_t *)&wh->i_seq[0] =
    153 	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
    154 	ni->ni_txseq++;
    155 	IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_macaddr);
    156 	IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
    157 	IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
    158 
    159 	if ((m->m_flags & M_LINK0) != 0 && ni->ni_challenge != NULL) {
    160 		m->m_flags &= ~M_LINK0;
    161 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
    162 			("%s: encrypting frame for %s\n",
    163 			__func__, ether_sprintf(wh->i_addr1)));
    164 		wh->i_fc[1] |= IEEE80211_FC1_WEP;
    165 	}
    166 #ifdef IEEE80211_DEBUG
    167 	/* avoid printing too many frames */
    168 	if ((ieee80211_msg_debug(ic) && doprint(ic, type)) ||
    169 	    ieee80211_msg_dumppkts(ic)) {
    170 		if_printf(ifp, "sending %s to %s on channel %u\n",
    171 		    ieee80211_mgt_subtype_name[
    172 		    (type & IEEE80211_FC0_SUBTYPE_MASK)
    173 		    >> IEEE80211_FC0_SUBTYPE_SHIFT],
    174 		    ether_sprintf(ni->ni_macaddr),
    175 		    ieee80211_chan2ieee(ic, ni->ni_chan));
    176 	}
    177 #endif
    178 	IF_ENQUEUE(&ic->ic_mgtq, m);
    179 	ifp->if_timer = 1;
    180 	(*ifp->if_start)(ifp);
    181 	return 0;
    182 }
    183 
    184 /*
    185  * Encapsulate an outbound data frame.  The mbuf chain is updated and
    186  * a reference to the destination node is returned.  If an error is
    187  * encountered NULL is returned and the node reference will also be NULL.
    188  *
    189  * NB: The caller is responsible for free'ing a returned node reference.
    190  *     The convention is ic_bss is not reference counted; the caller must
    191  *     maintain that.
    192  */
    193 struct mbuf *
    194 ieee80211_encap(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node **pni)
    195 {
    196 	struct ieee80211com *ic = (void *)ifp;
    197 	struct ether_header eh;
    198 	struct ieee80211_frame *wh;
    199 	struct ieee80211_node *ni = NULL;
    200 	struct llc *llc;
    201 
    202 	if (m->m_len < sizeof(struct ether_header)) {
    203 		m = m_pullup(m, sizeof(struct ether_header));
    204 		if (m == NULL) {
    205 			ic->ic_stats.is_tx_nombuf++;
    206 			goto bad;
    207 		}
    208 	}
    209 	memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
    210 
    211 	ni = ieee80211_find_txnode(ic, eh.ether_dhost);
    212 	if (ni == NULL) {
    213 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_OUTPUT,
    214 			("%s: no node for dst %s, discard frame\n",
    215 			__func__, ether_sprintf(eh.ether_dhost)));
    216 		ic->ic_stats.is_tx_nonode++;
    217 		goto bad;
    218 	}
    219 	ni->ni_inact = 0;
    220 
    221 	m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
    222 	llc = mtod(m, struct llc *);
    223 	llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
    224 	llc->llc_control = LLC_UI;
    225 	llc->llc_snap.org_code[0] = 0;
    226 	llc->llc_snap.org_code[1] = 0;
    227 	llc->llc_snap.org_code[2] = 0;
    228 	llc->llc_snap.ether_type = eh.ether_type;
    229 	M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
    230 	if (m == NULL) {
    231 		ic->ic_stats.is_tx_nombuf++;
    232 		goto bad;
    233 	}
    234 	wh = mtod(m, struct ieee80211_frame *);
    235 	wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
    236 	*(u_int16_t *)&wh->i_dur[0] = 0;
    237 	*(u_int16_t *)&wh->i_seq[0] =
    238 	    htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
    239 	ni->ni_txseq++;
    240 	switch (ic->ic_opmode) {
    241 	case IEEE80211_M_STA:
    242 		wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
    243 		IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
    244 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
    245 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
    246 		break;
    247 	case IEEE80211_M_IBSS:
    248 	case IEEE80211_M_AHDEMO:
    249 		wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
    250 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
    251 		IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
    252 		IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
    253 		break;
    254 	case IEEE80211_M_HOSTAP:
    255 		wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
    256 		IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
    257 		IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
    258 		IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
    259 		break;
    260 	case IEEE80211_M_MONITOR:
    261 		goto bad;
    262 	}
    263 	if (ic->ic_flags & IEEE80211_F_PRIVACY)
    264 		wh->i_fc[1] |= IEEE80211_FC1_WEP;
    265 	*pni = ni;
    266 	return m;
    267 bad:
    268 	if (m != NULL)
    269 		m_freem(m);
    270 	if (ni != NULL)
    271 		ieee80211_release_node(ic, ni);
    272 	*pni = NULL;
    273 	return NULL;
    274 }
    275 
    276 /*
    277  * Arguments in:
    278  *
    279  * paylen:  payload length (no FCS, no WEP header)
    280  *
    281  * hdrlen:  header length
    282  *
    283  * rate:    MSDU speed, units 500kb/s
    284  *
    285  * flags:   IEEE80211_F_SHPREAMBLE (use short preamble),
    286  *          IEEE80211_F_SHSLOT (use short slot length)
    287  *
    288  * Arguments out:
    289  *
    290  * d:       802.11 Duration field for data frame,
    291  *          PLCP Length for data frame,
    292  *          PLCP Service field for data frame,
    293  *          802.11 Duration field for RTS
    294  */
    295 static int
    296 ieee80211_compute_duration1(int len, uint32_t flags, int rate,
    297     struct ieee80211_duration *d)
    298 {
    299 	int ack, bitlen, cts, data_dur, remainder;
    300 
    301 	/* RTS reserves medium for SIFS | CTS | SIFS | (DATA) | SIFS | ACK
    302 	 * DATA reserves medium for SIFS | ACK
    303 	 */
    304 
    305 	bitlen = len * 8;
    306 
    307 #if 0
    308 	/* RTS is always sent at 1 Mb/s.  (XXX Really?) */
    309 	d->d_rts_plcp_len = sizeof(struct ieee80211_frame_rts) * 8;
    310 #endif
    311 	d->d_plcp_svc = 0;
    312 
    313 	switch (rate) {
    314 	case 2:		/* 1 Mb/s */
    315 	case 4:		/* 2 Mb/s */
    316 		data_dur = (bitlen * 2) / rate;
    317 
    318 		/* 1 - 2 Mb/s WLAN: send ACK/CTS at 1 Mb/s */
    319 		cts = IEEE80211_DUR_DS_SLOW_CTS;
    320 		ack = IEEE80211_DUR_DS_SLOW_ACK;
    321 		break;
    322 	case 44:	/* 22  Mb/s */
    323 		d->d_plcp_svc = IEEE80211_PLCP_SERVICE_PBCC;
    324 		/*FALLTHROUGH*/
    325 	case 11:	/* 5.5 Mb/s */
    326 	case 22:	/* 11  Mb/s */
    327 		remainder = (bitlen * 2) % rate;
    328 
    329 		if (remainder != 0)
    330 			data_dur = (bitlen * 2) / rate + 1;
    331 		else
    332 			data_dur = (bitlen * 2) / rate;
    333 
    334 		if (rate == 22 && remainder <= 6)
    335 			d->d_plcp_svc |= IEEE80211_PLCP_SERVICE_LENEXT;
    336 
    337 		/* 5.5 - 11 Mb/s WLAN: send ACK/CTS at 2 Mb/s */
    338 		cts = IEEE80211_DUR_DS_FAST_CTS;
    339 		ack = IEEE80211_DUR_DS_FAST_ACK;
    340 		break;
    341 	default:
    342 		/* TBD */
    343 		return -1;
    344 	}
    345 
    346 	d->d_rts_dur = data_dur + 3 * (IEEE80211_DUR_DS_SIFS +
    347 	    IEEE80211_DUR_DS_SHORT_PREAMBLE +
    348 	    IEEE80211_DUR_DS_FAST_PLCPHDR) + cts + ack;
    349 	d->d_data_dur = data_dur + IEEE80211_DUR_DS_SIFS +
    350 	    2 * (IEEE80211_DUR_DS_SHORT_PREAMBLE +
    351 	         IEEE80211_DUR_DS_FAST_PLCPHDR) + ack;
    352 
    353 	d->d_plcp_len = data_dur;
    354 
    355 	if ((flags & IEEE80211_F_SHPREAMBLE) != 0)
    356 		return 0;
    357 
    358 	d->d_rts_dur += 3 * (IEEE80211_DUR_DS_LONG_PREAMBLE -
    359 			     IEEE80211_DUR_DS_SHORT_PREAMBLE) +
    360 			3 * (IEEE80211_DUR_DS_SLOW_PLCPHDR -
    361 			     IEEE80211_DUR_DS_FAST_PLCPHDR);
    362 	d->d_data_dur += 2 * (IEEE80211_DUR_DS_LONG_PREAMBLE -
    363 			      IEEE80211_DUR_DS_SHORT_PREAMBLE) +
    364 			 2 * (IEEE80211_DUR_DS_SLOW_PLCPHDR -
    365 			      IEEE80211_DUR_DS_FAST_PLCPHDR);
    366 	return 0;
    367 }
    368 
    369 /*
    370  * Arguments in:
    371  *
    372  * wh:      802.11 header
    373  *
    374  * paylen:  payload length (no FCS, no WEP header)
    375  *
    376  * rate:    MSDU speed, units 500kb/s
    377  *
    378  * fraglen: fragment length, set to maximum (or higher) for no
    379  *          fragmentation
    380  *
    381  * flags:   IEEE80211_F_PRIVACY (hardware adds WEP),
    382  *          IEEE80211_F_SHPREAMBLE (use short preamble),
    383  *          IEEE80211_F_SHSLOT (use short slot length)
    384  *
    385  * Arguments out:
    386  *
    387  * d0: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
    388  *     of first/only fragment
    389  *
    390  * dn: 802.11 Duration fields (RTS/Data), PLCP Length, Service fields
    391  *     of first/only fragment
    392  */
    393 int
    394 ieee80211_compute_duration(struct ieee80211_frame *wh, int paylen,
    395     uint32_t flags, int fraglen, int rate, struct ieee80211_duration *d0,
    396     struct ieee80211_duration *dn, int *npktp)
    397 {
    398 	int rc;
    399 	int firstlen, hdrlen, lastlen, lastlen0, npkt, overlen;
    400 
    401 	if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
    402 		hdrlen = sizeof(struct ieee80211_frame_addr4);
    403 	else
    404 		hdrlen = sizeof(struct ieee80211_frame);
    405 
    406 	if ((flags & IEEE80211_F_PRIVACY) != 0) {
    407 		overlen = IEEE80211_WEP_TOTLEN + IEEE80211_CRC_LEN;
    408 #if 0	/* 802.11 lets us extend a fragment's length by the length of
    409 	 * a WEP header, AFTER fragmentation.  Might want to disable
    410 	 * this while fancy link adaptations are running.
    411 	 */
    412 		fraglen -= IEEE80211_WEP_TOTLEN;
    413 #endif
    414 #if 0	/* Ditto CRC? */
    415 		fraglen -= IEEE80211_CRC_LEN;
    416 #endif
    417 	} else
    418 		overlen = IEEE80211_CRC_LEN;
    419 
    420 	npkt = paylen / fraglen;
    421 	lastlen0 = paylen % fraglen;
    422 
    423 	if (npkt == 0) {
    424 		/* no fragments */
    425 		lastlen = paylen + overlen;
    426 	} else if (lastlen0 != 0) {
    427 		/* a short fragment */
    428 		lastlen = lastlen0 + overlen;
    429 		npkt++;
    430 	} else
    431 		lastlen = fraglen + overlen;
    432 
    433 	if (npktp != NULL)
    434 		*npktp = npkt;
    435 
    436 	if (npkt > 1)
    437 		firstlen = fraglen + overlen;
    438 	else
    439 		firstlen = paylen + overlen;
    440 
    441 	rc = ieee80211_compute_duration1(firstlen + hdrlen, flags, rate, d0);
    442 	if (rc == -1)
    443 		return rc;
    444 	if (npkt > 1) {
    445 		*dn = *d0;
    446 		return 0;
    447 	}
    448 	return ieee80211_compute_duration1(lastlen + hdrlen, flags, rate, dn);
    449 }
    450 
    451 /*
    452  * Add a supported rates element id to a frame.
    453  */
    454 u_int8_t *
    455 ieee80211_add_rates(u_int8_t *frm, const struct ieee80211_rateset *rs)
    456 {
    457 	int nrates;
    458 
    459 	*frm++ = IEEE80211_ELEMID_RATES;
    460 	nrates = rs->rs_nrates;
    461 	if (nrates > IEEE80211_RATE_SIZE)
    462 		nrates = IEEE80211_RATE_SIZE;
    463 	*frm++ = nrates;
    464 	memcpy(frm, rs->rs_rates, nrates);
    465 	return frm + nrates;
    466 }
    467 
    468 /*
    469  * Add an extended supported rates element id to a frame.
    470  */
    471 u_int8_t *
    472 ieee80211_add_xrates(u_int8_t *frm, const struct ieee80211_rateset *rs)
    473 {
    474 	/*
    475 	 * Add an extended supported rates element if operating in 11g mode.
    476 	 */
    477 	if (rs->rs_nrates > IEEE80211_RATE_SIZE) {
    478 		int nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
    479 		*frm++ = IEEE80211_ELEMID_XRATES;
    480 		*frm++ = nrates;
    481 		memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
    482 		frm += nrates;
    483 	}
    484 	return frm;
    485 }
    486 
    487 /*
    488  * Add an ssid elemet to a frame.
    489  */
    490 static u_int8_t *
    491 ieee80211_add_ssid(u_int8_t *frm, const u_int8_t *ssid, u_int len)
    492 {
    493 	*frm++ = IEEE80211_ELEMID_SSID;
    494 	*frm++ = len;
    495 	memcpy(frm, ssid, len);
    496 	return frm + len;
    497 }
    498 
    499 static struct mbuf *
    500 ieee80211_getmbuf(int flags, int type, u_int pktlen)
    501 {
    502 	struct mbuf *m;
    503 
    504 	IASSERT(pktlen <= MCLBYTES, ("802.11 packet too large: %u", pktlen));
    505 #ifdef __FreeBSD__
    506 	if (pktlen <= MHLEN)
    507 		MGETHDR(m, flags, type);
    508 	else
    509 		m = m_getcl(flags, type, M_PKTHDR);
    510 #else
    511 	MGETHDR(m, flags, type);
    512 	if (m != NULL && pktlen > MHLEN)
    513 		MCLGET(m, flags);
    514 #endif
    515 	return m;
    516 }
    517 
    518 /*
    519  * Send a management frame.  The node is for the destination (or ic_bss
    520  * when in station mode).  Nodes other than ic_bss have their reference
    521  * count bumped to reflect our use for an indeterminant time.
    522  */
    523 int
    524 ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
    525 	int type, int arg)
    526 {
    527 #define	senderr(_x, _v)	do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
    528 	struct ifnet *ifp = &ic->ic_if;
    529 	struct mbuf *m;
    530 	u_int8_t *frm;
    531 	enum ieee80211_phymode mode;
    532 	u_int16_t capinfo;
    533 	int has_challenge, is_shared_key, ret, timer;
    534 
    535 	IASSERT(ni != NULL, ("null node"));
    536 
    537 	/*
    538 	 * Hold a reference on the node so it doesn't go away until after
    539 	 * the xmit is complete all the way in the driver.  On error we
    540 	 * will remove our reference.
    541 	 */
    542 	ieee80211_ref_node(ni);
    543 	timer = 0;
    544 	switch (type) {
    545 	case IEEE80211_FC0_SUBTYPE_PROBE_REQ:
    546 		/*
    547 		 * prreq frame format
    548 		 *	[tlv] ssid
    549 		 *	[tlv] supported rates
    550 		 *	[tlv] extended supported rates
    551 		 */
    552 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
    553 			 2 + ic->ic_des_esslen
    554 		       + 2 + IEEE80211_RATE_SIZE
    555 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
    556 		if (m == NULL)
    557 			senderr(ENOMEM, is_tx_nombuf);
    558 		m->m_data += sizeof(struct ieee80211_frame);
    559 		frm = mtod(m, u_int8_t *);
    560 		frm = ieee80211_add_ssid(frm, ic->ic_des_essid, ic->ic_des_esslen);
    561 		mode = ieee80211_chan2mode(ic, ni->ni_chan);
    562 		frm = ieee80211_add_rates(frm, &ic->ic_sup_rates[mode]);
    563 		frm = ieee80211_add_xrates(frm, &ic->ic_sup_rates[mode]);
    564 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
    565 
    566 		timer = IEEE80211_TRANS_WAIT;
    567 		break;
    568 
    569 	case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
    570 		/*
    571 		 * probe response frame format
    572 		 *	[8] time stamp
    573 		 *	[2] beacon interval
    574 		 *	[2] cabability information
    575 		 *	[tlv] ssid
    576 		 *	[tlv] supported rates
    577 		 *	[tlv] parameter set (FH/DS)
    578 		 *	[tlv] parameter set (IBSS)
    579 		 *	[tlv] extended supported rates
    580 		 */
    581 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
    582 			 8 + 2 + 2 + 2
    583 		       + 2 + ni->ni_esslen
    584 		       + 2 + IEEE80211_RATE_SIZE
    585 		       + (ic->ic_phytype == IEEE80211_T_FH ? 7 : 3)
    586 		       + 6
    587 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
    588 		if (m == NULL)
    589 			senderr(ENOMEM, is_tx_nombuf);
    590 		m->m_data += sizeof(struct ieee80211_frame);
    591 		frm = mtod(m, u_int8_t *);
    592 
    593 		memset(frm, 0, 8);	/* timestamp should be filled later */
    594 		frm += 8;
    595 		*(u_int16_t *)frm = htole16(ic->ic_bss->ni_intval);
    596 		frm += 2;
    597 		if (ic->ic_opmode == IEEE80211_M_IBSS)
    598 			capinfo = IEEE80211_CAPINFO_IBSS;
    599 		else
    600 			capinfo = IEEE80211_CAPINFO_ESS;
    601 		if (ic->ic_flags & IEEE80211_F_PRIVACY)
    602 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
    603 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
    604 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
    605 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
    606 		*(u_int16_t *)frm = htole16(capinfo);
    607 		frm += 2;
    608 
    609 		frm = ieee80211_add_ssid(frm, ic->ic_bss->ni_essid,
    610 				ic->ic_bss->ni_esslen);
    611 		frm = ieee80211_add_rates(frm, &ic->ic_bss->ni_rates);
    612 
    613 		if (ic->ic_phytype == IEEE80211_T_FH) {
    614                         *frm++ = IEEE80211_ELEMID_FHPARMS;
    615                         *frm++ = 5;
    616                         *frm++ = ni->ni_fhdwell & 0x00ff;
    617                         *frm++ = (ni->ni_fhdwell >> 8) & 0x00ff;
    618                         *frm++ = IEEE80211_FH_CHANSET(
    619 			    ieee80211_chan2ieee(ic, ni->ni_chan));
    620                         *frm++ = IEEE80211_FH_CHANPAT(
    621 			    ieee80211_chan2ieee(ic, ni->ni_chan));
    622                         *frm++ = ni->ni_fhindex;
    623 		} else {
    624 			*frm++ = IEEE80211_ELEMID_DSPARMS;
    625 			*frm++ = 1;
    626 			*frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
    627 		}
    628 
    629 		if (ic->ic_opmode == IEEE80211_M_IBSS) {
    630 			*frm++ = IEEE80211_ELEMID_IBSSPARMS;
    631 			*frm++ = 2;
    632 			*frm++ = 0; *frm++ = 0;		/* TODO: ATIM window */
    633 		} else {	/* IEEE80211_M_HOSTAP */
    634 			/* TODO: TIM */
    635 			*frm++ = IEEE80211_ELEMID_TIM;
    636 			*frm++ = 4;	/* length */
    637 			*frm++ = 0;	/* DTIM count */
    638 			*frm++ = 1;	/* DTIM period */
    639 			*frm++ = 0;	/* bitmap control */
    640 			*frm++ = 0;	/* Partial Virtual Bitmap (variable length) */
    641 		}
    642 		frm = ieee80211_add_xrates(frm, &ic->ic_bss->ni_rates);
    643 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
    644 		break;
    645 
    646 	case IEEE80211_FC0_SUBTYPE_AUTH:
    647 		MGETHDR(m, M_DONTWAIT, MT_DATA);
    648 		if (m == NULL)
    649 			senderr(ENOMEM, is_tx_nombuf);
    650 
    651 		has_challenge = ((arg == IEEE80211_AUTH_SHARED_CHALLENGE ||
    652 		    arg == IEEE80211_AUTH_SHARED_RESPONSE) &&
    653 		    ni->ni_challenge != NULL);
    654 
    655 		is_shared_key = has_challenge || (ni->ni_challenge != NULL &&
    656 		    arg == IEEE80211_AUTH_SHARED_PASS);
    657 
    658 		if (has_challenge) {
    659 			MH_ALIGN(m, 2 * 3 + 2 + IEEE80211_CHALLENGE_LEN);
    660 			m->m_pkthdr.len = m->m_len =
    661 			    2 * 3 + 2 + IEEE80211_CHALLENGE_LEN;
    662 		} else {
    663 			MH_ALIGN(m, 2 * 3);
    664 			m->m_pkthdr.len = m->m_len = 2 * 3;
    665 		}
    666 		frm = mtod(m, u_int8_t *);
    667 		((u_int16_t *)frm)[0] =
    668 		    (is_shared_key) ? htole16(IEEE80211_AUTH_ALG_SHARED)
    669 		                    : htole16(IEEE80211_AUTH_ALG_OPEN);
    670 		((u_int16_t *)frm)[1] = htole16(arg);	/* sequence number */
    671 		((u_int16_t *)frm)[2] = 0;		/* status */
    672 
    673 		if (has_challenge) {
    674 			((u_int16_t *)frm)[3] =
    675 			    htole16((IEEE80211_CHALLENGE_LEN << 8) |
    676 			    IEEE80211_ELEMID_CHALLENGE);
    677 			memcpy(&((u_int16_t *)frm)[4], ni->ni_challenge,
    678 			    IEEE80211_CHALLENGE_LEN);
    679 			if (arg == IEEE80211_AUTH_SHARED_RESPONSE) {
    680 				IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
    681 				    ("%s: request encrypt frame\n", __func__));
    682 				m->m_flags |= M_LINK0; /* WEP-encrypt, please */
    683 			}
    684 		}
    685 		if (ic->ic_opmode == IEEE80211_M_STA)
    686 			timer = IEEE80211_TRANS_WAIT;
    687 		break;
    688 
    689 	case IEEE80211_FC0_SUBTYPE_DEAUTH:
    690 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_AUTH,
    691 			("send station %s deauthenticate (reason %d)\n",
    692 			ether_sprintf(ni->ni_macaddr), arg));
    693 		MGETHDR(m, M_DONTWAIT, MT_DATA);
    694 		if (m == NULL)
    695 			senderr(ENOMEM, is_tx_nombuf);
    696 		MH_ALIGN(m, 2);
    697 		m->m_pkthdr.len = m->m_len = 2;
    698 		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
    699 		break;
    700 
    701 	case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
    702 	case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
    703 		/*
    704 		 * asreq frame format
    705 		 *	[2] capability information
    706 		 *	[2] listen interval
    707 		 *	[6*] current AP address (reassoc only)
    708 		 *	[tlv] ssid
    709 		 *	[tlv] supported rates
    710 		 *	[tlv] extended supported rates
    711 		 */
    712 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
    713 			 sizeof(capinfo)
    714 		       + sizeof(u_int16_t)
    715 		       + IEEE80211_ADDR_LEN
    716 		       + 2 + ni->ni_esslen
    717 		       + 2 + IEEE80211_RATE_SIZE
    718 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
    719 		if (m == NULL)
    720 			senderr(ENOMEM, is_tx_nombuf);
    721 		m->m_data += sizeof(struct ieee80211_frame);
    722 		frm = mtod(m, u_int8_t *);
    723 
    724 		capinfo = 0;
    725 		if (ic->ic_opmode == IEEE80211_M_IBSS)
    726 			capinfo |= IEEE80211_CAPINFO_IBSS;
    727 		else		/* IEEE80211_M_STA */
    728 			capinfo |= IEEE80211_CAPINFO_ESS;
    729 		if (ic->ic_flags & IEEE80211_F_PRIVACY)
    730 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
    731 		/*
    732 		 * NB: Some 11a AP's reject the request when
    733 		 *     short premable is set.
    734 		 */
    735 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
    736 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
    737 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
    738 		if (ic->ic_flags & IEEE80211_F_SHSLOT)
    739 			capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
    740 		*(u_int16_t *)frm = htole16(capinfo);
    741 		frm += 2;
    742 
    743 		*(u_int16_t *)frm = htole16(ic->ic_lintval);
    744 		frm += 2;
    745 
    746 		if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
    747 			IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
    748 			frm += IEEE80211_ADDR_LEN;
    749 		}
    750 
    751 		frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
    752 		frm = ieee80211_add_rates(frm, &ni->ni_rates);
    753 		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
    754 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
    755 
    756 		timer = IEEE80211_TRANS_WAIT;
    757 		break;
    758 
    759 	case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
    760 	case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
    761 		/*
    762 		 * asreq frame format
    763 		 *	[2] capability information
    764 		 *	[2] status
    765 		 *	[2] association ID
    766 		 *	[tlv] supported rates
    767 		 *	[tlv] extended supported rates
    768 		 */
    769 		m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
    770 			 sizeof(capinfo)
    771 		       + sizeof(u_int16_t)
    772 		       + sizeof(u_int16_t)
    773 		       + 2 + IEEE80211_RATE_SIZE
    774 		       + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
    775 		if (m == NULL)
    776 			senderr(ENOMEM, is_tx_nombuf);
    777 		m->m_data += sizeof(struct ieee80211_frame);
    778 		frm = mtod(m, u_int8_t *);
    779 
    780 		capinfo = IEEE80211_CAPINFO_ESS;
    781 		if (ic->ic_flags & IEEE80211_F_PRIVACY)
    782 			capinfo |= IEEE80211_CAPINFO_PRIVACY;
    783 		if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
    784 		    IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
    785 			capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
    786 		*(u_int16_t *)frm = htole16(capinfo);
    787 		frm += 2;
    788 
    789 		*(u_int16_t *)frm = htole16(arg);	/* status */
    790 		frm += 2;
    791 
    792 		if (arg == IEEE80211_STATUS_SUCCESS)
    793 			*(u_int16_t *)frm = htole16(ni->ni_associd);
    794 		frm += 2;
    795 
    796 		frm = ieee80211_add_rates(frm, &ni->ni_rates);
    797 		frm = ieee80211_add_xrates(frm, &ni->ni_rates);
    798 		m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
    799 		break;
    800 
    801 	case IEEE80211_FC0_SUBTYPE_DISASSOC:
    802 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ASSOC,
    803 			("send station %s disassociate (reason %d)\n",
    804 			ether_sprintf(ni->ni_macaddr), arg));
    805 		MGETHDR(m, M_DONTWAIT, MT_DATA);
    806 		if (m == NULL)
    807 			senderr(ENOMEM, is_tx_nombuf);
    808 		MH_ALIGN(m, 2);
    809 		m->m_pkthdr.len = m->m_len = 2;
    810 		*mtod(m, u_int16_t *) = htole16(arg);	/* reason */
    811 		break;
    812 
    813 	default:
    814 		IEEE80211_DPRINTF(ic, IEEE80211_MSG_ANY,
    815 			("%s: invalid mgmt frame type %u\n", __func__, type));
    816 		senderr(EINVAL, is_tx_unknownmgt);
    817 		/* NOTREACHED */
    818 	}
    819 
    820 	ret = ieee80211_mgmt_output(ifp, ni, m, type);
    821 	if (ret == 0) {
    822 		if (timer)
    823 			ic->ic_mgt_timer = timer;
    824 	} else {
    825 bad:
    826 		ieee80211_release_node(ic, ni);
    827 	}
    828 	return ret;
    829 #undef senderr
    830 }
    831 
    832 void
    833 ieee80211_pwrsave(struct ieee80211com *ic, struct ieee80211_node *ni,
    834 		  struct mbuf *m)
    835 {
    836 	/* Store the new packet on our queue, changing the TIM if necessary */
    837 
    838 	if (IF_IS_EMPTY(&ni->ni_savedq)) {
    839 		ic->ic_set_tim(ic, ni->ni_associd, 1);
    840 	}
    841 	if (ni->ni_savedq.ifq_len >= IEEE80211_PS_MAX_QUEUE) {
    842 		IF_DROP(&ni->ni_savedq);
    843 		m_freem(m);
    844 		if (ic->ic_if.if_flags & IFF_DEBUG)
    845 			printf("%s: station %s power save queue overflow"
    846 			       " of size %d drops %d\n",
    847 			       ic->ic_if.if_xname,
    848 			       ether_sprintf(ni->ni_macaddr),
    849 			       IEEE80211_PS_MAX_QUEUE,
    850 			       ni->ni_savedq.ifq_drops);
    851 	} else {
    852 		/* Similar to ieee80211_mgmt_output, store the node in
    853 		 * the rcvif field.
    854 		 */
    855 		IF_ENQUEUE(&ni->ni_savedq, m);
    856 		m->m_pkthdr.rcvif = (void *)ni;
    857 	}
    858 }
    859 
    860