The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_output.c

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    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: releng/5.3/sys/net80211/ieee80211_output.c 132712 2004-07-27 23:20:45Z rwatson $");
   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  */
   76 static int
   77 ieee80211_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         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  */
  146 struct mbuf *
  147 ieee80211_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         ni = ieee80211_find_txnode(ic, eh.ether_dhost);
  165         if (ni == NULL) {
  166                 IEEE80211_DPRINTF(("%s: no node for dst %s, discard frame\n",
  167                         __func__, ether_sprintf(eh.ether_dhost)));
  168                 ic->ic_stats.is_tx_nonode++; 
  169                 goto bad;
  170         }
  171         ni->ni_inact = 0;
  172 
  173         m_adj(m, sizeof(struct ether_header) - sizeof(struct llc));
  174         llc = mtod(m, struct llc *);
  175         llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
  176         llc->llc_control = LLC_UI;
  177         llc->llc_snap.org_code[0] = 0;
  178         llc->llc_snap.org_code[1] = 0;
  179         llc->llc_snap.org_code[2] = 0;
  180         llc->llc_snap.ether_type = eh.ether_type;
  181         M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
  182         if (m == NULL) {
  183                 ic->ic_stats.is_tx_nombuf++;
  184                 goto bad;
  185         }
  186         wh = mtod(m, struct ieee80211_frame *);
  187         wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
  188         *(u_int16_t *)wh->i_dur = 0;
  189         *(u_int16_t *)wh->i_seq =
  190             htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
  191         ni->ni_txseq++;
  192         switch (ic->ic_opmode) {
  193         case IEEE80211_M_STA:
  194                 wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
  195                 IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
  196                 IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
  197                 IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
  198                 break;
  199         case IEEE80211_M_IBSS:
  200         case IEEE80211_M_AHDEMO:
  201                 wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
  202                 IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
  203                 IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
  204                 IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
  205                 break;
  206         case IEEE80211_M_HOSTAP:
  207                 wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
  208                 IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
  209                 IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
  210                 IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
  211                 break;
  212         case IEEE80211_M_MONITOR:
  213                 goto bad;
  214         }
  215         *pni = ni;
  216         return m;
  217 bad:
  218         if (m != NULL)
  219                 m_freem(m);
  220         if (ni && ni != ic->ic_bss)
  221                 ieee80211_free_node(ic, ni);
  222         *pni = NULL;
  223         return NULL;
  224 }
  225 
  226 /*
  227  * Add a supported rates element id to a frame.
  228  */
  229 u_int8_t *
  230 ieee80211_add_rates(u_int8_t *frm, const struct ieee80211_rateset *rs)
  231 {
  232         int nrates;
  233 
  234         *frm++ = IEEE80211_ELEMID_RATES;
  235         nrates = rs->rs_nrates;
  236         if (nrates > IEEE80211_RATE_SIZE)
  237                 nrates = IEEE80211_RATE_SIZE;
  238         *frm++ = nrates;
  239         memcpy(frm, rs->rs_rates, nrates);
  240         return frm + nrates;
  241 }
  242 
  243 /*
  244  * Add an extended supported rates element id to a frame.
  245  */
  246 u_int8_t *
  247 ieee80211_add_xrates(u_int8_t *frm, const struct ieee80211_rateset *rs)
  248 {
  249         /*
  250          * Add an extended supported rates element if operating in 11g mode.
  251          */
  252         if (rs->rs_nrates > IEEE80211_RATE_SIZE) {
  253                 int nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
  254                 *frm++ = IEEE80211_ELEMID_XRATES;
  255                 *frm++ = nrates;
  256                 memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
  257                 frm += nrates;
  258         }
  259         return frm;
  260 }
  261 
  262 /* 
  263  * Add an ssid elemet to a frame.
  264  */
  265 static u_int8_t *
  266 ieee80211_add_ssid(u_int8_t *frm, const u_int8_t *ssid, u_int len)
  267 {
  268         *frm++ = IEEE80211_ELEMID_SSID;
  269         *frm++ = len;
  270         memcpy(frm, ssid, len);
  271         return frm + len;
  272 }
  273 
  274 static struct mbuf *
  275 ieee80211_getmbuf(int flags, int type, u_int pktlen)
  276 {
  277         struct mbuf *m;
  278 
  279         KASSERT(pktlen <= MCLBYTES, ("802.11 packet too large: %u", pktlen));
  280         if (pktlen <= MHLEN)
  281                 MGETHDR(m, flags, type);
  282         else
  283                 m = m_getcl(flags, type, M_PKTHDR);
  284         return m;
  285 }
  286 
  287 /*
  288  * Send a management frame.  The node is for the destination (or ic_bss
  289  * when in station mode).  Nodes other than ic_bss have their reference
  290  * count bumped to reflect our use for an indeterminant time.
  291  */
  292 int
  293 ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
  294         int type, int arg)
  295 {
  296 #define senderr(_x, _v) do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
  297         struct ifnet *ifp = &ic->ic_if;
  298         struct mbuf *m;
  299         u_int8_t *frm;
  300         enum ieee80211_phymode mode;
  301         u_int16_t capinfo;
  302         int ret, timer;
  303 
  304         KASSERT(ni != NULL, ("null node"));
  305 
  306         /*
  307          * Hold a reference on the node so it doesn't go away until after
  308          * the xmit is complete all the way in the driver.  On error we
  309          * will remove our reference.
  310          */
  311         if (ni != ic->ic_bss)
  312                 ieee80211_ref_node(ni);
  313         timer = 0;
  314         switch (type) {
  315         case IEEE80211_FC0_SUBTYPE_PROBE_REQ:
  316                 /*
  317                  * prreq frame format
  318                  *      [tlv] ssid
  319                  *      [tlv] supported rates
  320                  *      [tlv] extended supported rates
  321                  */
  322                 m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
  323                          2 + ic->ic_des_esslen
  324                        + 2 + IEEE80211_RATE_SIZE
  325                        + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
  326                 if (m == NULL)
  327                         senderr(ENOMEM, is_tx_nombuf);
  328                 m->m_data += sizeof(struct ieee80211_frame);
  329                 frm = mtod(m, u_int8_t *);
  330                 frm = ieee80211_add_ssid(frm, ic->ic_des_essid, ic->ic_des_esslen);
  331                 mode = ieee80211_chan2mode(ic, ni->ni_chan);
  332                 frm = ieee80211_add_rates(frm, &ic->ic_sup_rates[mode]);
  333                 frm = ieee80211_add_xrates(frm, &ic->ic_sup_rates[mode]);
  334                 m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  335 
  336                 timer = IEEE80211_TRANS_WAIT;
  337                 break;
  338 
  339         case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
  340                 /*
  341                  * probe response frame format
  342                  *      [8] time stamp
  343                  *      [2] beacon interval
  344                  *      [2] cabability information
  345                  *      [tlv] ssid
  346                  *      [tlv] supported rates
  347                  *      [tlv] parameter set (FH/DS)
  348                  *      [tlv] parameter set (IBSS)
  349                  *      [tlv] extended supported rates
  350                  */
  351                 m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
  352                          8 + 2 + 2 + 2
  353                        + 2 + ni->ni_esslen
  354                        + 2 + IEEE80211_RATE_SIZE
  355                        + (ic->ic_phytype == IEEE80211_T_FH ? 7 : 3)
  356                        + 6
  357                        + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
  358                 if (m == NULL)
  359                         senderr(ENOMEM, is_tx_nombuf);
  360                 m->m_data += sizeof(struct ieee80211_frame);
  361                 frm = mtod(m, u_int8_t *);
  362 
  363                 memset(frm, 0, 8);      /* timestamp should be filled later */
  364                 frm += 8;
  365                 *(u_int16_t *)frm = htole16(ic->ic_bss->ni_intval);
  366                 frm += 2;
  367                 if (ic->ic_opmode == IEEE80211_M_IBSS)
  368                         capinfo = IEEE80211_CAPINFO_IBSS;
  369                 else
  370                         capinfo = IEEE80211_CAPINFO_ESS;
  371                 if (ic->ic_flags & IEEE80211_F_WEPON)
  372                         capinfo |= IEEE80211_CAPINFO_PRIVACY;
  373                 if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
  374                     IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
  375                         capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
  376                 *(u_int16_t *)frm = htole16(capinfo);
  377                 frm += 2;
  378 
  379                 frm = ieee80211_add_ssid(frm, ic->ic_bss->ni_essid,
  380                                 ic->ic_bss->ni_esslen);
  381                 frm = ieee80211_add_rates(frm, &ic->ic_bss->ni_rates);
  382 
  383                 if (ic->ic_phytype == IEEE80211_T_FH) {
  384                         *frm++ = IEEE80211_ELEMID_FHPARMS;
  385                         *frm++ = 5;
  386                         *frm++ = ni->ni_fhdwell & 0x00ff;
  387                         *frm++ = (ni->ni_fhdwell >> 8) & 0x00ff;
  388                         *frm++ = IEEE80211_FH_CHANSET(
  389                             ieee80211_chan2ieee(ic, ni->ni_chan));
  390                         *frm++ = IEEE80211_FH_CHANPAT(
  391                             ieee80211_chan2ieee(ic, ni->ni_chan));
  392                         *frm++ = ni->ni_fhindex;
  393                 } else {
  394                         *frm++ = IEEE80211_ELEMID_DSPARMS;
  395                         *frm++ = 1;
  396                         *frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
  397                 }
  398 
  399                 if (ic->ic_opmode == IEEE80211_M_IBSS) {
  400                         *frm++ = IEEE80211_ELEMID_IBSSPARMS;
  401                         *frm++ = 2;
  402                         *frm++ = 0; *frm++ = 0;         /* TODO: ATIM window */
  403                 } else {        /* IEEE80211_M_HOSTAP */
  404                         /* TODO: TIM */
  405                         *frm++ = IEEE80211_ELEMID_TIM;
  406                         *frm++ = 4;     /* length */
  407                         *frm++ = 0;     /* DTIM count */
  408                         *frm++ = 1;     /* DTIM period */
  409                         *frm++ = 0;     /* bitmap control */
  410                         *frm++ = 0;     /* Partial Virtual Bitmap (variable length) */
  411                 }
  412                 frm = ieee80211_add_xrates(frm, &ic->ic_bss->ni_rates);
  413                 m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  414                 break;
  415 
  416         case IEEE80211_FC0_SUBTYPE_AUTH:
  417                 MGETHDR(m, M_DONTWAIT, MT_DATA);
  418                 if (m == NULL)
  419                         senderr(ENOMEM, is_tx_nombuf);
  420                 MH_ALIGN(m, 2 * 3);
  421                 m->m_pkthdr.len = m->m_len = 6;
  422                 frm = mtod(m, u_int8_t *);
  423                 /* TODO: shared key auth */
  424                 ((u_int16_t *)frm)[0] = htole16(IEEE80211_AUTH_ALG_OPEN);
  425                 ((u_int16_t *)frm)[1] = htole16(arg);   /* sequence number */
  426                 ((u_int16_t *)frm)[2] = 0;              /* status */
  427                 if (ic->ic_opmode == IEEE80211_M_STA)
  428                         timer = IEEE80211_TRANS_WAIT;
  429                 break;
  430 
  431         case IEEE80211_FC0_SUBTYPE_DEAUTH:
  432                 if (ifp->if_flags & IFF_DEBUG)
  433                         if_printf(ifp, "station %s deauthenticate (reason %d)\n",
  434                             ether_sprintf(ni->ni_macaddr), arg);
  435                 MGETHDR(m, M_DONTWAIT, MT_DATA);
  436                 if (m == NULL)
  437                         senderr(ENOMEM, is_tx_nombuf);
  438                 MH_ALIGN(m, 2);
  439                 m->m_pkthdr.len = m->m_len = 2;
  440                 *mtod(m, u_int16_t *) = htole16(arg);   /* reason */
  441                 break;
  442 
  443         case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
  444         case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
  445                 /*
  446                  * asreq frame format
  447                  *      [2] capability information
  448                  *      [2] listen interval
  449                  *      [6*] current AP address (reassoc only)
  450                  *      [tlv] ssid
  451                  *      [tlv] supported rates
  452                  *      [tlv] extended supported rates
  453                  */
  454                 m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
  455                          sizeof(capinfo)
  456                        + sizeof(u_int16_t)
  457                        + IEEE80211_ADDR_LEN
  458                        + 2 + ni->ni_esslen
  459                        + 2 + IEEE80211_RATE_SIZE
  460                        + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
  461                 if (m == NULL)
  462                         senderr(ENOMEM, is_tx_nombuf);
  463                 m->m_data += sizeof(struct ieee80211_frame);
  464                 frm = mtod(m, u_int8_t *);
  465 
  466                 capinfo = 0;
  467                 if (ic->ic_opmode == IEEE80211_M_IBSS)
  468                         capinfo |= IEEE80211_CAPINFO_IBSS;
  469                 else            /* IEEE80211_M_STA */
  470                         capinfo |= IEEE80211_CAPINFO_ESS;
  471                 if (ic->ic_flags & IEEE80211_F_WEPON)
  472                         capinfo |= IEEE80211_CAPINFO_PRIVACY;
  473                 /*
  474                  * NB: Some 11a AP's reject the request when
  475                  *     short premable is set.
  476                  */
  477                 if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
  478                     IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
  479                         capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
  480                 if (ic->ic_flags & IEEE80211_F_SHSLOT)
  481                         capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
  482                 *(u_int16_t *)frm = htole16(capinfo);
  483                 frm += 2;
  484 
  485                 *(u_int16_t *)frm = htole16(ic->ic_lintval);
  486                 frm += 2;
  487 
  488                 if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
  489                         IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
  490                         frm += IEEE80211_ADDR_LEN;
  491                 }
  492 
  493                 frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
  494                 frm = ieee80211_add_rates(frm, &ni->ni_rates);
  495                 frm = ieee80211_add_xrates(frm, &ni->ni_rates);
  496                 m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  497 
  498                 timer = IEEE80211_TRANS_WAIT;
  499                 break;
  500 
  501         case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
  502         case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
  503                 /*
  504                  * asreq frame format
  505                  *      [2] capability information
  506                  *      [2] status
  507                  *      [2] association ID
  508                  *      [tlv] supported rates
  509                  *      [tlv] extended supported rates
  510                  */
  511                 m = ieee80211_getmbuf(M_DONTWAIT, MT_DATA,
  512                          sizeof(capinfo)
  513                        + sizeof(u_int16_t)
  514                        + sizeof(u_int16_t)
  515                        + 2 + IEEE80211_RATE_SIZE
  516                        + 2 + (IEEE80211_RATE_MAXSIZE - IEEE80211_RATE_SIZE));
  517                 if (m == NULL)
  518                         senderr(ENOMEM, is_tx_nombuf);
  519                 m->m_data += sizeof(struct ieee80211_frame);
  520                 frm = mtod(m, u_int8_t *);
  521 
  522                 capinfo = IEEE80211_CAPINFO_ESS;
  523                 if (ic->ic_flags & IEEE80211_F_WEPON)
  524                         capinfo |= IEEE80211_CAPINFO_PRIVACY;
  525                 if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
  526                     IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
  527                         capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
  528                 *(u_int16_t *)frm = htole16(capinfo);
  529                 frm += 2;
  530 
  531                 *(u_int16_t *)frm = htole16(arg);       /* status */
  532                 frm += 2;
  533 
  534                 if (arg == IEEE80211_STATUS_SUCCESS)
  535                         *(u_int16_t *)frm = htole16(ni->ni_associd);
  536                 frm += 2;
  537 
  538                 frm = ieee80211_add_rates(frm, &ni->ni_rates);
  539                 frm = ieee80211_add_xrates(frm, &ni->ni_rates);
  540                 m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  541                 break;
  542 
  543         case IEEE80211_FC0_SUBTYPE_DISASSOC:
  544                 if (ifp->if_flags & IFF_DEBUG)
  545                         if_printf(ifp, "station %s disassociate (reason %d)\n",
  546                             ether_sprintf(ni->ni_macaddr), arg);
  547                 MGETHDR(m, M_DONTWAIT, MT_DATA);
  548                 if (m == NULL)
  549                         senderr(ENOMEM, is_tx_nombuf);
  550                 MH_ALIGN(m, 2);
  551                 m->m_pkthdr.len = m->m_len = 2;
  552                 *mtod(m, u_int16_t *) = htole16(arg);   /* reason */
  553                 break;
  554 
  555         default:
  556                 IEEE80211_DPRINTF(("%s: invalid mgmt frame type %u\n",
  557                         __func__, type));
  558                 senderr(EINVAL, is_tx_unknownmgt);
  559                 /* NOTREACHED */
  560         }
  561 
  562         ret = ieee80211_mgmt_output(ifp, ni, m, type);
  563         if (ret == 0) {
  564                 if (timer)
  565                         ic->ic_mgt_timer = timer;
  566         } else {
  567 bad:
  568                 if (ni != ic->ic_bss)           /* remove ref we added */
  569                         ieee80211_free_node(ic, ni);
  570         }
  571         return ret;
  572 #undef senderr
  573 }

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