FreeBSD/Linux Kernel Cross Reference
sys/net80211/ieee80211_output.c

     /*      $OpenBSD: ieee80211_output.c,v 1.137 2022/03/14 15:07:24 stsp Exp $     */
     /*      $NetBSD: ieee80211_output.c,v 1.13 2004/05/31 11:02:55 dyoung Exp $     */
     
     /*-
      * Copyright (c) 2001 Atsushi Onoe
      * Copyright (c) 2002, 2003 Sam Leffler, Errno Consulting
      * Copyright (c) 2007-2009 Damien Bergamini
      * All rights reserved.
      *
     * Redistribution and use in source and binary forms, with or without
     * modification, are permitted provided that the following conditions
     * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     * 3. The name of the author may not be used to endorse or promote products
     *    derived from this software without specific prior written permission.
     *
     * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
     * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
     * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
     * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
     * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
     * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
     * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include "bpfilter.h"
    #include "vlan.h"
    
    #include <sys/param.h>
    #include <sys/systm.h>
    #include <sys/mbuf.h>
    #include <sys/kernel.h>
    #include <sys/socket.h>
    #include <sys/sockio.h>
    #include <sys/endian.h>
    #include <sys/errno.h>
    #include <sys/sysctl.h>
    
    #include <net/if.h>
    #include <net/if_dl.h>
    #include <net/if_media.h>
    #include <net/if_llc.h>
    #include <net/bpf.h>
    
    #include <netinet/in.h>
    #include <netinet/if_ether.h>
    #include <netinet/ip.h>
    #ifdef INET6
    #include <netinet/ip6.h>
    #endif
    
    #if NVLAN > 0
    #include <net/if_vlan_var.h>
    #endif
    
    #include <net80211/ieee80211_var.h>
    #include <net80211/ieee80211_priv.h>
    
    int     ieee80211_mgmt_output(struct ifnet *, struct ieee80211_node *,
                struct mbuf *, int);
    int     ieee80211_can_use_ampdu(struct ieee80211com *,
                struct ieee80211_node *);
    u_int8_t *ieee80211_add_rsn_body(u_int8_t *, struct ieee80211com *,
                const struct ieee80211_node *, int);
    struct  mbuf *ieee80211_getmgmt(int, int, u_int);
    struct  mbuf *ieee80211_get_probe_req(struct ieee80211com *,
                struct ieee80211_node *);
    #ifndef IEEE80211_STA_ONLY
    struct  mbuf *ieee80211_get_probe_resp(struct ieee80211com *);
    #endif
    struct  mbuf *ieee80211_get_auth(struct ieee80211com *,
                struct ieee80211_node *, u_int16_t, u_int16_t);
    struct  mbuf *ieee80211_get_deauth(struct ieee80211com *,
                struct ieee80211_node *, u_int16_t);
    struct  mbuf *ieee80211_get_assoc_req(struct ieee80211com *,
                struct ieee80211_node *, int);
    #ifndef IEEE80211_STA_ONLY
    struct  mbuf *ieee80211_get_assoc_resp(struct ieee80211com *,
                struct ieee80211_node *, u_int16_t);
    #endif
    struct  mbuf *ieee80211_get_disassoc(struct ieee80211com *,
                struct ieee80211_node *, u_int16_t);
    struct  mbuf *ieee80211_get_addba_req(struct ieee80211com *,
                struct ieee80211_node *, u_int8_t);
    struct  mbuf *ieee80211_get_addba_resp(struct ieee80211com *,
                struct ieee80211_node *, u_int8_t, u_int8_t, u_int16_t);
    struct  mbuf *ieee80211_get_delba(struct ieee80211com *,
                struct ieee80211_node *, u_int8_t, u_int8_t, u_int16_t);
    uint8_t *ieee80211_add_wme_info(uint8_t *, struct ieee80211com *);
    #ifndef IEEE80211_STA_ONLY
    uint8_t *ieee80211_add_wme_param(uint8_t *, struct ieee80211com *);
    #endif
   struct  mbuf *ieee80211_get_sa_query(struct ieee80211com *,
               struct ieee80211_node *, u_int8_t);
   struct  mbuf *ieee80211_get_action(struct ieee80211com *,
               struct ieee80211_node *, u_int8_t, u_int8_t, int);
   
   /*
    * IEEE 802.11 output routine. Normally this will directly call the
    * Ethernet output routine because 802.11 encapsulation is called
    * later by the driver. This function can be used to send raw frames
    * if the mbuf has been tagged with a 802.11 data link type.
    */
   int
   ieee80211_output(struct ifnet *ifp, struct mbuf *m, struct sockaddr *dst,
       struct rtentry *rt)
   {
           struct ieee80211_frame *wh;
           struct m_tag *mtag;
           int error = 0;
   
           /* Interface has to be up and running */
           if ((ifp->if_flags & (IFF_UP | IFF_RUNNING)) !=
               (IFF_UP | IFF_RUNNING)) {
                   error = ENETDOWN;
                   goto bad;
           }
   
           /* Try to get the DLT from a mbuf tag */
           if ((mtag = m_tag_find(m, PACKET_TAG_DLT, NULL)) != NULL) {
                   struct ieee80211com *ic = (void *)ifp;
                   u_int dlt = *(u_int *)(mtag + 1);
   
                   /* Fallback to ethernet for non-802.11 linktypes */
                   if (!(dlt == DLT_IEEE802_11 || dlt == DLT_IEEE802_11_RADIO))
                           goto fallback;
   
                   if (m->m_pkthdr.len < sizeof(struct ieee80211_frame_min))
                           return (EINVAL);
                   wh = mtod(m, struct ieee80211_frame *);
                   if ((wh->i_fc[0] & IEEE80211_FC0_VERSION_MASK) !=
                       IEEE80211_FC0_VERSION_0)
                           return (EINVAL);
                   if (!(ic->ic_caps & IEEE80211_C_RAWCTL) &&
                       (wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) ==
                       IEEE80211_FC0_TYPE_CTL)
                           return (EINVAL);
   
                   return (if_enqueue(ifp, m));
           }
   
    fallback:
           return (ether_output(ifp, m, dst, rt));
   
    bad:
           m_freem(m);
           return (error);
   }
   
   const char *
   ieee80211_action_name(struct ieee80211_frame *wh)
   {
           const u_int8_t *frm = (const uint8_t *)&wh[1];
           const char *categ_ba_name[3] = { "addba_req", "addba_resp", "delba" };
   
           if (frm[0] == IEEE80211_CATEG_BA && frm[1] < nitems(categ_ba_name))
                   return categ_ba_name[frm[1]];
   
           return "action";
   }
   
   /*
    * Send a management frame to the specified node.  The node pointer
    * must have a reference as the pointer will be passed to the driver
    * and potentially held for a long time.  If the frame is successfully
    * dispatched to the driver, then it is responsible for freeing the
    * reference (and potentially free'ing up any associated storage).
    */
   int
   ieee80211_mgmt_output(struct ifnet *ifp, struct ieee80211_node *ni,
       struct mbuf *m, int type)
   {
           struct ieee80211com *ic = (void *)ifp;
           struct ieee80211_frame *wh;
   
           if (ni == NULL)
                   panic("null node");
           ni->ni_inact = 0;
   
           /*
            * We want to pass the node down to the driver's start
            * routine.  We could stick this in an m_tag and tack that
            * on to the mbuf.  However that's rather expensive to do
            * for every frame so instead we stuff it in a special pkthdr
            * field.
            */
           M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
           if (m == NULL)
                   return ENOMEM;
           m->m_pkthdr.ph_cookie = ni;
   
           wh = mtod(m, struct ieee80211_frame *);
           wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT | type;
           wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
           *(u_int16_t *)&wh->i_dur[0] = 0;
           *(u_int16_t *)&wh->i_seq[0] =
               htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
           ni->ni_txseq = (ni->ni_txseq + 1) & 0xfff;
           IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_macaddr);
           IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
           IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
   
           /* check if protection is required for this mgmt frame */
           if ((ic->ic_caps & IEEE80211_C_MFP) &&
               (type == IEEE80211_FC0_SUBTYPE_DISASSOC ||
                type == IEEE80211_FC0_SUBTYPE_DEAUTH ||
                type == IEEE80211_FC0_SUBTYPE_ACTION)) {
                   /*
                    * Hack: we should not set the Protected bit in outgoing
                    * group management frames, however it is used as an
                    * indication to the drivers that they must encrypt the
                    * frame.  Drivers should clear this bit from group
                    * management frames (software crypto code will do it).
                    * XXX could use an mbuf flag..
                    */
                   if (IEEE80211_IS_MULTICAST(wh->i_addr1) ||
                       (ni->ni_flags & IEEE80211_NODE_TXMGMTPROT))
                           wh->i_fc[1] |= IEEE80211_FC1_PROTECTED;
           }
   
           if (ifp->if_flags & IFF_DEBUG) {
                   /* avoid to print too many frames */
                   if (
   #ifndef IEEE80211_STA_ONLY
                       ic->ic_opmode == IEEE80211_M_IBSS ||
   #endif
   #ifdef IEEE80211_DEBUG
                       ieee80211_debug > 1 ||
   #endif
                       (type & IEEE80211_FC0_SUBTYPE_MASK) !=
                       IEEE80211_FC0_SUBTYPE_PROBE_RESP) {
                           const char *subtype_name;
                           if ((type & IEEE80211_FC0_SUBTYPE_MASK) ==
                               IEEE80211_FC0_SUBTYPE_ACTION)
                                   subtype_name = ieee80211_action_name(wh);
                           else
                                   subtype_name = ieee80211_mgt_subtype_name[
                                       (type & IEEE80211_FC0_SUBTYPE_MASK) >>
                                       IEEE80211_FC0_SUBTYPE_SHIFT];
                           printf("%s: sending %s to %s on channel %u mode %s\n",
                               ifp->if_xname, subtype_name,
                               ether_sprintf(ni->ni_macaddr),
                               ieee80211_chan2ieee(ic, ni->ni_chan),
                               ieee80211_phymode_name[ic->ic_curmode]);
                   }
           }
   
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_HOSTAP &&
               ieee80211_pwrsave(ic, m, ni) != 0)
                   return 0;
   #endif
           mq_enqueue(&ic->ic_mgtq, m);
           ifp->if_timer = 1;
           if_start(ifp);
           return 0;
   }
   
   /*-
    * EDCA tables are computed using the following formulas:
    *
    * 1) EDCATable (non-AP QSTA)
    *
    * AC     CWmin            CWmax           AIFSN  TXOP limit(ms)
    * -------------------------------------------------------------
    * AC_BK  aCWmin           aCWmax          7      0
    * AC_BE  aCWmin           aCWmax          3      0
    * AC_VI  (aCWmin+1)/2-1   aCWmin          2      agn=3.008 b=6.016 others=0
    * AC_VO  (aCWmin+1)/4-1   (aCWmin+1)/2-1  2      agn=1.504 b=3.264 others=0
    *
    * 2) QAPEDCATable (QAP)
    *
    * AC     CWmin            CWmax           AIFSN  TXOP limit(ms)
    * -------------------------------------------------------------
    * AC_BK  aCWmin           aCWmax          7      0
    * AC_BE  aCWmin           4*(aCWmin+1)-1  3      0
    * AC_VI  (aCWmin+1)/2-1   aCWmin          1      agn=3.008 b=6.016 others=0
    * AC_VO  (aCWmin+1)/4-1   (aCWmin+1)/2-1  1      agn=1.504 b=3.264 others=0
    *
    * and the following aCWmin/aCWmax values:
    *
    * PHY          aCWmin  aCWmax
    * ---------------------------
    * 11A          15      1023
    * 11B          31      1023
    * 11G          15*     1023    (*) aCWmin(1)
    * 11N          15      1023
    */
   const struct ieee80211_edca_ac_params
       ieee80211_edca_table[IEEE80211_MODE_MAX][EDCA_NUM_AC] = {
           [IEEE80211_MODE_11B] = {
                   [EDCA_AC_BK] = { 5, 10, 7,   0 },
                   [EDCA_AC_BE] = { 5, 10, 3,   0 },
                   [EDCA_AC_VI] = { 4,  5, 2, 188 },
                   [EDCA_AC_VO] = { 3,  4, 2, 102 }
           },
           [IEEE80211_MODE_11A] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4, 10, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 2,  94 },
                   [EDCA_AC_VO] = { 2,  3, 2,  47 }
           },
           [IEEE80211_MODE_11G] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4, 10, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 2,  94 },
                   [EDCA_AC_VO] = { 2,  3, 2,  47 }
           },
           [IEEE80211_MODE_11N] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4, 10, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 2,  94 },
                   [EDCA_AC_VO] = { 2,  3, 2,  47 }
           },
           [IEEE80211_MODE_11AC] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4, 10, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 2,  94 },
                   [EDCA_AC_VO] = { 2,  3, 2,  47 }
           },
   };
   
   #ifndef IEEE80211_STA_ONLY
   const struct ieee80211_edca_ac_params
       ieee80211_qap_edca_table[IEEE80211_MODE_MAX][EDCA_NUM_AC] = {
           [IEEE80211_MODE_11B] = {
                   [EDCA_AC_BK] = { 5, 10, 7,   0 },
                   [EDCA_AC_BE] = { 5,  7, 3,   0 },
                   [EDCA_AC_VI] = { 4,  5, 1, 188 },
                   [EDCA_AC_VO] = { 3,  4, 1, 102 }
           },
           [IEEE80211_MODE_11A] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4,  6, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 1,  94 },
                   [EDCA_AC_VO] = { 2,  3, 1,  47 }
           },
           [IEEE80211_MODE_11G] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4,  6, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 1,  94 },
                   [EDCA_AC_VO] = { 2,  3, 1,  47 }
           },
           [IEEE80211_MODE_11N] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4,  6, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 1,  94 },
                   [EDCA_AC_VO] = { 2,  3, 1,  47 }
           },
           [IEEE80211_MODE_11AC] = {
                   [EDCA_AC_BK] = { 4, 10, 7,   0 },
                   [EDCA_AC_BE] = { 4,  6, 3,   0 },
                   [EDCA_AC_VI] = { 3,  4, 1,  94 },
                   [EDCA_AC_VO] = { 2,  3, 1,  47 }
           },
   };
   #endif  /* IEEE80211_STA_ONLY */
   
   /*
    * Return the EDCA Access Category to be used for transmitting a frame with
    * user-priority `up'.
    */
   enum ieee80211_edca_ac
   ieee80211_up_to_ac(struct ieee80211com *ic, int up)
   {
           /* see Table 9-1 */
           static const enum ieee80211_edca_ac up_to_ac[] = {
                   EDCA_AC_BE,     /* BE */
                   EDCA_AC_BK,     /* BK */
                   EDCA_AC_BK,     /* -- */
                   EDCA_AC_BE,     /* EE */
                   EDCA_AC_VI,     /* CL */
                   EDCA_AC_VI,     /* VI */
                   EDCA_AC_VO,     /* VO */
                   EDCA_AC_VO      /* NC */
           };
           enum ieee80211_edca_ac ac;
   
           ac = (up <= 7) ? up_to_ac[up] : EDCA_AC_BE;
   
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_HOSTAP)
                   return ac;
   #endif
           /*
            * We do not support the admission control procedure defined in
            * IEEE Std 802.11-2012 section 9.19.4.2.3. The spec says that
            * non-AP QSTAs that don't support this procedure shall use EDCA
            * parameters of a lower priority AC that does not require
            * admission control.
            */
           while (ac != EDCA_AC_BK && ic->ic_edca_ac[ac].ac_acm) {
                   switch (ac) {
                   case EDCA_AC_BK:
                           /* can't get there */
                           break;
                   case EDCA_AC_BE:
                           /* BE shouldn't require admission control */
                           ac = EDCA_AC_BK;
                           break;
                   case EDCA_AC_VI:
                           ac = EDCA_AC_BE;
                           break;
                   case EDCA_AC_VO:
                           ac = EDCA_AC_VI;
                           break;
                   }
           }
           return ac;
   }
   
   /*
    * Get mbuf's user-priority: if mbuf is not VLAN tagged, select user-priority
    * based on the DSCP (Differentiated Services Codepoint) field.
    */
   int
   ieee80211_classify(struct ieee80211com *ic, struct mbuf *m)
   {
           struct ether_header eh;
           u_int8_t ds_field;
   #if NVLAN > 0
           if (m->m_flags & M_VLANTAG)     /* use VLAN 802.1D user-priority */
                   return EVL_PRIOFTAG(m->m_pkthdr.ether_vtag);
   #endif
           m_copydata(m, 0, sizeof(eh), (caddr_t)&eh);
           if (eh.ether_type == htons(ETHERTYPE_IP)) {
                   struct ip ip;
                   m_copydata(m, sizeof(eh), sizeof(ip), (caddr_t)&ip);
                   if (ip.ip_v != 4)
                           return 0;
                   ds_field = ip.ip_tos;
           }
   #ifdef INET6
           else if (eh.ether_type == htons(ETHERTYPE_IPV6)) {
                   struct ip6_hdr ip6;
                   u_int32_t flowlabel;
                   m_copydata(m, sizeof(eh), sizeof(ip6), (caddr_t)&ip6);
                   flowlabel = ntohl(ip6.ip6_flow);
                   if ((flowlabel >> 28) != 6)
                           return 0;
                   ds_field = (flowlabel >> 20) & 0xff;
           }
   #endif  /* INET6 */
           else    /* neither IPv4 nor IPv6 */
                   return 0;
   
           /*
            * Map Differentiated Services Codepoint field (see RFC2474).
            * Preserves backward compatibility with IP Precedence field.
            */
           switch (ds_field & 0xfc) {
           case IPTOS_PREC_PRIORITY:
                   return EDCA_AC_VI;
           case IPTOS_PREC_IMMEDIATE:
                   return EDCA_AC_BK;
           case IPTOS_PREC_FLASH:
           case IPTOS_PREC_FLASHOVERRIDE:
           case IPTOS_PREC_CRITIC_ECP:
           case IPTOS_PREC_INTERNETCONTROL:
           case IPTOS_PREC_NETCONTROL:
                   return EDCA_AC_VO;
           default:
                   return EDCA_AC_BE;
           }
   }
   
   int
   ieee80211_can_use_ampdu(struct ieee80211com *ic, struct ieee80211_node *ni)
   {
           return (ni->ni_flags & IEEE80211_NODE_HT) &&
               (ic->ic_caps & IEEE80211_C_TX_AMPDU) &&
               !(ic->ic_opmode == IEEE80211_M_STA && ni != ic->ic_bss) &&
               /*
                * Don't use A-MPDU on non-encrypted networks. There are devices
                * with buggy firmware which allow an attacker to inject 802.11
                * frames into a wifi network by embedding rogue A-MPDU subframes
                * in an arbitrary data payload (e.g. PNG images) which may end
                * up appearing as actual frames after de-aggregation by a buggy
                * device; see https://github.com/rpp0/aggr-inject for details.
                * WPA2 prevents this injection attack since the attacker would
                * need to inject frames which get decrypted correctly.
                */
               ((ic->ic_flags & IEEE80211_F_RSNON) &&
                 (ni->ni_rsnprotos & IEEE80211_PROTO_RSN));
   }
   
   void
   ieee80211_tx_compressed_bar(struct ieee80211com *ic, struct ieee80211_node *ni,
       int tid, uint16_t ssn)
   {
           struct ifnet *ifp = &ic->ic_if;
           struct mbuf *m;
   
           m = ieee80211_get_compressed_bar(ic, ni, tid, ssn);
           if (m == NULL)
                   return;
   
           ieee80211_ref_node(ni);
           if (mq_enqueue(&ic->ic_mgtq, m) == 0)
                   if_start(ifp);
           else
                   ieee80211_release_node(ic, ni);
   }
   
   /*
    * Encapsulate an outbound data frame.  The mbuf chain is updated and
    * a reference to the destination node is returned.  If an error is
    * encountered NULL is returned and the node reference will also be NULL.
    *
    * NB: The caller is responsible for free'ing a returned node reference.
    *     The convention is ic_bss is not reference counted; the caller must
    *     maintain that.
    */
   struct mbuf *
   ieee80211_encap(struct ifnet *ifp, struct mbuf *m, struct ieee80211_node **pni)
   {
           struct ieee80211com *ic = (void *)ifp;
           struct ether_header eh;
           struct ieee80211_frame *wh;
           struct ieee80211_node *ni = NULL;
           struct llc *llc;
           struct m_tag *mtag;
           u_int8_t *addr;
           u_int dlt, hdrlen;
           int addqos, tid;
   
           /* Handle raw frames if mbuf is tagged as 802.11 */
           if ((mtag = m_tag_find(m, PACKET_TAG_DLT, NULL)) != NULL) {
                   dlt = *(u_int *)(mtag + 1);
   
                   if (!(dlt == DLT_IEEE802_11 || dlt == DLT_IEEE802_11_RADIO))
                           goto fallback;
   
                   wh = mtod(m, struct ieee80211_frame *);
                   switch (wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) {
                   case IEEE80211_FC1_DIR_NODS:
                   case IEEE80211_FC1_DIR_FROMDS:
                           addr = wh->i_addr1;
                           break;
                   case IEEE80211_FC1_DIR_DSTODS:
                   case IEEE80211_FC1_DIR_TODS:
                           addr = wh->i_addr3;
                           break;
                   default:
                           goto bad;
                   }
   
                   ni = ieee80211_find_txnode(ic, addr);
                   if (ni == NULL)
                           ni = ieee80211_ref_node(ic->ic_bss);
                   if (ni == NULL) {
                           printf("%s: no node for dst %s, "
                               "discard raw tx frame\n", ifp->if_xname,
                               ether_sprintf(addr));
                           ic->ic_stats.is_tx_nonode++;
                           goto bad;
                   }
                   ni->ni_inact = 0;
   
                   *pni = ni;
                   return (m);
           }
   
    fallback:
           if (m->m_len < sizeof(struct ether_header)) {
                   m = m_pullup(m, sizeof(struct ether_header));
                   if (m == NULL) {
                           ic->ic_stats.is_tx_nombuf++;
                           goto bad;
                   }
           }
           memcpy(&eh, mtod(m, caddr_t), sizeof(struct ether_header));
   
           ni = ieee80211_find_txnode(ic, eh.ether_dhost);
           if (ni == NULL) {
                   DPRINTF(("no node for dst %s, discard frame\n",
                       ether_sprintf(eh.ether_dhost)));
                   ic->ic_stats.is_tx_nonode++;
                   goto bad;
           }
   
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_HOSTAP && ni != ic->ic_bss &&
               ni->ni_state != IEEE80211_STA_ASSOC) {
                   ic->ic_stats.is_tx_nonode++;
                   goto bad;
           }
   #endif
   
           if ((ic->ic_flags & IEEE80211_F_RSNON) &&
               !ni->ni_port_valid &&
               eh.ether_type != htons(ETHERTYPE_EAPOL)) {
                   DPRINTF(("port not valid: %s\n",
                       ether_sprintf(eh.ether_dhost)));
                   ic->ic_stats.is_tx_noauth++;
                   goto bad;
           }
   
           if ((ic->ic_flags & IEEE80211_F_COUNTERM) &&
               ni->ni_rsncipher == IEEE80211_CIPHER_TKIP)
                   /* XXX TKIP countermeasures! */;
   
           ni->ni_inact = 0;
   
           if ((ic->ic_flags & IEEE80211_F_QOS) &&
               (ni->ni_flags & IEEE80211_NODE_QOS) &&
               /* do not QoS-encapsulate EAPOL frames */
               eh.ether_type != htons(ETHERTYPE_EAPOL)) {
                   struct ieee80211_tx_ba *ba;
                   tid = ieee80211_classify(ic, m);
                   ba = &ni->ni_tx_ba[tid];
                   /* We use QoS data frames for aggregation only. */
                   if (ba->ba_state != IEEE80211_BA_AGREED) {
                           hdrlen = sizeof(struct ieee80211_frame);
                           addqos = 0;
                           if (ieee80211_can_use_ampdu(ic, ni))
                                   ieee80211_node_trigger_addba_req(ni, tid);
                   } else {
                           hdrlen = sizeof(struct ieee80211_qosframe);
                           addqos = 1;
                   }
           } else {
                   hdrlen = sizeof(struct ieee80211_frame);
                   addqos = 0;
           }
           m_adj(m, sizeof(struct ether_header) - LLC_SNAPFRAMELEN);
           llc = mtod(m, struct llc *);
           llc->llc_dsap = llc->llc_ssap = LLC_SNAP_LSAP;
           llc->llc_control = LLC_UI;
           llc->llc_snap.org_code[0] = 0;
           llc->llc_snap.org_code[1] = 0;
           llc->llc_snap.org_code[2] = 0;
           llc->llc_snap.ether_type = eh.ether_type;
           M_PREPEND(m, hdrlen, M_DONTWAIT);
           if (m == NULL) {
                   ic->ic_stats.is_tx_nombuf++;
                   goto bad;
           }
           wh = mtod(m, struct ieee80211_frame *);
           wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_DATA;
           *(u_int16_t *)&wh->i_dur[0] = 0;
           if (addqos) {
                   struct ieee80211_qosframe *qwh =
                       (struct ieee80211_qosframe *)wh;
                   u_int16_t qos = tid;
   
                   if (ic->ic_tid_noack & (1 << tid))
                           qos |= IEEE80211_QOS_ACK_POLICY_NOACK;
                   else {
                           /* Use HT immediate block-ack. */
                           qos |= IEEE80211_QOS_ACK_POLICY_NORMAL;
                   }
                   qwh->i_fc[0] |= IEEE80211_FC0_SUBTYPE_QOS;
                   *(u_int16_t *)qwh->i_qos = htole16(qos);
                   *(u_int16_t *)qwh->i_seq =
                       htole16(ni->ni_qos_txseqs[tid] << IEEE80211_SEQ_SEQ_SHIFT);
                   ni->ni_qos_txseqs[tid] = (ni->ni_qos_txseqs[tid] + 1) & 0xfff;
           } else {
                   *(u_int16_t *)&wh->i_seq[0] =
                       htole16(ni->ni_txseq << IEEE80211_SEQ_SEQ_SHIFT);
                   ni->ni_txseq = (ni->ni_txseq + 1) & 0xfff;
           }
           switch (ic->ic_opmode) {
           case IEEE80211_M_STA:
                   wh->i_fc[1] = IEEE80211_FC1_DIR_TODS;
                   IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_bssid);
                   IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
                   IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_dhost);
                   break;
   #ifndef IEEE80211_STA_ONLY
           case IEEE80211_M_IBSS:
           case IEEE80211_M_AHDEMO:
                   wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
                   IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
                   IEEE80211_ADDR_COPY(wh->i_addr2, eh.ether_shost);
                   IEEE80211_ADDR_COPY(wh->i_addr3, ic->ic_bss->ni_bssid);
                   break;
           case IEEE80211_M_HOSTAP:
                   wh->i_fc[1] = IEEE80211_FC1_DIR_FROMDS;
                   IEEE80211_ADDR_COPY(wh->i_addr1, eh.ether_dhost);
                   IEEE80211_ADDR_COPY(wh->i_addr2, ni->ni_bssid);
                   IEEE80211_ADDR_COPY(wh->i_addr3, eh.ether_shost);
                   break;
   #endif
           default:
                   /* should not get there */
                   goto bad;
           }
   
           if ((ic->ic_flags & IEEE80211_F_WEPON) ||
               ((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ni->ni_flags & IEEE80211_NODE_TXPROT)))
                   wh->i_fc[1] |= IEEE80211_FC1_PROTECTED;
   
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_HOSTAP &&
               ieee80211_pwrsave(ic, m, ni) != 0) {
                   *pni = NULL;
                   return NULL;
           }
   #endif
           *pni = ni;
           return m;
   bad:
           m_freem(m);
           if (ni != NULL)
                   ieee80211_release_node(ic, ni);
           *pni = NULL;
           return NULL;
   }
   
   /*
    * Add a Capability Information field to a frame (see 7.3.1.4).
    */
   u_int8_t *
   ieee80211_add_capinfo(u_int8_t *frm, struct ieee80211com *ic,
       const struct ieee80211_node *ni)
   {
           u_int16_t capinfo;
   
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_IBSS)
                   capinfo = IEEE80211_CAPINFO_IBSS;
           else if (ic->ic_opmode == IEEE80211_M_HOSTAP)
                   capinfo = IEEE80211_CAPINFO_ESS;
           else
   #endif
                   capinfo = 0;
   #ifndef IEEE80211_STA_ONLY
           if (ic->ic_opmode == IEEE80211_M_HOSTAP &&
               (ic->ic_flags & (IEEE80211_F_WEPON | IEEE80211_F_RSNON)))
                   capinfo |= IEEE80211_CAPINFO_PRIVACY;
   #endif
           /* NB: some 11a AP's reject the request when short preamble is set */
           if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
               IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
                   capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
           if (ic->ic_flags & IEEE80211_F_SHSLOT)
                   capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
           LE_WRITE_2(frm, capinfo);
           return frm + 2;
   }
   
   /*
    * Add an SSID element to a frame (see 7.3.2.1).
    */
   u_int8_t *
   ieee80211_add_ssid(u_int8_t *frm, const u_int8_t *ssid, u_int len)
   {
           *frm++ = IEEE80211_ELEMID_SSID;
           *frm++ = len;
           memcpy(frm, ssid, len);
           return frm + len;
   }
   
   /*
    * Add a supported rates element to a frame (see 7.3.2.2).
    */
   u_int8_t *
   ieee80211_add_rates(u_int8_t *frm, const struct ieee80211_rateset *rs)
   {
           int nrates;
   
           *frm++ = IEEE80211_ELEMID_RATES;
           nrates = min(rs->rs_nrates, IEEE80211_RATE_SIZE);
           *frm++ = nrates;
           memcpy(frm, rs->rs_rates, nrates);
           return frm + nrates;
   }
   
   #ifndef IEEE80211_STA_ONLY
   /*
    * Add a DS Parameter Set element to a frame (see 7.3.2.4).
    */
   u_int8_t *
   ieee80211_add_ds_params(u_int8_t *frm, struct ieee80211com *ic,
       const struct ieee80211_node *ni)
   {
           *frm++ = IEEE80211_ELEMID_DSPARMS;
           *frm++ = 1;
           *frm++ = ieee80211_chan2ieee(ic, ni->ni_chan);
           return frm;
   }
   
   /*
    * Add a TIM element to a frame (see 7.3.2.6 and Annex L).
    */
   u_int8_t *
   ieee80211_add_tim(u_int8_t *frm, struct ieee80211com *ic)
   {
           u_int i, offset = 0, len;
   
           /* find first non-zero octet in the virtual bit map */
           for (i = 0; i < ic->ic_tim_len && ic->ic_tim_bitmap[i] == 0; i++);
   
           /* clear the lsb as it is reserved for the broadcast indication bit */
           if (i < ic->ic_tim_len)
                   offset = i & ~1;
   
           /* find last non-zero octet in the virtual bit map */
           for (i = ic->ic_tim_len - 1; i > 0 && ic->ic_tim_bitmap[i] == 0; i--);
   
           len = i - offset + 1;
   
           *frm++ = IEEE80211_ELEMID_TIM;
           *frm++ = len + 3;               /* length */
           *frm++ = ic->ic_dtim_count;     /* DTIM count */
           *frm++ = ic->ic_dtim_period;    /* DTIM period */
   
           /* Bitmap Control */
           *frm = offset;
           /* set broadcast/multicast indication bit if necessary */
           if (ic->ic_dtim_count == 0 && ic->ic_tim_mcast_pending)
                   *frm |= 0x01;
           frm++;
   
           /* Partial Virtual Bitmap */
           memcpy(frm, &ic->ic_tim_bitmap[offset], len);
           return frm + len;
   }
   
   /*
    * Add an IBSS Parameter Set element to a frame (see 7.3.2.7).
    */
   u_int8_t *
   ieee80211_add_ibss_params(u_int8_t *frm, const struct ieee80211_node *ni)
   {
           *frm++ = IEEE80211_ELEMID_IBSSPARMS;
           *frm++ = 2;
           LE_WRITE_2(frm, 0);     /* TODO: ATIM window */
           return frm + 2;
   }
   
   /*
    * Add an EDCA Parameter Set element to a frame (see 7.3.2.29).
    */
   u_int8_t *
   ieee80211_add_edca_params(u_int8_t *frm, struct ieee80211com *ic)
   {
           const struct ieee80211_edca_ac_params *edca;
           int aci;
   
           *frm++ = IEEE80211_ELEMID_EDCAPARMS;
           *frm++ = 18;    /* length */
           *frm++ = 0;     /* QoS Info */
           *frm++ = 0;     /* reserved */
   
           /* setup AC Parameter Records */
           edca = ieee80211_edca_table[ic->ic_curmode];
           for (aci = 0; aci < EDCA_NUM_AC; aci++) {
                   const struct ieee80211_edca_ac_params *ac = &edca[aci];
   
                   *frm++ = (aci << 5) | ((ac->ac_acm & 0x1) << 4) |
                            (ac->ac_aifsn & 0xf);
                   *frm++ = (ac->ac_ecwmax << 4) |
                            (ac->ac_ecwmin & 0xf);
                   LE_WRITE_2(frm, ac->ac_txoplimit); frm += 2;
           }
           return frm;
   }
   
   /*
    * Add an ERP element to a frame (see 7.3.2.13).
    */
   u_int8_t *
   ieee80211_add_erp(u_int8_t *frm, struct ieee80211com *ic)
   {
           u_int8_t erp;
           int nonerpsta = 0;
   
           *frm++ = IEEE80211_ELEMID_ERP;
           *frm++ = 1;
           erp = 0;
           /*
            * The NonERP_Present bit shall be set to 1 when a NonERP STA
            * is associated with the BSS.
            */
           ieee80211_iterate_nodes(ic, ieee80211_count_nonerpsta, &nonerpsta);
           if (nonerpsta != 0)
                   erp |= IEEE80211_ERP_NON_ERP_PRESENT;
           /*
            * If one or more NonERP STAs are associated in the BSS, the
            * Use_Protection bit shall be set to 1 in transmitted ERP
            * Information Elements.
            */
           if (ic->ic_flags & IEEE80211_F_USEPROT)
                   erp |= IEEE80211_ERP_USE_PROTECTION;
           /*
            * The Barker_Preamble_Mode bit shall be set to 1 by the ERP
            * Information Element sender if one or more associated NonERP
            * STAs are not short preamble capable.
            */
           if (!(ic->ic_flags & IEEE80211_F_SHPREAMBLE))
                   erp |= IEEE80211_ERP_BARKER_MODE;
           *frm++ = erp;
           return frm;
   }
   #endif  /* IEEE80211_STA_ONLY */
   
   /*
    * Add a QoS Capability element to a frame (see 7.3.2.35).
    */
   u_int8_t *
   ieee80211_add_qos_capability(u_int8_t *frm, struct ieee80211com *ic)
   {
           *frm++ = IEEE80211_ELEMID_QOS_CAP;
           *frm++ = 1;
           *frm++ = 0;     /* QoS Info */
           return frm;
   }
   
   /*
    * Add a Wifi-Alliance WME (aka WMM) info element to a frame.
    * WME is a requirement for Wifi-Alliance compliance and some
    * 11n APs will not negotiate HT if this element is missing.
    */
   uint8_t *
   ieee80211_add_wme_info(uint8_t *frm, struct ieee80211com *ic)
   {
           *frm++ = IEEE80211_ELEMID_VENDOR;
           *frm++ = 7;
           memcpy(frm, MICROSOFT_OUI, 3); frm += 3;
           *frm++ = 2; /* OUI type */
           *frm++ = 0; /* OUI subtype */
           *frm++ = 1; /* version */
           *frm++ = 0; /* info */
   
           return frm;
   }
   
   #ifndef IEEE80211_STA_ONLY
   /*
    * Add a Wifi-Alliance WMM (aka WME) parameter element to a frame.
    */
   uint8_t *
   ieee80211_add_wme_param(uint8_t *frm, struct ieee80211com *ic)
   {
           const struct ieee80211_edca_ac_params *edca;
           int aci;
   
           *frm++ = IEEE80211_ELEMID_VENDOR;
           *frm++ = 24;
           memcpy(frm, MICROSOFT_OUI, 3); frm += 3;
           *frm++ = 2; /* OUI type */
           *frm++ = 1; /* OUI subtype */
           *frm++ = 1; /* version */
           *frm++ = 0; /* info */
           *frm++ = 0; /* reserved */
   
           /* setup AC Parameter Records */
           edca = ieee80211_edca_table[ic->ic_curmode];
           for (aci = 0; aci < EDCA_NUM_AC; aci++) {
                   const struct ieee80211_edca_ac_params *ac = &edca[aci];
   
                   *frm++ = (aci << 5) | ((ac->ac_acm & 0x1) << 4) |
                            (ac->ac_aifsn & 0xf);
                   *frm++ = (ac->ac_ecwmax << 4) |
                            (ac->ac_ecwmin & 0xf);
                   LE_WRITE_2(frm, ac->ac_txoplimit); frm += 2;
           }
   
           return frm;
   }
   #endif
   
   /*
    * Add an RSN element to a frame (see 802.11-2012 8.4.2.27)
    */
   u_int8_t *
   ieee80211_add_rsn_body(u_int8_t *frm, struct ieee80211com *ic,
       const struct ieee80211_node *ni, int wpa)
   {
           const u_int8_t *oui = wpa ? MICROSOFT_OUI : IEEE80211_OUI;
           u_int8_t *pcount;
           u_int16_t count, rsncaps;
   
           /* write Version field */
           LE_WRITE_2(frm, 1); frm += 2;
   
           /* write Group Data Cipher Suite field (see 802.11-2012 Table 8-99) */
           memcpy(frm, oui, 3); frm += 3;
           switch (ni->ni_rsngroupcipher) {
           case IEEE80211_CIPHER_WEP40:
                   *frm++ = 1;
                   break;
           case IEEE80211_CIPHER_TKIP:
                   *frm++ = 2;
                   break;
           case IEEE80211_CIPHER_CCMP:
                   *frm++ = 4;
                   break;
           case IEEE80211_CIPHER_WEP104:
                  *frm++ = 5;
                  break;
          default:
                  /* can't get there */
                  panic("invalid group data cipher!");
          }
  
          pcount = frm; frm += 2;
          count = 0;
          /* write Pairwise Cipher Suite List */
          if (ni->ni_rsnciphers & IEEE80211_CIPHER_USEGROUP) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 0;
                  count++;
          }
          if (ni->ni_rsnciphers & IEEE80211_CIPHER_TKIP) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 2;
                  count++;
          }
          if (ni->ni_rsnciphers & IEEE80211_CIPHER_CCMP) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 4;
                  count++;
          }
          /* write Pairwise Cipher Suite Count field */
          LE_WRITE_2(pcount, count);
  
          pcount = frm; frm += 2;
          count = 0;
          /* write AKM Suite List (see Table 20dc) */
          if (ni->ni_rsnakms & IEEE80211_AKM_8021X) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 1;
                  count++;
          }
          if (ni->ni_rsnakms & IEEE80211_AKM_PSK) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 2;
                  count++;
          }
          if (!wpa && (ni->ni_rsnakms & IEEE80211_AKM_SHA256_8021X)) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 5;
                  count++;
          }
          if (!wpa && (ni->ni_rsnakms & IEEE80211_AKM_SHA256_PSK)) {
                  memcpy(frm, oui, 3); frm += 3;
                  *frm++ = 6;
                  count++;
          }
          /* write AKM Suite List Count field */
          LE_WRITE_2(pcount, count);
  
          if (wpa)
                  return frm;
  
          /* write RSN Capabilities field */
          rsncaps = (ni->ni_rsncaps & (IEEE80211_RSNCAP_PTKSA_RCNT_MASK |
              IEEE80211_RSNCAP_GTKSA_RCNT_MASK));
          if (ic->ic_caps & IEEE80211_C_MFP) {
                  rsncaps |= IEEE80211_RSNCAP_MFPC;
                  if (ic->ic_flags & IEEE80211_F_MFPR)
                          rsncaps |= IEEE80211_RSNCAP_MFPR;
          }
          if (ic->ic_flags & IEEE80211_F_PBAR)
                  rsncaps |= IEEE80211_RSNCAP_PBAC;
          LE_WRITE_2(frm, rsncaps); frm += 2;
  
          if (ni->ni_flags & IEEE80211_NODE_PMKID) {
                  /* write PMKID Count field */
                  LE_WRITE_2(frm, 1); frm += 2;
                  /* write PMKID List (only 1) */
                  memcpy(frm, ni->ni_pmkid, IEEE80211_PMKID_LEN);
                  frm += IEEE80211_PMKID_LEN;
          }
  
          if (!(ic->ic_caps & IEEE80211_C_MFP))
                  return frm;
  
          if ((ni->ni_flags & IEEE80211_NODE_PMKID) == 0) {
                  /* no PMKID (PMKID Count=0) */
                  LE_WRITE_2(frm, 0); frm += 2;
          }
  
          /* write Group Integrity Cipher Suite field */
          memcpy(frm, oui, 3); frm += 3;
          switch (ic->ic_rsngroupmgmtcipher) {
          case IEEE80211_CIPHER_BIP:
                  *frm++ = 6;
                  break;
          default:
                  /* can't get there */
                  panic("invalid integrity group cipher!");
          }
          return frm;
  }
  
  u_int8_t *
  ieee80211_add_rsn(u_int8_t *frm, struct ieee80211com *ic,
      const struct ieee80211_node *ni)
  {
          u_int8_t *plen;
  
          *frm++ = IEEE80211_ELEMID_RSN;
          plen = frm++;   /* length filled in later */
          frm = ieee80211_add_rsn_body(frm, ic, ni, 0);
  
          /* write length field */
          *plen = frm - plen - 1;
          return frm;
  }
  
  /*
   * Add a vendor-specific WPA element to a frame.
   * This is required for compatibility with Wi-Fi Alliance WPA.
   */
  u_int8_t *
  ieee80211_add_wpa(u_int8_t *frm, struct ieee80211com *ic,
      const struct ieee80211_node *ni)
  {
          u_int8_t *plen;
  
          *frm++ = IEEE80211_ELEMID_VENDOR;
          plen = frm++;   /* length filled in later */
          memcpy(frm, MICROSOFT_OUI, 3); frm += 3;
          *frm++ = 1;     /* WPA */
          frm = ieee80211_add_rsn_body(frm, ic, ni, 1);
  
          /* write length field */
          *plen = frm - plen - 1;
          return frm;
  }
  
  /*
   * Add an extended supported rates element to a frame (see 7.3.2.14).
   */
  u_int8_t *
  ieee80211_add_xrates(u_int8_t *frm, const struct ieee80211_rateset *rs)
  {
          int nrates;
  
          KASSERT(rs->rs_nrates > IEEE80211_RATE_SIZE);
  
          *frm++ = IEEE80211_ELEMID_XRATES;
          nrates = rs->rs_nrates - IEEE80211_RATE_SIZE;
          *frm++ = nrates;
          memcpy(frm, rs->rs_rates + IEEE80211_RATE_SIZE, nrates);
          return frm + nrates;
  }
  
  /*
   * Add an HT Capabilities element to a frame (see 7.3.2.57).
   */
  u_int8_t *
  ieee80211_add_htcaps(u_int8_t *frm, struct ieee80211com *ic)
  {
          *frm++ = IEEE80211_ELEMID_HTCAPS;
          *frm++ = 26;
          LE_WRITE_2(frm, ic->ic_htcaps); frm += 2;
          *frm++ = ic->ic_ampdu_params;
          memcpy(frm, ic->ic_sup_mcs, 10); frm += 10;
          LE_WRITE_2(frm, (ic->ic_max_rxrate & IEEE80211_MCS_RX_RATE_HIGH));
          frm += 2;
          *frm++ = ic->ic_tx_mcs_set;
          *frm++ = 0; /* reserved */
          *frm++ = 0; /* reserved */
          *frm++ = 0; /* reserved */
          LE_WRITE_2(frm, ic->ic_htxcaps); frm += 2;
          LE_WRITE_4(frm, ic->ic_txbfcaps); frm += 4;
          *frm++ = ic->ic_aselcaps;
          return frm;
  }
  
  #ifndef IEEE80211_STA_ONLY
  /*
   * Add an HT Operation element to a frame (see 7.3.2.58).
   */
  u_int8_t *
  ieee80211_add_htop(u_int8_t *frm, struct ieee80211com *ic)
  {
          *frm++ = IEEE80211_ELEMID_HTOP;
          *frm++ = 22;
          *frm++ = ieee80211_chan2ieee(ic, ic->ic_bss->ni_chan);
          *frm++ = ic->ic_bss->ni_htop0;
          LE_WRITE_2(frm, ic->ic_bss->ni_htop1); frm += 2;
          LE_WRITE_2(frm, ic->ic_bss->ni_htop2); frm += 2;
          memset(frm, 0, 16); frm += 16;
          return frm;
  }
  #endif  /* !IEEE80211_STA_ONLY */
  
  /*
   * Add a VHT Capabilities element to a frame (see 802.11ac-2013 8.4.2.160.2).
   */
  u_int8_t *
  ieee80211_add_vhtcaps(u_int8_t *frm, struct ieee80211com *ic)
  {
          *frm++ = IEEE80211_ELEMID_VHTCAPS;
          *frm++ = 12;
          LE_WRITE_4(frm, ic->ic_vhtcaps); frm += 4;
          LE_WRITE_2(frm, ic->ic_vht_rxmcs); frm += 2;
          LE_WRITE_2(frm, ic->ic_vht_rx_max_lgi_mbit_s); frm += 2;
          LE_WRITE_2(frm, ic->ic_vht_txmcs); frm += 2;
          LE_WRITE_2(frm, ic->ic_vht_tx_max_lgi_mbit_s); frm += 2;
          return frm;
  }
  
  #ifndef IEEE80211_STA_ONLY
  /*
   * Add a Timeout Interval element to a frame (see 7.3.2.49).
   */
  u_int8_t *
  ieee80211_add_tie(u_int8_t *frm, u_int8_t type, u_int32_t value)
  {
          *frm++ = IEEE80211_ELEMID_TIE;
          *frm++ = 5;     /* length */
          *frm++ = type;  /* Timeout Interval type */
          LE_WRITE_4(frm, value);
          return frm + 4;
  }
  #endif
  
  struct mbuf *
  ieee80211_getmgmt(int flags, int type, u_int pktlen)
  {
          struct mbuf *m;
  
          /* reserve space for 802.11 header */
          pktlen += sizeof(struct ieee80211_frame);
  
          if (pktlen > MCLBYTES)
                  panic("management frame too large: %u", pktlen);
          MGETHDR(m, flags, type);
          if (m == NULL)
                  return NULL;
          if (pktlen > MHLEN) {
                  MCLGET(m, flags);
                  if (!(m->m_flags & M_EXT))
                          return m_free(m);
          }
          m->m_data += sizeof(struct ieee80211_frame);
          return m;
  }
  
  /*-
   * Probe request frame format:
   * [tlv] SSID
   * [tlv] Supported rates
   * [tlv] Extended Supported Rates (802.11g)
   * [tlv] HT Capabilities (802.11n)
   */
  struct mbuf *
  ieee80211_get_probe_req(struct ieee80211com *ic, struct ieee80211_node *ni)
  {
          const struct ieee80211_rateset *rs =
              &ic->ic_sup_rates[ieee80211_chan2mode(ic, ni->ni_chan)];
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA,
              2 + ic->ic_des_esslen +
              2 + min(rs->rs_nrates, IEEE80211_RATE_SIZE) +
              ((rs->rs_nrates > IEEE80211_RATE_SIZE) ?
                  2 + rs->rs_nrates - IEEE80211_RATE_SIZE : 0) +
              ((ic->ic_flags & IEEE80211_F_HTON) ? 28 + 9 : 0) +
              ((ic->ic_flags & IEEE80211_F_VHTON) ? 14 : 0));
          if (m == NULL)
                  return NULL;
  
          frm = mtod(m, u_int8_t *);
          frm = ieee80211_add_ssid(frm, ic->ic_des_essid, ic->ic_des_esslen);
          frm = ieee80211_add_rates(frm, rs);
          if (rs->rs_nrates > IEEE80211_RATE_SIZE)
                  frm = ieee80211_add_xrates(frm, rs);
          if (ic->ic_flags & IEEE80211_F_HTON) {
                  frm = ieee80211_add_htcaps(frm, ic);
                  frm = ieee80211_add_wme_info(frm, ic);
          }
          if (ic->ic_flags & IEEE80211_F_VHTON)
                  frm = ieee80211_add_htcaps(frm, ic);
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  #ifndef IEEE80211_STA_ONLY
  /*-
   * Probe response frame format:
   * [8]   Timestamp
   * [2]   Beacon interval
   * [2]   Capability
   * [tlv] Service Set Identifier (SSID)
   * [tlv] Supported rates
   * [tlv] DS Parameter Set (802.11g)
   * [tlv] ERP Information (802.11g)
   * [tlv] Extended Supported Rates (802.11g)
   * [tlv] RSN (802.11i)
   * [tlv] EDCA Parameter Set (802.11e)
   * [tlv] HT Capabilities (802.11n)
   * [tlv] HT Operation (802.11n)
   */
  struct mbuf *
  ieee80211_get_probe_resp(struct ieee80211com *ic)
  {
          const struct ieee80211_rateset *rs = &ic->ic_bss->ni_rates;
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA,
              8 + 2 + 2 +
              2 + ic->ic_bss->ni_esslen +
              2 + min(rs->rs_nrates, IEEE80211_RATE_SIZE) +
              2 + 1 +
              ((ic->ic_opmode == IEEE80211_M_IBSS) ? 2 + 2 : 0) +
              ((ic->ic_curmode == IEEE80211_MODE_11G) ? 2 + 1 : 0) +
              ((rs->rs_nrates > IEEE80211_RATE_SIZE) ?
                  2 + rs->rs_nrates - IEEE80211_RATE_SIZE : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ic->ic_bss->ni_rsnprotos & IEEE80211_PROTO_RSN)) ?
                  2 + IEEE80211_RSNIE_MAXLEN : 0) +
              ((ic->ic_flags & IEEE80211_F_QOS) ? 2 + 18 : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ic->ic_bss->ni_rsnprotos & IEEE80211_PROTO_WPA)) ?
                  2 + IEEE80211_WPAIE_MAXLEN : 0) +
              ((ic->ic_flags & IEEE80211_F_HTON) ? 28 + 24 + 26 : 0));
          if (m == NULL)
                  return NULL;
  
          frm = mtod(m, u_int8_t *);
          memset(frm, 0, 8); frm += 8;    /* timestamp is set by hardware */
          LE_WRITE_2(frm, ic->ic_bss->ni_intval); frm += 2;
          frm = ieee80211_add_capinfo(frm, ic, ic->ic_bss);
          frm = ieee80211_add_ssid(frm, ic->ic_bss->ni_essid,
              ic->ic_bss->ni_esslen);
          frm = ieee80211_add_rates(frm, rs);
          frm = ieee80211_add_ds_params(frm, ic, ic->ic_bss);
          if (ic->ic_opmode == IEEE80211_M_IBSS)
                  frm = ieee80211_add_ibss_params(frm, ic->ic_bss);
          if (ic->ic_curmode == IEEE80211_MODE_11G)
                  frm = ieee80211_add_erp(frm, ic);
          if (rs->rs_nrates > IEEE80211_RATE_SIZE)
                  frm = ieee80211_add_xrates(frm, rs);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ic->ic_bss->ni_rsnprotos & IEEE80211_PROTO_RSN))
                  frm = ieee80211_add_rsn(frm, ic, ic->ic_bss);
          if (ic->ic_flags & IEEE80211_F_QOS)
                  frm = ieee80211_add_edca_params(frm, ic);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ic->ic_bss->ni_rsnprotos & IEEE80211_PROTO_WPA))
                  frm = ieee80211_add_wpa(frm, ic, ic->ic_bss);
          if (ic->ic_flags & IEEE80211_F_HTON) {
                  frm = ieee80211_add_htcaps(frm, ic);
                  frm = ieee80211_add_htop(frm, ic);
                  frm = ieee80211_add_wme_param(frm, ic);
          }
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  #endif  /* IEEE80211_STA_ONLY */
  
  /*-
   * Authentication frame format:
   * [2] Authentication algorithm number
   * [2] Authentication transaction sequence number
   * [2] Status code
   */
  struct mbuf *
  ieee80211_get_auth(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int16_t status, u_int16_t seq)
  {
          struct mbuf *m;
          u_int8_t *frm;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
          m_align(m, 2 * 3);
          m->m_pkthdr.len = m->m_len = 2 * 3;
  
          frm = mtod(m, u_int8_t *);
          LE_WRITE_2(frm, IEEE80211_AUTH_ALG_OPEN); frm += 2;
          LE_WRITE_2(frm, seq); frm += 2;
          LE_WRITE_2(frm, status);
  
          return m;
  }
  
  /*-
   * Deauthentication frame format:
   * [2] Reason code
   */
  struct mbuf *
  ieee80211_get_deauth(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int16_t reason)
  {
          struct mbuf *m;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
          m_align(m, 2);
          m->m_pkthdr.len = m->m_len = 2;
  
          *mtod(m, u_int16_t *) = htole16(reason);
  
          return m;
  }
  
  /*-
   * (Re)Association request frame format:
   * [2]   Capability information
   * [2]   Listen interval
   * [6*]  Current AP address (Reassociation only)
   * [tlv] SSID
   * [tlv] Supported rates
   * [tlv] Extended Supported Rates (802.11g)
   * [tlv] RSN (802.11i)
   * [tlv] QoS Capability (802.11e)
   * [tlv] HT Capabilities (802.11n)
   */
  struct mbuf *
  ieee80211_get_assoc_req(struct ieee80211com *ic, struct ieee80211_node *ni,
      int type)
  {
          const struct ieee80211_rateset *rs = &ni->ni_rates;
          struct mbuf *m;
          u_int8_t *frm;
          u_int16_t capinfo;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA,
              2 + 2 +
              ((type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) ?
                  IEEE80211_ADDR_LEN : 0) +
              2 + ni->ni_esslen +
              2 + min(rs->rs_nrates, IEEE80211_RATE_SIZE) +
              ((rs->rs_nrates > IEEE80211_RATE_SIZE) ?
                  2 + rs->rs_nrates - IEEE80211_RATE_SIZE : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ni->ni_rsnprotos & IEEE80211_PROTO_RSN)) ?
                  2 + IEEE80211_RSNIE_MAXLEN : 0) +
              ((ni->ni_flags & IEEE80211_NODE_QOS) ? 2 + 1 : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ni->ni_rsnprotos & IEEE80211_PROTO_WPA)) ?
                  2 + IEEE80211_WPAIE_MAXLEN : 0) +
              ((ic->ic_flags & IEEE80211_F_HTON) ? 28 + 9 : 0) +
              ((ic->ic_flags & IEEE80211_F_VHTON) ? 14 : 0));
          if (m == NULL)
                  return NULL;
  
          frm = mtod(m, u_int8_t *);
          capinfo = IEEE80211_CAPINFO_ESS;
          if (ic->ic_flags & IEEE80211_F_WEPON)
                  capinfo |= IEEE80211_CAPINFO_PRIVACY;
          if ((ic->ic_flags & IEEE80211_F_SHPREAMBLE) &&
              IEEE80211_IS_CHAN_2GHZ(ni->ni_chan))
                  capinfo |= IEEE80211_CAPINFO_SHORT_PREAMBLE;
          if (ic->ic_caps & IEEE80211_C_SHSLOT)
                  capinfo |= IEEE80211_CAPINFO_SHORT_SLOTTIME;
          LE_WRITE_2(frm, capinfo); frm += 2;
          LE_WRITE_2(frm, ic->ic_lintval); frm += 2;
          if (type == IEEE80211_FC0_SUBTYPE_REASSOC_REQ) {
                  IEEE80211_ADDR_COPY(frm, ic->ic_bss->ni_bssid);
                  frm += IEEE80211_ADDR_LEN;
          }
          frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
          frm = ieee80211_add_rates(frm, rs);
          if (rs->rs_nrates > IEEE80211_RATE_SIZE)
                  frm = ieee80211_add_xrates(frm, rs);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ni->ni_rsnprotos & IEEE80211_PROTO_RSN))
                  frm = ieee80211_add_rsn(frm, ic, ni);
          if (ni->ni_flags & IEEE80211_NODE_QOS)
                  frm = ieee80211_add_qos_capability(frm, ic);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ni->ni_rsnprotos & IEEE80211_PROTO_WPA))
                  frm = ieee80211_add_wpa(frm, ic, ni);
          if (ic->ic_flags & IEEE80211_F_HTON) {
                  frm = ieee80211_add_htcaps(frm, ic);
                  frm = ieee80211_add_wme_info(frm, ic);
          }
          if (ic->ic_flags & IEEE80211_F_VHTON)
                  frm = ieee80211_add_vhtcaps(frm, ic);
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  #ifndef IEEE80211_STA_ONLY
  /*-
   * (Re)Association response frame format:
   * [2]   Capability information
   * [2]   Status code
   * [2]   Association ID (AID)
   * [tlv] Supported rates
   * [tlv] Extended Supported Rates (802.11g)
   * [tlv] EDCA Parameter Set (802.11e)
   * [tlv] Timeout Interval (802.11w)
   * [tlv] HT Capabilities (802.11n)
   * [tlv] HT Operation (802.11n)
   */
  struct mbuf *
  ieee80211_get_assoc_resp(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int16_t status)
  {
          const struct ieee80211_rateset *rs = &ni->ni_rates;
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA,
              2 + 2 + 2 +
              2 + min(rs->rs_nrates, IEEE80211_RATE_SIZE) +
              ((rs->rs_nrates > IEEE80211_RATE_SIZE) ?
                  2 + rs->rs_nrates - IEEE80211_RATE_SIZE : 0) +
              ((ni->ni_flags & IEEE80211_NODE_QOS) ? 2 + 18 : 0) +
              ((status == IEEE80211_STATUS_TRY_AGAIN_LATER) ? 2 + 7 : 0) +
              ((ic->ic_flags & IEEE80211_F_HTON) ? 28 + 24 + 26 : 0));
          if (m == NULL)
                  return NULL;
  
          frm = mtod(m, u_int8_t *);
          frm = ieee80211_add_capinfo(frm, ic, ni);
          LE_WRITE_2(frm, status); frm += 2;
          if (status == IEEE80211_STATUS_SUCCESS)
                  LE_WRITE_2(frm, ni->ni_associd);
          else
                  LE_WRITE_2(frm, 0);
          frm += 2;
          frm = ieee80211_add_rates(frm, rs);
          if (rs->rs_nrates > IEEE80211_RATE_SIZE)
                  frm = ieee80211_add_xrates(frm, rs);
          if (ni->ni_flags & IEEE80211_NODE_QOS)
                  frm = ieee80211_add_edca_params(frm, ic);
          if ((ni->ni_flags & IEEE80211_NODE_MFP) &&
              status == IEEE80211_STATUS_TRY_AGAIN_LATER) {
                  /* Association Comeback Time */
                  frm = ieee80211_add_tie(frm, 3, 1000 /* XXX */);
          }
          if (ic->ic_flags & IEEE80211_F_HTON) {
                  frm = ieee80211_add_htcaps(frm, ic);
                  frm = ieee80211_add_htop(frm, ic);
                  frm = ieee80211_add_wme_param(frm, ic);
          }
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  #endif  /* IEEE80211_STA_ONLY */
  
  /*-
   * Disassociation frame format:
   * [2] Reason code
   */
  struct mbuf *
  ieee80211_get_disassoc(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int16_t reason)
  {
          struct mbuf *m;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
          m_align(m, 2);
          m->m_pkthdr.len = m->m_len = 2;
  
          *mtod(m, u_int16_t *) = htole16(reason);
  
          return m;
  }
  
  /*-
   * ADDBA Request frame format:
   * [1] Category
   * [1] Action
   * [1] Dialog Token
   * [2] Block Ack Parameter Set
   * [2] Block Ack Timeout Value
   * [2] Block Ack Starting Sequence Control
   */
  struct mbuf *
  ieee80211_get_addba_req(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int8_t tid)
  {
          struct ieee80211_tx_ba *ba = &ni->ni_tx_ba[tid];
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA, 9);
          if (m == NULL)
                  return m;
  
          frm = mtod(m, u_int8_t *);
          *frm++ = IEEE80211_CATEG_BA;
          *frm++ = IEEE80211_ACTION_ADDBA_REQ;
          *frm++ = ba->ba_token;
          LE_WRITE_2(frm, ba->ba_params); frm += 2;
          LE_WRITE_2(frm, ba->ba_timeout_val / IEEE80211_DUR_TU); frm += 2;
          LE_WRITE_2(frm, ba->ba_winstart << IEEE80211_SEQ_SEQ_SHIFT); frm += 2;
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  /* Move Tx BA window forward to the specified SSN. */
  void
  ieee80211_output_ba_move_window(struct ieee80211com *ic,
      struct ieee80211_node *ni, uint8_t tid, uint16_t ssn)
  {
          struct ieee80211_tx_ba *ba = &ni->ni_tx_ba[tid];
          uint16_t s = ba->ba_winstart;
  
          while (SEQ_LT(s, ssn) && ba->ba_bitmap) {
                  s = (s + 1) % 0xfff;
                  ba->ba_bitmap >>= 1;
          }
  
          ba->ba_winstart = (ssn & 0xfff);
          ba->ba_winend = (ba->ba_winstart + ba->ba_winsize - 1) & 0xfff;
  }
  
  /*
   * Move Tx BA window forward up to the first hole in the bitmap
   * or up to the specified SSN, whichever comes first.
   * After calling this function, frames before the start of the
   * potentially changed BA window should be discarded.
   */
  void
  ieee80211_output_ba_move_window_to_first_unacked(struct ieee80211com *ic,
      struct ieee80211_node *ni, uint8_t tid, uint16_t ssn)
  {
          struct ieee80211_tx_ba *ba = &ni->ni_tx_ba[tid];
          uint16_t s = ba->ba_winstart;
          uint64_t bitmap = ba->ba_bitmap;
          int can_move_window = 0;
  
          while (bitmap && SEQ_LT(s, ssn)) {
                  if ((bitmap & 1) == 0)
                          break;
                  s = (s + 1) % 0xfff;
                  bitmap >>= 1;
                  can_move_window = 1;
          }
  
          if (can_move_window)
                  ieee80211_output_ba_move_window(ic, ni, tid, s);
  }
  
  /* Record an ACK for a frame with a given SSN within the Tx BA window. */
  void
  ieee80211_output_ba_record_ack(struct ieee80211com *ic,
      struct ieee80211_node *ni, uint8_t tid, uint16_t ssn)
  {
          struct ieee80211_tx_ba *ba = &ni->ni_tx_ba[tid];
          int i = 0;
          uint16_t s = ba->ba_winstart;
  
          KASSERT(!SEQ_LT(ssn, ba->ba_winstart));
          KASSERT(!SEQ_LT(ba->ba_winend, ssn));
  
          while (SEQ_LT(s, ssn)) {
                  s = (s + 1) % 0xfff;
                  i++;
          }
          if (i < ba->ba_winsize)
                  ba->ba_bitmap |= (1 << i);
  }
  
  /*-
   * ADDBA Response frame format:
   * [1] Category
   * [1] Action
   * [1] Dialog Token
   * [2] Status Code
   * [2] Block Ack Parameter Set
   * [2] Block Ack Timeout Value
   */
  struct mbuf *
  ieee80211_get_addba_resp(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int8_t tid, u_int8_t token, u_int16_t status)
  {
          struct ieee80211_rx_ba *ba = &ni->ni_rx_ba[tid];
          struct mbuf *m;
          u_int8_t *frm;
          u_int16_t params;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA, 9);
          if (m == NULL)
                  return m;
  
          frm = mtod(m, u_int8_t *);
          *frm++ = IEEE80211_CATEG_BA;
          *frm++ = IEEE80211_ACTION_ADDBA_RESP;
          *frm++ = token;
          LE_WRITE_2(frm, status); frm += 2;
          if (status == 0)
                  params = ba->ba_params;
          else
                  params = tid << IEEE80211_ADDBA_TID_SHIFT;
          LE_WRITE_2(frm, params); frm += 2;
          if (status == 0)
                  LE_WRITE_2(frm, ba->ba_timeout_val / IEEE80211_DUR_TU);
          else
                  LE_WRITE_2(frm, 0);
          frm += 2;
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  /*-
   * DELBA frame format:
   * [1] Category
   * [1] Action
   * [2] DELBA Parameter Set
   * [2] Reason Code
   */
  struct mbuf *
  ieee80211_get_delba(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int8_t tid, u_int8_t dir, u_int16_t reason)
  {
          struct mbuf *m;
          u_int8_t *frm;
          u_int16_t params;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA, 6);
          if (m == NULL)
                  return m;
  
          frm = mtod(m, u_int8_t *);
          *frm++ = IEEE80211_CATEG_BA;
          *frm++ = IEEE80211_ACTION_DELBA;
          params = tid << 12;
          if (dir)
                  params |= IEEE80211_DELBA_INITIATOR;
          LE_WRITE_2(frm, params); frm += 2;
          LE_WRITE_2(frm, reason); frm += 2;
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  /*-
   * SA Query Request/Response frame format:
   * [1]  Category
   * [1]  Action
   * [16] Transaction Identifier
   */
  struct mbuf *
  ieee80211_get_sa_query(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int8_t action)
  {
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA, 4);
          if (m == NULL)
                  return NULL;
  
          frm = mtod(m, u_int8_t *);
          *frm++ = IEEE80211_CATEG_SA_QUERY;
          *frm++ = action;        /* ACTION_SA_QUERY_REQ/RESP */
          LE_WRITE_2(frm, ni->ni_sa_query_trid); frm += 2;
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
  
          return m;
  }
  
  struct mbuf *
  ieee80211_get_action(struct ieee80211com *ic, struct ieee80211_node *ni,
      u_int8_t categ, u_int8_t action, int arg)
  {
          struct mbuf *m = NULL;
  
          switch (categ) {
          case IEEE80211_CATEG_BA:
                  switch (action) {
                  case IEEE80211_ACTION_ADDBA_REQ:
                          m = ieee80211_get_addba_req(ic, ni, arg & 0xffff);
                          break;
                  case IEEE80211_ACTION_ADDBA_RESP:
                          m = ieee80211_get_addba_resp(ic, ni, arg & 0xff,
                              arg >> 8, arg >> 16);
                          break;
                  case IEEE80211_ACTION_DELBA:
                          m = ieee80211_get_delba(ic, ni, arg & 0xff, arg >> 8,
                              arg >> 16);
                          break;
                  }
                  break;
          case IEEE80211_CATEG_SA_QUERY:
                  switch (action) {
  #ifndef IEEE80211_STA_ONLY
                  case IEEE80211_ACTION_SA_QUERY_REQ:
  #endif
                  case IEEE80211_ACTION_SA_QUERY_RESP:
                          m = ieee80211_get_sa_query(ic, ni, action);
                          break;
                  }
                  break;
          }
          return m;
  }
  
  /*
   * Send a management frame.  The node is for the destination (or ic_bss
   * when in station mode).  Nodes other than ic_bss have their reference
   * count bumped to reflect our use for an indeterminant time.
   */
  int
  ieee80211_send_mgmt(struct ieee80211com *ic, struct ieee80211_node *ni,
      int type, int arg1, int arg2)
  {
  #define senderr(_x, _v) do { ic->ic_stats._v++; ret = _x; goto bad; } while (0)
          struct ifnet *ifp = &ic->ic_if;
          struct mbuf *m;
          int ret, timer;
  
          if (ni == NULL)
                  panic("null node");
  
          /*
           * Hold a reference on the node so it doesn't go away until after
           * the xmit is complete all the way in the driver.  On error we
           * will remove our reference.
           */
          ieee80211_ref_node(ni);
          timer = 0;
          switch (type) {
          case IEEE80211_FC0_SUBTYPE_PROBE_REQ:
                  if ((m = ieee80211_get_probe_req(ic, ni)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
  
                  timer = IEEE80211_TRANS_WAIT;
                  break;
  #ifndef IEEE80211_STA_ONLY
          case IEEE80211_FC0_SUBTYPE_PROBE_RESP:
                  if ((m = ieee80211_get_probe_resp(ic)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
                  break;
  #endif
          case IEEE80211_FC0_SUBTYPE_AUTH:
                  m = ieee80211_get_auth(ic, ni, arg1 >> 16, arg1 & 0xffff);
                  if (m == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
  
                  if (ic->ic_opmode == IEEE80211_M_STA)
                          timer = IEEE80211_TRANS_WAIT;
                  break;
  
          case IEEE80211_FC0_SUBTYPE_DEAUTH:
                  if ((m = ieee80211_get_deauth(ic, ni, arg1)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
  #ifndef IEEE80211_STA_ONLY
                  if ((ifp->if_flags & IFF_DEBUG) &&
                      (ic->ic_opmode == IEEE80211_M_HOSTAP ||
                      ic->ic_opmode == IEEE80211_M_IBSS))
                          printf("%s: station %s deauthenticate (reason %d)\n",
                              ifp->if_xname, ether_sprintf(ni->ni_macaddr),
                              arg1);
  #endif
                  break;
  
          case IEEE80211_FC0_SUBTYPE_ASSOC_REQ:
          case IEEE80211_FC0_SUBTYPE_REASSOC_REQ:
                  if ((m = ieee80211_get_assoc_req(ic, ni, type)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
  
                  timer = IEEE80211_TRANS_WAIT;
                  break;
  #ifndef IEEE80211_STA_ONLY
          case IEEE80211_FC0_SUBTYPE_ASSOC_RESP:
          case IEEE80211_FC0_SUBTYPE_REASSOC_RESP:
                  if ((m = ieee80211_get_assoc_resp(ic, ni, arg1)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
                  break;
  #endif
          case IEEE80211_FC0_SUBTYPE_DISASSOC:
                  if ((m = ieee80211_get_disassoc(ic, ni, arg1)) == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
  #ifndef IEEE80211_STA_ONLY
                  if ((ifp->if_flags & IFF_DEBUG) &&
                      (ic->ic_opmode == IEEE80211_M_HOSTAP ||
                      ic->ic_opmode == IEEE80211_M_IBSS))
                          printf("%s: station %s disassociate (reason %d)\n",
                              ifp->if_xname, ether_sprintf(ni->ni_macaddr),
                              arg1);
  #endif
                  break;
  
          case IEEE80211_FC0_SUBTYPE_ACTION:
                  m = ieee80211_get_action(ic, ni, arg1 >> 16, arg1 & 0xffff,
                      arg2);
                  if (m == NULL)
                          senderr(ENOMEM, is_tx_nombuf);
                  break;
  
          default:
                  DPRINTF(("invalid mgmt frame type %u\n", type));
                  senderr(EINVAL, is_tx_unknownmgt);
                  /* NOTREACHED */
          }
  
          ret = ieee80211_mgmt_output(ifp, ni, m, type);
          if (ret == 0) {
                  if (timer)
                          ic->ic_mgt_timer = timer;
          } else {
  bad:
                  ieee80211_release_node(ic, ni);
          }
          return ret;
  #undef senderr
  }
  
  /*
   * Build a RTS (Request To Send) control frame (see 7.2.1.1).
   */
  struct mbuf *
  ieee80211_get_rts(struct ieee80211com *ic, const struct ieee80211_frame *wh,
      u_int16_t dur)
  {
          struct ieee80211_frame_rts *rts;
          struct mbuf *m;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
  
          m->m_pkthdr.len = m->m_len = sizeof(struct ieee80211_frame_rts);
  
          rts = mtod(m, struct ieee80211_frame_rts *);
          rts->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_CTL |
              IEEE80211_FC0_SUBTYPE_RTS;
          rts->i_fc[1] = IEEE80211_FC1_DIR_NODS;
          *(u_int16_t *)rts->i_dur = htole16(dur);
          IEEE80211_ADDR_COPY(rts->i_ra, wh->i_addr1);
          IEEE80211_ADDR_COPY(rts->i_ta, wh->i_addr2);
  
          return m;
  }
  
  /*
   * Build a CTS-to-self (Clear To Send) control frame (see 7.2.1.2).
   */
  struct mbuf *
  ieee80211_get_cts_to_self(struct ieee80211com *ic, u_int16_t dur)
  {
          struct ieee80211_frame_cts *cts;
          struct mbuf *m;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
  
          m->m_pkthdr.len = m->m_len = sizeof(struct ieee80211_frame_cts);
  
          cts = mtod(m, struct ieee80211_frame_cts *);
          cts->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_CTL |
              IEEE80211_FC0_SUBTYPE_CTS;
          cts->i_fc[1] = IEEE80211_FC1_DIR_NODS;
          *(u_int16_t *)cts->i_dur = htole16(dur);
          IEEE80211_ADDR_COPY(cts->i_ra, ic->ic_myaddr);
  
          return m;
  }
  
  /*
   * Build a compressed Block Ack Request control frame.
   */
  struct mbuf *
  ieee80211_get_compressed_bar(struct ieee80211com *ic,
      struct ieee80211_node *ni, int tid, uint16_t ssn)
  {
          struct ieee80211_frame_min *wh;
          uint8_t *frm;
          uint16_t ctl;
          struct mbuf *m;
  
          MGETHDR(m, M_DONTWAIT, MT_DATA);
          if (m == NULL)
                  return NULL;
  
          m->m_pkthdr.len = m->m_len = sizeof(struct ieee80211_frame_min) +
              sizeof(ctl) + sizeof(ssn);
  
          wh = mtod(m, struct ieee80211_frame_min *);
          wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_CTL |
              IEEE80211_FC0_SUBTYPE_BAR;
          wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
          *(u_int16_t *)wh->i_dur = 0;
          IEEE80211_ADDR_COPY(wh->i_addr1, ni->ni_macaddr);
          IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
          frm = (uint8_t *)&wh[1];
  
          ctl = IEEE80211_BA_COMPRESSED | (tid << IEEE80211_BA_TID_INFO_SHIFT);
          LE_WRITE_2(frm, ctl);
          frm += 2;
  
          LE_WRITE_2(frm, ssn << IEEE80211_SEQ_SEQ_SHIFT);
          frm += 2;
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
          m->m_pkthdr.ph_cookie = ni;
  
          return m;
  }
  
  #ifndef IEEE80211_STA_ONLY
  /*-
   * Beacon frame format:
   * [8]   Timestamp
   * [2]   Beacon interval
   * [2]   Capability
   * [tlv] Service Set Identifier (SSID)
   * [tlv] Supported rates
   * [tlv] DS Parameter Set (802.11g)
   * [tlv] IBSS Parameter Set
   * [tlv] Traffic Indication Map (TIM)
   * [tlv] ERP Information (802.11g)
   * [tlv] Extended Supported Rates (802.11g)
   * [tlv] RSN (802.11i)
   * [tlv] EDCA Parameter Set (802.11e)
   * [tlv] HT Capabilities (802.11n)
   * [tlv] HT Operation (802.11n)
   */
  struct mbuf *
  ieee80211_beacon_alloc(struct ieee80211com *ic, struct ieee80211_node *ni)
  {
          const struct ieee80211_rateset *rs = &ni->ni_rates;
          struct ieee80211_frame *wh;
          struct mbuf *m;
          u_int8_t *frm;
  
          m = ieee80211_getmgmt(M_DONTWAIT, MT_DATA,
              8 + 2 + 2 +
              2 + ((ic->ic_userflags & IEEE80211_F_HIDENWID) ?
              0 : ni->ni_esslen) +
              2 + min(rs->rs_nrates, IEEE80211_RATE_SIZE) +
              2 + 1 +
              2 + ((ic->ic_opmode == IEEE80211_M_IBSS) ? 2 : 254) +
              ((ic->ic_curmode == IEEE80211_MODE_11G) ? 2 + 1 : 0) +
              ((rs->rs_nrates > IEEE80211_RATE_SIZE) ?
                  2 + rs->rs_nrates - IEEE80211_RATE_SIZE : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ni->ni_rsnprotos & IEEE80211_PROTO_RSN)) ?
                  2 + IEEE80211_RSNIE_MAXLEN : 0) +
              ((ic->ic_flags & IEEE80211_F_QOS) ? 2 + 18 : 0) +
              (((ic->ic_flags & IEEE80211_F_RSNON) &&
                (ni->ni_rsnprotos & IEEE80211_PROTO_WPA)) ?
                  2 + IEEE80211_WPAIE_MAXLEN : 0) +
              ((ic->ic_flags & IEEE80211_F_HTON) ? 28 + 24 + 26 : 0));
          if (m == NULL)
                  return NULL;
  
          M_PREPEND(m, sizeof(struct ieee80211_frame), M_DONTWAIT);
          if (m == NULL)
                  return NULL;
          wh = mtod(m, struct ieee80211_frame *);
          wh->i_fc[0] = IEEE80211_FC0_VERSION_0 | IEEE80211_FC0_TYPE_MGT |
              IEEE80211_FC0_SUBTYPE_BEACON;
          wh->i_fc[1] = IEEE80211_FC1_DIR_NODS;
          *(u_int16_t *)wh->i_dur = 0;
          IEEE80211_ADDR_COPY(wh->i_addr1, etherbroadcastaddr);
          IEEE80211_ADDR_COPY(wh->i_addr2, ic->ic_myaddr);
          IEEE80211_ADDR_COPY(wh->i_addr3, ni->ni_bssid);
          *(u_int16_t *)wh->i_seq = 0;
  
          frm = (u_int8_t *)&wh[1];
          memset(frm, 0, 8); frm += 8;    /* timestamp is set by hardware */
          LE_WRITE_2(frm, ni->ni_intval); frm += 2;
          frm = ieee80211_add_capinfo(frm, ic, ni);
          if (ic->ic_userflags & IEEE80211_F_HIDENWID)
                  frm = ieee80211_add_ssid(frm, NULL, 0);
          else
                  frm = ieee80211_add_ssid(frm, ni->ni_essid, ni->ni_esslen);
          frm = ieee80211_add_rates(frm, rs);
          frm = ieee80211_add_ds_params(frm, ic, ni);
          if (ic->ic_opmode == IEEE80211_M_IBSS)
                  frm = ieee80211_add_ibss_params(frm, ni);
          else
                  frm = ieee80211_add_tim(frm, ic);
          if (ic->ic_curmode == IEEE80211_MODE_11G)
                  frm = ieee80211_add_erp(frm, ic);
          if (rs->rs_nrates > IEEE80211_RATE_SIZE)
                  frm = ieee80211_add_xrates(frm, rs);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ni->ni_rsnprotos & IEEE80211_PROTO_RSN))
                  frm = ieee80211_add_rsn(frm, ic, ni);
          if (ic->ic_flags & IEEE80211_F_QOS)
                  frm = ieee80211_add_edca_params(frm, ic);
          if ((ic->ic_flags & IEEE80211_F_RSNON) &&
              (ni->ni_rsnprotos & IEEE80211_PROTO_WPA))
                  frm = ieee80211_add_wpa(frm, ic, ni);
          if (ic->ic_flags & IEEE80211_F_HTON) {
                  frm = ieee80211_add_htcaps(frm, ic);
                  frm = ieee80211_add_htop(frm, ic);
                  frm = ieee80211_add_wme_param(frm, ic);
          }
  
          m->m_pkthdr.len = m->m_len = frm - mtod(m, u_int8_t *);
          m->m_pkthdr.ph_cookie = ni;
  
          return m;
  }
  
  /*
   * Check if an outgoing MSDU or management frame should be buffered into
   * the AP for power management.  Return 1 if the frame was buffered into
   * the AP, or 0 if the frame shall be transmitted immediately.
   */
  int
  ieee80211_pwrsave(struct ieee80211com *ic, struct mbuf *m,
      struct ieee80211_node *ni)
  {
          const struct ieee80211_frame *wh;
          int pssta = 0;
  
          KASSERT(ic->ic_opmode == IEEE80211_M_HOSTAP);
          if (!(ic->ic_caps & IEEE80211_C_APPMGT))
                  return 0;
  
          wh = mtod(m, struct ieee80211_frame *);
          if (IEEE80211_IS_MULTICAST(wh->i_addr1)) {
                  /*
                   * Buffer group addressed MSDUs with the Order bit clear
                   * if any associated STAs are in PS mode.
                   */
                  ieee80211_iterate_nodes(ic, ieee80211_count_pssta, &pssta);
                  if ((wh->i_fc[1] & IEEE80211_FC1_ORDER) || pssta == 0)
                          return 0;
                  ic->ic_tim_mcast_pending = 1;
          } else {
                  /*
                   * Buffer MSDUs, A-MSDUs or management frames destined for
                   * PS STAs.
                   */
                  if (ni->ni_pwrsave == IEEE80211_PS_AWAKE ||
                      (wh->i_fc[0] & IEEE80211_FC0_TYPE_MASK) ==
                      IEEE80211_FC0_TYPE_CTL)
                          return 0;
                  if (mq_empty(&ni->ni_savedq))
                          (*ic->ic_set_tim)(ic, ni->ni_associd, 1);
          }
          /* NB: ni == ic->ic_bss for broadcast/multicast */
          /*
           * Similar to ieee80211_mgmt_output, store the node in a
           * special pkthdr field.
           */
          m->m_pkthdr.ph_cookie = ni;
          mq_enqueue(&ni->ni_savedq, m);
          return 1;
  }
  #endif  /* IEEE80211_STA_ONLY */

Cache object: 021101c9fd162793c781baed06dc36f7