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sys/net80211/ieee80211_ht.c

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  1 /*-
  2  * Copyright (c) 2007-2008 Sam Leffler, Errno Consulting
  3  * All rights reserved.
  4  *
  5  * Redistribution and use in source and binary forms, with or without
  6  * modification, are permitted provided that the following conditions
  7  * are met:
  8  * 1. Redistributions of source code must retain the above copyright
  9  *    notice, this list of conditions and the following disclaimer.
 10  * 2. Redistributions in binary form must reproduce the above copyright
 11  *    notice, this list of conditions and the following disclaimer in the
 12  *    documentation and/or other materials provided with the distribution.
 13  *
 14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 17  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 24  */
 25 
 26 #include <sys/cdefs.h>
 27 #ifdef __FreeBSD__
 28 __FBSDID("$FreeBSD: src/sys/net80211/ieee80211_ht.c,v 1.31 2008/10/26 00:43:11 sam Exp $");
 29 #endif
 30 
 31 /*
 32  * IEEE 802.11n protocol support.
 33  */
 34 
 35 #include "opt_inet.h"
 36 #include "opt_wlan.h"
 37 
 38 #include <sys/param.h>
 39 #include <sys/kernel.h>
 40 #include <sys/systm.h> 
 41 #include <sys/endian.h>
 42  
 43 #include <sys/socket.h>
 44 
 45 #include <net/if.h>
 46 #include <net/if_media.h>
 47 #include <net/ethernet.h>
 48 
 49 #include <net80211/ieee80211_var.h>
 50 #include <net80211/ieee80211_input.h>
 51 
 52 /* define here, used throughout file */
 53 #define MS(_v, _f)      (((_v) & _f) >> _f##_S)
 54 #define SM(_v, _f)      (((_v) << _f##_S) & _f)
 55 
 56 const struct ieee80211_mcs_rates ieee80211_htrates[16] = {
 57         {  13,  14,  27,  30 }, /* MCS 0 */
 58         {  26,  29,  54,  60 }, /* MCS 1 */
 59         {  39,  43,  81,  90 }, /* MCS 2 */
 60         {  52,  58, 108, 120 }, /* MCS 3 */
 61         {  78,  87, 162, 180 }, /* MCS 4 */
 62         { 104, 116, 216, 240 }, /* MCS 5 */
 63         { 117, 130, 243, 270 }, /* MCS 6 */
 64         { 130, 144, 270, 300 }, /* MCS 7 */
 65         {  26,  29,  54,  60 }, /* MCS 8 */
 66         {  52,  58, 108, 120 }, /* MCS 9 */
 67         {  78,  87, 162, 180 }, /* MCS 10 */
 68         { 104, 116, 216, 240 }, /* MCS 11 */
 69         { 156, 173, 324, 360 }, /* MCS 12 */
 70         { 208, 231, 432, 480 }, /* MCS 13 */
 71         { 234, 260, 486, 540 }, /* MCS 14 */
 72         { 260, 289, 540, 600 }  /* MCS 15 */
 73 };
 74 
 75 static const struct ieee80211_htrateset ieee80211_rateset_11n =
 76         { 16, {
 77                   0,   1,   2,   3,   4,  5,   6,  7,  8,  9,
 78                  10,  11,  12,  13,  14,  15 }
 79         };
 80 
 81 #ifdef IEEE80211_AMPDU_AGE
 82 /* XXX public for sysctl hookup */
 83 int     ieee80211_ampdu_age = -1;       /* threshold for ampdu reorder q (ms) */
 84 #endif
 85 int     ieee80211_recv_bar_ena = 1;
 86 int     ieee80211_addba_timeout = -1;   /* timeout waiting for ADDBA response */
 87 int     ieee80211_addba_backoff = -1;   /* backoff after max ADDBA requests */
 88 int     ieee80211_addba_maxtries = 3;   /* max ADDBA requests before backoff */
 89 int     ieee80211_bar_timeout = -1;     /* timeout waiting for BAR response */
 90 int     ieee80211_bar_maxtries = 50;    /* max BAR requests before DELBA */
 91 
 92 /*
 93  * Setup HT parameters that depends on the clock frequency.
 94  */
 95 static void
 96 ieee80211_ht_setup(void)
 97 {
 98 #ifdef IEEE80211_AMPDU_AGE
 99         ieee80211_ampdu_age = msecs_to_ticks(500);
100 #endif
101         ieee80211_addba_timeout = msecs_to_ticks(250);
102         ieee80211_addba_backoff = msecs_to_ticks(10*1000);
103         ieee80211_bar_timeout = msecs_to_ticks(250);
104 }
105 SYSINIT(wlan_ht, SI_SUB_DRIVERS, SI_ORDER_FIRST, ieee80211_ht_setup, NULL);
106 
107 static int ieee80211_ampdu_enable(struct ieee80211_node *ni,
108         struct ieee80211_tx_ampdu *tap);
109 static int ieee80211_addba_request(struct ieee80211_node *ni,
110         struct ieee80211_tx_ampdu *tap,
111         int dialogtoken, int baparamset, int batimeout);
112 static int ieee80211_addba_response(struct ieee80211_node *ni,
113         struct ieee80211_tx_ampdu *tap,
114         int code, int baparamset, int batimeout);
115 static void ieee80211_addba_stop(struct ieee80211_node *ni,
116         struct ieee80211_tx_ampdu *tap);
117 static void ieee80211_aggr_recv_action(struct ieee80211_node *ni,
118         const uint8_t *frm, const uint8_t *efrm);
119 static void ieee80211_bar_response(struct ieee80211_node *ni,
120         struct ieee80211_tx_ampdu *tap, int status);
121 static void ampdu_tx_stop(struct ieee80211_tx_ampdu *tap);
122 static void bar_stop_timer(struct ieee80211_tx_ampdu *tap);
123 
124 void
125 ieee80211_ht_attach(struct ieee80211com *ic)
126 {
127         /* setup default aggregation policy */
128         ic->ic_recv_action = ieee80211_aggr_recv_action;
129         ic->ic_send_action = ieee80211_send_action;
130         ic->ic_ampdu_enable = ieee80211_ampdu_enable;
131         ic->ic_addba_request = ieee80211_addba_request;
132         ic->ic_addba_response = ieee80211_addba_response;
133         ic->ic_addba_stop = ieee80211_addba_stop;
134         ic->ic_bar_response = ieee80211_bar_response;
135 
136         ic->ic_htprotmode = IEEE80211_PROT_RTSCTS;
137         ic->ic_curhtprotmode = IEEE80211_HTINFO_OPMODE_PURE;
138 }
139 
140 void
141 ieee80211_ht_detach(struct ieee80211com *ic)
142 {
143 }
144 
145 void
146 ieee80211_ht_vattach(struct ieee80211vap *vap)
147 {
148 
149         /* driver can override defaults */
150         vap->iv_ampdu_rxmax = IEEE80211_HTCAP_MAXRXAMPDU_8K;
151         vap->iv_ampdu_density = IEEE80211_HTCAP_MPDUDENSITY_NA;
152         vap->iv_ampdu_limit = vap->iv_ampdu_rxmax;
153         vap->iv_amsdu_limit = vap->iv_htcaps & IEEE80211_HTCAP_MAXAMSDU;
154         /* tx aggregation traffic thresholds */
155         vap->iv_ampdu_mintraffic[WME_AC_BK] = 128;
156         vap->iv_ampdu_mintraffic[WME_AC_BE] = 64;
157         vap->iv_ampdu_mintraffic[WME_AC_VO] = 32;
158         vap->iv_ampdu_mintraffic[WME_AC_VI] = 32;
159 
160         if (vap->iv_htcaps & IEEE80211_HTC_HT) {
161                 /*
162                  * Device is HT capable; enable all HT-related
163                  * facilities by default.
164                  * XXX these choices may be too aggressive.
165                  */
166                 vap->iv_flags_ext |= IEEE80211_FEXT_HT
167                                   |  IEEE80211_FEXT_HTCOMPAT
168                                   ;
169                 if (vap->iv_htcaps & IEEE80211_HTCAP_SHORTGI20)
170                         vap->iv_flags_ext |= IEEE80211_FEXT_SHORTGI20;
171                 /* XXX infer from channel list? */
172                 if (vap->iv_htcaps & IEEE80211_HTCAP_CHWIDTH40) {
173                         vap->iv_flags_ext |= IEEE80211_FEXT_USEHT40;
174                         if (vap->iv_htcaps & IEEE80211_HTCAP_SHORTGI40)
175                                 vap->iv_flags_ext |= IEEE80211_FEXT_SHORTGI40;
176                 }
177                 /* enable RIFS if capable */
178                 if (vap->iv_htcaps & IEEE80211_HTC_RIFS)
179                         vap->iv_flags_ext |= IEEE80211_FEXT_RIFS;
180 
181                 /* NB: A-MPDU and A-MSDU rx are mandated, these are tx only */
182                 vap->iv_flags_ext |= IEEE80211_FEXT_AMPDU_RX;
183                 if (vap->iv_htcaps & IEEE80211_HTC_AMPDU)
184                         vap->iv_flags_ext |= IEEE80211_FEXT_AMPDU_TX;
185                 vap->iv_flags_ext |= IEEE80211_FEXT_AMSDU_RX;
186                 if (vap->iv_htcaps & IEEE80211_HTC_AMSDU)
187                         vap->iv_flags_ext |= IEEE80211_FEXT_AMSDU_TX;
188         }
189         /* NB: disable default legacy WDS, too many issues right now */
190         if (vap->iv_flags_ext & IEEE80211_FEXT_WDSLEGACY)
191                 vap->iv_flags_ext &= ~IEEE80211_FEXT_HT;
192 }
193 
194 void
195 ieee80211_ht_vdetach(struct ieee80211vap *vap)
196 {
197 }
198 
199 static void
200 ht_announce(struct ieee80211com *ic, int mode,
201         const struct ieee80211_htrateset *rs)
202 {
203         struct ifnet *ifp = ic->ic_ifp;
204         int i, rate, mword;
205 
206         if_printf(ifp, "%s MCS: ", ieee80211_phymode_name[mode]);
207         for (i = 0; i < rs->rs_nrates; i++) {
208                 mword = ieee80211_rate2media(ic,
209                     rs->rs_rates[i] | IEEE80211_RATE_MCS, mode);
210                 if (IFM_SUBTYPE(mword) != IFM_IEEE80211_MCS)
211                         continue;
212                 rate = ieee80211_htrates[rs->rs_rates[i]].ht40_rate_400ns;
213                 printf("%s%d%sMbps", (i != 0 ? " " : ""),
214                     rate / 2, ((rate & 0x1) != 0 ? ".5" : ""));
215         }
216         printf("\n");
217 }
218 
219 void
220 ieee80211_ht_announce(struct ieee80211com *ic)
221 {
222         if (isset(ic->ic_modecaps, IEEE80211_MODE_11NA))
223                 ht_announce(ic, IEEE80211_MODE_11NA, &ieee80211_rateset_11n);
224         if (isset(ic->ic_modecaps, IEEE80211_MODE_11NG))
225                 ht_announce(ic, IEEE80211_MODE_11NG, &ieee80211_rateset_11n);
226 }
227 
228 const struct ieee80211_htrateset *
229 ieee80211_get_suphtrates(struct ieee80211com *ic,
230         const struct ieee80211_channel *c)
231 {
232         return &ieee80211_rateset_11n;
233 }
234 
235 /*
236  * Receive processing.
237  */
238 
239 /*
240  * Decap the encapsulated A-MSDU frames and dispatch all but
241  * the last for delivery.  The last frame is returned for 
242  * delivery via the normal path.
243  */
244 struct mbuf *
245 ieee80211_decap_amsdu(struct ieee80211_node *ni, struct mbuf *m)
246 {
247         struct ieee80211vap *vap = ni->ni_vap;
248         int framelen;
249         struct mbuf *n;
250 
251         /* discard 802.3 header inserted by ieee80211_decap */
252         m_adj(m, sizeof(struct ether_header));
253 
254         vap->iv_stats.is_amsdu_decap++;
255 
256         for (;;) {
257                 /*
258                  * Decap the first frame, bust it apart from the
259                  * remainder and deliver.  We leave the last frame
260                  * delivery to the caller (for consistency with other
261                  * code paths, could also do it here).
262                  */
263                 m = ieee80211_decap1(m, &framelen);
264                 if (m == NULL) {
265                         IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_ANY,
266                             ni->ni_macaddr, "a-msdu", "%s", "decap failed");
267                         vap->iv_stats.is_amsdu_tooshort++;
268                         return NULL;
269                 }
270                 if (m->m_pkthdr.len == framelen)
271                         break;
272                 n = m_split(m, framelen, M_NOWAIT);
273                 if (n == NULL) {
274                         IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_ANY,
275                             ni->ni_macaddr, "a-msdu",
276                             "%s", "unable to split encapsulated frames");
277                         vap->iv_stats.is_amsdu_split++;
278                         m_freem(m);                     /* NB: must reclaim */
279                         return NULL;
280                 }
281                 vap->iv_deliver_data(vap, ni, m);
282 
283                 /*
284                  * Remove frame contents; each intermediate frame
285                  * is required to be aligned to a 4-byte boundary.
286                  */
287                 m = n;
288                 m_adj(m, roundup2(framelen, 4) - framelen);     /* padding */
289         }
290         return m;                               /* last delivered by caller */
291 }
292 
293 /*
294  * Purge all frames in the A-MPDU re-order queue.
295  */
296 static void
297 ampdu_rx_purge(struct ieee80211_rx_ampdu *rap)
298 {
299         struct mbuf *m;
300         int i;
301 
302         for (i = 0; i < rap->rxa_wnd; i++) {
303                 m = rap->rxa_m[i];
304                 if (m != NULL) {
305                         rap->rxa_m[i] = NULL;
306                         rap->rxa_qbytes -= m->m_pkthdr.len;
307                         m_freem(m);
308                         if (--rap->rxa_qframes == 0)
309                                 break;
310                 }
311         }
312         KASSERT(rap->rxa_qbytes == 0 && rap->rxa_qframes == 0,
313             ("lost %u data, %u frames on ampdu rx q",
314             rap->rxa_qbytes, rap->rxa_qframes));
315 }
316 
317 /*
318  * Start A-MPDU rx/re-order processing for the specified TID.
319  */
320 static void
321 ampdu_rx_start(struct ieee80211_rx_ampdu *rap, int bufsiz, int start)
322 {
323         if (rap->rxa_flags & IEEE80211_AGGR_RUNNING) {
324                 /*
325                  * AMPDU previously setup and not terminated with a DELBA,
326                  * flush the reorder q's in case anything remains.
327                  */
328                 ampdu_rx_purge(rap);
329         }
330         memset(rap, 0, sizeof(*rap));
331         rap->rxa_wnd = (bufsiz == 0) ?
332             IEEE80211_AGGR_BAWMAX : min(bufsiz, IEEE80211_AGGR_BAWMAX);
333         rap->rxa_start = start;
334         rap->rxa_flags |=  IEEE80211_AGGR_RUNNING | IEEE80211_AGGR_XCHGPEND;
335 }
336 
337 /*
338  * Stop A-MPDU rx processing for the specified TID.
339  */
340 static void
341 ampdu_rx_stop(struct ieee80211_rx_ampdu *rap)
342 {
343         ampdu_rx_purge(rap);
344         rap->rxa_flags &= ~(IEEE80211_AGGR_RUNNING | IEEE80211_AGGR_XCHGPEND);
345 }
346 
347 /*
348  * Dispatch a frame from the A-MPDU reorder queue.  The
349  * frame is fed back into ieee80211_input marked with an
350  * M_AMPDU_MPDU flag so it doesn't come back to us (it also
351  * permits ieee80211_input to optimize re-processing).
352  */
353 static __inline void
354 ampdu_dispatch(struct ieee80211_node *ni, struct mbuf *m)
355 {
356         m->m_flags |= M_AMPDU_MPDU;     /* bypass normal processing */
357         /* NB: rssi, noise, and rstamp are ignored w/ M_AMPDU_MPDU set */
358         (void) ieee80211_input(ni, m, 0, 0, 0);
359 }
360 
361 /*
362  * Dispatch as many frames as possible from the re-order queue.
363  * Frames will always be "at the front"; we process all frames
364  * up to the first empty slot in the window.  On completion we
365  * cleanup state if there are still pending frames in the current
366  * BA window.  We assume the frame at slot 0 is already handled
367  * by the caller; we always start at slot 1.
368  */
369 static void
370 ampdu_rx_dispatch(struct ieee80211_rx_ampdu *rap, struct ieee80211_node *ni)
371 {
372         struct ieee80211vap *vap = ni->ni_vap;
373         struct mbuf *m;
374         int i;
375 
376         /* flush run of frames */
377         for (i = 1; i < rap->rxa_wnd; i++) {
378                 m = rap->rxa_m[i];
379                 if (m == NULL)
380                         break;
381                 rap->rxa_m[i] = NULL;
382                 rap->rxa_qbytes -= m->m_pkthdr.len;
383                 rap->rxa_qframes--;
384 
385                 ampdu_dispatch(ni, m);
386         }
387         /*
388          * If frames remain, copy the mbuf pointers down so
389          * they correspond to the offsets in the new window.
390          */
391         if (rap->rxa_qframes != 0) {
392                 int n = rap->rxa_qframes, j;
393                 for (j = i+1; j < rap->rxa_wnd; j++) {
394                         if (rap->rxa_m[j] != NULL) {
395                                 rap->rxa_m[j-i] = rap->rxa_m[j];
396                                 rap->rxa_m[j] = NULL;
397                                 if (--n == 0)
398                                         break;
399                         }
400                 }
401                 KASSERT(n == 0, ("lost %d frames", n));
402                 vap->iv_stats.is_ampdu_rx_copy += rap->rxa_qframes;
403         }
404         /*
405          * Adjust the start of the BA window to
406          * reflect the frames just dispatched.
407          */
408         rap->rxa_start = IEEE80211_SEQ_ADD(rap->rxa_start, i);
409         vap->iv_stats.is_ampdu_rx_oor += i;
410 }
411 
412 #ifdef IEEE80211_AMPDU_AGE
413 /*
414  * Dispatch all frames in the A-MPDU re-order queue.
415  */
416 static void
417 ampdu_rx_flush(struct ieee80211_node *ni, struct ieee80211_rx_ampdu *rap)
418 {
419         struct ieee80211vap *vap = ni->ni_vap;
420         struct mbuf *m;
421         int i;
422 
423         for (i = 0; i < rap->rxa_wnd; i++) {
424                 m = rap->rxa_m[i];
425                 if (m == NULL)
426                         continue;
427                 rap->rxa_m[i] = NULL;
428                 rap->rxa_qbytes -= m->m_pkthdr.len;
429                 rap->rxa_qframes--;
430                 vap->iv_stats.is_ampdu_rx_oor++;
431 
432                 ampdu_dispatch(ni, m);
433                 if (rap->rxa_qframes == 0)
434                         break;
435         }
436 }
437 #endif /* IEEE80211_AMPDU_AGE */
438 
439 /*
440  * Dispatch all frames in the A-MPDU re-order queue
441  * preceding the specified sequence number.  This logic
442  * handles window moves due to a received MSDU or BAR.
443  */
444 static void
445 ampdu_rx_flush_upto(struct ieee80211_node *ni,
446         struct ieee80211_rx_ampdu *rap, ieee80211_seq winstart)
447 {
448         struct ieee80211vap *vap = ni->ni_vap;
449         struct mbuf *m;
450         ieee80211_seq seqno;
451         int i;
452 
453         /*
454          * Flush any complete MSDU's with a sequence number lower
455          * than winstart.  Gaps may exist.  Note that we may actually
456          * dispatch frames past winstart if a run continues; this is
457          * an optimization that avoids having to do a separate pass
458          * to dispatch frames after moving the BA window start.
459          */
460         seqno = rap->rxa_start;
461         for (i = 0; i < rap->rxa_wnd; i++) {
462                 m = rap->rxa_m[i];
463                 if (m != NULL) {
464                         rap->rxa_m[i] = NULL;
465                         rap->rxa_qbytes -= m->m_pkthdr.len;
466                         rap->rxa_qframes--;
467                         vap->iv_stats.is_ampdu_rx_oor++;
468 
469                         ampdu_dispatch(ni, m);
470                 } else {
471                         if (!IEEE80211_SEQ_BA_BEFORE(seqno, winstart))
472                                 break;
473                 }
474                 seqno = IEEE80211_SEQ_INC(seqno);
475         }
476         /*
477          * If frames remain, copy the mbuf pointers down so
478          * they correspond to the offsets in the new window.
479          */
480         if (rap->rxa_qframes != 0) {
481                 int n = rap->rxa_qframes, j;
482 
483                 /* NB: this loop assumes i > 0 and/or rxa_m[0] is NULL */
484                 KASSERT(rap->rxa_m[0] == NULL,
485                     ("%s: BA window slot 0 occupied", __func__));
486                 for (j = i+1; j < rap->rxa_wnd; j++) {
487                         if (rap->rxa_m[j] != NULL) {
488                                 rap->rxa_m[j-i] = rap->rxa_m[j];
489                                 rap->rxa_m[j] = NULL;
490                                 if (--n == 0)
491                                         break;
492                         }
493                 }
494                 KASSERT(n == 0, ("%s: lost %d frames, qframes %d off %d "
495                     "BA win <%d:%d> winstart %d",
496                     __func__, n, rap->rxa_qframes, i, rap->rxa_start,
497                     IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1),
498                     winstart));
499                 vap->iv_stats.is_ampdu_rx_copy += rap->rxa_qframes;
500         }
501         /*
502          * Move the start of the BA window; we use the
503          * sequence number of the last MSDU that was
504          * passed up the stack+1 or winstart if stopped on
505          * a gap in the reorder buffer.
506          */
507         rap->rxa_start = seqno;
508 }
509 
510 /*
511  * Process a received QoS data frame for an HT station.  Handle
512  * A-MPDU reordering: if this frame is received out of order
513  * and falls within the BA window hold onto it.  Otherwise if
514  * this frame completes a run, flush any pending frames.  We
515  * return 1 if the frame is consumed.  A 0 is returned if
516  * the frame should be processed normally by the caller.
517  */
518 int
519 ieee80211_ampdu_reorder(struct ieee80211_node *ni, struct mbuf *m)
520 {
521 #define IEEE80211_FC0_QOSDATA \
522         (IEEE80211_FC0_TYPE_DATA|IEEE80211_FC0_SUBTYPE_QOS|IEEE80211_FC0_VERSION_0)
523 #define PROCESS         0       /* caller should process frame */
524 #define CONSUMED        1       /* frame consumed, caller does nothing */
525         struct ieee80211vap *vap = ni->ni_vap;
526         struct ieee80211_qosframe *wh;
527         struct ieee80211_rx_ampdu *rap;
528         ieee80211_seq rxseq;
529         uint8_t tid;
530         int off;
531 
532         KASSERT((m->m_flags & (M_AMPDU | M_AMPDU_MPDU)) == M_AMPDU,
533             ("!a-mpdu or already re-ordered, flags 0x%x", m->m_flags));
534         KASSERT(ni->ni_flags & IEEE80211_NODE_HT, ("not an HT sta"));
535 
536         /* NB: m_len known to be sufficient */
537         wh = mtod(m, struct ieee80211_qosframe *);
538         if (wh->i_fc[0] != IEEE80211_FC0_QOSDATA) {
539                 /*
540                  * Not QoS data, shouldn't get here but just
541                  * return it to the caller for processing.
542                  */
543                 return PROCESS;
544         }
545         if ((wh->i_fc[1] & IEEE80211_FC1_DIR_MASK) == IEEE80211_FC1_DIR_DSTODS)
546                 tid = ((struct ieee80211_qosframe_addr4 *)wh)->i_qos[0];
547         else
548                 tid = wh->i_qos[0];
549         tid &= IEEE80211_QOS_TID;
550         rap = &ni->ni_rx_ampdu[tid];
551         if ((rap->rxa_flags & IEEE80211_AGGR_XCHGPEND) == 0) {
552                 /*
553                  * No ADDBA request yet, don't touch.
554                  */
555                 return PROCESS;
556         }
557         rxseq = le16toh(*(uint16_t *)wh->i_seq);
558         if ((rxseq & IEEE80211_SEQ_FRAG_MASK) != 0) {
559                 /*
560                  * Fragments are not allowed; toss.
561                  */
562                 IEEE80211_DISCARD_MAC(vap,
563                     IEEE80211_MSG_INPUT | IEEE80211_MSG_11N, ni->ni_macaddr,
564                     "A-MPDU", "fragment, rxseq 0x%x tid %u%s", rxseq, tid,
565                     wh->i_fc[1] & IEEE80211_FC1_RETRY ? " (retransmit)" : "");
566                 vap->iv_stats.is_ampdu_rx_drop++;
567                 IEEE80211_NODE_STAT(ni, rx_drop);
568                 m_freem(m);
569                 return CONSUMED;
570         }
571         rxseq >>= IEEE80211_SEQ_SEQ_SHIFT;
572         rap->rxa_nframes++;
573 again:
574         if (rxseq == rap->rxa_start) {
575                 /*
576                  * First frame in window.
577                  */
578                 if (rap->rxa_qframes != 0) {
579                         /*
580                          * Dispatch as many packets as we can.
581                          */
582                         KASSERT(rap->rxa_m[0] == NULL, ("unexpected dup"));
583                         ampdu_dispatch(ni, m);
584                         ampdu_rx_dispatch(rap, ni);
585                         return CONSUMED;
586                 } else {
587                         /*
588                          * In order; advance window and notify
589                          * caller to dispatch directly.
590                          */
591                         rap->rxa_start = IEEE80211_SEQ_INC(rxseq);
592                         return PROCESS;
593                 }
594         }
595         /*
596          * Frame is out of order; store if in the BA window.
597          */
598         /* calculate offset in BA window */
599         off = IEEE80211_SEQ_SUB(rxseq, rap->rxa_start);
600         if (off < rap->rxa_wnd) {
601                 /*
602                  * Common case (hopefully): in the BA window.
603                  * Sec 9.10.7.6 a) (D2.04 p.118 line 47)
604                  */
605 #ifdef IEEE80211_AMPDU_AGE
606                 /* 
607                  * Check for frames sitting too long in the reorder queue.
608                  * This should only ever happen if frames are not delivered
609                  * without the sender otherwise notifying us (e.g. with a
610                  * BAR to move the window).  Typically this happens because
611                  * of vendor bugs that cause the sequence number to jump.
612                  * When this happens we get a gap in the reorder queue that
613                  * leaves frame sitting on the queue until they get pushed
614                  * out due to window moves.  When the vendor does not send
615                  * BAR this move only happens due to explicit packet sends
616                  *
617                  * NB: we only track the time of the oldest frame in the
618                  * reorder q; this means that if we flush we might push
619                  * frames that still "new"; if this happens then subsequent
620                  * frames will result in BA window moves which cost something
621                  * but is still better than a big throughput dip.
622                  */
623                 if (rap->rxa_qframes != 0) {
624                         /* XXX honor batimeout? */
625                         if (ticks - rap->rxa_age > ieee80211_ampdu_age) {
626                                 /*
627                                  * Too long since we received the first
628                                  * frame; flush the reorder buffer.
629                                  */
630                                 if (rap->rxa_qframes != 0) {
631                                         vap->iv_stats.is_ampdu_rx_age +=
632                                             rap->rxa_qframes;
633                                         ampdu_rx_flush(ni, rap);
634                                 }
635                                 rap->rxa_start = IEEE80211_SEQ_INC(rxseq);
636                                 return PROCESS;
637                         }
638                 } else {
639                         /*
640                          * First frame, start aging timer.
641                          */
642                         rap->rxa_age = ticks;
643                 }
644 #endif /* IEEE80211_AMPDU_AGE */
645                 /* save packet */
646                 if (rap->rxa_m[off] == NULL) {
647                         rap->rxa_m[off] = m;
648                         rap->rxa_qframes++;
649                         rap->rxa_qbytes += m->m_pkthdr.len;
650                         vap->iv_stats.is_ampdu_rx_reorder++;
651                 } else {
652                         IEEE80211_DISCARD_MAC(vap,
653                             IEEE80211_MSG_INPUT | IEEE80211_MSG_11N,
654                             ni->ni_macaddr, "a-mpdu duplicate",
655                             "seqno %u tid %u BA win <%u:%u>",
656                             rxseq, tid, rap->rxa_start,
657                             IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1));
658                         vap->iv_stats.is_rx_dup++;
659                         IEEE80211_NODE_STAT(ni, rx_dup);
660                         m_freem(m);
661                 }
662                 return CONSUMED;
663         }
664         if (off < IEEE80211_SEQ_BA_RANGE) {
665                 /*
666                  * Outside the BA window, but within range;
667                  * flush the reorder q and move the window.
668                  * Sec 9.10.7.6 b) (D2.04 p.118 line 60)
669                  */
670                 IEEE80211_NOTE(vap, IEEE80211_MSG_11N, ni,
671                     "move BA win <%u:%u> (%u frames) rxseq %u tid %u",
672                     rap->rxa_start,
673                     IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1),
674                     rap->rxa_qframes, rxseq, tid);
675                 vap->iv_stats.is_ampdu_rx_move++;
676 
677                 /*
678                  * The spec says to flush frames up to but not including:
679                  *      WinStart_B = rxseq - rap->rxa_wnd + 1
680                  * Then insert the frame or notify the caller to process
681                  * it immediately.  We can safely do this by just starting
682                  * over again because we know the frame will now be within
683                  * the BA window.
684                  */
685                 /* NB: rxa_wnd known to be >0 */
686                 ampdu_rx_flush_upto(ni, rap,
687                     IEEE80211_SEQ_SUB(rxseq, rap->rxa_wnd-1));
688                 goto again;
689         } else {
690                 /*
691                  * Outside the BA window and out of range; toss.
692                  * Sec 9.10.7.6 c) (D2.04 p.119 line 16)
693                  */
694                 IEEE80211_DISCARD_MAC(vap,
695                     IEEE80211_MSG_INPUT | IEEE80211_MSG_11N, ni->ni_macaddr,
696                     "MPDU", "BA win <%u:%u> (%u frames) rxseq %u tid %u%s",
697                     rap->rxa_start,
698                     IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1),
699                     rap->rxa_qframes, rxseq, tid,
700                     wh->i_fc[1] & IEEE80211_FC1_RETRY ? " (retransmit)" : "");
701                 vap->iv_stats.is_ampdu_rx_drop++;
702                 IEEE80211_NODE_STAT(ni, rx_drop);
703                 m_freem(m);
704                 return CONSUMED;
705         }
706 #undef CONSUMED
707 #undef PROCESS
708 #undef IEEE80211_FC0_QOSDATA
709 }
710 
711 /*
712  * Process a BAR ctl frame.  Dispatch all frames up to
713  * the sequence number of the frame.  If this frame is
714  * out of range it's discarded.
715  */
716 void
717 ieee80211_recv_bar(struct ieee80211_node *ni, struct mbuf *m0)
718 {
719         struct ieee80211vap *vap = ni->ni_vap;
720         struct ieee80211_frame_bar *wh;
721         struct ieee80211_rx_ampdu *rap;
722         ieee80211_seq rxseq;
723         int tid, off;
724 
725         if (!ieee80211_recv_bar_ena) {
726 #if 0
727                 IEEE80211_DISCARD_MAC(vap, IEEE80211_MSG_11N,
728                     ni->ni_macaddr, "BAR", "%s", "processing disabled");
729 #endif
730                 vap->iv_stats.is_ampdu_bar_bad++;
731                 return;
732         }
733         wh = mtod(m0, struct ieee80211_frame_bar *);
734         /* XXX check basic BAR */
735         tid = MS(le16toh(wh->i_ctl), IEEE80211_BAR_TID);
736         rap = &ni->ni_rx_ampdu[tid];
737         if ((rap->rxa_flags & IEEE80211_AGGR_XCHGPEND) == 0) {
738                 /*
739                  * No ADDBA request yet, don't touch.
740                  */
741                 IEEE80211_DISCARD_MAC(vap,
742                     IEEE80211_MSG_INPUT | IEEE80211_MSG_11N,
743                     ni->ni_macaddr, "BAR", "no BA stream, tid %u", tid);
744                 vap->iv_stats.is_ampdu_bar_bad++;
745                 return;
746         }
747         vap->iv_stats.is_ampdu_bar_rx++;
748         rxseq = le16toh(wh->i_seq) >> IEEE80211_SEQ_SEQ_SHIFT;
749         if (rxseq == rap->rxa_start)
750                 return;
751         /* calculate offset in BA window */
752         off = IEEE80211_SEQ_SUB(rxseq, rap->rxa_start);
753         if (off < IEEE80211_SEQ_BA_RANGE) {
754                 /*
755                  * Flush the reorder q up to rxseq and move the window.
756                  * Sec 9.10.7.6 a) (D2.04 p.119 line 22)
757                  */
758                 IEEE80211_NOTE(vap, IEEE80211_MSG_11N, ni,
759                     "BAR moves BA win <%u:%u> (%u frames) rxseq %u tid %u",
760                     rap->rxa_start,
761                     IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1),
762                     rap->rxa_qframes, rxseq, tid);
763                 vap->iv_stats.is_ampdu_bar_move++;
764 
765                 ampdu_rx_flush_upto(ni, rap, rxseq);
766                 if (off >= rap->rxa_wnd) {
767                         /*
768                          * BAR specifies a window start to the right of BA
769                          * window; we must move it explicitly since
770                          * ampdu_rx_flush_upto will not.
771                          */
772                         rap->rxa_start = rxseq;
773                 }
774         } else {
775                 /*
776                  * Out of range; toss.
777                  * Sec 9.10.7.6 b) (D2.04 p.119 line 41)
778                  */
779                 IEEE80211_DISCARD_MAC(vap,
780                     IEEE80211_MSG_INPUT | IEEE80211_MSG_11N, ni->ni_macaddr,
781                     "BAR", "BA win <%u:%u> (%u frames) rxseq %u tid %u%s",
782                     rap->rxa_start,
783                     IEEE80211_SEQ_ADD(rap->rxa_start, rap->rxa_wnd-1),
784                     rap->rxa_qframes, rxseq, tid,
785                     wh->i_fc[1] & IEEE80211_FC1_RETRY ? " (retransmit)" : "");
786                 vap->iv_stats.is_ampdu_bar_oow++;
787                 IEEE80211_NODE_STAT(ni, rx_drop);
788         }
789 }
790 
791 /*
792  * Setup HT-specific state in a node.  Called only
793  * when HT use is negotiated so we don't do extra
794  * work for temporary and/or legacy sta's.
795  */
796 void
797 ieee80211_ht_node_init(struct ieee80211_node *ni)
798 {
799         struct ieee80211_tx_ampdu *tap;
800         int ac;
801 
802         if (ni->ni_flags & IEEE80211_NODE_HT) {
803                 /*
804                  * Clean AMPDU state on re-associate.  This handles the case
805                  * where a station leaves w/o notifying us and then returns
806                  * before node is reaped for inactivity.
807                  */
808                 ieee80211_ht_node_cleanup(ni);
809         }
810         for (ac = 0; ac < WME_NUM_AC; ac++) {
811                 tap = &ni->ni_tx_ampdu[ac];
812                 tap->txa_ac = ac;
813                 tap->txa_ni = ni;
814                 /* NB: further initialization deferred */
815         }
816         ni->ni_flags |= IEEE80211_NODE_HT | IEEE80211_NODE_AMPDU;
817 }
818 
819 /*
820  * Cleanup HT-specific state in a node.  Called only
821  * when HT use has been marked.
822  */
823 void
824 ieee80211_ht_node_cleanup(struct ieee80211_node *ni)
825 {
826         int i;
827 
828         KASSERT(ni->ni_flags & IEEE80211_NODE_HT, ("not an HT node"));
829 
830         /* XXX optimize this */
831         for (i = 0; i < WME_NUM_AC; i++) {
832                 struct ieee80211_tx_ampdu *tap = &ni->ni_tx_ampdu[i];
833                 if (tap->txa_flags & IEEE80211_AGGR_SETUP)
834                         ampdu_tx_stop(tap);
835         }
836         for (i = 0; i < WME_NUM_TID; i++)
837                 ampdu_rx_stop(&ni->ni_rx_ampdu[i]);
838 
839         ni->ni_htcap = 0;
840         ni->ni_flags &= ~IEEE80211_NODE_HT_ALL;
841 }
842 
843 /*
844  * Age out HT resources for a station.
845  */
846 void
847 ieee80211_ht_node_age(struct ieee80211_node *ni)
848 {
849 #ifdef IEEE80211_AMPDU_AGE
850         struct ieee80211vap *vap = ni->ni_vap;
851         uint8_t tid;
852 #endif
853 
854         KASSERT(ni->ni_flags & IEEE80211_NODE_HT, ("not an HT sta"));
855 
856 #ifdef IEEE80211_AMPDU_AGE
857         for (tid = 0; tid < WME_NUM_TID; tid++) {
858                 struct ieee80211_rx_ampdu *rap;
859 
860                 rap = &ni->ni_rx_ampdu[tid];
861                 if ((rap->rxa_flags & IEEE80211_AGGR_XCHGPEND) == 0)
862                         continue;
863                 if (rap->rxa_qframes == 0)
864                         continue;
865                 /* 
866                  * Check for frames sitting too long in the reorder queue.
867                  * See above for more details on what's happening here.
868                  */
869                 /* XXX honor batimeout? */
870                 if (ticks - rap->rxa_age > ieee80211_ampdu_age) {
871                         /*
872                          * Too long since we received the first
873                          * frame; flush the reorder buffer.
874                          */
875                         vap->iv_stats.is_ampdu_rx_age += rap->rxa_qframes;
876                         ampdu_rx_flush(ni, rap);
877                 }
878         }
879 #endif /* IEEE80211_AMPDU_AGE */
880 }
881 
882 static struct ieee80211_channel *
883 findhtchan(struct ieee80211com *ic, struct ieee80211_channel *c, int htflags)
884 {
885         return ieee80211_find_channel(ic, c->ic_freq,
886             (c->ic_flags &~ IEEE80211_CHAN_HT) | htflags);
887 }
888 
889 /*
890  * Adjust a channel to be HT/non-HT according to the vap's configuration.
891  */
892 struct ieee80211_channel *
893 ieee80211_ht_adjust_channel(struct ieee80211com *ic,
894         struct ieee80211_channel *chan, int flags)
895 {
896         struct ieee80211_channel *c;
897 
898         if (flags & IEEE80211_FEXT_HT) {
899                 /* promote to HT if possible */
900                 if (flags & IEEE80211_FEXT_USEHT40) {
901                         if (!IEEE80211_IS_CHAN_HT40(chan)) {
902                                 /* NB: arbitrarily pick ht40+ over ht40- */
903                                 c = findhtchan(ic, chan, IEEE80211_CHAN_HT40U);
904                                 if (c == NULL)
905                                         c = findhtchan(ic, chan,
906                                                 IEEE80211_CHAN_HT40D);
907                                 if (c == NULL)
908                                         c = findhtchan(ic, chan,
909                                                 IEEE80211_CHAN_HT20);
910                                 if (c != NULL)
911                                         chan = c;
912                         }
913                 } else if (!IEEE80211_IS_CHAN_HT20(chan)) {
914                         c = findhtchan(ic, chan, IEEE80211_CHAN_HT20);
915                         if (c != NULL)
916                                 chan = c;
917                 }
918         } else if (IEEE80211_IS_CHAN_HT(chan)) {
919                 /* demote to legacy, HT use is disabled */
920                 c = ieee80211_find_channel(ic, chan->ic_freq,
921                     chan->ic_flags &~ IEEE80211_CHAN_HT);
922                 if (c != NULL)
923                         chan = c;
924         }
925         return chan;
926 }
927 
928 /*
929  * Setup HT-specific state for a legacy WDS peer.
930  */
931 void
932 ieee80211_ht_wds_init(struct ieee80211_node *ni)
933 {