xref: /freebsd/sys/net80211/ieee80211_tdma.c (revision 2e1417489338b971e5fd599ff48b5f65df9e8d3b)
1 /*-
2  * Copyright (c) 2007-2009 Sam Leffler, Errno Consulting
3  * Copyright (c) 2007-2009 Intel Corporation
4  * All rights reserved.
5  *
6  * Redistribution and use in source and binary forms, with or without
7  * modification, are permitted provided that the following conditions
8  * are met:
9  * 1. Redistributions of source code must retain the above copyright
10  *    notice, this list of conditions and the following disclaimer.
11  * 2. Redistributions in binary form must reproduce the above copyright
12  *    notice, this list of conditions and the following disclaimer in the
13  *    documentation and/or other materials provided with the distribution.
14  *
15  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
16  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
17  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
18  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
19  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
20  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
21  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
22  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
23  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
24  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25  */
26 
27 #include <sys/cdefs.h>
28 #ifdef __FreeBSD__
29 __FBSDID("$FreeBSD$");
30 #endif
31 
32 /*
33  * IEEE 802.11 TDMA mode support.
34  */
35 #include "opt_inet.h"
36 #include "opt_tdma.h"
37 #include "opt_wlan.h"
38 
39 #include <sys/param.h>
40 #include <sys/systm.h>
41 #include <sys/mbuf.h>
42 #include <sys/malloc.h>
43 #include <sys/kernel.h>
44 
45 #include <sys/socket.h>
46 #include <sys/sockio.h>
47 #include <sys/endian.h>
48 #include <sys/errno.h>
49 #include <sys/proc.h>
50 #include <sys/sysctl.h>
51 
52 #include <net/if.h>
53 #include <net/if_media.h>
54 #include <net/if_llc.h>
55 #include <net/ethernet.h>
56 
57 #include <net/bpf.h>
58 
59 #include <net80211/ieee80211_var.h>
60 #include <net80211/ieee80211_tdma.h>
61 #include <net80211/ieee80211_input.h>
62 
63 #ifndef TDMA_SLOTLEN_DEFAULT
64 #define	TDMA_SLOTLEN_DEFAULT	10*1000		/* 10ms */
65 #endif
66 #ifndef TDMA_SLOTCNT_DEFAULT
67 #define	TDMA_SLOTCNT_DEFAULT	2		/* 2x (pt-to-pt) */
68 #endif
69 #ifndef TDMA_BINTVAL_DEFAULT
70 #define	TDMA_BINTVAL_DEFAULT	5		/* 5x ~= 100TU beacon intvl */
71 #endif
72 #ifndef TDMA_TXRATE_11B_DEFAULT
73 #define	TDMA_TXRATE_11B_DEFAULT	2*11
74 #endif
75 #ifndef TDMA_TXRATE_11G_DEFAULT
76 #define	TDMA_TXRATE_11G_DEFAULT	2*24
77 #endif
78 #ifndef TDMA_TXRATE_11A_DEFAULT
79 #define	TDMA_TXRATE_11A_DEFAULT	2*24
80 #endif
81 #ifndef TDMA_TXRATE_TURBO_DEFAULT
82 #define	TDMA_TXRATE_TURBO_DEFAULT	2*24
83 #endif
84 #ifndef TDMA_TXRATE_HALF_DEFAULT
85 #define	TDMA_TXRATE_HALF_DEFAULT	2*12
86 #endif
87 #ifndef TDMA_TXRATE_QUARTER_DEFAULT
88 #define	TDMA_TXRATE_QUARTER_DEFAULT	2*6
89 #endif
90 #ifndef TDMA_TXRATE_11NA_DEFAULT
91 #define	TDMA_TXRATE_11NA_DEFAULT	(4 | IEEE80211_RATE_MCS)
92 #endif
93 #ifndef TDMA_TXRATE_11NG_DEFAULT
94 #define	TDMA_TXRATE_11NG_DEFAULT	(4 | IEEE80211_RATE_MCS)
95 #endif
96 
97 #define	TDMA_VERSION_VALID(_version) \
98 	(TDMA_VERSION_V2 <= (_version) && (_version) <= TDMA_VERSION)
99 #define	TDMA_SLOTCNT_VALID(_slotcnt) \
100 	(2 <= (_slotcnt) && (_slotcnt) <= TDMA_MAXSLOTS)
101 /* XXX magic constants */
102 #define	TDMA_SLOTLEN_VALID(_slotlen) \
103 	(2*100 <= (_slotlen) && (unsigned)(_slotlen) <= 0xfffff)
104 /* XXX probably should set a max */
105 #define	TDMA_BINTVAL_VALID(_bintval)	(1 <= (_bintval))
106 
107 /*
108  * This code is not prepared to handle more than 2 slots.
109  */
110 CTASSERT(TDMA_MAXSLOTS == 2);
111 
112 static void tdma_vdetach(struct ieee80211vap *vap);
113 static int tdma_newstate(struct ieee80211vap *, enum ieee80211_state, int);
114 static void tdma_beacon_miss(struct ieee80211vap *vap);
115 static void tdma_recv_mgmt(struct ieee80211_node *, struct mbuf *,
116 	int subtype, int rssi, int nf);
117 static int tdma_update(struct ieee80211vap *vap,
118 	const struct ieee80211_tdma_param *tdma, struct ieee80211_node *ni,
119 	int pickslot);
120 static int tdma_process_params(struct ieee80211_node *ni,
121 	const u_int8_t *ie, int rssi, int nf, const struct ieee80211_frame *wh);
122 
123 static void
124 settxparms(struct ieee80211vap *vap, enum ieee80211_phymode mode, int rate)
125 {
126 	vap->iv_txparms[mode].ucastrate = rate;
127 	vap->iv_txparms[mode].mcastrate = rate;
128 }
129 
130 static void
131 setackpolicy(struct ieee80211com *ic, int noack)
132 {
133 	struct ieee80211_wme_state *wme = &ic->ic_wme;
134 	int ac;
135 
136 	for (ac = 0; ac < WME_NUM_AC; ac++) {
137 		wme->wme_chanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
138 		wme->wme_wmeChanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
139 	}
140 }
141 
142 void
143 ieee80211_tdma_vattach(struct ieee80211vap *vap)
144 {
145 	struct ieee80211_tdma_state *ts;
146 
147 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
148 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
149 
150 	ts = (struct ieee80211_tdma_state *) malloc(
151 	     sizeof(struct ieee80211_tdma_state), M_80211_VAP, M_NOWAIT | M_ZERO);
152 	if (ts == NULL) {
153 		printf("%s: cannot allocate TDMA state block\n", __func__);
154 		/* NB: fall back to adhdemo mode */
155 		vap->iv_caps &= ~IEEE80211_C_TDMA;
156 		return;
157 	}
158 	/* NB: default configuration is passive so no beacons */
159 	ts->tdma_version = TDMA_VERSION;
160 	ts->tdma_slotlen = TDMA_SLOTLEN_DEFAULT;
161 	ts->tdma_slotcnt = TDMA_SLOTCNT_DEFAULT;
162 	ts->tdma_bintval = TDMA_BINTVAL_DEFAULT;
163 	ts->tdma_slot = 1;			/* passive operation */
164 
165 	/* setup default fixed rates */
166 	settxparms(vap, IEEE80211_MODE_11A, TDMA_TXRATE_11A_DEFAULT);
167 	settxparms(vap, IEEE80211_MODE_11B, TDMA_TXRATE_11B_DEFAULT);
168 	settxparms(vap, IEEE80211_MODE_11G, TDMA_TXRATE_11G_DEFAULT);
169 	settxparms(vap, IEEE80211_MODE_TURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
170 	settxparms(vap, IEEE80211_MODE_TURBO_G, TDMA_TXRATE_TURBO_DEFAULT);
171 	settxparms(vap, IEEE80211_MODE_STURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
172 	settxparms(vap, IEEE80211_MODE_11NA, TDMA_TXRATE_11NA_DEFAULT);
173 	settxparms(vap, IEEE80211_MODE_11NG, TDMA_TXRATE_11NG_DEFAULT);
174 	settxparms(vap, IEEE80211_MODE_HALF, TDMA_TXRATE_HALF_DEFAULT);
175 	settxparms(vap, IEEE80211_MODE_QUARTER, TDMA_TXRATE_QUARTER_DEFAULT);
176 
177 	setackpolicy(vap->iv_ic, 1);	/* disable ACK's */
178 
179 	ts->tdma_opdetach = vap->iv_opdetach;
180 	vap->iv_opdetach = tdma_vdetach;
181 	ts->tdma_newstate = vap->iv_newstate;
182 	vap->iv_newstate = tdma_newstate;
183 	vap->iv_bmiss = tdma_beacon_miss;
184 	ts->tdma_recv_mgmt = vap->iv_recv_mgmt;
185 	vap->iv_recv_mgmt = tdma_recv_mgmt;
186 
187 	vap->iv_tdma = ts;
188 }
189 
190 static void
191 tdma_vdetach(struct ieee80211vap *vap)
192 {
193 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
194 
195 	if (ts == NULL) {
196 		/* NB: should not have touched any ic state */
197 		return;
198 	}
199 	ts->tdma_opdetach(vap);
200 	free(vap->iv_tdma, M_80211_VAP);
201 	vap->iv_tdma = NULL;
202 
203 	setackpolicy(vap->iv_ic, 0);	/* enable ACK's */
204 }
205 
206 static void
207 sta_leave(void *arg, struct ieee80211_node *ni)
208 {
209 	struct ieee80211vap *vap = arg;
210 
211 	if (ni->ni_vap == vap && ni != vap->iv_bss)
212 		ieee80211_node_leave(ni);
213 }
214 
215 /*
216  * TDMA state machine handler.
217  */
218 static int
219 tdma_newstate(struct ieee80211vap *vap, enum ieee80211_state nstate, int arg)
220 {
221 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
222 	struct ieee80211com *ic = vap->iv_ic;
223 	enum ieee80211_state ostate;
224 	int status;
225 
226 	IEEE80211_LOCK_ASSERT(ic);
227 
228 	ostate = vap->iv_state;
229 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_STATE, "%s: %s -> %s (%d)\n",
230 	    __func__, ieee80211_state_name[ostate],
231 	    ieee80211_state_name[nstate], arg);
232 
233 	if (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS)
234 		callout_stop(&vap->iv_swbmiss);
235 	if (nstate == IEEE80211_S_SCAN &&
236 	    (ostate == IEEE80211_S_INIT || ostate == IEEE80211_S_RUN) &&
237 	    ts->tdma_slot != 0) {
238 		/*
239 		 * Override adhoc behaviour when operating as a slave;
240 		 * we need to scan even if the channel is locked.
241 		 */
242 		vap->iv_state = nstate;			/* state transition */
243 		ieee80211_cancel_scan(vap);		/* background scan */
244 		if (ostate == IEEE80211_S_RUN) {
245 			/* purge station table; entries are stale */
246 			ieee80211_iterate_nodes(&ic->ic_sta, sta_leave, vap);
247 		}
248 		if (vap->iv_flags_ext & IEEE80211_FEXT_SCANREQ) {
249 			ieee80211_check_scan(vap,
250 			    vap->iv_scanreq_flags,
251 			    vap->iv_scanreq_duration,
252 			    vap->iv_scanreq_mindwell,
253 			    vap->iv_scanreq_maxdwell,
254 			    vap->iv_scanreq_nssid, vap->iv_scanreq_ssid);
255 			vap->iv_flags_ext &= ~IEEE80211_FEXT_SCANREQ;
256 		} else
257 			ieee80211_check_scan_current(vap);
258 		status = 0;
259 	} else {
260 		status = ts->tdma_newstate(vap, nstate, arg);
261 	}
262 	if (status == 0 &&
263 	    nstate == IEEE80211_S_RUN && ostate != IEEE80211_S_RUN &&
264 	    (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS) &&
265 	    ts->tdma_slot != 0 &&
266 	    vap->iv_des_chan == IEEE80211_CHAN_ANYC) {
267 		/*
268 		 * Start s/w beacon miss timer for slave devices w/o
269 		 * hardware support.  Note we do this only if we're
270 		 * not locked to a channel (i.e. roam to follow the
271 		 * master). The 2x is a fudge for our doing this in
272 		 * software.
273 		 */
274 		vap->iv_swbmiss_period = IEEE80211_TU_TO_TICKS(
275 		    2 * vap->iv_bmissthreshold * ts->tdma_bintval *
276 		    ((ts->tdma_slotcnt * ts->tdma_slotlen) / 1024));
277 		vap->iv_swbmiss_count = 0;
278 		callout_reset(&vap->iv_swbmiss, vap->iv_swbmiss_period,
279 			ieee80211_swbmiss, vap);
280 	}
281 	return status;
282 }
283 
284 static void
285 tdma_beacon_miss(struct ieee80211vap *vap)
286 {
287 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
288 
289 	IEEE80211_LOCK_ASSERT(vap->iv_ic);
290 
291 	KASSERT((vap->iv_ic->ic_flags & IEEE80211_F_SCAN) == 0, ("scanning"));
292 	KASSERT(vap->iv_state == IEEE80211_S_RUN,
293 	    ("wrong state %d", vap->iv_state));
294 
295 	IEEE80211_DPRINTF(vap,
296 		IEEE80211_MSG_STATE | IEEE80211_MSG_TDMA | IEEE80211_MSG_DEBUG,
297 		"beacon miss, mode %u state %s\n",
298 		vap->iv_opmode, ieee80211_state_name[vap->iv_state]);
299 
300 	callout_stop(&vap->iv_swbmiss);
301 
302 	if (ts->tdma_peer != NULL) {	/* XXX? can this be null? */
303 		ieee80211_notify_node_leave(vap->iv_bss);
304 		ts->tdma_peer = NULL;
305 		/*
306 		 * Treat beacon miss like an associate failure wrt the
307 		 * scan policy; this forces the entry in the scan cache
308 		 * to be ignored after several tries.
309 		 */
310 		ieee80211_scan_assoc_fail(vap, vap->iv_bss->ni_macaddr,
311 		    IEEE80211_STATUS_TIMEOUT);
312 	}
313 #if 0
314 	ts->tdma_inuse = 0;		/* clear slot usage */
315 #endif
316 	ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
317 }
318 
319 static void
320 tdma_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m0,
321 	int subtype, int rssi, int nf)
322 {
323 	struct ieee80211com *ic = ni->ni_ic;
324 	struct ieee80211vap *vap = ni->ni_vap;
325 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
326 
327 	if (subtype == IEEE80211_FC0_SUBTYPE_BEACON &&
328 	    (ic->ic_flags & IEEE80211_F_SCAN) == 0) {
329 		struct ieee80211_frame *wh = mtod(m0, struct ieee80211_frame *);
330 		struct ieee80211_scanparams scan;
331 
332 		if (ieee80211_parse_beacon(ni, m0, &scan) != 0)
333 			return;
334 		if (scan.tdma == NULL) {
335 			/*
336 			 * TDMA stations must beacon a TDMA ie; ignore
337 			 * any other station.
338 			 * XXX detect overlapping bss and change channel
339 			 */
340 			IEEE80211_DISCARD(vap,
341 			    IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
342 			    wh, ieee80211_mgt_subtype_name[subtype >>
343 				IEEE80211_FC0_SUBTYPE_SHIFT],
344 			    "%s", "no TDMA ie");
345 			vap->iv_stats.is_rx_mgtdiscard++;
346 			return;
347 		}
348 		if (ni == vap->iv_bss &&
349 		    !IEEE80211_ADDR_EQ(wh->i_addr2, ni->ni_macaddr)) {
350 			/*
351 			 * Fake up a node for this newly
352 			 * discovered member of the IBSS.
353 			 */
354 			ni = ieee80211_add_neighbor(vap, wh, &scan);
355 			if (ni == NULL) {
356 				/* NB: stat kept for alloc failure */
357 				return;
358 			}
359 		}
360 		/*
361 		 * Check for state updates.
362 		 */
363 		if (IEEE80211_ADDR_EQ(wh->i_addr3, ni->ni_bssid)) {
364 			/*
365 			 * Count frame now that we know it's to be processed.
366 			 */
367 			vap->iv_stats.is_rx_beacon++;
368 			IEEE80211_NODE_STAT(ni, rx_beacons);
369 			/*
370 			 * Record tsf of last beacon.  NB: this must be
371 			 * done before calling tdma_process_params
372 			 * as deeper routines reference it.
373 			 */
374 			memcpy(&ni->ni_tstamp.data, scan.tstamp,
375 				sizeof(ni->ni_tstamp.data));
376 			/*
377 			 * Count beacon frame for s/w bmiss handling.
378 			 */
379 			vap->iv_swbmiss_count++;
380 			/*
381 			 * Process tdma ie.  The contents are used to sync
382 			 * the slot timing, reconfigure the bss, etc.
383 			 */
384 			(void) tdma_process_params(ni, scan.tdma, rssi, nf, wh);
385 			return;
386 		}
387 		/*
388 		 * NB: defer remaining work to the adhoc code; this causes
389 		 *     2x parsing of the frame but should happen infrequently
390 		 */
391 	}
392 	ts->tdma_recv_mgmt(ni, m0, subtype, rssi, nf);
393 }
394 
395 /*
396  * Update TDMA state on receipt of a beacon frame with
397  * a TDMA information element.  The sender's identity
398  * is provided so we can track who our peer is.  If pickslot
399  * is non-zero we scan the slot allocation state in the ie
400  * to locate a free slot for our use.
401  */
402 static int
403 tdma_update(struct ieee80211vap *vap, const struct ieee80211_tdma_param *tdma,
404 	struct ieee80211_node *ni, int pickslot)
405 {
406 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
407 	int slot, slotlen, update;
408 
409 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
410 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
411 
412 	update = 0;
413 	if (tdma->tdma_slotcnt != ts->tdma_slotcnt) {
414 		if (!TDMA_SLOTCNT_VALID(tdma->tdma_slotcnt)) {
415 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
416 				printf("%s: bad slot cnt %u\n",
417 				    __func__, tdma->tdma_slotcnt);
418 			return 0;
419 		}
420 		update |= TDMA_UPDATE_SLOTCNT;
421  	}
422 	slotlen = le16toh(tdma->tdma_slotlen) * 100;
423 	if (slotlen != ts->tdma_slotlen) {
424 		if (!TDMA_SLOTLEN_VALID(slotlen)) {
425 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
426 				printf("%s: bad slot len %u\n",
427 				    __func__, slotlen);
428 			return 0;
429 		}
430 		update |= TDMA_UPDATE_SLOTLEN;
431  	}
432 	if (tdma->tdma_bintval != ts->tdma_bintval) {
433 		if (!TDMA_BINTVAL_VALID(tdma->tdma_bintval)) {
434 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
435 				printf("%s: bad beacon interval %u\n",
436 				    __func__, tdma->tdma_bintval);
437 			return 0;
438 		}
439 		update |= TDMA_UPDATE_BINTVAL;
440  	}
441 	slot = ts->tdma_slot;
442 	if (pickslot) {
443 		/*
444 		 * Pick unoccupied slot.  Note we never choose slot 0.
445 		 */
446 		for (slot = tdma->tdma_slotcnt-1; slot > 0; slot--)
447 			if (isclr(tdma->tdma_inuse, slot))
448 				break;
449 		if (slot <= 0) {
450 			printf("%s: no free slot, slotcnt %u inuse: 0x%x\n",
451 				__func__, tdma->tdma_slotcnt,
452 				tdma->tdma_inuse[0]);
453 			/* XXX need to do something better */
454 			return 0;
455 		}
456 		if (slot != ts->tdma_slot)
457 			update |= TDMA_UPDATE_SLOT;
458 	}
459 	if (ni != ts->tdma_peer) {
460 		/* update everything */
461 		update = TDMA_UPDATE_SLOT
462 		       | TDMA_UPDATE_SLOTCNT
463 		       | TDMA_UPDATE_SLOTLEN
464 		       | TDMA_UPDATE_BINTVAL;
465 	}
466 
467 	if (update) {
468 		/*
469 		 * New/changed parameters; update runtime state.
470 		 */
471 		/* XXX overwrites user parameters */
472 		if (update & TDMA_UPDATE_SLOTCNT)
473 			ts->tdma_slotcnt = tdma->tdma_slotcnt;
474 		if (update & TDMA_UPDATE_SLOTLEN)
475 			ts->tdma_slotlen = slotlen;
476 		if (update & TDMA_UPDATE_SLOT)
477 			ts->tdma_slot = slot;
478 		if (update & TDMA_UPDATE_BINTVAL)
479 			ts->tdma_bintval = tdma->tdma_bintval;
480 		/* mark beacon to be updated before next xmit */
481 		ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
482 
483 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
484 		    "%s: slot %u slotcnt %u slotlen %u us bintval %u\n",
485 		    __func__, ts->tdma_slot, ts->tdma_slotcnt,
486 		    ts->tdma_slotlen, ts->tdma_bintval);
487 	}
488 	/*
489 	 * Notify driver.  Note we can be called before
490 	 * entering RUN state if we scanned and are
491 	 * joining an existing bss.  In that case do not
492 	 * call the driver because not all necessary state
493 	 * has been setup.  The next beacon will dtrt.
494 	 */
495 	if (vap->iv_state == IEEE80211_S_RUN)
496 		vap->iv_ic->ic_tdma_update(ni, tdma, update);
497 	/*
498 	 * Dispatch join event on first beacon from new master.
499 	 */
500 	if (ts->tdma_peer != ni) {
501 		if (ts->tdma_peer != NULL)
502 			ieee80211_notify_node_leave(vap->iv_bss);
503 		ieee80211_notify_node_join(ni, 1);
504 		/* NB: no reference, we just use the address */
505 		ts->tdma_peer = ni;
506 	}
507 	return 1;
508 }
509 
510 /*
511  * Process received TDMA parameters.
512  */
513 static int
514 tdma_process_params(struct ieee80211_node *ni, const u_int8_t *ie,
515 	int rssi, int nf, const struct ieee80211_frame *wh)
516 {
517 	struct ieee80211vap *vap = ni->ni_vap;
518 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
519 	const struct ieee80211_tdma_param *tdma =
520 		(const struct ieee80211_tdma_param *) ie;
521 	u_int len = ie[1];
522 
523 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
524 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
525 
526 	if (len < sizeof(*tdma) - 2) {
527 		IEEE80211_DISCARD_IE(vap,
528 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
529 		    wh, "tdma", "too short, len %u", len);
530 		return IEEE80211_REASON_IE_INVALID;
531 	}
532 	if (tdma->tdma_version != ts->tdma_version) {
533 		IEEE80211_DISCARD_IE(vap,
534 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
535 		    wh, "tdma", "bad version %u (ours %u)",
536 		    tdma->tdma_version, ts->tdma_version);
537 		return IEEE80211_REASON_IE_INVALID;
538 	}
539  	/*
540 	 * NB: ideally we'd check against tdma_slotcnt, but that
541 	 * would require extra effort so do this easy check that
542 	 * covers the work below; more stringent checks are done
543 	 * before we make more extensive use of the ie contents.
544 	 */
545 	if (tdma->tdma_slot >= TDMA_MAXSLOTS) {
546 		IEEE80211_DISCARD_IE(vap,
547 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
548 		    wh, "tdma", "invalid slot %u", tdma->tdma_slot);
549 		return IEEE80211_REASON_IE_INVALID;
550 	}
551 	/*
552 	 * Can reach here while scanning, update
553 	 * operational state only in RUN state.
554 	 */
555 	if (vap->iv_state == IEEE80211_S_RUN) {
556 		if (tdma->tdma_slot != ts->tdma_slot &&
557 		    isclr(ts->tdma_inuse, tdma->tdma_slot)) {
558 			IEEE80211_NOTE(vap, IEEE80211_MSG_TDMA, ni,
559 			    "discovered in slot %u", tdma->tdma_slot);
560 			setbit(ts->tdma_inuse, tdma->tdma_slot);
561 			/* XXX dispatch event only when operating as master */
562 			if (ts->tdma_slot == 0)
563 				ieee80211_notify_node_join(ni, 1);
564 		}
565 		setbit(ts->tdma_active, tdma->tdma_slot);
566 		if (tdma->tdma_slot == ts->tdma_slot-1) {
567 			/*
568 			 * Slave tsf synchronization to station
569 			 * just before us in the schedule. The driver
570 			 * is responsible for copying the timestamp
571 			 * of the received beacon into our beacon
572 			 * frame so the sender can calculate round
573 			 * trip time.  We cannot do that here because
574 			 * we don't know how to update our beacon frame.
575 			 */
576 			(void) tdma_update(vap, tdma, ni, 0);
577 			/* XXX reschedule swbmiss timer on parameter change */
578 		} else if (tdma->tdma_slot == ts->tdma_slot+1) {
579 			uint64_t tstamp;
580 #if 0
581 			uint32_t rstamp = (uint32_t) le64toh(rs->tsf);
582 			int32_t rtt;
583 #endif
584 			/*
585 			 * Use returned timstamp to calculate the
586 			 * roundtrip time.
587 			 */
588 			memcpy(&tstamp, tdma->tdma_tstamp, 8);
589 #if 0
590 			/* XXX use only 15 bits of rstamp */
591 			rtt = rstamp - (le64toh(tstamp) & 0x7fff);
592 			if (rtt < 0)
593 				rtt += 0x7fff;
594 			/* XXX hack to quiet normal use */
595 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_DOT1X,
596 			    "tdma rtt %5u [rstamp %5u tstamp %llu]\n",
597 			    rtt, rstamp,
598 			    (unsigned long long) le64toh(tstamp));
599 #endif
600 		} else if (tdma->tdma_slot == ts->tdma_slot &&
601 		    le64toh(ni->ni_tstamp.tsf) > vap->iv_bss->ni_tstamp.tsf) {
602 			/*
603 			 * Station using the same slot as us and has
604 			 * been around longer than us; we must move.
605 			 * Note this can happen if stations do not
606 			 * see each other while scanning.
607 			 */
608 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
609 			    "slot %u collision rxtsf %llu tsf %llu\n",
610 			    tdma->tdma_slot,
611 			    (unsigned long long) le64toh(ni->ni_tstamp.tsf),
612 			    vap->iv_bss->ni_tstamp.tsf);
613 			setbit(ts->tdma_inuse, tdma->tdma_slot);
614 
615 			(void) tdma_update(vap, tdma, ni, 1);
616 		}
617 	}
618 	return 0;
619 }
620 
621 int
622 ieee80211_tdma_getslot(struct ieee80211vap *vap)
623 {
624 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
625 
626 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
627 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
628 	return ts->tdma_slot;
629 }
630 
631 /*
632  * Parse a TDMA ie on station join and use it to setup node state.
633  */
634 void
635 ieee80211_parse_tdma(struct ieee80211_node *ni, const uint8_t *ie)
636 {
637 	struct ieee80211vap *vap = ni->ni_vap;
638 
639 	if (vap->iv_caps & IEEE80211_C_TDMA) {
640 		const struct ieee80211_tdma_param *tdma =
641 		    (const struct ieee80211_tdma_param *)ie;
642 		struct ieee80211_tdma_state *ts = vap->iv_tdma;
643 		/*
644 		 * Adopt TDMA configuration when joining an
645 		 * existing network.
646 		 */
647 		setbit(ts->tdma_inuse, tdma->tdma_slot);
648 		(void) tdma_update(vap, tdma, ni, 1);
649 		/*
650 		 * Propagate capabilities based on the local
651 		 * configuration and the remote station's advertised
652 		 * capabilities. In particular this permits us to
653 		 * enable use of QoS to disable ACK's.
654 		 */
655 		if ((vap->iv_flags & IEEE80211_F_WME) &&
656 		    ni->ni_ies.wme_ie != NULL)
657 			ni->ni_flags |= IEEE80211_NODE_QOS;
658 	}
659 }
660 
661 #define	TDMA_OUI_BYTES		0x00, 0x03, 0x7f
662 /*
663  * Add a TDMA parameters element to a frame.
664  */
665 uint8_t *
666 ieee80211_add_tdma(uint8_t *frm, struct ieee80211vap *vap)
667 {
668 #define	ADDSHORT(frm, v) do {			\
669 	frm[0] = (v) & 0xff;			\
670 	frm[1] = (v) >> 8;			\
671 	frm += 2;				\
672 } while (0)
673 	static const struct ieee80211_tdma_param param = {
674 		.tdma_id	= IEEE80211_ELEMID_VENDOR,
675 		.tdma_len	= sizeof(struct ieee80211_tdma_param) - 2,
676 		.tdma_oui	= { TDMA_OUI_BYTES },
677 		.tdma_type	= TDMA_OUI_TYPE,
678 		.tdma_subtype	= TDMA_SUBTYPE_PARAM,
679 		.tdma_version	= TDMA_VERSION,
680 	};
681 	const struct ieee80211_tdma_state *ts = vap->iv_tdma;
682 	uint16_t slotlen;
683 
684 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
685 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
686 
687 	memcpy(frm, &param, sizeof(param));
688 	frm += __offsetof(struct ieee80211_tdma_param, tdma_slot);
689 	*frm++ = ts->tdma_slot;
690 	*frm++ = ts->tdma_slotcnt;
691 	/* NB: convert units to fit in 16-bits */
692 	slotlen = ts->tdma_slotlen / 100;	/* 100us units */
693 	ADDSHORT(frm, slotlen);
694 	*frm++ = ts->tdma_bintval;
695 	*frm++ = ts->tdma_inuse[0];
696 	frm += 10;				/* pad+timestamp */
697 	return frm;
698 #undef ADDSHORT
699 }
700 #undef TDMA_OUI_BYTES
701 
702 /*
703  * Update TDMA state at TBTT.
704  */
705 void
706 ieee80211_tdma_update_beacon(struct ieee80211vap *vap,
707 	struct ieee80211_beacon_offsets *bo)
708 {
709 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
710 
711 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
712 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
713 
714 	if (isset(bo->bo_flags,  IEEE80211_BEACON_TDMA)) {
715 		(void) ieee80211_add_tdma(bo->bo_tdma, vap);
716 		clrbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
717 	}
718 	if (ts->tdma_slot != 0)		/* only on master */
719 		return;
720 	if (ts->tdma_count <= 0) {
721 		/*
722 		 * Time to update the mask of active/inuse stations.
723 		 * We track stations that we've received a beacon
724 		 * frame from and update this mask periodically.
725 		 * This allows us to miss a few beacons before marking
726 		 * a slot free for re-use.
727 		 */
728 		ts->tdma_inuse[0] = ts->tdma_active[0];
729 		ts->tdma_active[0] = 0x01;
730 		/* update next time 'round */
731 		/* XXX use notify framework */
732 		setbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
733 		/* NB: use s/w beacon miss threshold; may be too high */
734 		ts->tdma_count = vap->iv_bmissthreshold-1;
735 	} else
736 		ts->tdma_count--;
737 }
738 
739 static int
740 tdma_ioctl_get80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
741 {
742 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
743 
744 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
745 		return EOPNOTSUPP;
746 
747 	switch (ireq->i_type) {
748 	case IEEE80211_IOC_TDMA_SLOT:
749 		ireq->i_val = ts->tdma_slot;
750 		break;
751 	case IEEE80211_IOC_TDMA_SLOTCNT:
752 		ireq->i_val = ts->tdma_slotcnt;
753 		break;
754 	case IEEE80211_IOC_TDMA_SLOTLEN:
755 		ireq->i_val = ts->tdma_slotlen;
756 		break;
757 	case IEEE80211_IOC_TDMA_BINTERVAL:
758 		ireq->i_val = ts->tdma_bintval;
759 		break;
760 	default:
761 		return ENOSYS;
762 	}
763 	return 0;
764 }
765 IEEE80211_IOCTL_GET(tdma, tdma_ioctl_get80211);
766 
767 static int
768 tdma_ioctl_set80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
769 {
770 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
771 
772 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
773 		return EOPNOTSUPP;
774 
775 	switch (ireq->i_type) {
776 	case IEEE80211_IOC_TDMA_SLOT:
777 		if (!(0 <= ireq->i_val && ireq->i_val <= ts->tdma_slotcnt))
778 			return EINVAL;
779 		if (ireq->i_val != ts->tdma_slot) {
780 			ts->tdma_slot = ireq->i_val;
781 			goto restart;
782 		}
783 		break;
784 	case IEEE80211_IOC_TDMA_SLOTCNT:
785 		if (!TDMA_SLOTCNT_VALID(ireq->i_val))
786 			return EINVAL;
787 		if (ireq->i_val != ts->tdma_slotcnt) {
788 			ts->tdma_slotcnt = ireq->i_val;
789 			goto restart;
790 		}
791 		break;
792 	case IEEE80211_IOC_TDMA_SLOTLEN:
793 		/*
794 		 * XXX
795 		 * 150 insures at least 1/8 TU
796 		 * 0xfffff is the max duration for bursting
797 		 * (implict by way of 16-bit data type for i_val)
798 		 */
799 		if (!TDMA_SLOTLEN_VALID(ireq->i_val))
800 			return EINVAL;
801 		if (ireq->i_val != ts->tdma_slotlen) {
802 			ts->tdma_slotlen = ireq->i_val;
803 			goto restart;
804 		}
805 		break;
806 	case IEEE80211_IOC_TDMA_BINTERVAL:
807 		if (!TDMA_BINTVAL_VALID(ireq->i_val))
808 			return EINVAL;
809 		if (ireq->i_val != ts->tdma_bintval) {
810 			ts->tdma_bintval = ireq->i_val;
811 			goto restart;
812 		}
813 		break;
814 	default:
815 		return ENOSYS;
816 	}
817 	return 0;
818 restart:
819 	ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
820 	return ERESTART;
821 }
822 IEEE80211_IOCTL_SET(tdma, tdma_ioctl_set80211);
823