xref: /freebsd/sys/net80211/ieee80211_tdma.c (revision bdd1243df58e60e85101c09001d9812a789b6bc4)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause
3  *
4  * Copyright (c) 2007-2009 Sam Leffler, Errno Consulting
5  * Copyright (c) 2007-2009 Intel Corporation
6  * All rights reserved.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 #ifdef __FreeBSD__
31 __FBSDID("$FreeBSD$");
32 #endif
33 
34 /*
35  * IEEE 802.11 TDMA mode support.
36  */
37 #include "opt_inet.h"
38 #include "opt_tdma.h"
39 #include "opt_wlan.h"
40 
41 #ifdef	IEEE80211_SUPPORT_TDMA
42 
43 #include <sys/param.h>
44 #include <sys/systm.h>
45 #include <sys/mbuf.h>
46 #include <sys/malloc.h>
47 #include <sys/kernel.h>
48 
49 #include <sys/socket.h>
50 #include <sys/sockio.h>
51 #include <sys/endian.h>
52 #include <sys/errno.h>
53 #include <sys/proc.h>
54 #include <sys/sysctl.h>
55 
56 #include <net/if.h>
57 #include <net/if_media.h>
58 #include <net/if_llc.h>
59 #include <net/ethernet.h>
60 
61 #include <net/bpf.h>
62 
63 #include <net80211/ieee80211_var.h>
64 #include <net80211/ieee80211_tdma.h>
65 #include <net80211/ieee80211_input.h>
66 
67 #ifndef TDMA_SLOTLEN_DEFAULT
68 #define	TDMA_SLOTLEN_DEFAULT	10*1000		/* 10ms */
69 #endif
70 #ifndef TDMA_SLOTCNT_DEFAULT
71 #define	TDMA_SLOTCNT_DEFAULT	2		/* 2x (pt-to-pt) */
72 #endif
73 #ifndef TDMA_BINTVAL_DEFAULT
74 #define	TDMA_BINTVAL_DEFAULT	5		/* 5x ~= 100TU beacon intvl */
75 #endif
76 #ifndef TDMA_TXRATE_11B_DEFAULT
77 #define	TDMA_TXRATE_11B_DEFAULT	2*11
78 #endif
79 #ifndef TDMA_TXRATE_11G_DEFAULT
80 #define	TDMA_TXRATE_11G_DEFAULT	2*24
81 #endif
82 #ifndef TDMA_TXRATE_11A_DEFAULT
83 #define	TDMA_TXRATE_11A_DEFAULT	2*24
84 #endif
85 #ifndef TDMA_TXRATE_TURBO_DEFAULT
86 #define	TDMA_TXRATE_TURBO_DEFAULT	2*24
87 #endif
88 #ifndef TDMA_TXRATE_HALF_DEFAULT
89 #define	TDMA_TXRATE_HALF_DEFAULT	2*12
90 #endif
91 #ifndef TDMA_TXRATE_QUARTER_DEFAULT
92 #define	TDMA_TXRATE_QUARTER_DEFAULT	2*6
93 #endif
94 #ifndef TDMA_TXRATE_11NA_DEFAULT
95 #define	TDMA_TXRATE_11NA_DEFAULT	(4 | IEEE80211_RATE_MCS)
96 #endif
97 #ifndef TDMA_TXRATE_11NG_DEFAULT
98 #define	TDMA_TXRATE_11NG_DEFAULT	(4 | IEEE80211_RATE_MCS)
99 #endif
100 
101 #define	TDMA_VERSION_VALID(_version) \
102 	(TDMA_VERSION_V2 <= (_version) && (_version) <= TDMA_VERSION)
103 #define	TDMA_SLOTCNT_VALID(_slotcnt) \
104 	(2 <= (_slotcnt) && (_slotcnt) <= TDMA_MAXSLOTS)
105 /* XXX magic constants */
106 #define	TDMA_SLOTLEN_VALID(_slotlen) \
107 	(2*100 <= (_slotlen) && (unsigned)(_slotlen) <= 0xfffff)
108 /* XXX probably should set a max */
109 #define	TDMA_BINTVAL_VALID(_bintval)	(1 <= (_bintval))
110 
111 /*
112  * This code is not prepared to handle more than 2 slots.
113  */
114 CTASSERT(TDMA_MAXSLOTS == 2);
115 
116 static void tdma_vdetach(struct ieee80211vap *vap);
117 static int tdma_newstate(struct ieee80211vap *, enum ieee80211_state, int);
118 static void tdma_beacon_miss(struct ieee80211vap *vap);
119 static void tdma_recv_mgmt(struct ieee80211_node *, struct mbuf *,
120 	int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf);
121 static int tdma_update(struct ieee80211vap *vap,
122 	const struct ieee80211_tdma_param *tdma, struct ieee80211_node *ni,
123 	int pickslot);
124 static int tdma_process_params(struct ieee80211_node *ni,
125 	const u_int8_t *ie, int rssi, int nf, const struct ieee80211_frame *wh);
126 
127 static void
128 settxparms(struct ieee80211vap *vap, enum ieee80211_phymode mode, int rate)
129 {
130 	if (isclr(vap->iv_ic->ic_modecaps, mode))
131 		return;
132 
133 	vap->iv_txparms[mode].ucastrate = rate;
134 	vap->iv_txparms[mode].mcastrate = rate;
135 }
136 
137 static void
138 setackpolicy(struct ieee80211com *ic, int noack)
139 {
140 	struct ieee80211_wme_state *wme = &ic->ic_wme;
141 	int ac;
142 
143 	for (ac = 0; ac < WME_NUM_AC; ac++) {
144 		wme->wme_chanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
145 		wme->wme_wmeChanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
146 	}
147 }
148 
149 void
150 ieee80211_tdma_vattach(struct ieee80211vap *vap)
151 {
152 	struct ieee80211_tdma_state *ts;
153 
154 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
155 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
156 
157 	ts = (struct ieee80211_tdma_state *) IEEE80211_MALLOC(
158 	     sizeof(struct ieee80211_tdma_state), M_80211_VAP,
159 	     IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
160 	if (ts == NULL) {
161 		printf("%s: cannot allocate TDMA state block\n", __func__);
162 		/* NB: fall back to adhdemo mode */
163 		vap->iv_caps &= ~IEEE80211_C_TDMA;
164 		return;
165 	}
166 	/* NB: default configuration is passive so no beacons */
167 	ts->tdma_version = TDMA_VERSION;
168 	ts->tdma_slotlen = TDMA_SLOTLEN_DEFAULT;
169 	ts->tdma_slotcnt = TDMA_SLOTCNT_DEFAULT;
170 	ts->tdma_bintval = TDMA_BINTVAL_DEFAULT;
171 	ts->tdma_slot = 1;			/* passive operation */
172 
173 	/* setup default fixed rates */
174 	settxparms(vap, IEEE80211_MODE_11A, TDMA_TXRATE_11A_DEFAULT);
175 	settxparms(vap, IEEE80211_MODE_11B, TDMA_TXRATE_11B_DEFAULT);
176 	settxparms(vap, IEEE80211_MODE_11G, TDMA_TXRATE_11G_DEFAULT);
177 	settxparms(vap, IEEE80211_MODE_TURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
178 	settxparms(vap, IEEE80211_MODE_TURBO_G, TDMA_TXRATE_TURBO_DEFAULT);
179 	settxparms(vap, IEEE80211_MODE_STURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
180 	settxparms(vap, IEEE80211_MODE_11NA, TDMA_TXRATE_11NA_DEFAULT);
181 	settxparms(vap, IEEE80211_MODE_11NG, TDMA_TXRATE_11NG_DEFAULT);
182 	settxparms(vap, IEEE80211_MODE_HALF, TDMA_TXRATE_HALF_DEFAULT);
183 	settxparms(vap, IEEE80211_MODE_QUARTER, TDMA_TXRATE_QUARTER_DEFAULT);
184 	settxparms(vap, IEEE80211_MODE_VHT_2GHZ, TDMA_TXRATE_11NG_DEFAULT);
185 	settxparms(vap, IEEE80211_MODE_VHT_5GHZ, TDMA_TXRATE_11NA_DEFAULT);
186 
187 	setackpolicy(vap->iv_ic, 1);	/* disable ACK's */
188 
189 	ts->tdma_opdetach = vap->iv_opdetach;
190 	vap->iv_opdetach = tdma_vdetach;
191 	ts->tdma_newstate = vap->iv_newstate;
192 	vap->iv_newstate = tdma_newstate;
193 	vap->iv_bmiss = tdma_beacon_miss;
194 	ts->tdma_recv_mgmt = vap->iv_recv_mgmt;
195 	vap->iv_recv_mgmt = tdma_recv_mgmt;
196 
197 	vap->iv_tdma = ts;
198 }
199 
200 static void
201 tdma_vdetach(struct ieee80211vap *vap)
202 {
203 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
204 
205 	if (ts == NULL) {
206 		/* NB: should not have touched any ic state */
207 		return;
208 	}
209 	ts->tdma_opdetach(vap);
210 	IEEE80211_FREE(vap->iv_tdma, M_80211_VAP);
211 	vap->iv_tdma = NULL;
212 
213 	setackpolicy(vap->iv_ic, 0);	/* enable ACK's */
214 }
215 
216 static void
217 sta_leave(void *arg, struct ieee80211_node *ni)
218 {
219 	struct ieee80211vap *vap = ni->ni_vap;
220 
221 	if (ni != vap->iv_bss)
222 		ieee80211_node_leave(ni);
223 }
224 
225 /*
226  * TDMA state machine handler.
227  */
228 static int
229 tdma_newstate(struct ieee80211vap *vap, enum ieee80211_state nstate, int arg)
230 {
231 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
232 	struct ieee80211com *ic = vap->iv_ic;
233 	enum ieee80211_state ostate;
234 	int status;
235 
236 	IEEE80211_LOCK_ASSERT(ic);
237 
238 	ostate = vap->iv_state;
239 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_STATE, "%s: %s -> %s (%d)\n",
240 	    __func__, ieee80211_state_name[ostate],
241 	    ieee80211_state_name[nstate], arg);
242 
243 	if (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS)
244 		callout_stop(&vap->iv_swbmiss);
245 	if (nstate == IEEE80211_S_SCAN &&
246 	    (ostate == IEEE80211_S_INIT || ostate == IEEE80211_S_RUN) &&
247 	    ts->tdma_slot != 0) {
248 		/*
249 		 * Override adhoc behaviour when operating as a slave;
250 		 * we need to scan even if the channel is locked.
251 		 */
252 		vap->iv_state = nstate;			/* state transition */
253 		ieee80211_cancel_scan(vap);		/* background scan */
254 		if (ostate == IEEE80211_S_RUN) {
255 			/* purge station table; entries are stale */
256 			ieee80211_iterate_nodes_vap(&ic->ic_sta, vap,
257 			    sta_leave, NULL);
258 		}
259 		if (vap->iv_flags_ext & IEEE80211_FEXT_SCANREQ) {
260 			ieee80211_check_scan(vap,
261 			    vap->iv_scanreq_flags,
262 			    vap->iv_scanreq_duration,
263 			    vap->iv_scanreq_mindwell,
264 			    vap->iv_scanreq_maxdwell,
265 			    vap->iv_scanreq_nssid, vap->iv_scanreq_ssid);
266 			vap->iv_flags_ext &= ~IEEE80211_FEXT_SCANREQ;
267 		} else
268 			ieee80211_check_scan_current(vap);
269 		status = 0;
270 	} else {
271 		status = ts->tdma_newstate(vap, nstate, arg);
272 	}
273 	if (status == 0 &&
274 	    nstate == IEEE80211_S_RUN && ostate != IEEE80211_S_RUN &&
275 	    (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS) &&
276 	    ts->tdma_slot != 0 &&
277 	    vap->iv_des_chan == IEEE80211_CHAN_ANYC) {
278 		/*
279 		 * Start s/w beacon miss timer for slave devices w/o
280 		 * hardware support.  Note we do this only if we're
281 		 * not locked to a channel (i.e. roam to follow the
282 		 * master). The 2x is a fudge for our doing this in
283 		 * software.
284 		 */
285 		vap->iv_swbmiss_period = IEEE80211_TU_TO_TICKS(
286 		    2 * vap->iv_bmissthreshold * ts->tdma_bintval *
287 		    ((ts->tdma_slotcnt * ts->tdma_slotlen) / 1024));
288 		vap->iv_swbmiss_count = 0;
289 		callout_reset(&vap->iv_swbmiss, vap->iv_swbmiss_period,
290 			ieee80211_swbmiss, vap);
291 	}
292 	return status;
293 }
294 
295 static void
296 tdma_beacon_miss(struct ieee80211vap *vap)
297 {
298 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
299 
300 	IEEE80211_LOCK_ASSERT(vap->iv_ic);
301 
302 	KASSERT((vap->iv_ic->ic_flags & IEEE80211_F_SCAN) == 0, ("scanning"));
303 	KASSERT(vap->iv_state == IEEE80211_S_RUN,
304 	    ("wrong state %d", vap->iv_state));
305 
306 	IEEE80211_DPRINTF(vap,
307 		IEEE80211_MSG_STATE | IEEE80211_MSG_TDMA | IEEE80211_MSG_DEBUG,
308 		"beacon miss, mode %u state %s\n",
309 		vap->iv_opmode, ieee80211_state_name[vap->iv_state]);
310 
311 	callout_stop(&vap->iv_swbmiss);
312 
313 	if (ts->tdma_peer != NULL) {	/* XXX? can this be null? */
314 		ieee80211_notify_node_leave(vap->iv_bss);
315 		ts->tdma_peer = NULL;
316 		/*
317 		 * Treat beacon miss like an associate failure wrt the
318 		 * scan policy; this forces the entry in the scan cache
319 		 * to be ignored after several tries.
320 		 */
321 		ieee80211_scan_assoc_fail(vap, vap->iv_bss->ni_macaddr,
322 		    IEEE80211_STATUS_TIMEOUT);
323 	}
324 #if 0
325 	ts->tdma_inuse = 0;		/* clear slot usage */
326 #endif
327 	ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
328 }
329 
330 static void
331 tdma_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m0,
332 	int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf)
333 {
334 	struct ieee80211com *ic = ni->ni_ic;
335 	struct ieee80211vap *vap = ni->ni_vap;
336 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
337 
338 	if (subtype == IEEE80211_FC0_SUBTYPE_BEACON &&
339 	    (ic->ic_flags & IEEE80211_F_SCAN) == 0) {
340 		struct ieee80211_frame *wh = mtod(m0, struct ieee80211_frame *);
341 		struct ieee80211_scanparams scan;
342 
343 		/* XXX TODO: use rxstatus to determine off-channel beacons */
344 		if (ieee80211_parse_beacon(ni, m0, ic->ic_curchan, &scan) != 0)
345 			return;
346 		if (scan.tdma == NULL) {
347 			/*
348 			 * TDMA stations must beacon a TDMA ie; ignore
349 			 * any other station.
350 			 * XXX detect overlapping bss and change channel
351 			 */
352 			IEEE80211_DISCARD(vap,
353 			    IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
354 			    wh, ieee80211_mgt_subtype_name(subtype),
355 			    "%s", "no TDMA ie");
356 			vap->iv_stats.is_rx_mgtdiscard++;
357 			return;
358 		}
359 		if (ni == vap->iv_bss &&
360 		    !IEEE80211_ADDR_EQ(wh->i_addr2, ni->ni_macaddr)) {
361 			/*
362 			 * Fake up a node for this newly
363 			 * discovered member of the IBSS.
364 			 */
365 			ni = ieee80211_add_neighbor(vap, wh, &scan);
366 			if (ni == NULL) {
367 				/* NB: stat kept for alloc failure */
368 				return;
369 			}
370 		}
371 		/*
372 		 * Check for state updates.
373 		 */
374 		if (IEEE80211_ADDR_EQ(wh->i_addr3, ni->ni_bssid)) {
375 			/*
376 			 * Count frame now that we know it's to be processed.
377 			 */
378 			vap->iv_stats.is_rx_beacon++;
379 			IEEE80211_NODE_STAT(ni, rx_beacons);
380 			/*
381 			 * Record tsf of last beacon.  NB: this must be
382 			 * done before calling tdma_process_params
383 			 * as deeper routines reference it.
384 			 */
385 			memcpy(&ni->ni_tstamp.data, scan.tstamp,
386 				sizeof(ni->ni_tstamp.data));
387 			/*
388 			 * Count beacon frame for s/w bmiss handling.
389 			 */
390 			vap->iv_swbmiss_count++;
391 			/*
392 			 * Process tdma ie.  The contents are used to sync
393 			 * the slot timing, reconfigure the bss, etc.
394 			 */
395 			(void) tdma_process_params(ni, scan.tdma, rssi, nf, wh);
396 			return;
397 		}
398 		/*
399 		 * NB: defer remaining work to the adhoc code; this causes
400 		 *     2x parsing of the frame but should happen infrequently
401 		 */
402 	}
403 	ts->tdma_recv_mgmt(ni, m0, subtype, rxs, rssi, nf);
404 }
405 
406 /*
407  * Update TDMA state on receipt of a beacon frame with
408  * a TDMA information element.  The sender's identity
409  * is provided so we can track who our peer is.  If pickslot
410  * is non-zero we scan the slot allocation state in the ie
411  * to locate a free slot for our use.
412  */
413 static int
414 tdma_update(struct ieee80211vap *vap, const struct ieee80211_tdma_param *tdma,
415 	struct ieee80211_node *ni, int pickslot)
416 {
417 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
418 	int slot, slotlen, update;
419 
420 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
421 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
422 
423 	update = 0;
424 	if (tdma->tdma_slotcnt != ts->tdma_slotcnt) {
425 		if (!TDMA_SLOTCNT_VALID(tdma->tdma_slotcnt)) {
426 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
427 				printf("%s: bad slot cnt %u\n",
428 				    __func__, tdma->tdma_slotcnt);
429 			return 0;
430 		}
431 		update |= TDMA_UPDATE_SLOTCNT;
432  	}
433 	slotlen = le16toh(tdma->tdma_slotlen) * 100;
434 	if (slotlen != ts->tdma_slotlen) {
435 		if (!TDMA_SLOTLEN_VALID(slotlen)) {
436 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
437 				printf("%s: bad slot len %u\n",
438 				    __func__, slotlen);
439 			return 0;
440 		}
441 		update |= TDMA_UPDATE_SLOTLEN;
442  	}
443 	if (tdma->tdma_bintval != ts->tdma_bintval) {
444 		if (!TDMA_BINTVAL_VALID(tdma->tdma_bintval)) {
445 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
446 				printf("%s: bad beacon interval %u\n",
447 				    __func__, tdma->tdma_bintval);
448 			return 0;
449 		}
450 		update |= TDMA_UPDATE_BINTVAL;
451  	}
452 	slot = ts->tdma_slot;
453 	if (pickslot) {
454 		/*
455 		 * Pick unoccupied slot.  Note we never choose slot 0.
456 		 */
457 		for (slot = tdma->tdma_slotcnt-1; slot > 0; slot--)
458 			if (isclr(tdma->tdma_inuse, slot))
459 				break;
460 		if (slot <= 0) {
461 			printf("%s: no free slot, slotcnt %u inuse: 0x%x\n",
462 				__func__, tdma->tdma_slotcnt,
463 				tdma->tdma_inuse[0]);
464 			/* XXX need to do something better */
465 			return 0;
466 		}
467 		if (slot != ts->tdma_slot)
468 			update |= TDMA_UPDATE_SLOT;
469 	}
470 	if (ni != ts->tdma_peer) {
471 		/* update everything */
472 		update = TDMA_UPDATE_SLOT
473 		       | TDMA_UPDATE_SLOTCNT
474 		       | TDMA_UPDATE_SLOTLEN
475 		       | TDMA_UPDATE_BINTVAL;
476 	}
477 
478 	if (update) {
479 		/*
480 		 * New/changed parameters; update runtime state.
481 		 */
482 		/* XXX overwrites user parameters */
483 		if (update & TDMA_UPDATE_SLOTCNT)
484 			ts->tdma_slotcnt = tdma->tdma_slotcnt;
485 		if (update & TDMA_UPDATE_SLOTLEN)
486 			ts->tdma_slotlen = slotlen;
487 		if (update & TDMA_UPDATE_SLOT)
488 			ts->tdma_slot = slot;
489 		if (update & TDMA_UPDATE_BINTVAL)
490 			ts->tdma_bintval = tdma->tdma_bintval;
491 		/* mark beacon to be updated before next xmit */
492 		ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
493 
494 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
495 		    "%s: slot %u slotcnt %u slotlen %u us bintval %u\n",
496 		    __func__, ts->tdma_slot, ts->tdma_slotcnt,
497 		    ts->tdma_slotlen, ts->tdma_bintval);
498 	}
499 	/*
500 	 * Notify driver.  Note we can be called before
501 	 * entering RUN state if we scanned and are
502 	 * joining an existing bss.  In that case do not
503 	 * call the driver because not all necessary state
504 	 * has been setup.  The next beacon will dtrt.
505 	 */
506 	if (vap->iv_state == IEEE80211_S_RUN)
507 		vap->iv_ic->ic_tdma_update(ni, tdma, update);
508 	/*
509 	 * Dispatch join event on first beacon from new master.
510 	 */
511 	if (ts->tdma_peer != ni) {
512 		if (ts->tdma_peer != NULL)
513 			ieee80211_notify_node_leave(vap->iv_bss);
514 		ieee80211_notify_node_join(ni, 1);
515 		/* NB: no reference, we just use the address */
516 		ts->tdma_peer = ni;
517 	}
518 	return 1;
519 }
520 
521 /*
522  * Process received TDMA parameters.
523  */
524 static int
525 tdma_process_params(struct ieee80211_node *ni, const u_int8_t *ie,
526 	int rssi, int nf, const struct ieee80211_frame *wh)
527 {
528 	struct ieee80211vap *vap = ni->ni_vap;
529 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
530 	const struct ieee80211_tdma_param *tdma =
531 		(const struct ieee80211_tdma_param *) ie;
532 	u_int len = ie[1];
533 
534 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
535 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
536 
537 	if (len < sizeof(*tdma) - 2) {
538 		IEEE80211_DISCARD_IE(vap,
539 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
540 		    wh, "tdma", "too short, len %u", len);
541 		return IEEE80211_REASON_IE_INVALID;
542 	}
543 	if (tdma->tdma_version != ts->tdma_version) {
544 		IEEE80211_DISCARD_IE(vap,
545 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
546 		    wh, "tdma", "bad version %u (ours %u)",
547 		    tdma->tdma_version, ts->tdma_version);
548 		return IEEE80211_REASON_IE_INVALID;
549 	}
550  	/*
551 	 * NB: ideally we'd check against tdma_slotcnt, but that
552 	 * would require extra effort so do this easy check that
553 	 * covers the work below; more stringent checks are done
554 	 * before we make more extensive use of the ie contents.
555 	 */
556 	if (tdma->tdma_slot >= TDMA_MAXSLOTS) {
557 		IEEE80211_DISCARD_IE(vap,
558 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
559 		    wh, "tdma", "invalid slot %u", tdma->tdma_slot);
560 		return IEEE80211_REASON_IE_INVALID;
561 	}
562 	/*
563 	 * Can reach here while scanning, update
564 	 * operational state only in RUN state.
565 	 */
566 	if (vap->iv_state == IEEE80211_S_RUN) {
567 		if (tdma->tdma_slot != ts->tdma_slot &&
568 		    isclr(ts->tdma_inuse, tdma->tdma_slot)) {
569 			IEEE80211_NOTE(vap, IEEE80211_MSG_TDMA, ni,
570 			    "discovered in slot %u", tdma->tdma_slot);
571 			setbit(ts->tdma_inuse, tdma->tdma_slot);
572 			/* XXX dispatch event only when operating as master */
573 			if (ts->tdma_slot == 0)
574 				ieee80211_notify_node_join(ni, 1);
575 		}
576 		setbit(ts->tdma_active, tdma->tdma_slot);
577 		if (tdma->tdma_slot == ts->tdma_slot-1) {
578 			/*
579 			 * Slave tsf synchronization to station
580 			 * just before us in the schedule. The driver
581 			 * is responsible for copying the timestamp
582 			 * of the received beacon into our beacon
583 			 * frame so the sender can calculate round
584 			 * trip time.  We cannot do that here because
585 			 * we don't know how to update our beacon frame.
586 			 */
587 			(void) tdma_update(vap, tdma, ni, 0);
588 			/* XXX reschedule swbmiss timer on parameter change */
589 		} else if (tdma->tdma_slot == ts->tdma_slot+1) {
590 			uint64_t tstamp;
591 #if 0
592 			uint32_t rstamp = (uint32_t) le64toh(rs->tsf);
593 			int32_t rtt;
594 #endif
595 			/*
596 			 * Use returned timstamp to calculate the
597 			 * roundtrip time.
598 			 */
599 			memcpy(&tstamp, tdma->tdma_tstamp, 8);
600 #if 0
601 			/* XXX use only 15 bits of rstamp */
602 			rtt = rstamp - (le64toh(tstamp) & 0x7fff);
603 			if (rtt < 0)
604 				rtt += 0x7fff;
605 			/* XXX hack to quiet normal use */
606 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_DOT1X,
607 			    "tdma rtt %5u [rstamp %5u tstamp %llu]\n",
608 			    rtt, rstamp,
609 			    (unsigned long long) le64toh(tstamp));
610 #endif
611 		} else if (tdma->tdma_slot == ts->tdma_slot &&
612 		    le64toh(ni->ni_tstamp.tsf) > vap->iv_bss->ni_tstamp.tsf) {
613 			/*
614 			 * Station using the same slot as us and has
615 			 * been around longer than us; we must move.
616 			 * Note this can happen if stations do not
617 			 * see each other while scanning.
618 			 */
619 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
620 			    "slot %u collision rxtsf %llu tsf %llu\n",
621 			    tdma->tdma_slot,
622 			    (unsigned long long) le64toh(ni->ni_tstamp.tsf),
623 			    vap->iv_bss->ni_tstamp.tsf);
624 			setbit(ts->tdma_inuse, tdma->tdma_slot);
625 
626 			(void) tdma_update(vap, tdma, ni, 1);
627 		}
628 	}
629 	return 0;
630 }
631 
632 int
633 ieee80211_tdma_getslot(struct ieee80211vap *vap)
634 {
635 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
636 
637 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
638 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
639 	return ts->tdma_slot;
640 }
641 
642 /*
643  * Parse a TDMA ie on station join and use it to setup node state.
644  */
645 void
646 ieee80211_parse_tdma(struct ieee80211_node *ni, const uint8_t *ie)
647 {
648 	struct ieee80211vap *vap = ni->ni_vap;
649 
650 	if (vap->iv_caps & IEEE80211_C_TDMA) {
651 		const struct ieee80211_tdma_param *tdma =
652 		    (const struct ieee80211_tdma_param *)ie;
653 		struct ieee80211_tdma_state *ts = vap->iv_tdma;
654 		/*
655 		 * Adopt TDMA configuration when joining an
656 		 * existing network.
657 		 */
658 		setbit(ts->tdma_inuse, tdma->tdma_slot);
659 		(void) tdma_update(vap, tdma, ni, 1);
660 		/*
661 		 * Propagate capabilities based on the local
662 		 * configuration and the remote station's advertised
663 		 * capabilities. In particular this permits us to
664 		 * enable use of QoS to disable ACK's.
665 		 */
666 		if ((vap->iv_flags & IEEE80211_F_WME) &&
667 		    ni->ni_ies.wme_ie != NULL)
668 			ni->ni_flags |= IEEE80211_NODE_QOS;
669 	}
670 }
671 
672 #define	TDMA_OUI_BYTES		0x00, 0x03, 0x7f
673 /*
674  * Add a TDMA parameters element to a frame.
675  */
676 uint8_t *
677 ieee80211_add_tdma(uint8_t *frm, struct ieee80211vap *vap)
678 {
679 #define	ADDSHORT(frm, v) do {			\
680 	frm[0] = (v) & 0xff;			\
681 	frm[1] = (v) >> 8;			\
682 	frm += 2;				\
683 } while (0)
684 	static const struct ieee80211_tdma_param param = {
685 		.tdma_id	= IEEE80211_ELEMID_VENDOR,
686 		.tdma_len	= sizeof(struct ieee80211_tdma_param) - 2,
687 		.tdma_oui	= { TDMA_OUI_BYTES },
688 		.tdma_type	= TDMA_OUI_TYPE,
689 		.tdma_subtype	= TDMA_SUBTYPE_PARAM,
690 		.tdma_version	= TDMA_VERSION,
691 	};
692 	const struct ieee80211_tdma_state *ts = vap->iv_tdma;
693 	uint16_t slotlen;
694 
695 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
696 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
697 
698 	memcpy(frm, &param, sizeof(param));
699 	frm += __offsetof(struct ieee80211_tdma_param, tdma_slot);
700 	*frm++ = ts->tdma_slot;
701 	*frm++ = ts->tdma_slotcnt;
702 	/* NB: convert units to fit in 16-bits */
703 	slotlen = ts->tdma_slotlen / 100;	/* 100us units */
704 	ADDSHORT(frm, slotlen);
705 	*frm++ = ts->tdma_bintval;
706 	*frm++ = ts->tdma_inuse[0];
707 	frm += 10;				/* pad+timestamp */
708 	return frm;
709 #undef ADDSHORT
710 }
711 #undef TDMA_OUI_BYTES
712 
713 /*
714  * Update TDMA state at TBTT.
715  */
716 void
717 ieee80211_tdma_update_beacon(struct ieee80211vap *vap,
718 	struct ieee80211_beacon_offsets *bo)
719 {
720 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
721 
722 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
723 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
724 
725 	if (isset(bo->bo_flags,  IEEE80211_BEACON_TDMA)) {
726 		(void) ieee80211_add_tdma(bo->bo_tdma, vap);
727 		clrbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
728 	}
729 	if (ts->tdma_slot != 0)		/* only on master */
730 		return;
731 	if (ts->tdma_count <= 0) {
732 		/*
733 		 * Time to update the mask of active/inuse stations.
734 		 * We track stations that we've received a beacon
735 		 * frame from and update this mask periodically.
736 		 * This allows us to miss a few beacons before marking
737 		 * a slot free for re-use.
738 		 */
739 		ts->tdma_inuse[0] = ts->tdma_active[0];
740 		ts->tdma_active[0] = 0x01;
741 		/* update next time 'round */
742 		/* XXX use notify framework */
743 		setbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
744 		/* NB: use s/w beacon miss threshold; may be too high */
745 		ts->tdma_count = vap->iv_bmissthreshold-1;
746 	} else
747 		ts->tdma_count--;
748 }
749 
750 static int
751 tdma_ioctl_get80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
752 {
753 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
754 
755 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
756 		return ENOSYS;
757 
758 	switch (ireq->i_type) {
759 	case IEEE80211_IOC_TDMA_SLOT:
760 		ireq->i_val = ts->tdma_slot;
761 		break;
762 	case IEEE80211_IOC_TDMA_SLOTCNT:
763 		ireq->i_val = ts->tdma_slotcnt;
764 		break;
765 	case IEEE80211_IOC_TDMA_SLOTLEN:
766 		ireq->i_val = ts->tdma_slotlen;
767 		break;
768 	case IEEE80211_IOC_TDMA_BINTERVAL:
769 		ireq->i_val = ts->tdma_bintval;
770 		break;
771 	default:
772 		return ENOSYS;
773 	}
774 	return 0;
775 }
776 IEEE80211_IOCTL_GET(tdma, tdma_ioctl_get80211);
777 
778 static int
779 tdma_ioctl_set80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
780 {
781 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
782 
783 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
784 		return ENOSYS;
785 
786 	switch (ireq->i_type) {
787 	case IEEE80211_IOC_TDMA_SLOT:
788 		if (!(0 <= ireq->i_val && ireq->i_val <= ts->tdma_slotcnt))
789 			return EINVAL;
790 		if (ireq->i_val != ts->tdma_slot) {
791 			ts->tdma_slot = ireq->i_val;
792 			goto restart;
793 		}
794 		break;
795 	case IEEE80211_IOC_TDMA_SLOTCNT:
796 		if (!TDMA_SLOTCNT_VALID(ireq->i_val))
797 			return EINVAL;
798 		if (ireq->i_val != ts->tdma_slotcnt) {
799 			ts->tdma_slotcnt = ireq->i_val;
800 			goto restart;
801 		}
802 		break;
803 	case IEEE80211_IOC_TDMA_SLOTLEN:
804 		/*
805 		 * XXX
806 		 * 150 insures at least 1/8 TU
807 		 * 0xfffff is the max duration for bursting
808 		 * (implict by way of 16-bit data type for i_val)
809 		 */
810 		if (!TDMA_SLOTLEN_VALID(ireq->i_val))
811 			return EINVAL;
812 		if (ireq->i_val != ts->tdma_slotlen) {
813 			ts->tdma_slotlen = ireq->i_val;
814 			goto restart;
815 		}
816 		break;
817 	case IEEE80211_IOC_TDMA_BINTERVAL:
818 		if (!TDMA_BINTVAL_VALID(ireq->i_val))
819 			return EINVAL;
820 		if (ireq->i_val != ts->tdma_bintval) {
821 			ts->tdma_bintval = ireq->i_val;
822 			goto restart;
823 		}
824 		break;
825 	default:
826 		return ENOSYS;
827 	}
828 	return 0;
829 restart:
830 	ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
831 	return ERESTART;
832 }
833 IEEE80211_IOCTL_SET(tdma, tdma_ioctl_set80211);
834 
835 #endif	/* IEEE80211_SUPPORT_TDMA */
836