xref: /freebsd/sys/net80211/ieee80211_tdma.c (revision 8ef24a0d4b28fe230e20637f56869cc4148cd2ca)
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 #ifdef	IEEE80211_SUPPORT_TDMA
40 
41 #include <sys/param.h>
42 #include <sys/systm.h>
43 #include <sys/mbuf.h>
44 #include <sys/malloc.h>
45 #include <sys/kernel.h>
46 
47 #include <sys/socket.h>
48 #include <sys/sockio.h>
49 #include <sys/endian.h>
50 #include <sys/errno.h>
51 #include <sys/proc.h>
52 #include <sys/sysctl.h>
53 
54 #include <net/if.h>
55 #include <net/if_media.h>
56 #include <net/if_llc.h>
57 #include <net/ethernet.h>
58 
59 #include <net/bpf.h>
60 
61 #include <net80211/ieee80211_var.h>
62 #include <net80211/ieee80211_tdma.h>
63 #include <net80211/ieee80211_input.h>
64 
65 #ifndef TDMA_SLOTLEN_DEFAULT
66 #define	TDMA_SLOTLEN_DEFAULT	10*1000		/* 10ms */
67 #endif
68 #ifndef TDMA_SLOTCNT_DEFAULT
69 #define	TDMA_SLOTCNT_DEFAULT	2		/* 2x (pt-to-pt) */
70 #endif
71 #ifndef TDMA_BINTVAL_DEFAULT
72 #define	TDMA_BINTVAL_DEFAULT	5		/* 5x ~= 100TU beacon intvl */
73 #endif
74 #ifndef TDMA_TXRATE_11B_DEFAULT
75 #define	TDMA_TXRATE_11B_DEFAULT	2*11
76 #endif
77 #ifndef TDMA_TXRATE_11G_DEFAULT
78 #define	TDMA_TXRATE_11G_DEFAULT	2*24
79 #endif
80 #ifndef TDMA_TXRATE_11A_DEFAULT
81 #define	TDMA_TXRATE_11A_DEFAULT	2*24
82 #endif
83 #ifndef TDMA_TXRATE_TURBO_DEFAULT
84 #define	TDMA_TXRATE_TURBO_DEFAULT	2*24
85 #endif
86 #ifndef TDMA_TXRATE_HALF_DEFAULT
87 #define	TDMA_TXRATE_HALF_DEFAULT	2*12
88 #endif
89 #ifndef TDMA_TXRATE_QUARTER_DEFAULT
90 #define	TDMA_TXRATE_QUARTER_DEFAULT	2*6
91 #endif
92 #ifndef TDMA_TXRATE_11NA_DEFAULT
93 #define	TDMA_TXRATE_11NA_DEFAULT	(4 | IEEE80211_RATE_MCS)
94 #endif
95 #ifndef TDMA_TXRATE_11NG_DEFAULT
96 #define	TDMA_TXRATE_11NG_DEFAULT	(4 | IEEE80211_RATE_MCS)
97 #endif
98 
99 #define	TDMA_VERSION_VALID(_version) \
100 	(TDMA_VERSION_V2 <= (_version) && (_version) <= TDMA_VERSION)
101 #define	TDMA_SLOTCNT_VALID(_slotcnt) \
102 	(2 <= (_slotcnt) && (_slotcnt) <= TDMA_MAXSLOTS)
103 /* XXX magic constants */
104 #define	TDMA_SLOTLEN_VALID(_slotlen) \
105 	(2*100 <= (_slotlen) && (unsigned)(_slotlen) <= 0xfffff)
106 /* XXX probably should set a max */
107 #define	TDMA_BINTVAL_VALID(_bintval)	(1 <= (_bintval))
108 
109 /*
110  * This code is not prepared to handle more than 2 slots.
111  */
112 CTASSERT(TDMA_MAXSLOTS == 2);
113 
114 static void tdma_vdetach(struct ieee80211vap *vap);
115 static int tdma_newstate(struct ieee80211vap *, enum ieee80211_state, int);
116 static void tdma_beacon_miss(struct ieee80211vap *vap);
117 static void tdma_recv_mgmt(struct ieee80211_node *, struct mbuf *,
118 	int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf);
119 static int tdma_update(struct ieee80211vap *vap,
120 	const struct ieee80211_tdma_param *tdma, struct ieee80211_node *ni,
121 	int pickslot);
122 static int tdma_process_params(struct ieee80211_node *ni,
123 	const u_int8_t *ie, int rssi, int nf, const struct ieee80211_frame *wh);
124 
125 static void
126 settxparms(struct ieee80211vap *vap, enum ieee80211_phymode mode, int rate)
127 {
128 	vap->iv_txparms[mode].ucastrate = rate;
129 	vap->iv_txparms[mode].mcastrate = rate;
130 }
131 
132 static void
133 setackpolicy(struct ieee80211com *ic, int noack)
134 {
135 	struct ieee80211_wme_state *wme = &ic->ic_wme;
136 	int ac;
137 
138 	for (ac = 0; ac < WME_NUM_AC; ac++) {
139 		wme->wme_chanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
140 		wme->wme_wmeChanParams.cap_wmeParams[ac].wmep_noackPolicy = noack;
141 	}
142 }
143 
144 void
145 ieee80211_tdma_vattach(struct ieee80211vap *vap)
146 {
147 	struct ieee80211_tdma_state *ts;
148 
149 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
150 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
151 
152 	ts = (struct ieee80211_tdma_state *) IEEE80211_MALLOC(
153 	     sizeof(struct ieee80211_tdma_state), M_80211_VAP,
154 	     IEEE80211_M_NOWAIT | IEEE80211_M_ZERO);
155 	if (ts == NULL) {
156 		printf("%s: cannot allocate TDMA state block\n", __func__);
157 		/* NB: fall back to adhdemo mode */
158 		vap->iv_caps &= ~IEEE80211_C_TDMA;
159 		return;
160 	}
161 	/* NB: default configuration is passive so no beacons */
162 	ts->tdma_version = TDMA_VERSION;
163 	ts->tdma_slotlen = TDMA_SLOTLEN_DEFAULT;
164 	ts->tdma_slotcnt = TDMA_SLOTCNT_DEFAULT;
165 	ts->tdma_bintval = TDMA_BINTVAL_DEFAULT;
166 	ts->tdma_slot = 1;			/* passive operation */
167 
168 	/* setup default fixed rates */
169 	settxparms(vap, IEEE80211_MODE_11A, TDMA_TXRATE_11A_DEFAULT);
170 	settxparms(vap, IEEE80211_MODE_11B, TDMA_TXRATE_11B_DEFAULT);
171 	settxparms(vap, IEEE80211_MODE_11G, TDMA_TXRATE_11G_DEFAULT);
172 	settxparms(vap, IEEE80211_MODE_TURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
173 	settxparms(vap, IEEE80211_MODE_TURBO_G, TDMA_TXRATE_TURBO_DEFAULT);
174 	settxparms(vap, IEEE80211_MODE_STURBO_A, TDMA_TXRATE_TURBO_DEFAULT);
175 	settxparms(vap, IEEE80211_MODE_11NA, TDMA_TXRATE_11NA_DEFAULT);
176 	settxparms(vap, IEEE80211_MODE_11NG, TDMA_TXRATE_11NG_DEFAULT);
177 	settxparms(vap, IEEE80211_MODE_HALF, TDMA_TXRATE_HALF_DEFAULT);
178 	settxparms(vap, IEEE80211_MODE_QUARTER, TDMA_TXRATE_QUARTER_DEFAULT);
179 
180 	setackpolicy(vap->iv_ic, 1);	/* disable ACK's */
181 
182 	ts->tdma_opdetach = vap->iv_opdetach;
183 	vap->iv_opdetach = tdma_vdetach;
184 	ts->tdma_newstate = vap->iv_newstate;
185 	vap->iv_newstate = tdma_newstate;
186 	vap->iv_bmiss = tdma_beacon_miss;
187 	ts->tdma_recv_mgmt = vap->iv_recv_mgmt;
188 	vap->iv_recv_mgmt = tdma_recv_mgmt;
189 
190 	vap->iv_tdma = ts;
191 }
192 
193 static void
194 tdma_vdetach(struct ieee80211vap *vap)
195 {
196 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
197 
198 	if (ts == NULL) {
199 		/* NB: should not have touched any ic state */
200 		return;
201 	}
202 	ts->tdma_opdetach(vap);
203 	IEEE80211_FREE(vap->iv_tdma, M_80211_VAP);
204 	vap->iv_tdma = NULL;
205 
206 	setackpolicy(vap->iv_ic, 0);	/* enable ACK's */
207 }
208 
209 static void
210 sta_leave(void *arg, struct ieee80211_node *ni)
211 {
212 	struct ieee80211vap *vap = arg;
213 
214 	if (ni->ni_vap == vap && ni != vap->iv_bss)
215 		ieee80211_node_leave(ni);
216 }
217 
218 /*
219  * TDMA state machine handler.
220  */
221 static int
222 tdma_newstate(struct ieee80211vap *vap, enum ieee80211_state nstate, int arg)
223 {
224 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
225 	struct ieee80211com *ic = vap->iv_ic;
226 	enum ieee80211_state ostate;
227 	int status;
228 
229 	IEEE80211_LOCK_ASSERT(ic);
230 
231 	ostate = vap->iv_state;
232 	IEEE80211_DPRINTF(vap, IEEE80211_MSG_STATE, "%s: %s -> %s (%d)\n",
233 	    __func__, ieee80211_state_name[ostate],
234 	    ieee80211_state_name[nstate], arg);
235 
236 	if (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS)
237 		callout_stop(&vap->iv_swbmiss);
238 	if (nstate == IEEE80211_S_SCAN &&
239 	    (ostate == IEEE80211_S_INIT || ostate == IEEE80211_S_RUN) &&
240 	    ts->tdma_slot != 0) {
241 		/*
242 		 * Override adhoc behaviour when operating as a slave;
243 		 * we need to scan even if the channel is locked.
244 		 */
245 		vap->iv_state = nstate;			/* state transition */
246 		ieee80211_cancel_scan(vap);		/* background scan */
247 		if (ostate == IEEE80211_S_RUN) {
248 			/* purge station table; entries are stale */
249 			ieee80211_iterate_nodes(&ic->ic_sta, sta_leave, vap);
250 		}
251 		if (vap->iv_flags_ext & IEEE80211_FEXT_SCANREQ) {
252 			ieee80211_check_scan(vap,
253 			    vap->iv_scanreq_flags,
254 			    vap->iv_scanreq_duration,
255 			    vap->iv_scanreq_mindwell,
256 			    vap->iv_scanreq_maxdwell,
257 			    vap->iv_scanreq_nssid, vap->iv_scanreq_ssid);
258 			vap->iv_flags_ext &= ~IEEE80211_FEXT_SCANREQ;
259 		} else
260 			ieee80211_check_scan_current(vap);
261 		status = 0;
262 	} else {
263 		status = ts->tdma_newstate(vap, nstate, arg);
264 	}
265 	if (status == 0 &&
266 	    nstate == IEEE80211_S_RUN && ostate != IEEE80211_S_RUN &&
267 	    (vap->iv_flags_ext & IEEE80211_FEXT_SWBMISS) &&
268 	    ts->tdma_slot != 0 &&
269 	    vap->iv_des_chan == IEEE80211_CHAN_ANYC) {
270 		/*
271 		 * Start s/w beacon miss timer for slave devices w/o
272 		 * hardware support.  Note we do this only if we're
273 		 * not locked to a channel (i.e. roam to follow the
274 		 * master). The 2x is a fudge for our doing this in
275 		 * software.
276 		 */
277 		vap->iv_swbmiss_period = IEEE80211_TU_TO_TICKS(
278 		    2 * vap->iv_bmissthreshold * ts->tdma_bintval *
279 		    ((ts->tdma_slotcnt * ts->tdma_slotlen) / 1024));
280 		vap->iv_swbmiss_count = 0;
281 		callout_reset(&vap->iv_swbmiss, vap->iv_swbmiss_period,
282 			ieee80211_swbmiss, vap);
283 	}
284 	return status;
285 }
286 
287 static void
288 tdma_beacon_miss(struct ieee80211vap *vap)
289 {
290 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
291 
292 	IEEE80211_LOCK_ASSERT(vap->iv_ic);
293 
294 	KASSERT((vap->iv_ic->ic_flags & IEEE80211_F_SCAN) == 0, ("scanning"));
295 	KASSERT(vap->iv_state == IEEE80211_S_RUN,
296 	    ("wrong state %d", vap->iv_state));
297 
298 	IEEE80211_DPRINTF(vap,
299 		IEEE80211_MSG_STATE | IEEE80211_MSG_TDMA | IEEE80211_MSG_DEBUG,
300 		"beacon miss, mode %u state %s\n",
301 		vap->iv_opmode, ieee80211_state_name[vap->iv_state]);
302 
303 	callout_stop(&vap->iv_swbmiss);
304 
305 	if (ts->tdma_peer != NULL) {	/* XXX? can this be null? */
306 		ieee80211_notify_node_leave(vap->iv_bss);
307 		ts->tdma_peer = NULL;
308 		/*
309 		 * Treat beacon miss like an associate failure wrt the
310 		 * scan policy; this forces the entry in the scan cache
311 		 * to be ignored after several tries.
312 		 */
313 		ieee80211_scan_assoc_fail(vap, vap->iv_bss->ni_macaddr,
314 		    IEEE80211_STATUS_TIMEOUT);
315 	}
316 #if 0
317 	ts->tdma_inuse = 0;		/* clear slot usage */
318 #endif
319 	ieee80211_new_state(vap, IEEE80211_S_SCAN, 0);
320 }
321 
322 static void
323 tdma_recv_mgmt(struct ieee80211_node *ni, struct mbuf *m0,
324 	int subtype, const struct ieee80211_rx_stats *rxs, int rssi, int nf)
325 {
326 	struct ieee80211com *ic = ni->ni_ic;
327 	struct ieee80211vap *vap = ni->ni_vap;
328 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
329 
330 	if (subtype == IEEE80211_FC0_SUBTYPE_BEACON &&
331 	    (ic->ic_flags & IEEE80211_F_SCAN) == 0) {
332 		struct ieee80211_frame *wh = mtod(m0, struct ieee80211_frame *);
333 		struct ieee80211_scanparams scan;
334 
335 		/* XXX TODO: use rxstatus to determine off-channel beacons */
336 		if (ieee80211_parse_beacon(ni, m0, ic->ic_curchan, &scan) != 0)
337 			return;
338 		if (scan.tdma == NULL) {
339 			/*
340 			 * TDMA stations must beacon a TDMA ie; ignore
341 			 * any other station.
342 			 * XXX detect overlapping bss and change channel
343 			 */
344 			IEEE80211_DISCARD(vap,
345 			    IEEE80211_MSG_ELEMID | IEEE80211_MSG_INPUT,
346 			    wh, ieee80211_mgt_subtype_name(subtype),
347 			    "%s", "no TDMA ie");
348 			vap->iv_stats.is_rx_mgtdiscard++;
349 			return;
350 		}
351 		if (ni == vap->iv_bss &&
352 		    !IEEE80211_ADDR_EQ(wh->i_addr2, ni->ni_macaddr)) {
353 			/*
354 			 * Fake up a node for this newly
355 			 * discovered member of the IBSS.
356 			 */
357 			ni = ieee80211_add_neighbor(vap, wh, &scan);
358 			if (ni == NULL) {
359 				/* NB: stat kept for alloc failure */
360 				return;
361 			}
362 		}
363 		/*
364 		 * Check for state updates.
365 		 */
366 		if (IEEE80211_ADDR_EQ(wh->i_addr3, ni->ni_bssid)) {
367 			/*
368 			 * Count frame now that we know it's to be processed.
369 			 */
370 			vap->iv_stats.is_rx_beacon++;
371 			IEEE80211_NODE_STAT(ni, rx_beacons);
372 			/*
373 			 * Record tsf of last beacon.  NB: this must be
374 			 * done before calling tdma_process_params
375 			 * as deeper routines reference it.
376 			 */
377 			memcpy(&ni->ni_tstamp.data, scan.tstamp,
378 				sizeof(ni->ni_tstamp.data));
379 			/*
380 			 * Count beacon frame for s/w bmiss handling.
381 			 */
382 			vap->iv_swbmiss_count++;
383 			/*
384 			 * Process tdma ie.  The contents are used to sync
385 			 * the slot timing, reconfigure the bss, etc.
386 			 */
387 			(void) tdma_process_params(ni, scan.tdma, rssi, nf, wh);
388 			return;
389 		}
390 		/*
391 		 * NB: defer remaining work to the adhoc code; this causes
392 		 *     2x parsing of the frame but should happen infrequently
393 		 */
394 	}
395 	ts->tdma_recv_mgmt(ni, m0, subtype, rxs, rssi, nf);
396 }
397 
398 /*
399  * Update TDMA state on receipt of a beacon frame with
400  * a TDMA information element.  The sender's identity
401  * is provided so we can track who our peer is.  If pickslot
402  * is non-zero we scan the slot allocation state in the ie
403  * to locate a free slot for our use.
404  */
405 static int
406 tdma_update(struct ieee80211vap *vap, const struct ieee80211_tdma_param *tdma,
407 	struct ieee80211_node *ni, int pickslot)
408 {
409 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
410 	int slot, slotlen, update;
411 
412 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
413 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
414 
415 	update = 0;
416 	if (tdma->tdma_slotcnt != ts->tdma_slotcnt) {
417 		if (!TDMA_SLOTCNT_VALID(tdma->tdma_slotcnt)) {
418 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
419 				printf("%s: bad slot cnt %u\n",
420 				    __func__, tdma->tdma_slotcnt);
421 			return 0;
422 		}
423 		update |= TDMA_UPDATE_SLOTCNT;
424  	}
425 	slotlen = le16toh(tdma->tdma_slotlen) * 100;
426 	if (slotlen != ts->tdma_slotlen) {
427 		if (!TDMA_SLOTLEN_VALID(slotlen)) {
428 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
429 				printf("%s: bad slot len %u\n",
430 				    __func__, slotlen);
431 			return 0;
432 		}
433 		update |= TDMA_UPDATE_SLOTLEN;
434  	}
435 	if (tdma->tdma_bintval != ts->tdma_bintval) {
436 		if (!TDMA_BINTVAL_VALID(tdma->tdma_bintval)) {
437 			if (ppsratecheck(&ts->tdma_lastprint, &ts->tdma_fails, 1))
438 				printf("%s: bad beacon interval %u\n",
439 				    __func__, tdma->tdma_bintval);
440 			return 0;
441 		}
442 		update |= TDMA_UPDATE_BINTVAL;
443  	}
444 	slot = ts->tdma_slot;
445 	if (pickslot) {
446 		/*
447 		 * Pick unoccupied slot.  Note we never choose slot 0.
448 		 */
449 		for (slot = tdma->tdma_slotcnt-1; slot > 0; slot--)
450 			if (isclr(tdma->tdma_inuse, slot))
451 				break;
452 		if (slot <= 0) {
453 			printf("%s: no free slot, slotcnt %u inuse: 0x%x\n",
454 				__func__, tdma->tdma_slotcnt,
455 				tdma->tdma_inuse[0]);
456 			/* XXX need to do something better */
457 			return 0;
458 		}
459 		if (slot != ts->tdma_slot)
460 			update |= TDMA_UPDATE_SLOT;
461 	}
462 	if (ni != ts->tdma_peer) {
463 		/* update everything */
464 		update = TDMA_UPDATE_SLOT
465 		       | TDMA_UPDATE_SLOTCNT
466 		       | TDMA_UPDATE_SLOTLEN
467 		       | TDMA_UPDATE_BINTVAL;
468 	}
469 
470 	if (update) {
471 		/*
472 		 * New/changed parameters; update runtime state.
473 		 */
474 		/* XXX overwrites user parameters */
475 		if (update & TDMA_UPDATE_SLOTCNT)
476 			ts->tdma_slotcnt = tdma->tdma_slotcnt;
477 		if (update & TDMA_UPDATE_SLOTLEN)
478 			ts->tdma_slotlen = slotlen;
479 		if (update & TDMA_UPDATE_SLOT)
480 			ts->tdma_slot = slot;
481 		if (update & TDMA_UPDATE_BINTVAL)
482 			ts->tdma_bintval = tdma->tdma_bintval;
483 		/* mark beacon to be updated before next xmit */
484 		ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
485 
486 		IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
487 		    "%s: slot %u slotcnt %u slotlen %u us bintval %u\n",
488 		    __func__, ts->tdma_slot, ts->tdma_slotcnt,
489 		    ts->tdma_slotlen, ts->tdma_bintval);
490 	}
491 	/*
492 	 * Notify driver.  Note we can be called before
493 	 * entering RUN state if we scanned and are
494 	 * joining an existing bss.  In that case do not
495 	 * call the driver because not all necessary state
496 	 * has been setup.  The next beacon will dtrt.
497 	 */
498 	if (vap->iv_state == IEEE80211_S_RUN)
499 		vap->iv_ic->ic_tdma_update(ni, tdma, update);
500 	/*
501 	 * Dispatch join event on first beacon from new master.
502 	 */
503 	if (ts->tdma_peer != ni) {
504 		if (ts->tdma_peer != NULL)
505 			ieee80211_notify_node_leave(vap->iv_bss);
506 		ieee80211_notify_node_join(ni, 1);
507 		/* NB: no reference, we just use the address */
508 		ts->tdma_peer = ni;
509 	}
510 	return 1;
511 }
512 
513 /*
514  * Process received TDMA parameters.
515  */
516 static int
517 tdma_process_params(struct ieee80211_node *ni, const u_int8_t *ie,
518 	int rssi, int nf, const struct ieee80211_frame *wh)
519 {
520 	struct ieee80211vap *vap = ni->ni_vap;
521 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
522 	const struct ieee80211_tdma_param *tdma =
523 		(const struct ieee80211_tdma_param *) ie;
524 	u_int len = ie[1];
525 
526 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
527 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
528 
529 	if (len < sizeof(*tdma) - 2) {
530 		IEEE80211_DISCARD_IE(vap,
531 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
532 		    wh, "tdma", "too short, len %u", len);
533 		return IEEE80211_REASON_IE_INVALID;
534 	}
535 	if (tdma->tdma_version != ts->tdma_version) {
536 		IEEE80211_DISCARD_IE(vap,
537 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
538 		    wh, "tdma", "bad version %u (ours %u)",
539 		    tdma->tdma_version, ts->tdma_version);
540 		return IEEE80211_REASON_IE_INVALID;
541 	}
542  	/*
543 	 * NB: ideally we'd check against tdma_slotcnt, but that
544 	 * would require extra effort so do this easy check that
545 	 * covers the work below; more stringent checks are done
546 	 * before we make more extensive use of the ie contents.
547 	 */
548 	if (tdma->tdma_slot >= TDMA_MAXSLOTS) {
549 		IEEE80211_DISCARD_IE(vap,
550 		    IEEE80211_MSG_ELEMID | IEEE80211_MSG_TDMA,
551 		    wh, "tdma", "invalid slot %u", tdma->tdma_slot);
552 		return IEEE80211_REASON_IE_INVALID;
553 	}
554 	/*
555 	 * Can reach here while scanning, update
556 	 * operational state only in RUN state.
557 	 */
558 	if (vap->iv_state == IEEE80211_S_RUN) {
559 		if (tdma->tdma_slot != ts->tdma_slot &&
560 		    isclr(ts->tdma_inuse, tdma->tdma_slot)) {
561 			IEEE80211_NOTE(vap, IEEE80211_MSG_TDMA, ni,
562 			    "discovered in slot %u", tdma->tdma_slot);
563 			setbit(ts->tdma_inuse, tdma->tdma_slot);
564 			/* XXX dispatch event only when operating as master */
565 			if (ts->tdma_slot == 0)
566 				ieee80211_notify_node_join(ni, 1);
567 		}
568 		setbit(ts->tdma_active, tdma->tdma_slot);
569 		if (tdma->tdma_slot == ts->tdma_slot-1) {
570 			/*
571 			 * Slave tsf synchronization to station
572 			 * just before us in the schedule. The driver
573 			 * is responsible for copying the timestamp
574 			 * of the received beacon into our beacon
575 			 * frame so the sender can calculate round
576 			 * trip time.  We cannot do that here because
577 			 * we don't know how to update our beacon frame.
578 			 */
579 			(void) tdma_update(vap, tdma, ni, 0);
580 			/* XXX reschedule swbmiss timer on parameter change */
581 		} else if (tdma->tdma_slot == ts->tdma_slot+1) {
582 			uint64_t tstamp;
583 #if 0
584 			uint32_t rstamp = (uint32_t) le64toh(rs->tsf);
585 			int32_t rtt;
586 #endif
587 			/*
588 			 * Use returned timstamp to calculate the
589 			 * roundtrip time.
590 			 */
591 			memcpy(&tstamp, tdma->tdma_tstamp, 8);
592 #if 0
593 			/* XXX use only 15 bits of rstamp */
594 			rtt = rstamp - (le64toh(tstamp) & 0x7fff);
595 			if (rtt < 0)
596 				rtt += 0x7fff;
597 			/* XXX hack to quiet normal use */
598 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_DOT1X,
599 			    "tdma rtt %5u [rstamp %5u tstamp %llu]\n",
600 			    rtt, rstamp,
601 			    (unsigned long long) le64toh(tstamp));
602 #endif
603 		} else if (tdma->tdma_slot == ts->tdma_slot &&
604 		    le64toh(ni->ni_tstamp.tsf) > vap->iv_bss->ni_tstamp.tsf) {
605 			/*
606 			 * Station using the same slot as us and has
607 			 * been around longer than us; we must move.
608 			 * Note this can happen if stations do not
609 			 * see each other while scanning.
610 			 */
611 			IEEE80211_DPRINTF(vap, IEEE80211_MSG_TDMA,
612 			    "slot %u collision rxtsf %llu tsf %llu\n",
613 			    tdma->tdma_slot,
614 			    (unsigned long long) le64toh(ni->ni_tstamp.tsf),
615 			    vap->iv_bss->ni_tstamp.tsf);
616 			setbit(ts->tdma_inuse, tdma->tdma_slot);
617 
618 			(void) tdma_update(vap, tdma, ni, 1);
619 		}
620 	}
621 	return 0;
622 }
623 
624 int
625 ieee80211_tdma_getslot(struct ieee80211vap *vap)
626 {
627 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
628 
629 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
630 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
631 	return ts->tdma_slot;
632 }
633 
634 /*
635  * Parse a TDMA ie on station join and use it to setup node state.
636  */
637 void
638 ieee80211_parse_tdma(struct ieee80211_node *ni, const uint8_t *ie)
639 {
640 	struct ieee80211vap *vap = ni->ni_vap;
641 
642 	if (vap->iv_caps & IEEE80211_C_TDMA) {
643 		const struct ieee80211_tdma_param *tdma =
644 		    (const struct ieee80211_tdma_param *)ie;
645 		struct ieee80211_tdma_state *ts = vap->iv_tdma;
646 		/*
647 		 * Adopt TDMA configuration when joining an
648 		 * existing network.
649 		 */
650 		setbit(ts->tdma_inuse, tdma->tdma_slot);
651 		(void) tdma_update(vap, tdma, ni, 1);
652 		/*
653 		 * Propagate capabilities based on the local
654 		 * configuration and the remote station's advertised
655 		 * capabilities. In particular this permits us to
656 		 * enable use of QoS to disable ACK's.
657 		 */
658 		if ((vap->iv_flags & IEEE80211_F_WME) &&
659 		    ni->ni_ies.wme_ie != NULL)
660 			ni->ni_flags |= IEEE80211_NODE_QOS;
661 	}
662 }
663 
664 #define	TDMA_OUI_BYTES		0x00, 0x03, 0x7f
665 /*
666  * Add a TDMA parameters element to a frame.
667  */
668 uint8_t *
669 ieee80211_add_tdma(uint8_t *frm, struct ieee80211vap *vap)
670 {
671 #define	ADDSHORT(frm, v) do {			\
672 	frm[0] = (v) & 0xff;			\
673 	frm[1] = (v) >> 8;			\
674 	frm += 2;				\
675 } while (0)
676 	static const struct ieee80211_tdma_param param = {
677 		.tdma_id	= IEEE80211_ELEMID_VENDOR,
678 		.tdma_len	= sizeof(struct ieee80211_tdma_param) - 2,
679 		.tdma_oui	= { TDMA_OUI_BYTES },
680 		.tdma_type	= TDMA_OUI_TYPE,
681 		.tdma_subtype	= TDMA_SUBTYPE_PARAM,
682 		.tdma_version	= TDMA_VERSION,
683 	};
684 	const struct ieee80211_tdma_state *ts = vap->iv_tdma;
685 	uint16_t slotlen;
686 
687 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
688 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
689 
690 	memcpy(frm, &param, sizeof(param));
691 	frm += __offsetof(struct ieee80211_tdma_param, tdma_slot);
692 	*frm++ = ts->tdma_slot;
693 	*frm++ = ts->tdma_slotcnt;
694 	/* NB: convert units to fit in 16-bits */
695 	slotlen = ts->tdma_slotlen / 100;	/* 100us units */
696 	ADDSHORT(frm, slotlen);
697 	*frm++ = ts->tdma_bintval;
698 	*frm++ = ts->tdma_inuse[0];
699 	frm += 10;				/* pad+timestamp */
700 	return frm;
701 #undef ADDSHORT
702 }
703 #undef TDMA_OUI_BYTES
704 
705 /*
706  * Update TDMA state at TBTT.
707  */
708 void
709 ieee80211_tdma_update_beacon(struct ieee80211vap *vap,
710 	struct ieee80211_beacon_offsets *bo)
711 {
712 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
713 
714 	KASSERT(vap->iv_caps & IEEE80211_C_TDMA,
715 	     ("not a tdma vap, caps 0x%x", vap->iv_caps));
716 
717 	if (isset(bo->bo_flags,  IEEE80211_BEACON_TDMA)) {
718 		(void) ieee80211_add_tdma(bo->bo_tdma, vap);
719 		clrbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
720 	}
721 	if (ts->tdma_slot != 0)		/* only on master */
722 		return;
723 	if (ts->tdma_count <= 0) {
724 		/*
725 		 * Time to update the mask of active/inuse stations.
726 		 * We track stations that we've received a beacon
727 		 * frame from and update this mask periodically.
728 		 * This allows us to miss a few beacons before marking
729 		 * a slot free for re-use.
730 		 */
731 		ts->tdma_inuse[0] = ts->tdma_active[0];
732 		ts->tdma_active[0] = 0x01;
733 		/* update next time 'round */
734 		/* XXX use notify framework */
735 		setbit(bo->bo_flags, IEEE80211_BEACON_TDMA);
736 		/* NB: use s/w beacon miss threshold; may be too high */
737 		ts->tdma_count = vap->iv_bmissthreshold-1;
738 	} else
739 		ts->tdma_count--;
740 }
741 
742 static int
743 tdma_ioctl_get80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
744 {
745 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
746 
747 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
748 		return ENOSYS;
749 
750 	switch (ireq->i_type) {
751 	case IEEE80211_IOC_TDMA_SLOT:
752 		ireq->i_val = ts->tdma_slot;
753 		break;
754 	case IEEE80211_IOC_TDMA_SLOTCNT:
755 		ireq->i_val = ts->tdma_slotcnt;
756 		break;
757 	case IEEE80211_IOC_TDMA_SLOTLEN:
758 		ireq->i_val = ts->tdma_slotlen;
759 		break;
760 	case IEEE80211_IOC_TDMA_BINTERVAL:
761 		ireq->i_val = ts->tdma_bintval;
762 		break;
763 	default:
764 		return ENOSYS;
765 	}
766 	return 0;
767 }
768 IEEE80211_IOCTL_GET(tdma, tdma_ioctl_get80211);
769 
770 static int
771 tdma_ioctl_set80211(struct ieee80211vap *vap, struct ieee80211req *ireq)
772 {
773 	struct ieee80211_tdma_state *ts = vap->iv_tdma;
774 
775 	if ((vap->iv_caps & IEEE80211_C_TDMA) == 0)
776 		return ENOSYS;
777 
778 	switch (ireq->i_type) {
779 	case IEEE80211_IOC_TDMA_SLOT:
780 		if (!(0 <= ireq->i_val && ireq->i_val <= ts->tdma_slotcnt))
781 			return EINVAL;
782 		if (ireq->i_val != ts->tdma_slot) {
783 			ts->tdma_slot = ireq->i_val;
784 			goto restart;
785 		}
786 		break;
787 	case IEEE80211_IOC_TDMA_SLOTCNT:
788 		if (!TDMA_SLOTCNT_VALID(ireq->i_val))
789 			return EINVAL;
790 		if (ireq->i_val != ts->tdma_slotcnt) {
791 			ts->tdma_slotcnt = ireq->i_val;
792 			goto restart;
793 		}
794 		break;
795 	case IEEE80211_IOC_TDMA_SLOTLEN:
796 		/*
797 		 * XXX
798 		 * 150 insures at least 1/8 TU
799 		 * 0xfffff is the max duration for bursting
800 		 * (implict by way of 16-bit data type for i_val)
801 		 */
802 		if (!TDMA_SLOTLEN_VALID(ireq->i_val))
803 			return EINVAL;
804 		if (ireq->i_val != ts->tdma_slotlen) {
805 			ts->tdma_slotlen = ireq->i_val;
806 			goto restart;
807 		}
808 		break;
809 	case IEEE80211_IOC_TDMA_BINTERVAL:
810 		if (!TDMA_BINTVAL_VALID(ireq->i_val))
811 			return EINVAL;
812 		if (ireq->i_val != ts->tdma_bintval) {
813 			ts->tdma_bintval = ireq->i_val;
814 			goto restart;
815 		}
816 		break;
817 	default:
818 		return ENOSYS;
819 	}
820 	return 0;
821 restart:
822 	ieee80211_beacon_notify(vap, IEEE80211_BEACON_TDMA);
823 	return ERESTART;
824 }
825 IEEE80211_IOCTL_SET(tdma, tdma_ioctl_set80211);
826 
827 #endif	/* IEEE80211_SUPPORT_TDMA */
828