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/net/irda/irlap.c

http://github.com/mirrors/linux
C | 1207 lines | 635 code | 184 blank | 388 comment | 140 complexity | b4be7f8d97bd256833143aef7e9c40a8 MD5 | raw file
   1/*********************************************************************
   2 *
   3 * Filename:      irlap.c
   4 * Version:       1.0
   5 * Description:   IrLAP implementation for Linux
   6 * Status:        Stable
   7 * Author:        Dag Brattli <dagb@cs.uit.no>
   8 * Created at:    Mon Aug  4 20:40:53 1997
   9 * Modified at:   Tue Dec 14 09:26:44 1999
  10 * Modified by:   Dag Brattli <dagb@cs.uit.no>
  11 *
  12 *     Copyright (c) 1998-1999 Dag Brattli, All Rights Reserved.
  13 *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
  14 *
  15 *     This program is free software; you can redistribute it and/or
  16 *     modify it under the terms of the GNU General Public License as
  17 *     published by the Free Software Foundation; either version 2 of
  18 *     the License, or (at your option) any later version.
  19 *
  20 *     This program is distributed in the hope that it will be useful,
  21 *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  23 *     GNU General Public License for more details.
  24 *
  25 *     You should have received a copy of the GNU General Public License
  26 *     along with this program; if not, see <http://www.gnu.org/licenses/>.
  27 *
  28 ********************************************************************/
  29
  30#include <linux/slab.h>
  31#include <linux/string.h>
  32#include <linux/skbuff.h>
  33#include <linux/delay.h>
  34#include <linux/proc_fs.h>
  35#include <linux/init.h>
  36#include <linux/random.h>
  37#include <linux/module.h>
  38#include <linux/seq_file.h>
  39
  40#include <net/irda/irda.h>
  41#include <net/irda/irda_device.h>
  42#include <net/irda/irqueue.h>
  43#include <net/irda/irlmp.h>
  44#include <net/irda/irlmp_frame.h>
  45#include <net/irda/irlap_frame.h>
  46#include <net/irda/irlap.h>
  47#include <net/irda/timer.h>
  48#include <net/irda/qos.h>
  49
  50static hashbin_t *irlap = NULL;
  51int sysctl_slot_timeout = SLOT_TIMEOUT * 1000 / HZ;
  52
  53/* This is the delay of missed pf period before generating an event
  54 * to the application. The spec mandate 3 seconds, but in some cases
  55 * it's way too long. - Jean II */
  56int sysctl_warn_noreply_time = 3;
  57
  58extern void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb);
  59static void __irlap_close(struct irlap_cb *self);
  60static void irlap_init_qos_capabilities(struct irlap_cb *self,
  61					struct qos_info *qos_user);
  62
  63static const char *const lap_reasons[] __maybe_unused = {
  64	"ERROR, NOT USED",
  65	"LAP_DISC_INDICATION",
  66	"LAP_NO_RESPONSE",
  67	"LAP_RESET_INDICATION",
  68	"LAP_FOUND_NONE",
  69	"LAP_MEDIA_BUSY",
  70	"LAP_PRIMARY_CONFLICT",
  71	"ERROR, NOT USED",
  72};
  73
  74int __init irlap_init(void)
  75{
  76	/* Check if the compiler did its job properly.
  77	 * May happen on some ARM configuration, check with Russell King. */
  78	IRDA_ASSERT(sizeof(struct xid_frame) == 14, ;);
  79	IRDA_ASSERT(sizeof(struct test_frame) == 10, ;);
  80	IRDA_ASSERT(sizeof(struct ua_frame) == 10, ;);
  81	IRDA_ASSERT(sizeof(struct snrm_frame) == 11, ;);
  82
  83	/* Allocate master array */
  84	irlap = hashbin_new(HB_LOCK);
  85	if (irlap == NULL) {
  86		net_err_ratelimited("%s: can't allocate irlap hashbin!\n",
  87				    __func__);
  88		return -ENOMEM;
  89	}
  90
  91	return 0;
  92}
  93
  94void irlap_cleanup(void)
  95{
  96	IRDA_ASSERT(irlap != NULL, return;);
  97
  98	hashbin_delete(irlap, (FREE_FUNC) __irlap_close);
  99}
 100
 101/*
 102 * Function irlap_open (driver)
 103 *
 104 *    Initialize IrLAP layer
 105 *
 106 */
 107struct irlap_cb *irlap_open(struct net_device *dev, struct qos_info *qos,
 108			    const char *hw_name)
 109{
 110	struct irlap_cb *self;
 111
 112	/* Initialize the irlap structure. */
 113	self = kzalloc(sizeof(struct irlap_cb), GFP_KERNEL);
 114	if (self == NULL)
 115		return NULL;
 116
 117	self->magic = LAP_MAGIC;
 118
 119	/* Make a binding between the layers */
 120	self->netdev = dev;
 121	self->qos_dev = qos;
 122	/* Copy hardware name */
 123	if(hw_name != NULL) {
 124		strlcpy(self->hw_name, hw_name, sizeof(self->hw_name));
 125	} else {
 126		self->hw_name[0] = '\0';
 127	}
 128
 129	/* FIXME: should we get our own field? */
 130	dev->atalk_ptr = self;
 131
 132	self->state = LAP_OFFLINE;
 133
 134	/* Initialize transmit queue */
 135	skb_queue_head_init(&self->txq);
 136	skb_queue_head_init(&self->txq_ultra);
 137	skb_queue_head_init(&self->wx_list);
 138
 139	/* My unique IrLAP device address! */
 140	/* We don't want the broadcast address, neither the NULL address
 141	 * (most often used to signify "invalid"), and we don't want an
 142	 * address already in use (otherwise connect won't be able
 143	 * to select the proper link). - Jean II */
 144	do {
 145		get_random_bytes(&self->saddr, sizeof(self->saddr));
 146	} while ((self->saddr == 0x0) || (self->saddr == BROADCAST) ||
 147		 (hashbin_lock_find(irlap, self->saddr, NULL)) );
 148	/* Copy to the driver */
 149	memcpy(dev->dev_addr, &self->saddr, 4);
 150
 151	init_timer(&self->slot_timer);
 152	init_timer(&self->query_timer);
 153	init_timer(&self->discovery_timer);
 154	init_timer(&self->final_timer);
 155	init_timer(&self->poll_timer);
 156	init_timer(&self->wd_timer);
 157	init_timer(&self->backoff_timer);
 158	init_timer(&self->media_busy_timer);
 159
 160	irlap_apply_default_connection_parameters(self);
 161
 162	self->N3 = 3; /* # connections attempts to try before giving up */
 163
 164	self->state = LAP_NDM;
 165
 166	hashbin_insert(irlap, (irda_queue_t *) self, self->saddr, NULL);
 167
 168	irlmp_register_link(self, self->saddr, &self->notify);
 169
 170	return self;
 171}
 172EXPORT_SYMBOL(irlap_open);
 173
 174/*
 175 * Function __irlap_close (self)
 176 *
 177 *    Remove IrLAP and all allocated memory. Stop any pending timers.
 178 *
 179 */
 180static void __irlap_close(struct irlap_cb *self)
 181{
 182	IRDA_ASSERT(self != NULL, return;);
 183	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 184
 185	/* Stop timers */
 186	del_timer(&self->slot_timer);
 187	del_timer(&self->query_timer);
 188	del_timer(&self->discovery_timer);
 189	del_timer(&self->final_timer);
 190	del_timer(&self->poll_timer);
 191	del_timer(&self->wd_timer);
 192	del_timer(&self->backoff_timer);
 193	del_timer(&self->media_busy_timer);
 194
 195	irlap_flush_all_queues(self);
 196
 197	self->magic = 0;
 198
 199	kfree(self);
 200}
 201
 202/*
 203 * Function irlap_close (self)
 204 *
 205 *    Remove IrLAP instance
 206 *
 207 */
 208void irlap_close(struct irlap_cb *self)
 209{
 210	struct irlap_cb *lap;
 211
 212	IRDA_ASSERT(self != NULL, return;);
 213	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 214
 215	/* We used to send a LAP_DISC_INDICATION here, but this was
 216	 * racy. This has been move within irlmp_unregister_link()
 217	 * itself. Jean II */
 218
 219	/* Kill the LAP and all LSAPs on top of it */
 220	irlmp_unregister_link(self->saddr);
 221	self->notify.instance = NULL;
 222
 223	/* Be sure that we manage to remove ourself from the hash */
 224	lap = hashbin_remove(irlap, self->saddr, NULL);
 225	if (!lap) {
 226		pr_debug("%s(), Didn't find myself!\n", __func__);
 227		return;
 228	}
 229	__irlap_close(lap);
 230}
 231EXPORT_SYMBOL(irlap_close);
 232
 233/*
 234 * Function irlap_connect_indication (self, skb)
 235 *
 236 *    Another device is attempting to make a connection
 237 *
 238 */
 239void irlap_connect_indication(struct irlap_cb *self, struct sk_buff *skb)
 240{
 241	IRDA_ASSERT(self != NULL, return;);
 242	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 243
 244	irlap_init_qos_capabilities(self, NULL); /* No user QoS! */
 245
 246	irlmp_link_connect_indication(self->notify.instance, self->saddr,
 247				      self->daddr, &self->qos_tx, skb);
 248}
 249
 250/*
 251 * Function irlap_connect_response (self, skb)
 252 *
 253 *    Service user has accepted incoming connection
 254 *
 255 */
 256void irlap_connect_response(struct irlap_cb *self, struct sk_buff *userdata)
 257{
 258	irlap_do_event(self, CONNECT_RESPONSE, userdata, NULL);
 259}
 260
 261/*
 262 * Function irlap_connect_request (self, daddr, qos_user, sniff)
 263 *
 264 *    Request connection with another device, sniffing is not implemented
 265 *    yet.
 266 *
 267 */
 268void irlap_connect_request(struct irlap_cb *self, __u32 daddr,
 269			   struct qos_info *qos_user, int sniff)
 270{
 271	pr_debug("%s(), daddr=0x%08x\n", __func__, daddr);
 272
 273	IRDA_ASSERT(self != NULL, return;);
 274	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 275
 276	self->daddr = daddr;
 277
 278	/*
 279	 *  If the service user specifies QoS values for this connection,
 280	 *  then use them
 281	 */
 282	irlap_init_qos_capabilities(self, qos_user);
 283
 284	if ((self->state == LAP_NDM) && !self->media_busy)
 285		irlap_do_event(self, CONNECT_REQUEST, NULL, NULL);
 286	else
 287		self->connect_pending = TRUE;
 288}
 289
 290/*
 291 * Function irlap_connect_confirm (self, skb)
 292 *
 293 *    Connection request has been accepted
 294 *
 295 */
 296void irlap_connect_confirm(struct irlap_cb *self, struct sk_buff *skb)
 297{
 298	IRDA_ASSERT(self != NULL, return;);
 299	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 300
 301	irlmp_link_connect_confirm(self->notify.instance, &self->qos_tx, skb);
 302}
 303
 304/*
 305 * Function irlap_data_indication (self, skb)
 306 *
 307 *    Received data frames from IR-port, so we just pass them up to
 308 *    IrLMP for further processing
 309 *
 310 */
 311void irlap_data_indication(struct irlap_cb *self, struct sk_buff *skb,
 312			   int unreliable)
 313{
 314	/* Hide LAP header from IrLMP layer */
 315	skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
 316
 317	irlmp_link_data_indication(self->notify.instance, skb, unreliable);
 318}
 319
 320
 321/*
 322 * Function irlap_data_request (self, skb)
 323 *
 324 *    Queue data for transmission, must wait until XMIT state
 325 *
 326 */
 327void irlap_data_request(struct irlap_cb *self, struct sk_buff *skb,
 328			int unreliable)
 329{
 330	IRDA_ASSERT(self != NULL, return;);
 331	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 332
 333	IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
 334		    return;);
 335	skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
 336
 337	/*
 338	 *  Must set frame format now so that the rest of the code knows
 339	 *  if its dealing with an I or an UI frame
 340	 */
 341	if (unreliable)
 342		skb->data[1] = UI_FRAME;
 343	else
 344		skb->data[1] = I_FRAME;
 345
 346	/* Don't forget to refcount it - see irlmp_connect_request(). */
 347	skb_get(skb);
 348
 349	/* Add at the end of the queue (keep ordering) - Jean II */
 350	skb_queue_tail(&self->txq, skb);
 351
 352	/*
 353	 *  Send event if this frame only if we are in the right state
 354	 *  FIXME: udata should be sent first! (skb_queue_head?)
 355	 */
 356	if ((self->state == LAP_XMIT_P) || (self->state == LAP_XMIT_S)) {
 357		/* If we are not already processing the Tx queue, trigger
 358		 * transmission immediately - Jean II */
 359		if((skb_queue_len(&self->txq) <= 1) && (!self->local_busy))
 360			irlap_do_event(self, DATA_REQUEST, skb, NULL);
 361		/* Otherwise, the packets will be sent normally at the
 362		 * next pf-poll - Jean II */
 363	}
 364}
 365
 366/*
 367 * Function irlap_unitdata_request (self, skb)
 368 *
 369 *    Send Ultra data. This is data that must be sent outside any connection
 370 *
 371 */
 372#ifdef CONFIG_IRDA_ULTRA
 373void irlap_unitdata_request(struct irlap_cb *self, struct sk_buff *skb)
 374{
 375	IRDA_ASSERT(self != NULL, return;);
 376	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 377
 378	IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
 379	       return;);
 380	skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
 381
 382	skb->data[0] = CBROADCAST;
 383	skb->data[1] = UI_FRAME;
 384
 385	/* Don't need to refcount, see irlmp_connless_data_request() */
 386
 387	skb_queue_tail(&self->txq_ultra, skb);
 388
 389	irlap_do_event(self, SEND_UI_FRAME, NULL, NULL);
 390}
 391#endif /*CONFIG_IRDA_ULTRA */
 392
 393/*
 394 * Function irlap_udata_indication (self, skb)
 395 *
 396 *    Receive Ultra data. This is data that is received outside any connection
 397 *
 398 */
 399#ifdef CONFIG_IRDA_ULTRA
 400void irlap_unitdata_indication(struct irlap_cb *self, struct sk_buff *skb)
 401{
 402	IRDA_ASSERT(self != NULL, return;);
 403	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 404	IRDA_ASSERT(skb != NULL, return;);
 405
 406	/* Hide LAP header from IrLMP layer */
 407	skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
 408
 409	irlmp_link_unitdata_indication(self->notify.instance, skb);
 410}
 411#endif /* CONFIG_IRDA_ULTRA */
 412
 413/*
 414 * Function irlap_disconnect_request (void)
 415 *
 416 *    Request to disconnect connection by service user
 417 */
 418void irlap_disconnect_request(struct irlap_cb *self)
 419{
 420	IRDA_ASSERT(self != NULL, return;);
 421	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 422
 423	/* Don't disconnect until all data frames are successfully sent */
 424	if (!skb_queue_empty(&self->txq)) {
 425		self->disconnect_pending = TRUE;
 426		return;
 427	}
 428
 429	/* Check if we are in the right state for disconnecting */
 430	switch (self->state) {
 431	case LAP_XMIT_P:        /* FALLTHROUGH */
 432	case LAP_XMIT_S:        /* FALLTHROUGH */
 433	case LAP_CONN:          /* FALLTHROUGH */
 434	case LAP_RESET_WAIT:    /* FALLTHROUGH */
 435	case LAP_RESET_CHECK:
 436		irlap_do_event(self, DISCONNECT_REQUEST, NULL, NULL);
 437		break;
 438	default:
 439		pr_debug("%s(), disconnect pending!\n", __func__);
 440		self->disconnect_pending = TRUE;
 441		break;
 442	}
 443}
 444
 445/*
 446 * Function irlap_disconnect_indication (void)
 447 *
 448 *    Disconnect request from other device
 449 *
 450 */
 451void irlap_disconnect_indication(struct irlap_cb *self, LAP_REASON reason)
 452{
 453	pr_debug("%s(), reason=%s\n", __func__, lap_reasons[reason]);
 454
 455	IRDA_ASSERT(self != NULL, return;);
 456	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 457
 458	/* Flush queues */
 459	irlap_flush_all_queues(self);
 460
 461	switch (reason) {
 462	case LAP_RESET_INDICATION:
 463		pr_debug("%s(), Sending reset request!\n", __func__);
 464		irlap_do_event(self, RESET_REQUEST, NULL, NULL);
 465		break;
 466	case LAP_NO_RESPONSE:	   /* FALLTHROUGH */
 467	case LAP_DISC_INDICATION:  /* FALLTHROUGH */
 468	case LAP_FOUND_NONE:       /* FALLTHROUGH */
 469	case LAP_MEDIA_BUSY:
 470		irlmp_link_disconnect_indication(self->notify.instance, self,
 471						 reason, NULL);
 472		break;
 473	default:
 474		net_err_ratelimited("%s: Unknown reason %d\n",
 475				    __func__, reason);
 476	}
 477}
 478
 479/*
 480 * Function irlap_discovery_request (gen_addr_bit)
 481 *
 482 *    Start one single discovery operation.
 483 *
 484 */
 485void irlap_discovery_request(struct irlap_cb *self, discovery_t *discovery)
 486{
 487	struct irlap_info info;
 488
 489	IRDA_ASSERT(self != NULL, return;);
 490	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 491	IRDA_ASSERT(discovery != NULL, return;);
 492
 493	pr_debug("%s(), nslots = %d\n", __func__, discovery->nslots);
 494
 495	IRDA_ASSERT((discovery->nslots == 1) || (discovery->nslots == 6) ||
 496		    (discovery->nslots == 8) || (discovery->nslots == 16),
 497		    return;);
 498
 499	/* Discovery is only possible in NDM mode */
 500	if (self->state != LAP_NDM) {
 501		pr_debug("%s(), discovery only possible in NDM mode\n",
 502			 __func__);
 503		irlap_discovery_confirm(self, NULL);
 504		/* Note : in theory, if we are not in NDM, we could postpone
 505		 * the discovery like we do for connection request.
 506		 * In practice, it's not worth it. If the media was busy,
 507		 * it's likely next time around it won't be busy. If we are
 508		 * in REPLY state, we will get passive discovery info & event.
 509		 * Jean II */
 510		return;
 511	}
 512
 513	/* Check if last discovery request finished in time, or if
 514	 * it was aborted due to the media busy flag. */
 515	if (self->discovery_log != NULL) {
 516		hashbin_delete(self->discovery_log, (FREE_FUNC) kfree);
 517		self->discovery_log = NULL;
 518	}
 519
 520	/* All operations will occur at predictable time, no need to lock */
 521	self->discovery_log = hashbin_new(HB_NOLOCK);
 522
 523	if (self->discovery_log == NULL) {
 524		net_warn_ratelimited("%s(), Unable to allocate discovery log!\n",
 525				     __func__);
 526		return;
 527	}
 528
 529	info.S = discovery->nslots; /* Number of slots */
 530	info.s = 0; /* Current slot */
 531
 532	self->discovery_cmd = discovery;
 533	info.discovery = discovery;
 534
 535	/* sysctl_slot_timeout bounds are checked in irsysctl.c - Jean II */
 536	self->slot_timeout = msecs_to_jiffies(sysctl_slot_timeout);
 537
 538	irlap_do_event(self, DISCOVERY_REQUEST, NULL, &info);
 539}
 540
 541/*
 542 * Function irlap_discovery_confirm (log)
 543 *
 544 *    A device has been discovered in front of this station, we
 545 *    report directly to LMP.
 546 */
 547void irlap_discovery_confirm(struct irlap_cb *self, hashbin_t *discovery_log)
 548{
 549	IRDA_ASSERT(self != NULL, return;);
 550	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 551
 552	IRDA_ASSERT(self->notify.instance != NULL, return;);
 553
 554	/*
 555	 * Check for successful discovery, since we are then allowed to clear
 556	 * the media busy condition (IrLAP 6.13.4 - p.94). This should allow
 557	 * us to make connection attempts much faster and easier (i.e. no
 558	 * collisions).
 559	 * Setting media busy to false will also generate an event allowing
 560	 * to process pending events in NDM state machine.
 561	 * Note : the spec doesn't define what's a successful discovery is.
 562	 * If we want Ultra to work, it's successful even if there is
 563	 * nobody discovered - Jean II
 564	 */
 565	if (discovery_log)
 566		irda_device_set_media_busy(self->netdev, FALSE);
 567
 568	/* Inform IrLMP */
 569	irlmp_link_discovery_confirm(self->notify.instance, discovery_log);
 570}
 571
 572/*
 573 * Function irlap_discovery_indication (log)
 574 *
 575 *    Somebody is trying to discover us!
 576 *
 577 */
 578void irlap_discovery_indication(struct irlap_cb *self, discovery_t *discovery)
 579{
 580	IRDA_ASSERT(self != NULL, return;);
 581	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 582	IRDA_ASSERT(discovery != NULL, return;);
 583
 584	IRDA_ASSERT(self->notify.instance != NULL, return;);
 585
 586	/* A device is very likely to connect immediately after it performs
 587	 * a successful discovery. This means that in our case, we are much
 588	 * more likely to receive a connection request over the medium.
 589	 * So, we backoff to avoid collisions.
 590	 * IrLAP spec 6.13.4 suggest 100ms...
 591	 * Note : this little trick actually make a *BIG* difference. If I set
 592	 * my Linux box with discovery enabled and one Ultra frame sent every
 593	 * second, my Palm has no trouble connecting to it every time !
 594	 * Jean II */
 595	irda_device_set_media_busy(self->netdev, SMALL);
 596
 597	irlmp_link_discovery_indication(self->notify.instance, discovery);
 598}
 599
 600/*
 601 * Function irlap_status_indication (quality_of_link)
 602 */
 603void irlap_status_indication(struct irlap_cb *self, int quality_of_link)
 604{
 605	switch (quality_of_link) {
 606	case STATUS_NO_ACTIVITY:
 607		net_info_ratelimited("IrLAP, no activity on link!\n");
 608		break;
 609	case STATUS_NOISY:
 610		net_info_ratelimited("IrLAP, noisy link!\n");
 611		break;
 612	default:
 613		break;
 614	}
 615	irlmp_status_indication(self->notify.instance,
 616				quality_of_link, LOCK_NO_CHANGE);
 617}
 618
 619/*
 620 * Function irlap_reset_indication (void)
 621 */
 622void irlap_reset_indication(struct irlap_cb *self)
 623{
 624	IRDA_ASSERT(self != NULL, return;);
 625	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 626
 627	if (self->state == LAP_RESET_WAIT)
 628		irlap_do_event(self, RESET_REQUEST, NULL, NULL);
 629	else
 630		irlap_do_event(self, RESET_RESPONSE, NULL, NULL);
 631}
 632
 633/*
 634 * Function irlap_reset_confirm (void)
 635 */
 636void irlap_reset_confirm(void)
 637{
 638}
 639
 640/*
 641 * Function irlap_generate_rand_time_slot (S, s)
 642 *
 643 *    Generate a random time slot between s and S-1 where
 644 *    S = Number of slots (0 -> S-1)
 645 *    s = Current slot
 646 */
 647int irlap_generate_rand_time_slot(int S, int s)
 648{
 649	static int rand;
 650	int slot;
 651
 652	IRDA_ASSERT((S - s) > 0, return 0;);
 653
 654	rand += jiffies;
 655	rand ^= (rand << 12);
 656	rand ^= (rand >> 20);
 657
 658	slot = s + rand % (S-s);
 659
 660	IRDA_ASSERT((slot >= s) || (slot < S), return 0;);
 661
 662	return slot;
 663}
 664
 665/*
 666 * Function irlap_update_nr_received (nr)
 667 *
 668 *    Remove all acknowledged frames in current window queue. This code is
 669 *    not intuitive and you should not try to change it. If you think it
 670 *    contains bugs, please mail a patch to the author instead.
 671 */
 672void irlap_update_nr_received(struct irlap_cb *self, int nr)
 673{
 674	struct sk_buff *skb = NULL;
 675	int count = 0;
 676
 677	/*
 678	 * Remove all the ack-ed frames from the window queue.
 679	 */
 680
 681	/*
 682	 *  Optimize for the common case. It is most likely that the receiver
 683	 *  will acknowledge all the frames we have sent! So in that case we
 684	 *  delete all frames stored in window.
 685	 */
 686	if (nr == self->vs) {
 687		while ((skb = skb_dequeue(&self->wx_list)) != NULL) {
 688			dev_kfree_skb(skb);
 689		}
 690		/* The last acked frame is the next to send minus one */
 691		self->va = nr - 1;
 692	} else {
 693		/* Remove all acknowledged frames in current window */
 694		while ((skb_peek(&self->wx_list) != NULL) &&
 695		       (((self->va+1) % 8) != nr))
 696		{
 697			skb = skb_dequeue(&self->wx_list);
 698			dev_kfree_skb(skb);
 699
 700			self->va = (self->va + 1) % 8;
 701			count++;
 702		}
 703	}
 704
 705	/* Advance window */
 706	self->window = self->window_size - skb_queue_len(&self->wx_list);
 707}
 708
 709/*
 710 * Function irlap_validate_ns_received (ns)
 711 *
 712 *    Validate the next to send (ns) field from received frame.
 713 */
 714int irlap_validate_ns_received(struct irlap_cb *self, int ns)
 715{
 716	/*  ns as expected?  */
 717	if (ns == self->vr)
 718		return NS_EXPECTED;
 719	/*
 720	 *  Stations are allowed to treat invalid NS as unexpected NS
 721	 *  IrLAP, Recv ... with-invalid-Ns. p. 84
 722	 */
 723	return NS_UNEXPECTED;
 724
 725	/* return NR_INVALID; */
 726}
 727/*
 728 * Function irlap_validate_nr_received (nr)
 729 *
 730 *    Validate the next to receive (nr) field from received frame.
 731 *
 732 */
 733int irlap_validate_nr_received(struct irlap_cb *self, int nr)
 734{
 735	/*  nr as expected?  */
 736	if (nr == self->vs) {
 737		pr_debug("%s(), expected!\n", __func__);
 738		return NR_EXPECTED;
 739	}
 740
 741	/*
 742	 *  unexpected nr? (but within current window), first we check if the
 743	 *  ns numbers of the frames in the current window wrap.
 744	 */
 745	if (self->va < self->vs) {
 746		if ((nr >= self->va) && (nr <= self->vs))
 747			return NR_UNEXPECTED;
 748	} else {
 749		if ((nr >= self->va) || (nr <= self->vs))
 750			return NR_UNEXPECTED;
 751	}
 752
 753	/* Invalid nr!  */
 754	return NR_INVALID;
 755}
 756
 757/*
 758 * Function irlap_initiate_connection_state ()
 759 *
 760 *    Initialize the connection state parameters
 761 *
 762 */
 763void irlap_initiate_connection_state(struct irlap_cb *self)
 764{
 765	IRDA_ASSERT(self != NULL, return;);
 766	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 767
 768	/* Next to send and next to receive */
 769	self->vs = self->vr = 0;
 770
 771	/* Last frame which got acked (0 - 1) % 8 */
 772	self->va = 7;
 773
 774	self->window = 1;
 775
 776	self->remote_busy = FALSE;
 777	self->retry_count = 0;
 778}
 779
 780/*
 781 * Function irlap_wait_min_turn_around (self, qos)
 782 *
 783 *    Wait negotiated minimum turn around time, this function actually sets
 784 *    the number of BOS's that must be sent before the next transmitted
 785 *    frame in order to delay for the specified amount of time. This is
 786 *    done to avoid using timers, and the forbidden udelay!
 787 */
 788void irlap_wait_min_turn_around(struct irlap_cb *self, struct qos_info *qos)
 789{
 790	__u32 min_turn_time;
 791	__u32 speed;
 792
 793	/* Get QoS values.  */
 794	speed = qos->baud_rate.value;
 795	min_turn_time = qos->min_turn_time.value;
 796
 797	/* No need to calculate XBOFs for speeds over 115200 bps */
 798	if (speed > 115200) {
 799		self->mtt_required = min_turn_time;
 800		return;
 801	}
 802
 803	/*
 804	 *  Send additional BOF's for the next frame for the requested
 805	 *  min turn time, so now we must calculate how many chars (XBOF's) we
 806	 *  must send for the requested time period (min turn time)
 807	 */
 808	self->xbofs_delay = irlap_min_turn_time_in_bytes(speed, min_turn_time);
 809}
 810
 811/*
 812 * Function irlap_flush_all_queues (void)
 813 *
 814 *    Flush all queues
 815 *
 816 */
 817void irlap_flush_all_queues(struct irlap_cb *self)
 818{
 819	struct sk_buff* skb;
 820
 821	IRDA_ASSERT(self != NULL, return;);
 822	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 823
 824	/* Free transmission queue */
 825	while ((skb = skb_dequeue(&self->txq)) != NULL)
 826		dev_kfree_skb(skb);
 827
 828	while ((skb = skb_dequeue(&self->txq_ultra)) != NULL)
 829		dev_kfree_skb(skb);
 830
 831	/* Free sliding window buffered packets */
 832	while ((skb = skb_dequeue(&self->wx_list)) != NULL)
 833		dev_kfree_skb(skb);
 834}
 835
 836/*
 837 * Function irlap_setspeed (self, speed)
 838 *
 839 *    Change the speed of the IrDA port
 840 *
 841 */
 842static void irlap_change_speed(struct irlap_cb *self, __u32 speed, int now)
 843{
 844	struct sk_buff *skb;
 845
 846	pr_debug("%s(), setting speed to %d\n", __func__, speed);
 847
 848	IRDA_ASSERT(self != NULL, return;);
 849	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 850
 851	self->speed = speed;
 852
 853	/* Change speed now, or just piggyback speed on frames */
 854	if (now) {
 855		/* Send down empty frame to trigger speed change */
 856		skb = alloc_skb(0, GFP_ATOMIC);
 857		if (skb)
 858			irlap_queue_xmit(self, skb);
 859	}
 860}
 861
 862/*
 863 * Function irlap_init_qos_capabilities (self, qos)
 864 *
 865 *    Initialize QoS for this IrLAP session, What we do is to compute the
 866 *    intersection of the QoS capabilities for the user, driver and for
 867 *    IrLAP itself. Normally, IrLAP will not specify any values, but it can
 868 *    be used to restrict certain values.
 869 */
 870static void irlap_init_qos_capabilities(struct irlap_cb *self,
 871					struct qos_info *qos_user)
 872{
 873	IRDA_ASSERT(self != NULL, return;);
 874	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 875	IRDA_ASSERT(self->netdev != NULL, return;);
 876
 877	/* Start out with the maximum QoS support possible */
 878	irda_init_max_qos_capabilies(&self->qos_rx);
 879
 880	/* Apply drivers QoS capabilities */
 881	irda_qos_compute_intersection(&self->qos_rx, self->qos_dev);
 882
 883	/*
 884	 *  Check for user supplied QoS parameters. The service user is only
 885	 *  allowed to supply these values. We check each parameter since the
 886	 *  user may not have set all of them.
 887	 */
 888	if (qos_user) {
 889		pr_debug("%s(), Found user specified QoS!\n", __func__);
 890
 891		if (qos_user->baud_rate.bits)
 892			self->qos_rx.baud_rate.bits &= qos_user->baud_rate.bits;
 893
 894		if (qos_user->max_turn_time.bits)
 895			self->qos_rx.max_turn_time.bits &= qos_user->max_turn_time.bits;
 896		if (qos_user->data_size.bits)
 897			self->qos_rx.data_size.bits &= qos_user->data_size.bits;
 898
 899		if (qos_user->link_disc_time.bits)
 900			self->qos_rx.link_disc_time.bits &= qos_user->link_disc_time.bits;
 901	}
 902
 903	/* Use 500ms in IrLAP for now */
 904	self->qos_rx.max_turn_time.bits &= 0x01;
 905
 906	/* Set data size */
 907	/*self->qos_rx.data_size.bits &= 0x03;*/
 908
 909	irda_qos_bits_to_value(&self->qos_rx);
 910}
 911
 912/*
 913 * Function irlap_apply_default_connection_parameters (void, now)
 914 *
 915 *    Use the default connection and transmission parameters
 916 */
 917void irlap_apply_default_connection_parameters(struct irlap_cb *self)
 918{
 919	IRDA_ASSERT(self != NULL, return;);
 920	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 921
 922	/* xbofs : Default value in NDM */
 923	self->next_bofs   = 12;
 924	self->bofs_count  = 12;
 925
 926	/* NDM Speed is 9600 */
 927	irlap_change_speed(self, 9600, TRUE);
 928
 929	/* Set mbusy when going to NDM state */
 930	irda_device_set_media_busy(self->netdev, TRUE);
 931
 932	/*
 933	 * Generate random connection address for this session, which must
 934	 * be 7 bits wide and different from 0x00 and 0xfe
 935	 */
 936	while ((self->caddr == 0x00) || (self->caddr == 0xfe)) {
 937		get_random_bytes(&self->caddr, sizeof(self->caddr));
 938		self->caddr &= 0xfe;
 939	}
 940
 941	/* Use default values until connection has been negitiated */
 942	self->slot_timeout = sysctl_slot_timeout;
 943	self->final_timeout = FINAL_TIMEOUT;
 944	self->poll_timeout = POLL_TIMEOUT;
 945	self->wd_timeout = WD_TIMEOUT;
 946
 947	/* Set some default values */
 948	self->qos_tx.baud_rate.value = 9600;
 949	self->qos_rx.baud_rate.value = 9600;
 950	self->qos_tx.max_turn_time.value = 0;
 951	self->qos_rx.max_turn_time.value = 0;
 952	self->qos_tx.min_turn_time.value = 0;
 953	self->qos_rx.min_turn_time.value = 0;
 954	self->qos_tx.data_size.value = 64;
 955	self->qos_rx.data_size.value = 64;
 956	self->qos_tx.window_size.value = 1;
 957	self->qos_rx.window_size.value = 1;
 958	self->qos_tx.additional_bofs.value = 12;
 959	self->qos_rx.additional_bofs.value = 12;
 960	self->qos_tx.link_disc_time.value = 0;
 961	self->qos_rx.link_disc_time.value = 0;
 962
 963	irlap_flush_all_queues(self);
 964
 965	self->disconnect_pending = FALSE;
 966	self->connect_pending = FALSE;
 967}
 968
 969/*
 970 * Function irlap_apply_connection_parameters (qos, now)
 971 *
 972 *    Initialize IrLAP with the negotiated QoS values
 973 *
 974 * If 'now' is false, the speed and xbofs will be changed after the next
 975 * frame is sent.
 976 * If 'now' is true, the speed and xbofs is changed immediately
 977 */
 978void irlap_apply_connection_parameters(struct irlap_cb *self, int now)
 979{
 980	IRDA_ASSERT(self != NULL, return;);
 981	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
 982
 983	/* Set the negotiated xbofs value */
 984	self->next_bofs   = self->qos_tx.additional_bofs.value;
 985	if (now)
 986		self->bofs_count = self->next_bofs;
 987
 988	/* Set the negotiated link speed (may need the new xbofs value) */
 989	irlap_change_speed(self, self->qos_tx.baud_rate.value, now);
 990
 991	self->window_size = self->qos_tx.window_size.value;
 992	self->window      = self->qos_tx.window_size.value;
 993
 994#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
 995	/*
 996	 *  Calculate how many bytes it is possible to transmit before the
 997	 *  link must be turned around
 998	 */
 999	self->line_capacity =
1000		irlap_max_line_capacity(self->qos_tx.baud_rate.value,
1001					self->qos_tx.max_turn_time.value);
1002	self->bytes_left = self->line_capacity;
1003#endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
1004
1005
1006	/*
1007	 *  Initialize timeout values, some of the rules are listed on
1008	 *  page 92 in IrLAP.
1009	 */
1010	IRDA_ASSERT(self->qos_tx.max_turn_time.value != 0, return;);
1011	IRDA_ASSERT(self->qos_rx.max_turn_time.value != 0, return;);
1012	/* The poll timeout applies only to the primary station.
1013	 * It defines the maximum time the primary stay in XMIT mode
1014	 * before timeout and turning the link around (sending a RR).
1015	 * Or, this is how much we can keep the pf bit in primary mode.
1016	 * Therefore, it must be lower or equal than our *OWN* max turn around.
1017	 * Jean II */
1018	self->poll_timeout = msecs_to_jiffies(
1019				self->qos_tx.max_turn_time.value);
1020	/* The Final timeout applies only to the primary station.
1021	 * It defines the maximum time the primary wait (mostly in RECV mode)
1022	 * for an answer from the secondary station before polling it again.
1023	 * Therefore, it must be greater or equal than our *PARTNER*
1024	 * max turn around time - Jean II */
1025	self->final_timeout = msecs_to_jiffies(
1026				self->qos_rx.max_turn_time.value);
1027	/* The Watchdog Bit timeout applies only to the secondary station.
1028	 * It defines the maximum time the secondary wait (mostly in RECV mode)
1029	 * for poll from the primary station before getting annoyed.
1030	 * Therefore, it must be greater or equal than our *PARTNER*
1031	 * max turn around time - Jean II */
1032	self->wd_timeout = self->final_timeout * 2;
1033
1034	/*
1035	 * N1 and N2 are maximum retry count for *both* the final timer
1036	 * and the wd timer (with a factor 2) as defined above.
1037	 * After N1 retry of a timer, we give a warning to the user.
1038	 * After N2 retry, we consider the link dead and disconnect it.
1039	 * Jean II
1040	 */
1041
1042	/*
1043	 *  Set N1 to 0 if Link Disconnect/Threshold Time = 3 and set it to
1044	 *  3 seconds otherwise. See page 71 in IrLAP for more details.
1045	 *  Actually, it's not always 3 seconds, as we allow to set
1046	 *  it via sysctl... Max maxtt is 500ms, and N1 need to be multiple
1047	 *  of 2, so 1 second is minimum we can allow. - Jean II
1048	 */
1049	if (self->qos_tx.link_disc_time.value == sysctl_warn_noreply_time)
1050		/*
1051		 * If we set N1 to 0, it will trigger immediately, which is
1052		 * not what we want. What we really want is to disable it,
1053		 * Jean II
1054		 */
1055		self->N1 = -2; /* Disable - Need to be multiple of 2*/
1056	else
1057		self->N1 = sysctl_warn_noreply_time * 1000 /
1058		  self->qos_rx.max_turn_time.value;
1059
1060	pr_debug("Setting N1 = %d\n", self->N1);
1061
1062	/* Set N2 to match our own disconnect time */
1063	self->N2 = self->qos_tx.link_disc_time.value * 1000 /
1064		self->qos_rx.max_turn_time.value;
1065	pr_debug("Setting N2 = %d\n", self->N2);
1066}
1067
1068#ifdef CONFIG_PROC_FS
1069struct irlap_iter_state {
1070	int id;
1071};
1072
1073static void *irlap_seq_start(struct seq_file *seq, loff_t *pos)
1074{
1075	struct irlap_iter_state *iter = seq->private;
1076	struct irlap_cb *self;
1077
1078	/* Protect our access to the tsap list */
1079	spin_lock_irq(&irlap->hb_spinlock);
1080	iter->id = 0;
1081
1082	for (self = (struct irlap_cb *) hashbin_get_first(irlap);
1083	     self; self = (struct irlap_cb *) hashbin_get_next(irlap)) {
1084		if (iter->id == *pos)
1085			break;
1086		++iter->id;
1087	}
1088
1089	return self;
1090}
1091
1092static void *irlap_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1093{
1094	struct irlap_iter_state *iter = seq->private;
1095
1096	++*pos;
1097	++iter->id;
1098	return (void *) hashbin_get_next(irlap);
1099}
1100
1101static void irlap_seq_stop(struct seq_file *seq, void *v)
1102{
1103	spin_unlock_irq(&irlap->hb_spinlock);
1104}
1105
1106static int irlap_seq_show(struct seq_file *seq, void *v)
1107{
1108	const struct irlap_iter_state *iter = seq->private;
1109	const struct irlap_cb *self = v;
1110
1111	IRDA_ASSERT(self->magic == LAP_MAGIC, return -EINVAL;);
1112
1113	seq_printf(seq, "irlap%d ", iter->id);
1114	seq_printf(seq, "state: %s\n",
1115		   irlap_state[self->state]);
1116
1117	seq_printf(seq, "  device name: %s, ",
1118		   (self->netdev) ? self->netdev->name : "bug");
1119	seq_printf(seq, "hardware name: %s\n", self->hw_name);
1120
1121	seq_printf(seq, "  caddr: %#02x, ", self->caddr);
1122	seq_printf(seq, "saddr: %#08x, ", self->saddr);
1123	seq_printf(seq, "daddr: %#08x\n", self->daddr);
1124
1125	seq_printf(seq, "  win size: %d, ",
1126		   self->window_size);
1127	seq_printf(seq, "win: %d, ", self->window);
1128#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
1129	seq_printf(seq, "line capacity: %d, ",
1130		   self->line_capacity);
1131	seq_printf(seq, "bytes left: %d\n", self->bytes_left);
1132#endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
1133	seq_printf(seq, "  tx queue len: %d ",
1134		   skb_queue_len(&self->txq));
1135	seq_printf(seq, "win queue len: %d ",
1136		   skb_queue_len(&self->wx_list));
1137	seq_printf(seq, "rbusy: %s", self->remote_busy ?
1138		   "TRUE" : "FALSE");
1139	seq_printf(seq, " mbusy: %s\n", self->media_busy ?
1140		   "TRUE" : "FALSE");
1141
1142	seq_printf(seq, "  retrans: %d ", self->retry_count);
1143	seq_printf(seq, "vs: %d ", self->vs);
1144	seq_printf(seq, "vr: %d ", self->vr);
1145	seq_printf(seq, "va: %d\n", self->va);
1146
1147	seq_printf(seq, "  qos\tbps\tmaxtt\tdsize\twinsize\taddbofs\tmintt\tldisc\tcomp\n");
1148
1149	seq_printf(seq, "  tx\t%d\t",
1150		   self->qos_tx.baud_rate.value);
1151	seq_printf(seq, "%d\t",
1152		   self->qos_tx.max_turn_time.value);
1153	seq_printf(seq, "%d\t",
1154		   self->qos_tx.data_size.value);
1155	seq_printf(seq, "%d\t",
1156		   self->qos_tx.window_size.value);
1157	seq_printf(seq, "%d\t",
1158		   self->qos_tx.additional_bofs.value);
1159	seq_printf(seq, "%d\t",
1160		   self->qos_tx.min_turn_time.value);
1161	seq_printf(seq, "%d\t",
1162		   self->qos_tx.link_disc_time.value);
1163	seq_printf(seq, "\n");
1164
1165	seq_printf(seq, "  rx\t%d\t",
1166		   self->qos_rx.baud_rate.value);
1167	seq_printf(seq, "%d\t",
1168		   self->qos_rx.max_turn_time.value);
1169	seq_printf(seq, "%d\t",
1170		   self->qos_rx.data_size.value);
1171	seq_printf(seq, "%d\t",
1172		   self->qos_rx.window_size.value);
1173	seq_printf(seq, "%d\t",
1174		   self->qos_rx.additional_bofs.value);
1175	seq_printf(seq, "%d\t",
1176		   self->qos_rx.min_turn_time.value);
1177	seq_printf(seq, "%d\n",
1178		   self->qos_rx.link_disc_time.value);
1179
1180	return 0;
1181}
1182
1183static const struct seq_operations irlap_seq_ops = {
1184	.start  = irlap_seq_start,
1185	.next   = irlap_seq_next,
1186	.stop   = irlap_seq_stop,
1187	.show   = irlap_seq_show,
1188};
1189
1190static int irlap_seq_open(struct inode *inode, struct file *file)
1191{
1192	if (irlap == NULL)
1193		return -EINVAL;
1194
1195	return seq_open_private(file, &irlap_seq_ops,
1196			sizeof(struct irlap_iter_state));
1197}
1198
1199const struct file_operations irlap_seq_fops = {
1200	.owner		= THIS_MODULE,
1201	.open           = irlap_seq_open,
1202	.read           = seq_read,
1203	.llseek         = seq_lseek,
1204	.release	= seq_release_private,
1205};
1206
1207#endif /* CONFIG_PROC_FS */