/*********************************************************************
   *
   * Filename:      irlap.c
   * Version:       1.0
   * Description:   IrLAP implementation for Linux
   * Status:        Stable
   * Author:        Dag Brattli <dagb@cs.uit.no>
   * Created at:    Mon Aug  4 20:40:53 1997
   * Modified at:   Tue Dec 14 09:26:44 1999
   * Modified by:   Dag Brattli <dagb@cs.uit.no>
   *
   *     Copyright (c) 1998-1999 Dag Brattli, All Rights Reserved.
   *     Copyright (c) 2000-2003 Jean Tourrilhes <jt@hpl.hp.com>
   *
   *     This program is free software; you can redistribute it and/or
   *     modify it under the terms of the GNU General Public License as
   *     published by the Free Software Foundation; either version 2 of
   *     the License, or (at your option) any later version.
   *
   *     This program is distributed in the hope that it will be useful,
   *     but WITHOUT ANY WARRANTY; without even the implied warranty of
   *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
   *     GNU General Public License for more details.
   *
   *     You should have received a copy of the GNU General Public License

   *     along with this program; if not, see <http://www.gnu.org/licenses/>.

   *
   ********************************************************************/

  #include <linux/slab.h>
  #include <linux/string.h>
  #include <linux/skbuff.h>
  #include <linux/delay.h>
  #include <linux/proc_fs.h>
  #include <linux/init.h>
  #include <linux/random.h>
  #include <linux/module.h>
  #include <linux/seq_file.h>
  
  #include <net/irda/irda.h>
  #include <net/irda/irda_device.h>
  #include <net/irda/irqueue.h>
  #include <net/irda/irlmp.h>
  #include <net/irda/irlmp_frame.h>
  #include <net/irda/irlap_frame.h>
  #include <net/irda/irlap.h>
  #include <net/irda/timer.h>
  #include <net/irda/qos.h>
  
  static hashbin_t *irlap = NULL;
  int sysctl_slot_timeout = SLOT_TIMEOUT * 1000 / HZ;
  
  /* This is the delay of missed pf period before generating an event
   * to the application. The spec mandate 3 seconds, but in some cases
   * it's way too long. - Jean II */
  int sysctl_warn_noreply_time = 3;
  
  extern void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb);
  static void __irlap_close(struct irlap_cb *self);
  static void irlap_init_qos_capabilities(struct irlap_cb *self,
  					struct qos_info *qos_user);

  static const char *const lap_reasons[] __maybe_unused = {

  	"ERROR, NOT USED",
  	"LAP_DISC_INDICATION",
  	"LAP_NO_RESPONSE",
  	"LAP_RESET_INDICATION",
  	"LAP_FOUND_NONE",
  	"LAP_MEDIA_BUSY",
  	"LAP_PRIMARY_CONFLICT",
  	"ERROR, NOT USED",
  };

  
  int __init irlap_init(void)
  {
  	/* Check if the compiler did its job properly.
  	 * May happen on some ARM configuration, check with Russell King. */
  	IRDA_ASSERT(sizeof(struct xid_frame) == 14, ;);
  	IRDA_ASSERT(sizeof(struct test_frame) == 10, ;);
  	IRDA_ASSERT(sizeof(struct ua_frame) == 10, ;);
  	IRDA_ASSERT(sizeof(struct snrm_frame) == 11, ;);
  
  	/* Allocate master array */
  	irlap = hashbin_new(HB_LOCK);
  	if (irlap == NULL) {

  		net_err_ratelimited("%s: can't allocate irlap hashbin!
  ",
  				    __func__);

  		return -ENOMEM;
  	}
  
  	return 0;
  }

  void irlap_cleanup(void)

  {
  	IRDA_ASSERT(irlap != NULL, return;);
  
  	hashbin_delete(irlap, (FREE_FUNC) __irlap_close);
  }
  
  /*
   * Function irlap_open (driver)
   *
   *    Initialize IrLAP layer
   *
   */
  struct irlap_cb *irlap_open(struct net_device *dev, struct qos_info *qos,
  			    const char *hw_name)
  {
  	struct irlap_cb *self;

  	/* Initialize the irlap structure. */

  	self = kzalloc(sizeof(struct irlap_cb), GFP_KERNEL);

  	if (self == NULL)
  		return NULL;

  	self->magic = LAP_MAGIC;
  
  	/* Make a binding between the layers */
  	self->netdev = dev;
  	self->qos_dev = qos;
  	/* Copy hardware name */
  	if(hw_name != NULL) {
  		strlcpy(self->hw_name, hw_name, sizeof(self->hw_name));
  	} else {
  		self->hw_name[0] = '\0';
  	}
  
  	/* FIXME: should we get our own field? */
  	dev->atalk_ptr = self;
  
  	self->state = LAP_OFFLINE;
  
  	/* Initialize transmit queue */
  	skb_queue_head_init(&self->txq);
  	skb_queue_head_init(&self->txq_ultra);
  	skb_queue_head_init(&self->wx_list);
  
  	/* My unique IrLAP device address! */
  	/* We don't want the broadcast address, neither the NULL address
  	 * (most often used to signify "invalid"), and we don't want an
  	 * address already in use (otherwise connect won't be able
  	 * to select the proper link). - Jean II */
  	do {
  		get_random_bytes(&self->saddr, sizeof(self->saddr));
  	} while ((self->saddr == 0x0) || (self->saddr == BROADCAST) ||
  		 (hashbin_lock_find(irlap, self->saddr, NULL)) );
  	/* Copy to the driver */
  	memcpy(dev->dev_addr, &self->saddr, 4);
  
  	init_timer(&self->slot_timer);
  	init_timer(&self->query_timer);
  	init_timer(&self->discovery_timer);
  	init_timer(&self->final_timer);
  	init_timer(&self->poll_timer);
  	init_timer(&self->wd_timer);
  	init_timer(&self->backoff_timer);
  	init_timer(&self->media_busy_timer);
  
  	irlap_apply_default_connection_parameters(self);

  	self->N3 = 3; /* # connections attempts to try before giving up */

  
  	self->state = LAP_NDM;
  
  	hashbin_insert(irlap, (irda_queue_t *) self, self->saddr, NULL);
  
  	irlmp_register_link(self, self->saddr, &self->notify);
  
  	return self;
  }
  EXPORT_SYMBOL(irlap_open);
  
  /*
   * Function __irlap_close (self)
   *
   *    Remove IrLAP and all allocated memory. Stop any pending timers.
   *
   */
  static void __irlap_close(struct irlap_cb *self)
  {
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Stop timers */
  	del_timer(&self->slot_timer);
  	del_timer(&self->query_timer);
  	del_timer(&self->discovery_timer);
  	del_timer(&self->final_timer);
  	del_timer(&self->poll_timer);
  	del_timer(&self->wd_timer);
  	del_timer(&self->backoff_timer);
  	del_timer(&self->media_busy_timer);
  
  	irlap_flush_all_queues(self);
  
  	self->magic = 0;
  
  	kfree(self);
  }
  
  /*
   * Function irlap_close (self)
   *
   *    Remove IrLAP instance
   *
   */
  void irlap_close(struct irlap_cb *self)
  {
  	struct irlap_cb *lap;

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* We used to send a LAP_DISC_INDICATION here, but this was
  	 * racy. This has been move within irlmp_unregister_link()
  	 * itself. Jean II */
  
  	/* Kill the LAP and all LSAPs on top of it */
  	irlmp_unregister_link(self->saddr);
  	self->notify.instance = NULL;
  
  	/* Be sure that we manage to remove ourself from the hash */
  	lap = hashbin_remove(irlap, self->saddr, NULL);
  	if (!lap) {

  		pr_debug("%s(), Didn't find myself!
  ", __func__);

  		return;
  	}
  	__irlap_close(lap);
  }
  EXPORT_SYMBOL(irlap_close);
  
  /*
   * Function irlap_connect_indication (self, skb)
   *
   *    Another device is attempting to make a connection
   *
   */
  void irlap_connect_indication(struct irlap_cb *self, struct sk_buff *skb)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	irlap_init_qos_capabilities(self, NULL); /* No user QoS! */
  
  	irlmp_link_connect_indication(self->notify.instance, self->saddr,
  				      self->daddr, &self->qos_tx, skb);
  }
  
  /*
   * Function irlap_connect_response (self, skb)
   *
   *    Service user has accepted incoming connection
   *
   */
  void irlap_connect_response(struct irlap_cb *self, struct sk_buff *userdata)
  {

  	irlap_do_event(self, CONNECT_RESPONSE, userdata, NULL);
  }
  
  /*
   * Function irlap_connect_request (self, daddr, qos_user, sniff)
   *
   *    Request connection with another device, sniffing is not implemented
   *    yet.
   *
   */
  void irlap_connect_request(struct irlap_cb *self, __u32 daddr,
  			   struct qos_info *qos_user, int sniff)
  {

  	pr_debug("%s(), daddr=0x%08x
  ", __func__, daddr);

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	self->daddr = daddr;
  
  	/*
  	 *  If the service user specifies QoS values for this connection,
  	 *  then use them
  	 */
  	irlap_init_qos_capabilities(self, qos_user);
  
  	if ((self->state == LAP_NDM) && !self->media_busy)
  		irlap_do_event(self, CONNECT_REQUEST, NULL, NULL);
  	else
  		self->connect_pending = TRUE;
  }
  
  /*
   * Function irlap_connect_confirm (self, skb)
   *
   *    Connection request has been accepted
   *
   */
  void irlap_connect_confirm(struct irlap_cb *self, struct sk_buff *skb)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	irlmp_link_connect_confirm(self->notify.instance, &self->qos_tx, skb);
  }
  
  /*
   * Function irlap_data_indication (self, skb)
   *
   *    Received data frames from IR-port, so we just pass them up to
   *    IrLMP for further processing
   *
   */
  void irlap_data_indication(struct irlap_cb *self, struct sk_buff *skb,
  			   int unreliable)
  {
  	/* Hide LAP header from IrLMP layer */
  	skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
  
  	irlmp_link_data_indication(self->notify.instance, skb, unreliable);
  }
  
  
  /*
   * Function irlap_data_request (self, skb)
   *
   *    Queue data for transmission, must wait until XMIT state
   *
   */
  void irlap_data_request(struct irlap_cb *self, struct sk_buff *skb,
  			int unreliable)
  {
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

  	IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
  		    return;);
  	skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
  
  	/*
  	 *  Must set frame format now so that the rest of the code knows
  	 *  if its dealing with an I or an UI frame
  	 */
  	if (unreliable)
  		skb->data[1] = UI_FRAME;
  	else
  		skb->data[1] = I_FRAME;
  
  	/* Don't forget to refcount it - see irlmp_connect_request(). */
  	skb_get(skb);
  
  	/* Add at the end of the queue (keep ordering) - Jean II */
  	skb_queue_tail(&self->txq, skb);
  
  	/*
  	 *  Send event if this frame only if we are in the right state
  	 *  FIXME: udata should be sent first! (skb_queue_head?)
  	 */
  	if ((self->state == LAP_XMIT_P) || (self->state == LAP_XMIT_S)) {
  		/* If we are not already processing the Tx queue, trigger
  		 * transmission immediately - Jean II */
  		if((skb_queue_len(&self->txq) <= 1) && (!self->local_busy))
  			irlap_do_event(self, DATA_REQUEST, skb, NULL);
  		/* Otherwise, the packets will be sent normally at the
  		 * next pf-poll - Jean II */
  	}
  }
  
  /*
   * Function irlap_unitdata_request (self, skb)
   *
   *    Send Ultra data. This is data that must be sent outside any connection
   *
   */
  #ifdef CONFIG_IRDA_ULTRA
  void irlap_unitdata_request(struct irlap_cb *self, struct sk_buff *skb)
  {
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

  	IRDA_ASSERT(skb_headroom(skb) >= (LAP_ADDR_HEADER+LAP_CTRL_HEADER),
  	       return;);
  	skb_push(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
  
  	skb->data[0] = CBROADCAST;
  	skb->data[1] = UI_FRAME;
  
  	/* Don't need to refcount, see irlmp_connless_data_request() */
  
  	skb_queue_tail(&self->txq_ultra, skb);
  
  	irlap_do_event(self, SEND_UI_FRAME, NULL, NULL);
  }
  #endif /*CONFIG_IRDA_ULTRA */
  
  /*
   * Function irlap_udata_indication (self, skb)
   *
   *    Receive Ultra data. This is data that is received outside any connection
   *
   */
  #ifdef CONFIG_IRDA_ULTRA
  void irlap_unitdata_indication(struct irlap_cb *self, struct sk_buff *skb)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(skb != NULL, return;);
  
  	/* Hide LAP header from IrLMP layer */
  	skb_pull(skb, LAP_ADDR_HEADER+LAP_CTRL_HEADER);
  
  	irlmp_link_unitdata_indication(self->notify.instance, skb);
  }
  #endif /* CONFIG_IRDA_ULTRA */
  
  /*
   * Function irlap_disconnect_request (void)
   *
   *    Request to disconnect connection by service user
   */
  void irlap_disconnect_request(struct irlap_cb *self)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Don't disconnect until all data frames are successfully sent */

  	if (!skb_queue_empty(&self->txq)) {

  		self->disconnect_pending = TRUE;

  		return;
  	}
  
  	/* Check if we are in the right state for disconnecting */
  	switch (self->state) {

  	case LAP_XMIT_P:        /* FALLTHROUGH */
  	case LAP_XMIT_S:        /* FALLTHROUGH */
  	case LAP_CONN:          /* FALLTHROUGH */
  	case LAP_RESET_WAIT:    /* FALLTHROUGH */

  	case LAP_RESET_CHECK:
  		irlap_do_event(self, DISCONNECT_REQUEST, NULL, NULL);
  		break;
  	default:

  		pr_debug("%s(), disconnect pending!
  ", __func__);

  		self->disconnect_pending = TRUE;
  		break;
  	}
  }
  
  /*
   * Function irlap_disconnect_indication (void)
   *
   *    Disconnect request from other device
   *
   */
  void irlap_disconnect_indication(struct irlap_cb *self, LAP_REASON reason)
  {

  	pr_debug("%s(), reason=%s
  ", __func__, lap_reasons[reason]);

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Flush queues */
  	irlap_flush_all_queues(self);
  
  	switch (reason) {
  	case LAP_RESET_INDICATION:

  		pr_debug("%s(), Sending reset request!
  ", __func__);

  		irlap_do_event(self, RESET_REQUEST, NULL, NULL);
  		break;

  	case LAP_NO_RESPONSE:	   /* FALLTHROUGH */
  	case LAP_DISC_INDICATION:  /* FALLTHROUGH */
  	case LAP_FOUND_NONE:       /* FALLTHROUGH */

  	case LAP_MEDIA_BUSY:
  		irlmp_link_disconnect_indication(self->notify.instance, self,
  						 reason, NULL);
  		break;
  	default:

  		net_err_ratelimited("%s: Unknown reason %d
  ",
  				    __func__, reason);

  	}
  }
  
  /*
   * Function irlap_discovery_request (gen_addr_bit)
   *
   *    Start one single discovery operation.
   *
   */
  void irlap_discovery_request(struct irlap_cb *self, discovery_t *discovery)
  {
  	struct irlap_info info;
  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(discovery != NULL, return;);

  	pr_debug("%s(), nslots = %d
  ", __func__, discovery->nslots);

  
  	IRDA_ASSERT((discovery->nslots == 1) || (discovery->nslots == 6) ||
  		    (discovery->nslots == 8) || (discovery->nslots == 16),
  		    return;);
  
  	/* Discovery is only possible in NDM mode */
  	if (self->state != LAP_NDM) {

  		pr_debug("%s(), discovery only possible in NDM mode
  ",
  			 __func__);

  		irlap_discovery_confirm(self, NULL);
  		/* Note : in theory, if we are not in NDM, we could postpone
  		 * the discovery like we do for connection request.
  		 * In practice, it's not worth it. If the media was busy,
  		 * it's likely next time around it won't be busy. If we are
  		 * in REPLY state, we will get passive discovery info & event.
  		 * Jean II */
  		return;
  	}
  
  	/* Check if last discovery request finished in time, or if
  	 * it was aborted due to the media busy flag. */
  	if (self->discovery_log != NULL) {
  		hashbin_delete(self->discovery_log, (FREE_FUNC) kfree);
  		self->discovery_log = NULL;
  	}
  
  	/* All operations will occur at predictable time, no need to lock */
  	self->discovery_log = hashbin_new(HB_NOLOCK);
  
  	if (self->discovery_log == NULL) {

  		net_warn_ratelimited("%s(), Unable to allocate discovery log!
  ",
  				     __func__);

  		return;
  	}
  
  	info.S = discovery->nslots; /* Number of slots */
  	info.s = 0; /* Current slot */
  
  	self->discovery_cmd = discovery;
  	info.discovery = discovery;
  
  	/* sysctl_slot_timeout bounds are checked in irsysctl.c - Jean II */
  	self->slot_timeout = sysctl_slot_timeout * HZ / 1000;
  
  	irlap_do_event(self, DISCOVERY_REQUEST, NULL, &info);
  }
  
  /*
   * Function irlap_discovery_confirm (log)
   *
   *    A device has been discovered in front of this station, we
   *    report directly to LMP.
   */
  void irlap_discovery_confirm(struct irlap_cb *self, hashbin_t *discovery_log)
  {
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	IRDA_ASSERT(self->notify.instance != NULL, return;);
  
  	/*
  	 * Check for successful discovery, since we are then allowed to clear
  	 * the media busy condition (IrLAP 6.13.4 - p.94). This should allow
  	 * us to make connection attempts much faster and easier (i.e. no
  	 * collisions).
  	 * Setting media busy to false will also generate an event allowing
  	 * to process pending events in NDM state machine.
  	 * Note : the spec doesn't define what's a successful discovery is.
  	 * If we want Ultra to work, it's successful even if there is
  	 * nobody discovered - Jean II
  	 */
  	if (discovery_log)
  		irda_device_set_media_busy(self->netdev, FALSE);
  
  	/* Inform IrLMP */
  	irlmp_link_discovery_confirm(self->notify.instance, discovery_log);
  }
  
  /*
   * Function irlap_discovery_indication (log)
   *
   *    Somebody is trying to discover us!
   *
   */
  void irlap_discovery_indication(struct irlap_cb *self, discovery_t *discovery)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(discovery != NULL, return;);
  
  	IRDA_ASSERT(self->notify.instance != NULL, return;);
  
  	/* A device is very likely to connect immediately after it performs
  	 * a successful discovery. This means that in our case, we are much
  	 * more likely to receive a connection request over the medium.
  	 * So, we backoff to avoid collisions.
  	 * IrLAP spec 6.13.4 suggest 100ms...
  	 * Note : this little trick actually make a *BIG* difference. If I set
  	 * my Linux box with discovery enabled and one Ultra frame sent every
  	 * second, my Palm has no trouble connecting to it every time !
  	 * Jean II */
  	irda_device_set_media_busy(self->netdev, SMALL);
  
  	irlmp_link_discovery_indication(self->notify.instance, discovery);
  }
  
  /*
   * Function irlap_status_indication (quality_of_link)
   */
  void irlap_status_indication(struct irlap_cb *self, int quality_of_link)
  {
  	switch (quality_of_link) {
  	case STATUS_NO_ACTIVITY:

  		net_info_ratelimited("IrLAP, no activity on link!
  ");

  		break;
  	case STATUS_NOISY:

  		net_info_ratelimited("IrLAP, noisy link!
  ");

  		break;
  	default:
  		break;
  	}
  	irlmp_status_indication(self->notify.instance,
  				quality_of_link, LOCK_NO_CHANGE);
  }
  
  /*
   * Function irlap_reset_indication (void)
   */
  void irlap_reset_indication(struct irlap_cb *self)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	if (self->state == LAP_RESET_WAIT)
  		irlap_do_event(self, RESET_REQUEST, NULL, NULL);
  	else
  		irlap_do_event(self, RESET_RESPONSE, NULL, NULL);
  }
  
  /*
   * Function irlap_reset_confirm (void)
   */
  void irlap_reset_confirm(void)
  {

  }
  
  /*
   * Function irlap_generate_rand_time_slot (S, s)
   *
   *    Generate a random time slot between s and S-1 where
   *    S = Number of slots (0 -> S-1)
   *    s = Current slot
   */
  int irlap_generate_rand_time_slot(int S, int s)
  {
  	static int rand;
  	int slot;
  
  	IRDA_ASSERT((S - s) > 0, return 0;);
  
  	rand += jiffies;
  	rand ^= (rand << 12);
  	rand ^= (rand >> 20);
  
  	slot = s + rand % (S-s);
  
  	IRDA_ASSERT((slot >= s) || (slot < S), return 0;);
  
  	return slot;
  }
  
  /*
   * Function irlap_update_nr_received (nr)
   *
   *    Remove all acknowledged frames in current window queue. This code is
   *    not intuitive and you should not try to change it. If you think it
   *    contains bugs, please mail a patch to the author instead.
   */
  void irlap_update_nr_received(struct irlap_cb *self, int nr)
  {
  	struct sk_buff *skb = NULL;
  	int count = 0;
  
  	/*

  	 * Remove all the ack-ed frames from the window queue.
  	 */

  
  	/*
  	 *  Optimize for the common case. It is most likely that the receiver
  	 *  will acknowledge all the frames we have sent! So in that case we
  	 *  delete all frames stored in window.
  	 */
  	if (nr == self->vs) {
  		while ((skb = skb_dequeue(&self->wx_list)) != NULL) {
  			dev_kfree_skb(skb);
  		}
  		/* The last acked frame is the next to send minus one */
  		self->va = nr - 1;
  	} else {
  		/* Remove all acknowledged frames in current window */
  		while ((skb_peek(&self->wx_list) != NULL) &&
  		       (((self->va+1) % 8) != nr))
  		{
  			skb = skb_dequeue(&self->wx_list);
  			dev_kfree_skb(skb);
  
  			self->va = (self->va + 1) % 8;
  			count++;
  		}
  	}
  
  	/* Advance window */
  	self->window = self->window_size - skb_queue_len(&self->wx_list);
  }
  
  /*
   * Function irlap_validate_ns_received (ns)
   *
   *    Validate the next to send (ns) field from received frame.
   */
  int irlap_validate_ns_received(struct irlap_cb *self, int ns)
  {
  	/*  ns as expected?  */
  	if (ns == self->vr)
  		return NS_EXPECTED;
  	/*
  	 *  Stations are allowed to treat invalid NS as unexpected NS
  	 *  IrLAP, Recv ... with-invalid-Ns. p. 84
  	 */
  	return NS_UNEXPECTED;
  
  	/* return NR_INVALID; */
  }
  /*
   * Function irlap_validate_nr_received (nr)
   *
   *    Validate the next to receive (nr) field from received frame.
   *
   */
  int irlap_validate_nr_received(struct irlap_cb *self, int nr)
  {
  	/*  nr as expected?  */
  	if (nr == self->vs) {

  		pr_debug("%s(), expected!
  ", __func__);

  		return NR_EXPECTED;
  	}
  
  	/*
  	 *  unexpected nr? (but within current window), first we check if the
  	 *  ns numbers of the frames in the current window wrap.
  	 */
  	if (self->va < self->vs) {
  		if ((nr >= self->va) && (nr <= self->vs))
  			return NR_UNEXPECTED;
  	} else {
  		if ((nr >= self->va) || (nr <= self->vs))
  			return NR_UNEXPECTED;
  	}
  
  	/* Invalid nr!  */
  	return NR_INVALID;
  }
  
  /*
   * Function irlap_initiate_connection_state ()
   *
   *    Initialize the connection state parameters
   *
   */
  void irlap_initiate_connection_state(struct irlap_cb *self)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Next to send and next to receive */
  	self->vs = self->vr = 0;
  
  	/* Last frame which got acked (0 - 1) % 8 */
  	self->va = 7;
  
  	self->window = 1;
  
  	self->remote_busy = FALSE;
  	self->retry_count = 0;
  }
  
  /*
   * Function irlap_wait_min_turn_around (self, qos)
   *
   *    Wait negotiated minimum turn around time, this function actually sets
   *    the number of BOS's that must be sent before the next transmitted
   *    frame in order to delay for the specified amount of time. This is
   *    done to avoid using timers, and the forbidden udelay!
   */
  void irlap_wait_min_turn_around(struct irlap_cb *self, struct qos_info *qos)
  {
  	__u32 min_turn_time;
  	__u32 speed;
  
  	/* Get QoS values.  */
  	speed = qos->baud_rate.value;
  	min_turn_time = qos->min_turn_time.value;
  
  	/* No need to calculate XBOFs for speeds over 115200 bps */
  	if (speed > 115200) {
  		self->mtt_required = min_turn_time;
  		return;
  	}
  
  	/*
  	 *  Send additional BOF's for the next frame for the requested
  	 *  min turn time, so now we must calculate how many chars (XBOF's) we
  	 *  must send for the requested time period (min turn time)
  	 */
  	self->xbofs_delay = irlap_min_turn_time_in_bytes(speed, min_turn_time);
  }
  
  /*
   * Function irlap_flush_all_queues (void)
   *
   *    Flush all queues
   *
   */
  void irlap_flush_all_queues(struct irlap_cb *self)
  {
  	struct sk_buff* skb;
  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Free transmission queue */
  	while ((skb = skb_dequeue(&self->txq)) != NULL)
  		dev_kfree_skb(skb);
  
  	while ((skb = skb_dequeue(&self->txq_ultra)) != NULL)
  		dev_kfree_skb(skb);
  
  	/* Free sliding window buffered packets */
  	while ((skb = skb_dequeue(&self->wx_list)) != NULL)
  		dev_kfree_skb(skb);
  }
  
  /*
   * Function irlap_setspeed (self, speed)
   *
   *    Change the speed of the IrDA port
   *
   */
  static void irlap_change_speed(struct irlap_cb *self, __u32 speed, int now)
  {
  	struct sk_buff *skb;

  	pr_debug("%s(), setting speed to %d
  ", __func__, speed);

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	self->speed = speed;
  
  	/* Change speed now, or just piggyback speed on frames */
  	if (now) {
  		/* Send down empty frame to trigger speed change */

  		skb = alloc_skb(0, GFP_ATOMIC);

  		if (skb)
  			irlap_queue_xmit(self, skb);

  	}
  }
  
  /*
   * Function irlap_init_qos_capabilities (self, qos)
   *
   *    Initialize QoS for this IrLAP session, What we do is to compute the
   *    intersection of the QoS capabilities for the user, driver and for
   *    IrLAP itself. Normally, IrLAP will not specify any values, but it can
   *    be used to restrict certain values.
   */
  static void irlap_init_qos_capabilities(struct irlap_cb *self,
  					struct qos_info *qos_user)
  {
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(self->netdev != NULL, return;);
  
  	/* Start out with the maximum QoS support possible */
  	irda_init_max_qos_capabilies(&self->qos_rx);
  
  	/* Apply drivers QoS capabilities */
  	irda_qos_compute_intersection(&self->qos_rx, self->qos_dev);
  
  	/*
  	 *  Check for user supplied QoS parameters. The service user is only
  	 *  allowed to supply these values. We check each parameter since the
  	 *  user may not have set all of them.
  	 */
  	if (qos_user) {

  		pr_debug("%s(), Found user specified QoS!
  ", __func__);

  
  		if (qos_user->baud_rate.bits)
  			self->qos_rx.baud_rate.bits &= qos_user->baud_rate.bits;
  
  		if (qos_user->max_turn_time.bits)
  			self->qos_rx.max_turn_time.bits &= qos_user->max_turn_time.bits;
  		if (qos_user->data_size.bits)
  			self->qos_rx.data_size.bits &= qos_user->data_size.bits;
  
  		if (qos_user->link_disc_time.bits)
  			self->qos_rx.link_disc_time.bits &= qos_user->link_disc_time.bits;
  	}
  
  	/* Use 500ms in IrLAP for now */
  	self->qos_rx.max_turn_time.bits &= 0x01;
  
  	/* Set data size */
  	/*self->qos_rx.data_size.bits &= 0x03;*/
  
  	irda_qos_bits_to_value(&self->qos_rx);
  }
  
  /*
   * Function irlap_apply_default_connection_parameters (void, now)
   *
   *    Use the default connection and transmission parameters
   */
  void irlap_apply_default_connection_parameters(struct irlap_cb *self)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* xbofs : Default value in NDM */
  	self->next_bofs   = 12;
  	self->bofs_count  = 12;
  
  	/* NDM Speed is 9600 */
  	irlap_change_speed(self, 9600, TRUE);
  
  	/* Set mbusy when going to NDM state */
  	irda_device_set_media_busy(self->netdev, TRUE);
  
  	/*
  	 * Generate random connection address for this session, which must
  	 * be 7 bits wide and different from 0x00 and 0xfe
  	 */
  	while ((self->caddr == 0x00) || (self->caddr == 0xfe)) {
  		get_random_bytes(&self->caddr, sizeof(self->caddr));
  		self->caddr &= 0xfe;
  	}
  
  	/* Use default values until connection has been negitiated */
  	self->slot_timeout = sysctl_slot_timeout;
  	self->final_timeout = FINAL_TIMEOUT;
  	self->poll_timeout = POLL_TIMEOUT;
  	self->wd_timeout = WD_TIMEOUT;
  
  	/* Set some default values */
  	self->qos_tx.baud_rate.value = 9600;
  	self->qos_rx.baud_rate.value = 9600;
  	self->qos_tx.max_turn_time.value = 0;
  	self->qos_rx.max_turn_time.value = 0;
  	self->qos_tx.min_turn_time.value = 0;
  	self->qos_rx.min_turn_time.value = 0;
  	self->qos_tx.data_size.value = 64;
  	self->qos_rx.data_size.value = 64;
  	self->qos_tx.window_size.value = 1;
  	self->qos_rx.window_size.value = 1;
  	self->qos_tx.additional_bofs.value = 12;
  	self->qos_rx.additional_bofs.value = 12;
  	self->qos_tx.link_disc_time.value = 0;
  	self->qos_rx.link_disc_time.value = 0;
  
  	irlap_flush_all_queues(self);
  
  	self->disconnect_pending = FALSE;
  	self->connect_pending = FALSE;
  }
  
  /*
   * Function irlap_apply_connection_parameters (qos, now)
   *
   *    Initialize IrLAP with the negotiated QoS values
   *
   * If 'now' is false, the speed and xbofs will be changed after the next
   * frame is sent.
   * If 'now' is true, the speed and xbofs is changed immediately
   */
  void irlap_apply_connection_parameters(struct irlap_cb *self, int now)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Set the negotiated xbofs value */
  	self->next_bofs   = self->qos_tx.additional_bofs.value;
  	if (now)
  		self->bofs_count = self->next_bofs;
  
  	/* Set the negotiated link speed (may need the new xbofs value) */
  	irlap_change_speed(self, self->qos_tx.baud_rate.value, now);
  
  	self->window_size = self->qos_tx.window_size.value;
  	self->window      = self->qos_tx.window_size.value;
  
  #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
  	/*
  	 *  Calculate how many bytes it is possible to transmit before the
  	 *  link must be turned around
  	 */
  	self->line_capacity =
  		irlap_max_line_capacity(self->qos_tx.baud_rate.value,
  					self->qos_tx.max_turn_time.value);
  	self->bytes_left = self->line_capacity;
  #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
  
  
  	/*
  	 *  Initialize timeout values, some of the rules are listed on
  	 *  page 92 in IrLAP.
  	 */
  	IRDA_ASSERT(self->qos_tx.max_turn_time.value != 0, return;);
  	IRDA_ASSERT(self->qos_rx.max_turn_time.value != 0, return;);
  	/* The poll timeout applies only to the primary station.
  	 * It defines the maximum time the primary stay in XMIT mode
  	 * before timeout and turning the link around (sending a RR).
  	 * Or, this is how much we can keep the pf bit in primary mode.
  	 * Therefore, it must be lower or equal than our *OWN* max turn around.
  	 * Jean II */
  	self->poll_timeout = self->qos_tx.max_turn_time.value * HZ / 1000;
  	/* The Final timeout applies only to the primary station.
  	 * It defines the maximum time the primary wait (mostly in RECV mode)
  	 * for an answer from the secondary station before polling it again.
  	 * Therefore, it must be greater or equal than our *PARTNER*
  	 * max turn around time - Jean II */
  	self->final_timeout = self->qos_rx.max_turn_time.value * HZ / 1000;
  	/* The Watchdog Bit timeout applies only to the secondary station.
  	 * It defines the maximum time the secondary wait (mostly in RECV mode)
  	 * for poll from the primary station before getting annoyed.
  	 * Therefore, it must be greater or equal than our *PARTNER*
  	 * max turn around time - Jean II */
  	self->wd_timeout = self->final_timeout * 2;
  
  	/*
  	 * N1 and N2 are maximum retry count for *both* the final timer
  	 * and the wd timer (with a factor 2) as defined above.
  	 * After N1 retry of a timer, we give a warning to the user.
  	 * After N2 retry, we consider the link dead and disconnect it.
  	 * Jean II
  	 */
  
  	/*
  	 *  Set N1 to 0 if Link Disconnect/Threshold Time = 3 and set it to
  	 *  3 seconds otherwise. See page 71 in IrLAP for more details.
  	 *  Actually, it's not always 3 seconds, as we allow to set
  	 *  it via sysctl... Max maxtt is 500ms, and N1 need to be multiple
  	 *  of 2, so 1 second is minimum we can allow. - Jean II
  	 */
  	if (self->qos_tx.link_disc_time.value == sysctl_warn_noreply_time)
  		/*
  		 * If we set N1 to 0, it will trigger immediately, which is
  		 * not what we want. What we really want is to disable it,
  		 * Jean II
  		 */
  		self->N1 = -2; /* Disable - Need to be multiple of 2*/
  	else
  		self->N1 = sysctl_warn_noreply_time * 1000 /
  		  self->qos_rx.max_turn_time.value;

  	pr_debug("Setting N1 = %d
  ", self->N1);

  
  	/* Set N2 to match our own disconnect time */
  	self->N2 = self->qos_tx.link_disc_time.value * 1000 /
  		self->qos_rx.max_turn_time.value;

  	pr_debug("Setting N2 = %d
  ", self->N2);

  }
  
  #ifdef CONFIG_PROC_FS
  struct irlap_iter_state {
  	int id;
  };
  
  static void *irlap_seq_start(struct seq_file *seq, loff_t *pos)
  {
  	struct irlap_iter_state *iter = seq->private;
  	struct irlap_cb *self;
  
  	/* Protect our access to the tsap list */
  	spin_lock_irq(&irlap->hb_spinlock);
  	iter->id = 0;

  	for (self = (struct irlap_cb *) hashbin_get_first(irlap);

  	     self; self = (struct irlap_cb *) hashbin_get_next(irlap)) {
  		if (iter->id == *pos)
  			break;
  		++iter->id;
  	}

  	return self;
  }
  
  static void *irlap_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	struct irlap_iter_state *iter = seq->private;
  
  	++*pos;
  	++iter->id;
  	return (void *) hashbin_get_next(irlap);
  }
  
  static void irlap_seq_stop(struct seq_file *seq, void *v)
  {
  	spin_unlock_irq(&irlap->hb_spinlock);
  }
  
  static int irlap_seq_show(struct seq_file *seq, void *v)
  {
  	const struct irlap_iter_state *iter = seq->private;
  	const struct irlap_cb *self = v;

  	IRDA_ASSERT(self->magic == LAP_MAGIC, return -EINVAL;);
  
  	seq_printf(seq, "irlap%d ", iter->id);
  	seq_printf(seq, "state: %s
  ",
  		   irlap_state[self->state]);
  
  	seq_printf(seq, "  device name: %s, ",
  		   (self->netdev) ? self->netdev->name : "bug");
  	seq_printf(seq, "hardware name: %s
  ", self->hw_name);
  
  	seq_printf(seq, "  caddr: %#02x, ", self->caddr);
  	seq_printf(seq, "saddr: %#08x, ", self->saddr);
  	seq_printf(seq, "daddr: %#08x
  ", self->daddr);
  
  	seq_printf(seq, "  win size: %d, ",
  		   self->window_size);
  	seq_printf(seq, "win: %d, ", self->window);
  #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
  	seq_printf(seq, "line capacity: %d, ",
  		   self->line_capacity);
  	seq_printf(seq, "bytes left: %d
  ", self->bytes_left);
  #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
  	seq_printf(seq, "  tx queue len: %d ",
  		   skb_queue_len(&self->txq));
  	seq_printf(seq, "win queue len: %d ",
  		   skb_queue_len(&self->wx_list));
  	seq_printf(seq, "rbusy: %s", self->remote_busy ?
  		   "TRUE" : "FALSE");
  	seq_printf(seq, " mbusy: %s
  ", self->media_busy ?
  		   "TRUE" : "FALSE");
  
  	seq_printf(seq, "  retrans: %d ", self->retry_count);
  	seq_printf(seq, "vs: %d ", self->vs);
  	seq_printf(seq, "vr: %d ", self->vr);
  	seq_printf(seq, "va: %d
  ", self->va);
  
  	seq_printf(seq, "  qos\tbps\tmaxtt\tdsize\twinsize\taddbofs\tmintt\tldisc\tcomp
  ");
  
  	seq_printf(seq, "  tx\t%d\t",
  		   self->qos_tx.baud_rate.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.max_turn_time.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.data_size.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.window_size.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.additional_bofs.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.min_turn_time.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_tx.link_disc_time.value);
  	seq_printf(seq, "
  ");
  
  	seq_printf(seq, "  rx\t%d\t",
  		   self->qos_rx.baud_rate.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_rx.max_turn_time.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_rx.data_size.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_rx.window_size.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_rx.additional_bofs.value);
  	seq_printf(seq, "%d\t",
  		   self->qos_rx.min_turn_time.value);
  	seq_printf(seq, "%d
  ",
  		   self->qos_rx.link_disc_time.value);
  
  	return 0;
  }

  static const struct seq_operations irlap_seq_ops = {

  	.start  = irlap_seq_start,
  	.next   = irlap_seq_next,
  	.stop   = irlap_seq_stop,
  	.show   = irlap_seq_show,
  };
  
  static int irlap_seq_open(struct inode *inode, struct file *file)
  {

  	if (irlap == NULL)
  		return -EINVAL;

  	return seq_open_private(file, &irlap_seq_ops,
  			sizeof(struct irlap_iter_state));

  }

  const struct file_operations irlap_seq_fops = {

  	.owner		= THIS_MODULE,
  	.open           = irlap_seq_open,
  	.read           = seq_read,
  	.llseek         = seq_lseek,
  	.release	= seq_release_private,
  };
  
  #endif /* CONFIG_PROC_FS */