/*********************************************************************
   *
   * Filename:      irlap_frame.c
   * Version:       1.0
   * Description:   Build and transmit IrLAP frames
   * Status:        Stable
   * Author:        Dag Brattli <dagb@cs.uit.no>
   * Created at:    Tue Aug 19 10:27:26 1997
   * Modified at:   Wed Jan  5 08:59:04 2000
   * Modified by:   Dag Brattli <dagb@cs.uit.no>
   *
   *     Copyright (c) 1998-2000 Dag Brattli <dagb@cs.uit.no>,
   *     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.
   *

   *     Neither Dag Brattli nor University of Tromsø admit liability nor

   *     provide warranty for any of this software. This material is
   *     provided "AS-IS" and at no charge.
   *
   ********************************************************************/
  
  #include <linux/skbuff.h>
  #include <linux/if.h>
  #include <linux/if_ether.h>
  #include <linux/netdevice.h>
  #include <linux/irda.h>

  #include <linux/slab.h>

  
  #include <net/pkt_sched.h>
  #include <net/sock.h>
  
  #include <asm/byteorder.h>
  
  #include <net/irda/irda.h>
  #include <net/irda/irda_device.h>
  #include <net/irda/irlap.h>
  #include <net/irda/wrapper.h>
  #include <net/irda/timer.h>
  #include <net/irda/irlap_frame.h>
  #include <net/irda/qos.h>
  
  static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  			       int command);
  
  /*
   * Function irlap_insert_info (self, skb)
   *
   *    Insert minimum turnaround time and speed information into the skb. We
   *    need to do this since it's per packet relevant information. Safe to
   *    have this function inlined since it's only called from one place
   */
  static inline void irlap_insert_info(struct irlap_cb *self,
  				     struct sk_buff *skb)
  {
  	struct irda_skb_cb *cb = (struct irda_skb_cb *) skb->cb;
  
  	/*
  	 * Insert MTT (min. turn time) and speed into skb, so that the
  	 * device driver knows which settings to use
  	 */
  	cb->magic = LAP_MAGIC;
  	cb->mtt = self->mtt_required;
  	cb->next_speed = self->speed;
  
  	/* Reset */
  	self->mtt_required = 0;
  
  	/*
  	 * Delay equals negotiated BOFs count, plus the number of BOFs to
  	 * force the negotiated minimum turnaround time
  	 */
  	cb->xbofs = self->bofs_count;
  	cb->next_xbofs = self->next_bofs;
  	cb->xbofs_delay = self->xbofs_delay;
  
  	/* Reset XBOF's delay (used only for getting min turn time) */
  	self->xbofs_delay = 0;
  	/* Put the correct xbofs value for the next packet */
  	self->bofs_count = self->next_bofs;
  }
  
  /*
   * Function irlap_queue_xmit (self, skb)
   *
   *    A little wrapper for dev_queue_xmit, so we can insert some common
   *    code into it.
   */
  void irlap_queue_xmit(struct irlap_cb *self, struct sk_buff *skb)
  {
  	/* Some common init stuff */
  	skb->dev = self->netdev;

  	skb_reset_mac_header(skb);

  	skb_reset_network_header(skb);

  	skb_reset_transport_header(skb);

  	skb->protocol = htons(ETH_P_IRDA);
  	skb->priority = TC_PRIO_BESTEFFORT;
  
  	irlap_insert_info(self, skb);

  	if (unlikely(self->mode & IRDA_MODE_MONITOR)) {

  		pr_debug("%s(): %s is in monitor mode
  ", __func__,
  			 self->netdev->name);

  		dev_kfree_skb(skb);
  		return;
  	}

  	dev_queue_xmit(skb);
  }
  
  /*
   * Function irlap_send_snrm_cmd (void)
   *
   *    Transmits a connect SNRM command frame
   */
  void irlap_send_snrm_frame(struct irlap_cb *self, struct qos_info *qos)
  {
  	struct sk_buff *tx_skb;
  	struct snrm_frame *frame;
  	int ret;
  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Allocate frame */

  	tx_skb = alloc_skb(sizeof(struct snrm_frame) +
  			   IRLAP_NEGOCIATION_PARAMS_LEN,
  			   GFP_ATOMIC);

  	if (!tx_skb)
  		return;
  
  	frame = (struct snrm_frame *) skb_put(tx_skb, 2);
  
  	/* Insert connection address field */
  	if (qos)
  		frame->caddr = CMD_FRAME | CBROADCAST;
  	else
  		frame->caddr = CMD_FRAME | self->caddr;
  
  	/* Insert control field */
  	frame->control = SNRM_CMD | PF_BIT;
  
  	/*

  	 *  If we are establishing a connection then insert QoS parameters

  	 */
  	if (qos) {

  		skb_put(tx_skb, 9); /* 25 left */

  		frame->saddr = cpu_to_le32(self->saddr);
  		frame->daddr = cpu_to_le32(self->daddr);
  
  		frame->ncaddr = self->caddr;
  
  		ret = irlap_insert_qos_negotiation_params(self, tx_skb);
  		if (ret < 0) {
  			dev_kfree_skb(tx_skb);
  			return;
  		}
  	}
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_recv_snrm_cmd (skb, info)
   *
   *    Received SNRM (Set Normal Response Mode) command frame
   *
   */
  static void irlap_recv_snrm_cmd(struct irlap_cb *self, struct sk_buff *skb,
  				struct irlap_info *info)
  {
  	struct snrm_frame *frame;
  
  	if (pskb_may_pull(skb,sizeof(struct snrm_frame))) {
  		frame = (struct snrm_frame *) skb->data;
  
  		/* Copy the new connection address ignoring the C/R bit */
  		info->caddr = frame->ncaddr & 0xFE;
  
  		/* Check if the new connection address is valid */
  		if ((info->caddr == 0x00) || (info->caddr == 0xfe)) {

  			pr_debug("%s(), invalid connection address!
  ",
  				 __func__);

  			return;
  		}
  
  		/* Copy peer device address */
  		info->daddr = le32_to_cpu(frame->saddr);
  		info->saddr = le32_to_cpu(frame->daddr);
  
  		/* Only accept if addressed directly to us */
  		if (info->saddr != self->saddr) {

  			pr_debug("%s(), not addressed to us!
  ",
  				 __func__);

  			return;
  		}
  		irlap_do_event(self, RECV_SNRM_CMD, skb, info);
  	} else {
  		/* Signal that this SNRM frame does not contain and I-field */
  		irlap_do_event(self, RECV_SNRM_CMD, skb, NULL);
  	}
  }
  
  /*
   * Function irlap_send_ua_response_frame (qos)
   *
   *    Send UA (Unnumbered Acknowledgement) frame
   *
   */
  void irlap_send_ua_response_frame(struct irlap_cb *self, struct qos_info *qos)
  {
  	struct sk_buff *tx_skb;
  	struct ua_frame *frame;
  	int ret;

  	pr_debug("%s() <%ld>
  ", __func__, jiffies);

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/* Allocate frame */

  	tx_skb = alloc_skb(sizeof(struct ua_frame) +
  			   IRLAP_NEGOCIATION_PARAMS_LEN,
  			   GFP_ATOMIC);

  	if (!tx_skb)
  		return;
  
  	frame = (struct ua_frame *) skb_put(tx_skb, 10);
  
  	/* Build UA response */
  	frame->caddr = self->caddr;
  	frame->control = UA_RSP | PF_BIT;
  
  	frame->saddr = cpu_to_le32(self->saddr);
  	frame->daddr = cpu_to_le32(self->daddr);
  
  	/* Should we send QoS negotiation parameters? */
  	if (qos) {
  		ret = irlap_insert_qos_negotiation_params(self, tx_skb);
  		if (ret < 0) {
  			dev_kfree_skb(tx_skb);
  			return;
  		}
  	}
  
  	irlap_queue_xmit(self, tx_skb);
  }
  
  
  /*
   * Function irlap_send_dm_frame (void)
   *
   *    Send disconnected mode (DM) frame
   *
   */
  void irlap_send_dm_frame( struct irlap_cb *self)
  {
  	struct sk_buff *tx_skb = NULL;

  	struct dm_frame *frame;

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

  	tx_skb = alloc_skb(sizeof(struct dm_frame), GFP_ATOMIC);

  	if (!tx_skb)
  		return;

  	frame = (struct dm_frame *)skb_put(tx_skb, 2);

  
  	if (self->state == LAP_NDM)

  		frame->caddr = CBROADCAST;

  	else

  		frame->caddr = self->caddr;

  	frame->control = DM_RSP | PF_BIT;

  
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_send_disc_frame (void)
   *
   *    Send disconnect (DISC) frame
   *
   */
  void irlap_send_disc_frame(struct irlap_cb *self)
  {
  	struct sk_buff *tx_skb = NULL;

  	struct disc_frame *frame;

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

  	tx_skb = alloc_skb(sizeof(struct disc_frame), GFP_ATOMIC);

  	if (!tx_skb)
  		return;

  	frame = (struct disc_frame *)skb_put(tx_skb, 2);

  	frame->caddr = self->caddr | CMD_FRAME;
  	frame->control = DISC_CMD | PF_BIT;

  
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_send_discovery_xid_frame (S, s, command)
   *
   *    Build and transmit a XID (eXchange station IDentifier) discovery
   *    frame.
   */
  void irlap_send_discovery_xid_frame(struct irlap_cb *self, int S, __u8 s,
  				    __u8 command, discovery_t *discovery)
  {
  	struct sk_buff *tx_skb = NULL;
  	struct xid_frame *frame;
  	__u32 bcast = BROADCAST;
  	__u8 *info;

  	pr_debug("%s(), s=%d, S=%d, command=%d
  ", __func__,
  		 s, S, command);

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(discovery != NULL, return;);

  	tx_skb = alloc_skb(sizeof(struct xid_frame) + IRLAP_DISCOVERY_INFO_LEN,
  			   GFP_ATOMIC);

  	if (!tx_skb)
  		return;
  
  	skb_put(tx_skb, 14);
  	frame = (struct xid_frame *) tx_skb->data;
  
  	if (command) {
  		frame->caddr = CBROADCAST | CMD_FRAME;
  		frame->control =  XID_CMD | PF_BIT;
  	} else {
  		frame->caddr = CBROADCAST;
  		frame->control =  XID_RSP | PF_BIT;
  	}
  	frame->ident = XID_FORMAT;
  
  	frame->saddr = cpu_to_le32(self->saddr);
  
  	if (command)
  		frame->daddr = cpu_to_le32(bcast);
  	else
  		frame->daddr = cpu_to_le32(discovery->data.daddr);
  
  	switch (S) {
  	case 1:
  		frame->flags = 0x00;
  		break;
  	case 6:
  		frame->flags = 0x01;
  		break;
  	case 8:
  		frame->flags = 0x02;
  		break;
  	case 16:
  		frame->flags = 0x03;
  		break;
  	default:
  		frame->flags = 0x02;
  		break;
  	}
  
  	frame->slotnr = s;
  	frame->version = 0x00;
  
  	/*
  	 *  Provide info for final slot only in commands, and for all
  	 *  responses. Send the second byte of the hint only if the
  	 *  EXTENSION bit is set in the first byte.
  	 */
  	if (!command || (frame->slotnr == 0xff)) {
  		int len;
  
  		if (discovery->data.hints[0] & HINT_EXTENSION) {
  			info = skb_put(tx_skb, 2);
  			info[0] = discovery->data.hints[0];
  			info[1] = discovery->data.hints[1];
  		} else {
  			info = skb_put(tx_skb, 1);
  			info[0] = discovery->data.hints[0];
  		}
  		info = skb_put(tx_skb, 1);
  		info[0] = discovery->data.charset;
  
  		len = IRDA_MIN(discovery->name_len, skb_tailroom(tx_skb));
  		info = skb_put(tx_skb, len);
  		memcpy(info, discovery->data.info, len);
  	}
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_recv_discovery_xid_rsp (skb, info)
   *
   *    Received a XID discovery response
   *
   */
  static void irlap_recv_discovery_xid_rsp(struct irlap_cb *self,
  					 struct sk_buff *skb,
  					 struct irlap_info *info)
  {
  	struct xid_frame *xid;
  	discovery_t *discovery = NULL;
  	__u8 *discovery_info;
  	char *text;

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {

  		net_err_ratelimited("%s: frame too short!
  ", __func__);

  		return;
  	}

  	xid = (struct xid_frame *) skb->data;
  
  	info->daddr = le32_to_cpu(xid->saddr);
  	info->saddr = le32_to_cpu(xid->daddr);
  
  	/* Make sure frame is addressed to us */
  	if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {

  		pr_debug("%s(), frame is not addressed to us!
  ",
  			 __func__);

  		return;
  	}

  	if ((discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC)) == NULL) {

  		net_warn_ratelimited("%s: kmalloc failed!
  ", __func__);

  		return;
  	}

  
  	discovery->data.daddr = info->daddr;
  	discovery->data.saddr = self->saddr;
  	discovery->timestamp = jiffies;

  	pr_debug("%s(), daddr=%08x
  ", __func__,
  		 discovery->data.daddr);

  
  	discovery_info = skb_pull(skb, sizeof(struct xid_frame));
  
  	/* Get info returned from peer */
  	discovery->data.hints[0] = discovery_info[0];
  	if (discovery_info[0] & HINT_EXTENSION) {

  		pr_debug("EXTENSION
  ");

  		discovery->data.hints[1] = discovery_info[1];
  		discovery->data.charset = discovery_info[2];
  		text = (char *) &discovery_info[3];
  	} else {
  		discovery->data.hints[1] = 0;
  		discovery->data.charset = discovery_info[1];
  		text = (char *) &discovery_info[2];
  	}
  	/*
  	 *  Terminate info string, should be safe since this is where the
  	 *  FCS bytes resides.
  	 */
  	skb->data[skb->len] = '\0';
  	strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
  	discovery->name_len = strlen(discovery->data.info);
  
  	info->discovery = discovery;
  
  	irlap_do_event(self, RECV_DISCOVERY_XID_RSP, skb, info);
  }
  
  /*
   * Function irlap_recv_discovery_xid_cmd (skb, info)
   *
   *    Received a XID discovery command
   *
   */
  static void irlap_recv_discovery_xid_cmd(struct irlap_cb *self,
  					 struct sk_buff *skb,
  					 struct irlap_info *info)
  {
  	struct xid_frame *xid;
  	discovery_t *discovery = NULL;
  	__u8 *discovery_info;
  	char *text;
  
  	if (!pskb_may_pull(skb, sizeof(struct xid_frame))) {

  		net_err_ratelimited("%s: frame too short!
  ", __func__);

  		return;
  	}

  	xid = (struct xid_frame *) skb->data;
  
  	info->daddr = le32_to_cpu(xid->saddr);
  	info->saddr = le32_to_cpu(xid->daddr);
  
  	/* Make sure frame is addressed to us */
  	if ((info->saddr != self->saddr) && (info->saddr != BROADCAST)) {

  		pr_debug("%s(), frame is not addressed to us!
  ",
  			 __func__);

  		return;
  	}
  
  	switch (xid->flags & 0x03) {
  	case 0x00:
  		info->S = 1;
  		break;
  	case 0x01:
  		info->S = 6;
  		break;
  	case 0x02:
  		info->S = 8;
  		break;
  	case 0x03:
  		info->S = 16;
  		break;
  	default:
  		/* Error!! */
  		return;
  	}
  	info->s = xid->slotnr;
  
  	discovery_info = skb_pull(skb, sizeof(struct xid_frame));
  
  	/*
  	 *  Check if last frame
  	 */
  	if (info->s == 0xff) {
  		/* Check if things are sane at this point... */

  		if((discovery_info == NULL) ||

  		   !pskb_may_pull(skb, 3)) {

  			net_err_ratelimited("%s: discovery frame too short!
  ",
  					    __func__);

  			return;
  		}
  
  		/*
  		 *  We now have some discovery info to deliver!
  		 */

  		discovery = kzalloc(sizeof(discovery_t), GFP_ATOMIC);

  		if (!discovery)

  			return;

  
  		discovery->data.daddr = info->daddr;
  		discovery->data.saddr = self->saddr;
  		discovery->timestamp = jiffies;
  
  		discovery->data.hints[0] = discovery_info[0];
  		if (discovery_info[0] & HINT_EXTENSION) {
  			discovery->data.hints[1] = discovery_info[1];
  			discovery->data.charset = discovery_info[2];
  			text = (char *) &discovery_info[3];
  		} else {
  			discovery->data.hints[1] = 0;
  			discovery->data.charset = discovery_info[1];
  			text = (char *) &discovery_info[2];
  		}
  		/*
  		 *  Terminate string, should be safe since this is where the
  		 *  FCS bytes resides.
  		 */
  		skb->data[skb->len] = '\0';
  		strncpy(discovery->data.info, text, NICKNAME_MAX_LEN);
  		discovery->name_len = strlen(discovery->data.info);
  
  		info->discovery = discovery;
  	} else
  		info->discovery = NULL;
  
  	irlap_do_event(self, RECV_DISCOVERY_XID_CMD, skb, info);
  }
  
  /*
   * Function irlap_send_rr_frame (self, command)
   *
   *    Build and transmit RR (Receive Ready) frame. Notice that it is currently
   *    only possible to send RR frames with the poll bit set.
   */
  void irlap_send_rr_frame(struct irlap_cb *self, int command)
  {
  	struct sk_buff *tx_skb;

  	struct rr_frame *frame;

  	tx_skb = alloc_skb(sizeof(struct rr_frame), GFP_ATOMIC);

  	if (!tx_skb)
  		return;

  	frame = (struct rr_frame *)skb_put(tx_skb, 2);

  	frame->caddr = self->caddr;
  	frame->caddr |= (command) ? CMD_FRAME : 0;

  	frame->control = RR | PF_BIT | (self->vr << 5);

  
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_send_rd_frame (self)
   *
   *    Request disconnect. Used by a secondary station to request the
   *    disconnection of the link.
   */
  void irlap_send_rd_frame(struct irlap_cb *self)
  {
  	struct sk_buff *tx_skb;

  	struct rd_frame *frame;

  	tx_skb = alloc_skb(sizeof(struct rd_frame), GFP_ATOMIC);

  	if (!tx_skb)
  		return;

  	frame = (struct rd_frame *)skb_put(tx_skb, 2);

  	frame->caddr = self->caddr;

  	frame->control = RD_RSP | PF_BIT;

  
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_recv_rr_frame (skb, info)
   *
   *    Received RR (Receive Ready) frame from peer station, no harm in
   *    making it inline since its called only from one single place
   *    (irlap_driver_rcv).
   */
  static inline void irlap_recv_rr_frame(struct irlap_cb *self,
  				       struct sk_buff *skb,
  				       struct irlap_info *info, int command)
  {
  	info->nr = skb->data[1] >> 5;
  
  	/* Check if this is a command or a response frame */
  	if (command)
  		irlap_do_event(self, RECV_RR_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_RR_RSP, skb, info);
  }
  
  /*
   * Function irlap_recv_rnr_frame (self, skb, info)
   *
   *    Received RNR (Receive Not Ready) frame from peer station
   *
   */
  static void irlap_recv_rnr_frame(struct irlap_cb *self, struct sk_buff *skb,
  				 struct irlap_info *info, int command)
  {
  	info->nr = skb->data[1] >> 5;

  	pr_debug("%s(), nr=%d, %ld
  ", __func__, info->nr, jiffies);

  
  	if (command)
  		irlap_do_event(self, RECV_RNR_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_RNR_RSP, skb, info);
  }
  
  static void irlap_recv_rej_frame(struct irlap_cb *self, struct sk_buff *skb,
  				 struct irlap_info *info, int command)
  {

  	info->nr = skb->data[1] >> 5;
  
  	/* Check if this is a command or a response frame */
  	if (command)
  		irlap_do_event(self, RECV_REJ_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_REJ_RSP, skb, info);
  }
  
  static void irlap_recv_srej_frame(struct irlap_cb *self, struct sk_buff *skb,
  				  struct irlap_info *info, int command)
  {

  	info->nr = skb->data[1] >> 5;
  
  	/* Check if this is a command or a response frame */
  	if (command)
  		irlap_do_event(self, RECV_SREJ_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_SREJ_RSP, skb, info);
  }
  
  static void irlap_recv_disc_frame(struct irlap_cb *self, struct sk_buff *skb,
  				  struct irlap_info *info, int command)
  {

  	/* Check if this is a command or a response frame */
  	if (command)
  		irlap_do_event(self, RECV_DISC_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_RD_RSP, skb, info);
  }
  
  /*
   * Function irlap_recv_ua_frame (skb, frame)
   *
   *    Received UA (Unnumbered Acknowledgement) frame
   *
   */
  static inline void irlap_recv_ua_frame(struct irlap_cb *self,
  				       struct sk_buff *skb,
  				       struct irlap_info *info)
  {
  	irlap_do_event(self, RECV_UA_RSP, skb, info);
  }
  
  /*
   * Function irlap_send_data_primary(self, skb)
   *
   *    Send I-frames as the primary station but without the poll bit set
   *
   */
  void irlap_send_data_primary(struct irlap_cb *self, struct sk_buff *skb)
  {
  	struct sk_buff *tx_skb;
  
  	if (skb->data[1] == I_FRAME) {
  
  		/*
  		 *  Insert frame sequence number (Vs) in control field before
  		 *  inserting into transmit window queue.
  		 */
  		skb->data[1] = I_FRAME | (self->vs << 1);
  
  		/*
  		 *  Insert frame in store, in case of retransmissions
  		 *  Increase skb reference count, see irlap_do_event()
  		 */
  		skb_get(skb);
  		skb_queue_tail(&self->wx_list, skb);
  
  		/* Copy buffer */
  		tx_skb = skb_clone(skb, GFP_ATOMIC);
  		if (tx_skb == NULL) {
  			return;
  		}
  
  		self->vs = (self->vs + 1) % 8;
  		self->ack_required = FALSE;
  		self->window -= 1;
  
  		irlap_send_i_frame( self, tx_skb, CMD_FRAME);
  	} else {

  		pr_debug("%s(), sending unreliable frame
  ", __func__);

  		irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
  		self->window -= 1;
  	}
  }
  /*
   * Function irlap_send_data_primary_poll (self, skb)
   *
   *    Send I(nformation) frame as primary with poll bit set
   */
  void irlap_send_data_primary_poll(struct irlap_cb *self, struct sk_buff *skb)
  {
  	struct sk_buff *tx_skb;
  	int transmission_time;
  
  	/* Stop P timer */
  	del_timer(&self->poll_timer);
  
  	/* Is this reliable or unreliable data? */
  	if (skb->data[1] == I_FRAME) {
  
  		/*
  		 *  Insert frame sequence number (Vs) in control field before
  		 *  inserting into transmit window queue.
  		 */
  		skb->data[1] = I_FRAME | (self->vs << 1);
  
  		/*
  		 *  Insert frame in store, in case of retransmissions
  		 *  Increase skb reference count, see irlap_do_event()
  		 */
  		skb_get(skb);
  		skb_queue_tail(&self->wx_list, skb);
  
  		/* Copy buffer */
  		tx_skb = skb_clone(skb, GFP_ATOMIC);
  		if (tx_skb == NULL) {
  			return;
  		}
  
  		/*
  		 *  Set poll bit if necessary. We do this to the copied
  		 *  skb, since retransmitted need to set or clear the poll
  		 *  bit depending on when they are sent.
  		 */
  		tx_skb->data[1] |= PF_BIT;
  
  		self->vs = (self->vs + 1) % 8;
  		self->ack_required = FALSE;

  		irlap_next_state(self, LAP_NRM_P);

  		irlap_send_i_frame(self, tx_skb, CMD_FRAME);
  	} else {

  		pr_debug("%s(), sending unreliable frame
  ", __func__);

  
  		if (self->ack_required) {
  			irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);

  			irlap_next_state(self, LAP_NRM_P);

  			irlap_send_rr_frame(self, CMD_FRAME);
  			self->ack_required = FALSE;
  		} else {
  			skb->data[1] |= PF_BIT;

  			irlap_next_state(self, LAP_NRM_P);

  			irlap_send_ui_frame(self, skb_get(skb), self->caddr, CMD_FRAME);
  		}
  	}
  
  	/* How much time we took for transmission of all frames.
  	 * We don't know, so let assume we used the full window. Jean II */
  	transmission_time = self->final_timeout;
  
  	/* Reset parameter so that we can fill next window */
  	self->window = self->window_size;
  
  #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
  	/* Remove what we have not used. Just do a prorata of the
  	 * bytes left in window to window capacity.
  	 * See max_line_capacities[][] in qos.c for details. Jean II */
  	transmission_time -= (self->final_timeout * self->bytes_left
  			      / self->line_capacity);

  	pr_debug("%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d
  ",
  		 __func__, self->final_timeout, self->bytes_left,
  		 self->line_capacity, transmission_time);

  
  	/* We are allowed to transmit a maximum number of bytes again. */
  	self->bytes_left = self->line_capacity;
  #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
  
  	/*
  	 * The network layer has a intermediate buffer between IrLAP
  	 * and the IrDA driver which can contain 8 frames. So, even
  	 * though IrLAP is currently sending the *last* frame of the
  	 * tx-window, the driver most likely has only just started
  	 * sending the *first* frame of the same tx-window.

  	 * I.e. we are always at the very beginning of or Tx window.

  	 * Now, we are supposed to set the final timer from the end
  	 * of our tx-window to let the other peer reply. So, we need
  	 * to add extra time to compensate for the fact that we
  	 * are really at the start of tx-window, otherwise the final timer
  	 * might expire before he can answer...
  	 * Jean II
  	 */
  	irlap_start_final_timer(self, self->final_timeout + transmission_time);
  
  	/*
  	 * The clever amongst you might ask why we do this adjustement
  	 * only here, and not in all the other cases in irlap_event.c.
  	 * In all those other case, we only send a very short management
  	 * frame (few bytes), so the adjustement would be lost in the
  	 * noise...
  	 * The exception of course is irlap_resend_rejected_frame().
  	 * Jean II */
  }
  
  /*
   * Function irlap_send_data_secondary_final (self, skb)
   *
   *    Send I(nformation) frame as secondary with final bit set
   *
   */
  void irlap_send_data_secondary_final(struct irlap_cb *self,
  				     struct sk_buff *skb)
  {
  	struct sk_buff *tx_skb = NULL;
  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(skb != NULL, return;);
  
  	/* Is this reliable or unreliable data? */
  	if (skb->data[1] == I_FRAME) {
  
  		/*
  		 *  Insert frame sequence number (Vs) in control field before
  		 *  inserting into transmit window queue.
  		 */
  		skb->data[1] = I_FRAME | (self->vs << 1);
  
  		/*
  		 *  Insert frame in store, in case of retransmissions
  		 *  Increase skb reference count, see irlap_do_event()
  		 */
  		skb_get(skb);
  		skb_queue_tail(&self->wx_list, skb);
  
  		tx_skb = skb_clone(skb, GFP_ATOMIC);
  		if (tx_skb == NULL) {
  			return;
  		}
  
  		tx_skb->data[1] |= PF_BIT;
  
  		self->vs = (self->vs + 1) % 8;
  		self->ack_required = FALSE;
  
  		irlap_send_i_frame(self, tx_skb, RSP_FRAME);
  	} else {
  		if (self->ack_required) {
  			irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
  			irlap_send_rr_frame(self, RSP_FRAME);
  			self->ack_required = FALSE;
  		} else {
  			skb->data[1] |= PF_BIT;
  			irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
  		}
  	}
  
  	self->window = self->window_size;
  #ifdef CONFIG_IRDA_DYNAMIC_WINDOW
  	/* We are allowed to transmit a maximum number of bytes again. */
  	self->bytes_left = self->line_capacity;
  #endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
  
  	irlap_start_wd_timer(self, self->wd_timeout);
  }
  
  /*
   * Function irlap_send_data_secondary (self, skb)
   *
   *    Send I(nformation) frame as secondary without final bit set
   *
   */
  void irlap_send_data_secondary(struct irlap_cb *self, struct sk_buff *skb)
  {
  	struct sk_buff *tx_skb = NULL;
  
  	/* Is this reliable or unreliable data? */
  	if (skb->data[1] == I_FRAME) {
  
  		/*
  		 *  Insert frame sequence number (Vs) in control field before
  		 *  inserting into transmit window queue.
  		 */
  		skb->data[1] = I_FRAME | (self->vs << 1);
  
  		/*
  		 *  Insert frame in store, in case of retransmissions
  		 *  Increase skb reference count, see irlap_do_event()
  		 */
  		skb_get(skb);
  		skb_queue_tail(&self->wx_list, skb);
  
  		tx_skb = skb_clone(skb, GFP_ATOMIC);
  		if (tx_skb == NULL) {
  			return;
  		}
  
  		self->vs = (self->vs + 1) % 8;
  		self->ack_required = FALSE;
  		self->window -= 1;
  
  		irlap_send_i_frame(self, tx_skb, RSP_FRAME);
  	} else {
  		irlap_send_ui_frame(self, skb_get(skb), self->caddr, RSP_FRAME);
  		self->window -= 1;
  	}
  }
  
  /*
   * Function irlap_resend_rejected_frames (nr)
   *
   *    Resend frames which has not been acknowledged. Should be safe to
   *    traverse the list without locking it since this function will only be
   *    called from interrupt context (BH)
   */
  void irlap_resend_rejected_frames(struct irlap_cb *self, int command)
  {
  	struct sk_buff *tx_skb;
  	struct sk_buff *skb;

  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);

  	/*  Resend unacknowledged frame(s) */

  	skb_queue_walk(&self->wx_list, skb) {

  		irlap_wait_min_turn_around(self, &self->qos_tx);
  
  		/* We copy the skb to be retransmitted since we will have to
  		 * modify it. Cloning will confuse packet sniffers
  		 */
  		/* tx_skb = skb_clone( skb, GFP_ATOMIC); */
  		tx_skb = skb_copy(skb, GFP_ATOMIC);
  		if (!tx_skb) {

  			pr_debug("%s(), unable to copy
  ", __func__);

  			return;
  		}

  
  		/* Clear old Nr field + poll bit */
  		tx_skb->data[1] &= 0x0f;
  
  		/*
  		 *  Set poll bit on the last frame retransmitted
  		 */

  		if (skb_queue_is_last(&self->wx_list, skb))

  			tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
  		else
  			tx_skb->data[1] &= ~PF_BIT; /* Clear p/f bit */
  
  		irlap_send_i_frame(self, tx_skb, command);

  	}
  #if 0 /* Not yet */
  	/*
  	 *  We can now fill the window with additional data frames
  	 */

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

  		pr_debug("%s(), sending additional frames!
  ", __func__);

  		if (self->window > 0) {

  			skb = skb_dequeue( &self->txq);
  			IRDA_ASSERT(skb != NULL, return;);
  
  			/*
  			 *  If send window > 1 then send frame with pf
  			 *  bit cleared
  			 */
  			if ((self->window > 1) &&

  			    !skb_queue_empty(&self->txq)) {

  				irlap_send_data_primary(self, skb);
  			} else {
  				irlap_send_data_primary_poll(self, skb);
  			}
  			kfree_skb(skb);
  		}
  	}
  #endif
  }
  
  void irlap_resend_rejected_frame(struct irlap_cb *self, int command)
  {
  	struct sk_buff *tx_skb;
  	struct sk_buff *skb;
  
  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  
  	/*  Resend unacknowledged frame(s) */
  	skb = skb_peek(&self->wx_list);
  	if (skb != NULL) {
  		irlap_wait_min_turn_around(self, &self->qos_tx);
  
  		/* We copy the skb to be retransmitted since we will have to
  		 * modify it. Cloning will confuse packet sniffers
  		 */
  		/* tx_skb = skb_clone( skb, GFP_ATOMIC); */
  		tx_skb = skb_copy(skb, GFP_ATOMIC);
  		if (!tx_skb) {

  			pr_debug("%s(), unable to copy
  ", __func__);

  			return;
  		}

  
  		/* Clear old Nr field + poll bit */
  		tx_skb->data[1] &= 0x0f;
  
  		/*  Set poll/final bit */
  		tx_skb->data[1] |= PF_BIT; /* Set p/f bit */
  
  		irlap_send_i_frame(self, tx_skb, command);
  	}
  }
  
  /*
   * Function irlap_send_ui_frame (self, skb, command)
   *
   *    Contruct and transmit an Unnumbered Information (UI) frame
   *
   */
  void irlap_send_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
  			 __u8 caddr, int command)
  {

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(skb != NULL, return;);
  
  	/* Insert connection address */
  	skb->data[0] = caddr | ((command) ? CMD_FRAME : 0);
  
  	irlap_queue_xmit(self, skb);
  }
  
  /*
   * Function irlap_send_i_frame (skb)
   *
   *    Contruct and transmit Information (I) frame
   */
  static void irlap_send_i_frame(struct irlap_cb *self, struct sk_buff *skb,
  			       int command)
  {
  	/* Insert connection address */
  	skb->data[0] = self->caddr;
  	skb->data[0] |= (command) ? CMD_FRAME : 0;
  
  	/* Insert next to receive (Vr) */
  	skb->data[1] |= (self->vr << 5);  /* insert nr */
  
  	irlap_queue_xmit(self, skb);
  }
  
  /*
   * Function irlap_recv_i_frame (skb, frame)
   *
   *    Receive and parse an I (Information) frame, no harm in making it inline
   *    since it's called only from one single place (irlap_driver_rcv).
   */
  static inline void irlap_recv_i_frame(struct irlap_cb *self,
  				      struct sk_buff *skb,
  				      struct irlap_info *info, int command)
  {
  	info->nr = skb->data[1] >> 5;          /* Next to receive */
  	info->pf = skb->data[1] & PF_BIT;      /* Final bit */
  	info->ns = (skb->data[1] >> 1) & 0x07; /* Next to send */
  
  	/* Check if this is a command or a response frame */
  	if (command)
  		irlap_do_event(self, RECV_I_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_I_RSP, skb, info);
  }
  
  /*
   * Function irlap_recv_ui_frame (self, skb, info)
   *
   *    Receive and parse an Unnumbered Information (UI) frame
   *
   */
  static void irlap_recv_ui_frame(struct irlap_cb *self, struct sk_buff *skb,
  				struct irlap_info *info)
  {

  	info->pf = skb->data[1] & PF_BIT;      /* Final bit */
  
  	irlap_do_event(self, RECV_UI_FRAME, skb, info);
  }
  
  /*
   * Function irlap_recv_frmr_frame (skb, frame)
   *
   *    Received Frame Reject response.
   *
   */
  static void irlap_recv_frmr_frame(struct irlap_cb *self, struct sk_buff *skb,
  				  struct irlap_info *info)
  {
  	__u8 *frame;
  	int w, x, y, z;

  	IRDA_ASSERT(self != NULL, return;);
  	IRDA_ASSERT(self->magic == LAP_MAGIC, return;);
  	IRDA_ASSERT(skb != NULL, return;);
  	IRDA_ASSERT(info != NULL, return;);
  
  	if (!pskb_may_pull(skb, 4)) {

  		net_err_ratelimited("%s: frame too short!
  ", __func__);

  		return;
  	}
  
  	frame = skb->data;
  
  	info->nr = frame[2] >> 5;          /* Next to receive */
  	info->pf = frame[2] & PF_BIT;      /* Final bit */
  	info->ns = (frame[2] >> 1) & 0x07; /* Next to send */
  
  	w = frame[3] & 0x01;
  	x = frame[3] & 0x02;
  	y = frame[3] & 0x04;
  	z = frame[3] & 0x08;
  
  	if (w) {

  		pr_debug("Rejected control field is undefined or not implemented
  ");

  	}
  	if (x) {

  		pr_debug("Rejected control field was invalid because it contained a non permitted I field
  ");

  	}
  	if (y) {

  		pr_debug("Received I field exceeded the maximum negotiated for the existing connection or exceeded the maximum this station supports if no connection exists
  ");

  	}
  	if (z) {

  		pr_debug("Rejected control field control field contained an invalid Nr count
  ");

  	}
  	irlap_do_event(self, RECV_FRMR_RSP, skb, info);
  }
  
  /*
   * Function irlap_send_test_frame (self, daddr)
   *
   *    Send a test frame response
   *
   */
  void irlap_send_test_frame(struct irlap_cb *self, __u8 caddr, __u32 daddr,
  			   struct sk_buff *cmd)
  {
  	struct sk_buff *tx_skb;
  	struct test_frame *frame;
  	__u8 *info;

  	tx_skb = alloc_skb(cmd->len + sizeof(struct test_frame), GFP_ATOMIC);

  	if (!tx_skb)
  		return;
  
  	/* Broadcast frames must include saddr and daddr fields */
  	if (caddr == CBROADCAST) {
  		frame = (struct test_frame *)
  			skb_put(tx_skb, sizeof(struct test_frame));
  
  		/* Insert the swapped addresses */
  		frame->saddr = cpu_to_le32(self->saddr);
  		frame->daddr = cpu_to_le32(daddr);
  	} else
  		frame = (struct test_frame *) skb_put(tx_skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);
  
  	frame->caddr = caddr;
  	frame->control = TEST_RSP | PF_BIT;
  
  	/* Copy info */
  	info = skb_put(tx_skb, cmd->len);
  	memcpy(info, cmd->data, cmd->len);
  
  	/* Return to sender */
  	irlap_wait_min_turn_around(self, &self->qos_tx);
  	irlap_queue_xmit(self, tx_skb);
  }
  
  /*
   * Function irlap_recv_test_frame (self, skb)
   *
   *    Receive a test frame
   *
   */
  static void irlap_recv_test_frame(struct irlap_cb *self, struct sk_buff *skb,
  				  struct irlap_info *info, int command)
  {
  	struct test_frame *frame;

  	if (!pskb_may_pull(skb, sizeof(*frame))) {

  		net_err_ratelimited("%s: frame too short!
  ", __func__);

  		return;
  	}
  	frame = (struct test_frame *) skb->data;
  
  	/* Broadcast frames must carry saddr and daddr fields */
  	if (info->caddr == CBROADCAST) {
  		if (skb->len < sizeof(struct test_frame)) {

  			pr_debug("%s() test frame too short!
  ",
  				 __func__);

  			return;
  		}
  
  		/* Read and swap addresses */
  		info->daddr = le32_to_cpu(frame->saddr);
  		info->saddr = le32_to_cpu(frame->daddr);
  
  		/* Make sure frame is addressed to us */
  		if ((info->saddr != self->saddr) &&
  		    (info->saddr != BROADCAST)) {
  			return;
  		}
  	}
  
  	if (command)
  		irlap_do_event(self, RECV_TEST_CMD, skb, info);
  	else
  		irlap_do_event(self, RECV_TEST_RSP, skb, info);
  }
  
  /*
   * Function irlap_driver_rcv (skb, netdev, ptype)
   *
   *    Called when a frame is received. Dispatches the right receive function
   *    for processing of the frame.
   *
   * Note on skb management :
   * After calling the higher layers of the IrDA stack, we always
   * kfree() the skb, which drop the reference count (and potentially
   * destroy it).
   * If a higher layer of the stack want to keep the skb around (to put
   * in a queue or pass it to the higher layer), it will need to use
   * skb_get() to keep a reference on it. This is usually done at the
   * LMP level in irlmp.c.
   * Jean II
   */
  int irlap_driver_rcv(struct sk_buff *skb, struct net_device *dev,

  		     struct packet_type *ptype, struct net_device *orig_dev)

  {
  	struct irlap_info info;
  	struct irlap_cb *self;
  	int command;
  	__u8 control;

  	int ret = -1;

  	if (!net_eq(dev_net(dev), &init_net))

  		goto out;

  	/* FIXME: should we get our own field? */
  	self = (struct irlap_cb *) dev->atalk_ptr;
  
  	/* If the net device is down, then IrLAP is gone! */

  	if (!self || self->magic != LAP_MAGIC)
  		goto err;

  
  	/* We are no longer an "old" protocol, so we need to handle
  	 * share and non linear skbs. This should never happen, so
  	 * we don't need to be clever about it. Jean II */
  	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) {

  		net_err_ratelimited("%s: can't clone shared skb!
  ", __func__);

  		goto err;

  	}
  
  	/* Check if frame is large enough for parsing */
  	if (!pskb_may_pull(skb, 2)) {

  		net_err_ratelimited("%s: frame too short!
  ", __func__);

  		goto err;

  	}
  
  	command    = skb->data[0] & CMD_FRAME;
  	info.caddr = skb->data[0] & CBROADCAST;
  
  	info.pf      = skb->data[1] &  PF_BIT;
  	info.control = skb->data[1] & ~PF_BIT; /* Mask away poll/final bit */
  
  	control = info.control;
  
  	/*  First we check if this frame has a valid connection address */
  	if ((info.caddr != self->caddr) && (info.caddr != CBROADCAST)) {

  		pr_debug("%s(), wrong connection address!
  ",
  			 __func__);

  		goto out;
  	}
  	/*
  	 *  Optimize for the common case and check if the frame is an
  	 *  I(nformation) frame. Only I-frames have bit 0 set to 0
  	 */
  	if (~control & 0x01) {
  		irlap_recv_i_frame(self, skb, &info, command);
  		goto out;
  	}
  	/*
  	 *  We now check is the frame is an S(upervisory) frame. Only
  	 *  S-frames have bit 0 set to 1 and bit 1 set to 0
  	 */
  	if (~control & 0x02) {
  		/*
  		 *  Received S(upervisory) frame, check which frame type it is
  		 *  only the first nibble is of interest
  		 */
  		switch (control & 0x0f) {
  		case RR:
  			irlap_recv_rr_frame(self, skb, &info, command);
  			break;
  		case RNR:
  			irlap_recv_rnr_frame(self, skb, &info, command);
  			break;
  		case REJ:
  			irlap_recv_rej_frame(self, skb, &info, command);
  			break;
  		case SREJ:
  			irlap_recv_srej_frame(self, skb, &info, command);
  			break;
  		default:

  			net_warn_ratelimited("%s: Unknown S-frame %02x received!
  ",
  					     __func__, info.control);

  			break;
  		}
  		goto out;
  	}
  	/*
  	 *  This must be a C(ontrol) frame
  	 */
  	switch (control) {
  	case XID_RSP:
  		irlap_recv_discovery_xid_rsp(self, skb, &info);
  		break;
  	case XID_CMD:
  		irlap_recv_discovery_xid_cmd(self, skb, &info);
  		break;
  	case SNRM_CMD:
  		irlap_recv_snrm_cmd(self, skb, &info);
  		break;
  	case DM_RSP:
  		irlap_do_event(self, RECV_DM_RSP, skb, &info);
  		break;
  	case DISC_CMD: /* And RD_RSP since they have the same value */
  		irlap_recv_disc_frame(self, skb, &info, command);
  		break;
  	case TEST_CMD:
  		irlap_recv_test_frame(self, skb, &info, command);
  		break;
  	case UA_RSP:
  		irlap_recv_ua_frame(self, skb, &info);
  		break;
  	case FRMR_RSP:
  		irlap_recv_frmr_frame(self, skb, &info);
  		break;
  	case UI_FRAME:
  		irlap_recv_ui_frame(self, skb, &info);
  		break;
  	default:

  		net_warn_ratelimited("%s: Unknown frame %02x received!
  ",
  				     __func__, info.control);

  		break;
  	}
  out:

  	ret = 0;
  err:

  	/* Always drop our reference on the skb */
  	dev_kfree_skb(skb);

  	return ret;

  }