Initial import

1 files changed, 1891 insertions, 0 deletions

diff --git a/net/irda/irttp.c b/net/irda/irttp.c
new file mode 100644
index 000000000..b6ab41d5b
--- /dev/null
+++ b/net/irda/irttp.c
@@ -0,0 +1,1891 @@
+/*********************************************************************
+ *
+ * Filename:      irttp.c
+ * Version:       1.2
+ * Description:   Tiny Transport Protocol (TTP) implementation
+ * Status:        Stable
+ * Author:        Dag Brattli <dagb@cs.uit.no>
+ * Created at:    Sun Aug 31 20:14:31 1997
+ * Modified at:   Wed Jan  5 11:31:27 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/init.h>
+#include <linux/fs.h>
+#include <linux/seq_file.h>
+#include <linux/slab.h>
+#include <linux/export.h>
+
+#include <asm/byteorder.h>
+#include <asm/unaligned.h>
+
+#include <net/irda/irda.h>
+#include <net/irda/irlap.h>
+#include <net/irda/irlmp.h>
+#include <net/irda/parameters.h>
+#include <net/irda/irttp.h>
+
+static struct irttp_cb *irttp;
+
+static void __irttp_close_tsap(struct tsap_cb *self);
+
+static int irttp_data_indication(void *instance, void *sap,
+				 struct sk_buff *skb);
+static int irttp_udata_indication(void *instance, void *sap,
+				  struct sk_buff *skb);
+static void irttp_disconnect_indication(void *instance, void *sap,
+					LM_REASON reason, struct sk_buff *);
+static void irttp_connect_indication(void *instance, void *sap,
+				     struct qos_info *qos, __u32 max_sdu_size,
+				     __u8 header_size, struct sk_buff *skb);
+static void irttp_connect_confirm(void *instance, void *sap,
+				  struct qos_info *qos, __u32 max_sdu_size,
+				  __u8 header_size, struct sk_buff *skb);
+static void irttp_run_tx_queue(struct tsap_cb *self);
+static void irttp_run_rx_queue(struct tsap_cb *self);
+
+static void irttp_flush_queues(struct tsap_cb *self);
+static void irttp_fragment_skb(struct tsap_cb *self, struct sk_buff *skb);
+static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self);
+static void irttp_todo_expired(unsigned long data);
+static int irttp_param_max_sdu_size(void *instance, irda_param_t *param,
+				    int get);
+
+static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow);
+static void irttp_status_indication(void *instance,
+				    LINK_STATUS link, LOCK_STATUS lock);
+
+/* Information for parsing parameters in IrTTP */
+static const pi_minor_info_t pi_minor_call_table[] = {
+	{ NULL, 0 },                                             /* 0x00 */
+	{ irttp_param_max_sdu_size, PV_INTEGER | PV_BIG_ENDIAN } /* 0x01 */
+};
+static const pi_major_info_t pi_major_call_table[] = {
+	{ pi_minor_call_table, 2 }
+};
+static pi_param_info_t param_info = { pi_major_call_table, 1, 0x0f, 4 };
+
+/************************ GLOBAL PROCEDURES ************************/
+
+/*
+ * Function irttp_init (void)
+ *
+ *    Initialize the IrTTP layer. Called by module initialization code
+ *
+ */
+int __init irttp_init(void)
+{
+	irttp = kzalloc(sizeof(struct irttp_cb), GFP_KERNEL);
+	if (irttp == NULL)
+		return -ENOMEM;
+
+	irttp->magic = TTP_MAGIC;
+
+	irttp->tsaps = hashbin_new(HB_LOCK);
+	if (!irttp->tsaps) {
+		net_err_ratelimited("%s: can't allocate IrTTP hashbin!\n",
+				    __func__);
+		kfree(irttp);
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+/*
+ * Function irttp_cleanup (void)
+ *
+ *    Called by module destruction/cleanup code
+ *
+ */
+void irttp_cleanup(void)
+{
+	/* Check for main structure */
+	IRDA_ASSERT(irttp->magic == TTP_MAGIC, return;);
+
+	/*
+	 *  Delete hashbin and close all TSAP instances in it
+	 */
+	hashbin_delete(irttp->tsaps, (FREE_FUNC) __irttp_close_tsap);
+
+	irttp->magic = 0;
+
+	/* De-allocate main structure */
+	kfree(irttp);
+
+	irttp = NULL;
+}
+
+/*************************** SUBROUTINES ***************************/
+
+/*
+ * Function irttp_start_todo_timer (self, timeout)
+ *
+ *    Start todo timer.
+ *
+ * Made it more effient and unsensitive to race conditions - Jean II
+ */
+static inline void irttp_start_todo_timer(struct tsap_cb *self, int timeout)
+{
+	/* Set new value for timer */
+	mod_timer(&self->todo_timer, jiffies + timeout);
+}
+
+/*
+ * Function irttp_todo_expired (data)
+ *
+ *    Todo timer has expired!
+ *
+ * One of the restriction of the timer is that it is run only on the timer
+ * interrupt which run every 10ms. This mean that even if you set the timer
+ * with a delay of 0, it may take up to 10ms before it's run.
+ * So, to minimise latency and keep cache fresh, we try to avoid using
+ * it as much as possible.
+ * Note : we can't use tasklets, because they can't be asynchronously
+ * killed (need user context), and we can't guarantee that here...
+ * Jean II
+ */
+static void irttp_todo_expired(unsigned long data)
+{
+	struct tsap_cb *self = (struct tsap_cb *) data;
+
+	/* Check that we still exist */
+	if (!self || self->magic != TTP_TSAP_MAGIC)
+		return;
+
+	pr_debug("%s(instance=%p)\n", __func__, self);
+
+	/* Try to make some progress, especially on Tx side - Jean II */
+	irttp_run_rx_queue(self);
+	irttp_run_tx_queue(self);
+
+	/* Check if time for disconnect */
+	if (test_bit(0, &self->disconnect_pend)) {
+		/* Check if it's possible to disconnect yet */
+		if (skb_queue_empty(&self->tx_queue)) {
+			/* Make sure disconnect is not pending anymore */
+			clear_bit(0, &self->disconnect_pend);	/* FALSE */
+
+			/* Note : self->disconnect_skb may be NULL */
+			irttp_disconnect_request(self, self->disconnect_skb,
+						 P_NORMAL);
+			self->disconnect_skb = NULL;
+		} else {
+			/* Try again later */
+			irttp_start_todo_timer(self, HZ/10);
+
+			/* No reason to try and close now */
+			return;
+		}
+	}
+
+	/* Check if it's closing time */
+	if (self->close_pend)
+		/* Finish cleanup */
+		irttp_close_tsap(self);
+}
+
+/*
+ * Function irttp_flush_queues (self)
+ *
+ *     Flushes (removes all frames) in transitt-buffer (tx_list)
+ */
+static void irttp_flush_queues(struct tsap_cb *self)
+{
+	struct sk_buff *skb;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	/* Deallocate frames waiting to be sent */
+	while ((skb = skb_dequeue(&self->tx_queue)) != NULL)
+		dev_kfree_skb(skb);
+
+	/* Deallocate received frames */
+	while ((skb = skb_dequeue(&self->rx_queue)) != NULL)
+		dev_kfree_skb(skb);
+
+	/* Deallocate received fragments */
+	while ((skb = skb_dequeue(&self->rx_fragments)) != NULL)
+		dev_kfree_skb(skb);
+}
+
+/*
+ * Function irttp_reassemble (self)
+ *
+ *    Makes a new (continuous) skb of all the fragments in the fragment
+ *    queue
+ *
+ */
+static struct sk_buff *irttp_reassemble_skb(struct tsap_cb *self)
+{
+	struct sk_buff *skb, *frag;
+	int n = 0;  /* Fragment index */
+
+	IRDA_ASSERT(self != NULL, return NULL;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return NULL;);
+
+	pr_debug("%s(), self->rx_sdu_size=%d\n", __func__,
+		 self->rx_sdu_size);
+
+	skb = dev_alloc_skb(TTP_HEADER + self->rx_sdu_size);
+	if (!skb)
+		return NULL;
+
+	/*
+	 * Need to reserve space for TTP header in case this skb needs to
+	 * be requeued in case delivery failes
+	 */
+	skb_reserve(skb, TTP_HEADER);
+	skb_put(skb, self->rx_sdu_size);
+
+	/*
+	 *  Copy all fragments to a new buffer
+	 */
+	while ((frag = skb_dequeue(&self->rx_fragments)) != NULL) {
+		skb_copy_to_linear_data_offset(skb, n, frag->data, frag->len);
+		n += frag->len;
+
+		dev_kfree_skb(frag);
+	}
+
+	pr_debug("%s(), frame len=%d, rx_sdu_size=%d, rx_max_sdu_size=%d\n",
+		 __func__, n, self->rx_sdu_size, self->rx_max_sdu_size);
+	/* Note : irttp_run_rx_queue() calculate self->rx_sdu_size
+	 * by summing the size of all fragments, so we should always
+	 * have n == self->rx_sdu_size, except in cases where we
+	 * droped the last fragment (when self->rx_sdu_size exceed
+	 * self->rx_max_sdu_size), where n < self->rx_sdu_size.
+	 * Jean II */
+	IRDA_ASSERT(n <= self->rx_sdu_size, n = self->rx_sdu_size;);
+
+	/* Set the new length */
+	skb_trim(skb, n);
+
+	self->rx_sdu_size = 0;
+
+	return skb;
+}
+
+/*
+ * Function irttp_fragment_skb (skb)
+ *
+ *    Fragments a frame and queues all the fragments for transmission
+ *
+ */
+static inline void irttp_fragment_skb(struct tsap_cb *self,
+				      struct sk_buff *skb)
+{
+	struct sk_buff *frag;
+	__u8 *frame;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+	IRDA_ASSERT(skb != NULL, return;);
+
+	/*
+	 *  Split frame into a number of segments
+	 */
+	while (skb->len > self->max_seg_size) {
+		pr_debug("%s(), fragmenting ...\n", __func__);
+
+		/* Make new segment */
+		frag = alloc_skb(self->max_seg_size+self->max_header_size,
+				 GFP_ATOMIC);
+		if (!frag)
+			return;
+
+		skb_reserve(frag, self->max_header_size);
+
+		/* Copy data from the original skb into this fragment. */
+		skb_copy_from_linear_data(skb, skb_put(frag, self->max_seg_size),
+			      self->max_seg_size);
+
+		/* Insert TTP header, with the more bit set */
+		frame = skb_push(frag, TTP_HEADER);
+		frame[0] = TTP_MORE;
+
+		/* Hide the copied data from the original skb */
+		skb_pull(skb, self->max_seg_size);
+
+		/* Queue fragment */
+		skb_queue_tail(&self->tx_queue, frag);
+	}
+	/* Queue what is left of the original skb */
+	pr_debug("%s(), queuing last segment\n", __func__);
+
+	frame = skb_push(skb, TTP_HEADER);
+	frame[0] = 0x00; /* Clear more bit */
+
+	/* Queue fragment */
+	skb_queue_tail(&self->tx_queue, skb);
+}
+
+/*
+ * Function irttp_param_max_sdu_size (self, param)
+ *
+ *    Handle the MaxSduSize parameter in the connect frames, this function
+ *    will be called both when this parameter needs to be inserted into, and
+ *    extracted from the connect frames
+ */
+static int irttp_param_max_sdu_size(void *instance, irda_param_t *param,
+				    int get)
+{
+	struct tsap_cb *self;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+
+	if (get)
+		param->pv.i = self->tx_max_sdu_size;
+	else
+		self->tx_max_sdu_size = param->pv.i;
+
+	pr_debug("%s(), MaxSduSize=%d\n", __func__, param->pv.i);
+
+	return 0;
+}
+
+/*************************** CLIENT CALLS ***************************/
+/************************** LMP CALLBACKS **************************/
+/* Everything is happily mixed up. Waiting for next clean up - Jean II */
+
+/*
+ * Initialization, that has to be done on new tsap
+ * instance allocation and on duplication
+ */
+static void irttp_init_tsap(struct tsap_cb *tsap)
+{
+	spin_lock_init(&tsap->lock);
+	init_timer(&tsap->todo_timer);
+
+	skb_queue_head_init(&tsap->rx_queue);
+	skb_queue_head_init(&tsap->tx_queue);
+	skb_queue_head_init(&tsap->rx_fragments);
+}
+
+/*
+ * Function irttp_open_tsap (stsap, notify)
+ *
+ *    Create TSAP connection endpoint,
+ */
+struct tsap_cb *irttp_open_tsap(__u8 stsap_sel, int credit, notify_t *notify)
+{
+	struct tsap_cb *self;
+	struct lsap_cb *lsap;
+	notify_t ttp_notify;
+
+	IRDA_ASSERT(irttp->magic == TTP_MAGIC, return NULL;);
+
+	/* The IrLMP spec (IrLMP 1.1 p10) says that we have the right to
+	 * use only 0x01-0x6F. Of course, we can use LSAP_ANY as well.
+	 * JeanII */
+	if ((stsap_sel != LSAP_ANY) &&
+	   ((stsap_sel < 0x01) || (stsap_sel >= 0x70))) {
+		pr_debug("%s(), invalid tsap!\n", __func__);
+		return NULL;
+	}
+
+	self = kzalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
+	if (self == NULL)
+		return NULL;
+
+	/* Initialize internal objects */
+	irttp_init_tsap(self);
+
+	/* Initialise todo timer */
+	self->todo_timer.data     = (unsigned long) self;
+	self->todo_timer.function = &irttp_todo_expired;
+
+	/* Initialize callbacks for IrLMP to use */
+	irda_notify_init(&ttp_notify);
+	ttp_notify.connect_confirm = irttp_connect_confirm;
+	ttp_notify.connect_indication = irttp_connect_indication;
+	ttp_notify.disconnect_indication = irttp_disconnect_indication;
+	ttp_notify.data_indication = irttp_data_indication;
+	ttp_notify.udata_indication = irttp_udata_indication;
+	ttp_notify.flow_indication = irttp_flow_indication;
+	if (notify->status_indication != NULL)
+		ttp_notify.status_indication = irttp_status_indication;
+	ttp_notify.instance = self;
+	strncpy(ttp_notify.name, notify->name, NOTIFY_MAX_NAME);
+
+	self->magic = TTP_TSAP_MAGIC;
+	self->connected = FALSE;
+
+	/*
+	 *  Create LSAP at IrLMP layer
+	 */
+	lsap = irlmp_open_lsap(stsap_sel, &ttp_notify, 0);
+	if (lsap == NULL) {
+		pr_debug("%s: unable to allocate LSAP!!\n", __func__);
+		__irttp_close_tsap(self);
+		return NULL;
+	}
+
+	/*
+	 *  If user specified LSAP_ANY as source TSAP selector, then IrLMP
+	 *  will replace it with whatever source selector which is free, so
+	 *  the stsap_sel we have might not be valid anymore
+	 */
+	self->stsap_sel = lsap->slsap_sel;
+	pr_debug("%s(), stsap_sel=%02x\n", __func__, self->stsap_sel);
+
+	self->notify = *notify;
+	self->lsap = lsap;
+
+	hashbin_insert(irttp->tsaps, (irda_queue_t *) self, (long) self, NULL);
+
+	if (credit > TTP_RX_MAX_CREDIT)
+		self->initial_credit = TTP_RX_MAX_CREDIT;
+	else
+		self->initial_credit = credit;
+
+	return self;
+}
+EXPORT_SYMBOL(irttp_open_tsap);
+
+/*
+ * Function irttp_close (handle)
+ *
+ *    Remove an instance of a TSAP. This function should only deal with the
+ *    deallocation of the TSAP, and resetting of the TSAPs values;
+ *
+ */
+static void __irttp_close_tsap(struct tsap_cb *self)
+{
+	/* First make sure we're connected. */
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	irttp_flush_queues(self);
+
+	del_timer(&self->todo_timer);
+
+	/* This one won't be cleaned up if we are disconnect_pend + close_pend
+	 * and we receive a disconnect_indication */
+	if (self->disconnect_skb)
+		dev_kfree_skb(self->disconnect_skb);
+
+	self->connected = FALSE;
+	self->magic = ~TTP_TSAP_MAGIC;
+
+	kfree(self);
+}
+
+/*
+ * Function irttp_close (self)
+ *
+ *    Remove TSAP from list of all TSAPs and then deallocate all resources
+ *    associated with this TSAP
+ *
+ * Note : because we *free* the tsap structure, it is the responsibility
+ * of the caller to make sure we are called only once and to deal with
+ * possible race conditions. - Jean II
+ */
+int irttp_close_tsap(struct tsap_cb *self)
+{
+	struct tsap_cb *tsap;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+
+	/* Make sure tsap has been disconnected */
+	if (self->connected) {
+		/* Check if disconnect is not pending */
+		if (!test_bit(0, &self->disconnect_pend)) {
+			net_warn_ratelimited("%s: TSAP still connected!\n",
+					     __func__);
+			irttp_disconnect_request(self, NULL, P_NORMAL);
+		}
+		self->close_pend = TRUE;
+		irttp_start_todo_timer(self, HZ/10);
+
+		return 0; /* Will be back! */
+	}
+
+	tsap = hashbin_remove(irttp->tsaps, (long) self, NULL);
+
+	IRDA_ASSERT(tsap == self, return -1;);
+
+	/* Close corresponding LSAP */
+	if (self->lsap) {
+		irlmp_close_lsap(self->lsap);
+		self->lsap = NULL;
+	}
+
+	__irttp_close_tsap(self);
+
+	return 0;
+}
+EXPORT_SYMBOL(irttp_close_tsap);
+
+/*
+ * Function irttp_udata_request (self, skb)
+ *
+ *    Send unreliable data on this TSAP
+ *
+ */
+int irttp_udata_request(struct tsap_cb *self, struct sk_buff *skb)
+{
+	int ret;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+	IRDA_ASSERT(skb != NULL, return -1;);
+
+	/* Take shortcut on zero byte packets */
+	if (skb->len == 0) {
+		ret = 0;
+		goto err;
+	}
+
+	/* Check that nothing bad happens */
+	if (!self->connected) {
+		net_warn_ratelimited("%s(), Not connected\n", __func__);
+		ret = -ENOTCONN;
+		goto err;
+	}
+
+	if (skb->len > self->max_seg_size) {
+		net_err_ratelimited("%s(), UData is too large for IrLAP!\n",
+				    __func__);
+		ret = -EMSGSIZE;
+		goto err;
+	}
+
+	irlmp_udata_request(self->lsap, skb);
+	self->stats.tx_packets++;
+
+	return 0;
+
+err:
+	dev_kfree_skb(skb);
+	return ret;
+}
+EXPORT_SYMBOL(irttp_udata_request);
+
+
+/*
+ * Function irttp_data_request (handle, skb)
+ *
+ *    Queue frame for transmission. If SAR is enabled, fragement the frame
+ *    and queue the fragments for transmission
+ */
+int irttp_data_request(struct tsap_cb *self, struct sk_buff *skb)
+{
+	__u8 *frame;
+	int ret;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+	IRDA_ASSERT(skb != NULL, return -1;);
+
+	pr_debug("%s() : queue len = %d\n", __func__,
+		 skb_queue_len(&self->tx_queue));
+
+	/* Take shortcut on zero byte packets */
+	if (skb->len == 0) {
+		ret = 0;
+		goto err;
+	}
+
+	/* Check that nothing bad happens */
+	if (!self->connected) {
+		net_warn_ratelimited("%s: Not connected\n", __func__);
+		ret = -ENOTCONN;
+		goto err;
+	}
+
+	/*
+	 *  Check if SAR is disabled, and the frame is larger than what fits
+	 *  inside an IrLAP frame
+	 */
+	if ((self->tx_max_sdu_size == 0) && (skb->len > self->max_seg_size)) {
+		net_err_ratelimited("%s: SAR disabled, and data is too large for IrLAP!\n",
+				    __func__);
+		ret = -EMSGSIZE;
+		goto err;
+	}
+
+	/*
+	 *  Check if SAR is enabled, and the frame is larger than the
+	 *  TxMaxSduSize
+	 */
+	if ((self->tx_max_sdu_size != 0) &&
+	    (self->tx_max_sdu_size != TTP_SAR_UNBOUND) &&
+	    (skb->len > self->tx_max_sdu_size)) {
+		net_err_ratelimited("%s: SAR enabled, but data is larger than TxMaxSduSize!\n",
+				    __func__);
+		ret = -EMSGSIZE;
+		goto err;
+	}
+	/*
+	 *  Check if transmit queue is full
+	 */
+	if (skb_queue_len(&self->tx_queue) >= TTP_TX_MAX_QUEUE) {
+		/*
+		 *  Give it a chance to empty itself
+		 */
+		irttp_run_tx_queue(self);
+
+		/* Drop packet. This error code should trigger the caller
+		 * to resend the data in the client code - Jean II */
+		ret = -ENOBUFS;
+		goto err;
+	}
+
+	/* Queue frame, or queue frame segments */
+	if ((self->tx_max_sdu_size == 0) || (skb->len < self->max_seg_size)) {
+		/* Queue frame */
+		IRDA_ASSERT(skb_headroom(skb) >= TTP_HEADER, return -1;);
+		frame = skb_push(skb, TTP_HEADER);
+		frame[0] = 0x00; /* Clear more bit */
+
+		skb_queue_tail(&self->tx_queue, skb);
+	} else {
+		/*
+		 *  Fragment the frame, this function will also queue the
+		 *  fragments, we don't care about the fact the transmit
+		 *  queue may be overfilled by all the segments for a little
+		 *  while
+		 */
+		irttp_fragment_skb(self, skb);
+	}
+
+	/* Check if we can accept more data from client */
+	if ((!self->tx_sdu_busy) &&
+	    (skb_queue_len(&self->tx_queue) > TTP_TX_HIGH_THRESHOLD)) {
+		/* Tx queue filling up, so stop client. */
+		if (self->notify.flow_indication) {
+			self->notify.flow_indication(self->notify.instance,
+						     self, FLOW_STOP);
+		}
+		/* self->tx_sdu_busy is the state of the client.
+		 * Update state after notifying client to avoid
+		 * race condition with irttp_flow_indication().
+		 * If the queue empty itself after our test but before
+		 * we set the flag, we will fix ourselves below in
+		 * irttp_run_tx_queue().
+		 * Jean II */
+		self->tx_sdu_busy = TRUE;
+	}
+
+	/* Try to make some progress */
+	irttp_run_tx_queue(self);
+
+	return 0;
+
+err:
+	dev_kfree_skb(skb);
+	return ret;
+}
+EXPORT_SYMBOL(irttp_data_request);
+
+/*
+ * Function irttp_run_tx_queue (self)
+ *
+ *    Transmit packets queued for transmission (if possible)
+ *
+ */
+static void irttp_run_tx_queue(struct tsap_cb *self)
+{
+	struct sk_buff *skb;
+	unsigned long flags;
+	int n;
+
+	pr_debug("%s() : send_credit = %d, queue_len = %d\n",
+		 __func__,
+		 self->send_credit, skb_queue_len(&self->tx_queue));
+
+	/* Get exclusive access to the tx queue, otherwise don't touch it */
+	if (irda_lock(&self->tx_queue_lock) == FALSE)
+		return;
+
+	/* Try to send out frames as long as we have credits
+	 * and as long as LAP is not full. If LAP is full, it will
+	 * poll us through irttp_flow_indication() - Jean II */
+	while ((self->send_credit > 0) &&
+	       (!irlmp_lap_tx_queue_full(self->lsap)) &&
+	       (skb = skb_dequeue(&self->tx_queue))) {
+		/*
+		 *  Since we can transmit and receive frames concurrently,
+		 *  the code below is a critical region and we must assure that
+		 *  nobody messes with the credits while we update them.
+		 */
+		spin_lock_irqsave(&self->lock, flags);
+
+		n = self->avail_credit;
+		self->avail_credit = 0;
+
+		/* Only room for 127 credits in frame */
+		if (n > 127) {
+			self->avail_credit = n-127;
+			n = 127;
+		}
+		self->remote_credit += n;
+		self->send_credit--;
+
+		spin_unlock_irqrestore(&self->lock, flags);
+
+		/*
+		 *  More bit must be set by the data_request() or fragment()
+		 *  functions
+		 */
+		skb->data[0] |= (n & 0x7f);
+
+		/* Detach from socket.
+		 * The current skb has a reference to the socket that sent
+		 * it (skb->sk). When we pass it to IrLMP, the skb will be
+		 * stored in in IrLAP (self->wx_list). When we are within
+		 * IrLAP, we lose the notion of socket, so we should not
+		 * have a reference to a socket. So, we drop it here.
+		 *
+		 * Why does it matter ?
+		 * When the skb is freed (kfree_skb), if it is associated
+		 * with a socket, it release buffer space on the socket
+		 * (through sock_wfree() and sock_def_write_space()).
+		 * If the socket no longer exist, we may crash. Hard.
+		 * When we close a socket, we make sure that associated packets
+		 * in IrTTP are freed. However, we have no way to cancel
+		 * the packet that we have passed to IrLAP. So, if a packet
+		 * remains in IrLAP (retry on the link or else) after we
+		 * close the socket, we are dead !
+		 * Jean II */
+		if (skb->sk != NULL) {
+			/* IrSOCK application, IrOBEX, ... */
+			skb_orphan(skb);
+		}
+			/* IrCOMM over IrTTP, IrLAN, ... */
+
+		/* Pass the skb to IrLMP - done */
+		irlmp_data_request(self->lsap, skb);
+		self->stats.tx_packets++;
+	}
+
+	/* Check if we can accept more frames from client.
+	 * We don't want to wait until the todo timer to do that, and we
+	 * can't use tasklets (grr...), so we are obliged to give control
+	 * to client. That's ok, this test will be true not too often
+	 * (max once per LAP window) and we are called from places
+	 * where we can spend a bit of time doing stuff. - Jean II */
+	if ((self->tx_sdu_busy) &&
+	    (skb_queue_len(&self->tx_queue) < TTP_TX_LOW_THRESHOLD) &&
+	    (!self->close_pend)) {
+		if (self->notify.flow_indication)
+			self->notify.flow_indication(self->notify.instance,
+						     self, FLOW_START);
+
+		/* self->tx_sdu_busy is the state of the client.
+		 * We don't really have a race here, but it's always safer
+		 * to update our state after the client - Jean II */
+		self->tx_sdu_busy = FALSE;
+	}
+
+	/* Reset lock */
+	self->tx_queue_lock = 0;
+}
+
+/*
+ * Function irttp_give_credit (self)
+ *
+ *    Send a dataless flowdata TTP-PDU and give available credit to peer
+ *    TSAP
+ */
+static inline void irttp_give_credit(struct tsap_cb *self)
+{
+	struct sk_buff *tx_skb = NULL;
+	unsigned long flags;
+	int n;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	pr_debug("%s() send=%d,avail=%d,remote=%d\n",
+		 __func__,
+		 self->send_credit, self->avail_credit, self->remote_credit);
+
+	/* Give credit to peer */
+	tx_skb = alloc_skb(TTP_MAX_HEADER, GFP_ATOMIC);
+	if (!tx_skb)
+		return;
+
+	/* Reserve space for LMP, and LAP header */
+	skb_reserve(tx_skb, LMP_MAX_HEADER);
+
+	/*
+	 *  Since we can transmit and receive frames concurrently,
+	 *  the code below is a critical region and we must assure that
+	 *  nobody messes with the credits while we update them.
+	 */
+	spin_lock_irqsave(&self->lock, flags);
+
+	n = self->avail_credit;
+	self->avail_credit = 0;
+
+	/* Only space for 127 credits in frame */
+	if (n > 127) {
+		self->avail_credit = n - 127;
+		n = 127;
+	}
+	self->remote_credit += n;
+
+	spin_unlock_irqrestore(&self->lock, flags);
+
+	skb_put(tx_skb, 1);
+	tx_skb->data[0] = (__u8) (n & 0x7f);
+
+	irlmp_data_request(self->lsap, tx_skb);
+	self->stats.tx_packets++;
+}
+
+/*
+ * Function irttp_udata_indication (instance, sap, skb)
+ *
+ *    Received some unit-data (unreliable)
+ *
+ */
+static int irttp_udata_indication(void *instance, void *sap,
+				  struct sk_buff *skb)
+{
+	struct tsap_cb *self;
+	int err;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+	IRDA_ASSERT(skb != NULL, return -1;);
+
+	self->stats.rx_packets++;
+
+	/* Just pass data to layer above */
+	if (self->notify.udata_indication) {
+		err = self->notify.udata_indication(self->notify.instance,
+						    self, skb);
+		/* Same comment as in irttp_do_data_indication() */
+		if (!err)
+			return 0;
+	}
+	/* Either no handler, or handler returns an error */
+	dev_kfree_skb(skb);
+
+	return 0;
+}
+
+/*
+ * Function irttp_data_indication (instance, sap, skb)
+ *
+ *    Receive segment from IrLMP.
+ *
+ */
+static int irttp_data_indication(void *instance, void *sap,
+				 struct sk_buff *skb)
+{
+	struct tsap_cb *self;
+	unsigned long flags;
+	int n;
+
+	self = instance;
+
+	n = skb->data[0] & 0x7f;     /* Extract the credits */
+
+	self->stats.rx_packets++;
+
+	/*  Deal with inbound credit
+	 *  Since we can transmit and receive frames concurrently,
+	 *  the code below is a critical region and we must assure that
+	 *  nobody messes with the credits while we update them.
+	 */
+	spin_lock_irqsave(&self->lock, flags);
+	self->send_credit += n;
+	if (skb->len > 1)
+		self->remote_credit--;
+	spin_unlock_irqrestore(&self->lock, flags);
+
+	/*
+	 *  Data or dataless packet? Dataless frames contains only the
+	 *  TTP_HEADER.
+	 */
+	if (skb->len > 1) {
+		/*
+		 *  We don't remove the TTP header, since we must preserve the
+		 *  more bit, so the defragment routing knows what to do
+		 */
+		skb_queue_tail(&self->rx_queue, skb);
+	} else {
+		/* Dataless flowdata TTP-PDU */
+		dev_kfree_skb(skb);
+	}
+
+
+	/* Push data to the higher layer.
+	 * We do it synchronously because running the todo timer for each
+	 * receive packet would be too much overhead and latency.
+	 * By passing control to the higher layer, we run the risk that
+	 * it may take time or grab a lock. Most often, the higher layer
+	 * will only put packet in a queue.
+	 * Anyway, packets are only dripping through the IrDA, so we can
+	 * have time before the next packet.
+	 * Further, we are run from NET_BH, so the worse that can happen is
+	 * us missing the optimal time to send back the PF bit in LAP.
+	 * Jean II */
+	irttp_run_rx_queue(self);
+
+	/* We now give credits to peer in irttp_run_rx_queue().
+	 * We need to send credit *NOW*, otherwise we are going
+	 * to miss the next Tx window. The todo timer may take
+	 * a while before it's run... - Jean II */
+
+	/*
+	 * If the peer device has given us some credits and we didn't have
+	 * anyone from before, then we need to shedule the tx queue.
+	 * We need to do that because our Tx have stopped (so we may not
+	 * get any LAP flow indication) and the user may be stopped as
+	 * well. - Jean II
+	 */
+	if (self->send_credit == n) {
+		/* Restart pushing stuff to LAP */
+		irttp_run_tx_queue(self);
+		/* Note : we don't want to schedule the todo timer
+		 * because it has horrible latency. No tasklets
+		 * because the tasklet API is broken. - Jean II */
+	}
+
+	return 0;
+}
+
+/*
+ * Function irttp_status_indication (self, reason)
+ *
+ *    Status_indication, just pass to the higher layer...
+ *
+ */
+static void irttp_status_indication(void *instance,
+				    LINK_STATUS link, LOCK_STATUS lock)
+{
+	struct tsap_cb *self;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	/* Check if client has already closed the TSAP and gone away */
+	if (self->close_pend)
+		return;
+
+	/*
+	 *  Inform service user if he has requested it
+	 */
+	if (self->notify.status_indication != NULL)
+		self->notify.status_indication(self->notify.instance,
+					       link, lock);
+	else
+		pr_debug("%s(), no handler\n", __func__);
+}
+
+/*
+ * Function irttp_flow_indication (self, reason)
+ *
+ *    Flow_indication : IrLAP tells us to send more data.
+ *
+ */
+static void irttp_flow_indication(void *instance, void *sap, LOCAL_FLOW flow)
+{
+	struct tsap_cb *self;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	pr_debug("%s(instance=%p)\n", __func__, self);
+
+	/* We are "polled" directly from LAP, and the LAP want to fill
+	 * its Tx window. We want to do our best to send it data, so that
+	 * we maximise the window. On the other hand, we want to limit the
+	 * amount of work here so that LAP doesn't hang forever waiting
+	 * for packets. - Jean II */
+
+	/* Try to send some packets. Currently, LAP calls us every time
+	 * there is one free slot, so we will send only one packet.
+	 * This allow the scheduler to do its round robin - Jean II */
+	irttp_run_tx_queue(self);
+
+	/* Note regarding the interraction with higher layer.
+	 * irttp_run_tx_queue() may call the client when its queue
+	 * start to empty, via notify.flow_indication(). Initially.
+	 * I wanted this to happen in a tasklet, to avoid client
+	 * grabbing the CPU, but we can't use tasklets safely. And timer
+	 * is definitely too slow.
+	 * This will happen only once per LAP window, and usually at
+	 * the third packet (unless window is smaller). LAP is still
+	 * doing mtt and sending first packet so it's sort of OK
+	 * to do that. Jean II */
+
+	/* If we need to send disconnect. try to do it now */
+	if (self->disconnect_pend)
+		irttp_start_todo_timer(self, 0);
+}
+
+/*
+ * Function irttp_flow_request (self, command)
+ *
+ *    This function could be used by the upper layers to tell IrTTP to stop
+ *    delivering frames if the receive queues are starting to get full, or
+ *    to tell IrTTP to start delivering frames again.
+ */
+void irttp_flow_request(struct tsap_cb *self, LOCAL_FLOW flow)
+{
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	switch (flow) {
+	case FLOW_STOP:
+		pr_debug("%s(), flow stop\n", __func__);
+		self->rx_sdu_busy = TRUE;
+		break;
+	case FLOW_START:
+		pr_debug("%s(), flow start\n", __func__);
+		self->rx_sdu_busy = FALSE;
+
+		/* Client say he can accept more data, try to free our
+		 * queues ASAP - Jean II */
+		irttp_run_rx_queue(self);
+
+		break;
+	default:
+		pr_debug("%s(), Unknown flow command!\n", __func__);
+	}
+}
+EXPORT_SYMBOL(irttp_flow_request);
+
+/*
+ * Function irttp_connect_request (self, dtsap_sel, daddr, qos)
+ *
+ *    Try to connect to remote destination TSAP selector
+ *
+ */
+int irttp_connect_request(struct tsap_cb *self, __u8 dtsap_sel,
+			  __u32 saddr, __u32 daddr,
+			  struct qos_info *qos, __u32 max_sdu_size,
+			  struct sk_buff *userdata)
+{
+	struct sk_buff *tx_skb;
+	__u8 *frame;
+	__u8 n;
+
+	pr_debug("%s(), max_sdu_size=%d\n", __func__, max_sdu_size);
+
+	IRDA_ASSERT(self != NULL, return -EBADR;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -EBADR;);
+
+	if (self->connected) {
+		if (userdata)
+			dev_kfree_skb(userdata);
+		return -EISCONN;
+	}
+
+	/* Any userdata supplied? */
+	if (userdata == NULL) {
+		tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
+				   GFP_ATOMIC);
+		if (!tx_skb)
+			return -ENOMEM;
+
+		/* Reserve space for MUX_CONTROL and LAP header */
+		skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
+	} else {
+		tx_skb = userdata;
+		/*
+		 *  Check that the client has reserved enough space for
+		 *  headers
+		 */
+		IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
+			{ dev_kfree_skb(userdata); return -1; });
+	}
+
+	/* Initialize connection parameters */
+	self->connected = FALSE;
+	self->avail_credit = 0;
+	self->rx_max_sdu_size = max_sdu_size;
+	self->rx_sdu_size = 0;
+	self->rx_sdu_busy = FALSE;
+	self->dtsap_sel = dtsap_sel;
+
+	n = self->initial_credit;
+
+	self->remote_credit = 0;
+	self->send_credit = 0;
+
+	/*
+	 *  Give away max 127 credits for now
+	 */
+	if (n > 127) {
+		self->avail_credit = n - 127;
+		n = 127;
+	}
+
+	self->remote_credit = n;
+
+	/* SAR enabled? */
+	if (max_sdu_size > 0) {
+		IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
+			{ dev_kfree_skb(tx_skb); return -1; });
+
+		/* Insert SAR parameters */
+		frame = skb_push(tx_skb, TTP_HEADER + TTP_SAR_HEADER);
+
+		frame[0] = TTP_PARAMETERS | n;
+		frame[1] = 0x04; /* Length */
+		frame[2] = 0x01; /* MaxSduSize */
+		frame[3] = 0x02; /* Value length */
+
+		put_unaligned(cpu_to_be16((__u16) max_sdu_size),
+			      (__be16 *)(frame+4));
+	} else {
+		/* Insert plain TTP header */
+		frame = skb_push(tx_skb, TTP_HEADER);
+
+		/* Insert initial credit in frame */
+		frame[0] = n & 0x7f;
+	}
+
+	/* Connect with IrLMP. No QoS parameters for now */
+	return irlmp_connect_request(self->lsap, dtsap_sel, saddr, daddr, qos,
+				     tx_skb);
+}
+EXPORT_SYMBOL(irttp_connect_request);
+
+/*
+ * Function irttp_connect_confirm (handle, qos, skb)
+ *
+ *    Service user confirms TSAP connection with peer.
+ *
+ */
+static void irttp_connect_confirm(void *instance, void *sap,
+				  struct qos_info *qos, __u32 max_seg_size,
+				  __u8 max_header_size, struct sk_buff *skb)
+{
+	struct tsap_cb *self;
+	int parameters;
+	int ret;
+	__u8 plen;
+	__u8 n;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+	IRDA_ASSERT(skb != NULL, return;);
+
+	self->max_seg_size = max_seg_size - TTP_HEADER;
+	self->max_header_size = max_header_size + TTP_HEADER;
+
+	/*
+	 *  Check if we have got some QoS parameters back! This should be the
+	 *  negotiated QoS for the link.
+	 */
+	if (qos) {
+		pr_debug("IrTTP, Negotiated BAUD_RATE: %02x\n",
+			 qos->baud_rate.bits);
+		pr_debug("IrTTP, Negotiated BAUD_RATE: %d bps.\n",
+			 qos->baud_rate.value);
+	}
+
+	n = skb->data[0] & 0x7f;
+
+	pr_debug("%s(), Initial send_credit=%d\n", __func__, n);
+
+	self->send_credit = n;
+	self->tx_max_sdu_size = 0;
+	self->connected = TRUE;
+
+	parameters = skb->data[0] & 0x80;
+
+	IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
+	skb_pull(skb, TTP_HEADER);
+
+	if (parameters) {
+		plen = skb->data[0];
+
+		ret = irda_param_extract_all(self, skb->data+1,
+					     IRDA_MIN(skb->len-1, plen),
+					     &param_info);
+
+		/* Any errors in the parameter list? */
+		if (ret < 0) {
+			net_warn_ratelimited("%s: error extracting parameters\n",
+					     __func__);
+			dev_kfree_skb(skb);
+
+			/* Do not accept this connection attempt */
+			return;
+		}
+		/* Remove parameters */
+		skb_pull(skb, IRDA_MIN(skb->len, plen+1));
+	}
+
+	pr_debug("%s() send=%d,avail=%d,remote=%d\n", __func__,
+		 self->send_credit, self->avail_credit, self->remote_credit);
+
+	pr_debug("%s(), MaxSduSize=%d\n", __func__,
+		 self->tx_max_sdu_size);
+
+	if (self->notify.connect_confirm) {
+		self->notify.connect_confirm(self->notify.instance, self, qos,
+					     self->tx_max_sdu_size,
+					     self->max_header_size, skb);
+	} else
+		dev_kfree_skb(skb);
+}
+
+/*
+ * Function irttp_connect_indication (handle, skb)
+ *
+ *    Some other device is connecting to this TSAP
+ *
+ */
+static void irttp_connect_indication(void *instance, void *sap,
+		struct qos_info *qos, __u32 max_seg_size, __u8 max_header_size,
+		struct sk_buff *skb)
+{
+	struct tsap_cb *self;
+	struct lsap_cb *lsap;
+	int parameters;
+	int ret;
+	__u8 plen;
+	__u8 n;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+	IRDA_ASSERT(skb != NULL, return;);
+
+	lsap = sap;
+
+	self->max_seg_size = max_seg_size - TTP_HEADER;
+	self->max_header_size = max_header_size+TTP_HEADER;
+
+	pr_debug("%s(), TSAP sel=%02x\n", __func__, self->stsap_sel);
+
+	/* Need to update dtsap_sel if its equal to LSAP_ANY */
+	self->dtsap_sel = lsap->dlsap_sel;
+
+	n = skb->data[0] & 0x7f;
+
+	self->send_credit = n;
+	self->tx_max_sdu_size = 0;
+
+	parameters = skb->data[0] & 0x80;
+
+	IRDA_ASSERT(skb->len >= TTP_HEADER, return;);
+	skb_pull(skb, TTP_HEADER);
+
+	if (parameters) {
+		plen = skb->data[0];
+
+		ret = irda_param_extract_all(self, skb->data+1,
+					     IRDA_MIN(skb->len-1, plen),
+					     &param_info);
+
+		/* Any errors in the parameter list? */
+		if (ret < 0) {
+			net_warn_ratelimited("%s: error extracting parameters\n",
+					     __func__);
+			dev_kfree_skb(skb);
+
+			/* Do not accept this connection attempt */
+			return;
+		}
+
+		/* Remove parameters */
+		skb_pull(skb, IRDA_MIN(skb->len, plen+1));
+	}
+
+	if (self->notify.connect_indication) {
+		self->notify.connect_indication(self->notify.instance, self,
+						qos, self->tx_max_sdu_size,
+						self->max_header_size, skb);
+	} else
+		dev_kfree_skb(skb);
+}
+
+/*
+ * Function irttp_connect_response (handle, userdata)
+ *
+ *    Service user is accepting the connection, just pass it down to
+ *    IrLMP!
+ *
+ */
+int irttp_connect_response(struct tsap_cb *self, __u32 max_sdu_size,
+			   struct sk_buff *userdata)
+{
+	struct sk_buff *tx_skb;
+	__u8 *frame;
+	int ret;
+	__u8 n;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+
+	pr_debug("%s(), Source TSAP selector=%02x\n", __func__,
+		 self->stsap_sel);
+
+	/* Any userdata supplied? */
+	if (userdata == NULL) {
+		tx_skb = alloc_skb(TTP_MAX_HEADER + TTP_SAR_HEADER,
+				   GFP_ATOMIC);
+		if (!tx_skb)
+			return -ENOMEM;
+
+		/* Reserve space for MUX_CONTROL and LAP header */
+		skb_reserve(tx_skb, TTP_MAX_HEADER + TTP_SAR_HEADER);
+	} else {
+		tx_skb = userdata;
+		/*
+		 *  Check that the client has reserved enough space for
+		 *  headers
+		 */
+		IRDA_ASSERT(skb_headroom(userdata) >= TTP_MAX_HEADER,
+			{ dev_kfree_skb(userdata); return -1; });
+	}
+
+	self->avail_credit = 0;
+	self->remote_credit = 0;
+	self->rx_max_sdu_size = max_sdu_size;
+	self->rx_sdu_size = 0;
+	self->rx_sdu_busy = FALSE;
+
+	n = self->initial_credit;
+
+	/* Frame has only space for max 127 credits (7 bits) */
+	if (n > 127) {
+		self->avail_credit = n - 127;
+		n = 127;
+	}
+
+	self->remote_credit = n;
+	self->connected = TRUE;
+
+	/* SAR enabled? */
+	if (max_sdu_size > 0) {
+		IRDA_ASSERT(skb_headroom(tx_skb) >= (TTP_MAX_HEADER + TTP_SAR_HEADER),
+			{ dev_kfree_skb(tx_skb); return -1; });
+
+		/* Insert TTP header with SAR parameters */
+		frame = skb_push(tx_skb, TTP_HEADER + TTP_SAR_HEADER);
+
+		frame[0] = TTP_PARAMETERS | n;
+		frame[1] = 0x04; /* Length */
+
+		/* irda_param_insert(self, IRTTP_MAX_SDU_SIZE, frame+1,  */
+/*				  TTP_SAR_HEADER, &param_info) */
+
+		frame[2] = 0x01; /* MaxSduSize */
+		frame[3] = 0x02; /* Value length */
+
+		put_unaligned(cpu_to_be16((__u16) max_sdu_size),
+			      (__be16 *)(frame+4));
+	} else {
+		/* Insert TTP header */
+		frame = skb_push(tx_skb, TTP_HEADER);
+
+		frame[0] = n & 0x7f;
+	}
+
+	ret = irlmp_connect_response(self->lsap, tx_skb);
+
+	return ret;
+}
+EXPORT_SYMBOL(irttp_connect_response);
+
+/*
+ * Function irttp_dup (self, instance)
+ *
+ *    Duplicate TSAP, can be used by servers to confirm a connection on a
+ *    new TSAP so it can keep listening on the old one.
+ */
+struct tsap_cb *irttp_dup(struct tsap_cb *orig, void *instance)
+{
+	struct tsap_cb *new;
+	unsigned long flags;
+
+	/* Protect our access to the old tsap instance */
+	spin_lock_irqsave(&irttp->tsaps->hb_spinlock, flags);
+
+	/* Find the old instance */
+	if (!hashbin_find(irttp->tsaps, (long) orig, NULL)) {
+		pr_debug("%s(), unable to find TSAP\n", __func__);
+		spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
+		return NULL;
+	}
+
+	/* Allocate a new instance */
+	new = kmemdup(orig, sizeof(struct tsap_cb), GFP_ATOMIC);
+	if (!new) {
+		pr_debug("%s(), unable to kmalloc\n", __func__);
+		spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
+		return NULL;
+	}
+	spin_lock_init(&new->lock);
+
+	/* We don't need the old instance any more */
+	spin_unlock_irqrestore(&irttp->tsaps->hb_spinlock, flags);
+
+	/* Try to dup the LSAP (may fail if we were too slow) */
+	new->lsap = irlmp_dup(orig->lsap, new);
+	if (!new->lsap) {
+		pr_debug("%s(), dup failed!\n", __func__);
+		kfree(new);
+		return NULL;
+	}
+
+	/* Not everything should be copied */
+	new->notify.instance = instance;
+
+	/* Initialize internal objects */
+	irttp_init_tsap(new);
+
+	/* This is locked */
+	hashbin_insert(irttp->tsaps, (irda_queue_t *) new, (long) new, NULL);
+
+	return new;
+}
+EXPORT_SYMBOL(irttp_dup);
+
+/*
+ * Function irttp_disconnect_request (self)
+ *
+ *    Close this connection please! If priority is high, the queued data
+ *    segments, if any, will be deallocated first
+ *
+ */
+int irttp_disconnect_request(struct tsap_cb *self, struct sk_buff *userdata,
+			     int priority)
+{
+	int ret;
+
+	IRDA_ASSERT(self != NULL, return -1;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return -1;);
+
+	/* Already disconnected? */
+	if (!self->connected) {
+		pr_debug("%s(), already disconnected!\n", __func__);
+		if (userdata)
+			dev_kfree_skb(userdata);
+		return -1;
+	}
+
+	/* Disconnect already pending ?
+	 * We need to use an atomic operation to prevent reentry. This
+	 * function may be called from various context, like user, timer
+	 * for following a disconnect_indication() (i.e. net_bh).
+	 * Jean II */
+	if (test_and_set_bit(0, &self->disconnect_pend)) {
+		pr_debug("%s(), disconnect already pending\n",
+			 __func__);
+		if (userdata)
+			dev_kfree_skb(userdata);
+
+		/* Try to make some progress */
+		irttp_run_tx_queue(self);
+		return -1;
+	}
+
+	/*
+	 *  Check if there is still data segments in the transmit queue
+	 */
+	if (!skb_queue_empty(&self->tx_queue)) {
+		if (priority == P_HIGH) {
+			/*
+			 *  No need to send the queued data, if we are
+			 *  disconnecting right now since the data will
+			 *  not have any usable connection to be sent on
+			 */
+			pr_debug("%s(): High priority!!()\n", __func__);
+			irttp_flush_queues(self);
+		} else if (priority == P_NORMAL) {
+			/*
+			 *  Must delay disconnect until after all data segments
+			 *  have been sent and the tx_queue is empty
+			 */
+			/* We'll reuse this one later for the disconnect */
+			self->disconnect_skb = userdata;  /* May be NULL */
+
+			irttp_run_tx_queue(self);
+
+			irttp_start_todo_timer(self, HZ/10);
+			return -1;
+		}
+	}
+	/* Note : we don't need to check if self->rx_queue is full and the
+	 * state of self->rx_sdu_busy because the disconnect response will
+	 * be sent at the LMP level (so even if the peer has its Tx queue
+	 * full of data). - Jean II */
+
+	pr_debug("%s(), Disconnecting ...\n", __func__);
+	self->connected = FALSE;
+
+	if (!userdata) {
+		struct sk_buff *tx_skb;
+		tx_skb = alloc_skb(LMP_MAX_HEADER, GFP_ATOMIC);
+		if (!tx_skb)
+			return -ENOMEM;
+
+		/*
+		 *  Reserve space for MUX and LAP header
+		 */
+		skb_reserve(tx_skb, LMP_MAX_HEADER);
+
+		userdata = tx_skb;
+	}
+	ret = irlmp_disconnect_request(self->lsap, userdata);
+
+	/* The disconnect is no longer pending */
+	clear_bit(0, &self->disconnect_pend);	/* FALSE */
+
+	return ret;
+}
+EXPORT_SYMBOL(irttp_disconnect_request);
+
+/*
+ * Function irttp_disconnect_indication (self, reason)
+ *
+ *    Disconnect indication, TSAP disconnected by peer?
+ *
+ */
+static void irttp_disconnect_indication(void *instance, void *sap,
+		LM_REASON reason, struct sk_buff *skb)
+{
+	struct tsap_cb *self;
+
+	self = instance;
+
+	IRDA_ASSERT(self != NULL, return;);
+	IRDA_ASSERT(self->magic == TTP_TSAP_MAGIC, return;);
+
+	/* Prevent higher layer to send more data */
+	self->connected = FALSE;
+
+	/* Check if client has already tried to close the TSAP */
+	if (self->close_pend) {
+		/* In this case, the higher layer is probably gone. Don't
+		 * bother it and clean up the remains - Jean II */
+		if (skb)
+			dev_kfree_skb(skb);
+		irttp_close_tsap(self);
+		return;
+	}
+
+	/* If we are here, we assume that is the higher layer is still
+	 * waiting for the disconnect notification and able to process it,
+	 * even if he tried to disconnect. Otherwise, it would have already
+	 * attempted to close the tsap and self->close_pend would be TRUE.
+	 * Jean II */
+
+	/* No need to notify the client if has already tried to disconnect */
+	if (self->notify.disconnect_indication)
+		self->notify.disconnect_indication(self->notify.instance, self,
+						   reason, skb);
+	else
+		if (skb)
+			dev_kfree_skb(skb);
+}
+
+/*
+ * Function irttp_do_data_indication (self, skb)
+ *
+ *    Try to deliver reassembled skb to layer above, and requeue it if that
+ *    for some reason should fail. We mark rx sdu as busy to apply back
+ *    pressure is necessary.
+ */
+static void irttp_do_data_indication(struct tsap_cb *self, struct sk_buff *skb)
+{
+	int err;
+
+	/* Check if client has already closed the TSAP and gone away */
+	if (self->close_pend) {
+		dev_kfree_skb(skb);
+		return;
+	}
+
+	err = self->notify.data_indication(self->notify.instance, self, skb);
+
+	/* Usually the layer above will notify that it's input queue is
+	 * starting to get filled by using the flow request, but this may
+	 * be difficult, so it can instead just refuse to eat it and just
+	 * give an error back
+	 */
+	if (err) {
+		pr_debug("%s() requeueing skb!\n", __func__);
+
+		/* Make sure we take a break */
+		self->rx_sdu_busy = TRUE;
+
+		/* Need to push the header in again */
+		skb_push(skb, TTP_HEADER);
+		skb->data[0] = 0x00; /* Make sure MORE bit is cleared */
+
+		/* Put skb back on queue */
+		skb_queue_head(&self->rx_queue, skb);
+	}
+}
+
+/*
+ * Function irttp_run_rx_queue (self)
+ *
+ *     Check if we have any frames to be transmitted, or if we have any
+ *     available credit to give away.
+ */
+static void irttp_run_rx_queue(struct tsap_cb *self)
+{
+	struct sk_buff *skb;
+	int more = 0;
+
+	pr_debug("%s() send=%d,avail=%d,remote=%d\n", __func__,
+		 self->send_credit, self->avail_credit, self->remote_credit);
+
+	/* Get exclusive access to the rx queue, otherwise don't touch it */
+	if (irda_lock(&self->rx_queue_lock) == FALSE)
+		return;
+
+	/*
+	 *  Reassemble all frames in receive queue and deliver them
+	 */
+	while (!self->rx_sdu_busy && (skb = skb_dequeue(&self->rx_queue))) {
+		/* This bit will tell us if it's the last fragment or not */
+		more = skb->data[0] & 0x80;
+
+		/* Remove TTP header */
+		skb_pull(skb, TTP_HEADER);
+
+		/* Add the length of the remaining data */
+		self->rx_sdu_size += skb->len;
+
+		/*
+		 * If SAR is disabled, or user has requested no reassembly
+		 * of received fragments then we just deliver them
+		 * immediately. This can be requested by clients that
+		 * implements byte streams without any message boundaries
+		 */
+		if (self->rx_max_sdu_size == TTP_SAR_DISABLE) {
+			irttp_do_data_indication(self, skb);
+			self->rx_sdu_size = 0;
+
+			continue;
+		}
+
+		/* Check if this is a fragment, and not the last fragment */
+		if (more) {
+			/*
+			 *  Queue the fragment if we still are within the
+			 *  limits of the maximum size of the rx_sdu
+			 */
+			if (self->rx_sdu_size <= self->rx_max_sdu_size) {
+				pr_debug("%s(), queueing frag\n",
+					 __func__);
+				skb_queue_tail(&self->rx_fragments, skb);
+			} else {
+				/* Free the part of the SDU that is too big */
+				dev_kfree_skb(skb);
+			}
+			continue;
+		}
+		/*
+		 *  This is the last fragment, so time to reassemble!
+		 */
+		if ((self->rx_sdu_size <= self->rx_max_sdu_size) ||
+		    (self->rx_max_sdu_size == TTP_SAR_UNBOUND)) {
+			/*
+			 * A little optimizing. Only queue the fragment if
+			 * there are other fragments. Since if this is the
+			 * last and only fragment, there is no need to
+			 * reassemble :-)
+			 */
+			if (!skb_queue_empty(&self->rx_fragments)) {
+				skb_queue_tail(&self->rx_fragments,
+					       skb);
+
+				skb = irttp_reassemble_skb(self);
+			}
+
+			/* Now we can deliver the reassembled skb */
+			irttp_do_data_indication(self, skb);
+		} else {
+			pr_debug("%s(), Truncated frame\n", __func__);
+
+			/* Free the part of the SDU that is too big */
+			dev_kfree_skb(skb);
+
+			/* Deliver only the valid but truncated part of SDU */
+			skb = irttp_reassemble_skb(self);
+
+			irttp_do_data_indication(self, skb);
+		}
+		self->rx_sdu_size = 0;
+	}
+
+	/*
+	 * It's not trivial to keep track of how many credits are available
+	 * by incrementing at each packet, because delivery may fail
+	 * (irttp_do_data_indication() may requeue the frame) and because
+	 * we need to take care of fragmentation.
+	 * We want the other side to send up to initial_credit packets.
+	 * We have some frames in our queues, and we have already allowed it
+	 * to send remote_credit.
+	 * No need to spinlock, write is atomic and self correcting...
+	 * Jean II
+	 */
+	self->avail_credit = (self->initial_credit -
+			      (self->remote_credit +
+			       skb_queue_len(&self->rx_queue) +
+			       skb_queue_len(&self->rx_fragments)));
+
+	/* Do we have too much credits to send to peer ? */
+	if ((self->remote_credit <= TTP_RX_MIN_CREDIT) &&
+	    (self->avail_credit > 0)) {
+		/* Send explicit credit frame */
+		irttp_give_credit(self);
+		/* Note : do *NOT* check if tx_queue is non-empty, that
+		 * will produce deadlocks. I repeat : send a credit frame
+		 * even if we have something to send in our Tx queue.
+		 * If we have credits, it means that our Tx queue is blocked.
+		 *
+		 * Let's suppose the peer can't keep up with our Tx. He will
+		 * flow control us by not sending us any credits, and we
+		 * will stop Tx and start accumulating credits here.
+		 * Up to the point where the peer will stop its Tx queue,
+		 * for lack of credits.
+		 * Let's assume the peer application is single threaded.
+		 * It will block on Tx and never consume any Rx buffer.
+		 * Deadlock. Guaranteed. - Jean II
+		 */
+	}
+
+	/* Reset lock */
+	self->rx_queue_lock = 0;
+}
+
+#ifdef CONFIG_PROC_FS
+struct irttp_iter_state {
+	int id;
+};
+
+static void *irttp_seq_start(struct seq_file *seq, loff_t *pos)
+{
+	struct irttp_iter_state *iter = seq->private;
+	struct tsap_cb *self;
+
+	/* Protect our access to the tsap list */
+	spin_lock_irq(&irttp->tsaps->hb_spinlock);
+	iter->id = 0;
+
+	for (self = (struct tsap_cb *) hashbin_get_first(irttp->tsaps);
+	     self != NULL;
+	     self = (struct tsap_cb *) hashbin_get_next(irttp->tsaps)) {
+		if (iter->id == *pos)
+			break;
+		++iter->id;
+	}
+
+	return self;
+}
+
+static void *irttp_seq_next(struct seq_file *seq, void *v, loff_t *pos)
+{
+	struct irttp_iter_state *iter = seq->private;
+
+	++*pos;
+	++iter->id;
+	return (void *) hashbin_get_next(irttp->tsaps);
+}
+
+static void irttp_seq_stop(struct seq_file *seq, void *v)
+{
+	spin_unlock_irq(&irttp->tsaps->hb_spinlock);
+}
+
+static int irttp_seq_show(struct seq_file *seq, void *v)
+{
+	const struct irttp_iter_state *iter = seq->private;
+	const struct tsap_cb *self = v;
+
+	seq_printf(seq, "TSAP %d, ", iter->id);
+	seq_printf(seq, "stsap_sel: %02x, ",
+		   self->stsap_sel);
+	seq_printf(seq, "dtsap_sel: %02x\n",
+		   self->dtsap_sel);
+	seq_printf(seq, "  connected: %s, ",
+		   self->connected ? "TRUE" : "FALSE");
+	seq_printf(seq, "avail credit: %d, ",
+		   self->avail_credit);
+	seq_printf(seq, "remote credit: %d, ",
+		   self->remote_credit);
+	seq_printf(seq, "send credit: %d\n",
+		   self->send_credit);
+	seq_printf(seq, "  tx packets: %lu, ",
+		   self->stats.tx_packets);
+	seq_printf(seq, "rx packets: %lu, ",
+		   self->stats.rx_packets);
+	seq_printf(seq, "tx_queue len: %u ",
+		   skb_queue_len(&self->tx_queue));
+	seq_printf(seq, "rx_queue len: %u\n",
+		   skb_queue_len(&self->rx_queue));
+	seq_printf(seq, "  tx_sdu_busy: %s, ",
+		   self->tx_sdu_busy ? "TRUE" : "FALSE");
+	seq_printf(seq, "rx_sdu_busy: %s\n",
+		   self->rx_sdu_busy ? "TRUE" : "FALSE");
+	seq_printf(seq, "  max_seg_size: %u, ",
+		   self->max_seg_size);
+	seq_printf(seq, "tx_max_sdu_size: %u, ",
+		   self->tx_max_sdu_size);
+	seq_printf(seq, "rx_max_sdu_size: %u\n",
+		   self->rx_max_sdu_size);
+
+	seq_printf(seq, "  Used by (%s)\n\n",
+		   self->notify.name);
+	return 0;
+}
+
+static const struct seq_operations irttp_seq_ops = {
+	.start  = irttp_seq_start,
+	.next   = irttp_seq_next,
+	.stop   = irttp_seq_stop,
+	.show   = irttp_seq_show,
+};
+
+static int irttp_seq_open(struct inode *inode, struct file *file)
+{
+	return seq_open_private(file, &irttp_seq_ops,
+			sizeof(struct irttp_iter_state));
+}
+
+const struct file_operations irttp_seq_fops = {
+	.owner		= THIS_MODULE,
+	.open           = irttp_seq_open,
+	.read           = seq_read,
+	.llseek         = seq_lseek,
+	.release	= seq_release_private,
+};
+
+#endif /* PROC_FS */