irttp.c

linux 内核源代码

/*********************************************************************
 *
 * Filename:      irttp.c
 * Version:       1.2
 * Description:   Tiny Transport Protocol (TTP) implementation
 * Status:        Stable
 * Author:        Dag Brattli <[e-mail]>
 * Created at:    Sun Aug 31 20:14:31 1997
 * Modified at:   Wed Jan  5 11:31:27 2000
 * Modified by:   Dag Brattli <[e-mail]>
 *
 *     Copyright (c) 1998-2000 Dag Brattli <[e-mail]>,
 *     All Rights Reserved.
 *     Copyright (c) 2000-2003 Jean Tourrilhes <[e-mail]>
 *
 *     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 <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 pi_minor_info_t pi_minor_call_table[] = {
	{ NULL, 0 },                                             /* 0x00 */
	{ irttp_param_max_sdu_size, PV_INTEGER | PV_BIG_ENDIAN } /* 0x01 */
};
static 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) {
		IRDA_ERROR("%s: can't allocate IrTTP hashbin!\n",
			   __FUNCTION__);
		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;

	IRDA_DEBUG(4, "%s(instance=%p)\n", __FUNCTION__, 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)
 */
void irttp_flush_queues(struct tsap_cb *self)
{
	struct sk_buff* skb;

	IRDA_DEBUG(4, "%s()\n", __FUNCTION__);

	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;);

	IRDA_DEBUG(2, "%s(), self->rx_sdu_size=%d\n", __FUNCTION__,
		   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);
	}

	IRDA_DEBUG(2,
		   "%s(), frame len=%d, rx_sdu_size=%d, rx_max_sdu_size=%d\n",
		   __FUNCTION__, 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_DEBUG(2, "%s()\n", __FUNCTION__);

	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) {
		IRDA_DEBUG(2, "%s(), fragmenting ...\n", __FUNCTION__);

		/* 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 */
	IRDA_DEBUG(2, "%s(), queuing last segment\n", __FUNCTION__);

	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 = (struct tsap_cb *) 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;

	IRDA_DEBUG(1, "%s(), MaxSduSize=%d\n", __FUNCTION__, 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))) {
		IRDA_DEBUG(0, "%s(), invalid tsap!\n", __FUNCTION__);
		return NULL;
	}

	self = kzalloc(sizeof(struct tsap_cb), GFP_ATOMIC);
	if (self == NULL) {
		IRDA_DEBUG(0, "%s(), unable to kmalloc!\n", __FUNCTION__);
		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) {
		IRDA_WARNING("%s: unable to allocate LSAP!!\n", __FUNCTION__);
		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;
	IRDA_DEBUG(4, "%s(), stsap_sel=%02x\n", __FUNCTION__, 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)
{