irttp.c

linux 内核源代码

	 * 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;

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

	self = (struct tsap_cb *) 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
		IRDA_DEBUG(2, "%s(), no handler\n", __FUNCTION__);
}

/*
 * 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 = (struct tsap_cb *) instance;

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

	IRDA_DEBUG(4, "%s(instance=%p)\n", __FUNCTION__, 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_DEBUG(1, "%s()\n", __FUNCTION__);

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

	switch (flow) {
	case FLOW_STOP:
		IRDA_DEBUG(1, "%s(), flow stop\n", __FUNCTION__);
		self->rx_sdu_busy = TRUE;
		break;
	case FLOW_START:
		IRDA_DEBUG(1, "%s(), flow start\n", __FUNCTION__);
		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:
		IRDA_DEBUG(1, "%s(), Unknown flow command!\n", __FUNCTION__);
	}
}
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;

	IRDA_DEBUG(4, "%s(), max_sdu_size=%d\n", __FUNCTION__, 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)
 *
 *    Sevice 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;

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

	self = (struct tsap_cb *) 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) {
		IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %02x\n",
		       qos->baud_rate.bits);
		IRDA_DEBUG(4, "IrTTP, Negotiated BAUD_RATE: %d bps.\n",
		       qos->baud_rate.value);
	}

	n = skb->data[0] & 0x7f;

	IRDA_DEBUG(4, "%s(), Initial send_credit=%d\n", __FUNCTION__, 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) {
			IRDA_WARNING("%s: error extracting parameters\n",
				     __FUNCTION__);
			dev_kfree_skb(skb);

			/* Do not accept this connection attempt */
			return;
		}
		/* Remove parameters */
		skb_pull(skb, IRDA_MIN(skb->len, plen+1));
	}

	IRDA_DEBUG(4, "%s() send=%d,avail=%d,remote=%d\n", __FUNCTION__,
	      self->send_credit, self->avail_credit, self->remote_credit);

	IRDA_DEBUG(2, "%s(), MaxSduSize=%d\n", __FUNCTION__,
		   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
 *
 */
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 = (struct tsap_cb *) instance;

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

	lsap = (struct lsap_cb *) sap;

	self->max_seg_size = max_seg_size - TTP_HEADER;
	self->max_header_size = max_header_size+TTP_HEADER;

	IRDA_DEBUG(4, "%s(), TSAP sel=%02x\n", __FUNCTION__, 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) {
			IRDA_WARNING("%s: error extracting parameters\n",
				     __FUNCTION__);
			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;);

	IRDA_DEBUG(4, "%s(), Source TSAP selector=%02x\n", __FUNCTION__,
		   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)