irlap_frame.c

linux 内核源代码

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))) {
		IRDA_ERROR("%s: frame too short!\n", __FUNCTION__);
		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)) {
		IRDA_DEBUG(0, "%s(), frame is not addressed to us!\n",
			   __FUNCTION__);
		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)) {
			IRDA_ERROR("%s: discovery frame too short!\n",
				   __FUNCTION__);
			return;
		}

		/*
		 *  We now have some discovery info to deliver!
		 */
		discovery = kmalloc(sizeof(discovery_t), GFP_ATOMIC);
		if (!discovery) {
			IRDA_WARNING("%s: unable to malloc!\n", __FUNCTION__);
			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->caddr = 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;

	IRDA_DEBUG(4, "%s(), nr=%d, %ld\n", __FUNCTION__, 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)
{
	IRDA_DEBUG(0, "%s()\n", __FUNCTION__);

	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)
{
	IRDA_DEBUG(0, "%s()\n", __FUNCTION__);

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

	/* 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 {
		IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);
		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 {
		IRDA_DEBUG(4, "%s(), sending unreliable frame\n", __FUNCTION__);

		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);
	IRDA_DEBUG(4, "%s() adjusting transmission_time : ft=%d, bl=%d, lc=%d -> tt=%d\n", __FUNCTION__, 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 begining 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;