irlap_event.c

linux 内核源代码

		self->retry_count = 0;

		/* Wait for turnaround time to give a chance to the other
		 * device to be ready to receive us.
		 * Note : the time to switch speed is typically larger
		 * than the turnaround time, but as we don't have the other
		 * side speed switch time, that's our best guess...
		 * Jean II */
		irlap_wait_min_turn_around(self, &self->qos_tx);

		/* This frame will actually be sent at the new speed */
		irlap_send_rr_frame(self, CMD_FRAME);

		/* The timer is set to half the normal timer to quickly
		 * detect a failure to negociate the new connection
		 * parameters. IrLAP 6.11.3.2, note 3.
		 * Note that currently we don't process this failure
		 * properly, as we should do a quick disconnect.
		 * Jean II */
		irlap_start_final_timer(self, self->final_timeout/2);
		irlap_next_state(self, LAP_NRM_P);

		irlap_connect_confirm(self, skb);
		break;
	case RECV_DM_RSP:     /* FALLTHROUGH */
	case RECV_DISC_CMD:
		del_timer(&self->final_timer);
		irlap_next_state(self, LAP_NDM);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %d, %s\n", __FUNCTION__,
			   event, irlap_event[event]);

		ret = -1;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_offline (self, event, skb, info)
 *
 *    OFFLINE state, not used for now!
 *
 */
static int irlap_state_offline(struct irlap_cb *self, IRLAP_EVENT event,
			       struct sk_buff *skb, struct irlap_info *info)
{
	IRDA_DEBUG( 0, "%s(), Unknown event\n", __FUNCTION__);

	return -1;
}

/*
 * Function irlap_state_xmit_p (self, event, skb, info)
 *
 *    XMIT, Only the primary station has right to transmit, and we
 *    therefore do not expect to receive any transmissions from other
 *    stations.
 *
 */
static int irlap_state_xmit_p(struct irlap_cb *self, IRLAP_EVENT event,
			      struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	switch (event) {
	case SEND_I_CMD:
		/*
		 *  Only send frame if send-window > 0.
		 */
		if ((self->window > 0) && (!self->remote_busy)) {
			int nextfit;
#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
			struct sk_buff *skb_next;

			/* With DYNAMIC_WINDOW, we keep the window size
			 * maximum, and adapt on the packets we are sending.
			 * At 115k, we can send only 2 packets of 2048 bytes
			 * in a 500 ms turnaround. Without this option, we
			 * would always limit the window to 2. With this
			 * option, if we send smaller packets, we can send
			 * up to 7 of them (always depending on QoS).
			 * Jean II */

			/* Look at the next skb. This is safe, as we are
			 * the only consumer of the Tx queue (if we are not,
			 * we have other problems) - Jean II */
			skb_next = skb_peek(&self->txq);

			/* Check if a subsequent skb exist and would fit in
			 * the current window (with respect to turnaround
			 * time).
			 * This allow us to properly mark the current packet
			 * with the pf bit, to avoid falling back on the
			 * second test below, and avoid waiting the
			 * end of the window and sending a extra RR.
			 * Note : (skb_next != NULL) <=> (skb_queue_len() > 0)
			 * Jean II */
			nextfit = ((skb_next != NULL) &&
				   ((skb_next->len + skb->len) <=
				    self->bytes_left));

			/*
			 * The current packet may not fit ! Because of test
			 * above, this should not happen any more !!!
			 *  Test if we have transmitted more bytes over the
			 *  link than its possible to do with the current
			 *  speed and turn-around-time.
			 */
			if((!nextfit) && (skb->len > self->bytes_left)) {
				IRDA_DEBUG(0, "%s(), Not allowed to transmit"
					   " more bytes!\n", __FUNCTION__);
				/* Requeue the skb */
				skb_queue_head(&self->txq, skb_get(skb));
				/*
				 *  We should switch state to LAP_NRM_P, but
				 *  that is not possible since we must be sure
				 *  that we poll the other side. Since we have
				 *  used up our time, the poll timer should
				 *  trigger anyway now, so we just wait for it
				 *  DB
				 */
				/*
				 * Sorry, but that's not totally true. If
				 * we send 2000B packets, we may wait another
				 * 1000B until our turnaround expire. That's
				 * why we need to be proactive in avoiding
				 * coming here. - Jean II
				 */
				return -EPROTO;
			}

			/* Substract space used by this skb */
			self->bytes_left -= skb->len;
#else	/* CONFIG_IRDA_DYNAMIC_WINDOW */
			/* Window has been adjusted for the max packet
			 * size, so much simpler... - Jean II */
			nextfit = !skb_queue_empty(&self->txq);
#endif	/* CONFIG_IRDA_DYNAMIC_WINDOW */
			/*
			 *  Send data with poll bit cleared only if window > 1
			 *  and there is more frames after this one to be sent
			 */
			if ((self->window > 1) && (nextfit)) {
				/* More packet to send in current window */
				irlap_send_data_primary(self, skb);
				irlap_next_state(self, LAP_XMIT_P);
			} else {
				/* Final packet of window */
				irlap_send_data_primary_poll(self, skb);

				/*
				 * Make sure state machine does not try to send
				 * any more frames
				 */
				ret = -EPROTO;
			}
#ifdef CONFIG_IRDA_FAST_RR
			/* Peer may want to reply immediately */
			self->fast_RR = FALSE;
#endif /* CONFIG_IRDA_FAST_RR */
		} else {
			IRDA_DEBUG(4, "%s(), Unable to send! remote busy?\n",
				   __FUNCTION__);
			skb_queue_head(&self->txq, skb_get(skb));

			/*
			 *  The next ret is important, because it tells
			 *  irlap_next_state _not_ to deliver more frames
			 */
			ret = -EPROTO;
		}
		break;
	case POLL_TIMER_EXPIRED:
		IRDA_DEBUG(3, "%s(), POLL_TIMER_EXPIRED <%ld>\n",
			    __FUNCTION__, jiffies);
		irlap_send_rr_frame(self, CMD_FRAME);
		/* Return to NRM properly - Jean II  */
		self->window = self->window_size;
#ifdef CONFIG_IRDA_DYNAMIC_WINDOW
		/* Allowed to transmit a maximum number of bytes again. */
		self->bytes_left = self->line_capacity;
#endif /* CONFIG_IRDA_DYNAMIC_WINDOW */
		irlap_start_final_timer(self, self->final_timeout);
		irlap_next_state(self, LAP_NRM_P);
		break;
	case DISCONNECT_REQUEST:
		del_timer(&self->poll_timer);
		irlap_wait_min_turn_around(self, &self->qos_tx);
		irlap_send_disc_frame(self);
		irlap_flush_all_queues(self);
		irlap_start_final_timer(self, self->final_timeout);
		self->retry_count = 0;
		irlap_next_state(self, LAP_PCLOSE);
		break;
	case DATA_REQUEST:
		/* Nothing to do, irlap_do_event() will send the packet
		 * when we return... - Jean II */
		break;
	default:
		IRDA_DEBUG(0, "%s(), Unknown event %s\n",
			   __FUNCTION__, irlap_event[event]);

		ret = -EINVAL;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_pclose (event, skb, info)
 *
 *    PCLOSE state
 */
static int irlap_state_pclose(struct irlap_cb *self, IRLAP_EVENT event,
			      struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(1, "%s()\n", __FUNCTION__);

	IRDA_ASSERT(self != NULL, return -1;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -1;);

	switch (event) {
	case RECV_UA_RSP: /* FALLTHROUGH */
	case RECV_DM_RSP:
		del_timer(&self->final_timer);

		/* Set new link parameters */
		irlap_apply_default_connection_parameters(self);

		/* Always switch state before calling upper layers */
		irlap_next_state(self, LAP_NDM);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	case FINAL_TIMER_EXPIRED:
		if (self->retry_count < self->N3) {
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_disc_frame(self);
			irlap_start_final_timer(self, self->final_timeout);
			self->retry_count++;
			/* Keep state */
		} else {
			irlap_apply_default_connection_parameters(self);

			/*  Always switch state before calling upper layers */
			irlap_next_state(self, LAP_NDM);

			irlap_disconnect_indication(self, LAP_NO_RESPONSE);
		}
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %d\n", __FUNCTION__, event);

		ret = -1;
		break;
	}
	return ret;
}

/*
 * Function irlap_state_nrm_p (self, event, skb, info)
 *
 *   NRM_P (Normal Response Mode as Primary), The primary station has given
 *   permissions to a secondary station to transmit IrLAP resonse frames
 *   (by sending a frame with the P bit set). The primary station will not
 *   transmit any frames and is expecting to receive frames only from the
 *   secondary to which transmission permissions has been given.
 */
static int irlap_state_nrm_p(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;
	int ns_status;
	int nr_status;

	switch (event) {
	case RECV_I_RSP: /* Optimize for the common case */
		/* FIXME: must check for remote_busy below */
#ifdef CONFIG_IRDA_FAST_RR
		/*
		 *  Reset the fast_RR so we can use the fast RR code with
		 *  full speed the next time since peer may have more frames
		 *  to transmitt
		 */
		self->fast_RR = FALSE;
#endif /* CONFIG_IRDA_FAST_RR */
		IRDA_ASSERT( info != NULL, return -1;);

		ns_status = irlap_validate_ns_received(self, info->ns);
		nr_status = irlap_validate_nr_received(self, info->nr);

		/*
		 *  Check for expected I(nformation) frame
		 */
		if ((ns_status == NS_EXPECTED) && (nr_status == NR_EXPECTED)) {

			/* Update Vr (next frame for us to receive) */
			self->vr = (self->vr + 1) % 8;

			/* Update Nr received, cleanup our retry queue */
			irlap_update_nr_received(self, info->nr);

			/*
			 *  Got expected NR, so reset the
			 *  retry_count. This is not done by IrLAP spec,
			 *  which is strange!
			 */
			self->retry_count = 0;
			self->ack_required = TRUE;

			/*  poll bit cleared?  */
			if (!info->pf) {
				/* Keep state, do not move this line */
				irlap_next_state(self, LAP_NRM_P);

				irlap_data_indication(self, skb, FALSE);
			} else {
				/* No longer waiting for pf */
				del_timer(&self->final_timer);

				irlap_wait_min_turn_around(self, &self->qos_tx);

				/* Call higher layer *before* changing state
				 * to give them a chance to send data in the
				 * next LAP frame.
				 * Jean II */
				irlap_data_indication(self, skb, FALSE);

				/* XMIT states are the most dangerous state
				 * to be in, because user requests are
				 * processed directly and may change state.
				 * On the other hand, in NDM_P, those
				 * requests are queued and we will process
				 * them when we return to irlap_do_event().
				 * Jean II
				 */
				irlap_next_state(self, LAP_XMIT_P);

				/* This is the last frame.
				 * Make sure it's always called in XMIT state.
				 * - Jean II */
				irlap_start_poll_timer(self, self->poll_timeout);
			}
			break;

		}
		/* Unexpected next to send (Ns) */
		if ((ns_status == NS_UNEXPECTED) && (nr_status == NR_EXPECTED))
		{
			if (!info->pf) {
				irlap_update_nr_received(self, info->nr);

				/*
				 *  Wait until the last frame before doing
				 *  anything
				 */

				/* Keep state */
				irlap_next_state(self, LAP_NRM_P);
			} else {
				IRDA_DEBUG(4,
				       "%s(), missing or duplicate frame!\n",
					   __FUNCTION__);

				/* Update Nr received */
				irlap_update_nr_received(self, info->nr);

				irlap_wait_min_turn_around(self, &self->qos_tx);
				irlap_send_rr_frame(self, CMD_FRAME);

				self->ack_required = FALSE;

				irlap_start_final_timer(self, self->final_timeout);
				irlap_next_state(self, LAP_NRM_P);
			}
			break;
		}
		/*
		 *  Unexpected next to receive (Nr)
		 */
		if ((ns_status == NS_EXPECTED) && (nr_status == NR_UNEXPECTED))
		{
			if (info->pf) {
				self->vr = (self->vr + 1) % 8;

				/* Update Nr received */
				irlap_update_nr_received(self, info->nr);

				/* Resend rejected frames */
				irlap_resend_rejected_frames(self, CMD_FRAME);

				self->ack_required = FALSE;

				/* Make sure we account for the time
				 * to transmit our frames. See comemnts
				 * in irlap_send_data_primary_poll().
				 * Jean II */
				irlap_start_final_timer(self, 2 * self->final_timeout);

				/* Keep state, do not move this line */
				irlap_next_state(self, LAP_NRM_P);

				irlap_data_indication(self, skb, FALSE);
			} else {
				/*
				 *  Do not resend frames until the last
				 *  frame has arrived from the other
				 *  device. This is not documented in
				 *  IrLAP!!
				 */
				self->vr = (self->vr + 1) % 8;

				/* Update Nr received */
				irlap_update_nr_received(self, info->nr);

				self->ack_required = FALSE;

				/* Keep state, do not move this line!*/
				irlap_next_state(self, LAP_NRM_P);

				irlap_data_indication(self, skb, FALSE);
			}
			break;
		}
		/*
		 *  Unexpected next to send (Ns) and next to receive (Nr)
		 *  Not documented by IrLAP!
		 */
		if ((ns_status == NS_UNEXPECTED) &&
		    (nr_status == NR_UNEXPECTED))
		{
			IRDA_DEBUG(4, "%s(), unexpected nr and ns!\n",
				   __FUNCTION__);
			if (info->pf) {
				/* Resend rejected frames */
				irlap_resend_rejected_frames(self, CMD_FRAME);

				/* Give peer some time to retransmit!
				 * But account for our own Tx. */
				irlap_start_final_timer(self, 2 * self->final_timeout);

				/* Keep state, do not move this line */
				irlap_next_state(self, LAP_NRM_P);
			} else {
				/* Update Nr received */
				/* irlap_update_nr_received( info->nr); */

				self->ack_required = FALSE;
			}
			break;
		}

		/*