irlap_event.c

linux 内核源代码

		 *  Invalid NR or NS
		 */
		if ((nr_status == NR_INVALID) || (ns_status == NS_INVALID)) {
			if (info->pf) {
				del_timer(&self->final_timer);

				irlap_next_state(self, LAP_RESET_WAIT);

				irlap_disconnect_indication(self, LAP_RESET_INDICATION);
				self->xmitflag = TRUE;
			} else {
				del_timer(&self->final_timer);

				irlap_disconnect_indication(self, LAP_RESET_INDICATION);

				self->xmitflag = FALSE;
			}
			break;
		}
		IRDA_DEBUG(1, "%s(), Not implemented!\n", __FUNCTION__);
		IRDA_DEBUG(1, "%s(), event=%s, ns_status=%d, nr_status=%d\n",
		       __FUNCTION__, irlap_event[event], ns_status, nr_status);
		break;
	case RECV_UI_FRAME:
		/* Poll bit cleared? */
		if (!info->pf) {
			irlap_data_indication(self, skb, TRUE);
			irlap_next_state(self, LAP_NRM_P);
		} else {
			del_timer(&self->final_timer);
			irlap_data_indication(self, skb, TRUE);
			irlap_next_state(self, LAP_XMIT_P);
			IRDA_DEBUG(1, "%s: RECV_UI_FRAME: next state %s\n", __FUNCTION__, irlap_state[self->state]);
			irlap_start_poll_timer(self, self->poll_timeout);
		}
		break;
	case RECV_RR_RSP:
		/*
		 *  If you get a RR, the remote isn't busy anymore,
		 *  no matter what the NR
		 */
		self->remote_busy = FALSE;

		/* Stop final timer */
		del_timer(&self->final_timer);

		/*
		 *  Nr as expected?
		 */
		ret = irlap_validate_nr_received(self, info->nr);
		if (ret == NR_EXPECTED) {
			/* Update Nr received */
			irlap_update_nr_received(self, info->nr);

			/*
			 *  Got expected NR, so reset the retry_count. This
			 *  is not done by the IrLAP standard , which is
			 *  strange! DB.
			 */
			self->retry_count = 0;
			irlap_wait_min_turn_around(self, &self->qos_tx);

			irlap_next_state(self, LAP_XMIT_P);

			/* Start poll timer */
			irlap_start_poll_timer(self, self->poll_timeout);
		} else if (ret == NR_UNEXPECTED) {
			IRDA_ASSERT(info != NULL, return -1;);
			/*
			 *  Unexpected nr!
			 */

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

			IRDA_DEBUG(4, "RECV_RR_FRAME: Retrans:%d, nr=%d, va=%d, "
			      "vs=%d, vr=%d\n",
			      self->retry_count, info->nr, self->va,
			      self->vs, self->vr);

			/* Resend rejected frames */
			irlap_resend_rejected_frames(self, CMD_FRAME);
			irlap_start_final_timer(self, self->final_timeout * 2);

			irlap_next_state(self, LAP_NRM_P);
		} else if (ret == NR_INVALID) {
			IRDA_DEBUG(1, "%s(), Received RR with "
				   "invalid nr !\n", __FUNCTION__);

			irlap_next_state(self, LAP_RESET_WAIT);

			irlap_disconnect_indication(self, LAP_RESET_INDICATION);
			self->xmitflag = TRUE;
		}
		break;
	case RECV_RNR_RSP:
		IRDA_ASSERT(info != NULL, return -1;);

		/* Stop final timer */
		del_timer(&self->final_timer);
		self->remote_busy = TRUE;

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

		/* Start poll timer */
		irlap_start_poll_timer(self, self->poll_timeout);
		break;
	case RECV_FRMR_RSP:
		del_timer(&self->final_timer);
		self->xmitflag = TRUE;
		irlap_next_state(self, LAP_RESET_WAIT);
		irlap_reset_indication(self);
		break;
	case FINAL_TIMER_EXPIRED:
		/*
		 *  We are allowed to wait for additional 300 ms if
		 *  final timer expires when we are in the middle
		 *  of receiving a frame (page 45, IrLAP). Check that
		 *  we only do this once for each frame.
		 */
		if (irda_device_is_receiving(self->netdev) && !self->add_wait) {
			IRDA_DEBUG(1, "FINAL_TIMER_EXPIRED when receiving a "
			      "frame! Waiting a little bit more!\n");
			irlap_start_final_timer(self, msecs_to_jiffies(300));

			/*
			 *  Don't allow this to happen one more time in a row,
			 *  or else we can get a pretty tight loop here if
			 *  if we only receive half a frame. DB.
			 */
			self->add_wait = TRUE;
			break;
		}
		self->add_wait = FALSE;

		/* N2 is the disconnect timer. Until we reach it, we retry */
		if (self->retry_count < self->N2) {
			/* Retry sending the pf bit to the secondary */
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_rr_frame(self, CMD_FRAME);

			irlap_start_final_timer(self, self->final_timeout);
			self->retry_count++;
			IRDA_DEBUG(4, "irlap_state_nrm_p: FINAL_TIMER_EXPIRED:"
				   " retry_count=%d\n", self->retry_count);

			/* Early warning event. I'm using a pretty liberal
			 * interpretation of the spec and generate an event
			 * every time the timer is multiple of N1 (and not
			 * only the first time). This allow application
			 * to know precisely if connectivity restart...
			 * Jean II */
			if((self->retry_count % self->N1) == 0)
				irlap_status_indication(self,
							STATUS_NO_ACTIVITY);

			/* 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;
	case RECV_REJ_RSP:
		irlap_update_nr_received(self, info->nr);
		if (self->remote_busy) {
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_rr_frame(self, CMD_FRAME);
		} else
			irlap_resend_rejected_frames(self, CMD_FRAME);
		irlap_start_final_timer(self, 2 * self->final_timeout);
		break;
	case RECV_SREJ_RSP:
		irlap_update_nr_received(self, info->nr);
		if (self->remote_busy) {
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_rr_frame(self, CMD_FRAME);
		} else
			irlap_resend_rejected_frame(self, CMD_FRAME);
		irlap_start_final_timer(self, 2 * self->final_timeout);
		break;
	case RECV_RD_RSP:
		IRDA_DEBUG(1, "%s(), RECV_RD_RSP\n", __FUNCTION__);

		irlap_flush_all_queues(self);
		irlap_next_state(self, LAP_XMIT_P);
		/* Call back the LAP state machine to do a proper disconnect */
		irlap_disconnect_request(self);
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %s\n",
			    __FUNCTION__, irlap_event[event]);

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

/*
 * Function irlap_state_reset_wait (event, skb, info)
 *
 *    We have informed the service user of a reset condition, and is
 *    awaiting reset of disconnect request.
 *
 */
static int irlap_state_reset_wait(struct irlap_cb *self, IRLAP_EVENT event,
				  struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(3, "%s(), event = %s\n", __FUNCTION__, irlap_event[event]);

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

	switch (event) {
	case RESET_REQUEST:
		if (self->xmitflag) {
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_snrm_frame(self, NULL);
			irlap_start_final_timer(self, self->final_timeout);
			irlap_next_state(self, LAP_RESET);
		} else {
			irlap_start_final_timer(self, self->final_timeout);
			irlap_next_state(self, LAP_RESET);
		}
		break;
	case DISCONNECT_REQUEST:
		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;
	default:
		IRDA_DEBUG(2, "%s(), Unknown event %s\n", __FUNCTION__,
			   irlap_event[event]);

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

/*
 * Function irlap_state_reset (self, event, skb, info)
 *
 *    We have sent a SNRM reset command to the peer layer, and is awaiting
 *    reply.
 *
 */
static int irlap_state_reset(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(3, "%s(), event = %s\n", __FUNCTION__, irlap_event[event]);

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

	switch (event) {
	case RECV_DISC_CMD:
		del_timer(&self->final_timer);

		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;
	case RECV_UA_RSP:
		del_timer(&self->final_timer);

		/* Initiate connection state */
		irlap_initiate_connection_state(self);

		irlap_reset_confirm();

		self->remote_busy = FALSE;

		irlap_next_state(self, LAP_XMIT_P);

		irlap_start_poll_timer(self, self->poll_timeout);

		break;
	case FINAL_TIMER_EXPIRED:
		if (self->retry_count < 3) {
			irlap_wait_min_turn_around(self, &self->qos_tx);

			IRDA_ASSERT(self->netdev != NULL, return -1;);
			irlap_send_snrm_frame(self, self->qos_dev);

			self->retry_count++; /* Experimental!! */

			irlap_start_final_timer(self, self->final_timeout);
			irlap_next_state(self, LAP_RESET);
		} else if (self->retry_count >= self->N3) {
			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;
	case RECV_SNRM_CMD:
		/*
		 * SNRM frame is not allowed to contain an I-field in this
		 * state
		 */
		if (!info) {
			IRDA_DEBUG(3, "%s(), RECV_SNRM_CMD\n", __FUNCTION__);
			irlap_initiate_connection_state(self);
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_ua_response_frame(self, &self->qos_rx);
			irlap_reset_confirm();
			irlap_start_wd_timer(self, self->wd_timeout);
			irlap_next_state(self, LAP_NDM);
		} else {
			IRDA_DEBUG(0,
				   "%s(), SNRM frame contained an I field!\n",
				   __FUNCTION__);
		}
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %s\n",
			   __FUNCTION__, irlap_event[event]);

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

/*
 * Function irlap_state_xmit_s (event, skb, info)
 *
 *   XMIT_S, The secondary station has been given the right to transmit,
 *   and we therefor do not expect to receive any transmissions from other
 *   stations.
 */
static int irlap_state_xmit_s(struct irlap_cb *self, IRLAP_EVENT event,
			      struct sk_buff *skb, struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(4, "%s(), event=%s\n", __FUNCTION__, irlap_event[event]);

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

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

			/*
			 * Same deal as in irlap_state_xmit_p(), so see
			 * the comments at that point.
			 * We are the secondary, so there are only subtle
			 * differences. - Jean II
			 */

			/* Check if a subsequent skb exist and would fit in
			 * the current window (with respect to turnaround
			 * time). - Jean II */
			skb_next = skb_peek(&self->txq);
			nextfit = ((skb_next != NULL) &&
				   ((skb_next->len + skb->len) <=
				    self->bytes_left));

			/*
			 *  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));

				/*
				 *  Switch to NRM_S, this is only possible
				 *  when we are in secondary mode, since we
				 *  must be sure that we don't miss any RR
				 *  frames
				 */
				self->window = self->window_size;
				self->bytes_left = self->line_capacity;
				irlap_start_wd_timer(self, self->wd_timeout);

				irlap_next_state(self, LAP_NRM_S);
				/* Slight difference with primary :
				 * here we would wait for the other side to
				 * expire the turnaround. - Jean II */

				return -EPROTO; /* Try again later */
			}
			/* 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 final bit cleared only if window > 1
			 *  and there is more frames to be sent
			 */
			if ((self->window > 1) && (nextfit)) {
				irlap_send_data_secondary(self, skb);
				irlap_next_state(self, LAP_XMIT_S);
			} else {
				irlap_send_data_secondary_final(self, skb);
				irlap_next_state(self, LAP_NRM_S);

				/*
				 * Make sure state machine does not try to send
				 * any more frames
				 */
				ret = -EPROTO;
			}
		} else {
			IRDA_DEBUG(2, "%s(), Unable to send!\n", __FUNCTION__);
			skb_queue_head(&self->txq, skb_get(skb));
			ret = -EPROTO;
		}
		break;
	case DISCONNECT_REQUEST:
		irlap_send_rd_frame(self);
		irlap_flush_all_queues(self);
		irlap_start_wd_timer(self, self->wd_timeout);
		irlap_next_state(self, LAP_SCLOSE);
		break;
	case DATA_REQUEST:
		/* Nothing to do, irlap_do_event() will send the packet
		 * when we return... - Jean II */
		break;
	default:
		IRDA_DEBUG(2, "%s(), Unknown event %s\n", __FUNCTION__,
			   irlap_event[event]);

		ret = -EINVAL;
		break;