irlap_event.c

linux 内核源代码

	}
	return ret;
}

/*
 * Function irlap_state_nrm_s (event, skb, info)
 *
 *    NRM_S (Normal Response Mode as Secondary) state, in this state we are
 *    expecting to receive frames from the primary station
 *
 */
static int irlap_state_nrm_s(struct irlap_cb *self, IRLAP_EVENT event,
			     struct sk_buff *skb, struct irlap_info *info)
{
	int ns_status;
	int nr_status;
	int ret = 0;

	IRDA_DEBUG(4, "%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_I_CMD: /* Optimize for the common case */
		/* FIXME: must check for remote_busy below */
		IRDA_DEBUG(4, "%s(), event=%s nr=%d, vs=%d, ns=%d, "
			   "vr=%d, pf=%d\n", __FUNCTION__,
			   irlap_event[event], info->nr,
			   self->vs, info->ns, self->vr, info->pf);

		self->retry_count = 0;

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

			/*
			 *  poll bit cleared?
			 */
			if (!info->pf) {

				self->ack_required = TRUE;

				/*
				 *  Starting WD-timer here is optional, but
				 *  not recommended. Note 6 IrLAP p. 83
				 */
#if 0
				irda_start_timer(WD_TIMER, self->wd_timeout);
#endif
				/* Keep state, do not move this line */
				irlap_next_state(self, LAP_NRM_S);

				irlap_data_indication(self, skb, FALSE);
				break;
			} else {
				/*
				 *  We should wait before sending RR, and
				 *  also before changing to XMIT_S
				 *  state. (note 1, IrLAP p. 82)
				 */
				irlap_wait_min_turn_around(self, &self->qos_tx);

				/*
				 * Give higher layers a chance to
				 * immediately reply with some data before
				 * we decide if we should send a RR frame
				 * or not
				 */
				irlap_data_indication(self, skb, FALSE);

				/* Any pending data requests?  */
				if (!skb_queue_empty(&self->txq) &&
				    (self->window > 0))
				{
					self->ack_required = TRUE;

					del_timer(&self->wd_timer);

					irlap_next_state(self, LAP_XMIT_S);
				} else {
					irlap_send_rr_frame(self, RSP_FRAME);
					irlap_start_wd_timer(self,
							     self->wd_timeout);

					/* Keep the state */
					irlap_next_state(self, LAP_NRM_S);
				}
				break;
			}
		}
		/*
		 *  Check for Unexpected next to send (Ns)
		 */
		if ((ns_status == NS_UNEXPECTED) && (nr_status == NR_EXPECTED))
		{
			/* Unexpected next to send, with final bit cleared */
			if (!info->pf) {
				irlap_update_nr_received(self, info->nr);

				irlap_start_wd_timer(self, self->wd_timeout);
			} else {
				/* Update Nr received */
				irlap_update_nr_received(self, info->nr);

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

				irlap_start_wd_timer(self, self->wd_timeout);
			}
			break;
		}

		/*
		 *  Unexpected Next to Receive(NR) ?
		 */
		if ((ns_status == NS_EXPECTED) && (nr_status == NR_UNEXPECTED))
		{
			if (info->pf) {
				IRDA_DEBUG(4, "RECV_I_RSP: frame(s) lost\n");

				self->vr = (self->vr + 1) % 8;

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

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

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

				irlap_data_indication(self, skb, FALSE);
				irlap_start_wd_timer(self, self->wd_timeout);
				break;
			}
			/*
			 *  This is not documented in IrLAP!! Unexpected NR
			 *  with poll bit cleared
			 */
			if (!info->pf) {
				self->vr = (self->vr + 1) % 8;

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

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

				irlap_data_indication(self, skb, FALSE);
				irlap_start_wd_timer(self, self->wd_timeout);
			}
			break;
		}

		if (ret == NR_INVALID) {
			IRDA_DEBUG(0, "NRM_S, NR_INVALID not implemented!\n");
		}
		if (ret == NS_INVALID) {
			IRDA_DEBUG(0, "NRM_S, NS_INVALID not implemented!\n");
		}
		break;
	case RECV_UI_FRAME:
		/*
		 *  poll bit cleared?
		 */
		if (!info->pf) {
			irlap_data_indication(self, skb, TRUE);
			irlap_next_state(self, LAP_NRM_S); /* Keep state */
		} else {
			/*
			 *  Any pending data requests?
			 */
			if (!skb_queue_empty(&self->txq) &&
			    (self->window > 0) && !self->remote_busy)
			{
				irlap_data_indication(self, skb, TRUE);

				del_timer(&self->wd_timer);

				irlap_next_state(self, LAP_XMIT_S);
			} else {
				irlap_data_indication(self, skb, TRUE);

				irlap_wait_min_turn_around(self, &self->qos_tx);

				irlap_send_rr_frame(self, RSP_FRAME);
				self->ack_required = FALSE;

				irlap_start_wd_timer(self, self->wd_timeout);

				/* Keep the state */
				irlap_next_state(self, LAP_NRM_S);
			}
		}
		break;
	case RECV_RR_CMD:
		self->retry_count = 0;

		/*
		 *  Nr as expected?
		 */
		nr_status = irlap_validate_nr_received(self, info->nr);
		if (nr_status == NR_EXPECTED) {
			if (!skb_queue_empty(&self->txq) &&
			    (self->window > 0)) {
				self->remote_busy = FALSE;

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

				irlap_wait_min_turn_around(self, &self->qos_tx);
				irlap_next_state(self, LAP_XMIT_S);
			} else {
				self->remote_busy = FALSE;
				/* Update Nr received */
				irlap_update_nr_received(self, info->nr);
				irlap_wait_min_turn_around(self, &self->qos_tx);
				irlap_start_wd_timer(self, self->wd_timeout);

				/* Note : if the link is idle (this case),
				 * we never go in XMIT_S, so we never get a
				 * chance to process any DISCONNECT_REQUEST.
				 * Do it now ! - Jean II */
				if (self->disconnect_pending) {
					/* Disconnect */
					irlap_send_rd_frame(self);
					irlap_flush_all_queues(self);

					irlap_next_state(self, LAP_SCLOSE);
				} else {
					/* Just send back pf bit */
					irlap_send_rr_frame(self, RSP_FRAME);

					irlap_next_state(self, LAP_NRM_S);
				}
			}
		} else if (nr_status == NR_UNEXPECTED) {
			self->remote_busy = FALSE;
			irlap_update_nr_received(self, info->nr);
			irlap_resend_rejected_frames(self, RSP_FRAME);

			irlap_start_wd_timer(self, self->wd_timeout);

			/* Keep state */
			irlap_next_state(self, LAP_NRM_S);
		} else {
			IRDA_DEBUG(1, "%s(), invalid nr not implemented!\n",
				   __FUNCTION__);
		}
		break;
	case RECV_SNRM_CMD:
		/* SNRM frame is not allowed to contain an I-field */
		if (!info) {
			del_timer(&self->wd_timer);
			IRDA_DEBUG(1, "%s(), received SNRM cmd\n", __FUNCTION__);
			irlap_next_state(self, LAP_RESET_CHECK);

			irlap_reset_indication(self);
		} else {
			IRDA_DEBUG(0,
				   "%s(), SNRM frame contained an I-field!\n",
				   __FUNCTION__);

		}
		break;
	case RECV_REJ_CMD:
		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, RSP_FRAME);
		} else
			irlap_resend_rejected_frames(self, RSP_FRAME);
		irlap_start_wd_timer(self, self->wd_timeout);
		break;
	case RECV_SREJ_CMD:
		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, RSP_FRAME);
		} else
			irlap_resend_rejected_frame(self, RSP_FRAME);
		irlap_start_wd_timer(self, self->wd_timeout);
		break;
	case WD_TIMER_EXPIRED:
		/*
		 *  Wait until retry_count * n matches negotiated threshold/
		 *  disconnect time (note 2 in IrLAP p. 82)
		 *
		 * Similar to irlap_state_nrm_p() -> FINAL_TIMER_EXPIRED
		 * Note : self->wd_timeout = (self->final_timeout * 2),
		 *   which explain why we use (self->N2 / 2) here !!!
		 * Jean II
		 */
		IRDA_DEBUG(1, "%s(), retry_count = %d\n", __FUNCTION__,
			   self->retry_count);

		if (self->retry_count < (self->N2 / 2)) {
			/* No retry, just wait for primary */
			irlap_start_wd_timer(self, self->wd_timeout);
			self->retry_count++;

			if((self->retry_count % (self->N1 / 2)) == 0)
				irlap_status_indication(self,
							STATUS_NO_ACTIVITY);
		} 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_DISC_CMD:
		/* Always switch state before calling upper layers */
		irlap_next_state(self, LAP_NDM);

		/* Send disconnect response */
		irlap_wait_min_turn_around(self, &self->qos_tx);
		irlap_send_ua_response_frame(self, NULL);

		del_timer(&self->wd_timer);
		irlap_flush_all_queues(self);
		/* Set default link parameters */
		irlap_apply_default_connection_parameters(self);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	case RECV_DISCOVERY_XID_CMD:
		irlap_wait_min_turn_around(self, &self->qos_tx);
		irlap_send_rr_frame(self, RSP_FRAME);
		self->ack_required = TRUE;
		irlap_start_wd_timer(self, self->wd_timeout);
		irlap_next_state(self, LAP_NRM_S);

		break;
	case RECV_TEST_CMD:
		/* Remove test frame header (only LAP header in NRM) */
		skb_pull(skb, LAP_ADDR_HEADER + LAP_CTRL_HEADER);

		irlap_wait_min_turn_around(self, &self->qos_tx);
		irlap_start_wd_timer(self, self->wd_timeout);

		/* Send response (info will be copied) */
		irlap_send_test_frame(self, self->caddr, info->daddr, skb);
		break;
	default:
		IRDA_DEBUG(1, "%s(), Unknown event %d, (%s)\n", __FUNCTION__,
			   event, irlap_event[event]);

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

/*
 * Function irlap_state_sclose (self, event, skb, info)
 */
static int irlap_state_sclose(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 -ENODEV;);
	IRDA_ASSERT(self->magic == LAP_MAGIC, return -EBADR;);

	switch (event) {
	case RECV_DISC_CMD:
		/* Always switch state before calling upper layers */
		irlap_next_state(self, LAP_NDM);

		/* Send disconnect response */
		irlap_wait_min_turn_around(self, &self->qos_tx);
		irlap_send_ua_response_frame(self, NULL);

		del_timer(&self->wd_timer);
		/* Set default link parameters */
		irlap_apply_default_connection_parameters(self);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	case RECV_DM_RSP:
		/* IrLAP-1.1 p.82: in SCLOSE, S and I type RSP frames
		 * shall take us down into default NDM state, like DM_RSP
		 */
	case RECV_RR_RSP:
	case RECV_RNR_RSP:
	case RECV_REJ_RSP:
	case RECV_SREJ_RSP:
	case RECV_I_RSP:
		/* Always switch state before calling upper layers */
		irlap_next_state(self, LAP_NDM);

		del_timer(&self->wd_timer);
		irlap_apply_default_connection_parameters(self);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	case WD_TIMER_EXPIRED:
		/* Always switch state before calling upper layers */
		irlap_next_state(self, LAP_NDM);

		irlap_apply_default_connection_parameters(self);

		irlap_disconnect_indication(self, LAP_DISC_INDICATION);
		break;
	default:
		/* IrLAP-1.1 p.82: in SCLOSE, basically any received frame
		 * with pf=1 shall restart the wd-timer and resend the rd:rsp
		 */
		if (info != NULL  &&  info->pf) {
			del_timer(&self->wd_timer);
			irlap_wait_min_turn_around(self, &self->qos_tx);
			irlap_send_rd_frame(self);
			irlap_start_wd_timer(self, self->wd_timeout);
			break;		/* stay in SCLOSE */
		}

		IRDA_DEBUG(1, "%s(), Unknown event %d, (%s)\n", __FUNCTION__,
			   event, irlap_event[event]);

		ret = -EINVAL;
		break;
	}

	return -1;
}

static int irlap_state_reset_check( struct irlap_cb *self, IRLAP_EVENT event,
				   struct sk_buff *skb,
				   struct irlap_info *info)
{
	int ret = 0;

	IRDA_DEBUG(1, "%s(), event=%s\n", __FUNCTION__, irlap_event[event]);

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

	switch (event) {