libpri/doc/cc_ptmp_monitor.fsm

/*
 * FSM pseudo code used in the design/implementation of the CC PTMP monitor.
 *
 * The CCBSStatusRequest messages are handled independently from this FSM.
 *
 * The CCBSInterrogate/CCNRInterrogate messages are initiated by a dialplan
 * application/AMI/CLI (future) and are handled outside of this FSM.
 */
FSM CC_PTMP_Monitor
{
	State CC_STATE_IDLE {
		Init {
		}
		Prolog {
			Action Set_Selfdestruct;
		}
		Stimulus CC_EVENT_AVAILABLE {
			/*
			 * Before event is posted:
			 *   Received CallInfoRetain
			 *   Created cc_record
			 *   Saved CallLinkageID
			 */
			Action Pass_Up_CC_Available;
			Next_State CC_STATE_AVAILABLE;
		}
		Stimulus CC_EVENT_CANCEL {
			Action Set_Selfdestruct;
		}
	}
	State CC_STATE_AVAILABLE {
		/*
		 * The upper layer is responsible for canceling the CC available
		 * offering as a safeguard in case the network cable is disconnected.
		 * The timer should be set much longer than the network T_RETENTION
		 * timer so normally the CC records will be cleaned up by network
		 * activity.
		 */
		Stimulus CC_EVENT_CC_REQUEST {
			/* cc_record->is_ccnr is set before event posted. */
			Action Queue_CC_Request;
			Action Start_T_ACTIVATE;
			Next_State CC_STATE_REQUESTED;
		}
		Stimulus CC_EVENT_TIMEOUT_T_RETENTION {
			/*
			 * Received EraseCallLinkageID
			 * T_RETENTION expired on the network side so we will pretend
			 * that it expired on our side.
			 */
			Action Pass_Up_CC_Cancel;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_CANCEL {
			Next_State CC_STATE_IDLE;
		}
	}
	State CC_STATE_REQUESTED {
		Stimulus CC_EVENT_CC_REQUEST_ACCEPT {
			/*
			 * Before event is posted:
			 *   Received CCBSRequest/CCNRRequest response
			 *   Saved CCBSReference
			 */
			Action Relese_LinkID;
			Action Pass_Up_CC_Req_Rsp_Success;
			Action Stop_T_ACTIVATE;
			Next_State CC_STATE_ACTIVATED;
		}
		Stimulus CC_EVENT_CC_REQUEST_FAIL {
			Action Pass_Up_CC_Req_Rsp_Fail(error/reject, code);
			Action Pass_Up_CC_Cancel;
			Action Stop_T_ACTIVATE;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_TIMEOUT_T_ACTIVATE {
			Action Pass_Up_CC_Req_Rsp_Timeout;
			Action Pass_Up_CC_Cancel;
			Action Stop_T_ACTIVATE;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_LINK_CANCEL {
			/* Received CCBSErase */
			/* Claim it was a timeout */
			Action Pass_Up_CC_Req_Rsp_Timeout;
			Action Pass_Up_CC_Cancel;
			Action Stop_T_ACTIVATE;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_CANCEL {
			Next_State CC_STATE_WAIT_DESTRUCTION;
		}
	}
	State CC_STATE_WAIT_DESTRUCTION {
		/* We were in the middle of a cc-request when we were asked to cancel. */
		Epilog {
			Action Stop_T_ACTIVATE;
		}
		Stimulus CC_EVENT_CC_REQUEST_ACCEPT {
			/*
			 * Before event is posted:
			 *   Received CCBSRequest/CCNRRequest response
			 *   Saved CCBSReference
			 */
			Action Send_CC_Deactivate_Req;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_CC_REQUEST_FAIL {
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_TIMEOUT_T_ACTIVATE {
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_LINK_CANCEL {
			/* Received CCBSErase */
			Next_State CC_STATE_IDLE;
		}
	}
	State CC_STATE_ACTIVATED {
		Stimulus CC_EVENT_B_FREE {
			/* Received CCBSBFree */
			Action Pass_Up_B_Free;
		}
		Stimulus CC_EVENT_REMOTE_USER_FREE {
			/* Received CCBSRemoteUserFree */
			Action Pass_Up_Remote_User_Free;
			Next_State CC_STATE_WAIT_CALLBACK;
		}
	}
	State CC_STATE_WAIT_CALLBACK {
		Stimulus CC_EVENT_STOP_ALERTING {
			Action Pass_Up_Stop_Alerting;
			Next_State CC_STATE_ACTIVATED;
		}
		Stimulus CC_EVENT_RECALL {
			/* The original call parameters have already been set. */
			Action Queue_SETUP_Recall;
			Next_State CC_STATE_CALLBACK;
		}
	}
	State CC_STATE_CALLBACK {
		/*
		 * We are waiting for the CC records to be torn down because
		 * CC is complete.
		 * This state is mainly to block CC_EVENT_STOP_ALERTING since
		 * we are the one doing the CC recall so we do not need to stop
		 * alerting.
		 */
	}
	Superstate CC_ACTIVE(CC_STATE_ACTIVATED, CC_STATE_WAIT_CALLBACK, CC_STATE_CALLBACK) {
		Prolog {
			/*
			 * Start T_CCBS2 or T_CCNR2 depending upon CC mode.
			 * For PTMP TE mode these timers are not defined.  However,
			 * we will use them anyway to protect our resources from leaks
			 * caused by the network cable being disconnected.  These
			 * timers should be set much longer than the network
			 * so normally the CC records will be cleaned up by network
			 * activity.
			 */
			Action Start_T_SUPERVISION;
		}
		Epilog {
			Action Stop_T_SUPERVISION;
		}
		Stimulus CC_EVENT_TIMEOUT_T_SUPERVISION {
			Action Send_CC_Deactivate_Req;
			Action Pass_Up_CC_Cancel;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_LINK_CANCEL {
			/* Received CCBSErase */
			Action Pass_Up_CC_Cancel;
			Next_State CC_STATE_IDLE;
		}
		Stimulus CC_EVENT_CANCEL {
			Action Send_CC_Deactivate_Req;
			Next_State CC_STATE_IDLE;
		}
	}
}