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Access Control

11.Access Control

Access Control service is to ensure exclusive access of the services provided by the component. The component grants access to the client which presents with matching session UUID and has the highest authority code. The client becomes the controlling client of the component. Only the command messages from the controlling client are processed.

The Access Control service receives the Session UUID broadcasted from the Platform Control service. If, for some reason, Session UUID is not received from the Platform Control, the Access Control service sends Reject Control messages to the controlling client.

Once granted control, the controlling client needs to repeatably sending Request Control to maintain the control. If Access Control Service did not receive Request Control from the controlling client for a timeout period, Reject Control message is sent to the controlling client. The Reject Control indicates that the client does not have control anymore.

The control can be grabbed by a client with higher authority code than the controlling client. In this case, Reject Control messages is sent to the controlling client as the Confirm Control message is sent to the client with higher authority code.

The controlling client can send Release Control message to the service to indicate that the client does not need to have control anymore. In this case, the Reject Control will also be sent to the controlling client to indicate that Access Control service is not controlled by the client anymore.

Access control is not available when the owning is in Emergency, this is due to the fact that the Management service is in Emergency. In this situation, no control is granted to the new client and the controlling client remains control.

Require: none

Inherit from: none

11.1 Service Behavior

11.1.1 State Diagram


Figure 10 Access Control State Diagram

11.1.2 State Actions


State Actions
AVAIL NO CONTROL
  • Response to Request Control
AVAIL UNDER CONTROL
  • Process command messages from the controlling client
NOT AVAIL NO CONTROL
  • Access control is not available due to the status of the component is at emergency or Session UUID timeout.
NOT AVAIL UNDER CONTROL
  • Access control is not available due to the status of the component is at emergency. The command messages from the controlling client is not processed. However, the controlling client remains in control.

11.1.3 Internal Events


Event Parameters Purpose
ieEmergency emergency = [set | clear] Transition to NOT AVAIL NO CONTROL or NOT AVAIL UNDER CONTROL if set. OR Transition to AVAIL NO CONTRO or AVAIL UNDER CONTROL.
ieShutdown Transition to NOT AVAIL NO CONTROL
ieRenderUseless Transition to NOT AVAIL NO CONTROL
ieReceiveMessage Process messages: Query Control, Request Control, and Release Control.

11.1.4 Transitions


Transition Trigger Condition Action
A Request Control received and its authority code > current authority. Session UUID valid Sender becomes the client of the service. The current authority is to the authority code of the Request Control message.
B Timeout – No Request Control is received within control timeout. Released – Release control is received from the client. Session UUID valid Set current authority to default authority.
C ieEmergency(set) Session UUID valid
D ieEmergency(clear) Session UUID valid
E ieEmergency(set) Session UUID valid
F ieEmergency(clear) Session UUID valid
G Session UUID Invalidate Session UUID and client. Send Reject Control to the controlling client.
G ieShutdow or ieRenderUseless received Invalidate Session UUID and client. Send Reject Control to the controlling client.

11.2 Protocol

11.2.1 Incoming Message Set


# ID Message
1 H:0x00000001
L: 0x0000012A 		Request Control
2 H:0x00000001
L: 0x0000012B 		Release Control
3 H:0x00000001
L: 0x0000012C 		Query Control
4 H:0x00000001
L: 0x00000126 		Set Session Uuid

11.2.2 Outgoing Message Set


# ID Message
1 H:0x00000001
L:0x0000012D 		Confirm Control
2 H:0x00000001
L:0x0000012E 		Reject Control
3 H:0x00000001
L:0x0000012F 		Report Control

11.3 Parameters

  1. CYCLEINTERVAL double, time interval in seconds of each cycle, default=0.1.
  2. DEFAULTAUTHORITY uint8, the lowest authority to obtain control, default=1,
  3. SESSIONTIMEOUT double, timeout in seconds not receiving session id update, default=2.0.
  4. CONTROLTIMEOUT double, timeout in seconds not receiving request control, default=2.0.
  5. CHECKSESSIONINTERVAL double, time interval in seconds to check if session id is not updated, default=0.5.
  6. CHECKCONTROLINTERVAL double, time interval in seconds to check if request control is not received, default=0.5.