ControlCommand » History » Revision 15
Revision 14 (Junxiao Shi, 03/18/2014 11:03 AM) → Revision 15/53 (Alex Afanasyev, 03/27/2014 04:24 PM)
# Control Command **Control Command** is a mechanism of [[Management|NFD Management protocol]]. This document defines the request and response format of commands that can alter forwarder state, and how these commands should be signed and authenticated. This mechanism is useful for altering forwarder state. ## Request format Control commands are signed [[Command Interests]] under `ndn:/localhost/nfd` prefix. /localhost/nfd/<management-module>/<command-verb>/................./............................... \______ \ / \ / ------ _______/ \_____________ ______________/ ------ -------------- -------------- \/ \/ ControlParameters Command Interest security A request Interest has 9 Name components. These components are: 1. "localhost" in UTF-8 2. "nfd" in UTF-8 3. *management-module* in UTF-8, management module to which the command needs to be dispatched 4. *command-verb* in UTF-8, command to be executed 5. *...*, a ControlParameters TLV block 6. timestamp of [[Command Interests]] 7. random-value of [[Command Interests]] 8. SignatureInfo of [[Command Interests]] 9. SignatureValue of [[Command Interests]] ### ControlParameters ControlParameters block contains arguments to the command. ControlParameters ::= CONTROL-PARAMETERS-TYPE TLV-LENGTH Name? FaceId? Uri? LocalControlFeature? Cost? Strategy? // Name is defined in NDN-TLV spec FaceId ::= FACE-ID-TYPE TLV-LENGTH nonNegativeInteger Uri ::= URI-TYPE TLV-LENGTH RFC3986 URI in UTF-8 encoding LocalControlFeature ::= LOCAL-CONTROL-FEATURE-TYPE TLV-LENGTH nonNegativeInteger Cost ::= COST-TYPE TLV-LENGTH nonNegativeInteger Strategy ::= STRATEGY-TYPE TLV-LENGTH Name This definition exhausts all possible fields used in existing commands. Each individual command MUST specify: * a list of required fields: those fields MUST be present * a list of optional fields: those fields MAY be present * the semantics of each required and optional fields A field that is neither required nor optional for a command MUST NOT be present in a ControlParameter given to that command. Each individual command MAY impose additional constraints to certain fields. ## Response format A response from the command interface is a Data that matches the request Interest. The payload of this Data is a ControlResponse block. ControlResponse ::= CONTROL-RESPONSE-TYPE TLV-LENGTH StatusCode StatusText <body>? StatusCode ::= STATUS-CODE-TYPE TLV-LENGTH nonNegativeInteger StatusText ::= STATUS-TEXT-TYPE TLV-LENGTH string in UTF-8 <body> ::= zero or more arbitary TLV blocks ### StatusCode StatusCode generally follows HTTP convention. Codes between 100 and 399 are considered successful; all other codes are considered failure. Common codes include: StatusCode | Description -----------|------------------------ 200 | OK 400 | Arguments are incorrect 403 | Signing key is not authorized for this command 404 | Resource (e.g. face, prefix, ...) not found 501 | Command verb is not supported Each individual command MAY define additional codes. ### \<body> Additional elements are allowed at the end of ControlResponse. Each individual command MAY define the type and meaning of \<body>. Unless otherwise defined by an individual command, \<body> is the ControlParameters passed into this command for all successful responses, and \<body> is empty for all failure response. ## TLV-TYPE assignments Type | Assigned value | Assigned value (hex) ------------------------------------------- | ----------------- | -------------------- ControlParameters | 104 | 0x68 FaceId | 105 | 0x69 Uri | 114 | 0x72 LocalControlFeature | 110 | 0x6e Cost | 106 | 0x6a Strategy | 107 | 0x6b ControlResponse | 101 | 0x65 StatusCode | 102 | 0x66 StatusText | 103 | 0x67 These types are assigned from the range reserved for forwarding daemon.