ControlCommand » History » Revision 21
Revision 20 (Junxiao Shi, 07/14/2014 01:01 AM) → Revision 21/53 (Alex Afanasyev, 07/23/2014 04:15 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 [[ndn-cxx:SignedInterest|Signed Interests]] [Signed Interests](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest) under `ndn:/localhost/nfd` prefix. /localhost/nfd/<management-module>/<command-verb>/................./......................................... \______ _______/ \__________________ ___________________/ \/ \/ ControlParameters Signed Interest additional components 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 [Signed Interest](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest) 7. nonce of [Signed Interest](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest) 8. SignatureInfo of [Signed Interest](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest) 9. SignatureValue of [Signed Interest](http://redmine.named-data.net/projects/ndn-cxx/wiki/SignedInterest) ### ControlParameters ControlParameters block contains arguments to the command. ControlParameters ::= CONTROL-PARAMETERS-TYPE TLV-LENGTH Name? FaceId? Uri? LocalControlFeature? Origin? Cost? Flags? Strategy? ExpirationPeriod? // 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 Origin ::= ORIGIN-TYPE TLV-LENGTH nonNegativeInteger Cost ::= COST-TYPE TLV-LENGTH nonNegativeInteger Flags ::= FLAGS-TYPE TLV-LENGTH nonNegativeInteger Strategy ::= STRATEGY-TYPE TLV-LENGTH Name ExpirationPeriod ::= EXPIRATION-PERIOD-TYPE TLV-LENGTH nonNegativeInteger 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 on 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 arbitrary TLV blocks ### StatusCode StatusCode generally follows HTTP convention \[[RFC2616](http://tools.ietf.org/html/rfc2616#section-10)\]. * Codes between 100 and 399 represents a success. * Codes between 400 and 499 represents a client error. * Codes between 500 and 599 represents a server error. Common codes include: StatusCode | Description -----------|------------------------ 200 | OK 400 | ControlParameters is incorrect 403 | Command Interest is not authorized 404 | Resource (e.g. face, prefix, ...) not found 501 | Module or verb is not supported 503 | Service not available 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 responses. ## TLV-TYPE assignments Type | Assigned value | Assigned value (hex) ------------------------------------------- | ----------------- | -------------------- ControlParameters | 104 | 0x68 FaceId | 105 | 0x69 Uri | 114 | 0x72 LocalControlFeature | 110 | 0x6e Origin | 111 | 0x6f Cost | 106 | 0x6a Flags | 108 | 0x6c Strategy | 107 | 0x6b ExpirationPeriod | 109 | 0x6d ControlResponse | 101 | 0x65 StatusCode | 102 | 0x66 StatusText | 103 | 0x67 These types are assigned from the range reserved for forwarding daemon.