ControlCommand » History » Revision 28
Revision 27 (Junxiao Shi, 12/24/2016 07:22 PM) → Revision 28/53 (Davide Pesavento, 02/13/2017 11:57 AM)
# Control Command **Control Command** is a mechanism of [[Management|NFD Management protocol]]. This mechanism is useful for altering the state of the forwarder. This document defines the request and response format of such commands, commands that can alter forwarder state, and how they these commands should be signed and authenticated. This mechanism is useful for altering forwarder state. ## Request format Control commands are [[ndn-cxx:CommandInterest|Command Interests]] under a NFD management prefix. The Name for a request Interest has the following form: /<prefix>/<management-module>/<command-verb>/<control-parameters>/<command-interest-components> * *prefix* is a NFD management prefix. Unless otherwise noted, all commands use `/localhost/nfd` prefix. Each individual command MAY specify additional prefixes under which that command could be accepted. * *management-module* is the name of management module to which the command needs to be dispatched. * *command-verb* is the command to be executed. * *control-parameters* is a ControlParameters TLV block wrapped in a NameComponent. * *command-interest-components* are four additional components defined by [[ndn-cxx:CommandInterest|Command Interest]] spec. ### ControlParameters ControlParameters block contains arguments to the command. ControlParameters ::= CONTROL-PARAMETERS-TYPE TLV-LENGTH Name? FaceId? Uri? Origin? Cost? Flags? Mask? Strategy? ExpirationPeriod? FacePersistency? ; Name is defined in NDN packet format specification FaceId ::= FACE-ID-TYPE TLV-LENGTH nonNegativeInteger Uri ::= URI-TYPE TLV-LENGTH RFC3986 URI in UTF-8 encoding Origin ::= ORIGIN-TYPE TLV-LENGTH nonNegativeInteger Cost ::= COST-TYPE TLV-LENGTH nonNegativeInteger Flags ::= FLAGS-TYPE TLV-LENGTH nonNegativeInteger Mask ::= MASK-TYPE TLV-LENGTH nonNegativeInteger Strategy ::= STRATEGY-TYPE TLV-LENGTH Name ExpirationPeriod ::= EXPIRATION-PERIOD-TYPE TLV-LENGTH nonNegativeInteger ; FacePersistency is defined in FaceMgmt section 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 field 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 loosely generally follows the HTTP semantics described in [RFC 7231](https://tools.ietf.org/html/rfc7231#section-6). convention [RFC2616](http://tools.ietf.org/html/rfc2616#section-10). * Codes between 100 and 399 represent represents a success. * Codes between 400 and 499 represent represents a client error. * Codes between 500 and 599 represent 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., (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 Origin | 111 | 0x6f Cost | 106 | 0x6a Flags | 108 | 0x6c Mask | 112 | 0x70 Strategy | 107 | 0x6b ExpirationPeriod | 109 | 0x6d ControlResponse | 101 | 0x65 StatusCode | 102 | 0x66 StatusText | 103 | 0x67 (reserved, formerly LocalControlFeature) | 110 | 0x6e