NFD Control Command specification¶

NFD management module exposes a command interface as Interest-Data exchange.
Commands provided over this interface are useful for querying or changing the state of NFD forwarder.

Request format¶

A request to the command interface is an Interest under ndn:/localhost/nfd/<management-module>/<command-verb>/... prefix.

 /localhost/nfd/<management-module>/<command-verb>/................./...............................
                                                   \               / \                             /
                                                    ------  ------    -------------- --------------
                                                          \/                       \/
                                               Control Command options    Control Interest security
                                                     (optional)                info (optional)

A request Interest has at least five Name components.
The first five 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. ..., the arguments to the command, defined for each management module in separate specifications:

- [[FibMgmt|FIB Management specification]]
- [[FaceMgmt|Face Management specification]]

Signed request and Unsigned request¶

Most commands require a signature to be included in the Name.
The signature format is defined in Signed Interests spec.
A signed request Interest has eight Name components.

Certain commands that do not change the forwarder state do not require a signature.
An unsigned request Interest has five Name components.

Each individual command specification defines whether a request Interest using that command verb should be signed or not.

Options¶

The option component contains arguments to the command as a TLV.

This component is required even if the command verb does not need any arguments.
In that case, this component would have zero length.

Each individual command specification defines the format of the options TLV.
The TLV-TYPE numbers used in this TLV should be allocated from application range, and are not required to be unique across different command verbs.

Response format¶

A response from the command interface is a Data that matches the request Interest.
The payload in this Data should be a ControlCommandResponse element.

ControlResponse ::= CONTROL-RESPONSE-TYPE TLV-LENGTH
                      StatusCode
                      StatusText
                      <StatusBody>?

StatusCode      ::= STATUS-CODE-TYPE TLV-LENGTH
                      nonNegativeInteger

StatusText      ::= STATUS-TEXT TLV-LENGTH
                      string in UTF-8

<StatusBody>    ::= <TLV block defined by the specific control protocol>

StatusCode generally follows HTTP convention. Common codes include:

Additional elements are allowed at the end of ControlResponse.
Each individual command specification defines whether and what can present.

TLV-TYPE assignments¶

(Types are assigned from the range reserved for forwarding daemon.)