ControlCommand » History » Revision 3
Revision 2 (Junxiao Shi, 01/23/2014 08:54 PM) → Revision 3/53 (Junxiao Shi, 01/23/2014 11:36 PM)
# 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` prefix.
A request Interest has at least four Name components.
The first four components are:
1. "localhost" in UTF-8
2. "nfd" in UTF-8
3. *verb*, the command verb in UTF-8
4. *options*, the arguments to the command
### 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 seven Name components.
Certain commands that do not change the forwarder state do not require a signature.
An unsigned request Interest has four 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
...
StatusCode ::= STATUS-CODE-TYPE TLV-LENGTH
nonNegativeInteger
StatusText ::= STATUS-TEXT TLV-LENGTH
string in UTF-8
**StatusCode** generally follows HTTP convention. Common codes include:
StatusCode | Description
-----------|------------------------
200 | OK
400 | Arguments are incorrect
401 | Signed request is required for command, but unsigned request is passed
403 | Signing key is not authorized for this command
404 | Command verb is not supported
Additional elements are allowed at the end of **ControlResponse**.
Each individual command specification defines whether and what can present.
## TLV-TYPE assignments
Type | Assigned value | Assigned value (hex)
------------------------------------------- | ----------------- | --------------------
ControlResponse StatusResponse | 130 | 0x82
StatusCode | 139 | 0x8b
StatusText | 140 | 0x8c