Implement Telnet LINEMODE Option

[myonara]

Description:
Implement support for the Telnet LINEMODE option to allow the client to specify line-by-line input mode, improving efficiency for text-based applications. This option is especially useful for applications where data is processed as complete lines rather than character-by-character.

Details:

1. Option Code: 34

2. Functionality:

   • When LINEMODE is negotiated, the server allows the client to handle input locally, sending entire lines only after the user presses Enter.
   • LINEMODE includes several suboptions that allow for further customization:
     • MODE: Specifies whether to operate in line or character mode.
     • EDIT: Allows basic local editing, such as handling backspaces.
     • TRAPSIG: Allows the client to manage signal commands locally (e.g., interrupt or quit) before sending them to the server.
     • SLC (Special Line Characters): Defines specific characters for functions like interrupt, EOF, or suspend.

3. Expected Workflow:

   • The client responds to IAC DO LINEMODE from the server with IAC WILL LINEMODE.
   • The server may then send specific LINEMODE suboptions, to which the client should respond appropriately.
   • The client should support common suboptions like MODE, EDIT, and TRAPSIG for basic line editing and control.

4. Acceptance Criteria:

   • The client successfully negotiates LINEMODE with the server.
   • The client properly handles and responds to LINEMODE suboptions.
   • Input is processed in line mode after negotiation, sending data only after the user completes each line.

References:

• Telnet RFC 1184 (for LINEMODE negotiation and suboptions)