EMNet: A Go TCP Server with Dynamic Port Selection and Peer Management

• this project is experimental

Overview

EMNet is a Go server program that starts a TCP server based on command-line arguments or defaults, and it manages peer IPs using a global map. The server handles two types of JSON messages: ADD_PEER and ASK_IP.

Features

1. Dynamic Port Selection:

   • If both IP and port are specified, the server starts on the given IP and port.
   • If only the IP is specified, the server starts on the first available port between 80 and 60000.
   • If no arguments are provided, the server starts on 0.0.0.0 and the first available port between 80 and 60000.

2. Peer Management:

   • ADD_PEER: Adds a peer IP to the global map with a generated random key.
   • ASK_IP: Retrieves and removes a peer IP from the global map based on a given key.

Usage

Command-Line Arguments

The server can be started with the following command-line arguments:

• -ip IPV4 (Optional): IP address to bind the server.
• -port PORT (Optional): Port to bind the server.

Examples

1. Start server on a specified IP and port:

   ./EMNet -ip 192.168.1.10 -port 8080

2. Start server on a specified IP with dynamic port selection:

   ./EMNet -ip 192.168.1.10

3. Start server with default IP (0.0.0.0) and dynamic port selection:

   ./EMNet

JSON Message Handling

The server processes JSON messages sent by clients. The messages should be enclosed in {}. The following message types are supported:

1. ADD_PEER:

   • Request:

     {
         "msg": "ADD_PEER",
         "IP_Peer": "192.168.1.20:63413"
     }

   • Response (Success):

     {
         "msg": "SUCCESS",
         "id": 123456
     }

   • Response (Failure):

     {
         "msg": "FAILED"
     }

2. ASK_IP:

   • Request:

     {
         "msg": "ASK_IP",
         "id": 123456
     }

   • Response (Success):

     {
         "msg": "SUCCESS",
         "IP": "192.168.1.20:34721"
     }

   • Response (Failure):

     {
         "msg": "FAILED"
     }

Building and Running EMNet

Building

To build the server, navigate to the directory containing the code and run:

go build -o EMNet

Running

To run the server, use one of the following commands based on your requirements:

1. With specified IP and port:

   ./EMNet -ip 192.168.1.10 -port 8080

2. With specified IP and dynamic port:

   ./EMNet -ip 192.168.1.10

3. With default IP and dynamic port:

   ./EMNet

Contributing

Contributions are welcome! Please fork the repository and submit a pull request for any improvements or bug fixes.

License

This project is licensed under the MIT License. See the LICENSE file for details.