TCP No Block Connect Test

TCP No Block Connect Test

Overview

This application demonstrates the difference between blocking and non-blocking TCP connections using NetBurner embedded networking hardware. The program provides an interactive menu system that allows users to test both standard blocking connect() calls and non-blocking NoBlockConnect() calls.

Purpose

The standard TCP connect call will block until the connection is either made or fails. The non-blocking connect call will initiate a TCP connection and return immediately, allowing the application to continue processing while the connection is established in the background.

Features

• Interactive menu-driven interface
• Support for both blocking and non-blocking TCP connections
• Real-time connection state monitoring
• Automatic periodic data transmission (every 5 seconds)
• User input forwarding over established connections
• Configurable destination IP address and port

Menu Options

The application provides the following commands:

• C - Make a connection using standard blocking connect()
• N - Make a connection using non-blocking NoBlockConnect()
• X - Close the current connection
• I - Specify the destination IP address and port number
• Any other character - Send the character over the TCP connection (if established)

How It Works

Blocking Connection (C command)

1. Prompts for destination IP and port if not already set
2. Calls connect() which blocks until connection succeeds or fails
3. Immediately reports success or failure
4. Connection is ready for data transmission upon success

Non-Blocking Connection (N command)

1. Prompts for destination IP and port if not already set
2. Calls NoBlockConnect() which returns immediately
3. Reports "Connect started" if the call succeeds
4. Continuously monitors connection state using TcpGetSocketState()
5. Reports "NoBlock connection is done" when TCP_STATE_ESTABLISHED is reached

Automatic Features

• Sends a timestamp message every 5 seconds over established connections
• Displays current TCP state during non-blocking connection attempts
• Forwards any typed characters to the remote host when connected

Technical Details

• Key APIs Used:
  • connect() - Standard blocking TCP connection
  • NoBlockConnect() - Non-blocking TCP connection initiation
  • TcpGetSocketState() - Connection state monitoring
  • Standard socket operations (write(), close())

Build Requirements

• NetBurner development environment
• NetBurner hardware platform
• Standard NetBurner libraries (tcp.h, utils.h, iosys.h, etc.)

Usage Example

1. Run the application on NetBurner hardware
2. When prompted, enter the destination IP address
3. Enter the destination port number
4. Use menu commands to test different connection methods:
   • Try 'C' for blocking connection
   • Try 'N' for non-blocking connection
   • Use 'X' to close connections
   • Use 'I' to change destination settings
5. Type any characters to send data over established connections

Connection State Monitoring

For non-blocking connections, the application continuously displays the TCP state:

• State values correspond to standard TCP states
• Connection is ready when TCP_STATE_ESTABLISHED is reached
• Failed connections will show appropriate error states

Notes

• Only one connection can be active at a time
• IP address and port cannot be changed while connected
• System diagnostics are enabled for debugging (should be disabled in production)
• The application runs in an infinite loop until manually terminated