📣 echoman: simple echo server

🌱　Overview

• This is a simple tool where a client generates packets over TCP/IP and sends them to a server.
• The echo server echoes data by swapping src/dst L3 address and L4 port number. (However, some parameters such as TypeCode and CheckSum are recalculated.)

✏️ Documents

• Information: Network design
• Application: An application that communicates over the overlay network
• Usage: How to start echoman
• Appendix: About sockets

📚 References

• RFC 792 - Internet Control Message Protocol
• RFC 768 - User Datagram Protocol
• Universal TUN/TAP device driver
• Checksum calculation