Level-IP is a Linux userspace TCP/IP stack, implemented with TUN/TAP devices.

The main goals are to:

• Learn TCP/IP
• Learn Linux systems/network programming
• Learn Linux Socket API

The results of the learning experience will be accompanied by explanatory blog posts:

• Part 1, Ethernet & ARP: http://www.saminiir.com/lets-code-tcp-ip-stack-1-ethernet-arp
• Part 2, IPv4 & ICMPv4: http://www.saminiir.com/lets-code-tcp-ip-stack-2-ipv4-icmpv4
• Part 3, TCP Basics & Handshake: http://www.saminiir.com/lets-code-tcp-ip-stack-3-tcp-handshake/
• Part 4, TCP Data Flow & Socket API: http://www.saminiir.com/lets-code-tcp-ip-stack-4-tcp-data-flow-socket-api/
• Part 5, TCP Retransmission: http://www.saminiir.com/lets-code-tcp-ip-stack-5-tcp-retransmission/

See Getting Started.

For development documentation, start with Development.

Reference works

• Linux kernel TCP/IP stack, source code
• picoTCP, source code
• Xiaochen Wang's TCP/IP stack, source code

License

See LICENSE.md (MIT)