The idea of writing your own TCP/IP stack may seem overwhelming due to TCP’s complexity over its 30-year lifetime. This blog series aims to educate readers on network and system programming through implementing a minimal userspace TCP/IP stack for Linux. The use of TUN/TAP devices allows for manipulation of L3/L2 traffic, such as tunneling packets. The post delves into the Ethernet Frame Format, Ethernet Frame Parsing, Address Resolution Protocol (ARP), and addresses ARP Algorithm. The ARP implementation is tested with an ARP request, successfully populating the kernel’s ARP cache. The source code for the project is available on GitHub, with future posts focusing on ICMP echo & reply (ping) and IPv4 packet parsing.
https://www.saminiir.com/lets-code-tcp-ip-stack-1-ethernet-arp/