Downright impressive. I'm implementing the TCP/IP stack for my OS at the moment, and it's sitting at about 400 lines before TCP (ethernet, IP, DHCP, and ARP). Definitely going to see how I can improve it after this.
That's impressive. Are you writing your OS for study purposes or you have something special in mind? I am interested in knowing as I am planning to do the same and might want to consult you.
Just something that's interested me for years. Might eventually become a part of some commercial embedded devices I've planned, but that's a long way out.