Hi,
Thanks for this piece of code - it wonderful. However, I noticed that it appears that the tcp checksum calculation is not correct. I made tcp captures and tcpdump report the checksum is incorrect for TCP. I could not get any server to answer SYN-ACK to this SYN packet (tried with standard sshd and httpd), which confirms that the checksum is wrong. I am doing the research right now and trying to rewrite the checksum part.
Cheers, Alex