[Winpcap-users] TCP Checksum Calculator

[Guy Harris]

On Mar 5, 2007, at 3:57 AM, Jonathan Hunt wrote:

> I was just wondering whether anyone had implemented a simple TCP  
> checksum-verifying function for a packet captured through WinPcap. I  
> need to include one in a simple C-program which I'm writing, but I'd  
> imagine that it's something which has been coded about 1000 times  
> before, so I thought I'd see if anyone could kindly help me out -  
> there's no point in reinventing the wheel!

There's C code for that in the Wireshark source:

	http://www.wireshark.org/

It's the BSD checksum code.