[Winpcap-users] TCP Checksum Calculator

Guy Harris guy at alum.mit.edu
Tue Mar 6 05:38:27 GMT 2007

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:


It's the BSD checksum code.

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