checksum in raw sockets and pcap [closed]

Posted by hero on Stack Overflow See other posts from Stack Overflow or by hero
Published on 2010-03-22T06:26:54Z Indexed on 2010/03/22 6:31 UTC
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pcap

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tcp

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raw-sockets

i am using pcap library to sniff some packets, change their tcp data , and then inject my packet on the network.
my question is: if i changed in the tcp data, should i recalculate the length field in the tcp header? should i also change the checksum? i read in a page on how to create raw sockets that if you set the tcp_checksum to 0, the kernel will automatically calculate it and fill it, is this true for windows machines also?

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