[e2e] UDP length field

Mikael Degermark micke at CS.Arizona.EDU
Thu Apr 19 09:32:02 PDT 2001

Hi Greg,

You are right that the UDP module gets the IP length from the 
IP module. However, that is not the length that is used 
in the UDP pseudo header. All UDP implementations we've looked
at take the pseudo header length information from the 
UDP header. I.e., they do NOT derive it from the IP length.

The validity checks is another issue, all UDPs that we've 
looked at seems to adhere to Craigs rules. There is one 
exception which is Quake's home-grown UDP. They do some
strange things, but as they never communicate with anything
else than other Quakes, that is not much of a problem.



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