CheckIPHeader vs bootp/dhcp

[Eddie Kohler]

> Hi,
> I was trying to use dhcp with a click router but CheckIPHeader was rejecting 
> dhcp discover packets since they have a source addr of 0.0.0.0.

Hi John,

I finally changed CheckIPHeader to work correctly. It now has both a list
of bad sources, and a list of good destinations. A packet with a bad source
is not dropped if it is destined for a good destination.

The easiest way to specify bad source addresses now is via the INTERFACES
keyword argument. This holds a list of the router's interface addresses and
prefixes. For example:

	CheckIPHeader(INTERFACES 18.26.4.1/24 1.0.0.1/8)

acts the same as

	CheckIPHeader(BADSRC 0.0.0.0 255.255.255.255 18.26.4.255 1.255.255.255,
		      GOODDST 18.26.4.1 1.0.0.1)

CheckIPHeader2 and IPInputCombo have also been changed to have the right
semantics.

Thanks for reporting this!
Eddie