Re: testing checksum in helpers is redundant with tcp_window_tracking

[netfilter@interlinx.bc.ca]

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On Fri, Feb 28, 2003 at 11:33:15AM +0100, Jozsef Kadlecsik wrote:
> 
> No, I think that is a bad idea. The tcp-window-tracking patch patches the
> default helpers (ftp, irc) and remove the redundant checkings.

Right.  I have noticed this.  But based on that idea, it should patch
all of the helpers, but that becomes a maintenance nightmare.

> However the
> current status of the patch is 'extra'.

Right.  I understand that.

> No other
> subsystem/patch should be made dependent of it.

If it were a requirement type of dependancy, I would completely agree
with you, but I am talking about an optional "take advantage of it if
it's there and business as usual if it's not" type dependency.

Adding a macro to tcp-window-tracking (simply signifying it's in the
kernel) and wrapping the tcp checks in helpers with a test for the
macro does not introduce any loss of functionality at all.  A module
writer doesn't even have to use it if he doesn't want to, but if he
wants his module to be as efficient as possible in the presence of
tcp-window-tracking, he can use the macro.

b.

-- 
Brian J. Murrell

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