Re: generalized packet modification (inc tcpflags, adding options)

[Patrick McHardy <kaber@trash.net>]

Hi Don,

Don Cohen wrote:

>It's not immediately clear to me what language would be best for 
>describing such modifications and that would probably be worth
>discussing on this list.  For that matter, it's not clear what
>language is best for describing the match.  My u32 language was
>designed to do what seems to be needed for IPv4 but is not good
>for IPv6.  I recall someone (Patrick?) supplied a BPF analog of the
>u32 match.  (Where can I find that, BTW?)  Is that language capable of
>specifying data modification?  Of course other important issues
>include run time efficiency and convenience for the user.
>

I never made that match. It was just an idea which came up while hacking
ppp-filters for isdn, but i let it be because of the fixed-size match 
data problem.
However, BPF is only for specifying filter expressions, not for mangling 
data.

Bye,
Patrick