On Thu, May 29, 2014 at 3:32 PM, Andreas Nilsson <[email protected]> wrote:
> On Thu, May 29, 2014 at 3:10 PM, Luigi Rizzo <[email protected]> wrote: > >> On Thu, May 29, 2014 at 08:45:26PM +0800, bycn82 wrote: >> ... >> > >> > Sure, that is the reason why developers are providing more and more >> rule options. But the my question is do we have enough options to match all >> the fixed position values? >> >> we do not have an option for fixed position matching. >> >> As i said, feel free to submit one and i will be happy to >> import it if the code is clean (btw i am still waiting >> for fixes to the other 'rate limiting' option you sent), >> but keep in mind that 'fixed position' is mostly useless. >> >> More useful options would be one where you express the position as >> >> '{MAC|VLAN|IP|UDP|TCP|...|PAYLOAD}+offset' >> >> so at least you can adapt to variant headers, or one where you can look >> for a pattern in the entire packet or in a portion of it. >> >> cheers >> luigi >> _______________________________________________ >> [email protected] mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-net >> To unsubscribe, send any mail to "[email protected]" >> > > Wouldn't PAYLOAD require possibly reassembly of a fragmented packet? > well, other firewalls do reassemble fragments, ipfw does not (actually there was some code floating around in the past that did implement a reassembly, not sure if it was committed). With this in mind, PAYLOAD would not be that different from TCP if you think that you can have a ton of IPV6 headers and extensions. So if/when we implement reassembly, that would be the default for any action that searches past the end of the first fragment. Except from fragmentation, all ipfw instructions already track the beginning of the relevant header for the info at hand (typically skipping ip options or ipv6 headers). It costs something, but not a fortune. cheers luigi > It certainly is a good feature, don't get me wrong. But what are the > performance hits? > > Best regards > Andreas > -- -----------------------------------------+------------------------------- Prof. Luigi RIZZO, [email protected] . Dip. di Ing. dell'Informazione http://www.iet.unipi.it/~luigi/ . Universita` di Pisa TEL +39-050-2211611 . via Diotisalvi 2 Mobile +39-338-6809875 . 56122 PISA (Italy) -----------------------------------------+------------------------------- _______________________________________________ [email protected] mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[email protected]"
