Skip site navigation (1)Skip section navigation (2)
Date:      Thu, 15 Aug 2002 00:12:58 -0700
From:      Terry Lambert <tlambert2@mindspring.com>
To:        Luigi Rizzo <rizzo@icir.org>
Cc:        ipfw@freebsd.org
Subject:   Re: RFC: new mbuf flag bit needed
Message-ID:  <3D5B547A.E29F61BA@mindspring.com>
References:  <20020815000720.B24495@iguana.icir.org>

next in thread | previous in thread | raw e-mail | index | archive | help
Luigi Rizzo wrote:
> ipfw does this using two specific hacks:
>   + ICMP packets will not generate a response even on "unreach" rules;
>   + TCP packets with the RST bit set will not generate a response
>     on "unreach" rules)
> 
> ipfw2 has a harder time because keepalives have nothing very
> distinguishable in them (except sequence numbers which refer to old
> data; but to detect them requests a lookup of the stateful entry).

Why does ipfw2 not do it exactly the way ipfw does it?  I don't
understand why it has a harder time, since it has all the same
information.


> So my proposal is to use a different method, and use one of the
> m_pkthdr.flags bits as a marker that the packet should bypass the
> firewall. I can restrict the change to just ip_fw2.c so no other
> parts of the system will need to be modified, except sys/mbuf.h for
> the definition of the new bit if we want to give it a meaningful name.

Ugh.  So all you have to really do is figure a way to force
this bit to get set in data, and you can bypass the firewall
with all you hack packets?


-- Terry

To Unsubscribe: send mail to majordomo@FreeBSD.org
with "unsubscribe freebsd-ipfw" in the body of the message




Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?3D5B547A.E29F61BA>