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From: Scott MacKay <scottmackay@yahoo.com>
To: Netfilter Mailing List <netfilter@lists.netfilter.org>
Subject: Bridge + mangling; any similar experiences?
Date: Tue, 15 Apr 2003 05:04:37 -0700 (PDT)	[thread overview]
Message-ID: <20030415120437.69926.qmail@web13904.mail.yahoo.com> (raw)
In-Reply-To: <1050401128.1440.37.camel@raylinux.internal>

Hiyas, sorry to bother this list, but the ebtables
mailing list is kinda quiet (plus the bridge feature I
think is integrated into 2.5 kernel...).

I have been having a problem, and was wondering if
anyone had similar experiences.  I am using 2.4.20;
RedHat distro + recompiled kernel with the latest
ebtables + br thing patch.  The sole, only, and
probably ever only reason is so I can be in bridge
mode and have prerouting & postrouting hooks (so if a
non-ebtables approach is known, please let me know).

I have a custom userspace module which I am using to
mangle packets.  I mangle the contents of TCP/UDP
payloads, recalcing the IP and TCP/UDP headers.  I
basically mangle the packets between 2 bridge boxes,
demangling packets on each side's 'intranet'.  No
firewall denial rules or nothing; just the pre/post
routing.  When I do not mangle (just pass in/out my
userspace), it works fine.  When I reconfigure in a
router mode (as opposed to bridge), my mangling works
fine.  In bridge mode, though, with mangling, by
traffic crawls to tens of bytes/second.  If I turn off
the mangling, it picks back up to happy 10mbit rates.
The payload, when finally delivered (in my testing, I
use a simple TCP push/receive pair of applications),
is valid, so it does  mangle/demangle OK.  

Does anyone have any ideas why this could be
happening?  
Any pointers, thoughts on the
netfilter/ebtables/whatever would help me greatly. 
Thanks!!!

-Scott



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  reply	other threads:[~2003-04-15 12:04 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-04-15  9:52 Understanding the Forward and Postrouting chain Chris Partsenidis
2003-04-15 10:05 ` Raymond Leach
2003-04-15 12:04   ` Scott MacKay [this message]
2003-04-15 13:23 ` Joel Newkirk

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