----- Original Message -----
From: "Lennert Buytenhek" <[EMAIL PROTECTED]>
To: "Bart De Schuymer" <[EMAIL PROTECTED]>
Cc: <[EMAIL PROTECTED]>
Sent: Monday, December 24, 2001 2:44 PM
Subject: Re: [Bridge] [PATCH] bridge-nf-0.0.4.bis patch available


> Hi there,

Hello,

> Could you send patches in smaller bits please?  In this case especially
since
> some parts are obvious and some parts aren't..

Will do.

> > - Give bridge netfilter functions priority NF_BR_PRI_LAST (i.e. INT_MAX)
>
> Why is this, I guess because of your ebtables hooks?  I'd rather hand out
> priorities properly (i.e. NF_BR_FILTER, NF_BR_IP_PASSTHROUGH in
> netfilter_bridge.h) instead of having more magic numbers in here..

Ok, but my main point was that the nf bridge priority of passthrough should
be INT_MAX, no matter what name you give it.
Any function that attaches to a netfilter hook after the passthrough
function might as well attach before the passthrough function:
- if the function does stuff for ip packets it gets useless if it attaches
after the passthrough function because passthrough steals those packets.
- in the other case it doesn't matter whether the function is executed
before the passthrough function or not, because passthrough couldn't care
less about non-ipv4 packets.
Ok, theoretically there could be a function that only wants to look at the
ip packets if the passthrough function is not loaded. Then that function
needs to have a lower priority (and thus a higher number) than the
passthrough function.
I just find 0 as priority to be such a low value. Basically you are
confining most functions to negative priority values... Maybe (INT_MAX - 1)
or so :-)

> > - Give sabotage functions netfilter priority NF_IP_PRI_FIRST (i.e.
INT_MIN),
> > except for NF_IP_LOCAL_OUT ofcourse
>
> For PRE_ROUTING I agree, for FORWARD not really.  There just happens to be
> nothing before PRI_BRIDGE_SABOTAGE, but I'm sure there could be hooks
> interested in the 'original' (i.e. possibly un'flooded') packet.

Ok, but naming that priority also NF_IP_PRI_BRIDGE_SABOTAGE is misleading.
In essence I believe the priorities for SABOTAGE on NF_IP_LOCAL_OUT and
NF_IP_FORWARD are unrelated. It just happens that that value (-50) works for
both hooks. Couldn't we put something like (INT_MIN + 10)?
Suppose someone has an ip netfilter function and decides to put it at
priority value -60 (not knowing about passthrough). It would be most likely
better that the passthrough priority value be lower than this -60.

cheers,
Bart

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