[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-netdev
Subject:    Re: (usagi-users 00728) Re: [Patch 2of2] IPv6 routers don't join/leave the
From:       "David Stevens" <dlstevens () us ! ibm ! com>
Date:       2001-08-29 7:07:42
[Download RAW message or body]


I think a simple interpretation for the flag is best (for example, "will
forward
packets received on this interface" with the implication from that that you
join
 the all-routers group, set isRouter on NA's, etc.) Forward flag not set
should
be "won't forward packets received, won't set isRouter, etc", but will
still forward
packets received on other intf's to it, IMHO.
     There will always be scenarios that aren't covered-- even overloading
"input and output" breaks at some point and you split forwarding to "input"
and
"output" flags to prevent forwarding in cases like your example, you can
also
 imagine 4 interfaces A, B, C, D where you might want A & B hosts to talk
to each
 other and C & D hosts to talk to each other, but not  A-C, or A-D, B-C or
B-D.
No input/output forwarding flags combination covers that.
     At some point, you need a filter with complex rules for the complex
cases. I would chuck the global flags and just use interface forwarding for
input,
routing table, routing protocols, etc (and a filter, if needed) for output
decisions,
and leave "all" as a convenient shorthand for setting the per-interface
flags.
     In that case, devconf shouldn't be checked, just the interface flag.

                                   +-DLS

[prev in list] [next in list] [prev in thread] [next in thread]