Subject: Re: Non-continious network mask support
To: None <tech-net@NetBSD.org>
From: der Mouse <mouse@Rodents.Montreal.QC.CA>
List: tech-net
Date: 12/30/2006 13:46:33
> is there any objection to add code to detect and reject
> non-continious network masks in the route code for all protocol and
> refuse them?

> The feature is not really required as it can be emulated by splitting
> the routes into smaller continious parts,

Except that this can be verbose - extremely verbose in extreme cases.
For example, to route a netmask of 255.254.57.96 under such a
resteriction would require thirty-two routes.  A netmask of 255.255.0.1
would require 32768 routes.  The real question is not "can we emulate
this" but "do enough people still use this to make it worth keeping".

If we do this, I think we either should forbid noncontiguous netmasks
on interfaces or add corresponding code somewhere to do the splitting
you refer to when adding or removing interface routes for interfaces
with noncontiguous netmasks.

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