Re: ipv6_enable

Doug Barton <dougb_at_FreeBSD.org> wrote
  in <4BB95564.1070604_at_FreeBSD.org>:

do> On 04/04/10 02:41, Hiroki Sato wrote:
do> > "Kevin Oberman" <oberman_at_es.net> wrote
do> >   in <20100404053352.E6F751CC13_at_ptavv.es.net>:
do> >
do> > ob> The use of FACILITY_enable in rc.conf predates /etc/rc.d scripts and I
do> > ob> see no reason not to use them to enable or disable functionality whether
do> > ob> it involves a script in rc.d or not. The idea is to have a clear,
do> > ob> obvious way to enable or disable functionality. I see nothing in Hiroki's
do> > ob> proposal that is nearly as clear and to the point as 'ipv6_enable'.
do> >
do> >  Another reason I lean to not using xxx_enable is that an rc.d knob
do> >  cannot control enabling/disabling the IPv6 functionality actually.
do> >  It was true even when we were using the network_ipv6 script.
do>
do> But that's equally true of how you're using ipv6_prefer. :)  You've
do> basically just moved the overloading of 2 of the 3 previous functions of
do> ipv6_enable to ipv6_prefer. I am suggesting that we split all 3
do> functions into different knobs.

 No, the current ipv6_prefer=NO has nothing to do with disabling IPv6.
 It is just related to source address selection and a seatbelt for
 IPv4-only people.  I do not think I just moved the old functions.

 Let me explain how these changes happened.  As I explained earlier, I
 added $ipv6_prefer to *enable IPv6 by default*.  IPv6 needs some
 configuration even if you do not use IPv4 when the kernel supports
 it, and skipping all of IPv6 configuration in the old
 rc.d/network_ipv6 script caused another problems.  So, I thought it
 was possible to enable IPv6 by default and initialize the
 functionality with reasonable default parameters.  This parameters
 included "disable ACCEPT_RTADV by default", which is one of the
 topics we are discussing now.

 After I moved the initialization outside of the $ipv6_enable, then I
 noticed that the rest which should be inside of the $ipv6_enable is
 IPv6 GUA address assignments and routing settings only.  Here I
 stepped further; I changed the disabling feature of $ipv6_enable into
 "whether an IPv6 address is assigned or not".  That was the whole
 story.

 The old rc.d/network_ipv6 had a lot more for IPv6 configuration in
 the $ipv6_enable conditional clause and ipv6_enable=NO meant to
 disable them, too.  This is a big difference.  The new ipv6_enable in
 your patch is not the same in this regard.

 Well, I can understand and agree that people want a handy knob to
 disable IPv6.  I think it is more constructive for this discussion to
 be more specific what should be disabled, then.  I am still not sure
 what you and other people mean by "disable IPv6".

 My opinion is "ipv6_enable=NO" should mean disabling IPv6
 functionality completely.  I do not want to call a knob just to
 ignore ifconfig_IF_ipv6 lines as "ipv6_enable" as well as do not want
 to disable IPv6 functionality completely by default.  So I am
 interested in what people want more precisely.

-- Hiroki