Date: Fri, 22 Jun 2018 14:08:56 -0400 From: Viktor Dukhovni <freebsd@dukhovni.org> To: freebsd-net@freebsd.org Subject: Re: [PATCH]: The 6to4 stf0 interface flapping in/out of tentative in FreeBSD 11 Message-ID: <D77DB9CD-3197-4963-95AA-CB863E0246B6@dukhovni.org> In-Reply-To: <8fe71247-a9a4-e3cb-3e4a-03852307f080@yandex.ru> References: <CEBB4E6F-4D5F-491F-8C81-C9F81325078B@dukhovni.org> <20171106042248.GL3322@mournblade.imrryr.org> <20180622163812.GA17559@mournblade.imrryr.org> <8fe71247-a9a4-e3cb-3e4a-03852307f080@yandex.ru>
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> On Jun 22, 2018, at 1:41 PM, Andrey V. Elsukov <bu7cher@yandex.ru> =
wrote:
>=20
> Your change looks reasonable due to IPv6 DAD procedure does check for
> presence of IFF_DRV_RUNNING flag. But actually it seems the right
> solution should be disabling DAD for if_stf(4) interface.
> IPv6 DAD requires that given interface should be multicast capable, =
but
> for if_stf(4) it is not true.
> Will it help if you use `ifconfig stf0 inet6 no_dad` before assigning
> IPv6 address?
stf_up() in /etc/rc.d/stf has:
ifconfig stf0 create >/dev/null 2>&1
ifconfig stf0 inet6 =
2002:${ipv4_in_hexformat}:${stf_interface_ipv6_slaid:-0}:${stf_interface_i=
pv6_ifid} \
prefixlen ${stf_prefixlen}
Are you suggesting to add the:
ifconfig stf0 inet6 no_data
right under "ifconfig stf0 create"? I'd have to find a convenient time =
to
reboot to the stock kernel, so this will take O(12 hours) before I can =
re-test.
Perhaps the fix should be belt-and-suspenders? Both set IFF_DRV_RUNNING
and disable DAD automatically for lack of multicast support? Setting
the flag bit might avoid other future issues. Avoiding needless DAD
polling sounds sensible.
--=20
Viktor.
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