Re: [Openvpn-devel] [PATCH] Workaround FreeBSD 12+ race condition on tun/tap open with IPv6.

[Arne S. <ar...@rf...>]

Am 23.07.20 um 14:19 schrieb Gert Doering:
> On FreeBSD 12 (tested and verified on 12.1-RELEASE-p2), after "ifconfig
> inet6" for a tun/tap interface, there sometimes is a race condition
> where the "IFDISABLED" flag shows up after a short time frame, under
> a second, and never clears itself.  This disables use of the configured
> IPv6 address on the interface, breaking IPv6 over tun/tap operation.
> 
> This only happens if ipv6_activate_all_interfaces="YES" is not
> set in /etc/rc.conf - but there might be reasons why this is not so.
> 
> As a workaround until this can be fixed on the FreeBSD side (or a
> better workaround is found), sleep(1) after ifconfig, then call
> "ifconfig $dev inet6 -ifdisable".
> 
> Yes, this is massively ugly but makes the problem completely go
> away for my test systems.
> 
> (The same effect can be achieved with an --up script that does this,
> but it's even less pretty - see trac ticket)
> 
> FreeBSD: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=248172
> 
> v2: reword text, refer to FreeBSD bug with much more details

Acked-By: Arne Schwabe <ar...@rf...>

This looks like a ugly workaround but if it is the best we can, so be it.

Arne