Re: [PATCH net v2] ipv6: set all.accept_dad to 0 by default

[Stefano Brivio <sbrivio@redhat.com>]

On Tue, 14 Nov 2017 14:21:32 +0100
Nicolas Dichtel <nicolas.dichtel@6wind.com> wrote:

> With commits 35e015e1f577 and a2d3f3e33853, the global 'accept_dad' flag
> is also taken into account (default value is 1). If either global or
> per-interface flag is non-zero, DAD will be enabled on a given interface.
> 
> This is not backward compatible: before those patches, the user could
> disable DAD just by setting the per-interface flag to 0. Now, the
> user instead needs to set both flags to 0 to actually disable DAD.
> 
> Restore the previous behaviour by setting the default for the global
> 'accept_dad' flag to 0. This way, DAD is still enabled by default,
> as per-interface flags are set to 1 on device creation, but setting
> them to 0 is enough to disable DAD on a given interface.
> 
> - Before 35e015e1f57a7 and a2d3f3e33853:
>           global    per-interface    DAD enabled
> [default]   1             1              yes
>             X             0              no
>             X             1              yes
> 
> - After 35e015e1f577 and a2d3f3e33853:
>           global    per-interface    DAD enabled
> [default]   1             1              yes
>             0             0              no
>             0             1              yes
>             1             0              yes
> 
> - After this fix:
>           global    per-interface    DAD enabled
>             1             1              yes
>             0             0              no
> [default]   0             1              yes
>             1             0              yes
> 
> Fixes: 35e015e1f577 ("ipv6: fix net.ipv6.conf.all interface DAD handlers")
> Fixes: a2d3f3e33853 ("ipv6: fix net.ipv6.conf.all.accept_dad behaviour for real")
> CC: Stefano Brivio <sbrivio@redhat.com>
> CC: Matteo Croce <mcroce@redhat.com>
> CC: Erik Kline <ek@google.com>
> Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Acked-by: Stefano Brivio <sbrivio@redhat.com>

-- 
Stefano