On Mon, 13 Nov 2017 14:45:36 +0100
Nicolas Dichtel <[email protected]> wrote:
> The commit a2d3f3e33853 modifies the way to disable dad on an interface.
> Before the patch, setting <iface>.accept_dad to 0 was enough to disable it.
> Because all.accept_dad is set to 1 by default, after the patch, the user
> needs to set both all.accept_dad and <iface>.accept_dad to 0 to disable it.
Perhaps it would make sense to be a bit more descriptive here, this
seems to have generated quite some confusion.
Besides, a2d3f3e33853 was just a fix-up for 35e015e1f577, which is
instead the change which actually changed the behaviour.
What about:
---
With commit 35e015e1f577 ("ipv6: fix net.ipv6.conf.all interface DAD
handlers"), the global 'accept_dad' flag is also taken into account
and set to 1 by default. If either global or per-interface flag is
non-zero, DAD will be enabled on a given interface.
This is not backward compatible: before 35e015e1f577, 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 35e015e1f577:
global per-interface DAD enabled
[default] 1 1 yes
X 0 no
X 1 yes
- After 35e015e1f577:
global per-interface DAD enabled
0 0 no
0 1 yes
1 0 yes
[default] 1 1 yes
- After this fix:
global per-interface DAD enabled
0 0 no
[default] 0 1 yes
1 0 yes
1 1 yes
---
> Fixes: a2d3f3e33853 ("ipv6: fix net.ipv6.conf.all.accept_dad behaviour for
> real")
And I'd rather say:
Fixes: 35e015e1f577 ("ipv6: fix net.ipv6.conf.all interface DAD handlers")
> CC: Stefano Brivio <[email protected]>
> CC: Matteo Croce <[email protected]>
> CC: Erik Kline <[email protected]>
> Signed-off-by: Nicolas Dichtel <[email protected]>
With a more descriptive commit message and the appropriate Fixes:
reference, FWIW,
Acked-by: Stefano Brivio <[email protected]>
--
Stefano
