Le 13/11/2017 à 16:05, Stefano Brivio a écrit : > On Mon, 13 Nov 2017 23:52:26 +0900 > Maciej Żenczykowski <m...@google.com> wrote: > >>>> Should we consider rolling back the patch that caused this? >>>> "accept_dad = 1" is the proper IETF-expected default behaviour. >>>> >>>> Alternatively, if we really want to make all, default, and ifname >>>> useful perhaps we need to investigate a tristate option (for currently >>>> boolean values, at least). -1 could mean no preference, for example. >>> >>> I haven't checked how ugly it would be, yet. But another way to restore >>> the previous behaviour, while keeping the new functionality, would be >>> to keep the global default as 1 and instead set the per-interface >>> accept_dad default value to 0. What do you think? >> >> The default out-of-the-box behaviour should definitely be to do DAD. Yes, and my patch didn't modify this.
>> >> You can achieve this in 4 ways: >> >> [A] all=1, default=1, AND --> the OLD pre-patch behaviour > > Old pre-patch behaviour simply ignored the 'all' value though. > >> [B] all=1, default=1, OR --> the NEW post-patch behaviour - problematic >> [C] all=1, default=0, OR --> problematic for same reason: iface=0 is a no-op > > But this way you could still globally disable DAD, starting from > default values, by simply setting 'all' to zero, which is what Nicolas > wanted. > >> [D] all=0, default=1, OR >> >> Note that: >> AND == (all < 1 || interface < 1) >> OR == (all < 1 && interface < 1) >> >> [C] requires one to set all but one interface (incl. default) to 1, >> then set all=0, >> just to disable a single interface's dad >> >> [D] is weird, because with the default already being dad enabled, there's >> really >> no reason to ever set all=1 >> >> Being able to disable either for all interfaces (via all=0) or for a >> specific interface (via iface=0) seems >> the most useful. >> >> Setting all=1, default=0, specific_interfaces=1, AND-logic also seems useful. >> >> Hence my vote to rollback a2d3f3e33853. > > We're mostly talking about 35e015e1f577 here. > I don't have a strong opinion about what to do. My reasoning was that before patch 35e015e1f577, all.accept_dad had no effect, thus I took the assumption that users didn't modify it, but only default.accept_dad and <iface>.accept_dad. With this assumption, my patch helps to keep the same settings when upgrading the kernel. Nicolas
