>> 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. You can achieve this in 4 ways: [A] all=1, default=1, AND --> the OLD pre-patch behaviour [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 [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.
