"Alexander V. Chernikov" <melif...@ipfw.ru> wrote in <645741592773...@mail.yandex.ru>:
me> [re-sending email with as non-html] me> me> Hey, me> me> I would like to deprecate net.inet6.ip6.deembed_scopeid sysctl while me> leaving the current default behaviour. me> me> This sysctl controls whether IPv6 scope is embedded in the IPv6 me> address or not when reading or writing route/interface/ifaddr data via me> rtsock/sysctl. me> me> Embedding scope in the address is a hack, that overwrites some of the me> bits that can be used otherwise. It was probably implemented that way me> to simplify route table interactions, as rtable uses this hack to add me> link-local addresses to the same radix tree. me> me> The change to fix the userland api by filling in sin6_scopeid and me> avoid touching IPv6 address was added in r243187, 7 years ago. It me> provided the sysctl in question, allowing to preserve compatibility me> with older applications, by reverting to the old behavior. me> me> 7 years looks like enough timeframe for the applications to be me> adjusted. Unless any major objections arise, I'm going to remove the me> code and make de-embedded IPv6 addresses the only option on July 5 me> 2020. I agree that it is time to remove it and I do not think we need to wait more. This knob was for debugging purpose rather than for keeping compatibility. A concern was that recovering the scopeid might have performance penalty. -- Hiroki
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