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Re: dhcpcd, carrier and RTM_INFO

On Sun, 05 Feb 2012 13:56:14 -0500, Greg Troxel wrote:
My impression is that historically (as in 2.8BSD, 4.1BSD) IFF_RUNNING
meant "resources are allocated" and it has never had anything to do with link state. Paying attention to IFM_ACTIVE (and ignoring IFF_RUNNING)
seems like the right thing.

That's good to know.
I've adjusted dhcpcd in my git tree accordingly.

Interface up and down and valid link are separate issues; I don't see
how they should be commingled.

Well, a valid link but with the interface marked as down I treat it as carrier down in dhcpcd because things like the hardware address can then be changed which affects the lease.
When it's marked as up it re-negotiates it.

However, on Linux and I think Solaris, IFF_RUNNING has been repurposed
to mean "link is up or there is no way to know link status".

As part of the IPv6 RA work I added checks for IFF_RUNNING on the Linux netlink code dhcpcd uses so it's actually checked anyway which makes the proposed change above fine.



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