[OpenWrt-Devel] DHCPv6 flash renumbering patches with HE tunnel breaks
Arjen de Korte
arjen+openwrt at de-korte.org
Wed Mar 25 16:49:57 EDT 2015
Citeren Arjen de Korte <arjen+openwrt at de-korte.org>:
> I use an IPv6 tunnel provided by Hurricane Electric to provide IPv6
> access for my LAN. HE tunnels are configured statically (no DHCPv6 /
> PD involved) and for the purpose of understanding what ranges are
> used, assume the following:
> WAN - 2001:DB8:DEAD:BEEF::/64 (local tunnel endpoint at
> LAN - 2001:DB8:CAFE:BABE::/64 (note this is not a subnet of the
> WAN, I think this may be important here)
> I use both SLAAC + DHCPv6 on the LAN. Devices with DHCPv6 capability
> are configured with IPv4+IPv6 addresses in /etc/config/network.
In /etc/config/dhcp of course.
> This has worked flawlessly in Barrier Breaker so far. After
> migrating to Chaos Calmer, DHCPv6 was essentially broken. Devices
> that previously were using addresses configured through DHCPv6 are
> now using SLAAC only.
> Looking in the logs of one of the DHCPv6 clients (a laptop using
> NetworkManager), I noticed that it was handed out a lease with a
> preferred lifetime of just one (1) second. Consequently, it would
> attempt to renew the lease it gets every second, causing
> intermittent IPv6 availability (if at all) and huge CPU spikes on
> the router at the times the client connected. Reverting back to the
> version of odhcpd from Barrier Breaker fixed both these problems and
> DHCPv6 was useable again.
> Digging into the code, the following commit broke odhcpd in my
> router (Netgear WNDR4300):
> dhcpv6: allow flash renumbering in hybrid management mode
> Neither of the following two changes to the same part of this code
> fixed things:
> dhcpv6: fix calculation of T1 and T2
> DHCPv6: enable flash-renumbering hack only for /64 prefixes
> I'm not quite sure what problem these commits are trying to solve,
> but it looks to me that the logic behind it is somehow not working
> for me. For all intents and purposes, the IPv6 addresses I use are
> static, so I see no reason why it would be necessary to renumber
> addresses at all.
> Any thoughts?
> openwrt-devel mailing list
> openwrt-devel at lists.openwrt.org
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