[Cerowrt-devel] Latest IPv6 Updates

Steven Barth cyrus at openwrt.org
Fri Dec 28 12:56:40 EST 2012

Hi guys,

the following updates / changes for IPv6 have been commited to OpenWrt 
in the last days. Most of these affect RFC 6204 CE-compliance, some are 
convenience changes.

Feel free to merge and test CeroWrt.

* Detect and delegate IPv6-specific MTU from upstream interfaces (e.g. 
tunnels, pppoe, etc.) and propagate them to downstream interfaces 
(supporting cases where IPv4-MTU and IPv6-MTU differ, e.g. 6in4, 6rd, 
6to4, ...)

* Add a default null-route for delegated prefixes (CE-requirement WPD-6)
This fixes routing loops in case packets with a destination within an 
unused / unassigned part of a delegated prefix are received.

* Added support for site-borders (interfaces which ULA-traffic might not 
cross) as specified in CE-requirement ULA-4

* Added support to override CE-requirement ULA-5 for NPT-setups (iirc 
not relevant if dnsmasq is used, as it does not follow ULA-5).

Documentation on http://wiki.openwrt.org/doc/uci/network6 has been updated.

Btw. Simon Kelley released 2.66-test4 which fixes some bugs related to 
stateful DHCPv6 and should make it usable finally. Also the new 
MTU-propagation mentioned above is now supported by dnsmasq as well.
I haven't tested it myself yet but you can try if you are brave.

I will try to make a table about the RFC requirements for Customer Edge 
(CE)-Routers soon which sums up which requirements are fulfilled and 
which are still not implemented both for CeroWrt / OpenWrt with 6relayd 
and with dnsmasq as RA/DHCPv6-server.



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