(r225485). When setting an interface name to it, the following
configurations will be enabled:
1. "no_radr" is set to all IPv6 interfaces automatically.
2. "-no_radr accept_rtadv" will be set only for $ipv6_cpe_wanif. This is
done just before evaluating $ifconfig_IF_ipv6 in the rc.d scripts (this
means you can manually supersede this configuration if necessary).
3. The node will add RA-sending routers to the default router list
even if net.inet6.ip6.forwarding=1.
This mode is added to conform to RFC 6204 (a router which connects
the end-user network to a service provider network). To enable
packet forwarding, you still need to set ipv6_gateway_enable=YES.
Note that accepting router entries into the default router list when
packet forwarding capability and a routing daemon are enabled can
result in messing up the routing table. To minimize such unexpected
behaviors, "no_radr" is set on all interfaces but $ipv6_cpe_wanif.
Approved by: re (bz)
049087a0f3