Support IPv6StaticDefaultGateways on OpenBMC

[Sunitha Harish]

Hi Team,

This is about supporting IPv6StaticDefaultGateways parameter on OpenBMC.

Currently we can configure the Static IPv6 network via bmcweb, and that 
gets the network interface setup and user can connect to the BMC via 
this IPv6 network.

There is no support for setting up the Static Default IPv6 gateway via 
redfish. Its been implemented as a read-only property at bmcweb, and we 
can only retrieve a single dynamically assigned IPv6 gateway address via 
redfish's "IPv6DefaultGateway" property.

There is support to set single IPv6 default gateway at phosphor-networkd 
and dbus applications via dbus calls though. But as per the IPv6 
requirements & DMTF schema standards, the IPv6StaticDefaultGateways is 
an array of IPv6Address + prefixLength parameters. So i believe, this 
has to be implemented as a "creatable" object via bmcweb + networkd + dbus.

Please share your views as how to support multiple default IPv6 gateways 
set & get at BMC via redfish.

Thanks & regards,
Sunitha