Extends the network plumbing to support per-interface IPv6 address
configuration.
The `Interface` protocol supports `ipv6Address` and `ipv6Gateway`.
The agent's networking RPCs carry per-family fields via new
`InterfaceAddress`, `LinkRoute`, and `DefaultRoute` types in
`ContainerizationExtras`.
`NetlinkSession` adds IPv6 methods for address and route operations.
---------
Co-authored-by: michael_crosby <michael_crosby@apple.com>
Co-authored-by: Michael Crosby <crosbymichael@gmail.com>
- Simplifies processing and validation of MAC addresses for
apple/container#1005, where we need to create MAC addresses and
corresponding link local IPv6 addresses.
- Adds Codable for IPAddress and CIDR for apple/container#1006, so we
can parse and relay IP addresses regardless of address family for port
forwards.
Here we implement the mechanism for ensuring that `container` doesn't
set up two default routes on containers that connect to multiple
networks. We'll implement the policy in apple/container#243.
