Add end-to-end tests for egress to a 4via6 target (an address behind a
subnet router advertising a 4via6 route). Tests include:
- TestConnector4via6Egress/HAEgress: egress to an in-cluster Connector
subnet router. Test requires a dual stack cluster.
- TestHostSubnetRouter4via6Egress/HAEgress: egress to a subnet router that
runs on the test host as a tsnet node. Use RegisterFallbackTCPHandler to
mock the backend response without requiring forwarding on to a backend node
(for test simplicity).
Also update end-to-end test acl for 4via6 routes, and install a dedicated
ProxyClass to accept routes.
Updates tailscale/corp#45732
Signed-off-by: Becky Pauley <becky@tailscale.com>
BeckyPauley
b3766d4fea