Remove TestGrantViaExitNodeSteering and TestGrantViaMixedSteering.
Exit node traffic forwarding through via grants cannot be validated
with curl/traceroute in Docker containers because Tailscale exit nodes
strip locally-connected subnets from their forwarding filter.
The correctness of via exit steering is validated by:
- Golden MapResponse comparison (TestViaGrantMapCompat with GRANT-V31
and GRANT-V36) comparing full netmap output against Tailscale SaaS
- Filter rule compatibility (TestGrantsCompat with GRANT-V14 through
GRANT-V36) comparing per-node PacketFilter rules against Tailscale SaaS
- TestGrantViaSubnetSteering (kept) validates via subnet steering with
actual curl/traceroute through Docker, which works for subnet routes
Updates #2180
Add golden test data for via exit route steering and fix via exit grant compilation to match Tailscale SaaS behavior. Includes MapResponse golden tests for via grant route steering verification.
Updates #2180
Add three tests that verify control plane behavior for grant policies:
- TestGrantViaSubnetFilterRules: verifies the router's PacketFilter
contains destination rules for via-steered subnets. Without per-node
filter compilation for via grants, these rules were missing and the
router would drop forwarded traffic.
- TestGrantViaExitNodeFilterRules: same verification for exit nodes
with via grants steering autogroup:internet traffic.
- TestGrantIPv6OnlyPrefixACL: verifies that address-based aliases
(Prefix, Host) resolve to exactly the literal prefix and do not
expand to include the matching node's other IP addresses. An
IPv6-only host definition produces only IPv6 filter rules.
Updates #2180
Add servertest grant policy control plane tests covering basic grants, via grants, and cap grants. Fix ReduceRoutes in State to apply route reduction to non-via routes first, then append via-included routes, preventing via grant routes from being incorrectly filtered.
Updates #2180
