The Windows client now sets the TAP IP-interface MTU to the relay-selected MTU
before it starts bridging frames. The override is scoped like the existing
metric and default-route guards, so the previous MTU is restored when the
client exits.
The route crate now exposes `InterfaceMtuSnapshot` and `ScopedInterfaceMtu`
around `MIB_IPINTERFACE_ROW.NlMtu`, reusing the same `GetIpInterfaceEntry` and
`SetIpInterfaceEntry` path already used for metrics and default-route policy.
IPv4 MTU setup is required for startup, while IPv6 MTU setup is best-effort to
match the existing IPv6 route-protection behavior.
This intentionally leaves TAP MAC configuration as fail-fast. TAP-Windows6 does
not expose a matching set-MAC IOCTL in the driver header, so that should remain
a separate design decision.
Test Plan:
- cargo fmt --check
- cargo test -p lanparty-client-route
- cargo test -p lanparty-client-win
- cargo clippy -p lanparty-client-route -p lanparty-client-win --all-targets
-- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-gnu
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- git diff --check
- cargo check -p lanparty-client-win --target x86_64-pc-windows-gnu
(fails before this crate in ring: missing x86_64-w64-mingw32-gcc)
Refs: PLAN.md
The Windows route helper now supports a scoped DisableDefaultRoutes override
for an IP interface family. The guard snapshots the existing interface row,
sets the requested default-route disabled state, and restores the previous
state when dropped.
This is the route-crate half of neutralizing TAP default-route takeover from
PLAN.md. It intentionally does not wire the client yet, so the public API can
be reviewed independently from the client startup behavior.
The implementation keeps metric restoration and default-route restoration
separate even though both read the same IP interface row. That avoids one guard
accidentally reverting the other guard's setting when the Windows client holds
both at the same time.
Test Plan:
- cargo fmt --check
- cargo test -p lanparty-client-route
- cargo clippy -p lanparty-client-route --all-targets -- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-msvc
- cargo clippy -p lanparty-client-route --target x86_64-pc-windows-msvc --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md
Add a reversible IP interface metric boundary to `lanparty-client-route`. The
crate can now read an IPv4 or IPv6 interface metric snapshot and temporarily set
a manual interface metric with an RAII guard that restores the previous metric
and automatic-metric state on drop.
This prepares the TAP metric handling without wiring policy into the Windows
client yet. Default-route disabling is captured in snapshots for diagnostics and
future decisions, but this slice deliberately changes only `UseAutomaticMetric`
and `Metric`.
Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-msvc
- cargo clippy -p lanparty-client-route --target x86_64-pc-windows-msvc --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md
Refs: https://learn.microsoft.com/en-us/windows-hardware/drivers/network/initializeipinterfaceentry
Refs: https://learn.microsoft.com/en-us/windows/win32/api/netioapi/nf-netioapi-setipinterfaceentry
Add a small route-crate API that resolves a Windows network adapter GUID into
its interface LUID and index. The TAP adapter discovery already gives us the
NetCfgInstanceId GUID, and the route/metric work needs the corresponding IP
interface identity before it can safely inspect or adjust TAP metrics.
The implementation keeps GUID parsing local and dependency-free, then delegates
the actual identity lookup to Windows IP Helper calls. Non-Windows builds expose
the same API shape with a clear unsupported-platform error.
Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-msvc
- cargo clippy -p lanparty-client-route --target x86_64-pc-windows-msvc --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md
Add the first route-table mutation API to `lanparty-client-route`. Given the
pre-TAP best-route snapshot, the crate can now create a host route for the relay
IP on that same interface and return an RAII guard that deletes the route when
it is dropped.
The route row is initialized with `InitializeIpForwardEntry`, uses a /32 or
/128 destination prefix for the relay IP, preserves the pre-TAP interface
index/LUID, and uses the remembered next hop or an on-link unspecified next hop
when Windows reported no gateway. The guard tracks whether creation actually
succeeded so pure row-construction tests and failed creates do not try to delete
routes they did not install.
This remains a crate-level boundary only. The Windows client still reports the
pre-TAP route but does not yet hold a pin across TAP activation; that is the
next integration slice.
Test Plan:
- cargo fmt --check
- cargo test -p lanparty-client-route
- cargo clippy -p lanparty-client-route --all-targets -- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-msvc
- cargo clippy -p lanparty-client-route --target x86_64-pc-windows-msvc --all-targets -- -D warnings
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md
Refs: https://learn.microsoft.com/en-us/windows-hardware/drivers/network/createipforwardentry2
Refs: https://learn.microsoft.com/en-us/windows-hardware/drivers/network/initializeipforwardentry
Add `lanparty-client-route` as the Win32 boundary for route-table work. The
first API is intentionally read-only: `best_route_to` wraps `GetBestRoute2`
and returns the selected source address, next hop, route prefix, interface
index/LUID, and route metric for a relay destination IP.
This keeps the route-protection work separate from the QUIC client binary, so
we can typecheck the Windows IP Helper calls on this Linux host without pulling
in the `ring` build path that currently blocks full Windows binary checks.
Actual route pinning and metric mutation remain later slices.
Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- cargo check -p lanparty-client-route --target x86_64-pc-windows-msvc
- cargo clippy -p lanparty-client-route --target x86_64-pc-windows-msvc -- -D warnings
- git diff --check
Refs: PLAN.md
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