Remote clients need a stable locally administered MAC address so the relay,
gateway, DHCP lease, and LAN peers keep seeing the same tunnel identity across
runs. Requiring users to pass `--virtual-mac` made that responsibility manual.
Add a platform-neutral client identity store that loads a JSON identity file or
generates a new valid virtual MAC with OS randomness and persists it. The file
stores the MAC in the same string form shown by the CLI. The Windows client now
uses `lanparty-client-identity.json` by default while keeping `--virtual-mac` as
a manual test override.
TAP binding still remains future work; this slice only owns the client identity
that will be assigned to the TAP adapter.
Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- git diff --check
Refs: PLAN.md MAC identity
lanparty-client-core now owns the platform-neutral remote client relay session.
It validates relay trust input, room, virtual MAC identity, and datagram budget,
then connects to the relay, sends a client hello, and stores the assigned
welcome metadata.
The session exposes Ethernet datagram send and receive helpers that stamp
outgoing frames with the relay-assigned room and peer ids, ignore frames for
other rooms or from itself, and reject malformed Ethernet payloads before
handing them to the future TAP bridge.
The loopback Quinn test verifies the full client-side control and datagram path
without requiring Windows TAP access: pinned certificate trust, role = client
hello, announced virtual MAC, welcome parsing, and Ethernet datagrams in both
directions.
Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
Refs: PLAN.md Windows client relay connection and QUIC datagrams
ddidderr
