ddidderr 89989c195a feat(client): bridge TAP frames in Windows client
Wire the Windows client run loop to move Ethernet frames between the relay
session and the opened TAP-Windows6 adapter. TAP reads use a named OS thread
because the current adapter API performs blocking synchronous reads; relay to
TAP writes use short `spawn_blocking` jobs so the async receive loop does not
block the Tokio worker.

The main function now always closes the relay session after the client run loop
finishes, including TAP pump errors. Ctrl-C still stops the client. The TAP
reader thread is intentionally detached in this first pump slice because a
blocking TAP read cannot yet be cancelled cleanly from the async side; process
exit tears it down after shutdown.

This still leaves route pinning and automatic TAP MAC/MTU configuration for
later. The README now reflects that frame pumping is wired while those Windows
network-configuration pieces remain outstanding.

Verification note: I attempted to check `lanparty-client-win` for
`x86_64-pc-windows-msvc`, but this Linux host still lacks the Windows C
headers needed by `ring`; the build stops at `assert.h` before the binary crate
can be typechecked for Windows.

Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings
- CC_x86_64_pc_windows_msvc=clang-cl AR_x86_64_pc_windows_msvc=llvm-lib \
  CARGO_TARGET_X86_64_PC_WINDOWS_MSVC_LINKER=lld-link cargo clippy \
  -p lanparty-client-tap --target x86_64-pc-windows-msvc -- -D warnings
- git diff --check

Refs: PLAN.md
2026-05-21 19:02:59 +02:00
2026-05-21 16:54:26 +02:00
2026-05-21 17:00:58 +02:00

softlan-vpn

Monorepo for a Layer 2 over QUIC LAN party bridge.

Workspace crates

  • lanparty-proto: shared frame format, MAC validation, MTU helpers.
  • lanparty-ctrl: control-plane messages (join/hello/role/version).
  • lanparty-obs: shared diagnostics/logging event models.
  • lanparty-client-core: platform-agnostic client session state.
  • lanparty-client-tap: TAP-Windows6 adapter discovery and frame I/O.
  • lanparty-client-win: Windows TAP + route/metric handling binary.
  • lanparty-gateway: Linux AF_PACKET gateway binary.
  • lanparty-relay: public QUIC relay binary.

lanparty-proto

Transport-agnostic tunnel contract shared by all binaries:

  • overlay datagram header encoding and decoding
  • Ethernet frame header parsing
  • MAC address parsing and identity validation
  • QUIC datagram to TAP MTU budget helpers

lanparty-ctrl

Reliable control-plane schema shared by the QUIC stream handlers:

  • endpoint hello messages with role, room, MAC, and datagram budget
  • server welcome, reject, peer lifecycle, stats, and disconnect messages
  • room-code, role/MAC, peer-id, and effective-MTU validation
  • length-prefixed JSON control frames for reliable QUIC streams

lanparty-obs

Shared diagnostics and structured logging vocabulary:

  • gateway/relay frame logs with MACs, ethertype, length, peer, and action
  • tunnel counters shared by control messages and runtime diagnostics
  • client connectivity/TAP diagnostics and user-facing status messages

lanparty-client-core

Platform-neutral remote client relay session:

  • relay QUIC connection with pinned relay certificate trust
  • client hello with room, virtual MAC, and datagram budget
  • welcome/reject handling with assigned peer id and effective TAP MTU
  • Ethernet frame send/receive helpers over QUIC DATAGRAM

lanparty-client-tap

Windows TAP adapter boundary:

  • TAP-Windows6 adapter discovery from the Windows network adapter registry
  • \\.\Global\{NetCfgInstanceId}.tap device path construction
  • blocking Ethernet frame reads/writes through the TAP device handle
  • TAP driver IOCTL helpers for media status, adapter MAC, and MTU

lanparty-relay

Public relay binary and relay-owned room state:

  • QUIC endpoint binding and first-stream hello/welcome admission
  • room admission for clients and gateways
  • one gateway per room, duplicate client MAC rejection, and room limits
  • stable effective room MTU chosen before Ethernet datagrams flow
  • live Ethernet datagram forwarding with no ingress reflection
  • L2 safety filters for jumbo, switch-control, DHCP-server, and IPv6-RA frames
  • peer leave cleanup for room membership and MAC indexes

Build

cargo check --workspace

Relay

cargo run -p lanparty-relay -- --listen 443/udp --dev-cert-der-out relay-cert.der

--listen accepts either a socket address or a UDP port shorthand such as 443/udp. The relay binds a QUIC endpoint, accepts a control-stream hello, replies with welcome or reject, and forwards live Ethernet QUIC datagrams between accepted peers in the same room. It currently uses a generated self-signed development certificate; --dev-cert-der-out writes that certificate so the gateway and client can pin it in development. Production certificate handling remains future work. Ethernet forwarding decisions are logged with room, peer, MAC, ethertype, action, drop reason, and target count.

Gateway

cargo run -p lanparty-gateway -- \
  --relay 203.0.113.10:443 \
  --server-name lanparty-relay.local \
  --relay-ca-cert relay-cert.der \
  --room ROOM1 \
  --interface eth0

The gateway connects to the relay as role = gateway, completes the control-stream hello/welcome handshake, opens an AF_PACKET socket on the LAN interface, and bridges Ethernet frames between the relay and wired LAN until shutdown. It tracks remote-client source MACs seen from relay traffic and periodically emits small CAM refresh frames so the physical switch keeps those MACs associated with the gateway port.

Windows Client

cargo run -p lanparty-client-win -- \
  --relay 203.0.113.10:443 \
  --server-name lanparty-relay.local \
  --relay-ca-cert relay-cert.der \
  --room ROOM1

The Windows client binary currently connects to the relay as role = client with a generated locally administered virtual MAC persisted in lanparty-client-identity.json, completes the control-stream hello/welcome handshake, and then bridges Ethernet frames between the relay and the first TAP-Windows6 adapter until shutdown. --virtual-mac can still override the stored identity for manual testing. On Windows it marks the TAP media connected and reports the driver MAC/MTU before forwarding frames. Route pinning and automatic TAP MAC/MTU configuration are not wired yet.

S
Description
A simple one-click Layer 2 tunnel software (Windows 11 client) to bridge people who cannot participate in person at a LAN party to the LAN party. And a simple server endpoint (Linux) software that runs physically at the LAN party and bridges the tunneled traffic and the real LAN network.
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