Files

T

The gateway now has a small Linux PacketSocket wrapper for raw Ethernet frame
I/O. It resolves the configured interface with if_nametoindex, opens an
AF_PACKET/SOCK_RAW socket for ETH_P_ALL, binds it to the interface, and exposes
thin send_frame and recv_frame helpers around the owned file descriptor.

The gateway binary opens this socket after completing the relay control
handshake. The frame bridge loop is still intentionally left for a later slice,
but the process now proves the two required resources are available: relay
admission and raw L2 access on the LAN interface.

Tests cover interface-name validation and missing-interface lookup without
requiring root or CAP_NET_RAW.

Test Plan:
- cargo fmt --check
- cargo test --workspace
- cargo clippy --workspace --all-targets -- -D warnings

Refs: PLAN.md Linux AF_PACKET gateway socket

2026-05-21 18:09:03 +02:00

2.8 KiB

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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-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-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

--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; production certificate and client trust handling remain future work.

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 currently connects to the relay as role = gateway, completes the control-stream hello/welcome handshake, opens an AF_PACKET socket on the LAN interface, and then waits for shutdown. The frame bridge loop is not wired yet.

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