relay

Rings TCP/UDP relay example

Turns a Rings overlay link into a transparent byte pipe. A server node exposes a local socket under a service name; a client node binds a local listener that forwards every connection/flow to that service across the overlay. TCP and UDP share the same pure relay protocol — only the TransportKind differs.

  socket ─▶ client tunnel ─▶ overlay ─▶ server `echo` service ─▶ local echo server
         ◀───────────────────── echoed bytes ─────────────────────────┘

The core flow lives in src/lib.rs and is shared verbatim by the runnable demos and the integration tests, so they exercise the same code.

Run

cargo run -p rings-relay-example --example rings-tcp-relay-example
cargo run -p rings-relay-example --example rings-udp-relay-example

Each demo spins up two in-process nodes, links them, and prints the bytes the relay echoed back.

Test

cargo test -p rings-relay-example

Three integration tests:

• tcp_relay_round_trip / udp_relay_round_trip — A → B → local echo over the overlay;
• relay_to_google — A → B → google.com:80: the relay node B exposes a service pointing at a real external host, the client A tunnels to it over rings and does an HTTP GET, and the test asserts the bytes that came back are a genuine HTTP response from Google (A never touches Google directly). Needs outbound internet on the relay node.

All run the full round-trip when an overlay link can be established (WebRTC/ICE); in environments without UDP/STUN connectivity (or internet, for relay_to_google) they skip with a notice instead of failing spuriously.