SetNet.Relay 1.1.0

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SetNet.Relay

A TURN-style relay hub for SetNet.

Some peers simply can't connect to each other directly — symmetric NATs, restrictive firewalls, mobile carriers. SetNet.Relay gives them a fallback: both peers connect to a shared server, one allocates a relay session (getting a join code), the other joins by code, and from then on either can push opaque bytes that the server forwards to the rest of the session. The relay never inspects the payload, so you can tunnel anything through it — a custom protocol, host-authoritative game traffic, even another framed stream. Added by composition — no base class.

Install

dotnet add package SetNet
dotnet add package SetNet.Relay

Usage

Call RelayRuntime.Enable() once at startup on both ends (before handler discovery).

Server — just turn the hub on:

RelayRuntime.Enable();
server.UseRelay();

Host client — allocate a session and share the code:

RelayRuntime.Enable();
var relay = client.UseRelay();

relay.PeerJoined += id => Console.WriteLine($"peer {id} joined");
relay.PeerLeft   += id => Console.WriteLine($"peer {id} left");
relay.Received   += (from, data) => Handle(from, data);

string code = await relay.AllocateAsync(maxPeers: 4);   // give this code to the others

Guest client — join by code and exchange bytes:

var relay = client.UseRelay();
relay.Received += (from, data) => Handle(from, data);

await relay.JoinAsync(code);
await relay.SendAsync(payload);                 // → all other members
await relay.SendToAsync(hostPeerId, payload);   // → one member

API

Server: server.UseRelay() — enable the relay hub.

Client: var relay = client.UseRelay() → RelayClient

RelayRuntime.Enable() — one-time bootstrap so the relay handlers are discovered.

Notes

• Reserved wire types 65498 / 65499 / 65500. Don't reuse them.
• Opaque forwarding. The relay copies bytes between members and never deserializes them — pick DeliveryMethod.Unreliable for latency-tolerant traffic (over a UDP/Both transport) or the default Reliable. Keep unreliable payloads under the transport's datagram limit (~1200 B on UDP).
• Relay vs Rooms. Rooms broadcast typed messages through your serializer and are built for lobby/game membership. Relay forwards raw opaque bytes with a per-sender id and 1:1 addressing — the right tool for NAT fallback and tunnelling. Use Rooms for gameplay; reach for Relay when peers can't connect directly.
• Node-local sessions. Sessions live on the relay server that created them (like Rooms/Voice); run one relay endpoint, or shard clients so both peers of a session land on the same node.
• Secure it. The relay carries whatever bytes it's given to anyone with the code — gate access with SetNet.Auth and run over TLS if the tunnelled traffic is sensitive.

Documentation & source

• 🐙 https://github.com/Povstalez/SetNet — full module catalog in docs/MODULES.md

License

MIT