Capability that lets a sibling module ask for a peer to be reached through a third node, by PeerId. More...
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Classes | |
| struct | librats::RelayService |
Namespaces | |
| namespace | librats |
Capability that lets a sibling module ask for a peer to be reached through a third node, by PeerId.
Published by Relay via ServiceRegistry (see service_registry.h). It is the last rung of the connectivity ladder — a direct dial, then a hole punch, then this — and the module that gives up on the rung above should not have to know anything about how the rung below works. HolePunch, for instance, learns that a target is unreachable (a symmetric NAT it declined to punch, or a rendezvous that ran out of attempts) and this is the whole contract it needs to hand the id on: no relay selection, no circuits, no policy, all of which are Relay's own business.
Resolving it returns nullptr when relaying is not enabled, which is exactly what makes the fallback optional at the consumer's side:
if (auto* relay = ctx.services.get<RelayService>()) relay->connect_via_relay(id);
The provider registers during attach(), so resolve it in start() (every attach() runs before any start()) rather than in your own attach(), where the provider may not have been attached yet. The pointer is NON-owning and valid while the node is.
Definition in file relay_service.h.
