fix(relay-server): pass dummy port to lookup_host#424
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tokio::net::lookup_host requires a host:port input, so passing a bare hostname (e.g. pluto-relay-0-p2p.ovh.dev-nethermind.xyz) failed with "invalid socket address" and the relay never resolved the external host for its ENR. Use a dummy port of 0 and iterate through the resolved addresses to find the first IPv4, rather than silently giving up if the first record happens to be IPv6.
The previous assertion required the ENR's ip to be loopback after setting external_host = "www.google.com", which only held because lookup_host silently failed on a bare hostname. With the resolver fixed, the ip override now applies, so poll the ENR until a non-loopback ip is observed (matching the Go assert.Eventually test).
emlautarom1
approved these changes
May 19, 2026
| // Resolution happens asynchronously on a tick, so poll until the | ||
| // ENR reflects a non-loopback IP (mirrors the Go test using | ||
| // `assert.Eventually`). | ||
| let deadline = time::Instant::now() + time::Duration::from_secs(10); |
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nit: Could use tokio::time::timeout to make it clearer (test should take at most 10 seconds)
iamquang95
reviewed
May 19, 2026
| if let Some(ipv4) = ipv4 { | ||
| debug!("Resolved external host {external_host} to {ipv4}"); | ||
| state.set_external_host_ip(Some(ipv4)).await; | ||
| } else { |
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Should we invalidate the cache here state.set_external_host_ip(None).await;? The DNS may no longer return IPv4 for the host, so a later query could fail
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Summary
tokio::net::lookup_hostrequires ahost:portinput, so passing a bare hostname (e.g.pluto-relay-0-p2p.ovh.dev-nethermind.xyz) failed withinvalid socket addressand the relay never resolved the configuredexternal_hostfor its ENR.0so the bare hostname resolves, and iterate the resolved addresses to find the first IPv4 instead of silently giving up if the first record happens to be IPv6.Test plan
external_hostset to a hostname and verify the warningFailed to resolve external host ... invalid socket addressno longer appears/enrresponse contains the resolved IPv4 in the ENRipfieldcargo clippy --workspace --all-targets --all-features -- -D warnings