swarm: fix recursive resolving of DNS multiaddrs

[marten-seemann]

No description provided.

[marten-seemann]

The code works, but I should add a test case before we merge this.

[sukunrt]

This change looks fine to me. But should https://github.com/libp2p/go-libp2p/blob/master/p2p/transport/websocket/websocket.go#L139 ignore dnsaddr addresses since the actual host will be obtained after resolving the dnsaddr

[dennis-tra]

Just smoked-tested it with boomo and can also confirm that it works:

boomo_up{otel_scope_name="github.com/plprobelab/boomo",otel_scope_version="",peer="QmNnooDu7bfjPFoTZYxMNLWUQJyrVwtbZg5gBMjTezGAJN",transport="ws"} 1
boomo_up{otel_scope_name="github.com/plprobelab/boomo",otel_scope_version="",peer="QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa",transport="ws"} 0
boomo_up{otel_scope_name="github.com/plprobelab/boomo",otel_scope_version="",peer="QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ",transport="ws"} 0
boomo_up{otel_scope_name="github.com/plprobelab/boomo",otel_scope_version="",peer="QmbLHAnMoJPWSCR5Zhtx6BHJX9KiKNN6tpvbUcqanj75Nb",transport="ws"} 1
boomo_up{otel_scope_name="github.com/plprobelab/boomo",otel_scope_version="",peer="QmcZf59bWwK5XFi76CZX8cbJ4BhTzzA3gU1ZjYZcYW3dwt",transport="ws"} 1

(see the 1 at the end of the prometheus metric - at least for 3/5 bootstrappers). I guess QmQCU2EcMqAqQPR2i9bChDtGNJchTbq5TbXJJ16u19uLTa isn't working because rust doesn't support ws? QmaCpDMGvV2BGHeYERUEnRQAwe3N8SzbUtfsmvsqQLuvuJ is only configured with tcp.

[marten-seemann]

I added a test case, and linked the original issue.