chore: update resolved enr ip when using dns4-domain-name flag

[alrevuelta]

Background

When using dns4-domain-name eg

./build/wakunode2 --dns4-domain-name=google.com --discv5-discovery=true

The node creates an ENR with ip 0.0.0.0 and the multi is constructed using that ip /ip4/0.0.0.0/tcp/60000/p2p/16Uiu2HAmFj9mVkzj81XBFTVK1475iKoPPiakdgZtoPTtPaTYqqRy.

Example of the generated ENR with the above command (decode it here)

enr:-Ki4QAnkkUPeFFRuIxB9KkPQqO9lKIgFxc84egqGM7mBj7bdPGlUxsnqERtpD1Z2i0-nVxyyDquUlPAq7-u9KcQxbNkBgmlkgnY0gmlwhAAAAACKbXVsdGlhZGRyc5EADzYKZ29vZ2xlLmNvbQbqYIlzZWNwMjU2azGhAy2kCEHyIKJ1iAyAzger0hd5kzbxgpYJyOvLFfzElg9Yg3RjcILqYIV3YWt1MgE

The thing is that since discv5 doesn't understand our multiaddrs field, this node won't be discoverable by disv5, since the address that is being advertised is 0.0.0.0.

In other protocols using libp2p and discv5 (eg Ethereum) the address that is advertised in the enr is the ip that results of resolving dns4-domain-name.

Example. In prysm using the following, will lead to an ENR that contains the IP that resolved from google.com. See logs:

docker run prysmaticlabs/prysm-beacon-chain:latest --p2p-host-dns=google.com --accept-terms-of-use

Acceptance criteria

• When running ./build/wakunode2 --dns4-domain-name=some_domain the constructed ENR ip field contains the resolved IP instead of just 0.0.0.0.

[gabrielmer]

Weekly Update

• next: analyze and fix issue

[gabrielmer]

Weekly Update

• achieved: implemented solution that does DNS IP resolution during node bringup when no external IP is found but a DNS address is provided.
  Validated and tested "happy paths" of the solution, raised draft PR and got feedback about the solution
• next: discuss and define the system's behavior on errors, implement error handling and adding tests for this feature.

[gabrielmer]

Weekly Update

• achieved: added error handling and tests, received new feedback and addressed the comments
• next: get the new version reviewed and merge if approved

[gabrielmer]

Weekly Update

• achieved: addressed feedback and merged