protocols/identify: Validate addresses before caching

[mxinden]

With #2232 libp2p-identify caches discovered listen addresses to provide additional addresses when dialing a peer via NetworkBehaviour::addresses_of_peer.

Before caching received listen addresses, libp2p-identify should validate these addresses. Validations:

• If the address contains a /p2p/QmXXX make sure QmXX matches the peer's PeerId.
• ...

//CC @AgeManning: This might be the reason for the dial failures you are seeing.

[thomaseizinger]

Do we want to treat validation errors as bad behaviour and disconnect from that peer?

[mxinden]

For now I would suggest we just ignore those addresses with a peer ID mismatch in libp2p-identify.

Reasoning: Maybe there is a benign way (in old versions) how this could happen. Disconnecting on mismatch might lead to large disconnects in live networks. Without measuring this beforehand, I would deem this change too risky.

Do you have some time to file a patch? I am sorry, I am a bit low on time / energy (sick). If not, I can just set the default value of cache_size to 0 for v0.40.0 and re-enable it by default with the patch in v0.41.0.

[thomaseizinger]

Do you have some time to file a patch?

Not at the moment but I am okay with disabling the current behaviour if it causes problems.

[MarcoPolo]

@thomaseizinger I'll pick this up unless you're working on it, thanks!

[thomaseizinger]

@thomaseizinger I'll pick this up unless you're working on it, thanks!

Go for it! I haven't started on this yet :)