ipfs p2p listen and foward should show actual port when listening on 0

[hsanjuan]

Version information:

master

Type:

Enhancement

Description:

ipfs p2p forward and ipfs p2p listen commands take a listen-address or a target address. It works with /ip4/127.0.0.1/tcp/0 but ipfs p2p ls does still show 0 instead of the actual port it bound to (which should be a random available one). This can only be discovered with lsof or similar (I think).

Ideally, p2p ls should list the bind-address with the actual port.

[overbool]

https://github.com/ipfs/go-ipfs/blob/1e0d53fe3cb32be903d768495fd0526002a03c63/p2p/local.go#L109-L111

I think we should use:

func (l *localListener) ListenAddress() ma.Multiaddr {
	return l.listener.Multiaddr()
}

[Stebalien]

We could also just set laddr to that address (and/or not even store it?). However, we need to make sure we can tell which forwarders were created with dynamic ports and which weren't (see: #5460 (comment)).

[overbool]

@Stebalien Should target address in ipfs p2p listen accept 0 port? I don't think it makes sense here.

[Stebalien]

I agree. We should prevent that.

[hsanjuan]

Ah yes, for p2p listen it doesn't make sense. Only for listener local addresses.

[hsanjuan]

Also, launching two forward with a /tcp/0 shows listener already registered.