Cannot advertise WebTransport with externally known addresses (external static IP + port forwarding, dns, etc.)

[aschmahmann]

When running a go-libp2p host behind a NAT with port forwarding enabled or another environment where the user might know more about the addresses to advertise than go-libp2p has been able to discover (e.g. DNS addresses) users pass in their addresses via the AddrsFactory option

go-libp2p/options.go

Line 260 in 8c466ab

func AddrsFactory(factory config.AddrsFactory) Option {

As I understand it the AddrsFactory takes in the list of addresses that go-libp2p thinks it should be advertising and then allows the user to modify that list (e.g. override/remove elements, add new ones, etc.). The multiaddrs processed and returned by this function are ones that do not have the /p2p/<peerID> suffix.

Unfortunately, this behavior doesn't work for WebTransport since naively adding an additional /ip4/1.2.3.4/udp/1234/quic-v1/webtransport will be broken due to the lack of WebTransport certificates that are not added internally by go-libp2p. This is not something the user can reasonably deal with by passing the certificates themselves without understanding (and replicating) the internal go-libp2p mechanism for managing WebTransport certificates (having deterministic certificates generated with timestamps based on dividing time into fixed intervals) or finding some awkward workaround (e.g. having a loopback webtransport listener and then reading the certificates go-libp2p has emitted for the loopback listener and feeding it back into the AddrsFactory).

[BigLep]

@p-shahi : I know I missed go-libp2p triage. Was this discussed at all? Given it's relevant for IPFS Thing demos, I wanted to set expectations for people on whether it will get picked up soon or not.

https://filecoinproject.slack.com/archives/C03FFEVK30F/p1679935514021119

[MarcoPolo]

We didn't talk about this. Both prithvi and I were a bit sick so we concluded. early. I can tal now.