discovery+lnwire: add support for DNS host names in NodeAnnouncement msg

[Roasbeef]

Today it isn't possible to advertise a proper hostname in the NodeAnnouncement message. Historically, we've gotten around this by adding a CLI option that allows users to specify a hostname that should periodically be queried to resolve a new IP to advertise. There exist a spec proposal to add a new address type to the NodeAnnouncement message. With this implemented, we can actually remove our existing hack around this prior lack of protocol feature.

Related to this spec addition is another proposal to add a websockets type. Turns out that most web browsers (read: Chrome) doesn't allow raw websockets (so no TLS layer), which means in practice, one is required to connect via a hostname in either case. As a result, implementing this also gives us a way to expose LN p2p connection over websockets, with the caveat that the node requires a hostname, or uses some existing TPC<->WS proxy.

Steps to Completion

• Add new host name address type to lnwire.NodeAnnouncement
• Add a new config flag to allow users to set this new field.
• Extend the existing peersrpc.UpdateNodeAnnoncement struct to allow dynamic config of this new field

[gabbyprecious]

Hi @Roasbeef can I be assigned to this?

[DeGrandis]

Hi @Roasbeef , I would like to give this a go too. I'm new to this repo and would like to help. Maybe pairing with @gabbyprecious ?

Edit: after poking around, this looks to be over my head, for now. I will look for something else.

[guggero]

We don't normally assign issues to external contributors. But if you want to "claim" something, you can always create a draft (!) pull request and link the issue in the description. That way anyone looking at the issue sees that someone is working on it.

[tvolk131]

There exist a spec proposal to add a new address type to the NodeAnnouncement message.

@Roasbeef can you link the spec you're talking about? All I could find was this thread, but this doesn't seem like quite what you're proposing.

[remyers]

Is this the PR to add support for the spec change: BOLT 7: add gossip address descriptor type DNS hostname #911 ?

[Roasbeef]

@tvolk131 yep see the linked PR above ^

[m-schmoock]

Hi @Roasbeef
lightning/bolts#911 finally reached interop with Rust-Lightning and is going being merged soon. I was thinking about removing the EXPERIMENTAL checks in CLN code for the next release. But there was chatter in our Discord that LND currently won't propagate node_annoucement's that contain (optional) DNS hostnames as address descriptors. About that:

• Is this correct?
• If yes, is there an issue on your GitHub for this? (I couldn't find it)
• We likely can't remove CLN EXPERIMENTAL when LND, which is the biggest part of the network, won't propagate the node_annoucement's

[Roasbeef]

But there was chatter in our Discord that LND currently won't propagate node_annoucement's that contain (optional) DNS hostnames as address descriptors. About that:

No this is fixed now, we'll propagate new addrs that we don't yet understand.