Investigate if skipProbe is needed for other virtual channel scenarios

[vindard]

Description

We recently implemented a skip probe pathway (#1505) for instances like payments to Muun where the probe would always fail since the last hop doesn't exist, but mission control also fails any actual payments sent soon after this.

This issue is to investigate other instances where this could potentially happen. Mostly it's for services that:

• create channels on the fly (e.g. Breez, Phoenix) for:

  • brand new users
  • users that don't have enough existing receive capacity

• use other schemes like hosted channels (e.g. SBW)

Related issues:

• https://github.com/GaloyMoney/galoy/issues/32
• https://github.com/lightningnetwork/lnd/issues/3953

[nicolasburtey]

related to https://github.com/GaloyMoney/galoy/issues/32

[openoms]

Just testing hosted channels for CLN with poncho (https://github.com/rootzoll/raspiblitz/issues/3269). I expect this solution getting more popular.

The probe failes when trying to pay an invoice (with a route hint) to a hosted channel, but can be paid directly with LND.

Options:

• skip probing if the last hop is advertising hosted channels (with the feature bit) - complicated to implement.
• skip probing for all invoices containing route hints - quick, but has false positives.

[nicolasburtey]

@openoms adding the node in question to the list of skip probe peers doesn't work?

[openoms]

@openoms adding the node in question to the list of skip probe peers doesn't work?

It wouldn't be an effective solution since now any CLN and already any Eclair node can support hosted channels, they just need to start a plugin. Find some long running examples on the end of this article https://sbw.app/posts/scaling-ln-with-hosted-channels/ and for the sake of experimentation I just created two more in a few minutes.

Hosted channels are also a great way the use the liquidity of an own node remotely on mobile - so could as popular even just for private usage as using Zeus.

Also outside contributors are already planning to implement it for LND.

[openoms]

Update: poncho v0.2.0 is out and managed to pay successfully to a hosted channel with BBW. The fee was grossly overestimated, but the difference was returned.

So don't need to skip nodes offering hosted channels!

[nicolasburtey]

Probably the solution:

https://github.com/lightningnetwork/lnd/issues/6910