Lightning Specification Meeting 2024/12/02

[t-bast]

The meeting will take place on Monday 2024/12/02 at 7pm UTC (5:30am Adelaide time) on Libera Chat IRC #lightning-dev. It is open to the public.

A video link is available for higher bandwidth communication: https://meet.jit.si/Lightning-Spec-Meeting

Recently Updated Proposals / Seeking Review

This section contains changes that have been opened or updated recently and need feedback from the meeting participants.

• Simplified mutual close option_simple_close (features 60/61) #1205
• Liquidity ads Extensible Liquidity Ads #1153
• Peer storage backup Peer backup storage (feature 40/41/42/43) #881
• Taproot extension-bolt: simple taproot channels (feature 80/81) #995
• Taproot gossip extension-bolt: taproot gossip (features 32/33) #1059
• BIP 353 in invoice_request Include BIP 353 name info in invoice_requests #1180
• Bolt 12 contacts: blip-0042: Bolt 12 Contacts blips#42
• Splicing Channel Splicing (feature 62/63) #1160
• Dynamic Commitments Extension/dynamic commitments #1117
• Channel jamming draft: HTLC Endorsement to Mitigate Channel Jamming #1071
• Async payments Support async payments in BOLT 12 #1149
• Clarify channel_reestablish requirements Clarify channel_reestablish requirements #1049 or Rework channel_reestablish requirements #1051

Stale Proposals

This section contains pending changes that may not need feedback from the meeting participants, unless someone explicitly asks for it during the meeting. These changes are usually waiting for implementation work to happen to drive more feedback.

• Inbound fees Inbound routing fees blips#18 and Add a bLIP for backwards-compatible inbound fees blips#22

Waiting for interop

This section contains changes that have been conceptually ACKed and are waiting for at least two implementations to fully interoperate.
They most likely don't need to be covered during the meeting, unless someone asks for updates.

• Trampoline routing Trampoline Routing (2021 edition) (Feature 56/57) #829 and Trampoline onion format (Feature 56/57) #836
• Zero reserve Add option_zero_reserve (FEATURE 64/65) #1140 (follow-up on bolt2: relax channel_reserve_satoshis requirements #1133 to include a feature bit)
• Attributable errors Attributable errors (feature 36/37) #1044
• Don't force close until error is received after channel_reestablish Nodes shouldn't publish their commitment when receiving outdated channel_reestablish #934

Long Term Updates

This section contains long-term changes that need review, but require a substantial implementation effort.

• Simplified commitment Feature 106/107: option_simplified_update. #867
• lnprototest (https://github.com/rustyrussell/lnprototest)

[t-bast]

I'm back in a timezone that is more friendly to the spec meeting ;)

[vincenzopalazzo]

I'm back in a timezone that is more friendly to the spec meeting ;)

Welcome back :)

[vincenzopalazzo]

Probably before the end of the meeting next week, we can discuss the following PRs

• meta: indexing the bolt12 #1200
• meta: update the link to the ML #1170

I feel that these just need a decision to close or merge them, in this way, we have less PRs stuck in the queue

[Roasbeef]

rbf close:

• t-bast and roasbeef to do final interop this week
• fabrice has updated with the taproot branch, and works w/ the extra nonces
• main change:
  • when you resend a shutdown, other party should also send a response
  • makes the taproot add on easier, can just add the nonces along

liquidity ads:

• updated the TLV values to not conflict with the older version of liquidity ads
  • lets you run the new and the old versions concurrently, now has distinct TLV types
• ready for impl and review

peer storage back ups:

• eclair has a version for cross compat
• do the others have a fully updated version?
  • lnd PR: Peer backup lightningnetwork/lnd#8490
  • CLN has a version in master w/ an experimental tag
• (CLN <-> eclair) to do interop testing
• bluematt has some outstanding comments, adi to respond+update PR

taproot gossip:

• post tokyo elle outlined a spec+impl road map: https://delvingbitcoin.org/t/updates-to-the-gossip-1-75-proposal-post-ln-summit-meeting/1202?u=roasbeef
  • 3 stages:
    1. You can validate the new stuff.
    2. You can announce old channels with the new stuff.
    3. You can announce new (taproot) channels with the new stuff.

bip 353 invoice request:

• good to land after @rustyrussell's final changes

splicing:

• interop zone w/ eclair <-> CLN
• eclair before only had support for unannounced channels
• dusty was able to test w/ un announced channels, everything worked fine -- need to test the gossip part
  • super close, just have one core change in CLN
  • related to rotating pubkeys, more depth than at the surface

dyn commits:

• lnd working on impl still

channel jamming:

• carla catching up w/ post tokyo revisions
• lnd PR to start to set endorsements

async payments:

• trampoline routing w/ blinded payments ready to go

blinded path related errors:

• how do you handle blinded paths 1 one hop?
  • you could simulate failures, and penalize the introduction node?
    • eclair: don't punish blinded path intro nodes at all
    • CLN: we'll remember insufficient capacity for that payment session
• BOLT 12 version:
  • onion messaging addition gives an ability to send more error information
    * soft errors:
  • send this back, but don't close the error
  • more specific solution than using onion messaging