Lightning Specification Meeting 2022/12/05

[t-bast]

The meeting will take place on Monday 2022/12/05 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

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

• Tlv stream in onion failures TLV failure message and length relaxation #1021
• Add dust exposure threshold Add a max_dust_htlc_exposure_msat #919
• Route blinding Route Blinding (Feature 24/25) #765
• Fat errors Attributable errors (feature 36/37) #1044
• Anchor outputs zero fee htlc txs test vectors Add test vectors for option_anchors_zero_fee_htlc_tx #1018
• Dual funding interactive-tx: Add dual-funding flow, using the interactive tx protocol (feature 28/29) #851
• Issue with the cltv_expiry_delta section? Error in cltv_expiry_delta setting? #1045

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.

• Onion messages BOLT 7: Onion message support (features 38/39) #759
• Offers Offers #798
• Taproot extension-bolt: simple taproot channels (feature 80/81) #995
• Closing fee range turn-based protocol option_closing_rejected: turn-based fee_range coop close (feature 60/61) #1016
• Update static channel parameters zzz-extension-bolt: dynamic commitments #1026
• Sign commitments at various feerates Add option to sign commitments at various feerates (FEAT 32/33) #1036
• Liquidity ads option_will_fund: liquidity ads #878

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.

• Fix channel pruning behavior -> fixed in eclair, lnd was already fixed, what about ldk and cln?
• Don't force close until error is received after channel_reestablish Nodes shouldn't publish their commitment when receiving outdated channel_reestablish #934
• Graph dump on gossip_timestamp_filter Inconsistent behavior around graph dump on gossip_timestamp_filter. #980
• Websocket transport websocket address type: allow transport over RFC6455 #891

Long Term Updates

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

• Channel jamming draft: Staking Credentials token issuance/redemption #1043
• Pinning attacks as related to splicing / dynamic commitments: https://lists.linuxfoundation.org/pipermail/lightning-dev/2022-August/003665.html
• Quiescence BOLT 2: quiescence protocol (feature 34/35) option_quiesce #869
• Splicing Splice draft (feature 62/63) #863
• Simplified commitment Feature 106/107: option_simplified_update. #867
• Hold htlcs before forwarding Add the ability to hold HTLCs before forwarding (FEAT 52/53) #989
• Trampoline routing Trampoline Routing (2021 edition) (Feature 56/57) #829 and Trampoline onion format (Feature 56/57) #836
• Peer storage backup Peer backup storage (feature 40/41/42/43) #881
• Anonymous gossip
• lnprototest (https://github.com/rustyrussell/lnprototest)

[t-bast]

I won't be able to attend this spec meeting, I'll let you guys get all of those PRs merged 😉
Can someone record the meeting so that we try using a tool to generate the transcript?

[Roasbeef]

larger onion errors:

• lnd has PR and also compat w/ test vectors, eclair verified with test vectors -- MERGED

dust recommendations:

• ack for t-bast, the others need to take a look at

blinded paths:

• CL has experimental option in the current release, now ready to do interop testing
• lnd has a new PR up targeting the basic interaction at the edges, looking to have something landing the next major release
• lingering error details:
  • ended up suppressing all the errors
  • in the past would turn all errors into "something happened in the errors", then ended up backing off a bit on the error suppression
  • if you're the entry point though, then might as well give them more error information
  • final error model: if you're the entry point, send a real error -- otherwise, you just say "something happened in the tunnel"

fat errors:

• related to prepay, how aggressive are we gonna be on the prepay stuff?
  • most prepay schemes let you tell how far it got, since you know how far it go
  • in this case, are fat errors needed? nice part is that then you're able to get timing information, which can help inform forwarding, etc
• option question: how do ppl feel about prepays?
  • if there's some constant re N (amount of prepay), then does that give others information about the path length, etc?
    * advertisement: implementation path?
  • new node ann?
  • just add on 2% of the fee to everything, uniform value as well
    * w/o timing is it worthwhile?
    * this seems more or less complete as well, compared to going to the drawing board to really hash out the prepay schemes
  • doesn't hold up other stuff, is now concrete
    * compared to prepay, this gives more granular information w.r.t who exactly failed the error
• concrete steps:
  • assign feature bit
  • additional TLV type to tell them to do the proper transformation
• idea re deployment:
  • coordinate re a network wide update cycle
  • add bit now, no one uses it until later date in the future (date, or node count, etc, etc)

anchor test vectors:

• on todo list for CLN+LND

dual fundign:

• re-working some txabort stuff (when to abort on that)
• current CLN release isn't interop ready, needs to fix an abort portion of it

error in ctlv delta expiry:

• ppl need to check out still

onion messaging:

• interop land, lnd has some basic interop w/ ldk

offers:

• interop land, WIP

option closing rejected:

• lnd has basic impl of, looking to release along side default fee_range, and also a position where the responder always accepts the co-op close instance
• should also send what the initiator thinks should be the reasonable fee range
• could be an odd message if we wanted to avoid the feature bit (then would also send a warning)

taproot:

• JIT nonces ftw, lnd now working to implement the new version
• shooting for EOY interop w/ LDK

[Roasbeef]

@t-bast I have a recording of the transcript, I'm gonna try this new fancy AI transcription software to see how it does (will post results here): https://github.com/openai/whisper

[t-bast]

Nice, thanks @Roasbeef !

[Roasbeef]

Here's the transcript: https://gist.github.com/Roasbeef/24533cd0cfc5310e530af96afd1e2b2b

I used the "medium" model on my laptop (takes up about 6GB while running, so will run on my work station next time instead), and it's pretty good though there're some weird words in there.

This is the command I used to generate the transcript:

whisper Lightning-Spec-Meeting_2022-12-05T20_00_19.967Z.webm --model medium

The default download from the jitsi was a webm.

[t-bast]

There are some parts that lost me ("I mean, so Vinyl Flask 2023 is what it sounds like.") but it's really nice to have a transcript, I was able to go through everything that was discussed, so that looks like a good option, thanks @Roasbeef !

[Roasbeef]

Heh I think, that was "blinded paths 2023"

…

On Tue, Dec 6, 2022, 11:50 PM Bastien Teinturier ***@***.***> wrote: There are some parts that lost me ("I mean, so Vinyl Flask 2023 is what it sounds like.") but it's really nice to have a transcript, I was able to go through everything that was discussed, so that looks like a good option, thanks @Roasbeef <https://github.com/Roasbeef> ! — Reply to this email directly, view it on GitHub <#1046 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAHTWLXSHL7UYEUJ7KMPCOTWMA6VNANCNFSM6AAAAAAST6INEA> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[ariard]

Thanks for the transcripts! Really valuable to have them.