Gate uniform message padding behind --dev-uniform-padding#8997
Open
sangbida wants to merge 4 commits intoElementsProject:masterfrom
Open
Gate uniform message padding behind --dev-uniform-padding#8997sangbida wants to merge 4 commits intoElementsProject:masterfrom
sangbida wants to merge 4 commits intoElementsProject:masterfrom
Conversation
This boolean allows lightningd and connectd to be on the same page on whether the uniform padding experimental flag is enabled.
Uniform padding (sending all messages as 1460-byte chunks) breaks peers running LND-based nodes: LND disconnects on receiving a ping(num_pong_bytes=65535) with "pong bytes exceeded" instead of ignoring it as required by BOLT ElementsProject#1. Gate the feature behind --dev-uniform-padding so it is opt-in rather than forced on all connections. Nodes that only peer with CLN can enable it for the traffic analysis defence. Changelog-Changed: uniform message padding is now opt-in via the --dev-uniform-padding flag.
Lagrang3
reviewed
Mar 27, 2026
| &daemon->dev_fast_reconnect, | ||
| &dev_limit_connections_inflight, | ||
| &daemon->dev_keep_nagle)) { | ||
| &dev_limit_connections_inflight, |
Collaborator
There was a problem hiding this comment.
Format should be kept for these lines just as the lines above.
3 tasks
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
CLN 26.04rc1 introduced uniform message padding, which pads outgoing pings to prevent traffic analysis. Per BOLT #1, a num_pong_bytes >= 65532 means the recipient must not reply with a pong — it is a valid no-reply ping. However, LND does not comply with this part of the spec (they have very recently fixed this though) so to maintain interoperability between lightning implementations this feature is being gated behind an experimental flag for now.
Checklist
Before submitting the PR, ensure the following tasks are completed. If an item is not applicable to your PR, please mark it as checked:
tools/lightning-downgrade