e5e134ddac
In this commit, we give the legacy ChanCloser a single owner, rather than letting two goroutines advance it. The peer's channelManager drives the state machine for the Shutdown and ClosingSigned messages that come off the wire, and for local close requests. The link drives it as well: while we wait for the channel to drain we register a flush hook, and the link invokes that hook from its own goroutine, where it called BeginNegotiation directly. Nothing kept the two apart, so the state field, the priorFeeOffers map, and the signing step could all be touched at once. Under `go test -race` this shows up as a data race on the state field. Rather than reach for a lock, we route the flush through the channelManager. The hook now only reports the channel ID over a new chanCloseFlushed channel, and handleChanFlushed picks it up next to the close messages. Every transition, the cached offer processing, the fee map, and the signing then happen on the one goroutine, so the closer needs no synchronization of its own. We spell that out on the type, since it's an invariant a new caller can break from the outside. The report goes out from a fresh goroutine, which matters more than it looks. The link may well be holding its own lock while it invokes the hook, and channelManager reaches for that same lock in DisableAdds, so blocking on the handoff would trade the race for a deadlock. The `go` in front of RemoveLink just above it is there for the same reason. We look the closer up with a plain map load rather than through fetchActiveChanCloser, as that one builds a fresh closer when it doesn't find an existing one, and a flush that lands after the negotiation was torn down has no business starting a new negotiation. One behavior change falls out of the move: the flush path now runs the same finalization tail as the message path. It skipped that before, so a responder that drained a cached offer would reach closeFinished and broadcast, but nothing ran finalizeChanClosure until the next close message showed up, and having already sent its final signature, there may not be one. The link == nil path already ran the tail, so this makes all three paths agree. The new test drives a close with a link that hands us the flush hook instead of running it inline, so we can check that negotiation waits on the report, and that a report for a channel we have no closer for is dropped. |
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|---|---|---|
| .claude/commands | ||
| .gemini | ||
| .github | ||
| .vscode | ||
| actor | ||
| aezeed | ||
| aliasmgr | ||
| amp | ||
| autopilot | ||
| batch | ||
| blockcache | ||
| bolt12 | ||
| brontide | ||
| buffer | ||
| build | ||
| cert | ||
| chainio | ||
| chainntnfs | ||
| chainparams | ||
| chainreg | ||
| chanacceptor | ||
| chanbackup | ||
| chanfitness | ||
| channeldb | ||
| channelnotifier | ||
| chanstate | ||
| clock | ||
| cluster | ||
| cmd | ||
| contractcourt | ||
| contrib | ||
| discovery | ||
| docker | ||
| docs | ||
| feature | ||
| fn | ||
| funding | ||
| graph | ||
| healthcheck | ||
| htlcswitch | ||
| input | ||
| internal/musig2v040 | ||
| invoices | ||
| itest | ||
| keychain | ||
| kvdb | ||
| labels | ||
| lncfg | ||
| lnencrypt | ||
| lnmock | ||
| lnpeer | ||
| lnrpc | ||
| lntest | ||
| lntypes | ||
| lnutils | ||
| lnwallet | ||
| lnwire | ||
| macaroons | ||
| make | ||
| mobile | ||
| monitoring | ||
| msgmux | ||
| multimutex | ||
| nat | ||
| netann | ||
| onionmessage | ||
| payments/db | ||
| peer | ||
| peernotifier | ||
| pool | ||
| protofsm | ||
| queue | ||
| record | ||
| routing | ||
| rpcperms | ||
| scripts | ||
| shachain | ||
| signal | ||
| sqldb | ||
| subscribe | ||
| sweep | ||
| ticker | ||
| tlv | ||
| tools | ||
| tor | ||
| walletunlocker | ||
| watchtower | ||
| zpay32 | ||
| .editorconfig | ||
| .gitignore | ||
| .golangci.yml | ||
| .protolint.yaml | ||
| accessman.go | ||
| accessman_test.go | ||
| channel_notifier.go | ||
| chanrestore.go | ||
| config.go | ||
| config_builder.go | ||
| config_onion_ratelimit_test.go | ||
| config_prod.go | ||
| config_test.go | ||
| config_test_native_sql.go | ||
| dev.Dockerfile | ||
| doc.go | ||
| Dockerfile | ||
| go.mod | ||
| go.sum | ||
| intercepted_forward.go | ||
| LICENSE | ||
| lnd.go | ||
| log.go | ||
| logo.png | ||
| Makefile | ||
| pilot.go | ||
| README.md | ||
| rpcserver.go | ||
| rpcserver_test.go | ||
| sample-lnd.conf | ||
| SECURITY.md | ||
| server.go | ||
| server_test.go | ||
| sqlc.yaml | ||
| subrpcserver_config.go | ||
| sweeper_wallet.go | ||
| tls_manager.go | ||
| tls_manager_test.go | ||
| types.go | ||
| witness_beacon.go | ||
| witness_beacon_test.go | ||
Lightning Network Daemon
The Lightning Network Daemon (lnd) - is a complete implementation of a
Lightning Network node. lnd has several pluggable back-end
chain services including btcd (a
full-node), bitcoind, and
neutrino (a new experimental light client). The project's codebase uses the
btcsuite set of Bitcoin libraries, and also
exports a large set of isolated re-usable Lightning Network related libraries
within it. In the current state lnd is capable of:
- Creating channels.
- Closing channels.
- Completely managing all channel states (including the exceptional ones!).
- Maintaining a fully authenticated+validated channel graph.
- Performing path finding within the network, passively forwarding incoming payments.
- Sending outgoing onion-encrypted payments through the network.
- Updating advertised fee schedules.
- Automatic channel management (
autopilot).
Lightning Network Specification Compliance
lnd fully conforms to the Lightning Network specification
(BOLTs). BOLT stands for:
Basis of Lightning Technology. The specifications are currently being drafted
by several groups of implementers based around the world including the
developers of lnd. The set of specification documents as well as our
implementation of the specification are still a work-in-progress. With that
said, the current status of lnd's BOLT compliance is:
- BOLT 1: Base Protocol
- BOLT 2: Peer Protocol for Channel Management
- BOLT 3: Bitcoin Transaction and Script Formats
- BOLT 4: Onion Routing Protocol
- BOLT 5: Recommendations for On-chain Transaction Handling
- BOLT 7: P2P Node and Channel Discovery
- BOLT 8: Encrypted and Authenticated Transport
- BOLT 9: Assigned Feature Flags
- BOLT 10: DNS Bootstrap and Assisted Node Location
- BOLT 11: Invoice Protocol for Lightning Payments
Developer Resources
The daemon has been designed to be as developer friendly as possible in order
to facilitate application development on top of lnd. Two primary RPC
interfaces are exported: an HTTP REST API, and a gRPC
service. The exported APIs are not yet stable, so be warned: they may change
drastically in the near future.
An automatically generated set of documentation for the RPC APIs can be found at api.lightning.community. A set of developer resources including guides, articles, example applications and community resources can be found at: docs.lightning.engineering.
Finally, we also have an active
Slack where protocol developers, application developers, testers and users gather to
discuss various aspects of lnd and also Lightning in general.
First-time contributors are highly encouraged to start with code review first, before creating their own Pull Requests.
Installation
In order to build from source, please see the installation instructions.
Docker
To run lnd from Docker, please see the main Docker instructions
IRC
- irc.libera.chat
- channel #lnd
- webchat
Safety
When operating a mainnet lnd node, please refer to our operational safety
guidelines. It is important to note that lnd is still
beta software and that ignoring these operational guidelines can lead to
loss of funds.
Security
The developers of lnd take security very seriously. The disclosure of
security vulnerabilities helps us secure the health of lnd, privacy of our
users, and also the health of the Lightning Network as a whole. If you find
any issues regarding security or privacy, please disclose the information
responsibly by sending an email to security at lightning dot engineering,
preferably encrypted using our designated PGP key
(91FE464CD75101DA6B6BAB60555C6465E5BCB3AF) which can be found
here.