a188657b2f
In this commit, we introduce a new subsystem for the gossiper: the SyncManager. This subsystem is a major overhaul on the way the daemon performs the graph query sync state machine with peers. Along with this subsystem, we also introduce the concept of an active syncer. An active syncer is simply a GossipSyncer currently operating under an ActiveSync sync type. Before this commit, all GossipSyncer's would act as active syncers, which means that we were receiving new graph updates from all of them. This isn't necessary, as it greatly increases bandwidth usage as the network grows. The SyncManager changes this by requiring a specific number of active syncers. Once we reach this specified number, any future peers will have a GossipSyncer with a PassiveSync sync type. It is responsible for three main things: 1. Choosing different peers randomly to receive graph updates from to ensure we don't only receive them from the same set of peers. 2. Choosing different peers to force a historical sync with to ensure we have as much of the public network as possible. The first syncer registered with the manager will also attempt a historical sync. 3. Managing an in-order queue of active syncers where the next cannot be started until the current one has completed its state machine to ensure they don't overlap and request the same set of channels, which significantly reduces bandwidth usage and addresses a number of issues.
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 API's 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 talks, articles, and example applications can be found at: dev.lightning.community.
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.
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.freenode.net
- channel #lnd
- webchat
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.