Olaoluwa Osuntokun
505421db2c
This commit fixes a prior bug which would cause the set of HTLC’s on a
node’s commitment to potentially overflow if an HTLC was accepted or
attempted to be forwarded that but the commitment transaction over the
maximum allowed HTLC’s on a commitment transaction. This would cause
the HTLC to silently be rejected or cause a connection disconnect. In
either case, this would cause the two states to be desynchronized any
pending HTLC’s to be ignored.
We fix this issue by introducing the concept of a bounded channel,
which is a channel in which the number of items send and recevied over
the channel must be balanced in order to allow a new send to succeed
w/o blocking. We achieve this by using a chan struct{} as a semaphore
and decrement it each time a packet it sent, increasing the semaphore
one a packet is received. This creates a channel that we can use to
ensure the switch never sends more than N HTLC’s to a link before any
of the HTLC’s have been settled.
With this bug fix, it’s now once again possible to trigger sustained
bursts of payments through lnd nodes.
Lightning Network Daemon
The Lightning Network Daemon (lnd) - is a complete implementation of a
Lightning Network node and currently
deployed on testnet4 - the Bitcoin Test Network. It utilizes an
upcoming upgrade to Bitcoin: Segregated Witness (segwit). The
project's codebase uses the btcsuite set
of Bitcoin libraries, and is currently dependant on btcd.
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
Lightning Network Specification Compliance
lnd doesn't yet fully conform to the Lightning Network specification
(BOLT's). BOLT stands
for: Basic of Lightning Technologies. 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, lnd the current status of lnd's BOLT compliance is:
- BOLT 1: Base Protocol
lndcurrently utilizes a distinct wire format which was created before the emgergence of the current draft of BOLT specifications. We don't have aninitmessage, but we do have analogues to all the other defined message types.
- BOLT 2: Peer Protocol for Channel Management
lndimplements all the functionality defined within the document, however we currently use a different set of wire messages. Additionally,lnduses a distinct commitment update state-machine and doesn't yet support dynamically updating commitment fees.
- BOLT 3: Bitcoin Transaction and Script Formats
lndcurrently uses a commitment design from a prior iteration of the protocol. Revocation secret generation is handled byelkremand our scripts are slightly different.
- 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
Installation
In order to build from source, the following build dependencies are required:
-
Go: Installation instructions can be found here.
It is recommended to add
$GOPATH/binto yourPATHat this point. Note: If you are building withGo 1.5, then you'll need to enable the vendor experiment by setting theGO15VENDOREXPERIMENTenvironment variable to1. If you're usingGo 1.6or later, then it is safe to skip this step. -
Glide: This project uses
Glideto manage dependencies as well as to provide reproducible builds. To installGlide, execute the following command (assumes you already have Go properly installed):$ go get -u github.com/Masterminds/glide -
btcd: This project currently requires
btcdwith segwit support, which is not yet merged into the master branch. Instead, roasbeef maintains a fork with his segwit implementation applied. To install, please see the installation instructions.
With the preliminary steps completed, to install lnd, lncli, and all
related dependencies run the following commands:
$ git clone https://github.com/lightningnetwork/lnd $GOPATH/src/github.com/lightningnetwork/lnd
$ cd $GOPATH/src/github.com/lightningnetwork/lnd
$ glide install
$ go install . ./cmd/...
Updating
To update your version of lnd to the latest version run the following
commands:
$ cd $GOPATH/src/github.com/lightningnetwork/lnd
$ git pull && glide install
$ go install . ./cmd/...
Tests
To check that lnd was installed properly run the following command:
go install; go test -v -p 1 $(go list ./... | grep -v '/vendor/')
IRC
- irc.freenode.net
- channel #lnd
- webchat