lit

README

lit - a lightning node you can run on your own

Under development, not for use with real money.

Setup

Prerequisites

• Git

• Go

• make

• (Optional, Windows) Cygwin

• (Optional, for full test suite) Python 3 + requests library from PyPI

Downloading

Clone the repo from git

git clone https://github.com/mit-dci/lit
cd lit

or go get it

go get -v github.com/mit-dci/lit

Installation

Linux, macOS, Cygwin, etc.

You can either use Go's built-in dependency management and build tool

cd {GOPATH}/src/github.com/mit-dci/lit
go get -v ./...
go build

or use the Makefile

make # or make all

To run the python integration tests (which requires bitcoind), run make test with-python=false

Windows

Install Cygwin and follow the setup instructions or download prebuilt binaries from

1. Make sure that environmental variable %GOPATH% is initizlized correctly.

2. Download required dependencies and then build with:

go get -v ./...
cd %GOPATH%\src\github.com\mit-dci\lit
go build -v .
go build -v .\cmd\lit-af

Running lit

The below command will run Lit on the Bitcoin testnet3 network

(Note: Windows users should take off ./ but need to change lit to lit.exe)

./lit --tn3=true

The words yup, yes, y, true, 1, ok, enable, on can be used to specify that Lit automatically connect to peers fetched from a list of DNS seeds. It can also be replaced by the address of the node you wish to connect to. For example for the btc testnet3:

./lit --tn3=localhost

It will use default port for different nodes. See the "Command line arguments" section.

Packaging

You can make an archive package for any distribution by doing:

./build/releasebuild.sh <os> <arch>

and it will be placed in build/_releasedir. It should support any OS that Go and lit's dependencies support. In place of windows use win and in place of 386 use i386.

You can also package for Linux, macOS, and Windows in both amd64 and i386 architectures by running make package. (NOTE: macOS is amd64 only)

Running ./build/releasebuild.sh clean cleans the directories it generates.

Using Lightning

Once you are done setting up lit, you can read about

• the different command line arguments
• the various folders or
• checkout the Walkthrough

Contributing

Pull Requests and Issues are most welcome, checkout Contributing to get started.

Command line arguments

When starting lit, the following command line arguments are available. The following commands may also be specified in lit.conf which is automatically generated on startup with tn3=1 by default.

Connecting to networks

Arguments	Details	Default Port
--tn3 <nodeHostName>	connect to nodeHostName, which is a bitcoin testnet3 node.	18333
--reg <nodeHostName>	connect to nodeHostName, which is a bitcoin regtest node.	18444
--lt4 <nodeHostName>	connect to nodeHostName, which is a litecoin testnet4 node.	19335

Other settings

Arguments	Details
-v or --verbose	Verbose; log everything to stdout as well as the lit.log file. Lots of text.
--dir <folderPath>	Use folderPath as the directory. By default, saves to ~/.lit/.
-p or --rpcport <portNumber>	Listen for RPC clients on port portNumber. Defaults to 8001. Useful when you want to run multiple lit nodes on the same computer (also need the --dir option).
-r or --reSync	Try to re-sync to the blockchain.

Folders

Folder Name	Details
bech32	Util for the Bech32 format
btcutil	Bitcoin-specific libraries
build	Tools used for building Lit
cmd	Has some rpc client code to interact with the lit node. Not much there yet
coinparam	Information and other constants for identifying currencies
consts	Global constants
crypto	Utility cryptographic libraries
dlc	Discreet Log Contracts
docs	Writeups for setting up things and screenshots
elkrem	A hash-tree for storing log(n) items instead of n
litrpc	Websockets based RPC connection
lndc	Lightning network data connection -- send encrypted / authenticated messages between nodes
lnutil	Widely used utility functions
portxo	Portable utxo format, exchangable between node and base wallet (or between wallets). Should make this into a BIP once it's more stable.
powless	Introduces a web API chainhook in addition to the uspv one
qln	A quick channel implementation with databases. Doesn't do multihop yet.
sig64	Library to make signatures 64 bytes instead of 71 or 72 or something
snap	Snapcraft metadata
test	Python Integration tests
uspv	Deals with the network layer, sending network messages and filtering what to hand over to wallit
wallit	Deals with storing and retrieving utxos, creating and signing transactions
watchtower	Unlinkable outsourcing of channel monitoring
wire	Tools for working with binary data structures in Bitcoin

Hierarchy of packages

One instance of lit has one litNode (package qln).

LitNodes manage lndc connections to other litnodes, manage all channels, rpc listener, and the ln.db. Litnodes then initialize and contol wallits.

A litNode can have multiple wallits; each must have different params. For example, there can be a testnet3 wallit, and a regtest wallit. Eventually it might make sense to support a root key per wallit, but right now the litNode gives a rootPrivkey to each wallet on startup. Wallits each have a db file which tracks utxos, addresses, and outpoints to watch for the upper litNode. Wallits do not directly do any network communication. Instead, wallits have one or more chainhooks; a chainhook is an interface that talks to the blockchain.

One package that implements the chainhook interface is uspv. Uspv deals with headers, wire messages to fullnodes, filters, and all the other mess that is contemporary SPV.

(in theory it shouldn't be too hard to write a package that implements the chainhook interface and talks to some block explorer. Maybe if you ran your own explorer and authed and stuff that'd be OK.)

Dependency graph

License

MIT