c-lightning: A specification compliant Lightning Network implementation in C -> ported to work with CHIPS

c-lightning is a standard compliant implementation of the Lightning Network protocol. The Lightning Network is a scalability solution for Bitcoin, enabling secure and instant transfer of funds between any two parties for any amount.

For more information about the Lightning Network please refer to http://lightning.network.

Project Status

This implementation is still very much a work in progress. It can be used for testing, but it should not be used for real funds. We do our best to identify and fix problems, and implement missing features.

Any help testing the implementation, reporting bugs, or helping with outstanding issues is very welcome. Don't hesitate to reach out to us on IRC at #lightning-dev @ freenode.net, #c-lightning @ freenode.net, or on the implementation-specific mailing list [email protected], or on the Lightning Network-wide mailing list [email protected].

Getting Started

c-lightning currently only works on Linux (and possibly Mac OS with some tweaking), and requires a locally running chipsd that is fully caught up with the network you're testing on.

Installation

Please refer to the installation documentation for detailed instructions. For the impatient here's the gist of it for Ubuntu and Debian:

sudo apt-get install -y autoconf git build-essential libtool libgmp-dev libsqlite3-dev python python3
git clone https://github.com/chips-blockchain/lightning
cd lightning
make

Starting lightningd

In order to start lightningd you will need to have a local chipsd node running:

chipsd -daemon

Once chipsd has synchronized with the network, you can start lightningd with the following command:

lightningd/lightningd --network=testnet --log-level=debug

Listing all commands:

cli/lightning-cli help will print a table of the API and lists the following commands

Opening a channel on the Bitcoin testnet

First you need to transfer some funds to lightningd so that it can open a channel:

# Returns an address <address>
cli/lightning-cli newaddr

Returns a transaction id

chips-cli sendtoaddress

Retrieves the raw transaction

chips-cli getrawtransaction

If you don't have any testcoins you can get a few from a faucet such as TPs' testnet faucet or Kiwi's testnet faucet. You can send it directly to the lightningd address.

Confirm lightningd got funds by:

# Returns an array of on-chain funds.
cli/lightning-cli listfunds

Once lightningd has funds, we can connect to a node and open a channel. Let's assume the remote node is accepting connections at <ip> (and optional <port>, if not 9735) and has the node ID <node_id>:

cli/lightning-cli connect <node_id> <ip> [<port>]
cli/lightning-cli fundchannel <node_id> <amount_in_satoshis>

This opens a connection and, on top of that connection, then opens a channel. The funding transaction needs 1 confirmations in order for the channel to be usable, and 6 to be broadcast for others to use. You can check the status of the channel using cli/lightning-cli listpeers, which after 3 confirmations (1 on testnet) should say that state is CHANNELD_NORMAL; after 6 confirmations you can use cli/lightning-cli listchannels to verify that the public field is now true.

Different states

• GOSSIPING means that you are connected to a peer but there is no payment channel yet.
• OPENINGD means that lightning_openingd is negotiating channel opening.
• CHANNELD_AWAITING_LOCKIN means that lightning_channeld is waiting until the minimum number of confirmation on the channel funding transaction.
• CHANNELD_NORMAL means your channel is operating normally.
• CHANNELD_SHUTTING_DOWN means one or both sides have asked to shut down the channel, and we're waiting for existing HTLCs to clear.
• CLOSINGD_SIGEXCHANGE means we're trying to negotiate the fee for the mutual close transaction.
• CLOSINGD_COMPLETE means we've broadcast our mutual close transaction (which spends the funding transaction) , but haven't seen it in a block yet.
• FUNDING_SPEND_SEEN means we've seen the funding transaction spent.
• ONCHAIN means that the lightning_onchaind is tracking the onchain closing of the channel.

All these states have more information about what's going on in the status field in listpeers.

Sending and receiving payments

Payments in Lightning are invoice based. The recipient creates an invoice with the expected <amount> in millisatoshi (or "any" for a donation), a unique <label> and a <description> the payer will see:

cli/lightning-cli invoice <amount> <label> <description>

This returns some internal details, and a standard invoice string called bolt11 (named after the BOLT #11 lightning spec).

The sender can feed this bolt11 string to the decodepay command to see what it is, and pay it simply using the pay command:

cli/lightning-cli pay <bolt11>

Note that there are lower-level interfaces (and more options to these interfaces) for more sophisticated use.

Configuration File

lightningd can be configured either by passing options via the command line, or via a configuration file. Command line options will always override the values in the configuration file.

To use a configuration file, create a file named "config" within your ".lightning" directory. Usually this will be ~/.lightning/config

The sender needs to compute a route to the recipient, and use that route to actually send the payment:

Configuration options are set using a key=value pair on each line of the file, for example:

alias=SLEEPYDRAGON
rgb=008000
port=9735
network=testnet

For a full list of possible lightningd configuration options, run:

lightningd/lightningd --help

Further information

JSON-RPC interface is documented in the following manual pages:

• invoice
• listinvoices
• waitinvoice
• waitanyinvoice
• delinvoice
• getroute
• sendpay
• pay
• listpayments
• decodepay

For simple access to the JSON-RPC interface you can use the cli/lightning-cli tool, or the python API client.