Trampoline plugin

This is a trampoline plugin for Core Lightning that allows you to facilitate trampoline payments. Currently it is not using the trampoline protocol as defined in Trampoline Routing and Trampoline onion format, but a custom protocol.

Installation

In order to install trampoline you have to compile from source.

Prerequisites

• Rust installation
• Core lightning >= v23.11.

Compilation

Run make release in the root folder of this repository. The binary will be target/release/trampoline.

Running

Run cln with --plugin=trampoline

There's configuration options for the trampoline plugin that can to be passed to core lightning on startup.

--trampoline-policy-cltv-delta <arg>              Cltv expiry delta for the trampoline routing policy. Any routes where
                                                  the total cltv delta is lower than this number will not be tried.
                                                   (default: 1008)
--trampoline-no-self-route-hints                  If this flag is set, invoices where the current node is in an invoice
                                                  route hint are not supported. This can be useful if there are other
                                                  important plugins acting only on forwards. The trampoline plugin will
                                                  'receive' and 'pay', so has different dynamics.
--trampoline-policy-fee-per-satoshi <arg>         This is the proportional fee to charge for every trampoline payment
                                                  which passes through. As percentages are too coarse, it's in
                                                  millionths, so 10000 is 1%, 1000 is 0.1%. (default: 5000)
--trampoline-policy-fee-base <arg>                The base fee to charge for every trampoline payment which passes
                                                  through. (default: 0)
--trampoline-mpp-timeout <arg>                    Timeout in seconds before multipart htlcs that don't add up to the
                                                  payment amount are failed back to the sender. (default: 60)
--trampoline-cltv-delta <arg>                     The number of blocks between incoming payments and outgoing payments:
                                                  this needs to be enough to make sure that if we have to, we can close
                                                  the outgoing payment before the incoming, or redeem the incoming once
                                                  the outgoing is redeemed. (default: 34)

Testing

To run all tests call make test, or PYTEST_PAR=7 make test -j3.

Unit tests

To run only the unit tests call make utest.

Integration tests

Prerequisites

In order to run the integration tests you need

• python >= 3.8, < 4.0
• virtualenv (python -m pip install --user virtualenv)
• lightningd accessible through your PATH
• bitcoind and bitcoin-cli accessible through your PATH

Running integration tests

Call make itest to only run the integration tests. To run a single test, use PYTEST_OPTS="-k name_of_test" make itest. To run tests in parallel, use PYTEST_PAR=7 make itest.

Contributing

Contributions are welcome! Make sure to run make check before committing, or PYTEST_PAR=7 make check -j6 if you like to be fast.