lightning-sendonion -- Send a payment with a custom onion packet
sendonion onion first_hop payment_hash [label] [shared_secrets] [partid] [bolt11] [amount_msat] [destination]
The sendonion RPC command can be used to initiate a payment attempt with a custom onion packet. The onion packet is used to deliver instructions for hops along the route on how to behave. Normally these instructions are indications on where to forward a payment and what parameters to use, or contain details of the payment for the final hop. However, it is possible to add arbitrary information for hops in the custom onion, allowing for custom extensions that are not directly supported by Core Lightning.
The onion is specific to the route that is being used and the payment_hash
used to construct, and therefore cannot be reused for other payments or to
attempt a separate route. The custom onion can generally be created using the
devtools/onion CLI tool, or the createonion RPC command.
The onion parameter is a hex-encoded 1366 bytes long blob that was returned by either of the tools that can generate onions. It contains the payloads destined for each hop and some metadata. Please refer to BOLT 04 for further details.
The first_hop parameter instructs Core Lightning which peer to send the onion
to. It is a JSON dictionary that corresponds to the first element of the route
array returned by getroute. The following is a minimal example telling
Core Lightning to use any available channel to
to add an HTLC for 1002 millisatoshis and a delay of 21 blocks on top of the current blockheight:
If the first element of route does not have "channel" set, a suitable channel (if any) will be chosen, otherwise that specific short-channel-id is used.
The payment_hash parameter specifies the 32 byte hex-encoded hash to use as a challenge to the HTLC that we are sending. It is specific to the onion and has to match the one the onion was created with.
The label parameter can be used to provide a human readable reference to retrieve the payment at a later time.
The shared_secrets parameter is a JSON list of 32 byte hex-encoded secrets
that were used when creating the onion. Core Lightning can send a payment with a
custom onion without the knowledge of these secrets, however it will not be
able to parse an eventual error message since that is encrypted with the
shared secrets used in the onion. If shared_secrets is provided Core Lightning
will decrypt the error, act accordingly, e.g., add a
in the error to its network view, and set the details in listsendpays
correctly. If it is not provided Core Lightning will store the encrypted onion,
and expose it in listsendpays allowing the caller to decrypt it
externally. The following is an example of a 3 hop onion:
If shared_secrets is not provided the Core Lightning node does not know how long the route is, which channels or nodes are involved, and what an eventual error could have been. It can therefore be used for oblivious payments.
The partid value, if provided and non-zero, allows for multiple parallel partial payments with the same payment_hash.
The bolt11 parameter, if provided, will be returned in waitsendpay and listsendpays results.
The destination parameter, if provided, will be returned in listpays result.
The amount_msat parameter is used to annotate the payment, and is returned by waitsendpay and listsendpays.
On success, an object is returned, containing:
- id (u64): unique ID for this payment attempt
- payment_hash (hash): the hash of the payment_preimage which will prove payment
- status (string): status of the payment (could be complete if already sent previously) (one of "pending", "complete")
- created_at (u64): the UNIX timestamp showing when this payment was initiated
- amount_sent_msat (msat): The amount sent
- amount_msat (msat, optional): The amount delivered to destination (if known)
- destination (pubkey, optional): the final destination of the payment if known
- label (string, optional): the label, if given to sendpay
- bolt11 (string, optional): the bolt11 string (if supplied)
- bolt12 (string, optional): the bolt12 string (if supplied: experimental-offers only).
- partid (u64, optional): the partid (if supplied) to sendonion/sendpay
If status is "complete":
- payment_preimage (secret): the proof of payment: SHA256 of this payment_hash
If status is "pending":
- message (string, optional): Monitor status with listpays or waitsendpay
If shared_secrets was provided and an error was returned by one of the intermediate nodes the error details are decrypted and presented here. Otherwise the error code is 202 for an unparseable onion.
Christian Decker <email@example.com> is mainly responsible.
lightning-createonion(7), lightning-sendpay(7), lightning-listsendpays(7)
Main web site: https://github.com/ElementsProject/lightning