loop/swapserverrpc/instantout.proto

syntax = "proto3";

// We can't change this to swapserverrpc, it would be a breaking change because
// the package name is also contained in the HTTP URIs and old clients would
// call the wrong endpoints. Luckily with the go_package option we can have
// different golang and RPC package names to fix protobuf namespace conflicts.
package looprpc;

option go_package = "github.com/lightninglabs/loop/swapserverrpc";

service InstantSwapServer {
    // RequestInstantLoopOut initiates an instant loop out swap.
    rpc RequestInstantLoopOut (InstantLoopOutRequest)
        returns (InstantLoopOutResponse);

    // PollPaymentAccepted polls the server to see if the payment has been
    // accepted.
    rpc PollPaymentAccepted (PollPaymentAcceptedRequest)
        returns (PollPaymentAcceptedResponse);

    // InitHtlcSig is called by the client to initiate the htlc sig exchange.
    rpc InitHtlcSig (InitHtlcSigRequest) returns (InitHtlcSigResponse);

    // PushHtlcSig is called by the client to push the htlc sigs to the server.
    rpc PushHtlcSig (PushHtlcSigRequest) returns (PushHtlcSigResponse);

    // PushPreimage is called by the client to push the preimage to the server.
    // This returns the musig2 signatures that the client needs to sweep the
    // htlc.
    rpc PushPreimage (PushPreimageRequest) returns (PushPreimageResponse);

    // CancelInstantSwap tries to cancel the instant swap. This can only be
    // called if the swap has not been accepted yet.
    rpc CancelInstantSwap (CancelInstantSwapRequest)
        returns (CancelInstantSwapResponse);

    // GetInstantOutQuote returns the absolute fee in satoshis for the swap and
    // the pubkey to query the route to estimate offchain payment fees.
    rpc GetInstantOutQuote (GetInstantOutQuoteRequest)
        returns (GetInstantOutQuoteResponse);
}

message InstantLoopOutRequest {
    // Htlc related fields:
    // The key for the htlc preimage spending path.
    bytes receiver_key = 1;

    // The hash of the preimage that will be used to settle the htlc.
    bytes swap_hash = 2;

    // The requested absolute block height of the on-chain htlc.
    int32 expiry = 3;

    // The fee rate in sat/kw that should be used for the htlc.
    uint64 htlc_fee_rate = 4;

    // The reservations used as the inputs.
    repeated bytes reservation_ids = 5;

    // The protocol version to use for the swap.
    InstantOutProtocolVersion protocol_version = 6;
}

message InstantLoopOutResponse {
    // The swap invoice that the client should pay.
    string swap_invoice = 1;

    // the key for the htlc expiry path.
    bytes sender_key = 2;
};

message PollPaymentAcceptedRequest {
    // The hash of the swap invoice.
    bytes swap_hash = 1;
}

message PollPaymentAcceptedResponse {
    // Whether the payment has been accepted.
    bool accepted = 1;
}

message InitHtlcSigRequest {
    // The hash of the swap invoice.
    bytes swap_hash = 1;

    // The nonces that the client will use to generate the htlc sigs.
    repeated bytes htlc_client_nonces = 2;
}

message InitHtlcSigResponse {
    // The nonces that the server will use to generate the htlc sigs.
    repeated bytes htlc_server_nonces = 2;
}

message PushHtlcSigRequest {
    // The hash of the swap invoice.
    bytes swap_hash = 1;

    // The sigs that the client generated for the reservation inputs.
    repeated bytes client_sigs = 2;
}

message PushHtlcSigResponse {
    // The sigs that the server generated for the reservation inputs.
    repeated bytes server_sigs = 1;
}

message PushPreimageRequest {
    // The preimage that the client generated for the swap.
    bytes preimage = 1;

    // The nonces that the client used to generate the sweepless sweep sigs.
    repeated bytes client_nonces = 2;

    // The address that the client wants to sweep the htlc to.
    string client_sweep_addr = 3;

    // The fee rate in sat/kw that the client wants to use for the sweep.
    uint64 musig_tx_fee_rate = 4;
}

message PushPreimageResponse {
    // The sweep sigs that the server generated for the htlc.
    repeated bytes musig2_sweep_sigs = 1;

    // The nonces that the server used to generate the sweepless sweep sigs.
    repeated bytes server_nonces = 2;
}

message CancelInstantSwapRequest {
    // The hash of the swap invoice.
    bytes swap_hash = 1;
}

message CancelInstantSwapResponse {
}

message GetInstantOutQuoteRequest {
    // The amount to swap in satoshis.
    uint64 amount = 1;
}

message GetInstantOutQuoteResponse {
    // The swap fee in satoshis.
    uint64 swap_fee = 1;
}

enum InstantOutProtocolVersion {
    INSTANTOUT_NONE = 0;
    INSTANTOUT_FULL_RESERVATION = 1;
};