feat: 2-hop swaps (u→m→v) + channel_adjacency poll hint

Makefile

@@ -177,7 +177,7 @@ test-matrix-bitcoin_mixed: test-bins
 
 .PHONY: test-matrix-bitcoin_lndlnd
 test-matrix-bitcoin_lndlnd: test-bins
-	${INTEGRATION_TEST_ENV} go test ${INTEGRATION_TEST_OPTS} -run '^Test_Swap(In|Out)Matrix/(bitcoin_lndlnd).*$$' ./test
+	${INTEGRATION_TEST_ENV} go test ${INTEGRATION_TEST_OPTS} -run '^(Test_Swap(In|Out)Matrix/(bitcoin_lndlnd).*|Test_2Hop_Bitcoin_LND.*)$$' ./test
 
 .PHONY: test-matrix-liquid_clncln
 test-matrix-liquid_clncln: test-bins

clightning/clightning.go

@@ -8,6 +8,7 @@ import (
 	"fmt"
 	log2 "log"
 	"os"
+	"sort"
 	"time"
 
 	"github.com/btcsuite/btcd/chaincfg"
@@ -198,6 +199,7 @@ type PeerChannel struct {
 	PeerConnected    bool              `json:"peer_connected"`
 	State            string            `json:"state"`
 	ShortChannelId   string            `json:"short_channel_id,omitempty"`
+	Private          bool              `json:"private,omitempty"`
 	TotalMsat        glightning.Amount `json:"total_msat,omitempty"`
 	ToUsMsat         glightning.Amount `json:"to_us_msat,omitempty"`
 	ReceivableMsat   glightning.Amount `json:"receivable_msat,omitempty"`
@@ -294,6 +296,55 @@ func (cl *ClightningClient) ReceivableMsat(scid string) (uint64, error) {
 	return 0, fmt.Errorf("could not find a channel with scid: %s", scid)
 }
 
+func (cl *ClightningClient) ChannelsToPeer(peerPubkey string) ([]string, error) {
+	var res ListPeerChannelsResponse
+	err := cl.glightning.Request(ListPeerChannelsRequest{Id: peerPubkey}, &res)
+	if err != nil {
+		return nil, err
+	}
+
+	var scids []string
+	for _, ch := range res.Channels {
+		if ch.PeerId != peerPubkey || ch.ShortChannelId == "" {
+			continue
+		}
+		if err := cl.checkChannel(ch); err != nil {
+			continue
+		}
+		scids = append(scids, lightning.Scid(ch.ShortChannelId).ClnStyle())
+	}
+	sort.Strings(scids)
+	return scids, nil
+}
+
+func (cl *ClightningClient) ListChannels(ctx context.Context) ([]peersync.Channel, error) {
+	var res ListPeerChannelsResponse
+	if err := cl.glightning.Request(ListPeerChannelsRequest{}, &res); err != nil {
+		return nil, err
+	}
+
+	channels := make([]peersync.Channel, 0, len(res.Channels))
+	for _, ch := range res.Channels {
+		if ch.PeerId == "" || ch.ShortChannelId == "" {
+			continue
+		}
+		peerID, err := peersync.NewPeerID(ch.PeerId)
+		if err != nil {
+			continue
+		}
+
+		channels = append(channels, peersync.Channel{
+			Peer:           peerID,
+			ChannelID:      0,
+			ShortChannelID: lightning.Scid(ch.ShortChannelId).ClnStyle(),
+			Active:         ch.PeerConnected && ch.State == "CHANNELD_NORMAL",
+			Public:         !ch.Private,
+		})
+	}
+
+	return channels, nil
+}
+
 // checkChannel performs a set of sanity checks id the channel is eligible for
 // a swap of amtSat
 func (cl *ClightningClient) checkChannel(ch PeerChannel) error {
@@ -503,6 +554,66 @@ func (cl *ClightningClient) PayInvoiceViaChannel(payreq string, scid string) (pr
 	return preimage, nil
 }
 
+func (cl *ClightningClient) PayInvoiceVia2HopRoute(payreq string, outgoingScid string, incomingScid string, intermediaryPubkey string) (preimage string, err error) {
+	bolt11, err := cl.glightning.DecodeBolt11(payreq)
+	if err != nil {
+		return "", err
+	}
+
+	if bolt11.AmountMsat.MSat() == 0 {
+		return "", fmt.Errorf("invoice has no amount")
+	}
+
+	outgoingScid = lightning.Scid(outgoingScid).ClnStyle()
+	incomingScid = lightning.Scid(incomingScid).ClnStyle()
+
+	route, err := cl.glightning.GetRoute(
+		bolt11.Payee,
+		bolt11.AmountMsat.MSat(),
+		10.0,
+		uint(bolt11.MinFinalCltvExpiry+1),
+		"",
+		0.0001,
+		nil,
+		2,
+	)
+	if err != nil {
+		return "", err
+	}
+
+	if len(route) != 2 {
+		return "", fmt.Errorf("could not find 2-hop route")
+	}
+	if route[0].Id != intermediaryPubkey {
+		return "", fmt.Errorf("route does not use expected intermediary")
+	}
+	if route[0].ShortChannelId != outgoingScid || route[1].ShortChannelId != incomingScid {
+		return "", fmt.Errorf("route does not use expected channels")
+	}
+
+	label := randomString()
+	_, err = cl.glightning.SendPay(
+		route,
+		bolt11.PaymentHash,
+		label,
+		bolt11.AmountMsat.MSat(),
+		payreq,
+		bolt11.PaymentSecret,
+		0,
+	)
+	if err != nil {
+		return "", err
+	}
+
+	res, err := cl.glightning.WaitSendPay(bolt11.PaymentHash, 0)
+	if err != nil {
+		return "", err
+	}
+
+	preimage = res.PaymentPreimage
+	return preimage, nil
+}
+
 // RebalancePayment handles the lightning payment that should re-balance the
 // channel.
 func (cl *ClightningClient) RebalancePayment(payreq string, channel string) (preimage string, err error) {

clightning/clightning_commands.go

@@ -180,6 +180,7 @@ type SwapOut struct {
 	Asset               string            `json:"asset"`
 	PremiumLimitRatePPM int64             `json:"premium_rate_limit_ppm"`
 	Force               bool              `json:"force"`
+	PeerPubkey          string            `json:"peer_pubkey,omitempty"`
 	cl                  *ClightningClient `json:"-"`
 }
 
@@ -227,14 +228,20 @@ func (l *SwapOut) Call() (jrpc2.Result, error) {
 		return nil, errors.New("fundingChannels is not connected")
 	}
 
+	intermediaryPeerId := fundingChannels.Id
+	peerId := intermediaryPeerId
+	if l.PeerPubkey != "" {
+		peerId = l.PeerPubkey
+	}
+
 	// Skip this check when `force` is set.
 	if !l.Force {
-		if l.cl.peerSync == nil || !l.cl.peerSync.HasCompatiblePeer(fundingChannels.Id) {
+		if l.cl.peerSync == nil || !l.cl.peerSync.HasCompatiblePeer(peerId) {
 			return nil, fmt.Errorf("peer does not run peerswap")
 		}
 	}
 
-	if !l.cl.isPeerConnected(fundingChannels.Id) {
+	if !l.cl.isPeerConnected(peerId) {
 		return nil, fmt.Errorf("peer is not connected")
 	}
 
@@ -255,7 +262,12 @@ func (l *SwapOut) Call() (jrpc2.Result, error) {
 	}
 
 	pk := l.cl.GetNodeId()
-	swapOut, err := l.cl.swaps.SwapOut(fundingChannels.Id, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM)
+	var swapOut *swap.SwapStateMachine
+	if l.PeerPubkey != "" && l.PeerPubkey != intermediaryPeerId {
+		swapOut, err = l.cl.swaps.SwapOutTwoHop(peerId, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM, intermediaryPeerId)
+	} else {
+		swapOut, err = l.cl.swaps.SwapOut(peerId, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -302,6 +314,7 @@ type SwapIn struct {
 	Asset               string            `json:"asset"`
 	PremiumLimitRatePPM int64             `json:"premium_limit_ppm"`
 	Force               bool              `json:"force"`
+	PeerPubkey          string            `json:"peer_pubkey,omitempty"`
 	cl                  *ClightningClient `json:"-"`
 }
 
@@ -349,14 +362,20 @@ func (l *SwapIn) Call() (jrpc2.Result, error) {
 		return nil, errors.New("fundingChannels is not connected")
 	}
 
+	intermediaryPeerId := fundingChannels.Id
+	peerId := intermediaryPeerId
+	if l.PeerPubkey != "" {
+		peerId = l.PeerPubkey
+	}
+
 	// Skip this check when `force` is set.
 	if !l.Force {
-		if l.cl.peerSync == nil || !l.cl.peerSync.HasCompatiblePeer(fundingChannels.Id) {
+		if l.cl.peerSync == nil || !l.cl.peerSync.HasCompatiblePeer(peerId) {
 			return nil, fmt.Errorf("peer does not run peerswap")
 		}
 	}
 
-	if !l.cl.isPeerConnected(fundingChannels.Id) {
+	if !l.cl.isPeerConnected(peerId) {
 		return nil, fmt.Errorf("peer is not connected")
 	}
 	switch l.Asset {
@@ -373,7 +392,12 @@ func (l *SwapIn) Call() (jrpc2.Result, error) {
 	}
 
 	pk := l.cl.GetNodeId()
-	swapIn, err := l.cl.swaps.SwapIn(fundingChannels.Id, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM)
+	var swapIn *swap.SwapStateMachine
+	if l.PeerPubkey != "" && l.PeerPubkey != intermediaryPeerId {
+		swapIn, err = l.cl.swaps.SwapInTwoHop(peerId, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM, intermediaryPeerId)
+	} else {
+		swapIn, err = l.cl.swaps.SwapIn(peerId, l.Asset, l.ShortChannelId, pk, l.SatAmt, l.PremiumLimitRatePPM)
+	}
 	if err != nil {
 		return nil, err
 	}
@@ -586,6 +610,7 @@ func (l *ListPeers) Call() (jrpc2.Result, error) {
 
 			view := format.BuildPeerView(peer.Id, capability, swaps)
 			peerSwapPeer := peerswaprpc.NewPeerSwapPeerFromView(view)
+			peerSwapPeer.ChannelAdjacency = peerswaprpc.ChannelAdjacencyFromPeerState(peerState)
 			channels, err := l.cl.glightning.ListChannelsBySource(peer.Id)
 			if err != nil {
 				return nil, err

clightning/options.go

@@ -10,7 +10,7 @@ const (
 	liquidRpcUserOption             = "peerswap-elementsd-rpcuser"
 	liquidRpcPasswordOption         = "peerswap-elementsd-rpcpassword"
 	liquidRpcPasswordFilepathOption = "peerswap-elementsd-rpcpasswordfile"
-	liquidSwapsOption             = "peerswap-elementsd-swaps"
+	liquidSwapsOption               = "peerswap-elementsd-swaps"
 	liquidRpcWalletOption           = "peerswap-elementsd-rpcwallet"
 
 	bitcoinRpcHostOption     = "peerswap-bitcoin-rpchost"
@@ -53,7 +53,7 @@ type PeerswapClightningConfig struct {
 	LiquidRpcHost         string `json:"liquid.rpchost"`
 	LiquidRpcPort         uint   `json:"liquid.rpcport"`
 	LiquidRpcWallet       string `json:"liquid.rpcwallet"`
-	LiquidSwaps         bool   `json:"liquid.swaps"`
+	LiquidSwaps           bool   `json:"liquid.swaps"`
 
 	LWKSignerName    string `json:"lwksignername"`
 	LWKWalletName    string `json:"lwkwalletname"`

cmd/peerswaplnd/pscli/main.go

@@ -75,6 +75,11 @@ var (
 		Name:     "peer_pubkey",
 		Required: true,
 	}
+	swapPeerPubkeyFlag = cli.StringFlag{
+		Name:     "peer_pubkey",
+		Usage:    "swap negotiation peer pubkey (optional; set for 2-hop swaps)",
+		Required: false,
+	}
 	PremiumLimitRatePPMFlag = cli.Uint64Flag{
 		Name:     "premium_limit_rate_ppm",
 		Usage:    "premium limit for a swap in parts per million",
@@ -104,6 +109,7 @@ var (
 			channelIdFlag,
 			assetFlag,
 			PremiumLimitRatePPMFlag,
+			swapPeerPubkeyFlag,
 		},
 		Action: swapOut,
 	}
@@ -116,6 +122,7 @@ var (
 			channelIdFlag,
 			assetFlag,
 			PremiumLimitRatePPMFlag,
+			swapPeerPubkeyFlag,
 		},
 		Action: swapIn,
 	}
@@ -291,6 +298,7 @@ func swapIn(ctx *cli.Context) error {
 		SwapAmount:          ctx.Uint64(satAmountFlag.Name),
 		Asset:               ctx.String(assetFlag.Name),
 		PremiumLimitRatePpm: ctx.Int64(PremiumLimitRatePPMFlag.Name),
+		PeerPubkey:          ctx.String(swapPeerPubkeyFlag.Name),
 	})
 	if err != nil {
 		return err
@@ -312,6 +320,7 @@ func swapOut(ctx *cli.Context) error {
 		SwapAmount:          ctx.Uint64(satAmountFlag.Name),
 		Asset:               ctx.String(assetFlag.Name),
 		PremiumLimitRatePpm: ctx.Int64(PremiumLimitRatePPMFlag.Name),
+		PeerPubkey:          ctx.String(swapPeerPubkeyFlag.Name),
 	})
 	if err != nil {
 		return err