lwk: add TLS support for Electrum

Add TLS support for Electrum.
In default, the scheme is a tls connection,
which allows connection to electrs.
context timeout for wallet operations to enhance reliability.

cmd/peerswap-plugin/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"errors"
 	"fmt"
 	glog "log"
@@ -209,22 +210,33 @@ func run(ctx context.Context, lightningPlugin *clightning.ClightningClient) erro
 		log.Infof("Liquid swaps enabled")
 	} else if config.LWK != nil && config.LWK.Enabled() {
 		liquidEnabled = true
-		ec, err2 := electrum.NewClientTCP(ctx, config.LWK.GetElectrumEndpoint())
-		if err2 != nil {
-			return err2
+		var ec *electrum.Client
+		if config.LWK.IsElectrumWithTLS() {
+			ec, err = electrum.NewClientSSL(ctx, config.LWK.GetElectrumEndpoint(), &tls.Config{
+				MinVersion: tls.VersionTLS12,
+			})
+			if err != nil {
+				return err
+			}
+		} else {
+			ec, err = electrum.NewClientTCP(ctx, config.LWK.GetElectrumEndpoint())
+			if err != nil {
+				return err
+			}
 		}
-		liquidRpcWallet, err2 = lwk.NewLWKRpcWallet(lwk.NewLwk(config.LWK.GetLWKEndpoint()),
+		liquidRpcWallet, err = lwk.NewLWKRpcWallet(lwk.NewLwk(config.LWK.GetLWKEndpoint()),
 			ec, config.LWK.GetWalletName(), config.LWK.GetSignerName())
-		if err2 != nil {
-			return err2
+		if err != nil {
+			return err
 		}
 		liquidTxWatcher, err = lwk.NewElectrumTxWatcher(ec)
 		if err != nil {
 			return err
 		}
 		liquidOnChainService = onchain.NewLiquidOnChain(liquidRpcWallet, config.LWK.GetChain())
 		supportedAssets = append(supportedAssets, "lbtc")
-		log.Infof("Liquid swaps enabled")
+		log.Infof("Liquid swaps enabled with LWK. Network: %s, wallet: %s",
+			config.LWK.GetNetwork(), config.LWK.GetWalletName())
 	} else {
 		log.Infof("Liquid swaps disabled")
 	}

cmd/peerswaplnd/peerswapd/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"context"
+	"crypto/tls"
 	"errors"
 	"fmt"
 	"io"
@@ -231,11 +232,20 @@ func run() error {
 			liquidOnChainService = onchain.NewLiquidOnChain(liquidRpcWallet, liquidChain)
 		} else if cfg.LWKConfig.Enabled() {
 			log.Infof("Liquid swaps enabled with LWK. Network: %s, wallet: %s", cfg.LWKConfig.GetNetwork(), cfg.LWKConfig.GetWalletName())
-			ec, err := electrum.NewClientTCP(ctx, cfg.LWKConfig.GetElectrumEndpoint())
-			if err != nil {
-				return err
+			var ec *electrum.Client
+			if cfg.LWKConfig.IsElectrumWithTLS() {
+				ec, err = electrum.NewClientSSL(ctx, cfg.LWKConfig.GetElectrumEndpoint(), &tls.Config{
+					MinVersion: tls.VersionTLS12,
+				})
+				if err != nil {
+					return err
+				}
+			} else {
+				ec, err = electrum.NewClientTCP(ctx, cfg.LWKConfig.GetElectrumEndpoint())
+				if err != nil {
+					return err
+				}
 			}
-
 			// This call is blocking, waiting for elements to come alive and sync.
 			liquidRpcWallet, err = lwk.NewLWKRpcWallet(lwk.NewLwk(cfg.LWKConfig.GetLWKEndpoint()),
 				ec, cfg.LWKConfig.GetWalletName(), cfg.LWKConfig.GetSignerName())

lwk/conf_builder.go

@@ -19,14 +19,14 @@ func (b *confBuilder) DefaultConf() (*confBuilder, error) {
 	switch b.network {
 	case NetworkTestnet:
 		lwkEndpoint = "http://localhost:32111"
-		electrumEndpoint = "tcp://blockstream.info:465"
+		electrumEndpoint = "ssl://blockstream.info:465"
 	case NetworkRegtest:
 		lwkEndpoint = "http://localhost:32112"
 		electrumEndpoint = "tcp://localhost:60401"
 	default:
 		// mainnet is the default port
 		lwkEndpoint = "http://localhost:32110"
-		electrumEndpoint = "tcp://blockstream.info:995"
+		electrumEndpoint = "ssl://blockstream.info:995"
 	}
 	lwkURL, err := NewConfURL(lwkEndpoint)
 	if err != nil {

lwk/config.go

@@ -32,6 +32,10 @@ func (c *Conf) GetElectrumEndpoint() string {
 	return c.electrumEndpoint.Host
 }
 
+func (c *Conf) IsElectrumWithTLS() bool {
+	return c.electrumEndpoint.Scheme == "ssl"
+}
+
 func (c *Conf) GetNetwork() string {
 	return c.network.String()
 }

lwk/lwkwallet.go

@@ -6,6 +6,7 @@ import (
 	"log"
 	"math"
 	"strings"
+	"time"
 
 	"github.com/checksum0/go-electrum/electrum"
 
@@ -24,6 +25,10 @@ const (
 	minimumSatPerByte SatPerKVByte = 0.1
 	// 1 kb = 1000 bytes
 	kb float64 = 1000
+	// TODO: Basically, the inherited ctx should be used
+	// and there is no need to specify a timeout here.
+	// Set up here because ctx is not inherited throughout the current codebase.
+	defaultContextTimeout = time.Second * 5
 )
 
 // LWKRpcWallet uses the elementsd rpc wallet
@@ -47,7 +52,9 @@ func NewLWKRpcWallet(lwkClient *lwkclient, electrumClient *electrum.Client, wall
 		lwkClient:      lwkClient,
 		electrumClient: electrumClient,
 	}
-	err := rpcWallet.setupWallet(context.Background())
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
+	err := rpcWallet.setupWallet(ctx)
 	if err != nil {
 		return nil, err
 	}
@@ -111,7 +118,8 @@ func (r *LWKRpcWallet) createWallet(ctx context.Context, walletName, signerName
 // CreateFundedTransaction takes a tx with outputs and adds inputs in order to spend the tx
 func (r *LWKRpcWallet) CreateAndBroadcastTransaction(swapParams *swap.OpeningParams,
 	asset []byte) (txid, rawTx string, fee Satoshi, err error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	feerate := float64(r.getFeePerKb(ctx)) * kb
 	fundedTx, err := r.lwkClient.send(ctx, &sendRequest{
 		Addressees: []*unvalidatedAddressee{
@@ -149,7 +157,8 @@ func (r *LWKRpcWallet) CreateAndBroadcastTransaction(swapParams *swap.OpeningPar
 
 // GetBalance returns the balance in sats
 func (r *LWKRpcWallet) GetBalance() (Satoshi, error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	balance, err := r.lwkClient.balance(ctx, &balanceRequest{
 		WalletName: r.walletName,
 	})
@@ -161,7 +170,8 @@ func (r *LWKRpcWallet) GetBalance() (Satoshi, error) {
 
 // GetAddress returns a new blech32 address
 func (r *LWKRpcWallet) GetAddress() (string, error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	address, err := r.lwkClient.address(ctx, &addressRequest{
 		WalletName: r.walletName})
 	if err != nil {
@@ -172,7 +182,8 @@ func (r *LWKRpcWallet) GetAddress() (string, error) {
 
 // SendToAddress sends an amount to an address
 func (r *LWKRpcWallet) SendToAddress(address string, amount Satoshi) (string, error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	sendres, err := r.lwkClient.send(ctx, &sendRequest{
 		WalletName: r.walletName,
 		Addressees: []*unvalidatedAddressee{
@@ -204,7 +215,8 @@ func (r *LWKRpcWallet) SendToAddress(address string, amount Satoshi) (string, er
 }
 
 func (r *LWKRpcWallet) SendRawTx(txHex string) (string, error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	res, err := r.electrumClient.BroadcastTransaction(ctx, txHex)
 	if err != nil {
 		return "", err
@@ -225,7 +237,8 @@ func (r *LWKRpcWallet) getFeePerKb(ctx context.Context) SatPerKVByte {
 }
 
 func (r *LWKRpcWallet) GetFee(txSize int64) (Satoshi, error) {
-	ctx := context.Background()
+	ctx, cancel := context.WithTimeout(context.Background(), defaultContextTimeout)
+	defer cancel()
 	// assume largest witness
 	fee := r.getFeePerKb(ctx) * float64(txSize)
 	return Satoshi(fee), nil