multi: add Bitcoin Cash

client/asset/bch/bch.go

@@ -0,0 +1,265 @@
+// This code is available on the terms of the project LICENSE.md file,
+// also available online at https://blueoakcouncil.org/license/1.0.0.
+
+package bch
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"math"
+
+	"decred.org/dcrdex/client/asset"
+	"decred.org/dcrdex/client/asset/btc"
+	"decred.org/dcrdex/dex"
+	dexbch "decred.org/dcrdex/dex/networks/bch"
+	dexbtc "decred.org/dcrdex/dex/networks/btc"
+	"github.com/btcsuite/btcd/btcec"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/gcash/bchd/bchec"
+	bchscript "github.com/gcash/bchd/txscript"
+	bchwire "github.com/gcash/bchd/wire"
+)
+
+const (
+	// BipID is the Bip 44 coin ID for Bitcoin Cash.
+	BipID = 145
+	// The default fee is passed to the user as part of the asset.WalletInfo
+	// structure.
+	defaultFee        = 100
+	minNetworkVersion = 221100
+)
+
+var (
+	fallbackFeeKey = "fallbackfee"
+	configOpts     = []*asset.ConfigOption{
+		{
+			Key:         "walletname",
+			DisplayName: "Wallet Name",
+			Description: "The wallet name",
+		},
+		{
+			Key:         "rpcuser",
+			DisplayName: "JSON-RPC Username",
+			Description: "Bitcoin Cash 'rpcuser' setting",
+		},
+		{
+			Key:         "rpcpassword",
+			DisplayName: "JSON-RPC Password",
+			Description: "Bitcoin Cash 'rpcpassword' setting",
+			NoEcho:      true,
+		},
+		{
+			Key:         "rpcbind",
+			DisplayName: "JSON-RPC Address",
+			Description: "<addr> or <addr>:<port> (default 'localhost')",
+		},
+		{
+			Key:         "rpcport",
+			DisplayName: "JSON-RPC Port",
+			Description: "Port for RPC connections (if not set in Address)",
+		},
+		{
+			Key:          fallbackFeeKey,
+			DisplayName:  "Fallback fee rate",
+			Description:  "Bitcoin Cash 'fallbackfee' rate. Units: BCH/kB",
+			DefaultValue: defaultFee * 1000 / 1e8,
+		},
+		{
+			Key:         "txsplit",
+			DisplayName: "Pre-split funding inputs",
+			Description: "When placing an order, create a \"split\" transaction to fund the order without locking more of the wallet balance than " +
+				"necessary. Otherwise, excess funds may be reserved to fund the order until the first swap contract is broadcast " +
+				"during match settlement, or the order is canceled. This an extra transaction for which network mining fees are paid. " +
+				"Used only for standing-type orders, e.g. limit orders without immediate time-in-force.",
+			IsBoolean: true,
+		},
+	}
+	// WalletInfo defines some general information about a Bitcoin Cash wallet.
+	WalletInfo = &asset.WalletInfo{
+		Name:  "Bitcoin Cash",
+		Units: "Satoshi",
+		// Same as bitcoin. That's dumb.
+		DefaultConfigPath: dexbtc.SystemConfigPath("bitcoin"),
+		ConfigOpts:        configOpts,
+	}
+)
+
+func init() {
+	asset.Register(BipID, &Driver{})
+}
+
+// Driver implements asset.Driver.
+type Driver struct{}
+
+// Setup creates the BCH exchange wallet. Start the wallet with its Run method.
+func (d *Driver) Setup(cfg *asset.WalletConfig, logger dex.Logger, network dex.Network) (asset.Wallet, error) {
+	return NewWallet(cfg, logger, network)
+}
+
+// DecodeCoinID creates a human-readable representation of a coin ID for
+// Bitcoin Cash.
+func (d *Driver) DecodeCoinID(coinID []byte) (string, error) {
+	// Bitcoin Cash and Bitcoin have the same tx hash and output format.
+	return (&btc.Driver{}).DecodeCoinID(coinID)
+}
+
+// Info returns basic information about the wallet and asset.
+func (d *Driver) Info() *asset.WalletInfo {
+	return WalletInfo
+}
+
+// NewWallet is the exported constructor by which the DEX will import the
+// exchange wallet. The wallet will shut down when the provided context is
+// canceled. The configPath can be an empty string, in which case the standard
+// system location of the daemon config file is assumed.
+func NewWallet(cfg *asset.WalletConfig, logger dex.Logger, network dex.Network) (asset.Wallet, error) {
+	var params *chaincfg.Params
+	switch network {
+	case dex.Mainnet:
+		params = dexbch.MainNetParams
+	case dex.Testnet:
+		params = dexbch.TestNet3Params
+	case dex.Regtest:
+		params = dexbch.RegressionNetParams
+	default:
+		return nil, fmt.Errorf("unknown network ID %v", network)
+	}
+
+	// Designate the clone ports. These will be overwritten by any explicit
+	// settings in the configuration file. Bitcoin Cash uses the same default
+	// ports as Bitcoin.
+	ports := dexbtc.NetPorts{
+		Mainnet: "8332",
+		Testnet: "18332",
+		Simnet:  "18443",
+	}
+	cloneCFG := &btc.BTCCloneCFG{
+		WalletCFG:          cfg,
+		MinNetworkVersion:  minNetworkVersion,
+		WalletInfo:         WalletInfo,
+		Symbol:             "bch",
+		Logger:             logger,
+		Network:            network,
+		ChainParams:        params,
+		Ports:              ports,
+		DefaultFallbackFee: defaultFee,
+		Segwit:             false,
+		LegacyBalance:      true,
+		// Bitcoin Cash uses the Cash Address encoding, which is Bech32, but
+		// not indicative of segwit. We provide a custom encoder.
+		AddressDecoder: dexbch.DecodeCashAddress,
+		// Bitcoin Cash has a custom signature hash algorithm. Since they don't
+		// have segwit, Bitcoin Cash implemented a variation of the withdrawn
+		// BIP0062 that utilizes Shnorr signatures.
+		// https://gist.github.com/markblundeberg/a3aba3c9d610e59c3c49199f697bc38b#making-unmalleable-smart-contracts
+		// https://github.com/bitcoin/bips/blob/master/bip-0062.mediawiki
+		NonSegwitSigner: rawTxInSigner,
+		// The old allowHighFees bool argument to sendrawtransaction.
+		ArglessChangeAddrRPC: true,
+		// Bitcoin Cash uses estimatefee instead of estimatesmartfee, and even
+		// then, they modified it from the old Bitcoin Core estimatefee by
+		// removing the confirmation target argument.
+		FeeEstimator: estimateFee,
+	}
+
+	xcWallet, err := btc.BTCCloneWallet(cloneCFG)
+	if err != nil {
+		return nil, err
+	}
+
+	return &BCHWallet{
+		ExchangeWallet: xcWallet,
+	}, nil
+}
+
+// BCHWallet embeds btc.ExchangeWallet, but re-implements a couple of methods to
+// perform on-the-fly address translation.
+type BCHWallet struct {
+	*btc.ExchangeWallet
+}
+
+// Address converts the Bitcoin base58-encoded address returned by the embedded
+// ExchangeWallet into a Cash Address.
+func (bch *BCHWallet) Address() (string, error) {
+	btcAddrStr, err := bch.ExchangeWallet.Address()
+	if err != nil {
+		return "", err
+	}
+	return dexbch.RecodeCashAddress(btcAddrStr, bch.Net())
+}
+
+// AuditContract modifies the *asset.Contract returned by the ExchangeWallet
+// AuditContract method by converting the Recipient to the Cash Address
+// encoding.
+func (bch *BCHWallet) AuditContract(coinID, contract dex.Bytes) (*asset.AuditInfo, error) { // AuditInfo has address
+	ai, err := bch.ExchangeWallet.AuditContract(coinID, contract)
+	if err != nil {
+		return nil, err
+	}
+	ai.Recipient, err = dexbch.RecodeCashAddress(ai.Recipient, bch.Net())
+	if err != nil {
+		return nil, err
+	}
+	return ai, nil
+}
+
+// rawTxSigner signs the transaction using Bitcoin Cash's custom signature
+// hash and signing algorithm.
+func rawTxInSigner(btcTx *wire.MsgTx, idx int, subScript []byte, hashType txscript.SigHashType, btcKey *btcec.PrivateKey, val uint64) ([]byte, error) {
+	bchTx, err := translateTx(btcTx)
+	if err != nil {
+		return nil, fmt.Errorf("btc->bch wire.MsgTx translation error: %v", err)
+	}
+
+	bchKey, _ := bchec.PrivKeyFromBytes(bchec.S256(), btcKey.Serialize())
+
+	return bchscript.RawTxInECDSASignature(bchTx, idx, subScript, bchscript.SigHashType(uint32(hashType)), bchKey, int64(val))
+}
+
+// serializeBtcTx serializes the wire.MsgTx.
+func serializeBtcTx(msgTx *wire.MsgTx) ([]byte, error) {
+	buf := bytes.NewBuffer(make([]byte, 0, msgTx.SerializeSize()))
+	err := msgTx.Serialize(buf)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
+// estimateFee uses Bitcoin Cash's estimatefee RPC, since estimatesmartfee
+// is not implemented.
+func estimateFee(ctx context.Context, node btc.RawRequester, confTarget uint64) (uint64, error) {
+	resp, err := node.RawRequest(ctx, "estimatefee", nil)
+	if err != nil {
+		return 0, err
+	}
+	var feeRate float64
+	err = json.Unmarshal(resp, &feeRate)
+	if err != nil {
+		return 0, err
+	}
+	if feeRate <= 0 {
+		return 0, fmt.Errorf("fee could not be estimated")
+	}
+	return uint64(math.Round(feeRate * 1e5)), nil
+}
+
+// translateTx converts the btcd/*wire.MsgTx into a bchd/*wire.MsgTx.
+func translateTx(btcTx *wire.MsgTx) (*bchwire.MsgTx, error) {
+	txB, err := serializeBtcTx(btcTx)
+	if err != nil {
+		return nil, err
+	}
+
+	bchTx := bchwire.NewMsgTx(bchwire.TxVersion)
+	err = bchTx.Deserialize(bytes.NewBuffer(txB))
+	if err != nil {
+		return nil, err
+	}
+
+	return bchTx, nil
+}

client/asset/bch/regnet_test.go

@@ -0,0 +1,40 @@
+// +build harness
+
+package bch
+
+// Regnet tests expect the BCH test harness to be running.
+//
+// Sim harness info:
+// The harness has three wallets, alpha, beta, and gamma.
+// All three wallets have confirmed UTXOs.
+// The beta wallet has only coinbase outputs.
+// The alpha wallet has coinbase outputs too, but has sent some to the gamma
+//   wallet, so also has some change outputs.
+// The gamma wallet has regular transaction outputs of varying size and
+// confirmation count. Value:Confirmations =
+// 10:8, 18:7, 5:6, 7:5, 1:4, 15:3, 3:2, 25:1
+
+import (
+	"testing"
+
+	"decred.org/dcrdex/client/asset/btc/livetest"
+	"decred.org/dcrdex/dex"
+	dexbtc "decred.org/dcrdex/dex/networks/btc"
+)
+
+const alphaAddress = "bchreg:qqnm4z2tftyyeu3kvzzepmlp9mj3g6fvxgft570vll"
+
+var tBCH = &dex.Asset{
+	ID:           2,
+	Symbol:       "bch",
+	SwapSize:     dexbtc.InitTxSize,
+	SwapSizeBase: dexbtc.InitTxSizeBase,
+	MaxFeeRate:   10,
+	LotSize:      1e6,
+	RateStep:     10,
+	SwapConf:     1,
+}
+
+func TestWallet(t *testing.T) {
+	livetest.Run(t, NewWallet, alphaAddress, tBCH, false)
+}