client: Allow Firo to send to an EXX address.

	EXX addresses are used for Firo and other privacy coins to
	send funds to  Binance and other exchanges due to last US
	administration regulations.

Author: dev-warrior777

client/asset/btc/btc.go

@@ -364,6 +364,10 @@ type BTCCloneCFG struct {
 	// into an address string. If AddressStringer is not supplied, the
 	// (btcutil.Address).String method will be used.
 	AddressStringer dexbtc.AddressStringer // btcutil.Address => string, may be an override or just the String method
+	// PayToAddressScript is an optional argument that can make non-standard tx
+	// outputs. If PayToAddressScript is not supplied the (txscript).PayToAddrScript
+	// method will be used. Note the extra paramaeter for a string address.
+	PayToAddressScript func(btcutil.Address, string) ([]byte, error)
 	// BlockDeserializer can be used in place of (*wire.MsgBlock).Deserialize.
 	BlockDeserializer func([]byte) (*wire.MsgBlock, error)
 	// ArglessChangeAddrRPC can be true if the getrawchangeaddress takes no
@@ -801,6 +805,7 @@ type baseWallet struct {
 	localFeeRate      func(context.Context, RawRequester, uint64) (uint64, error)
 	feeCache          *feeRateCache
 	decodeAddr        dexbtc.AddressDecoder
+	payToAddress      func(btcutil.Address, string) ([]byte, error)
 	walletDir         string
 
 	deserializeTx func([]byte) (*wire.MsgTx, error)
@@ -1317,6 +1322,13 @@ func newUnconnectedWallet(cfg *BTCCloneCFG, walletCfg *WalletConfig) (*baseWalle
 		}
 	}
 
+	addressPayer := cfg.PayToAddressScript
+	if addressPayer == nil {
+		addressPayer = func(addr btcutil.Address, _ string) ([]byte, error) {
+			return txscript.PayToAddrScript(addr)
+		}
+	}
+
 	w := &baseWallet{
 		symbol:            cfg.Symbol,
 		chainParams:       cfg.ChainParams,
@@ -1336,6 +1348,7 @@ func newUnconnectedWallet(cfg *BTCCloneCFG, walletCfg *WalletConfig) (*baseWalle
 		feeCache:          feeCache,
 		decodeAddr:        addrDecoder,
 		stringAddr:        addrStringer,
+		payToAddress:      addressPayer,
 		walletInfo:        cfg.WalletInfo,
 		deserializeTx:     txDeserializer,
 		serializeTx:       txSerializer,
@@ -4505,7 +4518,7 @@ func (btc *baseWallet) send(address string, val uint64, feeRate uint64, subtract
 	if err != nil {
 		return nil, 0, 0, fmt.Errorf("invalid address: %s", address)
 	}
-	pay2script, err := txscript.PayToAddrScript(addr)
+	pay2script, err := btc.payToAddress(addr, address)
 	if err != nil {
 		return nil, 0, 0, fmt.Errorf("PayToAddrScript error: %w", err)
 	}

client/asset/firo/exx.go

@@ -0,0 +1,64 @@
+package firo
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/btcsuite/btcd/btcutil"
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/txscript"
+	"github.com/btcsuite/btcutil/base58"
+)
+
+const (
+	PKH_LEN                    = 20
+	MAINNET_VER_BYTE_PKH       = 0x52
+	MAINNET_VER_BYTE_EXX       = 0x01
+	TESTNET_VER_BYTE_PKH       = 0x41
+	TESTNET_VER_BYTE_EXT       = 0x01
+	ALLNETS_EXTRA_BYTE_EX_ONE  = 0xb9 // python: ADDRTYPE_EXP2PKH
+	MAINNET_EXTRA_BYTE_EXX_TWO = 0xbb
+	TESTNET_EXTRA_BYTE_EXT_TWO = 0xb1
+
+	EXCHANGE_MARKER_BYTE = 0xe0 // python: OP_EXCHANGEADDR
+	SCRIPT_LEN           = 26
+)
+
+func isExxAddress(address string) bool {
+	return strings.HasPrefix(address, "EXX") || strings.HasPrefix(address, "EXT")
+}
+
+// decodeExxAddress decodes a Firo exchange address.
+func decodeExxAddress(encodedAddr string, net *chaincfg.Params) (btcutil.Address, error) {
+	decoded, _, err := base58.CheckDecode(encodedAddr)
+	if err != nil {
+		return nil, err
+	}
+	// pull out the pkh - Mainnet: (ver=0x01)   <0xb9> <0xbb> <PKH>
+	decLen := len(decoded)
+	if decLen < PKH_LEN+1 {
+		return nil, fmt.Errorf("bad decoded len %d", decLen)
+	}
+	decExtra := decLen - PKH_LEN
+	pkh := decoded[decExtra:]
+
+	addrPKH, err := btcutil.NewAddressPubKeyHash(pkh, net)
+	if err != nil {
+		return nil, err
+	}
+	return btcutil.Address(addrPKH), nil
+}
+
+func buildExxPayToScript(addr btcutil.Address, address string) ([]byte, error) {
+	if _, isPKH := addr.(*btcutil.AddressPubKeyHash); !isPKH {
+		return nil, fmt.Errorf("address %s does not contain a pubkey hash", address)
+	}
+	baseScript, err := txscript.PayToAddrScript(addr)
+	if err != nil {
+		return nil, err
+	}
+	script := make([]byte, 0, len(baseScript)+1)
+	script = append(script, EXCHANGE_MARKER_BYTE)
+	script = append(script, baseScript...)
+	return script, nil
+}

client/asset/firo/exx_test.go

@@ -0,0 +1,63 @@
+package firo
+
+import (
+	"bytes"
+	"encoding/hex"
+	"fmt"
+	"testing"
+
+	dexfiro "decred.org/dcrdex/dex/networks/firo"
+	"github.com/btcsuite/btcd/btcutil"
+)
+
+const (
+	exxAddress = "EXXKcAcVWXeG7S9aiXXGuGNZkWdB9XuSbJ1z"
+	decoded    = "386ed39285803b1782d0e363897f1a81a5b87421"
+	//            386ed39285803b1782d0e363897f1a81a5b87421
+	//  e0 76a914 386ed39285803b1782d0e363897f1a81a5b87421 88ac
+	// validateaddress firo-qt, electrum-firo just says 'true'
+	encodedAsPKH = "a5rrM1DY9XTRucbNrJQDtDc6GiEbcX7jRd"
+)
+
+func TestDecodeExxAddress(t *testing.T) {
+	addr, err := decodeExxAddress(exxAddress, dexfiro.MainNetParams)
+	if err != nil {
+		t.Fatalf("addr=%v - %v", addr, err)
+	}
+
+	switch ty := addr.(type) {
+	case btcutil.Address:
+		fmt.Printf("type=%T\n", ty)
+	default:
+		t.Fatalf("invalid type=%T", ty)
+	}
+
+	if !addr.IsForNet(dexfiro.MainNetParams) {
+		t.Fatalf("IsForNet failed")
+	}
+	decodedB, err := hex.DecodeString(decoded)
+	if err != nil {
+		t.Fatalf("hex decode error: %v", err)
+	}
+	if !bytes.Equal(addr.ScriptAddress(), decodedB) {
+		t.Fatalf("ScriptAddress failed")
+	}
+	s := addr.String()
+	if s != encodedAsPKH {
+		t.Fatalf("String failed expected %s got %s", encodedAsPKH, s)
+	}
+}
+
+func TestBuildExxPayToScript(t *testing.T) {
+	addr, err := decodeExxAddress(exxAddress, dexfiro.MainNetParams)
+	if err != nil {
+		t.Fatalf("addr=%v - %v", addr, err)
+	}
+	script, err := buildExxPayToScript(addr, exxAddress)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(script) != SCRIPT_LEN {
+		t.Fatalf("wrong script length - expected %d got %d", SCRIPT_LEN, len(script))
+	}
+}

client/asset/firo/firo.go

@@ -22,6 +22,7 @@ import (
 	"github.com/btcsuite/btcd/btcec/v2"
 	"github.com/btcsuite/btcd/btcutil"
 	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/txscript"
 )
 
 const (
@@ -168,6 +169,8 @@ func NewWallet(cfg *asset.WalletConfig, logger dex.Logger, network dex.Network)
 		AssetID:                  BipID,
 		FeeEstimator:             estimateFee,
 		ExternalFeeEstimator:     externalFeeRate,
+		AddressDecoder:           decodeAddress,
+		PayToAddressScript:       payToAddressScript,
 		PrivKeyFunc:              nil, // set only for walletTypeRPC below
 	}
 
@@ -195,6 +198,35 @@ func NewWallet(cfg *asset.WalletConfig, logger dex.Logger, network dex.Network)
 	}
 }
 
+/******************************************************************************
+                             Helper Functions
+******************************************************************************/
+
+// decodeAddress decodes a firo address. For normal transparent addresses this
+// just uses btcd: btcutil.DecodeAddress.
+func decodeAddress(address string, net *chaincfg.Params) (btcutil.Address, error) {
+	if isExxAddress(address) {
+		return decodeExxAddress(address, net)
+	}
+	decAddr, err := btcutil.DecodeAddress(address, net)
+	if err != nil {
+		return nil, err
+	}
+	if !decAddr.IsForNet(net) {
+		return nil, errors.New("wrong network")
+	}
+	return decAddr, nil
+}
+
+// payToAddressScript builds a P2PKH script for a Firo output. For normal transparent
+// addresses btcd: txscript.PayToAddrScript is used.
+func payToAddressScript(addr btcutil.Address, address string) ([]byte, error) {
+	if isExxAddress(address) {
+		return buildExxPayToScript(addr, address)
+	}
+	return txscript.PayToAddrScript(addr)
+}
+
 // rpcCaller is satisfied by ExchangeWalletFullNode (baseWallet), providing
 // direct RPC requests.
 type rpcCaller interface {

dex/testing/firo/README_ELECTRUM_HARNESSES.md

@@ -12,7 +12,7 @@ See Also: README_HARNESS.md
 ## 2. ElectrumX-Firo Test Harness
 
 The harness is a script named **electrumx.sh** which downloads a git repo
-containing a release version of ElectrumX-Firo server.
+containing a specific commit of ElectrumX-Firo server. No external releases.
 
 It requires **harness.sh** Firo chain server harness running.
 

dex/testing/firo/electrum.sh

@@ -22,7 +22,10 @@ export PROTOCOL_BUFFERS_PYTHON_IMPLEMENTATION=python
 SCRIPT_DIR=$(pwd)
 
 # Electrum-Firo Version 4.1.5.2
-COMMIT=a3f64386efc9069cae83e23c241331de6f418b2f
+# COMMIT=a3f64386efc9069cae83e23c241331de6f418b2f
+
+# Electrum-Firo Version 4.1.5.5
+COMMIT=b99e9594bddeecba82a2531bbf0769bd589f3a34
 
 GENESIS=a42b98f04cc2916e8adfb5d9db8a2227c4629bc205748ed2f33180b636ee885b # regtest
 RPCPORT=8001
@@ -56,15 +59,12 @@ fi
 
 git remote -v
 
-CURRENT_COMMIT=$(git rev-parse HEAD)
-if [ ! "${CURRENT_COMMIT}" == "${COMMIT}" ]; then
-    git fetch --depth 1 origin ${COMMIT}
-    git reset --hard FETCH_HEAD
-fi
+git fetch --depth 1 origin ${COMMIT}
+git reset --hard FETCH_HEAD
 
 if [ ! -d "${ELECTRUM_DIR}/venv" ]; then
     # The venv interpreter will be this python version, e.g. python3.10
-    python3 -m venv ${ELECTRUM_DIR}/venv
+    python3.7 -m venv ${ELECTRUM_DIR}/venv
 fi
 source ${ELECTRUM_DIR}/venv/bin/activate
 python --version

dex/testing/firo/electrumx.sh

@@ -16,7 +16,11 @@
 
 set -ex
 
-COMMIT=c0cdcc0dfcaa057058fd1ed281557dede924cd27
+# No external releases - just master
+# May 11, 2023
+# COMMIT=c0cdcc0dfcaa057058fd1ed281557dede924cd27
+#  Jul 8, 2024
+COMMIT=937e4bb3d8802317b64231844b698d8758029ca5
 
 ELECTRUMX_DIR=~/dextest/electrum/firo/server
 REPO_DIR=${ELECTRUMX_DIR}/electrumx-repo
@@ -53,7 +57,8 @@ export NET="regtest"
 export DB_ENGINE="leveldb"
 export DB_DIRECTORY="${DATA_DIR}"
 export DAEMON_URL="http://user:[email protected]:53768"    # harness:alpha:rpc
-export SERVICES="ssl://localhost:50002,rpc://"
+# export SERVICES="ssl://localhost:50002,rpc://"
+export SERVICES="tcp://localhost:50001,rpc://"
 export SSL_CERTFILE="${DATA_DIR}/ssl.cert"
 export SSL_KEYFILE="${DATA_DIR}/ssl.key"
 export PEER_DISCOVERY="off"

dex/testing/firo/harness.sh

@@ -76,7 +76,8 @@ cd ${NODES_ROOT} && tmux new-session -d -s $SESSION $SHELL
 # Write config files.
 ################################################################################
 echo "Writing node config files"
-# These config files aren't actually used here, but can be used by other programs.
+# These config files aren't actually used here, but can be used by other programs
+# such as loadbot.
 
 cat > "${ALPHA_DIR}/alpha.conf" <<EOF
 rpcuser=user

go.mod

@@ -84,6 +84,7 @@ require (
 	github.com/agl/ed25519 v0.0.0-20170116200512-5312a6153412 // indirect
 	github.com/beorn7/perks v1.0.1 // indirect
 	github.com/bits-and-blooms/bitset v1.10.0 // indirect
+	github.com/btcsuite/btcutil v1.0.2
 	github.com/btcsuite/btcwallet/wallet/txrules v1.2.1 // indirect
 	github.com/btcsuite/btcwallet/wallet/txsizes v1.2.4 // indirect
 	github.com/btcsuite/go-socks v0.0.0-20170105172521-4720035b7bfd // indirect

go.sum

@@ -145,6 +145,8 @@ github.com/btcsuite/btcd/chaincfg/chainhash v1.1.0/go.mod h1:7SFka0XMvUgj3hfZtyd
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f h1:bAs4lUbRJpnnkd9VhRV3jjAVU7DJVjMaK+IsvSeZvFo=
 github.com/btcsuite/btclog v0.0.0-20170628155309-84c8d2346e9f/go.mod h1:TdznJufoqS23FtqVCzL0ZqgP5MqXbb4fg/WgDys70nA=
 github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d/go.mod h1:+5NJ2+qvTyV9exUAL/rxXi3DcLg2Ts+ymUAY5y4NvMg=
+github.com/btcsuite/btcutil v1.0.2 h1:9iZ1Terx9fMIOtq1VrwdqfsATL9MC2l8ZrUY6YZ2uts=
+github.com/btcsuite/btcutil v1.0.2/go.mod h1:j9HUFwoQRsZL3V4n+qG+CUnEGHOarIxfC3Le2Yhbcts=
 github.com/btcsuite/btcwallet v0.16.10-0.20240815225602-6ecae9c12fde h1:NURMAR/mat4V2ZwZE/dXIu+pfHc3SKN/kvAcKlfs/CU=
 github.com/btcsuite/btcwallet v0.16.10-0.20240815225602-6ecae9c12fde/go.mod h1:X2xDre+j1QphTRo54y2TikUzeSvreL1t1aMXrD8Kc5A=
 github.com/btcsuite/btcwallet/wallet/txauthor v1.3.4 h1:poyHFf7+5+RdxNp5r2T6IBRD7RyraUsYARYbp/7t4D8=
@@ -1188,6 +1190,7 @@ golang.org/x/crypto v0.0.0-20190701094942-4def268fd1a4/go.mod h1:yigFU9vqHzYiE8U
 golang.org/x/crypto v0.0.0-20190820162420-60c769a6c586/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
 golang.org/x/crypto v0.0.0-20190923035154-9ee001bba392/go.mod h1:/lpIB1dKB+9EgE3H3cr1v9wB50oz8l4C4h62xy7jSTY=
 golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
+golang.org/x/crypto v0.0.0-20200115085410-6d4e4cb37c7d/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200221231518-2aa609cf4a9d/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
 golang.org/x/crypto v0.0.0-20201016220609-9e8e0b390897/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=