core,btc,app: Manage SPV wallet peers

This change allows the user to see the peers the BTC SPV wallets are
connected to, and add new peers.
- `client/asset`: Adds a new `PeerManager` interface with three methods:
  `Peers`, `AddPeer` and `RemovePeer`. Wallets that implement this
  interface have the trait `WalletTraitPeerManager`.
- `client/core`: Adds new methods that call the `PeerManager` methods.
- `client/btc`:
  - A `SPVPeerManager` type is added which manages a key value db and a
    neutrino chain service. When the user adds a new peer, it is stored
    in the key value db, and will be automatically connected the next
    time the wallet is opened.
  - The `BTCWallet` interface now has three new functions,  `Peers`,
    `AddPeer` and `RemovePeer`, and the BTC, BCH, and LTC SPV wallets
    each use a `SPVPeerManager` in order to handle these new functions.

client/asset/bch/spv.go

@@ -8,6 +8,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
 	"os"
 	"path/filepath"
 	"sync/atomic"
@@ -35,6 +36,7 @@ import (
 	"github.com/gcash/bchd/bchec"
 	bchchaincfg "github.com/gcash/bchd/chaincfg"
 	bchchainhash "github.com/gcash/bchd/chaincfg/chainhash"
+	"github.com/gcash/bchd/peer"
 	bchtxscript "github.com/gcash/bchd/txscript"
 	bchwire "github.com/gcash/bchd/wire"
 	"github.com/gcash/bchlog"
@@ -83,13 +85,15 @@ type bchSPVWallet struct {
 	cl          *neutrino.ChainService
 	loader      *wallet.Loader
 	neutrinoDB  walletdb.DB
+
+	peerManager *btc.SPVPeerManager
 }
 
 var _ btc.BTCWallet = (*bchSPVWallet)(nil)
 
 // openSPVWallet creates a bchSPVWallet, but does not Start.
 // Satisfies btc.BTCWalletConstructor.
-func openSPVWallet(dir string, cfg *btc.WalletConfig, btcParams *chaincfg.Params, log dex.Logger) btc.BTCWallet {
+func openSPVWallet(dir string, cfg *btc.WalletConfig, btcParams *chaincfg.Params, log dex.Logger) (btc.BTCWallet, error) {
 	var bchParams *bchchaincfg.Params
 	switch btcParams.Name {
 	case dexbch.MainNetParams.Name:
@@ -108,7 +112,7 @@ func openSPVWallet(dir string, cfg *btc.WalletConfig, btcParams *chaincfg.Params
 		allowAutomaticRescan: !cfg.ActivelyUsed,
 	}
 	w.birthdayV.Store(cfg.AdjustedBirthday())
-	return w
+	return w, nil
 }
 
 // createSPVWallet creates a new SPV wallet.
@@ -197,32 +201,13 @@ func (w *bchSPVWallet) Start() (btc.SPVService, error) {
 	}
 	errCloser.Add(w.neutrinoDB.Close)
 
-	// Depending on the network, we add some addpeers or a connect peer. On
-	// regtest, if the peers haven't been explicitly set, add the simnet harness
-	// alpha node as an additional peer so we don't have to type it in. On
-	// mainet and testnet4, add a known reliable persistent peer to be used in
-	// addition to normal DNS seed-based peer discovery.
-	var addPeers []string
-	var connectPeers []string
-	switch w.chainParams.Net {
-	// case bchwire.MainNet:
-	// 	addPeers = []string{"cfilters.ssgen.io"}
-	case bchwire.TestNet4:
-		// Add the address for a local bchd testnet4 node.
-		addPeers = []string{"localhost:28333"}
-	case bchwire.TestNet, bchwire.SimNet: // plain "wire.TestNet" is regnet!
-		connectPeers = []string{"localhost:21577"}
-	}
-
 	w.log.Debug("Starting neutrino chain service...")
 	w.cl, err = neutrino.NewChainService(neutrino.Config{
 		DataDir:     w.dir,
 		Database:    w.neutrinoDB,
 		ChainParams: *w.chainParams,
 		// https://github.com/gcash/neutrino/pull/36
 		PersistToDisk: true, // keep cfilter headers on disk for efficient rescanning
-		AddPeers:      addPeers,
-		ConnectPeers:  connectPeers,
 		// WARNING: PublishTransaction currently uses the entire duration
 		// because if an external bug, but even if the bug is resolved, a
 		// typical inv/getdata round trip is ~4 seconds, so we set this so
@@ -254,6 +239,22 @@ func (w *bchSPVWallet) Start() (btc.SPVService, error) {
 		w.ForceRescan()
 	}
 
+	var defaultPeers []string
+	switch w.chainParams.Net {
+	// case bchwire.MainNet:
+	// 	addPeers = []string{"cfilters.ssgen.io"}
+	case bchwire.TestNet4:
+		// Add the address for a local bchd testnet4 node.
+		defaultPeers = []string{"localhost:28333"}
+	case bchwire.TestNet, bchwire.SimNet: // plain "wire.TestNet" is regnet!
+		defaultPeers = []string{"localhost:21577"}
+	}
+	peerManager, err := btc.NewSPVPeerManager(&spvService{w.cl}, defaultPeers, w.dir, w.log)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create peer manager: %w", err)
+	}
+	w.peerManager = peerManager
+
 	if err = w.chainClient.Start(); err != nil { // lazily starts connmgr
 		return nil, fmt.Errorf("couldn't start Neutrino client: %v", err)
 	}
@@ -263,6 +264,8 @@ func (w *bchSPVWallet) Start() (btc.SPVService, error) {
 
 	errCloser.Success()
 
+	w.peerManager.ConnectToInitialWalletPeers()
+
 	return &spvService{w.cl}, nil
 }
 
@@ -746,6 +749,18 @@ func (w *bchSPVWallet) updateDBBirthday(bday time.Time) error {
 	})
 }
 
+func (w *bchSPVWallet) Peers() ([]*asset.WalletPeer, error) {
+	return w.peerManager.Peers()
+}
+
+func (w *bchSPVWallet) AddPeer(addr string) error {
+	return w.peerManager.AddPeer(addr)
+}
+
+func (w *bchSPVWallet) RemovePeer(addr string) error {
+	return w.peerManager.RemovePeer(addr)
+}
+
 // secretSource is used to locate keys and redemption scripts while signing a
 // transaction. secretSource satisfies the txauthor.SecretsSource interface.
 type secretSource struct {
@@ -834,6 +849,21 @@ func (s *spvService) Peers() []btc.SPVPeer {
 	return peers
 }
 
+func (s *spvService) AddPeer(addr string) error {
+	serverPeer := neutrino.NewServerPeer(s.ChainService, true)
+	peer, err := peer.NewOutboundPeer(neutrino.NewPeerConfig(serverPeer), addr)
+	if err != nil {
+		return err
+	}
+	conn, err := net.Dial("tcp", peer.Addr())
+	if err != nil {
+		return err
+	}
+	peer.AssociateConnection(conn)
+	serverPeer.Peer = peer
+	return nil
+}
+
 func (s *spvService) GetBlockHeight(h *chainhash.Hash) (int32, error) {
 	return s.ChainService.GetBlockHeight((*bchchainhash.Hash)(h))
 }

client/asset/btc/btc.go

@@ -854,6 +854,7 @@ var _ asset.Rescanner = (*ExchangeWalletSPV)(nil)
 var _ asset.FeeRater = (*ExchangeWalletFullNode)(nil)
 var _ asset.LogFiler = (*ExchangeWalletSPV)(nil)
 var _ asset.Recoverer = (*ExchangeWalletSPV)(nil)
+var _ asset.PeerManager = (*ExchangeWalletSPV)(nil)
 var _ asset.TxFeeEstimator = (*intermediaryWallet)(nil)
 
 // RecoveryCfg is the information that is transferred from the old wallet
@@ -909,6 +910,26 @@ func (btc *ExchangeWalletSPV) Rescan(_ context.Context) error {
 	return w.wallet.RescanAsync()
 }
 
+// Peers returns a list of peers that the wallet is connected to.
+func (btc *ExchangeWalletSPV) Peers() ([]*asset.WalletPeer, error) {
+	w := btc.node.(*spvWallet)
+	return w.peers()
+}
+
+// AddPeer connects the wallet to a new peer. The peer's address will be
+// persisted and connected to each time the wallet is started up.
+func (btc *ExchangeWalletSPV) AddPeer(addr string) error {
+	w := btc.node.(*spvWallet)
+	return w.addPeer(addr)
+}
+
+// RemovePeer will remove a peer that was added by AddPeer. This peer may
+// still be connected to by the wallet if it discovers it on it's own.
+func (btc *ExchangeWalletSPV) RemovePeer(addr string) error {
+	w := btc.node.(*spvWallet)
+	return w.removePeer(addr)
+}
+
 // FeeRate satisfies asset.FeeRater.
 func (btc *ExchangeWalletFullNode) FeeRate() uint64 {
 	rate, err := btc.estimateFee(btc.node, 1)
@@ -1187,7 +1208,10 @@ func OpenSPVWallet(cfg *BTCCloneCFG, walletConstructor BTCWalletConstructor) (*E
 		decodeAddr:  btc.decodeAddr,
 	}
 
-	spvw.wallet = walletConstructor(spvw.dir, spvw.cfg, spvw.chainParams, spvw.log)
+	spvw.wallet, err = walletConstructor(spvw.dir, spvw.cfg, spvw.chainParams, spvw.log)
+	if err != nil {
+		return nil, err
+	}
 
 	btc.node = spvw
 

client/asset/btc/spv.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
 	"os"
 	"path/filepath"
 	"sync/atomic"
@@ -52,6 +53,8 @@ type btcSPVWallet struct {
 	// rescanStarting is set while reloading the wallet and dropping
 	// transactions from the wallet db.
 	rescanStarting uint32 // atomic
+
+	peerManager *SPVPeerManager
 }
 
 var _ BTCWallet = (*btcSPVWallet)(nil)
@@ -113,7 +116,7 @@ func createSPVWallet(privPass []byte, seed []byte, bday time.Time, dataDir strin
 
 // openSPVWallet is the BTCWalletConstructor for Bitcoin.
 func openSPVWallet(dir string, cfg *WalletConfig,
-	chainParams *chaincfg.Params, log dex.Logger) BTCWallet {
+	chainParams *chaincfg.Params, log dex.Logger) (BTCWallet, error) {
 
 	w := &btcSPVWallet{
 		dir:                  dir,
@@ -122,7 +125,7 @@ func openSPVWallet(dir string, cfg *WalletConfig,
 		allowAutomaticRescan: !cfg.ActivelyUsed,
 	}
 	w.birthdayV.Store(cfg.AdjustedBirthday())
-	return w
+	return w, nil
 }
 
 func (w *btcSPVWallet) Birthday() time.Time {
@@ -174,40 +177,41 @@ func (w *btcSPVWallet) Start() (SPVService, error) {
 	}
 	errCloser.Add(w.neutrinoDB.Close)
 
-	// Depending on the network, we add some addpeers or a connect peer. On
-	// regtest, if the peers haven't been explicitly set, add the simnet harness
-	// alpha node as an additional peer so we don't have to type it in. On
-	// mainet and testnet3, add a known reliable persistent peer to be used in
-	// addition to normal DNS seed-based peer discovery.
-	var addPeers []string
-	var connectPeers []string
-	switch w.chainParams.Net {
-	case wire.MainNet:
-		addPeers = []string{"cfilters.ssgen.io"}
-	case wire.TestNet3:
-		addPeers = []string{"dex-test.ssgen.io"}
-	case wire.TestNet, wire.SimNet: // plain "wire.TestNet" is regnet!
-		connectPeers = []string{"localhost:20575"}
-	}
 	w.log.Debug("Starting neutrino chain service...")
 	w.cl, err = neutrino.NewChainService(neutrino.Config{
 		DataDir:       w.dir,
 		Database:      w.neutrinoDB,
 		ChainParams:   *w.chainParams,
 		PersistToDisk: true, // keep cfilter headers on disk for efficient rescanning
-		AddPeers:      addPeers,
-		ConnectPeers:  connectPeers,
+		// AddPeers:      addPeers,
+		// ConnectPeers:  connectPeers,
 		// WARNING: PublishTransaction currently uses the entire duration
 		// because if an external bug, but even if the resolved, a typical
 		// inv/getdata round trip is ~4 seconds, so we set this so neutrino does
 		// not cancel queries too readily.
 		BroadcastTimeout: 6 * time.Second,
+		NameResolver:     net.LookupIP,
 	})
 	if err != nil {
-		return nil, fmt.Errorf("couldn't create Neutrino ChainService: %v", err)
+		return nil, fmt.Errorf("couldn't create Neutrino ChainService: %w", err)
 	}
 	errCloser.Add(w.cl.Stop)
 
+	var defaultPeers []string
+	switch w.chainParams.Net {
+	case wire.MainNet:
+		defaultPeers = []string{"cfilters.ssgen.io:8333"}
+	case wire.TestNet3:
+		defaultPeers = []string{"dex-test.ssgen.io:18333"}
+	case wire.TestNet, wire.SimNet: // plain "wire.TestNet" is regnet!
+		defaultPeers = []string{"localhost:20575"}
+	}
+	peerManager, err := NewSPVPeerManager(&btcChainService{w.cl}, defaultPeers, w.dir, w.log)
+	if err != nil {
+		return nil, fmt.Errorf("failed to create peer manager: %w", err)
+	}
+	w.peerManager = peerManager
+
 	w.chainClient = chain.NewNeutrinoClient(w.chainParams, w.cl)
 	w.Wallet = btcw
 
@@ -238,6 +242,8 @@ func (w *btcSPVWallet) Start() (SPVService, error) {
 
 	errCloser.Success()
 
+	w.peerManager.ConnectToInitialWalletPeers()
+
 	return &btcChainService{w.cl}, nil
 }
 
@@ -434,6 +440,18 @@ func (w *btcSPVWallet) BlockNotifications(ctx context.Context) <-chan *BlockNoti
 	return ch
 }
 
+func (w *btcSPVWallet) AddPeer(addr string) error {
+	return w.peerManager.AddPeer(addr)
+}
+
+func (w *btcSPVWallet) RemovePeer(addr string) error {
+	return w.peerManager.RemovePeer(addr)
+}
+
+func (w *btcSPVWallet) Peers() ([]*asset.WalletPeer, error) {
+	return w.peerManager.Peers()
+}
+
 // secretSource is used to locate keys and redemption scripts while signing a
 // transaction. secretSource satisfies the txauthor.SecretsSource interface.
 type secretSource struct {