initial commit

2019-10-09 18:32:15 -04:00 · 2019-10-09 18:32:15 -04:00 · bdb049e215
commit bdb049e215
9 changed files with 376 additions and 0 deletions
--- a/README.md
+++ b/README.md
@ -0,0 +1,5 @@
+## Zcash Network Crawler
+
+This is a CoreDNS plugin that scrapes addresses of peers from a Zcash network. It's intended as a safer and more scalable replacement for the [zcash-seeder](https://github.com/zcash/zcash-seeder) project.
+
+It uses [btcsuite](https://github.com/btcsuite) for networking and [crawshaw/sqlite](https://crawshaw.io/blog/go-and-sqlite) for storing peer data.
--- a/go.mod
+++ b/go.mod
@ -0,0 +1,8 @@
+module github.com/gtank/coredns-zcash
+
+go 1.12
+
+require (
+	github.com/btcsuite/btcd v0.0.0-20190926002857-ba530c4abb35
+	github.com/pkg/errors v0.8.1
+)
--- a/go.sum
+++ b/go.sum
@ -0,0 +1,36 @@
+github.com/aead/siphash v1.0.1/go.mod h1:Nywa3cDsYNNK3gaciGTWPwHt0wlpNV15vwmswBAUSII=
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+github.com/btcsuite/btcd v0.0.0-20190926002857-ba530c4abb35/go.mod h1:3J08xEfcugPacsc34/LKRU2yO7YmuT8yt28J8k2+rrI=
+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 h1:yJzD/yFppdVCf6ApMkVy8cUxV0XrxdP9rVf6D87/Mng=
+github.com/btcsuite/btcutil v0.0.0-20190425235716-9e5f4b9a998d/go.mod h1:+5NJ2+qvTyV9exUAL/rxXi3DcLg2Ts+ymUAY5y4NvMg=
+github.com/btcsuite/go-socks v0.0.0-20170105172521-4720035b7bfd h1:R/opQEbFEy9JGkIguV40SvRY1uliPX8ifOvi6ICsFCw=
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+github.com/jrick/logrotate v1.0.0/go.mod h1:LNinyqDIJnpAur+b8yyulnQw/wDuN1+BYKlTRt3OuAQ=
+github.com/kkdai/bstream v0.0.0-20161212061736-f391b8402d23/go.mod h1:J+Gs4SYgM6CZQHDETBtE9HaSEkGmuNXF86RwHhHUvq4=
+github.com/onsi/ginkgo v1.6.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/ginkgo v1.7.0/go.mod h1:lLunBs/Ym6LB5Z9jYTR76FiuTmxDTDusOGeTQH+WWjE=
+github.com/onsi/gomega v1.4.3/go.mod h1:ex+gbHU/CVuBBDIJjb2X0qEXbFg53c61hWP/1CpauHY=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
+golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44 h1:9lP3x0pW80sDI6t1UMSLA4to18W7R7imwAI/sWS9S8Q=
+golang.org/x/crypto v0.0.0-20170930174604-9419663f5a44/go.mod h1:6SG95UA2DQfeDnfUPMdvaQW0Q7yPrPDi9nlGo2tz2b4=
+golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=
+gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7/go.mod h1:dt/ZhP58zS4L8KSrWDmTeBkI65Dw0HsyUHuEVlX15mw=
+gopkg.in/yaml.v2 v2.2.1/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
--- a/zcash/client.go
+++ b/zcash/client.go
@ -0,0 +1,148 @@
+package zcash
+
+import (
+	"log"
+	"net"
+	"os"
+	"sync"
+	"time"
+
+	"github.com/btcsuite/btcd/peer"
+	"github.com/btcsuite/btcd/wire"
+
+	"github.com/gtank/coredns-zcash/zcash/network"
+
+	"github.com/pkg/errors"
+)
+
+var defaultPeerConfig = &peer.Config{
+	UserAgentName:    "MagicBean",
+	UserAgentVersion: "2.0.7",
+	ChainParams:      nil,
+	Services:         0,
+	TrickleInterval:  time.Second * 10,
+	ProtocolVersion:  170009, // Blossom
+}
+
+var logger = log.New(os.Stdout, "zcash_client: ", log.Ldate|log.Ltime|log.Lshortfile|log.LUTC)
+
+type Seeder struct {
+	peer   *peer.Peer
+	config *peer.Config
+
+	handshakeComplete     chan *peer.Peer
+	handshakePendingPeers map[string]*peer.Peer
+	livePeers             map[string]*peer.Peer
+
+	// For mutating the above
+	peerState sync.RWMutex
+}
+
+func newSeederPeerConfig(magic network.Network, template *peer.Config) (*peer.Config, error) {
+	var newPeerConfig peer.Config
+
+	// Load the default values
+	if template != nil {
+		newPeerConfig = *template
+	}
+
+	params, err := network.GetNetworkParams(magic)
+	if err != nil {
+		return nil, errors.Wrap(err, "couldn't construct peer config")
+	}
+	newPeerConfig.ChainParams = params
+
+	return &newPeerConfig, nil
+}
+
+func (s *Seeder) OnVerAck(p *peer.Peer, msg *wire.MsgVerAck) {
+	s.peerState.RLock()
+	if s.handshakePendingPeers[p.Addr()] == nil {
+		logger.Printf("Got verack from unexpected peer %s", p.Addr())
+		s.peerState.RUnlock()
+		return
+	}
+	s.peerState.RUnlock()
+
+	logger.Printf("Handshake completed with new peer %s", p.Addr())
+
+	s.peerState.Lock()
+	delete(s.handshakePendingPeers, p.Addr())
+	s.livePeers[p.Addr()] = p
+	s.peerState.Unlock()
+
+	s.handshakeComplete <- p
+}
+
+func NewSeeder(network network.Network) (*Seeder, error) {
+	config, err := newSeederPeerConfig(network, defaultPeerConfig)
+	if err != nil {
+		return nil, errors.Wrap(err, "could not construct seeder")
+	}
+
+	newSeeder := Seeder{
+		config:                config,
+		handshakeComplete:     make(chan *peer.Peer, 1),
+		handshakePendingPeers: make(map[string]*peer.Peer),
+		livePeers:             make(map[string]*peer.Peer),
+	}
+
+	newSeeder.config.Listeners.OnVerAck = newSeeder.OnVerAck
+
+	return &newSeeder, nil
+}
+
+// ConnectToPeer attempts to connect to a peer on the default port at the
+// specified address. It returns either a live peer connection or an error.
+func (s *Seeder) ConnectToPeer(addr string) (*peer.Peer, error) {
+	connectionString := net.JoinHostPort(addr, s.config.ChainParams.DefaultPort)
+
+	p, err := peer.NewOutboundPeer(s.config, connectionString)
+	if err != nil {
+		return nil, errors.Wrap(err, "constructing outbound peer")
+	}
+
+	conn, err := net.Dial("tcp", p.Addr())
+	if err != nil {
+		return nil, errors.Wrap(err, "dialing new peer address")
+	}
+
+	s.peerState.Lock()
+	s.handshakePendingPeers[p.Addr()] = p
+	s.peerState.Unlock()
+
+	p.AssociateConnection(conn)
+
+	for {
+		select {
+		case verackPeer := <-s.handshakeComplete:
+			if verackPeer.Addr() == p.Addr() {
+				return p, nil
+			}
+		case <-time.After(time.Second * 1):
+			return nil, errors.New("peer handshake timed out")
+		}
+	}
+
+	panic("This should be unreachable")
+}
+
+func (s *Seeder) GracefulDisconnect() {
+	s.peerState.Lock()
+
+	for _, v := range s.handshakePendingPeers {
+		logger.Printf("Disconnecting from peer %s", v.Addr())
+		v.Disconnect()
+		v.WaitForDisconnect()
+	}
+	s.handshakePendingPeers = make(map[string]*peer.Peer)
+
+	for _, v := range s.livePeers {
+		logger.Printf("Disconnecting from peer %s", v.Addr())
+		v.Disconnect()
+		v.WaitForDisconnect()
+	}
+	s.livePeers = make(map[string]*peer.Peer)
+
+	s.peerState.Unlock()
+}
--- a/zcash/client_test.go
+++ b/zcash/client_test.go
@ -0,0 +1,44 @@
+package zcash
+
+import (
+	"testing"
+	"time"
+
+	"github.com/gtank/coredns-zcash/zcash/network"
+)
+
+func TestOutboundPeer(t *testing.T) {
+	regSeeder, err := NewSeeder(network.Regtest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = regSeeder.ConnectToPeer("127.0.0.1")
+	if err != nil {
+		t.Error(err)
+	}
+	regSeeder.GracefulDisconnect()
+}
+
+func TestOutboundPeerAsync(t *testing.T) {
+	regSeeder, err := NewSeeder(network.Regtest)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	done := make(chan struct{})
+	go func() {
+		_, err := regSeeder.ConnectToPeer("127.0.0.1")
+		if err != nil {
+			t.Fatal(err)
+		}
+		regSeeder.GracefulDisconnect()
+		done <- struct{}{}
+	}()
+
+	select {
+	case <-done:
+	case <-time.After(time.Second * 1):
+		t.Error("timed out")
+	}
+}
--- a/zcash/network/magic.go
+++ b/zcash/network/magic.go
@ -0,0 +1,58 @@
+package network
+
+import (
+	"encoding/binary"
+	"errors"
+)
+
+/// Network represents the byte sequences used to identify different Zcash networks.
+type Network uint32
+
+const (
+	// Mainnet identifies the Zcash mainnet
+	Mainnet Network = 0x6427e924
+	// Testnet identifies ECC's public testnet
+	Testnet Network = 0xbff91afa
+	// Regtest identifies the regression test network
+	Regtest Network = 0x5f3fe8aa
+)
+
+var (
+	ErrInvalidMagic = errors.New("invalid network magic")
+)
+
+// Marshal appends the 4-byte, little endian encoding of a network identifier
+// to the dst slice and returns the resulting slice. If there is sufficient room
+// in the dst slice, Marshal does not allocate.
+func (m Network) Marshal(dst []byte) (out []byte) {
+	if n := len(dst) + 4; cap(dst) >= n {
+		out = dst[:n]
+	} else {
+		out = make([]byte, n)
+		copy(out, dst)
+	}
+
+	binary.LittleEndian.PutUint32(out[len(dst):], uint32(m))
+	return
+}
+
+// Decode parses a valid network identifier from a byte slice. It
+// returns the identifier on success, zero and an error on failure.
+func Decode(data []byte) (Network, error) {
+	if len(data) != 4 {
+		return 0, ErrInvalidMagic
+	}
+
+	number := Network(binary.LittleEndian.Uint32(data))
+
+	switch number {
+	case Mainnet:
+		return Mainnet, nil
+	case Testnet:
+		return Testnet, nil
+	case Regtest:
+		return Regtest, nil
+	default:
+		return 0, ErrInvalidMagic
+	}
+}
--- a/zcash/network/magic_test.go
+++ b/zcash/network/magic_test.go
@ -0,0 +1,27 @@
+package network
+
+import (
+	"bytes"
+	"testing"
+)
+
+func TestMainnetMagic(t *testing.T) {
+	// Zcash mainnet, src/chainparams.cpp
+	var pchMessageStart [4]byte
+	pchMessageStart[0] = 0x24
+	pchMessageStart[1] = 0xe9
+	pchMessageStart[2] = 0x27
+	pchMessageStart[3] = 0x64
+
+	magicBytes := Mainnet.Marshal(nil)
+
+	if !bytes.Equal(magicBytes, pchMessageStart[:]) {
+		t.Error("encoding failed")
+	}
+
+	magic, err := Decode(pchMessageStart[:])
+
+	if err != nil || magic != Mainnet {
+		t.Error("decoding failed")
+	}
+}
--- a/zcash/network/params.go
+++ b/zcash/network/params.go
@ -0,0 +1,47 @@
+package network
+
+import (
+	"github.com/btcsuite/btcd/chaincfg"
+	"github.com/btcsuite/btcd/wire"
+	"github.com/pkg/errors"
+)
+
+var (
+	// These are not fully valid chainparams, but they'll do for a seeder.
+	regtestParams = chaincfg.Params{
+		Name:        "regtest",
+		Net:         wire.BitcoinNet(Regtest),
+		DefaultPort: "18344",
+	}
+
+	// These are not fully valid chainparams, but they'll do for a seeder.
+	mainnetParams = chaincfg.Params{
+		Name:        "mainnet",
+		Net:         wire.BitcoinNet(Mainnet),
+		DefaultPort: "8233",
+	}
+
+	// These are not fully valid chainparams, but they'll do for a seeder.
+	testnetParams = chaincfg.Params{
+		Name:        "testnet",
+		Net:         wire.BitcoinNet(Testnet),
+		DefaultPort: "18233",
+	}
+)
+
+func GetNetworkParams(magic Network) (*chaincfg.Params, error) {
+	var cfg chaincfg.Params
+
+	switch magic {
+	case Regtest:
+		cfg = regtestParams
+	case Mainnet:
+		cfg = mainnetParams
+	case Testnet:
+		cfg = testnetParams
+	default:
+		return nil, errors.Wrap(ErrInvalidMagic, "no network params")
+	}
+
+	return &cfg, nil
+}
--- a/zcash/storage.go
+++ b/zcash/storage.go
@ -0,0 +1,3 @@
+package zcash
+
+// sqlite storage: resultFn writes to resp buffer