Refactor of the Go node (#44)

* added headersOp for safely processing headers

* Better handling of protocol messages.

* housekeeping + cleanup tests

* Added more blockchain logic + unit tests

* fixed unreachable error.

* added structured logging for all (node) components.

* added relay flag + bumped version

Gopkg.lock

@@ -19,12 +19,36 @@
   revision = "346938d642f2ec3594ed81d874461961cd0faa76"
   version = "v1.1.0"
 
+[[projects]]
+  name = "github.com/go-kit/kit"
+  packages = ["log"]
+  revision = "4dc7be5d2d12881735283bcab7352178e190fc71"
+  version = "v0.6.0"
+
+[[projects]]
+  name = "github.com/go-logfmt/logfmt"
+  packages = ["."]
+  revision = "390ab7935ee28ec6b286364bba9b4dd6410cb3d5"
+  version = "v0.3.0"
+
+[[projects]]
+  name = "github.com/go-stack/stack"
+  packages = ["."]
+  revision = "259ab82a6cad3992b4e21ff5cac294ccb06474bc"
+  version = "v1.7.0"
+
 [[projects]]
   branch = "master"
   name = "github.com/golang/snappy"
   packages = ["."]
   revision = "553a641470496b2327abcac10b36396bd98e45c9"
 
+[[projects]]
+  branch = "master"
+  name = "github.com/kr/logfmt"
+  packages = ["."]
+  revision = "b84e30acd515aadc4b783ad4ff83aff3299bdfe0"
+
 [[projects]]
   name = "github.com/pmezard/go-difflib"
   packages = ["difflib"]
@@ -98,6 +122,6 @@
 [solve-meta]
   analyzer-name = "dep"
   analyzer-version = 1
-  inputs-digest = "069a738aa1487766b26f9efb8103d2ce0526d43c83049cb5b792f0edf91568de"
+  inputs-digest = "53597073e919ad7bf52895a19f8b8526d12d666862fb1d36b4a9756e0499da5a"
   solver-name = "gps-cdcl"
   solver-version = 1

Gopkg.toml

@@ -51,3 +51,7 @@
 [[constraint]]
   name = "github.com/stretchr/testify"
   version = "1.2.1"
+
+[[constraint]]
+  name = "github.com/go-kit/kit"
+  version = "0.6.0"

Makefile

@@ -19,7 +19,7 @@ push-tag:
 	git push origin ${BRANCH} --tags
 
 run: build
-	./bin/neo-go node -seed ${SEEDS} -tcp ${PORT}
+	./bin/neo-go node -seed ${SEEDS} -tcp ${PORT} --relay true
 
 test:
 	@go test ./... -cover

VERSION

@@ -1 +1 @@
-0.25.0
+0.26.0

cli/server/server.go

@@ -16,6 +16,7 @@ func NewCommand() cli.Command {
 		Flags: []cli.Flag{
 			cli.IntFlag{Name: "tcp"},
 			cli.IntFlag{Name: "rpc"},
+			cli.BoolFlag{Name: "relay, r"},
 			cli.StringFlag{Name: "seed"},
 			cli.BoolFlag{Name: "privnet, p"},
 			cli.BoolFlag{Name: "mainnet, m"},
@@ -25,12 +26,6 @@ func NewCommand() cli.Command {
 }
 
 func startServer(ctx *cli.Context) error {
-	opts := network.StartOpts{
-		Seeds: parseSeeds(ctx.String("seed")),
-		TCP:   ctx.Int("tcp"),
-		RPC:   ctx.Int("rpc"),
-	}
-
 	net := network.ModePrivNet
 	if ctx.Bool("testnet") {
 		net = network.ModeTestNet
@@ -39,8 +34,16 @@ func startServer(ctx *cli.Context) error {
 		net = network.ModeMainNet
 	}
 
-	s := network.NewServer(net)
+	cfg := network.Config{
-	s.Start(opts)
+		UserAgent: "/NEO-GO:0.26.0/",
+		ListenTCP: uint16(ctx.Int("tcp")),
+		Seeds:     parseSeeds(ctx.String("seed")),
+		Net:       net,
+		Relay:     ctx.Bool("relay"),
+	}
+
+	s := network.NewServer(cfg)
+	s.Start()
 	return nil
 }
 

main.go

@@ -0,0 +1,15 @@
+package main
+
+import (
+	"os"
+
+	log "github.com/go-kit/kit/log"
+)
+
+func main() {
+	logger := log.NewLogfmtLogger(log.NewSyncWriter(os.Stderr))
+	logger.Log("hello", true)
+
+	logger = log.With(logger, "module", "node")
+	logger.Log("foo", true)
+}

pkg/core/block.go

@@ -33,6 +33,9 @@ type BlockBase struct {
 	_ uint8 // padding
 	// Script used to validate the block
 	Script *transaction.Witness
+
+	// hash of this block, created when binary encoded.
+	hash util.Uint256
 }
 
 // DecodeBinary implements the payload interface.
@@ -68,19 +71,35 @@ func (b *BlockBase) DecodeBinary(r io.Reader) error {
 	}
 
 	b.Script = &transaction.Witness{}
-	return b.Script.DecodeBinary(r)
+	if err := b.Script.DecodeBinary(r); err != nil {
+		return err
+	}
+
+	// Make the hash of the block here so we dont need to do this
+	// again.
+	hash, err := b.createHash()
+	if err != nil {
+		return err
+	}
+	b.hash = hash
+	return nil
 }
 
-// Hash returns the hash of the block.
+// Hash return the hash of the block.
+func (b *BlockBase) Hash() util.Uint256 {
+	return b.hash
+}
+
+// createHash creates the hash of the block.
 // When calculating the hash value of the block, instead of calculating the entire block,
 // only first seven fields in the block head will be calculated, which are
 // version, PrevBlock, MerkleRoot, timestamp, and height, the nonce, NextMiner.
 // Since MerkleRoot already contains the hash value of all transactions,
 // the modification of transaction will influence the hash value of the block.
-func (b *BlockBase) Hash() (hash util.Uint256, err error) {
+func (b *BlockBase) createHash() (hash util.Uint256, err error) {
 	buf := new(bytes.Buffer)
 	if err = b.encodeHashableFields(buf); err != nil {
-		return
+		return hash, err
 	}
 
 	// Double hash the encoded fields.
@@ -92,15 +111,25 @@ func (b *BlockBase) Hash() (hash util.Uint256, err error) {
 // encodeHashableFields will only encode the fields used for hashing.
 // see Hash() for more information about the fields.
 func (b *BlockBase) encodeHashableFields(w io.Writer) error {
-	err := binary.Write(w, binary.LittleEndian, &b.Version)
+	if err := binary.Write(w, binary.LittleEndian, &b.Version); err != nil {
-	err = binary.Write(w, binary.LittleEndian, &b.PrevHash)
-	err = binary.Write(w, binary.LittleEndian, &b.MerkleRoot)
-	err = binary.Write(w, binary.LittleEndian, &b.Timestamp)
-	err = binary.Write(w, binary.LittleEndian, &b.Index)
-	err = binary.Write(w, binary.LittleEndian, &b.ConsensusData)
-	err = binary.Write(w, binary.LittleEndian, &b.NextConsensus)
-
 		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, &b.PrevHash); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, &b.MerkleRoot); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, &b.Timestamp); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, &b.Index); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, &b.ConsensusData); err != nil {
+		return err
+	}
+	return binary.Write(w, binary.LittleEndian, &b.NextConsensus)
 }
 
 // EncodeBinary implements the Payload interface
@@ -108,21 +137,16 @@ func (b *BlockBase) EncodeBinary(w io.Writer) error {
 	if err := b.encodeHashableFields(w); err != nil {
 		return err
 	}
-
-	// padding
 	if err := binary.Write(w, binary.LittleEndian, uint8(1)); err != nil {
 		return err
 	}
-
-	// script
 	return b.Script.EncodeBinary(w)
 }
 
 // Header holds the head info of a block
 type Header struct {
 	BlockBase
-	// fixed to 0
+	_ uint8 // padding fixed to 0
-	_ uint8 // padding
 }
 
 // Verify the integrity of the header
@@ -150,15 +174,12 @@ func (h *Header) EncodeBinary(w io.Writer) error {
 	if err := h.BlockBase.EncodeBinary(w); err != nil {
 		return err
 	}
-
-	// padding
 	return binary.Write(w, binary.LittleEndian, uint8(0))
 }
 
 // Block represents one block in the chain.
 type Block struct {
 	BlockBase
-	// transaction list
 	Transactions []*transaction.Transaction
 }
 
@@ -205,11 +226,10 @@ func (b *Block) DecodeBinary(r io.Reader) error {
 	lentx := util.ReadVarUint(r)
 	b.Transactions = make([]*transaction.Transaction, lentx)
 	for i := 0; i < int(lentx); i++ {
-		tx := &transaction.Transaction{}
+		b.Transactions[i] = &transaction.Transaction{}
-		if err := tx.DecodeBinary(r); err != nil {
+		if err := b.Transactions[i].DecodeBinary(r); err != nil {
 			return err
 		}
-		b.Transactions[i] = tx
 	}
 
 	return nil

pkg/core/block_test.go

@@ -8,6 +8,7 @@ import (
 
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestDecodeBlock(t *testing.T) {
@@ -29,63 +30,24 @@ func TestDecodeBlock(t *testing.T) {
 	if err := block.DecodeBinary(bytes.NewReader(rawBlockBytes)); err != nil {
 		t.Fatal(err)
 	}
-	if block.Index != uint32(rawBlockIndex) {
+	assert.Equal(t, uint32(rawBlockIndex), block.Index)
-		t.Fatalf("expected the index to the block to be %d got %d", rawBlockIndex, block.Index)
+	assert.Equal(t, uint32(rawBlockTimestamp), block.Timestamp)
-	}
+	assert.Equal(t, uint64(rawBlockConsensusData), block.ConsensusData)
-	if block.Timestamp != uint32(rawBlockTimestamp) {
+	assert.Equal(t, rawBlockPrevHash, block.PrevHash.String())
-		t.Fatalf("expected timestamp to be %d got %d", rawBlockTimestamp, block.Timestamp)
+	assert.Equal(t, rawBlockHash, block.Hash().String())
-	}
-	if block.ConsensusData != uint64(rawBlockConsensusData) {
-		t.Fatalf("expected consensus data to be %d got %d", rawBlockConsensusData, block.ConsensusData)
-	}
-	if block.PrevHash.String() != rawBlockPrevHash {
-		t.Fatalf("expected prev block hash to be %s got %s", rawBlockPrevHash, block.PrevHash)
-	}
-	hash, err := block.Hash()
-	if err != nil {
-		t.Fatal(err)
-	}
-	if hash.String() != rawBlockHash {
-		t.Fatalf("expected hash of the block to be %s got %s", rawBlockHash, hash)
-	}
-}
-
-func newBlockBase() BlockBase {
-	return BlockBase{
-		Version:       0,
-		PrevHash:      sha256.Sum256([]byte("a")),
-		MerkleRoot:    sha256.Sum256([]byte("b")),
-		Timestamp:     999,
-		Index:         1,
-		ConsensusData: 1111,
-		NextConsensus: util.Uint160{},
-		Script: &transaction.Witness{
-			VerificationScript: []byte{0x0},
-			InvocationScript:   []byte{0x1},
-		},
-	}
 }
 
 func TestHashBlockEqualsHashHeader(t *testing.T) {
-	base := newBlockBase()
+	block := newBlock(0)
-	b := &Block{BlockBase: base}
+	assert.Equal(t, block.Hash(), block.Header().Hash())
-	head := &Header{BlockBase: base}
-
-	bhash, _ := b.Hash()
-	headhash, _ := head.Hash()
-	if bhash != headhash {
-		t.Fatalf("expected both hashes to be equal %s and %s", bhash, headhash)
-	}
 }
 
 func TestBlockVerify(t *testing.T) {
-	block := &Block{
+	block := newBlock(
-		BlockBase: newBlockBase(),
+		0,
-		Transactions: []*transaction.Transaction{
+		newTX(transaction.MinerType),
-			{Type: transaction.MinerType},
+		newTX(transaction.IssueType),
-			{Type: transaction.IssueType},
+	)
-		},
-	}
 
 	if !block.Verify(false) {
 		t.Fatal("block should be verified")
@@ -109,3 +71,19 @@ func TestBlockVerify(t *testing.T) {
 		t.Fatal("block should not by verified")
 	}
 }
+
+func newBlockBase() BlockBase {
+	return BlockBase{
+		Version:       0,
+		PrevHash:      sha256.Sum256([]byte("a")),
+		MerkleRoot:    sha256.Sum256([]byte("b")),
+		Timestamp:     999,
+		Index:         1,
+		ConsensusData: 1111,
+		NextConsensus: util.Uint160{},
+		Script: &transaction.Witness{
+			VerificationScript: []byte{0x0},
+			InvocationScript:   []byte{0x1},
+		},
+	}
+}

pkg/core/blockchain.go

@@ -3,17 +3,19 @@ package core
 import (
 	"bytes"
 	"encoding/binary"
-	"log"
+	"fmt"
-	"sync"
+	"os"
+	"sync/atomic"
 	"time"
 
 	"github.com/CityOfZion/neo-go/pkg/util"
+	log "github.com/go-kit/kit/log"
 )
 
 // tuning parameters
 const (
 	secondsPerBlock  = 15
-	writeHdrBatchCnt = 2000
+	headerBatchCount = 2000
 )
 
 var (
@@ -22,188 +24,217 @@ var (
 
 // Blockchain holds the chain.
 type Blockchain struct {
-	logger *log.Logger
+	logger log.Logger
 
 	// Any object that satisfies the BlockchainStorer interface.
 	Store
 
-	// current index of the heighest block
+	// Current index/height of the highest block.
-	currentBlockHeight uint32
+	// Read access should always be called by BlockHeight().
+	// Writes access should only happen in persist().
+	blockHeight uint32
 
-	// number of headers stored
+	// Number of headers stored.
 	storedHeaderCount uint32
 
-	mtx sync.RWMutex
+	blockCache *Cache
 
-	// index of headers hashes
+	startHash util.Uint256
-	headerIndex []util.Uint256
+
+	// Only for operating on the headerList.
+	headersOp     chan headersOpFunc
+	headersOpDone chan struct{}
 }
 
-// NewBlockchain returns a pointer to a Blockchain.
+type headersOpFunc func(headerList *HeaderHashList)
-func NewBlockchain(s Store, l *log.Logger, startHash util.Uint256) *Blockchain {
+
+// NewBlockchain creates a new Blockchain object.
+func NewBlockchain(s Store, startHash util.Uint256) *Blockchain {
+	logger := log.NewLogfmtLogger(os.Stderr)
+	logger = log.With(logger, "component", "blockchain")
+
 	bc := &Blockchain{
-		logger: l,
+		logger:        logger,
 		Store:         s,
+		headersOp:     make(chan headersOpFunc),
+		headersOpDone: make(chan struct{}),
+		startHash:     startHash,
+		blockCache:    NewCache(),
 	}
-
+	go bc.run()
-	// Starthash is 0, so we will create the genesis block.
+	bc.init()
-	if startHash.Equals(util.Uint256{}) {
-		bc.logger.Fatal("genesis block not yet implemented")
-	}
-
-	bc.headerIndex = []util.Uint256{startHash}
 
 	return bc
 }
 
-// genesisBlock creates the genesis block for the chain.
+func (bc *Blockchain) init() {
-// hash of the genesis block:
+	// for the initial header, for now
-// d42561e3d30e15be6400b6df2f328e02d2bf6354c41dce433bc57687c82144bf
+	bc.storedHeaderCount = 1
-func (bc *Blockchain) genesisBlock() *Block {
+}
-	timestamp := uint32(time.Date(2016, 7, 15, 15, 8, 21, 0, time.UTC).Unix())
 
-	// TODO: for testing I will hardcode the merkleroot.
+func (bc *Blockchain) run() {
-	// This let's me focus on the bringing all the puzzle pieces
+	headerList := NewHeaderHashList(bc.startHash)
-	// togheter much faster.
+	for {
-	// For more information about the genesis block:
+		select {
-	// https://neotracker.io/block/height/0
+		case op := <-bc.headersOp:
-	mr, _ := util.Uint256DecodeString("803ff4abe3ea6533bcc0be574efa02f83ae8fdc651c879056b0d9be336c01bf4")
+			op(headerList)
-
+			bc.headersOpDone <- struct{}{}
-	return &Block{
+		}
-		BlockBase: BlockBase{
-			Version:       0,
-			PrevHash:      util.Uint256{},
-			MerkleRoot:    mr,
-			Timestamp:     timestamp,
-			Index:         0,
-			ConsensusData: 2083236893,     // nioctib ^^
-			NextConsensus: util.Uint160{}, // todo
-		},
 	}
 }
 
-// AddBlock (to be continued after headers is finished..)
 func (bc *Blockchain) AddBlock(block *Block) error {
-	// TODO: caching
+	if !bc.blockCache.Has(block.Hash()) {
-	headerLen := len(bc.headerIndex)
+		bc.blockCache.Add(block.Hash(), block)
+	}
 
+	headerLen := int(bc.HeaderHeight() + 1)
 	if int(block.Index-1) >= headerLen {
 		return nil
 	}
-
 	if int(block.Index) == headerLen {
 		// todo: if (VerifyBlocks && !block.Verify()) return false;
 	}
-
+	return bc.AddHeaders(block.Header())
-	if int(block.Index) < headerLen {
-		return nil
-	}
-
-	return nil
 }
 
-func (bc *Blockchain) addHeader(header *Header) error {
+func (bc *Blockchain) AddHeaders(headers ...*Header) (err error) {
-	return bc.AddHeaders(header)
+	var (
-}
+		start = time.Now()
+		batch = Batch{}
+	)
 
-// AddHeaders processes the given headers.
+	bc.headersOp <- func(headerList *HeaderHashList) {
-func (bc *Blockchain) AddHeaders(headers ...*Header) error {
-	start := time.Now()
-
-	bc.mtx.Lock()
-	defer bc.mtx.Unlock()
-
-	batch := Batch{}
 		for _, h := range headers {
-		if int(h.Index-1) >= len(bc.headerIndex) {
+			if int(h.Index-1) >= headerList.Len() {
-			bc.logger.Printf("height of block higher then header index %d %d\n",
+				err = fmt.Errorf(
-				h.Index, len(bc.headerIndex))
+					"height of block higher then current header height %d > %d\n",
-			break
+					h.Index, headerList.Len(),
+				)
+				return
 			}
-		if int(h.Index) < len(bc.headerIndex) {
+			if int(h.Index) < headerList.Len() {
 				continue
 			}
 			if !h.Verify() {
-			bc.logger.Printf("header %v is invalid", h)
+				err = fmt.Errorf("header %v is invalid", h)
-			break
+				return
 			}
-		if err := bc.processHeader(h, batch); err != nil {
+			if err = bc.processHeader(h, batch, headerList); err != nil {
-			return err
+				return
 			}
 		}
 
 		// TODO: Implement caching strategy.
 		if len(batch) > 0 {
-		// Write all batches.
+			if err = bc.writeBatch(batch); err != nil {
-		if err := bc.writeBatch(batch); err != nil {
+				return
+			}
+			bc.logger.Log(
+				"msg", "done processing headers",
+				"index", headerList.Len()-1,
+				"took", time.Since(start).Seconds(),
+			)
+		}
+	}
+	<-bc.headersOpDone
 	return err
-		}
-
-		bc.logger.Printf("done processing headers up to index %d took %f Seconds",
-			bc.HeaderHeight(), time.Since(start).Seconds())
-	}
-
-	return nil
 }
 
-// processHeader processes 1 header.
+// processHeader processes the given header. Note that this is only thread safe
-func (bc *Blockchain) processHeader(h *Header, batch Batch) error {
+// if executed in headers operation.
-	hash, err := h.Hash()
+func (bc *Blockchain) processHeader(h *Header, batch Batch, headerList *HeaderHashList) error {
-	if err != nil {
+	headerList.Add(h.Hash())
-		return err
-	}
-	bc.headerIndex = append(bc.headerIndex, hash)
-
-	for int(h.Index)-writeHdrBatchCnt >= int(bc.storedHeaderCount) {
-		// hdrsToWrite = bc.headerIndex[bc.storedHeaderCount : bc.storedHeaderCount+writeHdrBatchCnt]
-
-		// NOTE: from original #c to be implemented:
-		//
-		// w.Write(header_index.Skip((int)stored_header_count).Take(2000).ToArray());
-		// w.Flush();
-		// batch.Put(SliceBuilder.Begin(DataEntryPrefix.IX_HeaderHashList).Add(stored_header_count), ms.ToArray());
-
-		bc.storedHeaderCount += writeHdrBatchCnt
-	}
 
 	buf := new(bytes.Buffer)
+	for int(h.Index)-headerBatchCount >= int(bc.storedHeaderCount) {
+		if err := headerList.Write(buf, int(bc.storedHeaderCount), headerBatchCount); err != nil {
+			return err
+		}
+		key := makeEntryPrefixInt(preIXHeaderHashList, int(bc.storedHeaderCount))
+		batch[&key] = buf.Bytes()
+		bc.storedHeaderCount += headerBatchCount
+		buf.Reset()
+	}
+
+	buf.Reset()
 	if err := h.EncodeBinary(buf); err != nil {
 		return err
 	}
 
-	preBlock := preDataBlock.add(hash.BytesReverse())
+	key := makeEntryPrefix(preDataBlock, h.Hash().BytesReverse())
-	batch[&preBlock] = buf.Bytes()
+	batch[&key] = buf.Bytes()
-	preHeader := preSYSCurrentHeader.toSlice()
+	key = preSYSCurrentHeader.bytes()
-	batch[&preHeader] = hashAndIndexToBytes(hash, h.Index)
+	batch[&key] = hashAndIndexToBytes(h.Hash(), h.Index)
 
 	return nil
 }
 
-// CurrentBlockHash return the lastest hash in the header index.
+func (bc *Blockchain) persistBlock(block *Block) error {
-func (bc *Blockchain) CurrentBlockHash() (hash util.Uint256) {
+	bc.blockHeight = block.Index
-	if len(bc.headerIndex) == 0 {
+	return nil
-		return
+}
-	}
-	if len(bc.headerIndex) < int(bc.currentBlockHeight) {
-		return
-	}
 
-	return bc.headerIndex[bc.currentBlockHeight]
+func (bc *Blockchain) persist() (err error) {
+	var (
+		persisted = 0
+		lenCache  = bc.blockCache.Len()
+	)
+
+	for lenCache > persisted {
+		if bc.HeaderHeight()+1 <= bc.BlockHeight() {
+			break
+		}
+		bc.headersOp <- func(headerList *HeaderHashList) {
+			hash := headerList.Get(int(bc.BlockHeight() + 1))
+			if block, ok := bc.blockCache.GetBlock(hash); ok {
+				if err = bc.persistBlock(block); err != nil {
+					return
+				}
+				bc.blockCache.Delete(hash)
+				persisted++
+			} else {
+				bc.logger.Log(
+					"msg", "block not found in cache",
+					"hash", block.Hash(),
+				)
+			}
+		}
+		<-bc.headersOpDone
+	}
+	return
+}
+
+// CurrentBlockHash returns the heighest processed block hash.
+func (bc *Blockchain) CurrentBlockHash() (hash util.Uint256) {
+	bc.headersOp <- func(headerList *HeaderHashList) {
+		hash = headerList.Get(int(bc.BlockHeight()))
+	}
+	<-bc.headersOpDone
+	return
 }
 
 // CurrentHeaderHash returns the hash of the latest known header.
 func (bc *Blockchain) CurrentHeaderHash() (hash util.Uint256) {
-	return bc.headerIndex[len(bc.headerIndex)-1]
+	bc.headersOp <- func(headerList *HeaderHashList) {
+		hash = headerList.Last()
+	}
+	<-bc.headersOpDone
+	return
 }
 
-// BlockHeight return the height/index of the latest block this node has.
+// BlockHeight returns the height/index of the highest block.
 func (bc *Blockchain) BlockHeight() uint32 {
-	return bc.currentBlockHeight
+	return atomic.LoadUint32(&bc.blockHeight)
 }
 
-// HeaderHeight returns the current index of the headers.
+// HeaderHeight returns the index/height of the highest header.
-func (bc *Blockchain) HeaderHeight() uint32 {
+func (bc *Blockchain) HeaderHeight() (n uint32) {
-	return uint32(len(bc.headerIndex)) - 1
+	bc.headersOp <- func(headerList *HeaderHashList) {
+		n = uint32(headerList.Len() - 1)
+	}
+	<-bc.headersOpDone
+	return
 }
 
 func hashAndIndexToBytes(h util.Uint256, index uint32) []byte {

pkg/core/blockchain_test.go

@@ -1,48 +1,70 @@
 package core
 
 import (
-	"log"
-	"os"
 	"testing"
 
-	"github.com/CityOfZion/neo-go/pkg/core/transaction"
 	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestNewBlockchain(t *testing.T) {
 	startHash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
-	bc := NewBlockchain(nil, nil, startHash)
+	bc := NewBlockchain(nil, startHash)
 
-	want := uint32(0)
+	assert.Equal(t, uint32(0), bc.BlockHeight())
-	if have := bc.BlockHeight(); want != have {
+	assert.Equal(t, uint32(0), bc.HeaderHeight())
-		t.Fatalf("expected %d got %d", want, have)
+	assert.Equal(t, uint32(1), bc.storedHeaderCount)
-	}
+	assert.Equal(t, startHash, bc.startHash)
-	if have := bc.HeaderHeight(); want != have {
-		t.Fatalf("expected %d got %d", want, have)
-	}
-	if have := bc.storedHeaderCount; want != have {
-		t.Fatalf("expected %d got %d", want, have)
-	}
-	if !bc.CurrentBlockHash().Equals(startHash) {
-		t.Fatalf("expected current block hash to be %d got %s", startHash, bc.CurrentBlockHash())
-	}
 }
 
 func TestAddHeaders(t *testing.T) {
-	startHash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
+	bc := newTestBC()
-	bc := NewBlockchain(NewMemoryStore(), log.New(os.Stdout, "", 0), startHash)
+	h1 := newBlock(1).Header()
-
+	h2 := newBlock(2).Header()
-	h1 := &Header{BlockBase: BlockBase{Version: 0, Index: 1, Script: &transaction.Witness{}}}
+	h3 := newBlock(3).Header()
-	h2 := &Header{BlockBase: BlockBase{Version: 0, Index: 2, Script: &transaction.Witness{}}}
-	h3 := &Header{BlockBase: BlockBase{Version: 0, Index: 3, Script: &transaction.Witness{}}}
 
 	if err := bc.AddHeaders(h1, h2, h3); err != nil {
 		t.Fatal(err)
 	}
-	if want, have := h3.Index, bc.HeaderHeight(); want != have {
+
-		t.Fatalf("expected header height of %d got %d", want, have)
+	assert.Equal(t, 0, bc.blockCache.Len())
-	}
+	assert.Equal(t, h3.Index, bc.HeaderHeight())
-	if want, have := uint32(0), bc.storedHeaderCount; want != have {
+	assert.Equal(t, uint32(1), bc.storedHeaderCount)
-		t.Fatalf("expected stored header count to be %d got %d", want, have)
+	assert.Equal(t, uint32(0), bc.BlockHeight())
-	}
+	assert.Equal(t, h3.Hash(), bc.CurrentHeaderHash())
+}
+
+func TestAddBlock(t *testing.T) {
+	bc := newTestBC()
+	blocks := []*Block{
+		newBlock(1),
+		newBlock(2),
+		newBlock(3),
+	}
+
+	for i := 0; i < len(blocks); i++ {
+		if err := bc.AddBlock(blocks[i]); err != nil {
+			t.Fatal(err)
+		}
+	}
+
+	lastBlock := blocks[len(blocks)-1]
+	assert.Equal(t, 3, bc.blockCache.Len())
+	assert.Equal(t, lastBlock.Index, bc.HeaderHeight())
+	assert.Equal(t, lastBlock.Hash(), bc.CurrentHeaderHash())
+	assert.Equal(t, uint32(1), bc.storedHeaderCount)
+
+	if err := bc.persist(); err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, lastBlock.Index, bc.BlockHeight())
+	assert.Equal(t, lastBlock.Hash(), bc.CurrentHeaderHash())
+	assert.Equal(t, 0, bc.blockCache.Len())
+}
+
+func newTestBC() *Blockchain {
+	startHash, _ := util.Uint256DecodeString("a")
+	bc := NewBlockchain(NewMemoryStore(), startHash)
+	return bc
 }

pkg/core/cache.go

@@ -0,0 +1,73 @@
+package core
+
+import (
+	"sync"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// Cache is data structure with fixed type key of Uint256, but has a
+// generic value. Used for block and header cash types.
+type Cache struct {
+	lock sync.RWMutex
+	m    map[util.Uint256]interface{}
+}
+
+// NewCache returns a ready to use Cache object.
+func NewCache() *Cache {
+	return &Cache{
+		m: make(map[util.Uint256]interface{}),
+	}
+}
+
+// GetBlock will return a Block type from the cache.
+func (c *Cache) GetBlock(h util.Uint256) (block *Block, ok bool) {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	return c.getBlock(h)
+}
+
+func (c *Cache) getBlock(h util.Uint256) (block *Block, ok bool) {
+	if v, b := c.m[h]; b {
+		block, ok = v.(*Block)
+		return
+	}
+	return
+}
+
+// Add adds the given hash along with its value to the cache.
+func (c *Cache) Add(h util.Uint256, v interface{}) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	c.add(h, v)
+}
+
+func (c *Cache) add(h util.Uint256, v interface{}) {
+	c.m[h] = v
+}
+
+func (c *Cache) has(h util.Uint256) bool {
+	_, ok := c.m[h]
+	return ok
+}
+
+// Hash returns whether the cach contains the given hash.
+func (c *Cache) Has(h util.Uint256) bool {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	return c.has(h)
+}
+
+// Len return the number of items present in the cache.
+func (c *Cache) Len() int {
+	c.lock.RLock()
+	defer c.lock.RUnlock()
+	return len(c.m)
+}
+
+// Delete removes the item out of the cache.
+func (c *Cache) Delete(h util.Uint256) {
+	c.lock.Lock()
+	defer c.lock.Unlock()
+	delete(c.m, h)
+}

pkg/core/header_hash_list.go

@@ -0,0 +1,66 @@
+package core
+
+import (
+	"encoding/binary"
+	"io"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// A HeaderHashList represents a list of header hashes.
+type HeaderHashList struct {
+	hashes []util.Uint256
+}
+
+// NewHeaderHashList return a new pointer to a HeaderHashList.
+func NewHeaderHashList(hashes ...util.Uint256) *HeaderHashList {
+	return &HeaderHashList{
+		hashes: hashes,
+	}
+}
+
+// Add appends the given hash to the list of hashes.
+func (l *HeaderHashList) Add(h util.Uint256) {
+	l.hashes = append(l.hashes, h)
+}
+
+// Len return the length of the underlying hashes slice.
+func (l *HeaderHashList) Len() int {
+	return len(l.hashes)
+}
+
+// Get returns the hash by the given index.
+func (l *HeaderHashList) Get(i int) util.Uint256 {
+	if l.Len() < i {
+		return util.Uint256{}
+	}
+	return l.hashes[i]
+}
+
+// Last return the last hash in the HeaderHashList.
+func (l *HeaderHashList) Last() util.Uint256 {
+	return l.hashes[l.Len()-1]
+}
+
+// Slice return a subslice of the underlying hashes.
+// Subsliced from start to end.
+// Example:
+// headers := headerList.Slice(0, 2000)
+func (l *HeaderHashList) Slice(start, end int) []util.Uint256 {
+	return l.hashes[start:end]
+}
+
+// WriteTo will write n underlying hashes to the given io.Writer
+// starting from start.
+func (l *HeaderHashList) Write(w io.Writer, start, n int) error {
+	if err := util.WriteVarUint(w, uint64(n)); err != nil {
+		return err
+	}
+	hashes := l.Slice(start, start+n)
+	for _, hash := range hashes {
+		if err := binary.Write(w, binary.LittleEndian, hash); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/core/helper_test.go

@@ -0,0 +1,40 @@
+package core
+
+import (
+	"crypto/sha256"
+	"time"
+
+	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+func newBlock(index uint32, txs ...*transaction.Transaction) *Block {
+	b := &Block{
+		BlockBase: BlockBase{
+			Version:       0,
+			PrevHash:      sha256.Sum256([]byte("a")),
+			MerkleRoot:    sha256.Sum256([]byte("b")),
+			Timestamp:     uint32(time.Now().UTC().Unix()),
+			Index:         index,
+			ConsensusData: 1111,
+			NextConsensus: util.Uint160{},
+			Script: &transaction.Witness{
+				VerificationScript: []byte{0x0},
+				InvocationScript:   []byte{0x1},
+			},
+		},
+		Transactions: txs,
+	}
+	hash, err := b.createHash()
+	if err != nil {
+		panic(err)
+	}
+	b.hash = hash
+	return b
+}
+
+func newTX(t transaction.TXType) *transaction.Transaction {
+	return &transaction.Transaction{
+		Type: t,
+	}
+}

pkg/core/leveldb_store.go

@@ -21,6 +21,5 @@ func (s *LevelDBStore) writeBatch(batch Batch) error {
 	for k, v := range batch {
 		b.Put(*k, v)
 	}
-
 	return s.db.Write(b, nil)
 }

pkg/core/memory_store.go

@@ -1,6 +1,7 @@
 package core
 
-// MemoryStore is an in memory implementation of a BlockChainStorer.
+// MemoryStore is an in memory implementation of a BlockChainStorer
+// that should only be used for testing.
 type MemoryStore struct {
 }
 
@@ -14,5 +15,10 @@ func (m *MemoryStore) write(key, value []byte) error {
 }
 
 func (m *MemoryStore) writeBatch(batch Batch) error {
+	for k, v := range batch {
+		if err := m.write(*k, v); err != nil {
+			return err
+		}
+	}
 	return nil
 }

pkg/core/store.go

@@ -1,17 +1,13 @@
 package core
 
+import (
+	"bytes"
+	"encoding/binary"
+)
+
 type dataEntry uint8
 
-func (e dataEntry) add(b []byte) []byte {
+func (e dataEntry) bytes() []byte {
-	dest := make([]byte, len(b)+1)
-	dest[0] = byte(e)
-	for i := 1; i < len(b); i++ {
-		dest[i] = b[i]
-	}
-	return dest
-}
-
-func (e dataEntry) toSlice() []byte {
 	return []byte{byte(e)}
 }
 
@@ -32,6 +28,21 @@ const (
 	preSYSVersion        dataEntry = 0xf0
 )
 
+func makeEntryPrefixInt(e dataEntry, n int) []byte {
+	buf := new(bytes.Buffer)
+	binary.Write(buf, binary.LittleEndian, n)
+	return makeEntryPrefix(e, buf.Bytes())
+}
+
+func makeEntryPrefix(e dataEntry, b []byte) []byte {
+	dest := make([]byte, len(b)+1)
+	dest[0] = byte(e)
+	for i := 1; i < len(b); i++ {
+		dest[i] = b[i]
+	}
+	return dest
+}
+
 // Store is anything that can persist and retrieve the blockchain.
 type Store interface {
 	write(k, v []byte) error
@@ -39,5 +50,5 @@ type Store interface {
 }
 
 // Batch is a data type used to store data for later batch operations
-// by any Store.
+// that can be used by any Store interface implementation.
 type Batch map[*[]byte][]byte

pkg/core/transaction/transaction.go

@@ -10,7 +10,7 @@ import (
 // Transaction is a process recorded in the NEO blockchain.
 type Transaction struct {
 	// The type of the transaction.
-	Type TransactionType
+	Type TXType
 
 	// The trading version which is currently 0.
 	Version uint8

pkg/core/transaction/type.go

@@ -1,26 +1,26 @@
 package transaction
 
-// TransactionType is the type of a transaction.
+// TXType is the type of a transaction.
-type TransactionType uint8
+type TXType uint8
 
 // All processes in NEO system are recorded in transactions.
 // There are several types of transactions.
 const (
-	MinerType      TransactionType = 0x00
+	MinerType      TXType = 0x00
-	IssueType      TransactionType = 0x01
+	IssueType      TXType = 0x01
-	ClaimType      TransactionType = 0x02
+	ClaimType      TXType = 0x02
-	EnrollmentType TransactionType = 0x20
+	EnrollmentType TXType = 0x20
-	VotingType     TransactionType = 0x24
+	VotingType     TXType = 0x24
-	RegisterType   TransactionType = 0x40
+	RegisterType   TXType = 0x40
-	ContractType   TransactionType = 0x80
+	ContractType   TXType = 0x80
-	StateType      TransactionType = 0x90
+	StateType      TXType = 0x90
-	AgencyType     TransactionType = 0xb0
+	AgencyType     TXType = 0xb0
-	PublishType    TransactionType = 0xd0
+	PublishType    TXType = 0xd0
-	InvocationType TransactionType = 0xd1
+	InvocationType TXType = 0xd1
 )
 
 // String implements the stringer interface.
-func (t TransactionType) String() string {
+func (t TXType) String() string {
 	switch t {
 	case MinerType:
 		return "miner transaction"

pkg/core/util.go

@@ -0,0 +1,12 @@
+package core
+
+import "github.com/CityOfZion/neo-go/pkg/util"
+
+// Utilities for quick bootstrapping blockchains. Normally we should
+// create the genisis block. For now (to speed up development) we will add
+// The hashes manually.
+
+func GenesisHashPrivNet() util.Uint256 {
+	hash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
+	return hash
+}

pkg/crypto/base58.go

@@ -79,6 +79,7 @@ func Base58Encode(bytes []byte) string {
 	return encoded
 }
 
+// Base58CheckDecode decodes the given string.
 func Base58CheckDecode(s string) (b []byte, err error) {
 	b, err = Base58Decode(s)
 	if err != nil {

pkg/network/message.go

@@ -61,26 +61,28 @@ type Message struct {
 	Payload payload.Payload
 }
 
-type commandType string
+// CommandType represents the type of a message command.
+type CommandType string
 
 // valid commands used to send between nodes.
 const (
-	cmdVersion    commandType = "version"
+	CMDVersion    CommandType = "version"
-	cmdVerack                 = "verack"
+	CMDVerack     CommandType = "verack"
-	cmdGetAddr                = "getaddr"
+	CMDGetAddr    CommandType = "getaddr"
-	cmdAddr                   = "addr"
+	CMDAddr       CommandType = "addr"
-	cmdGetHeaders             = "getheaders"
+	CMDGetHeaders CommandType = "getheaders"
-	cmdHeaders                = "headers"
+	CMDHeaders    CommandType = "headers"
-	cmdGetBlocks              = "getblocks"
+	CMDGetBlocks  CommandType = "getblocks"
-	cmdInv                    = "inv"
+	CMDInv        CommandType = "inv"
-	cmdGetData                = "getdata"
+	CMDGetData    CommandType = "getdata"
-	cmdBlock                  = "block"
+	CMDBlock      CommandType = "block"
-	cmdTX                     = "tx"
+	CMDTX         CommandType = "tx"
-	cmdConsensus              = "consensus"
+	CMDConsensus  CommandType = "consensus"
-	cmdUnknown                = "unknown"
+	CMDUnknown    CommandType = "unknown"
 )
 
-func newMessage(magic NetMode, cmd commandType, p payload.Payload) *Message {
+// NewMessage returns a new message with the given payload.
+func NewMessage(magic NetMode, cmd CommandType, p payload.Payload) *Message {
 	var (
 		size     uint32
 		checksum []byte
@@ -106,36 +108,36 @@ func newMessage(magic NetMode, cmd commandType, p payload.Payload) *Message {
 	}
 }
 
-// Converts the 12 byte command slice to a commandType.
+// CommandType converts the 12 byte command slice to a CommandType.
-func (m *Message) commandType() commandType {
+func (m *Message) CommandType() CommandType {
 	cmd := cmdByteArrayToString(m.Command)
 	switch cmd {
 	case "version":
-		return cmdVersion
+		return CMDVersion
 	case "verack":
-		return cmdVerack
+		return CMDVerack
 	case "getaddr":
-		return cmdGetAddr
+		return CMDGetAddr
 	case "addr":
-		return cmdAddr
+		return CMDAddr
 	case "getheaders":
-		return cmdGetHeaders
+		return CMDGetHeaders
 	case "headers":
-		return cmdHeaders
+		return CMDHeaders
 	case "getblocks":
-		return cmdGetBlocks
+		return CMDGetBlocks
 	case "inv":
-		return cmdInv
+		return CMDInv
 	case "getdata":
-		return cmdGetData
+		return CMDGetData
 	case "block":
-		return cmdBlock
+		return CMDBlock
 	case "tx":
-		return cmdTX
+		return CMDTX
 	case "consensus":
-		return cmdConsensus
+		return CMDConsensus
 	default:
-		return cmdUnknown
+		return CMDUnknown
 	}
 }
 
@@ -185,36 +187,35 @@ func (m *Message) decodePayload(r io.Reader) error {
 		return errChecksumMismatch
 	}
 
-	//r = bytes.NewReader(buf)
 	r = buf
 	var p payload.Payload
-	switch m.commandType() {
+	switch m.CommandType() {
-	case cmdVersion:
+	case CMDVersion:
 		p = &payload.Version{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
 		}
-	case cmdInv:
+	case CMDInv:
 		p = &payload.Inventory{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
 		}
-	case cmdAddr:
+	case CMDAddr:
 		p = &payload.AddressList{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
 		}
-	case cmdBlock:
+	case CMDBlock:
 		p = &core.Block{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
 		}
-	case cmdGetHeaders:
+	case CMDGetHeaders:
 		p = &payload.GetBlocks{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
 		}
-	case cmdHeaders:
+	case CMDHeaders:
 		p = &payload.Headers{}
 		if err := p.DecodeBinary(r); err != nil {
 			return err
@@ -242,7 +243,7 @@ func (m *Message) encode(w io.Writer) error {
 
 // convert a command (string) to a byte slice filled with 0 bytes till
 // size 12.
-func cmdToByteArray(cmd commandType) [cmdSize]byte {
+func cmdToByteArray(cmd CommandType) [cmdSize]byte {
 	cmdLen := len(cmd)
 	if cmdLen > cmdSize {
 		panic("exceeded command max length of size 12")

pkg/network/message_test.go

@@ -2,39 +2,33 @@ package network
 
 import (
 	"bytes"
-	"reflect"
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/network/payload"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestMessageEncodeDecode(t *testing.T) {
-	m := newMessage(ModeTestNet, cmdVersion, nil)
+	m := NewMessage(ModeTestNet, CMDVersion, nil)
 
 	buf := &bytes.Buffer{}
 	if err := m.encode(buf); err != nil {
 		t.Error(err)
 	}
-
+	assert.Equal(t, len(buf.Bytes()), minMessageSize)
-	if n := len(buf.Bytes()); n < minMessageSize {
-		t.Fatalf("message should be at least %d bytes got %d", minMessageSize, n)
-	}
-	if n := len(buf.Bytes()); n > minMessageSize {
-		t.Fatalf("message without a payload should be exact %d bytes got %d", minMessageSize, n)
-	}
 
 	md := &Message{}
 	if err := md.decode(buf); err != nil {
 		t.Error(err)
 	}
-	if !reflect.DeepEqual(m, md) {
+	assert.Equal(t, m, md)
-		t.Errorf("both messages should be equal: %v != %v", m, md)
-	}
 }
 
 func TestMessageEncodeDecodeWithVersion(t *testing.T) {
-	p := payload.NewVersion(12227, 2000, "/neo:2.6.0/", 0, true)
+	var (
-	m := newMessage(ModeTestNet, cmdVersion, p)
+		p = payload.NewVersion(12227, 2000, "/neo:2.6.0/", 0, true)
+		m = NewMessage(ModeTestNet, CMDVersion, p)
+	)
 
 	buf := new(bytes.Buffer)
 	if err := m.encode(buf); err != nil {
@@ -45,15 +39,14 @@ func TestMessageEncodeDecodeWithVersion(t *testing.T) {
 	if err := mDecode.decode(buf); err != nil {
 		t.Fatal(err)
 	}
-
+	assert.Equal(t, m, mDecode)
-	if !reflect.DeepEqual(m, mDecode) {
-		t.Fatalf("expected both messages to be equal %v and %v", m, mDecode)
-	}
 }
 
 func TestMessageInvalidChecksum(t *testing.T) {
-	p := payload.NewVersion(1111, 3000, "/NEO:2.6.0/", 0, true)
+	var (
-	m := newMessage(ModeTestNet, cmdVersion, p)
+		p = payload.NewVersion(1111, 3000, "/NEO:2.6.0/", 0, true)
+		m = NewMessage(ModeTestNet, CMDVersion, p)
+	)
 	m.Checksum = 1337
 
 	buf := new(bytes.Buffer)

pkg/network/node.go

@@ -0,0 +1,219 @@
+package network
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/network/payload"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	log "github.com/go-kit/kit/log"
+)
+
+const (
+	protoVersion = 0
+)
+
+var protoTickInterval = 5 * time.Second
+
+// Node represents the local node.
+type Node struct {
+	// Config fields may not be modified while the server is running.
+	Config
+
+	logger   log.Logger
+	server   *Server
+	services uint64
+	bc       *core.Blockchain
+	protoIn  chan messageTuple
+}
+
+// messageTuple respresents a tuple that holds the message being
+// send along with its peer.
+type messageTuple struct {
+	peer Peer
+	msg  *Message
+}
+
+func newNode(s *Server, cfg Config) *Node {
+	var startHash util.Uint256
+	if cfg.Net == ModePrivNet {
+		startHash = core.GenesisHashPrivNet()
+	}
+
+	bc := core.NewBlockchain(
+		core.NewMemoryStore(),
+		startHash,
+	)
+
+	logger := log.NewLogfmtLogger(os.Stderr)
+	logger = log.With(logger, "component", "node")
+
+	n := &Node{
+		Config:  cfg,
+		protoIn: make(chan messageTuple),
+		server:  s,
+		bc:      bc,
+		logger:  logger,
+	}
+	go n.handleMessages()
+
+	return n
+}
+
+func (n *Node) version() *payload.Version {
+	return payload.NewVersion(n.server.id, n.ListenTCP, n.UserAgent, 1, n.Relay)
+}
+
+func (n *Node) startProtocol(peer Peer) {
+	ticker := time.NewTicker(protoTickInterval).C
+
+	for {
+		select {
+		case <-ticker:
+			// Try to sync with the peer if his block height is higher then ours.
+			if peer.Version().StartHeight > n.bc.HeaderHeight() {
+				n.askMoreHeaders(peer)
+			}
+			// Only ask for more peers if the server has the capacity for it.
+			if n.server.hasCapacity() {
+				msg := NewMessage(n.Net, CMDGetAddr, nil)
+				peer.Send(msg)
+			}
+		case <-peer.Done():
+			return
+		}
+	}
+}
+
+// When a peer sends out his version we reply with verack after validating
+// the version.
+func (n *Node) handleVersionCmd(version *payload.Version, peer Peer) error {
+	msg := NewMessage(n.Net, CMDVerack, nil)
+	peer.Send(msg)
+	return nil
+}
+
+// handleInvCmd handles the forwarded inventory received from the peer.
+// We will use the getdata message to get more details about the received
+// inventory.
+// note: if the server has Relay on false, inventory messages are not received.
+func (n *Node) handleInvCmd(inv *payload.Inventory, peer Peer) error {
+	if !inv.Type.Valid() {
+		return fmt.Errorf("invalid inventory type received: %s", inv.Type)
+	}
+	if len(inv.Hashes) == 0 {
+		return errors.New("inventory has no hashes")
+	}
+	payload := payload.NewInventory(inv.Type, inv.Hashes)
+	peer.Send(NewMessage(n.Net, CMDGetData, payload))
+	return nil
+}
+
+// handleBlockCmd processes the received block received from its peer.
+func (n *Node) handleBlockCmd(block *core.Block, peer Peer) error {
+	n.logger.Log(
+		"event", "block received",
+		"index", block.Index,
+		"hash", block.Hash(),
+		"tx", len(block.Transactions),
+	)
+
+	return n.bc.AddBlock(block)
+}
+
+// After a node sends out the getaddr message its receives a list of known peers
+// in the network. handleAddrCmd processes that payload.
+func (n *Node) handleAddrCmd(addressList *payload.AddressList, peer Peer) error {
+	addrs := make([]string, len(addressList.Addrs))
+	for i := 0; i < len(addrs); i++ {
+		addrs[i] = addressList.Addrs[i].Address.String()
+	}
+	n.server.connectToPeers(addrs...)
+	return nil
+}
+
+// The handleHeadersCmd will process the received headers from its peer.
+// We call this in a routine cause we may block Peers Send() for to long.
+func (n *Node) handleHeadersCmd(headers *payload.Headers, peer Peer) error {
+	go func(headers []*core.Header) {
+		if err := n.bc.AddHeaders(headers...); err != nil {
+			n.logger.Log("msg", "failed processing headers", "err", err)
+			return
+		}
+		// The peer will respond with a maximum of 2000 headers in one batch.
+		// We will ask one more batch here if needed. Eventually we will get synced
+		// due to the startProtocol routine that will ask headers every protoTick.
+		if n.bc.HeaderHeight() < peer.Version().StartHeight {
+			n.askMoreHeaders(peer)
+		}
+	}(headers.Hdrs)
+
+	return nil
+}
+
+// askMoreHeaders will send a getheaders message to the peer.
+func (n *Node) askMoreHeaders(p Peer) {
+	start := []util.Uint256{n.bc.CurrentHeaderHash()}
+	payload := payload.NewGetBlocks(start, util.Uint256{})
+	p.Send(NewMessage(n.Net, CMDGetHeaders, payload))
+}
+
+// blockhain implements the Noder interface.
+func (n *Node) blockchain() *core.Blockchain { return n.bc }
+
+// handleProto implements the protoHandler interface.
+func (n *Node) handleProto(msg *Message, p Peer) {
+	n.protoIn <- messageTuple{
+		msg:  msg,
+		peer: p,
+	}
+}
+
+func (n *Node) handleMessages() {
+	for {
+		t := <-n.protoIn
+
+		var (
+			msg = t.msg
+			p   = t.peer
+			err error
+		)
+
+		switch msg.CommandType() {
+		case CMDVersion:
+			version := msg.Payload.(*payload.Version)
+			err = n.handleVersionCmd(version, p)
+		case CMDAddr:
+			addressList := msg.Payload.(*payload.AddressList)
+			err = n.handleAddrCmd(addressList, p)
+		case CMDInv:
+			inventory := msg.Payload.(*payload.Inventory)
+			err = n.handleInvCmd(inventory, p)
+		case CMDBlock:
+			block := msg.Payload.(*core.Block)
+			err = n.handleBlockCmd(block, p)
+		case CMDHeaders:
+			headers := msg.Payload.(*payload.Headers)
+			err = n.handleHeadersCmd(headers, p)
+		case CMDVerack:
+			// Only start the protocol if we got the version and verack
+			// received.
+			if p.Version() != nil {
+				go n.startProtocol(p)
+			}
+		case CMDUnknown:
+			err = errors.New("received non-protocol messgae")
+		}
+
+		if err != nil {
+			n.logger.Log(
+				"msg", "failed processing message",
+				"command", msg.CommandType,
+				"err", err,
+			)
+		}
+	}
+}

pkg/network/node_test.go

@@ -0,0 +1,7 @@
+package network
+
+import "testing"
+
+func TestHandleVersion(t *testing.T) {
+
+}

pkg/network/payload/addr.go

@@ -1,90 +0,0 @@
-package payload
-
-import (
-	"encoding/binary"
-	"io"
-
-	"github.com/CityOfZion/neo-go/pkg/util"
-)
-
-// AddrWithTime payload
-type AddrWithTime struct {
-	// Timestamp the node connected to the network.
-	Timestamp uint32
-	Services  uint64
-	Addr      util.Endpoint
-}
-
-// NewAddrWithTime return a pointer to AddrWithTime.
-func NewAddrWithTime(addr util.Endpoint) *AddrWithTime {
-	return &AddrWithTime{
-		Timestamp: 1337,
-		Services:  1,
-		Addr:      addr,
-	}
-}
-
-// Size implements the payload interface.
-func (p *AddrWithTime) Size() uint32 {
-	return 30
-}
-
-// DecodeBinary implements the Payload interface.
-func (p *AddrWithTime) DecodeBinary(r io.Reader) error {
-	err := binary.Read(r, binary.LittleEndian, &p.Timestamp)
-	err = binary.Read(r, binary.LittleEndian, &p.Services)
-	err = binary.Read(r, binary.BigEndian, &p.Addr.IP)
-	err = binary.Read(r, binary.BigEndian, &p.Addr.Port)
-
-	return err
-}
-
-// EncodeBinary implements the Payload interface.
-func (p *AddrWithTime) EncodeBinary(w io.Writer) error {
-	err := binary.Write(w, binary.LittleEndian, p.Timestamp)
-	err = binary.Write(w, binary.LittleEndian, p.Services)
-	err = binary.Write(w, binary.BigEndian, p.Addr.IP)
-	err = binary.Write(w, binary.BigEndian, p.Addr.Port)
-
-	return err
-}
-
-// AddressList is a list with AddrWithTime.
-type AddressList struct {
-	Addrs []*AddrWithTime
-}
-
-// DecodeBinary implements the Payload interface.
-func (p *AddressList) DecodeBinary(r io.Reader) error {
-	listLen := util.ReadVarUint(r)
-
-	p.Addrs = make([]*AddrWithTime, listLen)
-	for i := 0; i < int(listLen); i++ {
-		addr := &AddrWithTime{}
-		if err := addr.DecodeBinary(r); err != nil {
-			return err
-		}
-		p.Addrs[i] = addr
-	}
-
-	return nil
-}
-
-// EncodeBinary implements the Payload interface.
-func (p *AddressList) EncodeBinary(w io.Writer) error {
-	// Write the length of the slice
-	util.WriteVarUint(w, uint64(len(p.Addrs)))
-
-	for _, addr := range p.Addrs {
-		if err := addr.EncodeBinary(w); err != nil {
-			return err
-		}
-	}
-
-	return nil
-}
-
-// Size implements the Payloader interface.
-func (p *AddressList) Size() uint32 {
-	return uint32(len(p.Addrs) * 30)
-}

pkg/network/payload/addr_test.go

@@ -1,55 +0,0 @@
-package payload
-
-import (
-	"bytes"
-	"fmt"
-	"reflect"
-	"testing"
-
-	"github.com/CityOfZion/neo-go/pkg/util"
-)
-
-func TestEncodeDecodeAddr(t *testing.T) {
-	e, err := util.EndpointFromString("127.0.0.1:2000")
-	if err != nil {
-		t.Fatal(err)
-	}
-
-	addr := NewAddrWithTime(e)
-	buf := new(bytes.Buffer)
-	if err := addr.EncodeBinary(buf); err != nil {
-		t.Fatal(err)
-	}
-
-	addrDecode := &AddrWithTime{}
-	if err := addrDecode.DecodeBinary(buf); err != nil {
-		t.Fatal(err)
-	}
-
-	if !reflect.DeepEqual(addr, addrDecode) {
-		t.Fatalf("expected both addr payloads to be equal: %v and %v", addr, addrDecode)
-	}
-}
-
-func TestEncodeDecodeAddressList(t *testing.T) {
-	var lenList uint8 = 4
-	addrList := &AddressList{make([]*AddrWithTime, lenList)}
-	for i := 0; i < int(lenList); i++ {
-		e, _ := util.EndpointFromString(fmt.Sprintf("127.0.0.1:200%d", i))
-		addrList.Addrs[i] = NewAddrWithTime(e)
-	}
-
-	buf := new(bytes.Buffer)
-	if err := addrList.EncodeBinary(buf); err != nil {
-		t.Fatal(err)
-	}
-
-	addrListDecode := &AddressList{}
-	if err := addrListDecode.DecodeBinary(buf); err != nil {
-		t.Fatal(err)
-	}
-
-	if !reflect.DeepEqual(addrList, addrListDecode) {
-		t.Fatalf("expected both address list payloads to be equal: %v and %v", addrList, addrListDecode)
-	}
-}

pkg/network/payload/address.go

@@ -0,0 +1,85 @@
+package payload
+
+import (
+	"encoding/binary"
+	"io"
+	"time"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+)
+
+// AddressAndTime payload.
+type AddressAndTime struct {
+	Timestamp uint32
+	Services  uint64
+	Address   util.Endpoint
+}
+
+// NewAddressAndTime creates a new AddressAndTime object.
+func NewAddressAndTime(e util.Endpoint, t time.Time) *AddressAndTime {
+	return &AddressAndTime{
+		Timestamp: uint32(t.UTC().Unix()),
+		Services:  1,
+		Address:   e,
+	}
+}
+
+// DecodeBinary implements the Payload interface.
+func (p *AddressAndTime) DecodeBinary(r io.Reader) error {
+	if err := binary.Read(r, binary.LittleEndian, &p.Timestamp); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &p.Services); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.BigEndian, &p.Address.IP); err != nil {
+		return err
+	}
+	return binary.Read(r, binary.BigEndian, &p.Address.Port)
+}
+
+// EncodeBinary implements the Payload interface.
+func (p *AddressAndTime) EncodeBinary(w io.Writer) error {
+	if err := binary.Write(w, binary.LittleEndian, p.Timestamp); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.Services); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.BigEndian, p.Address.IP); err != nil {
+		return err
+	}
+	return binary.Write(w, binary.BigEndian, p.Address.Port)
+}
+
+// AddressList is a list with AddrAndTime.
+type AddressList struct {
+	Addrs []*AddressAndTime
+}
+
+// DecodeBinary implements the Payload interface.
+func (p *AddressList) DecodeBinary(r io.Reader) error {
+	listLen := util.ReadVarUint(r)
+
+	p.Addrs = make([]*AddressAndTime, listLen)
+	for i := 0; i < int(listLen); i++ {
+		p.Addrs[i] = &AddressAndTime{}
+		if err := p.Addrs[i].DecodeBinary(r); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// EncodeBinary implements the Payload interface.
+func (p *AddressList) EncodeBinary(w io.Writer) error {
+	if err := util.WriteVarUint(w, uint64(len(p.Addrs))); err != nil {
+		return err
+	}
+	for _, addr := range p.Addrs {
+		if err := addr.EncodeBinary(w); err != nil {
+			return err
+		}
+	}
+	return nil
+}

pkg/network/payload/address_test.go

@@ -0,0 +1,51 @@
+package payload
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/CityOfZion/neo-go/pkg/util"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestEncodeDecodeAddress(t *testing.T) {
+	var (
+		e    = util.NewEndpoint("127.0.0.1:2000")
+		addr = NewAddressAndTime(e, time.Now())
+		buf  = new(bytes.Buffer)
+	)
+
+	if err := addr.EncodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	addrDecode := &AddressAndTime{}
+	if err := addrDecode.DecodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, addr, addrDecode)
+}
+
+func TestEncodeDecodeAddressList(t *testing.T) {
+	var lenList uint8 = 4
+	addrList := &AddressList{make([]*AddressAndTime, lenList)}
+	for i := 0; i < int(lenList); i++ {
+		e := util.NewEndpoint(fmt.Sprintf("127.0.0.1:200%d", i))
+		addrList.Addrs[i] = NewAddressAndTime(e, time.Now())
+	}
+
+	buf := new(bytes.Buffer)
+	if err := addrList.EncodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	addrListDecode := &AddressList{}
+	if err := addrListDecode.DecodeBinary(buf); err != nil {
+		t.Fatal(err)
+	}
+
+	assert.Equal(t, addrList, addrListDecode)
+}

pkg/network/payload/headers.go

@@ -37,6 +37,5 @@ func (p *Headers) EncodeBinary(w io.Writer) error {
 			return err
 		}
 	}
-
 	return nil
 }

pkg/network/payload/headers_test.go

@@ -2,11 +2,11 @@ package payload
 
 import (
 	"bytes"
-	"reflect"
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/core"
 	"github.com/CityOfZion/neo-go/pkg/core/transaction"
+	"github.com/stretchr/testify/assert"
 )
 
 func TestHeadersEncodeDecode(t *testing.T) {
@@ -50,7 +50,9 @@ func TestHeadersEncodeDecode(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	if !reflect.DeepEqual(headers, headersDecode) {
+	for i := 0; i < len(headers.Hdrs); i++ {
-		t.Fatalf("expected both header payload to be equal %+v and %+v", headers, headersDecode)
+		assert.Equal(t, headers.Hdrs[i].Version, headersDecode.Hdrs[i].Version)
+		assert.Equal(t, headers.Hdrs[i].Index, headersDecode.Hdrs[i].Index)
+		assert.Equal(t, headers.Hdrs[i].Script, headersDecode.Hdrs[i].Script)
 	}
 }

pkg/network/payload/inventory.go

@@ -35,8 +35,8 @@ func (i InventoryType) Valid() bool {
 // List of valid InventoryTypes.
 const (
 	BlockType     InventoryType = 0x01 // 1
-	TXType                      = 0x02 // 2
+	TXType        InventoryType = 0x02 // 2
-	ConsensusType               = 0xe0 // 224
+	ConsensusType InventoryType = 0xe0 // 224
 )
 
 // Inventory payload

pkg/network/payload/version.go

@@ -44,36 +44,63 @@ func NewVersion(id uint32, p uint16, ua string, h uint32, r bool) *Version {
 
 // DecodeBinary implements the Payload interface.
 func (p *Version) DecodeBinary(r io.Reader) error {
-	err := binary.Read(r, binary.LittleEndian, &p.Version)
+	if err := binary.Read(r, binary.LittleEndian, &p.Version); err != nil {
-	err = binary.Read(r, binary.LittleEndian, &p.Services)
+		return err
-	err = binary.Read(r, binary.LittleEndian, &p.Timestamp)
+	}
-	err = binary.Read(r, binary.LittleEndian, &p.Port)
+	if err := binary.Read(r, binary.LittleEndian, &p.Services); err != nil {
-	err = binary.Read(r, binary.LittleEndian, &p.Nonce)
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &p.Timestamp); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &p.Port); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &p.Nonce); err != nil {
+		return err
+	}
 
 	var lenUA uint8
-	err = binary.Read(r, binary.LittleEndian, &lenUA)
+	if err := binary.Read(r, binary.LittleEndian, &lenUA); err != nil {
-	p.UserAgent = make([]byte, lenUA)
-	err = binary.Read(r, binary.LittleEndian, &p.UserAgent)
-
-	err = binary.Read(r, binary.LittleEndian, &p.StartHeight)
-	err = binary.Read(r, binary.LittleEndian, &p.Relay)
-
 		return err
+	}
+	p.UserAgent = make([]byte, lenUA)
+	if err := binary.Read(r, binary.LittleEndian, &p.UserAgent); err != nil {
+		return err
+	}
+	if err := binary.Read(r, binary.LittleEndian, &p.StartHeight); err != nil {
+		return err
+	}
+	return binary.Read(r, binary.LittleEndian, &p.Relay)
 }
 
 // EncodeBinary implements the Payload interface.
 func (p *Version) EncodeBinary(w io.Writer) error {
-	err := binary.Write(w, binary.LittleEndian, p.Version)
+	if err := binary.Write(w, binary.LittleEndian, p.Version); err != nil {
-	err = binary.Write(w, binary.LittleEndian, p.Services)
-	err = binary.Write(w, binary.LittleEndian, p.Timestamp)
-	err = binary.Write(w, binary.LittleEndian, p.Port)
-	err = binary.Write(w, binary.LittleEndian, p.Nonce)
-	err = binary.Write(w, binary.LittleEndian, uint8(len(p.UserAgent)))
-	err = binary.Write(w, binary.LittleEndian, p.UserAgent)
-	err = binary.Write(w, binary.LittleEndian, p.StartHeight)
-	err = binary.Write(w, binary.LittleEndian, p.Relay)
-
 		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.Services); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.Timestamp); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.Port); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.Nonce); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, uint8(len(p.UserAgent))); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.UserAgent); err != nil {
+		return err
+	}
+	if err := binary.Write(w, binary.LittleEndian, p.StartHeight); err != nil {
+		return err
+	}
+	return binary.Write(w, binary.LittleEndian, p.Relay)
 }
 
 // Size implements the payloader interface.

pkg/network/peer.go

@@ -5,48 +5,12 @@ import (
 	"github.com/CityOfZion/neo-go/pkg/util"
 )
 
-// Peer is the local representation of a remote node. It's an interface that may
+// A Peer is the local representation of a remote peer.
-// be backed by any concrete transport: local, HTTP, tcp.
+// It's an interface that may be backed by any concrete
+// transport.
 type Peer interface {
-	id() uint32
+	Version() *payload.Version
-	addr() util.Endpoint
+	Endpoint() util.Endpoint
-	disconnect()
+	Send(*Message)
-	Send(*Message) error
+	Done() chan struct{}
-	version() *payload.Version
 }
-
-// LocalPeer is the simplest kind of peer, mapped to a server in the
-// same process-space.
-type LocalPeer struct {
-	s        *Server
-	nonce    uint32
-	endpoint util.Endpoint
-	pVersion *payload.Version
-}
-
-// NewLocalPeer return a LocalPeer.
-func NewLocalPeer(s *Server) *LocalPeer {
-	e, _ := util.EndpointFromString("1.1.1.1:1111")
-	return &LocalPeer{endpoint: e, s: s}
-}
-
-func (p *LocalPeer) Send(msg *Message) error {
-	switch msg.commandType() {
-	case cmdVersion:
-		version := msg.Payload.(*payload.Version)
-		return p.s.handleVersionCmd(version, p)
-	case cmdGetAddr:
-		return p.s.handleGetaddrCmd(msg, p)
-	default:
-		return nil
-	}
-}
-
-// Version implements the Peer interface.
-func (p *LocalPeer) version() *payload.Version {
-	return p.pVersion
-}
-
-func (p *LocalPeer) id() uint32          { return p.nonce }
-func (p *LocalPeer) addr() util.Endpoint { return p.endpoint }
-func (p *LocalPeer) disconnect()         {}

pkg/network/protocol.go

@@ -0,0 +1,22 @@
+package network
+
+import (
+	"github.com/CityOfZion/neo-go/pkg/core"
+	"github.com/CityOfZion/neo-go/pkg/network/payload"
+)
+
+// A ProtoHandler is an interface that abstract the implementation
+// of the NEO protocol.
+type ProtoHandler interface {
+	version() *payload.Version
+	handleProto(*Message, Peer)
+}
+
+type protoHandleFunc func(*Message, Peer)
+
+// Noder is anything that implements the NEO protocol
+// and can return the Blockchain object.
+type Noder interface {
+	ProtoHandler
+	blockchain() *core.Blockchain
+}

pkg/network/rpc.go

@@ -1,129 +0,0 @@
-package network
-
-import (
-	"encoding/json"
-	"fmt"
-	"net/http"
-)
-
-const (
-	rpcPortMainNet = 20332
-	rpcPortTestNet = 10332
-	rpcVersion     = "2.0"
-
-	// error response messages
-	methodNotFound = "Method not found"
-	parseError     = "Parse error"
-)
-
-// Each NEO node has a set of optional APIs for accessing blockchain
-// data and making things easier for development of blockchain apps.
-// APIs are provided via JSON-RPC , comm at bottom layer is with http/https protocol.
-
-// listenHTTP creates an ingress bridge from the outside world to the passed
-// server, by installing handlers for all the necessary RPCs to the passed mux.
-func listenHTTP(s *Server, port int) {
-	api := &API{s}
-	p := fmt.Sprintf(":%d", port)
-	s.logger.Printf("serving RPC on %d", port)
-	s.logger.Printf("%s", http.ListenAndServe(p, api))
-}
-
-// API serves JSON-RPC.
-type API struct {
-	s *Server
-}
-
-func (s *API) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	// Official nodes respond a parse error if the method is not POST.
-	// Instead of returning a decent response for this, let's do the same.
-	if r.Method != "POST" {
-		writeError(w, 0, 0, parseError)
-	}
-
-	var req Request
-	if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
-		writeError(w, 0, 0, parseError)
-		return
-	}
-	defer r.Body.Close()
-
-	if req.Version != rpcVersion {
-		writeJSON(w, http.StatusBadRequest, nil)
-		return
-	}
-
-	switch req.Method {
-	case "getconnectioncount":
-		if err := s.getConnectionCount(w, &req); err != nil {
-			writeError(w, 0, 0, parseError)
-			return
-		}
-	case "getblockcount":
-	case "getbestblockhash":
-	default:
-		writeError(w, 0, 0, methodNotFound)
-	}
-}
-
-// This is an Example on how we could handle incomming RPC requests.
-func (s *API) getConnectionCount(w http.ResponseWriter, req *Request) error {
-	count := s.s.peerCount()
-
-	resp := ConnectionCountResponse{
-		Version: rpcVersion,
-		Result:  count,
-		ID:      1,
-	}
-
-	return writeJSON(w, http.StatusOK, resp)
-}
-
-// writeError returns a JSON error with given parameters. All error HTTP
-// status codes are 200. According to the official API.
-func writeError(w http.ResponseWriter, id, code int, msg string) error {
-	resp := RequestError{
-		Version: rpcVersion,
-		ID:      id,
-		Error: Error{
-			Code:    code,
-			Message: msg,
-		},
-	}
-
-	return writeJSON(w, http.StatusOK, resp)
-}
-
-func writeJSON(w http.ResponseWriter, status int, v interface{}) error {
-	w.Header().Set("Content-Type", "application/json")
-	w.WriteHeader(status)
-	return json.NewEncoder(w).Encode(v)
-}
-
-// Request is an object received through JSON-RPC from the client.
-type Request struct {
-	Version string   `json:"jsonrpc"`
-	Method  string   `json:"method"`
-	Params  []string `json:"params"`
-	ID      int      `json:"id"`
-}
-
-// ConnectionCountResponse ..
-type ConnectionCountResponse struct {
-	Version string `json:"jsonrpc"`
-	Result  int    `json:"result"`
-	ID      int    `json:"id"`
-}
-
-// RequestError ..
-type RequestError struct {
-	Version string `json:"jsonrpc"`
-	ID      int    `json:"id"`
-	Error   Error  `json:"error"`
-}
-
-// Error holds information about an RCP error.
-type Error struct {
-	Code    int    `json:"code"`
-	Message string `json:"message"`
-}

pkg/network/server.go

@@ -1,354 +1,282 @@
 package network
 
 import (
-	"context"
-	"errors"
 	"fmt"
-	"log"
 	"net"
 	"os"
-	"sync"
+	"text/tabwriter"
 	"time"
 
-	"github.com/CityOfZion/neo-go/pkg/core"
-	"github.com/CityOfZion/neo-go/pkg/network/payload"
 	"github.com/CityOfZion/neo-go/pkg/util"
+	log "github.com/go-kit/kit/log"
 )
 
 const (
 	// node version
 	version = "2.6.0"
+
 	// official ports according to the protocol.
 	portMainNet = 10333
 	portTestNet = 20333
 	maxPeers    = 50
 )
 
-type messageTuple struct {
+var dialTimeout = 4 * time.Second
-	peer Peer
+
-	msg  *Message
+// Config holds the server configuration.
+type Config struct {
+	// MaxPeers it the maximum numbers of peers that can
+	// be connected to the server.
+	MaxPeers int
+
+	// The user agent of the server.
+	UserAgent string
+
+	// The listen address of the TCP server.
+	ListenTCP uint16
+
+	// The listen address of the RPC server.
+	ListenRPC uint16
+
+	// The network mode this server will operate on.
+	// ModePrivNet docker private network.
+	// ModeTestNet NEO test network.
+	// ModeMainNet NEO main network.
+	Net NetMode
+
+	// Relay determins whether the server is forwarding its inventory.
+	Relay bool
+
+	// Seeds are a list of initial nodes used to establish connectivity.
+	Seeds []string
+
+	// Maximum duration a single dial may take.
+	DialTimeout time.Duration
 }
 
-// Server is the representation of a full working NEO TCP node.
+// Server manages all incoming peer connections.
 type Server struct {
-	logger *log.Logger
+	// Config fields may not be modified while the server is running.
-	// id of the server
+	Config
+
+	// Proto is just about anything that can handle the NEO protocol.
+	// In production enviroments the ProtoHandler is mostly the local node.
+	proto ProtoHandler
+
+	// Unique id of this server.
 	id uint32
-	// the port the TCP listener is listening on.
+
-	port uint16
+	logger   log.Logger
-	// userAgent of the server.
-	userAgent string
-	// The "magic" mode the server is currently running on.
-	// This can either be 0x00746e41 or 0x74746e41 for main or test net.
-	// Or 56753 to work with the docker privnet.
-	net NetMode
-	// map that holds all connected peers to this server.
-	peers map[Peer]bool
-	// channel for handling new registerd peers.
-	register chan Peer
-	// channel for safely removing and disconnecting peers.
-	unregister chan Peer
-	// channel for coordinating messages.
-	message chan messageTuple
-	// channel used to gracefull shutdown the server.
-	quit chan struct{}
-	// Whether this server will receive and forward messages.
-	relay bool
-	// TCP listener of the server
 	listener net.Listener
-	// channel for safely responding the number of current connected peers.
+
-	peerCountCh chan peerCount
+	register   chan Peer
-	// a list of hashes that
+	unregister chan Peer
-	knownHashes protectedHashmap
+
-	// The blockchain.
+	badAddrOp     chan func(map[string]bool)
-	bc *core.Blockchain
+	badAddrOpDone chan struct{}
+
+	peerOp     chan func(map[Peer]bool)
+	peerOpDone chan struct{}
+
+	quit chan struct{}
 }
 
-// TODO: Maybe util is a better place for such data types.
+// NewServer returns a new Server object created from the
-type protectedHashmap struct {
+// given config.
-	*sync.RWMutex
+func NewServer(cfg Config) *Server {
-	hashes map[util.Uint256]bool
+	if cfg.MaxPeers == 0 {
-}
+		cfg.MaxPeers = maxPeers
-
-func (m protectedHashmap) add(h util.Uint256) bool {
-	m.Lock()
-	defer m.Unlock()
-
-	if _, ok := m.hashes[h]; !ok {
-		m.hashes[h] = true
-		return true
 	}
-	return false
+	if cfg.Net == 0 {
-}
+		cfg.Net = ModeTestNet
-
-func (m protectedHashmap) remove(h util.Uint256) bool {
-	m.Lock()
-	defer m.Unlock()
-
-	if _, ok := m.hashes[h]; ok {
-		delete(m.hashes, h)
-		return true
 	}
-	return false
+	if cfg.DialTimeout == 0 {
-}
+		cfg.DialTimeout = dialTimeout
-
-func (m protectedHashmap) has(h util.Uint256) bool {
-	m.RLock()
-	defer m.RUnlock()
-
-	_, ok := m.hashes[h]
-
-	return ok
-}
-
-// NewServer returns a pointer to a new server.
-func NewServer(net NetMode) *Server {
-	logger := log.New(os.Stdout, "[NEO SERVER] :: ", 0)
-
-	if net != ModeTestNet && net != ModeMainNet && net != ModePrivNet {
-		logger.Fatalf("invalid network mode %d", net)
 	}
 
-	// For now I will hard code a genesis block of the docker privnet container.
+	logger := log.NewLogfmtLogger(os.Stderr)
-	startHash, _ := util.Uint256DecodeString("996e37358dc369912041f966f8c5d8d3a8255ba5dcbd3447f8a82b55db869099")
+	logger = log.With(logger, "component", "server")
 
 	s := &Server{
-		id:          util.RandUint32(1111111, 9999999),
+		Config:        cfg,
-		userAgent:   fmt.Sprintf("/NEO:%s/", version),
 		logger:        logger,
-		peers:       make(map[Peer]bool),
+		id:            util.RandUint32(1000000, 9999999),
+		quit:          make(chan struct{}, 1),
 		register:      make(chan Peer),
 		unregister:    make(chan Peer),
-		message:     make(chan messageTuple),
+		badAddrOp:     make(chan func(map[string]bool)),
-		relay:       true, // currently relay is not handled.
+		badAddrOpDone: make(chan struct{}),
-		net:         net,
+		peerOp:        make(chan func(map[Peer]bool)),
-		quit:        make(chan struct{}),
+		peerOpDone:    make(chan struct{}),
-		peerCountCh: make(chan peerCount),
-		bc:          core.NewBlockchain(core.NewMemoryStore(), logger, startHash),
 	}
 
+	s.proto = newNode(s, cfg)
+
 	return s
 }
 
-// Start run's the server.
+func (s *Server) createListener() error {
-// TODO: server should be initialized with a config.
+	ln, err := net.Listen("tcp", fmt.Sprintf(":%d", s.ListenTCP))
-func (s *Server) Start(opts StartOpts) {
-	s.port = uint16(opts.TCP)
-
-	fmt.Println(logo())
-	fmt.Println(string(s.userAgent))
-	fmt.Println("")
-	s.logger.Printf("NET: %s - TCP: %d - RELAY: %v - ID: %d",
-		s.net, int(s.port), s.relay, s.id)
-
-	go listenTCP(s, opts.TCP)
-
-	if opts.RPC > 0 {
-		go listenHTTP(s, opts.RPC)
-	}
-
-	if len(opts.Seeds) > 0 {
-		connectToSeeds(s, opts.Seeds)
-	}
-
-	s.loop()
-}
-
-// Stop the server, attemping a gracefull shutdown.
-func (s *Server) Stop() { s.quit <- struct{}{} }
-
-// shutdown the server, disconnecting all peers.
-func (s *Server) shutdown() {
-	s.logger.Println("attemping a quitefull shutdown.")
-	s.listener.Close()
-
-	// disconnect and remove all connected peers.
-	for peer := range s.peers {
-		peer.disconnect()
-	}
-}
-
-func (s *Server) loop() {
-	for {
-		select {
-		// When a new connection is been established, (by this server or remote node)
-		// its peer will be received on this channel.
-		// Any peer registration must happen via this channel.
-		case peer := <-s.register:
-			if len(s.peers) < maxPeers {
-				s.logger.Printf("peer registered from address %s", peer.addr())
-				s.peers[peer] = true
-
-				if err := s.handlePeerConnected(peer); err != nil {
-					s.logger.Printf("failed handling peer connection: %s", err)
-					peer.disconnect()
-				}
-			}
-
-		// unregister safely deletes a peer. For disconnecting peers use the
-		// disconnect() method on the peer, it will call unregister and terminates its routines.
-		case peer := <-s.unregister:
-			if _, ok := s.peers[peer]; ok {
-				delete(s.peers, peer)
-				s.logger.Printf("peer %s disconnected", peer.addr())
-			}
-
-		case t := <-s.peerCountCh:
-			t.count <- len(s.peers)
-
-		case <-s.quit:
-			s.shutdown()
-		}
-	}
-}
-
-// When a new peer is connected we send our version.
-// No further communication should be made before both sides has received
-// the versions of eachother.
-func (s *Server) handlePeerConnected(p Peer) error {
-	// TODO: get the blockheight of this server once core implemented this.
-	payload := payload.NewVersion(s.id, s.port, s.userAgent, s.bc.HeaderHeight(), s.relay)
-	msg := newMessage(s.net, cmdVersion, payload)
-	return p.Send(msg)
-}
-
-func (s *Server) handleVersionCmd(version *payload.Version, p Peer) error {
-	if s.id == version.Nonce {
-		return errors.New("identical nonce")
-	}
-	if p.addr().Port != version.Port {
-		return fmt.Errorf("port mismatch: %d and %d", version.Port, p.addr().Port)
-	}
-
-	return p.Send(
-		newMessage(s.net, cmdVerack, nil),
-	)
-}
-
-func (s *Server) handleGetaddrCmd(msg *Message, p Peer) error {
-	return nil
-}
-
-// The node can broadcast the object information it owns by this message.
-// The message can be sent automatically or can be used to answer getbloks messages.
-func (s *Server) handleInvCmd(inv *payload.Inventory, p Peer) error {
-	if !inv.Type.Valid() {
-		return fmt.Errorf("invalid inventory type %s", inv.Type)
-	}
-	if len(inv.Hashes) == 0 {
-		return errors.New("inventory should have at least 1 hash got 0")
-	}
-
-	// todo: only grab the hashes that we dont know.
-
-	payload := payload.NewInventory(inv.Type, inv.Hashes)
-	resp := newMessage(s.net, cmdGetData, payload)
-
-	return p.Send(resp)
-}
-
-// handleBlockCmd processes the received block.
-func (s *Server) handleBlockCmd(block *core.Block, p Peer) error {
-	hash, err := block.Hash()
 	if err != nil {
 		return err
 	}
-
+	s.listener = ln
-	s.logger.Printf("new block: index %d hash %s", block.Index, hash)
-
 	return nil
 }
 
-// After receiving the getaddr message, the node returns an addr message as response
+func (s *Server) listenTCP() {
-// and provides information about the known nodes on the network.
-func (s *Server) handleAddrCmd(addrList *payload.AddressList, p Peer) error {
-	for _, addr := range addrList.Addrs {
-		if !s.peerAlreadyConnected(addr.Addr) {
-			// TODO: this is not transport abstracted.
-			go connectToRemoteNode(s, addr.Addr.String())
-		}
-	}
-	return nil
-}
-
-// Handle the headers received from the remote after we asked for headers with the
-// "getheaders" message.
-func (s *Server) handleHeadersCmd(headers *payload.Headers, p Peer) error {
-	// Set a deadline for adding headers?
-	go func(ctx context.Context, headers []*core.Header) {
-		if err := s.bc.AddHeaders(headers...); err != nil {
-			s.logger.Printf("failed to add headers: %s", err)
-			return
-		}
-
-		// Ask more headers if we are not in sync with the peer.
-		if s.bc.HeaderHeight() < p.version().StartHeight {
-			if err := s.askMoreHeaders(p); err != nil {
-				s.logger.Printf("getheaders RPC failed: %s", err)
-				return
-			}
-		}
-	}(context.TODO(), headers.Hdrs)
-
-	return nil
-}
-
-// Ask the peer for more headers We use the current block hash as start.
-func (s *Server) askMoreHeaders(p Peer) error {
-	start := []util.Uint256{s.bc.CurrentHeaderHash()}
-	payload := payload.NewGetBlocks(start, util.Uint256{})
-	msg := newMessage(s.net, cmdGetHeaders, payload)
-
-	return p.Send(msg)
-}
-
-// check if the addr is already connected to the server.
-func (s *Server) peerAlreadyConnected(addr net.Addr) bool {
-	// TODO: Dont try to connect with ourselfs.
-	for peer := range s.peers {
-		if peer.addr().String() == addr.String() {
-			return true
-		}
-	}
-	return false
-}
-
-// TODO: Quit this routine if the peer is disconnected.
-func (s *Server) startProtocol(p Peer) {
-	if s.bc.HeaderHeight() < p.version().StartHeight {
-		s.askMoreHeaders(p)
-	}
 	for {
-		getaddrMsg := newMessage(s.net, cmdGetAddr, nil)
+		conn, err := s.listener.Accept()
-		p.Send(getaddrMsg)
+		if err != nil {
+			s.logger.Log("msg", "conn read error", "err", err)
+			break
+		}
+		go s.setupConnection(conn)
+	}
+	s.Quit()
+}
 
-		time.Sleep(30 * time.Second)
+func (s *Server) setupConnection(conn net.Conn) {
+	if !s.hasCapacity() {
+		s.logger.Log("msg", "server reached maximum capacity")
+		return
+	}
+
+	p := NewTCPPeer(conn, s.proto.handleProto)
+	s.register <- p
+	if err := p.run(); err != nil {
+		s.unregister <- p
 	}
 }
 
-type peerCount struct {
+func (s *Server) connectToPeers(addrs ...string) {
-	count chan int
+	for _, addr := range addrs {
+		if s.hasCapacity() && s.canConnectWith(addr) {
+			go func(addr string) {
+				conn, err := net.DialTimeout("tcp", addr, s.DialTimeout)
+				if err != nil {
+					s.badAddrOp <- func(badAddrs map[string]bool) {
+						badAddrs[addr] = true
+					}
+					<-s.badAddrOpDone
+					return
+				}
+				go s.setupConnection(conn)
+			}(addr)
+		}
+	}
 }
 
-// peerCount returns the number of connected peers to this server.
+func (s *Server) canConnectWith(addr string) bool {
-func (s *Server) peerCount() int {
+	canConnect := true
-	ch := peerCount{
+	s.peerOp <- func(peers map[Peer]bool) {
-		count: make(chan int),
+		for peer := range peers {
+			if peer.Endpoint().String() == addr {
+				canConnect = false
+				break
+			}
+		}
+	}
+	<-s.peerOpDone
+	if !canConnect {
+		return false
 	}
 
-	s.peerCountCh <- ch
+	s.badAddrOp <- func(badAddrs map[string]bool) {
-
+		_, ok := badAddrs[addr]
-	return <-ch.count
+		canConnect = !ok
+	}
+	<-s.badAddrOpDone
+	return canConnect
 }
 
-// StartOpts holds the server configuration.
+func (s *Server) hasCapacity() bool {
-type StartOpts struct {
+	return s.PeerCount() != s.MaxPeers
-	// tcp port
+}
-	TCP int
+
-	// slice of peer addresses the server will connect to
+func (s *Server) sendVersion(peer Peer) {
-	Seeds []string
+	peer.Send(NewMessage(s.Net, CMDVersion, s.proto.version()))
-	// JSON-RPC port. If 0 no RPC handler will be attached.
+}
-	RPC int
+
+func (s *Server) run() {
+	var (
+		ticker   = time.NewTicker(30 * time.Second).C
+		peers    = make(map[Peer]bool)
+		badAddrs = make(map[string]bool)
+	)
+
+	for {
+		select {
+		case op := <-s.badAddrOp:
+			op(badAddrs)
+			s.badAddrOpDone <- struct{}{}
+		case op := <-s.peerOp:
+			op(peers)
+			s.peerOpDone <- struct{}{}
+		case p := <-s.register:
+			peers[p] = true
+			// When a new peer connection is established, we send
+			// out our version immediately.
+			s.sendVersion(p)
+			s.logger.Log("event", "peer connected", "endpoint", p.Endpoint())
+		case p := <-s.unregister:
+			delete(peers, p)
+			s.logger.Log("event", "peer disconnected", "endpoint", p.Endpoint())
+		case <-ticker:
+			s.printState()
+		case <-s.quit:
+			return
+		}
+	}
+}
+
+// PeerCount returns the number of current connected peers.
+func (s *Server) PeerCount() (n int) {
+	s.peerOp <- func(peers map[Peer]bool) {
+		n = len(peers)
+	}
+	<-s.peerOpDone
+	return
+}
+
+func (s *Server) Start() error {
+	fmt.Println(logo())
+	fmt.Println("")
+	s.printConfiguration()
+
+	if err := s.createListener(); err != nil {
+		return err
+	}
+
+	go s.run()
+	go s.listenTCP()
+	go s.connectToPeers(s.Seeds...)
+	select {}
+}
+
+func (s *Server) Quit() {
+	s.quit <- struct{}{}
+}
+
+func (s *Server) printState() {
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
+	fmt.Fprintf(w, "connected peers:\t%d/%d\n", s.PeerCount(), s.MaxPeers)
+	w.Flush()
+}
+
+func (s *Server) printConfiguration() {
+	w := tabwriter.NewWriter(os.Stdout, 0, 0, 4, ' ', 0)
+	fmt.Fprintf(w, "user agent:\t%s\n", s.UserAgent)
+	fmt.Fprintf(w, "id:\t%d\n", s.id)
+	fmt.Fprintf(w, "network:\t%s\n", s.Net)
+	fmt.Fprintf(w, "listen TCP:\t%d\n", s.ListenTCP)
+	fmt.Fprintf(w, "listen RPC:\t%d\n", s.ListenRPC)
+	fmt.Fprintf(w, "relay:\t%v\n", s.Relay)
+	fmt.Fprintf(w, "max peers:\t%d\n", s.MaxPeers)
+	chainer := s.proto.(Noder)
+	fmt.Fprintf(w, "current height:\t%d\n", chainer.blockchain().HeaderHeight())
+	fmt.Fprintln(w, "")
+	w.Flush()
 }
 
 func logo() string {

pkg/network/server_test.go

@@ -1,60 +1,86 @@
 package network
 
 import (
+	"os"
 	"testing"
 
 	"github.com/CityOfZion/neo-go/pkg/network/payload"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	log "github.com/go-kit/kit/log"
+	"github.com/stretchr/testify/assert"
 )
 
-// TODO this should be moved to localPeer test.
+func TestRegisterPeer(t *testing.T) {
+	s := newTestServer()
+	go s.run()
 
-func TestHandleVersionFailWrongPort(t *testing.T) {
+	assert.NotZero(t, s.id)
-	s := NewServer(ModePrivNet)
+	assert.Zero(t, s.PeerCount())
-	go s.loop()
 
-	p := NewLocalPeer(s)
+	lenPeers := 10
+	for i := 0; i < lenPeers; i++ {
+		s.register <- newTestPeer()
+	}
+	assert.Equal(t, lenPeers, s.PeerCount())
+}
 
-	version := payload.NewVersion(1337, 1, "/NEO:0.0.0/", 0, true)
+func TestUnregisterPeer(t *testing.T) {
-	if err := s.handleVersionCmd(version, p); err == nil {
+	s := newTestServer()
-		t.Fatal("expected error got nil")
+	go s.run()
+
+	peer := newTestPeer()
+	s.register <- peer
+	s.register <- newTestPeer()
+	s.register <- newTestPeer()
+	assert.Equal(t, 3, s.PeerCount())
+
+	s.unregister <- peer
+	assert.Equal(t, 2, s.PeerCount())
+}
+
+type testNode struct{}
+
+func (t testNode) version() *payload.Version {
+	return &payload.Version{}
+}
+
+func (t testNode) handleProto(msg *Message, p Peer) {}
+
+func newTestServer() *Server {
+	return &Server{
+		logger:        log.NewLogfmtLogger(os.Stderr),
+		id:            util.RandUint32(1000000, 9999999),
+		quit:          make(chan struct{}, 1),
+		register:      make(chan Peer),
+		unregister:    make(chan Peer),
+		badAddrOp:     make(chan func(map[string]bool)),
+		badAddrOpDone: make(chan struct{}),
+		peerOp:        make(chan func(map[Peer]bool)),
+		peerOpDone:    make(chan struct{}),
+		proto:         testNode{},
 	}
 }
 
-func TestHandleVersionFailIdenticalNonce(t *testing.T) {
+type testPeer struct {
-	s := NewServer(ModePrivNet)
+	done chan struct{}
-	go s.loop()
+}
 
-	p := NewLocalPeer(s)
+func newTestPeer() testPeer {
-
+	return testPeer{
-	version := payload.NewVersion(s.id, 1, "/NEO:0.0.0/", 0, true)
+		done: make(chan struct{}),
-	if err := s.handleVersionCmd(version, p); err == nil {
-		t.Fatal("expected error got nil")
 	}
 }
 
-func TestHandleVersion(t *testing.T) {
+func (p testPeer) Version() *payload.Version {
-	s := NewServer(ModePrivNet)
+	return &payload.Version{}
-	go s.loop()
-
-	p := NewLocalPeer(s)
-
-	version := payload.NewVersion(1337, p.addr().Port, "/NEO:0.0.0/", 0, true)
-	if err := s.handleVersionCmd(version, p); err != nil {
-		t.Fatal(err)
-	}
 }
 
-func TestHandleAddrCmd(t *testing.T) {
+func (p testPeer) Endpoint() util.Endpoint {
-	// todo
+	return util.Endpoint{}
 }
 
-func TestHandleGetAddrCmd(t *testing.T) {
+func (p testPeer) Send(msg *Message) {}
-	// todo
-}
 
-func TestHandleInv(t *testing.T) {
+func (p testPeer) Done() chan struct{} {
-	// todo
+	return p.done
-}
-func TestHandleBlockCmd(t *testing.T) {
-	// todo
 }

pkg/network/tcp.go

@@ -1,254 +0,0 @@
-package network
-
-import (
-	"bytes"
-	"errors"
-	"fmt"
-	"net"
-
-	"github.com/CityOfZion/neo-go/pkg/core"
-	"github.com/CityOfZion/neo-go/pkg/network/payload"
-	"github.com/CityOfZion/neo-go/pkg/util"
-)
-
-func listenTCP(s *Server, port int) error {
-	ln, err := net.Listen("tcp", fmt.Sprintf(":%d", port))
-	if err != nil {
-		return err
-	}
-
-	s.listener = ln
-
-	for {
-		conn, err := ln.Accept()
-		if err != nil {
-			return err
-		}
-
-		go handleConnection(s, conn)
-	}
-}
-
-func connectToRemoteNode(s *Server, address string) {
-	conn, err := net.Dial("tcp", address)
-	if err != nil {
-		s.logger.Printf("failed to connect to remote node %s", address)
-		if conn != nil {
-			conn.Close()
-		}
-		return
-	}
-	go handleConnection(s, conn)
-}
-
-func connectToSeeds(s *Server, addrs []string) {
-	for _, addr := range addrs {
-		go connectToRemoteNode(s, addr)
-	}
-}
-
-func handleConnection(s *Server, conn net.Conn) {
-	peer := NewTCPPeer(conn, s)
-	s.register <- peer
-
-	// remove the peer from connected peers and cleanup the connection.
-	defer func() {
-		peer.disconnect()
-	}()
-
-	// Start a goroutine that will handle all outgoing messages.
-	go peer.writeLoop()
-	// Start a goroutine that will handle all incomming messages.
-	go handleMessage(s, peer)
-
-	// Read from the connection and decode it into a Message ready for processing.
-	for {
-		msg := &Message{}
-		if err := msg.decode(conn); err != nil {
-			s.logger.Printf("decode error: %s", err)
-			break
-		}
-
-		peer.receive <- msg
-	}
-}
-
-// handleMessage multiplexes the message received from a TCP connection to a server command.
-func handleMessage(s *Server, p *TCPPeer) {
-	var err error
-
-	for {
-		msg := <-p.receive
-		command := msg.commandType()
-
-		// s.logger.Printf("IN :: %d :: %s :: %v", p.id(), command, msg)
-
-		switch command {
-		case cmdVersion:
-			version := msg.Payload.(*payload.Version)
-			if err = s.handleVersionCmd(version, p); err != nil {
-				break
-			}
-			p.nonce = version.Nonce
-			p.pVersion = version
-
-			// When a node receives a connection request, it declares its version immediately.
-			// There will be no other communication until both sides are getting versions of each other.
-			// When a node receives the version message, it replies to a verack as a response immediately.
-			// NOTE: The current official NEO nodes dont mimic this behaviour. There is small chance that the
-			// official nodes will not respond directly with a verack after we sended our version.
-			// is this a bug? - anthdm 02/02/2018
-			msgVerack := <-p.receive
-			if msgVerack.commandType() != cmdVerack {
-				err = errors.New("expected verack after sended out version")
-				break
-			}
-
-			// start the protocol
-			go s.startProtocol(p)
-		case cmdAddr:
-			addrList := msg.Payload.(*payload.AddressList)
-			err = s.handleAddrCmd(addrList, p)
-		case cmdGetAddr:
-			err = s.handleGetaddrCmd(msg, p)
-		case cmdInv:
-			inv := msg.Payload.(*payload.Inventory)
-			err = s.handleInvCmd(inv, p)
-		case cmdBlock:
-			block := msg.Payload.(*core.Block)
-			err = s.handleBlockCmd(block, p)
-		case cmdConsensus:
-		case cmdTX:
-		case cmdVerack:
-			// If we receive a verack here we disconnect. We already handled the verack
-			// when we sended our version.
-			err = errors.New("verack already received")
-		case cmdGetHeaders:
-		case cmdGetBlocks:
-		case cmdGetData:
-		case cmdHeaders:
-			headers := msg.Payload.(*payload.Headers)
-			err = s.handleHeadersCmd(headers, p)
-		default:
-			// This command is unknown by the server.
-			err = fmt.Errorf("unknown command received %v", msg.Command)
-			break
-		}
-
-		// catch all errors here and disconnect.
-		if err != nil {
-			s.logger.Printf("processing message failed: %s", err)
-			break
-		}
-	}
-
-	// Disconnect the peer when breaked out of the loop.
-	p.disconnect()
-}
-
-type sendTuple struct {
-	msg *Message
-	err chan error
-}
-
-// TCPPeer represents a remote node, backed by TCP transport.
-type TCPPeer struct {
-	s *Server
-	// nonce (id) of the peer.
-	nonce uint32
-	// underlying TCP connection
-	conn net.Conn
-	// host and port information about this peer.
-	endpoint util.Endpoint
-	// channel to coordinate messages writen back to the connection.
-	send chan sendTuple
-	// channel to receive from underlying connection.
-	receive chan *Message
-	// the version sended out by the peer when connected.
-	pVersion *payload.Version
-}
-
-// NewTCPPeer returns a pointer to a TCP Peer.
-func NewTCPPeer(conn net.Conn, s *Server) *TCPPeer {
-	e, _ := util.EndpointFromString(conn.RemoteAddr().String())
-
-	return &TCPPeer{
-		conn:     conn,
-		send:     make(chan sendTuple),
-		receive:  make(chan *Message),
-		endpoint: e,
-		s:        s,
-	}
-}
-
-// Send needed to implement the network.Peer interface
-// and provide the functionality to send a message to
-// the current peer.
-func (p *TCPPeer) Send(msg *Message) error {
-	t := sendTuple{
-		msg: msg,
-		err: make(chan error),
-	}
-
-	p.send <- t
-
-	return <-t.err
-}
-
-func (p *TCPPeer) version() *payload.Version {
-	return p.pVersion
-}
-
-// id implements the peer interface
-func (p *TCPPeer) id() uint32 {
-	return p.nonce
-}
-
-// endpoint implements the peer interface
-func (p *TCPPeer) addr() util.Endpoint {
-	return p.endpoint
-}
-
-// disconnect disconnects the peer, cleaning up all its resources.
-// 3 goroutines needs to be cleanup (writeLoop, handleConnection and handleMessage)
-func (p *TCPPeer) disconnect() {
-	select {
-	case <-p.send:
-	case <-p.receive:
-	default:
-		close(p.send)
-		close(p.receive)
-		p.s.unregister <- p
-		p.conn.Close()
-	}
-}
-
-// writeLoop writes messages to the underlying TCP connection.
-// A goroutine writeLoop is started for each connection.
-// There should be at most one writer to a connection executing
-// all writes from this goroutine.
-func (p *TCPPeer) writeLoop() {
-	// clean up the connection.
-	defer func() {
-		p.disconnect()
-	}()
-
-	// resuse this buffer
-	buf := new(bytes.Buffer)
-	for {
-		t := <-p.send
-		if t.msg == nil {
-			break // send probably closed.
-		}
-
-		// p.s.logger.Printf("OUT :: %s :: %+v", t.msg.commandType(), t.msg.Payload)
-
-		if err := t.msg.encode(buf); err != nil {
-			t.err <- err
-		}
-		_, err := p.conn.Write(buf.Bytes())
-		t.err <- err
-
-		buf.Reset()
-	}
-}

pkg/network/tcp_peer.go

@@ -0,0 +1,134 @@
+package network
+
+import (
+	"bytes"
+	"net"
+	"os"
+	"time"
+
+	"github.com/CityOfZion/neo-go/pkg/network/payload"
+	"github.com/CityOfZion/neo-go/pkg/util"
+	log "github.com/go-kit/kit/log"
+)
+
+// TCPPeer represents a connected remote node in the
+// network over TCP.
+type TCPPeer struct {
+	// The endpoint of the peer.
+	endpoint util.Endpoint
+
+	// underlying connection.
+	conn net.Conn
+
+	// The version the peer declared when connecting.
+	version *payload.Version
+
+	// connectedAt is the timestamp the peer connected to
+	// the network.
+	connectedAt time.Time
+
+	// handleProto is the handler that will handle the
+	// incoming message along with its peer.
+	handleProto protoHandleFunc
+
+	// Done is used to broadcast this peer has stopped running
+	// and should be removed as reference.
+	done chan struct{}
+	send chan *Message
+
+	logger log.Logger
+}
+
+// NewTCPPeer creates a new peer from a TCP connection.
+func NewTCPPeer(conn net.Conn, fun protoHandleFunc) *TCPPeer {
+	e := util.NewEndpoint(conn.RemoteAddr().String())
+	logger := log.NewLogfmtLogger(os.Stderr)
+	logger = log.With(logger, "component", "peer", "endpoint", e)
+
+	return &TCPPeer{
+		endpoint:    e,
+		conn:        conn,
+		done:        make(chan struct{}),
+		send:        make(chan *Message),
+		logger:      logger,
+		connectedAt: time.Now().UTC(),
+		handleProto: fun,
+	}
+}
+
+// Version implements the Peer interface.
+func (p *TCPPeer) Version() *payload.Version {
+	return p.version
+}
+
+// Endpoint implements the Peer interface.
+func (p *TCPPeer) Endpoint() util.Endpoint {
+	return p.endpoint
+}
+
+// Send implements the Peer interface.
+func (p *TCPPeer) Send(msg *Message) {
+	p.send <- msg
+}
+
+// Done implemnets the Peer interface.
+func (p *TCPPeer) Done() chan struct{} {
+	return p.done
+}
+
+func (p *TCPPeer) run() error {
+	errCh := make(chan error, 1)
+
+	go p.readLoop(errCh)
+	go p.writeLoop(errCh)
+
+	err := <-errCh
+	p.logger.Log("err", err)
+	p.cleanup()
+	return err
+}
+
+func (p *TCPPeer) readLoop(errCh chan error) {
+	for {
+		msg := &Message{}
+		if err := msg.decode(p.conn); err != nil {
+			errCh <- err
+			break
+		}
+		p.handleMessage(msg)
+	}
+}
+
+func (p *TCPPeer) writeLoop(errCh chan error) {
+	buf := new(bytes.Buffer)
+
+	for {
+		msg := <-p.send
+		if err := msg.encode(buf); err != nil {
+			errCh <- err
+			break
+		}
+		if _, err := p.conn.Write(buf.Bytes()); err != nil {
+			errCh <- err
+			break
+		}
+		buf.Reset()
+	}
+}
+
+func (p *TCPPeer) cleanup() {
+	p.conn.Close()
+	close(p.send)
+	p.done <- struct{}{}
+}
+
+func (p *TCPPeer) handleMessage(msg *Message) {
+	switch msg.CommandType() {
+	case CMDVersion:
+		version := msg.Payload.(*payload.Version)
+		p.version = version
+		p.handleProto(msg, p)
+	default:
+		p.handleProto(msg, p)
+	}
+}

pkg/util/endpoint.go

@@ -12,14 +12,11 @@ type Endpoint struct {
 	Port uint16
 }
 
-// EndpointFromString returns an Endpoint from the given string.
+// NewEndpoint creates an Endpoint from the given string.
-// For now this only handles the most simple hostport form.
+func NewEndpoint(s string) (e Endpoint) {
-// e.g. 127.0.0.1:3000
-// This should be enough to work with for now.
-func EndpointFromString(s string) (Endpoint, error) {
 	hostPort := strings.Split(s, ":")
 	if len(hostPort) != 2 {
-		return Endpoint{}, fmt.Errorf("invalid address string: %s", s)
+		return e
 	}
 	host := hostPort[0]
 	port := hostPort[1]
@@ -36,7 +33,7 @@ func EndpointFromString(s string) (Endpoint, error) {
 
 	p, _ := strconv.Atoi(port)
 
-	return Endpoint{buf, uint16(p)}, nil
+	return Endpoint{buf, uint16(p)}
 }
 
 // Network implements the net.Addr interface.

pkg/util/uint256.go

@@ -34,7 +34,7 @@ func Uint256DecodeBytes(b []byte) (u Uint256, err error) {
 	return u, nil
 }
 
-// ToSlice returns a byte slice representation of u.
+// Bytes returns a byte slice representation of u.
 func (u Uint256) Bytes() []byte {
 	b := make([]byte, uint256Size)
 	for i := 0; i < uint256Size; i++ {

pkg/wallet/wif.go

@@ -8,7 +8,7 @@ import (
 )
 
 const (
-	// The WIF network version used to decode and encode WIF keys.
+	// WIFVersion is the version used to decode and encode WIF keys.
 	WIFVersion = 0x80
 )