PoC 6 networking code.

* Added block pool for gathering blocks from the network (chunks)
* Re wrote syncing

block_pool.go

+package eth
+
+import (
+	"math"
+	"math/big"
+	"sync"
+
+	"github.com/ethereum/eth-go/ethchain"
+	"github.com/ethereum/eth-go/ethutil"
+)
+
+type block struct {
+	peer  *Peer
+	block *ethchain.Block
+}
+
+type BlockPool struct {
+	mut sync.Mutex
+
+	eth *Ethereum
+
+	hashPool [][]byte
+	pool     map[string]*block
+
+	td *big.Int
+}
+
+func NewBlockPool(eth *Ethereum) *BlockPool {
+	return &BlockPool{
+		eth:  eth,
+		pool: make(map[string]*block),
+		td:   ethutil.Big0,
+	}
+}
+
+func (self *BlockPool) HasLatestHash() bool {
+	return self.pool[string(self.eth.BlockChain().CurrentBlock.Hash())] != nil
+}
+
+func (self *BlockPool) HasCommonHash(hash []byte) bool {
+	return self.eth.BlockChain().GetBlock(hash) != nil
+}
+
+func (self *BlockPool) AddHash(hash []byte) {
+	if self.pool[string(hash)] == nil {
+		self.pool[string(hash)] = &block{nil, nil}
+
+		self.hashPool = append([][]byte{hash}, self.hashPool...)
+	}
+}
+
+func (self *BlockPool) SetBlock(b *ethchain.Block) {
+	hash := string(b.Hash())
+
+	if self.pool[string(hash)] == nil {
+		self.pool[hash] = &block{nil, nil}
+	}
+
+	self.pool[hash].block = b
+}
+
+func (self *BlockPool) CheckLinkAndProcess(f func(block *ethchain.Block)) bool {
+	self.mut.Lock()
+	defer self.mut.Unlock()
+
+	if self.IsLinked() {
+		for i, hash := range self.hashPool {
+			block := self.pool[string(hash)].block
+			if block != nil {
+				f(block)
+
+				delete(self.pool, string(hash))
+			} else {
+				self.hashPool = self.hashPool[i:]
+
+				return false
+			}
+		}
+
+		return true
+	}
+
+	return false
+}
+
+func (self *BlockPool) IsLinked() bool {
+	if len(self.hashPool) == 0 {
+		return false
+	}
+
+	block := self.pool[string(self.hashPool[0])].block
+	if block != nil {
+		return self.eth.BlockChain().HasBlock(block.PrevHash)
+	}
+
+	return false
+}
+
+func (self *BlockPool) Take(amount int, peer *Peer) (hashes [][]byte) {
+	self.mut.Lock()
+	defer self.mut.Unlock()
+
+	num := int(math.Min(float64(amount), float64(len(self.pool))))
+	j := 0
+	for i := 0; i < len(self.hashPool) && j < num; i++ {
+		hash := string(self.hashPool[i])
+		if self.pool[hash].peer == nil || self.pool[hash].peer == peer {
+			self.pool[hash].peer = peer
+
+			hashes = append(hashes, self.hashPool[i])
+			j++
+		}
+	}
+
+	return
+}

ethchain/block_chain.go

@@ -208,6 +208,26 @@ func (bc *BlockChain) GenesisBlock() *Block {
 	return bc.genesisBlock
 }
 
+func (self *BlockChain) GetChainHashesFromHash(hash []byte, max uint64) (chain [][]byte) {
+	block := self.GetBlock(hash)
+	if block == nil {
+		return
+	}
+
+	// XXX Could be optimised by using a different database which only holds hashes (i.e., linked list)
+	for i := uint64(0); i < max; i++ {
+		chain = append(chain, block.Hash())
+
+		if block.Number.Cmp(ethutil.Big0) <= 0 {
+			break
+		}
+
+		block = self.GetBlock(block.PrevHash)
+	}
+
+	return
+}
+
 // Get chain return blocks from hash up to max in RLP format
 func (bc *BlockChain) GetChainFromHash(hash []byte, max uint64) []interface{} {
 	var chain []interface{}

ethchain/genesis.go

 package ethchain
 
 import (
+	"math/big"
+
 	"github.com/ethereum/eth-go/ethcrypto"
 	"github.com/ethereum/eth-go/ethutil"
-	"math/big"
 )
 
 /*
@@ -26,7 +27,8 @@ var GenesisHeader = []interface{}{
 	// tx sha
 	"",
 	// Difficulty
-	ethutil.BigPow(2, 22),
+	//ethutil.BigPow(2, 22),
+	big.NewInt(4096),
 	// Number
 	ethutil.Big0,
 	// Block minimum gas price

ethereum.go

@@ -54,6 +54,8 @@ type Ethereum struct {
 	txPool *ethchain.TxPool
 	// The canonical chain
 	blockChain *ethchain.BlockChain
+	// The block pool
+	blockPool *BlockPool
 	// Peers (NYI)
 	peers *list.List
 	// Nonce
@@ -116,6 +118,7 @@ func New(db ethutil.Database, clientIdentity ethwire.ClientIdentity, keyManager
 	}
 	ethereum.reactor = ethreact.New()
 
+	ethereum.blockPool = NewBlockPool(ethereum)
 	ethereum.txPool = ethchain.NewTxPool(ethereum)
 	ethereum.blockChain = ethchain.NewBlockChain(ethereum)
 	ethereum.stateManager = ethchain.NewStateManager(ethereum)

ethutil/bytes.go

@@ -208,3 +208,11 @@ func Address(slice []byte) (addr []byte) {
 
 	return
 }
+
+func ByteSliceToInterface(slice [][]byte) (ret []interface{}) {
+	for _, i := range slice {
+		ret = append(ret, i)
+	}
+
+	return
+}

ethwire/messaging.go

@@ -27,33 +27,41 @@ const (
 	// Values are given explicitly instead of by iota because these values are
 	// defined by the wire protocol spec; it is easier for humans to ensure
 	// correctness when values are explicit.
-	MsgHandshakeTy  = 0x00
-	MsgDiscTy       = 0x01
-	MsgPingTy       = 0x02
-	MsgPongTy       = 0x03
-	MsgGetPeersTy   = 0x10
-	MsgPeersTy      = 0x11
-	MsgTxTy         = 0x12
-	MsgBlockTy      = 0x13
-	MsgGetChainTy   = 0x14
-	MsgNotInChainTy = 0x15
-	MsgGetTxsTy     = 0x16
+	MsgHandshakeTy      = 0x00
+	MsgDiscTy           = 0x01
+	MsgPingTy           = 0x02
+	MsgPongTy           = 0x03
+	MsgGetPeersTy       = 0x10
+	MsgPeersTy          = 0x11
+	MsgTxTy             = 0x12
+	MsgGetChainTy       = 0x14
+	MsgNotInChainTy     = 0x15
+	MsgGetTxsTy         = 0x16
+	MsgGetBlockHashesTy = 0x17
+	MsgBlockHashesTy    = 0x18
+	MsgGetBlocksTy      = 0x19
+	MsgBlockTy          = 0x13
+
+	MsgOldBlockTy = 0xbb
 
 	MsgTalkTy = 0xff
 )
 
 var msgTypeToString = map[MsgType]string{
-	MsgHandshakeTy:  "Handshake",
-	MsgDiscTy:       "Disconnect",
-	MsgPingTy:       "Ping",
-	MsgPongTy:       "Pong",
-	MsgGetPeersTy:   "Get peers",
-	MsgPeersTy:      "Peers",
-	MsgTxTy:         "Transactions",
-	MsgBlockTy:      "Blocks",
-	MsgGetChainTy:   "Get chain",
-	MsgGetTxsTy:     "Get Txs",
-	MsgNotInChainTy: "Not in chain",
+	MsgHandshakeTy:      "Handshake",
+	MsgDiscTy:           "Disconnect",
+	MsgPingTy:           "Ping",
+	MsgPongTy:           "Pong",
+	MsgGetPeersTy:       "Get peers",
+	MsgPeersTy:          "Peers",
+	MsgTxTy:             "Transactions",
+	MsgBlockTy:          "Blocks",
+	MsgGetChainTy:       "Get chain",
+	MsgGetTxsTy:         "Get Txs",
+	MsgNotInChainTy:     "Not in chain",
+	MsgGetBlockHashesTy: "Get block hashes",
+	MsgBlockHashesTy:    "Block hashes",
+	MsgGetBlocksTy:      "Get blocks",
 }
 
 func (mt MsgType) String() string {