package eth
import (
"errors"
"fmt"
"math/big"
"sync"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/eth/downloader"
"github.com/ethereum/go-ethereum/logger"
"github.com/ethereum/go-ethereum/logger/glog"
"github.com/ethereum/go-ethereum/p2p"
"gopkg.in/fatih/set.v0"
)
var (
errAlreadyRegistered = errors.New("peer is already registered")
errNotRegistered = errors.New("peer is not registered")
)
const (
maxKnownTxs = 32768 // Maximum transactions hashes to keep in the known list (prevent DOS)
maxKnownBlocks = 1024 // Maximum block hashes to keep in the known list (prevent DOS)
)
type peer struct {
*p2p.Peer
rw p2p.MsgReadWriter
version int // Protocol version negotiated
network int // Network ID being on
id string
head common.Hash
td *big.Int
lock sync.RWMutex
knownTxs *set.Set // Set of transaction hashes known to be known by this peer
knownBlocks *set.Set // Set of block hashes known to be known by this peer
}
func newPeer(version, network int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
id := p.ID()
return &peer{
Peer: p,
rw: rw,
version: version,
network: network,
id: fmt.Sprintf("%x", id[:8]),
knownTxs: set.New(),
knownBlocks: set.New(),
}
}
// Head retrieves a copy of the current head (most recent) hash of the peer.
func (p *peer) Head() (hash common.Hash) {
p.lock.RLock()
defer p.lock.RUnlock()
copy(hash[:], p.head[:])
return hash
}
// SetHead updates the head (most recent) hash of the peer.
func (p *peer) SetHead(hash common.Hash) {
p.lock.Lock()
defer p.lock.Unlock()
copy(p.head[:], hash[:])
}
// Td retrieves the current total difficulty of a peer.
func (p *peer) Td() *big.Int {
p.lock.RLock()
defer p.lock.RUnlock()
return new(big.Int).Set(p.td)
}
// SetTd updates the current total difficulty of a peer.
func (p *peer) SetTd(td *big.Int) {
p.lock.Lock()
defer p.lock.Unlock()
p.td.Set(td)
}
// MarkBlock marks a block as known for the peer, ensuring that the block will
// never be propagated to this particular peer.
func (p *peer) MarkBlock(hash common.Hash) {
// If we reached the memory allowance, drop a previously known block hash
for p.knownBlocks.Size() >= maxKnownBlocks {
p.knownBlocks.Pop()
}
p.knownBlocks.Add(hash)
}
// MarkTransaction marks a transaction as known for the peer, ensuring that it
// will never be propagated to this particular peer.
func (p *peer) MarkTransaction(hash common.Hash) {
// If we reached the memory allowance, drop a previously known transaction hash
for p.knownTxs.Size() >= maxKnownTxs {
p.knownTxs.Pop()
}
p.knownTxs.Add(hash)
}
// SendTransactions sends transactions to the peer and includes the hashes
// in its transaction hash set for future reference.
func (p *peer) SendTransactions(txs types.Transactions) error {
propTxnOutPacketsMeter.Mark(1)
for _, tx := range txs {
propTxnOutTrafficMeter.Mark(tx.Size().Int64())
p.knownTxs.Add(tx.Hash())
}
return p2p.Send(p.rw, TxMsg, txs)
}
// SendBlockHashes sends a batch of known hashes to the remote peer.
func (p *peer) SendBlockHashes(hashes []common.Hash) error {
reqHashOutPacketsMeter.Mark(1)
reqHashOutTrafficMeter.Mark(int64(32 * len(hashes)))
return p2p.Send(p.rw, BlockHashesMsg, hashes)
}
// SendBlocks sends a batch of blocks to the remote peer.
func (p *peer) SendBlocks(blocks []*types.Block) error {
reqBlockOutPacketsMeter.Mark(1)
for _, block := range blocks {
reqBlockOutTrafficMeter.Mark(block.Size().Int64())
}
return p2p.Send(p.rw, BlocksMsg, blocks)
}
// SendNewBlockHashes announces the availability of a number of blocks through
// a hash notification.
func (p *peer) SendNewBlockHashes(hashes []common.Hash) error {
propHashOutPacketsMeter.Mark(1)
propHashOutTrafficMeter.Mark(int64(32 * len(hashes)))
for _, hash := range hashes {
p.knownBlocks.Add(hash)
}
return p2p.Send(p.rw, NewBlockHashesMsg, hashes)
}
// SendNewBlock propagates an entire block to a remote peer.
func (p *peer) SendNewBlock(block *types.Block) error {
propBlockOutPacketsMeter.Mark(1)
propBlockOutTrafficMeter.Mark(block.Size().Int64())
p.knownBlocks.Add(block.Hash())
return p2p.Send(p.rw, NewBlockMsg, []interface{}{block, block.Td})
}
// RequestHashes fetches a batch of hashes from a peer, starting at from, going
// towards the genesis block.
func (p *peer) RequestHashes(from common.Hash) error {
glog.V(logger.Debug).Infof("Peer [%s] fetching hashes (%d) from %x...\n", p.id, downloader.MaxHashFetch, from[:4])
return p2p.Send(p.rw, GetBlockHashesMsg, getBlockHashesData{from, uint64(downloader.MaxHashFetch)})
}
// RequestHashesFromNumber fetches a batch of hashes from a peer, starting at the
// requested block number, going upwards towards the genesis block.
func (p *peer) RequestHashesFromNumber(from uint64, count int) error {
glog.V(logger.Debug).Infof("Peer [%s] fetching hashes (%d) from #%d...\n", p.id, count, from)
return p2p.Send(p.rw, GetBlockHashesFromNumberMsg, getBlockHashesFromNumberData{from, uint64(count)})
}
// RequestBlocks fetches a batch of blocks corresponding to the specified hashes.
func (p *peer) RequestBlocks(hashes []common.Hash) error {
glog.V(logger.Debug).Infof("[%s] fetching %v blocks\n", p.id, len(hashes))
return p2p.Send(p.rw, GetBlocksMsg, hashes)
}
// Handshake executes the eth protocol handshake, negotiating version number,
// network IDs, difficulties, head and genesis blocks.
func (p *peer) Handshake(td *big.Int, head common.Hash, genesis common.Hash) error {
// Send out own handshake in a new thread
errc := make(chan error, 1)
go func() {
errc <- p2p.Send(p.rw, StatusMsg, &statusData{
ProtocolVersion: uint32(p.version),
NetworkId: uint32(p.network),
TD: td,
CurrentBlock: head,
GenesisBlock: genesis,
})
}()
// In the mean time retrieve the remote status message
msg, err := p.rw.ReadMsg()
if err != nil {
return err
}
if msg.Code != StatusMsg {
return errResp(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
}
if msg.Size > ProtocolMaxMsgSize {
return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
// Decode the handshake and make sure everything matches
var status statusData
if err := msg.Decode(&status); err != nil {
return errResp(ErrDecode, "msg %v: %v", msg, err)
}
if status.GenesisBlock != genesis {
return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", status.GenesisBlock, genesis)
}
if int(status.NetworkId) != p.network {
return errResp(ErrNetworkIdMismatch, "%d (!= %d)", status.NetworkId, p.network)
}
if int(status.ProtocolVersion) != p.version {
return errResp(ErrProtocolVersionMismatch, "%d (!= %d)", status.ProtocolVersion, p.version)
}
// Configure the remote peer, and sanity check out handshake too
p.td, p.head = status.TD, status.CurrentBlock
return <-errc
}
// String implements fmt.Stringer.
func (p *peer) String() string {
return fmt.Sprintf("Peer %s [%s]", p.id,
fmt.Sprintf("eth/%2d", p.version),
)
}
// peerSet represents the collection of active peers currently participating in
// the Ethereum sub-protocol.
type peerSet struct {
peers map[string]*peer
lock sync.RWMutex
}
// newPeerSet creates a new peer set to track the active participants.
func newPeerSet() *peerSet {
return &peerSet{
peers: make(map[string]*peer),
}
}
// Register injects a new peer into the working set, or returns an error if the
// peer is already known.
func (ps *peerSet) Register(p *peer) error {
ps.lock.Lock()
defer ps.lock.Unlock()
if _, ok := ps.peers[p.id]; ok {
return errAlreadyRegistered
}
ps.peers[p.id] = p
return nil
}
// Unregister removes a remote peer from the active set, disabling any further
// actions to/from that particular entity.
func (ps *peerSet) Unregister(id string) error {
ps.lock.Lock()
defer ps.lock.Unlock()
if _, ok := ps.peers[id]; !ok {
return errNotRegistered
}
delete(ps.peers, id)
return nil
}
// Peer retrieves the registered peer with the given id.
func (ps *peerSet) Peer(id string) *peer {
ps.lock.RLock()
defer ps.lock.RUnlock()
return ps.peers[id]
}
// Len returns if the current number of peers in the set.
func (ps *peerSet) Len() int {
ps.lock.RLock()
defer ps.lock.RUnlock()
return len(ps.peers)
}
// PeersWithoutBlock retrieves a list of peers that do not have a given block in
// their set of known hashes.
func (ps *peerSet) PeersWithoutBlock(hash common.Hash) []*peer {
ps.lock.RLock()
defer ps.lock.RUnlock()
list := make([]*peer, 0, len(ps.peers))
for _, p := range ps.peers {
if !p.knownBlocks.Has(hash) {
list = append(list, p)
}
}
return list
}
// PeersWithoutTx retrieves a list of peers that do not have a given transaction
// in their set of known hashes.
func (ps *peerSet) PeersWithoutTx(hash common.Hash) []*peer {
ps.lock.RLock()
defer ps.lock.RUnlock()
list := make([]*peer, 0, len(ps.peers))
for _, p := range ps.peers {
if !p.knownTxs.Has(hash) {
list = append(list, p)
}
}
return list
}
// BestPeer retrieves the known peer with the currently highest total difficulty.
func (ps *peerSet) BestPeer() *peer {
ps.lock.RLock()
defer ps.lock.RUnlock()
var (
bestPeer *peer
bestTd *big.Int
)
for _, p := range ps.peers {
if td := p.Td(); bestPeer == nil || td.Cmp(bestTd) > 0 {
bestPeer, bestTd = p, td
}
}
return bestPeer
}
