// Copyright 2016 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
// Package les implements the Light Ethereum Subprotocol.
package les
import (
"errors"
"fmt"
"math/big"
"sync"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/core/types"
"github.com/ethereum/go-ethereum/eth"
"github.com/ethereum/go-ethereum/les/flowcontrol"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/rlp"
)
var (
errClosed = errors.New("peer set is closed")
errAlreadyRegistered = errors.New("peer is already registered")
errNotRegistered = errors.New("peer is not registered")
)
const (
maxHeadInfoLen = 20
maxResponseErrors = 50 // number of invalid responses tolerated (makes the protocol less brittle but still avoids spam)
)
type peer struct {
*p2p.Peer
rw p2p.MsgReadWriter
version int // Protocol version negotiated
network int // Network ID being on
id string
headInfo *announceData
lock sync.RWMutex
announceChn chan announceData
sendQueue *execQueue
poolEntry *poolEntry
hasBlock func(common.Hash, uint64) bool
responseErrors int
fcClient *flowcontrol.ClientNode // nil if the peer is server only
fcServer *flowcontrol.ServerNode // nil if the peer is client only
fcServerParams *flowcontrol.ServerParams
fcCosts requestCostTable
}
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]),
announceChn: make(chan announceData, 20),
}
}
func (p *peer) canQueue() bool {
return p.sendQueue.canQueue()
}
func (p *peer) queueSend(f func()) {
p.sendQueue.queue(f)
}
// Info gathers and returns a collection of metadata known about a peer.
func (p *peer) Info() *eth.PeerInfo {
return ð.PeerInfo{
Version: p.version,
Difficulty: p.Td(),
Head: fmt.Sprintf("%x", p.Head()),
}
}
// 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.headInfo.Hash[:])
return hash
}
func (p *peer) HeadAndTd() (hash common.Hash, td *big.Int) {
p.lock.RLock()
defer p.lock.RUnlock()
copy(hash[:], p.headInfo.Hash[:])
return hash, p.headInfo.Td
}
func (p *peer) headBlockInfo() blockInfo {
p.lock.RLock()
defer p.lock.RUnlock()
return blockInfo{Hash: p.headInfo.Hash, Number: p.headInfo.Number, Td: p.headInfo.Td}
}
// 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.headInfo.Td)
}
// waitBefore implements distPeer interface
func (p *peer) waitBefore(maxCost uint64) (time.Duration, float64) {
return p.fcServer.CanSend(maxCost)
}
func sendRequest(w p2p.MsgWriter, msgcode, reqID, cost uint64, data interface{}) error {
type req struct {
ReqID uint64
Data interface{}
}
return p2p.Send(w, msgcode, req{reqID, data})
}
func sendResponse(w p2p.MsgWriter, msgcode, reqID, bv uint64, data interface{}) error {
type resp struct {
ReqID, BV uint64
Data interface{}
}
return p2p.Send(w, msgcode, resp{reqID, bv, data})
}
func (p *peer) GetRequestCost(msgcode uint64, amount int) uint64 {
p.lock.RLock()
defer p.lock.RUnlock()
cost := p.fcCosts[msgcode].baseCost + p.fcCosts[msgcode].reqCost*uint64(amount)
if cost > p.fcServerParams.BufLimit {
cost = p.fcServerParams.BufLimit
}
return cost
}
// HasBlock checks if the peer has a given block
func (p *peer) HasBlock(hash common.Hash, number uint64) bool {
p.lock.RLock()
hashBlock := p.hasBlock
p.lock.RUnlock()
return hashBlock != nil && hashBlock(hash, number)
}
// SendAnnounce announces the availability of a number of blocks through
// a hash notification.
func (p *peer) SendAnnounce(request announceData) error {
return p2p.Send(p.rw, AnnounceMsg, request)
}
// SendBlockHeaders sends a batch of block headers to the remote peer.
func (p *peer) SendBlockHeaders(reqID, bv uint64, headers []*types.Header) error {
return sendResponse(p.rw, BlockHeadersMsg, reqID, bv, headers)
}
// SendBlockBodiesRLP sends a batch of block contents to the remote peer from
// an already RLP encoded format.
func (p *peer) SendBlockBodiesRLP(reqID, bv uint64, bodies []rlp.RawValue) error {
return sendResponse(p.rw, BlockBodiesMsg, reqID, bv, bodies)
}
// SendCodeRLP sends a batch of arbitrary internal data, corresponding to the
// hashes requested.
func (p *peer) SendCode(reqID, bv uint64, data [][]byte) error {
return sendResponse(p.rw, CodeMsg, reqID, bv, data)
}
// SendReceiptsRLP sends a batch of transaction receipts, corresponding to the
// ones requested from an already RLP encoded format.
func (p *peer) SendReceiptsRLP(reqID, bv uint64, receipts []rlp.RawValue) error {
return sendResponse(p.rw, ReceiptsMsg, reqID, bv, receipts)
}
// SendProofs sends a batch of merkle proofs, corresponding to the ones requested.
func (p *peer) SendProofs(reqID, bv uint64, proofs proofsData) error {
return sendResponse(p.rw, ProofsMsg, reqID, bv, proofs)
}
// SendHeaderProofs sends a batch of header proofs, corresponding to the ones requested.
func (p *peer) SendHeaderProofs(reqID, bv uint64, proofs []ChtResp) error {
return sendResponse(p.rw, HeaderProofsMsg, reqID, bv, proofs)
}
// RequestHeadersByHash fetches a batch of blocks' headers corresponding to the
// specified header query, based on the hash of an origin block.
func (p *peer) RequestHeadersByHash(reqID, cost uint64, origin common.Hash, amount int, skip int, reverse bool) error {
p.Log().Debug("Fetching batch of headers", "count", amount, "fromhash", origin, "skip", skip, "reverse", reverse)
return sendRequest(p.rw, GetBlockHeadersMsg, reqID, cost, &getBlockHeadersData{Origin: hashOrNumber{Hash: origin}, Amount: uint64(amount), Skip: uint64(skip), Reverse: reverse})
}
// RequestHeadersByNumber fetches a batch of blocks' headers corresponding to the
// specified header query, based on the number of an origin block.
func (p *peer) RequestHeadersByNumber(reqID, cost, origin uint64, amount int, skip int, reverse bool) error {
p.Log().Debug("Fetching batch of headers", "count", amount, "fromnum", origin, "skip", skip, "reverse", reverse)
return sendRequest(p.rw, GetBlockHeadersMsg, reqID, cost, &getBlockHeadersData{Origin: hashOrNumber{Number: origin}, Amount: uint64(amount), Skip: uint64(skip), Reverse: reverse})
}
// RequestBodies fetches a batch of blocks' bodies corresponding to the hashes
// specified.
func (p *peer) RequestBodies(reqID, cost uint64, hashes []common.Hash) error {
p.Log().Debug("Fetching batch of block bodies", "count", len(hashes))
return sendRequest(p.rw, GetBlockBodiesMsg, reqID, cost, hashes)
}
// RequestCode fetches a batch of arbitrary data from a node's known state
// data, corresponding to the specified hashes.
func (p *peer) RequestCode(reqID, cost uint64, reqs []*CodeReq) error {
p.Log().Debug("Fetching batch of codes", "count", len(reqs))
return sendRequest(p.rw, GetCodeMsg, reqID, cost, reqs)
}
// RequestReceipts fetches a batch of transaction receipts from a remote node.
func (p *peer) RequestReceipts(reqID, cost uint64, hashes []common.Hash) error {
p.Log().Debug("Fetching batch of receipts", "count", len(hashes))
return sendRequest(p.rw, GetReceiptsMsg, reqID, cost, hashes)
}
// RequestProofs fetches a batch of merkle proofs from a remote node.
func (p *peer) RequestProofs(reqID, cost uint64, reqs []*ProofReq) error {
p.Log().Debug("Fetching batch of proofs", "count", len(reqs))
return sendRequest(p.rw, GetProofsMsg, reqID, cost, reqs)
}
// RequestHeaderProofs fetches a batch of header merkle proofs from a remote node.
func (p *peer) RequestHeaderProofs(reqID, cost uint64, reqs []*ChtReq) error {
p.Log().Debug("Fetching batch of header proofs", "count", len(reqs))
return sendRequest(p.rw, GetHeaderProofsMsg, reqID, cost, reqs)
}
func (p *peer) SendTxs(reqID, cost uint64, txs types.Transactions) error {
p.Log().Debug("Fetching batch of transactions", "count", len(txs))
return p2p.Send(p.rw, SendTxMsg, txs)
}
type keyValueEntry struct {
Key string
Value rlp.RawValue
}
type keyValueList []keyValueEntry
type keyValueMap map[string]rlp.RawValue
func (l keyValueList) add(key string, val interface{}) keyValueList {
var entry keyValueEntry
entry.Key = key
if val == nil {
val = uint64(0)
}
enc, err := rlp.EncodeToBytes(val)
if err == nil {
entry.Value = enc
}
return append(l, entry)
}
func (l keyValueList) decode() keyValueMap {
m := make(keyValueMap)
for _, entry := range l {
m[entry.Key] = entry.Value
}
return m
}
func (m keyValueMap) get(key string, val interface{}) error {
enc, ok := m[key]
if !ok {
return errResp(ErrHandshakeMissingKey, "%s", key)
}
if val == nil {
return nil
}
return rlp.DecodeBytes(enc, val)
}
func (p *peer) sendReceiveHandshake(sendList keyValueList) (keyValueList, error) {
// Send out own handshake in a new thread
errc := make(chan error, 1)
go func() {
errc <- p2p.Send(p.rw, StatusMsg, sendList)
}()
// In the mean time retrieve the remote status message
msg, err := p.rw.ReadMsg()
if err != nil {
return nil, err
}
if msg.Code != StatusMsg {
return nil, errResp(ErrNoStatusMsg, "first msg has code %x (!= %x)", msg.Code, StatusMsg)
}
if msg.Size > ProtocolMaxMsgSize {
return nil, errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
}
// Decode the handshake
var recvList keyValueList
if err := msg.Decode(&recvList); err != nil {
return nil, errResp(ErrDecode, "msg %v: %v", msg, err)
}
if err := <-errc; err != nil {
return nil, err
}
return recvList, nil
}
// Handshake executes the les protocol handshake, negotiating version number,
// network IDs, difficulties, head and genesis blocks.
func (p *peer) Handshake(td *big.Int, head common.Hash, headNum uint64, genesis common.Hash, server *LesServer) error {
p.lock.Lock()
defer p.lock.Unlock()
var send keyValueList
send = send.add("protocolVersion", uint64(p.version))
send = send.add("networkId", uint64(p.network))
send = send.add("headTd", td)
send = send.add("headHash", head)
send = send.add("headNum", headNum)
send = send.add("genesisHash", genesis)
if server != nil {
send = send.add("serveHeaders", nil)
send = send.add("serveChainSince", uint64(0))
send = send.add("serveStateSince", uint64(0))
send = send.add("txRelay", nil)
send = send.add("flowControl/BL", server.defParams.BufLimit)
send = send.add("flowControl/MRR", server.defParams.MinRecharge)
list := server.fcCostStats.getCurrentList()
send = send.add("flowControl/MRC", list)
p.fcCosts = list.decode()
}
recvList, err := p.sendReceiveHandshake(send)
if err != nil {
return err
}
recv := recvList.decode()
var rGenesis, rHash common.Hash
var rVersion, rNetwork, rNum uint64
var rTd *big.Int
if err := recv.get("protocolVersion", &rVersion); err != nil {
return err
}
if err := recv.get("networkId", &rNetwork); err != nil {
return err
}
if err := recv.get("headTd", &rTd); err != nil {
return err
}
if err := recv.get("headHash", &rHash); err != nil {
return err
}
if err := recv.get("headNum", &rNum); err != nil {
return err
}
if err := recv.get("genesisHash", &rGenesis); err != nil {
return err
}
if rGenesis != genesis {
return errResp(ErrGenesisBlockMismatch, "%x (!= %x)", rGenesis[:8], genesis[:8])
}
if int(rNetwork) != p.network {
return errResp(ErrNetworkIdMismatch, "%d (!= %d)", rNetwork, p.network)
}
if int(rVersion) != p.version {
return errResp(ErrProtocolVersionMismatch, "%d (!= %d)", rVersion, p.version)
}
if server != nil {
// until we have a proper peer connectivity API, allow LES connection to other servers
/*if recv.get("serveStateSince", nil) == nil {
return errResp(ErrUselessPeer, "wanted client, got server")
}*/
p.fcClient = flowcontrol.NewClientNode(server.fcManager, server.defParams)
} else {
if recv.get("serveChainSince", nil) != nil {
return errResp(ErrUselessPeer, "peer cannot serve chain")
}
if recv.get("serveStateSince", nil) != nil {
return errResp(ErrUselessPeer, "peer cannot serve state")
}
if recv.get("txRelay", nil) != nil {
return errResp(ErrUselessPeer, "peer cannot relay transactions")
}
params := &flowcontrol.ServerParams{}
if err := recv.get("flowControl/BL", ¶ms.BufLimit); err != nil {
return err
}
if err := recv.get("flowControl/MRR", ¶ms.MinRecharge); err != nil {
return err
}
var MRC RequestCostList
if err := recv.get("flowControl/MRC", &MRC); err != nil {
return err
}
p.fcServerParams = params
p.fcServer = flowcontrol.NewServerNode(params)
p.fcCosts = MRC.decode()
}
p.headInfo = &announceData{Td: rTd, Hash: rHash, Number: rNum}
return nil
}
// String implements fmt.Stringer.
func (p *peer) String() string {
return fmt.Sprintf("Peer %s [%s]", p.id,
fmt.Sprintf("les/%d", p.version),
)
}
// peerSet represents the collection of active peers currently participating in
// the Light Ethereum sub-protocol.
type peerSet struct {
peers map[string]*peer
lock sync.RWMutex
closed bool
}
// 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 ps.closed {
return errClosed
}
if _, ok := ps.peers[p.id]; ok {
return errAlreadyRegistered
}
ps.peers[p.id] = p
p.sendQueue = newExecQueue(100)
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 p, ok := ps.peers[id]; !ok {
return errNotRegistered
} else {
p.sendQueue.quit()
}
delete(ps.peers, id)
return nil
}
// AllPeerIDs returns a list of all registered peer IDs
func (ps *peerSet) AllPeerIDs() []string {
ps.lock.RLock()
defer ps.lock.RUnlock()
res := make([]string, len(ps.peers))
idx := 0
for id := range ps.peers {
res[idx] = id
idx++
}
return res
}
// 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)
}
// 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
}
// AllPeers returns all peers in a list
func (ps *peerSet) AllPeers() []*peer {
ps.lock.RLock()
defer ps.lock.RUnlock()
list := make([]*peer, len(ps.peers))
i := 0
for _, peer := range ps.peers {
list[i] = peer
i++
}
return list
}
// Close disconnects all peers.
// No new peers can be registered after Close has returned.
func (ps *peerSet) Close() {
ps.lock.Lock()
defer ps.lock.Unlock()
for _, p := range ps.peers {
p.Disconnect(p2p.DiscQuitting)
}
ps.closed = true
}
