plugeth/les/peer.go
2019-12-25 02:06:00 +01:00

927 lines
27 KiB
Go

// 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
import (
"errors"
"fmt"
"math/big"
"math/rand"
"net"
"sync"
"sync/atomic"
"time"
"github.com/ethereum/go-ethereum/common"
"github.com/ethereum/go-ethereum/common/mclock"
"github.com/ethereum/go-ethereum/core"
"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/light"
"github.com/ethereum/go-ethereum/p2p"
"github.com/ethereum/go-ethereum/p2p/enode"
"github.com/ethereum/go-ethereum/params"
"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 (
maxRequestErrors = 20 // number of invalid requests tolerated (makes the protocol less brittle but still avoids spam)
maxResponseErrors = 50 // number of invalid responses tolerated (makes the protocol less brittle but still avoids spam)
)
// capacity limitation for parameter updates
const (
allowedUpdateBytes = 100000 // initial/maximum allowed update size
allowedUpdateRate = time.Millisecond * 10 // time constant for recharging one byte of allowance
)
const (
freezeTimeBase = time.Millisecond * 700 // fixed component of client freeze time
freezeTimeRandom = time.Millisecond * 600 // random component of client freeze time
freezeCheckPeriod = time.Millisecond * 100 // buffer value recheck period after initial freeze time has elapsed
)
// if the total encoded size of a sent transaction batch is over txSizeCostLimit
// per transaction then the request cost is calculated as proportional to the
// encoded size instead of the transaction count
const txSizeCostLimit = 0x4000
const (
announceTypeNone = iota
announceTypeSimple
announceTypeSigned
)
type peer struct {
*p2p.Peer
rw p2p.MsgReadWriter
version int // Protocol version negotiated
network uint64 // Network ID being on
announceType uint64
// Checkpoint relative fields
checkpoint params.TrustedCheckpoint
checkpointNumber uint64
id string
headInfo *announceData
lock sync.RWMutex
sendQueue *execQueue
errCh chan error
// responseLock ensures that responses are queued in the same order as
// RequestProcessed is called
responseLock sync.Mutex
responseCount uint64
invalidCount uint32
poolEntry *poolEntry
hasBlock func(common.Hash, uint64, bool) bool
responseErrors int
updateCounter uint64
updateTime mclock.AbsTime
frozen uint32 // 1 if client is in frozen state
fcClient *flowcontrol.ClientNode // nil if the peer is server only
fcServer *flowcontrol.ServerNode // nil if the peer is client only
fcParams flowcontrol.ServerParams
fcCosts requestCostTable
trusted, server bool
onlyAnnounce bool
chainSince, chainRecent uint64
stateSince, stateRecent uint64
}
func newPeer(version int, network uint64, trusted bool, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
return &peer{
Peer: p,
rw: rw,
version: version,
network: network,
id: peerIdToString(p.ID()),
trusted: trusted,
errCh: make(chan error, 1),
}
}
// peerIdToString converts enode.ID to a string form
func peerIdToString(id enode.ID) string {
return fmt.Sprintf("%x", id.Bytes())
}
// freeClientId returns a string identifier for the peer. Multiple peers with the
// same identifier can not be connected in free mode simultaneously.
func (p *peer) freeClientId() string {
if addr, ok := p.RemoteAddr().(*net.TCPAddr); ok {
if addr.IP.IsLoopback() {
// using peer id instead of loopback ip address allows multiple free
// connections from local machine to own server
return p.id
} else {
return addr.IP.String()
}
}
return p.id
}
// rejectUpdate returns true if a parameter update has to be rejected because
// the size and/or rate of updates exceed the capacity limitation
func (p *peer) rejectUpdate(size uint64) bool {
now := mclock.Now()
if p.updateCounter == 0 {
p.updateTime = now
} else {
dt := now - p.updateTime
r := uint64(dt / mclock.AbsTime(allowedUpdateRate))
if p.updateCounter > r {
p.updateCounter -= r
p.updateTime += mclock.AbsTime(allowedUpdateRate * time.Duration(r))
} else {
p.updateCounter = 0
p.updateTime = now
}
}
p.updateCounter += size
return p.updateCounter > allowedUpdateBytes
}
// freezeClient temporarily puts the client in a frozen state which means all
// unprocessed and subsequent requests are dropped. Unfreezing happens automatically
// after a short time if the client's buffer value is at least in the slightly positive
// region. The client is also notified about being frozen/unfrozen with a Stop/Resume
// message.
func (p *peer) freezeClient() {
if p.version < lpv3 {
// if Stop/Resume is not supported then just drop the peer after setting
// its frozen status permanently
atomic.StoreUint32(&p.frozen, 1)
p.Peer.Disconnect(p2p.DiscUselessPeer)
return
}
if atomic.SwapUint32(&p.frozen, 1) == 0 {
go func() {
p.SendStop()
time.Sleep(freezeTimeBase + time.Duration(rand.Int63n(int64(freezeTimeRandom))))
for {
bufValue, bufLimit := p.fcClient.BufferStatus()
if bufLimit == 0 {
return
}
if bufValue <= bufLimit/8 {
time.Sleep(freezeCheckPeriod)
} else {
atomic.StoreUint32(&p.frozen, 0)
p.SendResume(bufValue)
break
}
}
}()
}
}
// freezeServer processes Stop/Resume messages from the given server
func (p *peer) freezeServer(frozen bool) {
var f uint32
if frozen {
f = 1
}
if atomic.SwapUint32(&p.frozen, f) != f && frozen {
p.sendQueue.clear()
}
}
// isFrozen returns true if the client is frozen or the server has put our
// client in frozen state
func (p *peer) isFrozen() bool {
return atomic.LoadUint32(&p.frozen) != 0
}
func (p *peer) canQueue() bool {
return p.sendQueue.canQueue() && !p.isFrozen()
}
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 &eth.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)
}
// updateCapacity updates the request serving capacity assigned to a given client
// and also sends an announcement about the updated flow control parameters
func (p *peer) updateCapacity(cap uint64) {
p.responseLock.Lock()
defer p.responseLock.Unlock()
p.fcParams = flowcontrol.ServerParams{MinRecharge: cap, BufLimit: cap * bufLimitRatio}
p.fcClient.UpdateParams(p.fcParams)
var kvList keyValueList
kvList = kvList.add("flowControl/MRR", cap)
kvList = kvList.add("flowControl/BL", cap*bufLimitRatio)
p.queueSend(func() { p.SendAnnounce(announceData{Update: kvList}) })
}
func (p *peer) responseID() uint64 {
p.responseCount += 1
return p.responseCount
}
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})
}
// reply struct represents a reply with the actual data already RLP encoded and
// only the bv (buffer value) missing. This allows the serving mechanism to
// calculate the bv value which depends on the data size before sending the reply.
type reply struct {
w p2p.MsgWriter
msgcode, reqID uint64
data rlp.RawValue
}
// send sends the reply with the calculated buffer value
func (r *reply) send(bv uint64) error {
type resp struct {
ReqID, BV uint64
Data rlp.RawValue
}
return p2p.Send(r.w, r.msgcode, resp{r.reqID, bv, r.data})
}
// size returns the RLP encoded size of the message data
func (r *reply) size() uint32 {
return uint32(len(r.data))
}
func (p *peer) GetRequestCost(msgcode uint64, amount int) uint64 {
p.lock.RLock()
defer p.lock.RUnlock()
costs := p.fcCosts[msgcode]
if costs == nil {
return 0
}
cost := costs.baseCost + costs.reqCost*uint64(amount)
if cost > p.fcParams.BufLimit {
cost = p.fcParams.BufLimit
}
return cost
}
func (p *peer) GetTxRelayCost(amount, size int) uint64 {
p.lock.RLock()
defer p.lock.RUnlock()
costs := p.fcCosts[SendTxV2Msg]
if costs == nil {
return 0
}
cost := costs.baseCost + costs.reqCost*uint64(amount)
sizeCost := costs.baseCost + costs.reqCost*uint64(size)/txSizeCostLimit
if sizeCost > cost {
cost = sizeCost
}
if cost > p.fcParams.BufLimit {
cost = p.fcParams.BufLimit
}
return cost
}
// HasBlock checks if the peer has a given block
func (p *peer) HasBlock(hash common.Hash, number uint64, hasState bool) bool {
var head, since, recent uint64
p.lock.RLock()
if p.headInfo != nil {
head = p.headInfo.Number
}
if hasState {
since = p.stateSince
recent = p.stateRecent
} else {
since = p.chainSince
recent = p.chainRecent
}
hasBlock := p.hasBlock
p.lock.RUnlock()
return head >= number && number >= since && (recent == 0 || number+recent+4 > head) && hasBlock != nil && hasBlock(hash, number, hasState)
}
// 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)
}
// SendStop notifies the client about being in frozen state
func (p *peer) SendStop() error {
return p2p.Send(p.rw, StopMsg, struct{}{})
}
// SendResume notifies the client about getting out of frozen state
func (p *peer) SendResume(bv uint64) error {
return p2p.Send(p.rw, ResumeMsg, bv)
}
// ReplyBlockHeaders creates a reply with a batch of block headers
func (p *peer) ReplyBlockHeaders(reqID uint64, headers []*types.Header) *reply {
data, _ := rlp.EncodeToBytes(headers)
return &reply{p.rw, BlockHeadersMsg, reqID, data}
}
// ReplyBlockBodiesRLP creates a reply with a batch of block contents from
// an already RLP encoded format.
func (p *peer) ReplyBlockBodiesRLP(reqID uint64, bodies []rlp.RawValue) *reply {
data, _ := rlp.EncodeToBytes(bodies)
return &reply{p.rw, BlockBodiesMsg, reqID, data}
}
// ReplyCode creates a reply with a batch of arbitrary internal data, corresponding to the
// hashes requested.
func (p *peer) ReplyCode(reqID uint64, codes [][]byte) *reply {
data, _ := rlp.EncodeToBytes(codes)
return &reply{p.rw, CodeMsg, reqID, data}
}
// ReplyReceiptsRLP creates a reply with a batch of transaction receipts, corresponding to the
// ones requested from an already RLP encoded format.
func (p *peer) ReplyReceiptsRLP(reqID uint64, receipts []rlp.RawValue) *reply {
data, _ := rlp.EncodeToBytes(receipts)
return &reply{p.rw, ReceiptsMsg, reqID, data}
}
// ReplyProofsV2 creates a reply with a batch of merkle proofs, corresponding to the ones requested.
func (p *peer) ReplyProofsV2(reqID uint64, proofs light.NodeList) *reply {
data, _ := rlp.EncodeToBytes(proofs)
return &reply{p.rw, ProofsV2Msg, reqID, data}
}
// ReplyHelperTrieProofs creates a reply with a batch of HelperTrie proofs, corresponding to the ones requested.
func (p *peer) ReplyHelperTrieProofs(reqID uint64, resp HelperTrieResps) *reply {
data, _ := rlp.EncodeToBytes(resp)
return &reply{p.rw, HelperTrieProofsMsg, reqID, data}
}
// ReplyTxStatus creates a reply with a batch of transaction status records, corresponding to the ones requested.
func (p *peer) ReplyTxStatus(reqID uint64, stats []light.TxStatus) *reply {
data, _ := rlp.EncodeToBytes(stats)
return &reply{p.rw, TxStatusMsg, reqID, data}
}
// 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, GetProofsV2Msg, reqID, cost, reqs)
}
// RequestHelperTrieProofs fetches a batch of HelperTrie merkle proofs from a remote node.
func (p *peer) RequestHelperTrieProofs(reqID, cost uint64, reqs []HelperTrieReq) error {
p.Log().Debug("Fetching batch of HelperTrie proofs", "count", len(reqs))
return sendRequest(p.rw, GetHelperTrieProofsMsg, reqID, cost, reqs)
}
// RequestTxStatus fetches a batch of transaction status records from a remote node.
func (p *peer) RequestTxStatus(reqID, cost uint64, txHashes []common.Hash) error {
p.Log().Debug("Requesting transaction status", "count", len(txHashes))
return sendRequest(p.rw, GetTxStatusMsg, reqID, cost, txHashes)
}
// SendTxStatus creates a reply with a batch of transactions to be added to the remote transaction pool.
func (p *peer) SendTxs(reqID, cost uint64, txs rlp.RawValue) error {
p.Log().Debug("Sending batch of transactions", "size", len(txs))
return sendRequest(p.rw, SendTxV2Msg, reqID, cost, 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, uint64) {
m := make(keyValueMap)
var size uint64
for _, entry := range l {
m[entry.Key] = entry.Value
size += uint64(len(entry.Key)) + uint64(len(entry.Value)) + 8
}
return m, size
}
func (m keyValueMap) get(key string, val interface{}) error {
enc, ok := m[key]
if !ok {
return errResp(ErrMissingKey, "%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
// Add some basic handshake fields
send = send.add("protocolVersion", uint64(p.version))
send = send.add("networkId", 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 {
// Add some information which services server can offer.
if !server.config.UltraLightOnlyAnnounce {
send = send.add("serveHeaders", nil)
send = send.add("serveChainSince", uint64(0))
send = send.add("serveStateSince", uint64(0))
// If local ethereum node is running in archive mode, advertise ourselves we have
// all version state data. Otherwise only recent state is available.
stateRecent := uint64(core.TriesInMemory - 4)
if server.archiveMode {
stateRecent = 0
}
send = send.add("serveRecentState", stateRecent)
send = send.add("txRelay", nil)
}
send = send.add("flowControl/BL", server.defParams.BufLimit)
send = send.add("flowControl/MRR", server.defParams.MinRecharge)
var costList RequestCostList
if server.costTracker.testCostList != nil {
costList = server.costTracker.testCostList
} else {
costList = server.costTracker.makeCostList(server.costTracker.globalFactor())
}
send = send.add("flowControl/MRC", costList)
p.fcCosts = costList.decode(ProtocolLengths[uint(p.version)])
p.fcParams = server.defParams
// Add advertised checkpoint and register block height which
// client can verify the checkpoint validity.
if server.oracle != nil && server.oracle.isRunning() {
cp, height := server.oracle.stableCheckpoint()
if cp != nil {
send = send.add("checkpoint/value", cp)
send = send.add("checkpoint/registerHeight", height)
}
}
} else {
// Add some client-specific handshake fields
p.announceType = announceTypeSimple
if p.trusted {
p.announceType = announceTypeSigned
}
send = send.add("announceType", p.announceType)
}
recvList, err := p.sendReceiveHandshake(send)
if err != nil {
return err
}
recv, size := recvList.decode()
if p.rejectUpdate(size) {
return errResp(ErrRequestRejected, "")
}
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 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 {
p.server = recv.get("flowControl/MRR", nil) == nil
if p.server {
p.announceType = announceTypeNone // connected to another server, send no messages
} else {
if recv.get("announceType", &p.announceType) != nil {
// set default announceType on server side
p.announceType = announceTypeSimple
}
p.fcClient = flowcontrol.NewClientNode(server.fcManager, server.defParams)
}
} else {
if recv.get("serveChainSince", &p.chainSince) != nil {
p.onlyAnnounce = true
}
if recv.get("serveRecentChain", &p.chainRecent) != nil {
p.chainRecent = 0
}
if recv.get("serveStateSince", &p.stateSince) != nil {
p.onlyAnnounce = true
}
if recv.get("serveRecentState", &p.stateRecent) != nil {
p.stateRecent = 0
}
if recv.get("txRelay", nil) != nil {
p.onlyAnnounce = true
}
if p.onlyAnnounce && !p.trusted {
return errResp(ErrUselessPeer, "peer cannot serve requests")
}
var sParams flowcontrol.ServerParams
if err := recv.get("flowControl/BL", &sParams.BufLimit); err != nil {
return err
}
if err := recv.get("flowControl/MRR", &sParams.MinRecharge); err != nil {
return err
}
var MRC RequestCostList
if err := recv.get("flowControl/MRC", &MRC); err != nil {
return err
}
p.fcParams = sParams
p.fcServer = flowcontrol.NewServerNode(sParams, &mclock.System{})
p.fcCosts = MRC.decode(ProtocolLengths[uint(p.version)])
recv.get("checkpoint/value", &p.checkpoint)
recv.get("checkpoint/registerHeight", &p.checkpointNumber)
if !p.onlyAnnounce {
for msgCode := range reqAvgTimeCost {
if p.fcCosts[msgCode] == nil {
return errResp(ErrUselessPeer, "peer does not support message %d", msgCode)
}
}
}
p.server = true
}
p.headInfo = &announceData{Td: rTd, Hash: rHash, Number: rNum}
return nil
}
// updateFlowControl updates the flow control parameters belonging to the server
// node if the announced key/value set contains relevant fields
func (p *peer) updateFlowControl(update keyValueMap) {
if p.fcServer == nil {
return
}
// If any of the flow control params is nil, refuse to update.
var params flowcontrol.ServerParams
if update.get("flowControl/BL", &params.BufLimit) == nil && update.get("flowControl/MRR", &params.MinRecharge) == nil {
// todo can light client set a minimal acceptable flow control params?
p.fcParams = params
p.fcServer.UpdateParams(params)
}
var MRC RequestCostList
if update.get("flowControl/MRC", &MRC) == nil {
costUpdate := MRC.decode(ProtocolLengths[uint(p.version)])
for code, cost := range costUpdate {
p.fcCosts[code] = cost
}
}
}
// String implements fmt.Stringer.
func (p *peer) String() string {
return fmt.Sprintf("Peer %s [%s]", p.id,
fmt.Sprintf("les/%d", p.version),
)
}
// peerSetNotify is a callback interface to notify services about added or
// removed peers
type peerSetNotify interface {
registerPeer(*peer)
unregisterPeer(*peer)
}
// 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
notifyList []peerSetNotify
closed bool
}
// newPeerSet creates a new peer set to track the active participants.
func newPeerSet() *peerSet {
return &peerSet{
peers: make(map[string]*peer),
}
}
// notify adds a service to be notified about added or removed peers
func (ps *peerSet) notify(n peerSetNotify) {
ps.lock.Lock()
ps.notifyList = append(ps.notifyList, n)
peers := make([]*peer, 0, len(ps.peers))
for _, p := range ps.peers {
peers = append(peers, p)
}
ps.lock.Unlock()
for _, p := range peers {
n.registerPeer(p)
}
}
// 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()
if ps.closed {
ps.lock.Unlock()
return errClosed
}
if _, ok := ps.peers[p.id]; ok {
ps.lock.Unlock()
return errAlreadyRegistered
}
ps.peers[p.id] = p
p.sendQueue = newExecQueue(100)
peers := make([]peerSetNotify, len(ps.notifyList))
copy(peers, ps.notifyList)
ps.lock.Unlock()
for _, n := range peers {
n.registerPeer(p)
}
return nil
}
// Unregister removes a remote peer from the active set, disabling any further
// actions to/from that particular entity. It also initiates disconnection at the networking layer.
func (ps *peerSet) Unregister(id string) error {
ps.lock.Lock()
if p, ok := ps.peers[id]; !ok {
ps.lock.Unlock()
return errNotRegistered
} else {
delete(ps.peers, id)
peers := make([]peerSetNotify, len(ps.notifyList))
copy(peers, ps.notifyList)
ps.lock.Unlock()
for _, n := range peers {
n.unregisterPeer(p)
}
p.sendQueue.quit()
p.Peer.Disconnect(p2p.DiscUselessPeer)
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
}