// Copyright 2015 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 . package eth import ( "encoding/json" "errors" "fmt" "math" "math/big" "sync" "sync/atomic" "time" "github.com/ethereum/go-ethereum/common" "github.com/ethereum/go-ethereum/consensus" "github.com/ethereum/go-ethereum/consensus/misc" "github.com/ethereum/go-ethereum/core" "github.com/ethereum/go-ethereum/core/types" "github.com/ethereum/go-ethereum/eth/downloader" "github.com/ethereum/go-ethereum/eth/fetcher" "github.com/ethereum/go-ethereum/ethdb" "github.com/ethereum/go-ethereum/event" "github.com/ethereum/go-ethereum/log" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/p2p/discover" "github.com/ethereum/go-ethereum/params" "github.com/ethereum/go-ethereum/rlp" ) const ( softResponseLimit = 2 * 1024 * 1024 // Target maximum size of returned blocks, headers or node data. estHeaderRlpSize = 500 // Approximate size of an RLP encoded block header // txChanSize is the size of channel listening to TxsPreEvent. // The number is referenced from the size of tx pool. txChanSize = 4096 ) var ( daoChallengeTimeout = 15 * time.Second // Time allowance for a node to reply to the DAO handshake challenge ) // errIncompatibleConfig is returned if the requested protocols and configs are // not compatible (low protocol version restrictions and high requirements). var errIncompatibleConfig = errors.New("incompatible configuration") func errResp(code errCode, format string, v ...interface{}) error { return fmt.Errorf("%v - %v", code, fmt.Sprintf(format, v...)) } type ProtocolManager struct { networkId uint64 fastSync uint32 // Flag whether fast sync is enabled (gets disabled if we already have blocks) acceptTxs uint32 // Flag whether we're considered synchronised (enables transaction processing) txpool txPool blockchain *core.BlockChain chainconfig *params.ChainConfig maxPeers int downloader *downloader.Downloader fetcher *fetcher.Fetcher peers *peerSet SubProtocols []p2p.Protocol eventMux *event.TypeMux txsCh chan core.TxsPreEvent txsSub event.Subscription minedBlockSub *event.TypeMuxSubscription // channels for fetcher, syncer, txsyncLoop newPeerCh chan *peer txsyncCh chan *txsync quitSync chan struct{} noMorePeers chan struct{} // wait group is used for graceful shutdowns during downloading // and processing wg sync.WaitGroup } // NewProtocolManager returns a new Ethereum sub protocol manager. The Ethereum sub protocol manages peers capable // with the Ethereum network. func NewProtocolManager(config *params.ChainConfig, mode downloader.SyncMode, networkId uint64, mux *event.TypeMux, txpool txPool, engine consensus.Engine, blockchain *core.BlockChain, chaindb ethdb.Database) (*ProtocolManager, error) { // Create the protocol manager with the base fields manager := &ProtocolManager{ networkId: networkId, eventMux: mux, txpool: txpool, blockchain: blockchain, chainconfig: config, peers: newPeerSet(), newPeerCh: make(chan *peer), noMorePeers: make(chan struct{}), txsyncCh: make(chan *txsync), quitSync: make(chan struct{}), } // Figure out whether to allow fast sync or not if mode == downloader.FastSync && blockchain.CurrentBlock().NumberU64() > 0 { log.Warn("Blockchain not empty, fast sync disabled") mode = downloader.FullSync } if mode == downloader.FastSync { manager.fastSync = uint32(1) } // Initiate a sub-protocol for every implemented version we can handle manager.SubProtocols = make([]p2p.Protocol, 0, len(ProtocolVersions)) for i, version := range ProtocolVersions { // Skip protocol version if incompatible with the mode of operation if mode == downloader.FastSync && version < eth63 { continue } // Compatible; initialise the sub-protocol version := version // Closure for the run manager.SubProtocols = append(manager.SubProtocols, p2p.Protocol{ Name: ProtocolName, Version: version, Length: ProtocolLengths[i], Run: func(p *p2p.Peer, rw p2p.MsgReadWriter) error { peer := manager.newPeer(int(version), p, rw) select { case manager.newPeerCh <- peer: manager.wg.Add(1) defer manager.wg.Done() return manager.handle(peer) case <-manager.quitSync: return p2p.DiscQuitting } }, NodeInfo: func() interface{} { return manager.NodeInfo() }, PeerInfo: func(id discover.NodeID) interface{} { if p := manager.peers.Peer(fmt.Sprintf("%x", id[:8])); p != nil { return p.Info() } return nil }, }) } if len(manager.SubProtocols) == 0 { return nil, errIncompatibleConfig } // Construct the different synchronisation mechanisms manager.downloader = downloader.New(mode, chaindb, manager.eventMux, blockchain, nil, manager.removePeer) validator := func(header *types.Header) error { return engine.VerifyHeader(blockchain, header, true) } heighter := func() uint64 { return blockchain.CurrentBlock().NumberU64() } inserter := func(blocks types.Blocks) (int, error) { // If fast sync is running, deny importing weird blocks if atomic.LoadUint32(&manager.fastSync) == 1 { log.Warn("Discarded bad propagated block", "number", blocks[0].Number(), "hash", blocks[0].Hash()) return 0, nil } atomic.StoreUint32(&manager.acceptTxs, 1) // Mark initial sync done on any fetcher import return manager.blockchain.InsertChain(blocks) } manager.fetcher = fetcher.New(blockchain.GetBlockByHash, validator, manager.BroadcastBlock, heighter, inserter, manager.removePeer) return manager, nil } func (pm *ProtocolManager) removePeer(id string) { // Short circuit if the peer was already removed peer := pm.peers.Peer(id) if peer == nil { return } log.Debug("Removing Ethereum peer", "peer", id) // Unregister the peer from the downloader and Ethereum peer set pm.downloader.UnregisterPeer(id) if err := pm.peers.Unregister(id); err != nil { log.Error("Peer removal failed", "peer", id, "err", err) } // Hard disconnect at the networking layer if peer != nil { peer.Peer.Disconnect(p2p.DiscUselessPeer) } } func (pm *ProtocolManager) Start(maxPeers int) { pm.maxPeers = maxPeers // broadcast transactions pm.txsCh = make(chan core.TxsPreEvent, txChanSize) pm.txsSub = pm.txpool.SubscribeTxPreEvent(pm.txsCh) go pm.txBroadcastLoop() // broadcast mined blocks pm.minedBlockSub = pm.eventMux.Subscribe(core.NewMinedBlockEvent{}) go pm.minedBroadcastLoop() // start sync handlers go pm.syncer() go pm.txsyncLoop() } func (pm *ProtocolManager) Stop() { log.Info("Stopping Ethereum protocol") pm.txsSub.Unsubscribe() // quits txBroadcastLoop pm.minedBlockSub.Unsubscribe() // quits blockBroadcastLoop // Quit the sync loop. // After this send has completed, no new peers will be accepted. pm.noMorePeers <- struct{}{} // Quit fetcher, txsyncLoop. close(pm.quitSync) // Disconnect existing sessions. // This also closes the gate for any new registrations on the peer set. // sessions which are already established but not added to pm.peers yet // will exit when they try to register. pm.peers.Close() // Wait for all peer handler goroutines and the loops to come down. pm.wg.Wait() log.Info("Ethereum protocol stopped") } func (pm *ProtocolManager) newPeer(pv int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer { return newPeer(pv, p, newMeteredMsgWriter(rw)) } // handle is the callback invoked to manage the life cycle of an eth peer. When // this function terminates, the peer is disconnected. func (pm *ProtocolManager) handle(p *peer) error { // Ignore maxPeers if this is a trusted peer if pm.peers.Len() >= pm.maxPeers && !p.Peer.Info().Network.Trusted { return p2p.DiscTooManyPeers } p.Log().Debug("Ethereum peer connected", "name", p.Name()) // Execute the Ethereum handshake var ( genesis = pm.blockchain.Genesis() head = pm.blockchain.CurrentHeader() hash = head.Hash() number = head.Number.Uint64() td = pm.blockchain.GetTd(hash, number) ) if err := p.Handshake(pm.networkId, td, hash, genesis.Hash()); err != nil { p.Log().Debug("Ethereum handshake failed", "err", err) return err } if rw, ok := p.rw.(*meteredMsgReadWriter); ok { rw.Init(p.version) } // Register the peer locally if err := pm.peers.Register(p); err != nil { p.Log().Error("Ethereum peer registration failed", "err", err) return err } defer pm.removePeer(p.id) // Register the peer in the downloader. If the downloader considers it banned, we disconnect if err := pm.downloader.RegisterPeer(p.id, p.version, p); err != nil { return err } // Propagate existing transactions. new transactions appearing // after this will be sent via broadcasts. pm.syncTransactions(p) // If we're DAO hard-fork aware, validate any remote peer with regard to the hard-fork if daoBlock := pm.chainconfig.DAOForkBlock; daoBlock != nil { // Request the peer's DAO fork header for extra-data validation if err := p.RequestHeadersByNumber(daoBlock.Uint64(), 1, 0, false); err != nil { return err } // Start a timer to disconnect if the peer doesn't reply in time p.forkDrop = time.AfterFunc(daoChallengeTimeout, func() { p.Log().Debug("Timed out DAO fork-check, dropping") pm.removePeer(p.id) }) // Make sure it's cleaned up if the peer dies off defer func() { if p.forkDrop != nil { p.forkDrop.Stop() p.forkDrop = nil } }() } // main loop. handle incoming messages. for { if err := pm.handleMsg(p); err != nil { p.Log().Debug("Ethereum message handling failed", "err", err) return err } } } // handleMsg is invoked whenever an inbound message is received from a remote // peer. The remote connection is torn down upon returning any error. func (pm *ProtocolManager) handleMsg(p *peer) error { // Read the next message from the remote peer, and ensure it's fully consumed msg, err := p.rw.ReadMsg() if err != nil { return err } if msg.Size > ProtocolMaxMsgSize { return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize) } defer msg.Discard() // Handle the message depending on its contents switch { case msg.Code == StatusMsg: // Status messages should never arrive after the handshake return errResp(ErrExtraStatusMsg, "uncontrolled status message") // Block header query, collect the requested headers and reply case msg.Code == GetBlockHeadersMsg: // Decode the complex header query var query getBlockHeadersData if err := msg.Decode(&query); err != nil { return errResp(ErrDecode, "%v: %v", msg, err) } hashMode := query.Origin.Hash != (common.Hash{}) // Gather headers until the fetch or network limits is reached var ( bytes common.StorageSize headers []*types.Header unknown bool ) for !unknown && len(headers) < int(query.Amount) && bytes < softResponseLimit && len(headers) < downloader.MaxHeaderFetch { // Retrieve the next header satisfying the query var origin *types.Header if hashMode { origin = pm.blockchain.GetHeaderByHash(query.Origin.Hash) } else { origin = pm.blockchain.GetHeaderByNumber(query.Origin.Number) } if origin == nil { break } number := origin.Number.Uint64() headers = append(headers, origin) bytes += estHeaderRlpSize // Advance to the next header of the query switch { case query.Origin.Hash != (common.Hash{}) && query.Reverse: // Hash based traversal towards the genesis block for i := 0; i < int(query.Skip)+1; i++ { if header := pm.blockchain.GetHeader(query.Origin.Hash, number); header != nil { query.Origin.Hash = header.ParentHash number-- } else { unknown = true break } } case query.Origin.Hash != (common.Hash{}) && !query.Reverse: // Hash based traversal towards the leaf block var ( current = origin.Number.Uint64() next = current + query.Skip + 1 ) if next <= current { infos, _ := json.MarshalIndent(p.Peer.Info(), "", " ") p.Log().Warn("GetBlockHeaders skip overflow attack", "current", current, "skip", query.Skip, "next", next, "attacker", infos) unknown = true } else { if header := pm.blockchain.GetHeaderByNumber(next); header != nil { if pm.blockchain.GetBlockHashesFromHash(header.Hash(), query.Skip+1)[query.Skip] == query.Origin.Hash { query.Origin.Hash = header.Hash() } else { unknown = true } } else { unknown = true } } case query.Reverse: // Number based traversal towards the genesis block if query.Origin.Number >= query.Skip+1 { query.Origin.Number -= query.Skip + 1 } else { unknown = true } case !query.Reverse: // Number based traversal towards the leaf block query.Origin.Number += query.Skip + 1 } } return p.SendBlockHeaders(headers) case msg.Code == BlockHeadersMsg: // A batch of headers arrived to one of our previous requests var headers []*types.Header if err := msg.Decode(&headers); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // If no headers were received, but we're expending a DAO fork check, maybe it's that if len(headers) == 0 && p.forkDrop != nil { // Possibly an empty reply to the fork header checks, sanity check TDs verifyDAO := true // If we already have a DAO header, we can check the peer's TD against it. If // the peer's ahead of this, it too must have a reply to the DAO check if daoHeader := pm.blockchain.GetHeaderByNumber(pm.chainconfig.DAOForkBlock.Uint64()); daoHeader != nil { if _, td := p.Head(); td.Cmp(pm.blockchain.GetTd(daoHeader.Hash(), daoHeader.Number.Uint64())) >= 0 { verifyDAO = false } } // If we're seemingly on the same chain, disable the drop timer if verifyDAO { p.Log().Debug("Seems to be on the same side of the DAO fork") p.forkDrop.Stop() p.forkDrop = nil return nil } } // Filter out any explicitly requested headers, deliver the rest to the downloader filter := len(headers) == 1 if filter { // If it's a potential DAO fork check, validate against the rules if p.forkDrop != nil && pm.chainconfig.DAOForkBlock.Cmp(headers[0].Number) == 0 { // Disable the fork drop timer p.forkDrop.Stop() p.forkDrop = nil // Validate the header and either drop the peer or continue if err := misc.VerifyDAOHeaderExtraData(pm.chainconfig, headers[0]); err != nil { p.Log().Debug("Verified to be on the other side of the DAO fork, dropping") return err } p.Log().Debug("Verified to be on the same side of the DAO fork") return nil } // Irrelevant of the fork checks, send the header to the fetcher just in case headers = pm.fetcher.FilterHeaders(p.id, headers, time.Now()) } if len(headers) > 0 || !filter { err := pm.downloader.DeliverHeaders(p.id, headers) if err != nil { log.Debug("Failed to deliver headers", "err", err) } } case msg.Code == GetBlockBodiesMsg: // Decode the retrieval message msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) if _, err := msgStream.List(); err != nil { return err } // Gather blocks until the fetch or network limits is reached var ( hash common.Hash bytes int bodies []rlp.RawValue ) for bytes < softResponseLimit && len(bodies) < downloader.MaxBlockFetch { // Retrieve the hash of the next block if err := msgStream.Decode(&hash); err == rlp.EOL { break } else if err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Retrieve the requested block body, stopping if enough was found if data := pm.blockchain.GetBodyRLP(hash); len(data) != 0 { bodies = append(bodies, data) bytes += len(data) } } return p.SendBlockBodiesRLP(bodies) case msg.Code == BlockBodiesMsg: // A batch of block bodies arrived to one of our previous requests var request blockBodiesData if err := msg.Decode(&request); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Deliver them all to the downloader for queuing transactions := make([][]*types.Transaction, len(request)) uncles := make([][]*types.Header, len(request)) for i, body := range request { transactions[i] = body.Transactions uncles[i] = body.Uncles } // Filter out any explicitly requested bodies, deliver the rest to the downloader filter := len(transactions) > 0 || len(uncles) > 0 if filter { transactions, uncles = pm.fetcher.FilterBodies(p.id, transactions, uncles, time.Now()) } if len(transactions) > 0 || len(uncles) > 0 || !filter { err := pm.downloader.DeliverBodies(p.id, transactions, uncles) if err != nil { log.Debug("Failed to deliver bodies", "err", err) } } case p.version >= eth63 && msg.Code == GetNodeDataMsg: // Decode the retrieval message msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) if _, err := msgStream.List(); err != nil { return err } // Gather state data until the fetch or network limits is reached var ( hash common.Hash bytes int data [][]byte ) for bytes < softResponseLimit && len(data) < downloader.MaxStateFetch { // Retrieve the hash of the next state entry if err := msgStream.Decode(&hash); err == rlp.EOL { break } else if err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Retrieve the requested state entry, stopping if enough was found if entry, err := pm.blockchain.TrieNode(hash); err == nil { data = append(data, entry) bytes += len(entry) } } return p.SendNodeData(data) case p.version >= eth63 && msg.Code == NodeDataMsg: // A batch of node state data arrived to one of our previous requests var data [][]byte if err := msg.Decode(&data); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Deliver all to the downloader if err := pm.downloader.DeliverNodeData(p.id, data); err != nil { log.Debug("Failed to deliver node state data", "err", err) } case p.version >= eth63 && msg.Code == GetReceiptsMsg: // Decode the retrieval message msgStream := rlp.NewStream(msg.Payload, uint64(msg.Size)) if _, err := msgStream.List(); err != nil { return err } // Gather state data until the fetch or network limits is reached var ( hash common.Hash bytes int receipts []rlp.RawValue ) for bytes < softResponseLimit && len(receipts) < downloader.MaxReceiptFetch { // Retrieve the hash of the next block if err := msgStream.Decode(&hash); err == rlp.EOL { break } else if err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Retrieve the requested block's receipts, skipping if unknown to us results := pm.blockchain.GetReceiptsByHash(hash) if results == nil { if header := pm.blockchain.GetHeaderByHash(hash); header == nil || header.ReceiptHash != types.EmptyRootHash { continue } } // If known, encode and queue for response packet if encoded, err := rlp.EncodeToBytes(results); err != nil { log.Error("Failed to encode receipt", "err", err) } else { receipts = append(receipts, encoded) bytes += len(encoded) } } return p.SendReceiptsRLP(receipts) case p.version >= eth63 && msg.Code == ReceiptsMsg: // A batch of receipts arrived to one of our previous requests var receipts [][]*types.Receipt if err := msg.Decode(&receipts); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } // Deliver all to the downloader if err := pm.downloader.DeliverReceipts(p.id, receipts); err != nil { log.Debug("Failed to deliver receipts", "err", err) } case msg.Code == NewBlockHashesMsg: var announces newBlockHashesData if err := msg.Decode(&announces); err != nil { return errResp(ErrDecode, "%v: %v", msg, err) } // Mark the hashes as present at the remote node for _, block := range announces { p.MarkBlock(block.Hash) } // Schedule all the unknown hashes for retrieval unknown := make(newBlockHashesData, 0, len(announces)) for _, block := range announces { if !pm.blockchain.HasBlock(block.Hash, block.Number) { unknown = append(unknown, block) } } for _, block := range unknown { pm.fetcher.Notify(p.id, block.Hash, block.Number, time.Now(), p.RequestOneHeader, p.RequestBodies) } case msg.Code == NewBlockMsg: // Retrieve and decode the propagated block var request newBlockData if err := msg.Decode(&request); err != nil { return errResp(ErrDecode, "%v: %v", msg, err) } request.Block.ReceivedAt = msg.ReceivedAt request.Block.ReceivedFrom = p // Mark the peer as owning the block and schedule it for import p.MarkBlock(request.Block.Hash()) pm.fetcher.Enqueue(p.id, request.Block) // Assuming the block is importable by the peer, but possibly not yet done so, // calculate the head hash and TD that the peer truly must have. var ( trueHead = request.Block.ParentHash() trueTD = new(big.Int).Sub(request.TD, request.Block.Difficulty()) ) // Update the peers total difficulty if better than the previous if _, td := p.Head(); trueTD.Cmp(td) > 0 { p.SetHead(trueHead, trueTD) // Schedule a sync if above ours. Note, this will not fire a sync for a gap of // a singe block (as the true TD is below the propagated block), however this // scenario should easily be covered by the fetcher. currentBlock := pm.blockchain.CurrentBlock() if trueTD.Cmp(pm.blockchain.GetTd(currentBlock.Hash(), currentBlock.NumberU64())) > 0 { go pm.synchronise(p) } } case msg.Code == TxMsg: // Transactions arrived, make sure we have a valid and fresh chain to handle them if atomic.LoadUint32(&pm.acceptTxs) == 0 { break } // Transactions can be processed, parse all of them and deliver to the pool var txs []*types.Transaction if err := msg.Decode(&txs); err != nil { return errResp(ErrDecode, "msg %v: %v", msg, err) } for i, tx := range txs { // Validate and mark the remote transaction if tx == nil { return errResp(ErrDecode, "transaction %d is nil", i) } p.MarkTransaction(tx.Hash()) } pm.txpool.AddRemotes(txs) default: return errResp(ErrInvalidMsgCode, "%v", msg.Code) } return nil } // BroadcastBlock will either propagate a block to a subset of it's peers, or // will only announce it's availability (depending what's requested). func (pm *ProtocolManager) BroadcastBlock(block *types.Block, propagate bool) { hash := block.Hash() peers := pm.peers.PeersWithoutBlock(hash) // If propagation is requested, send to a subset of the peer if propagate { // Calculate the TD of the block (it's not imported yet, so block.Td is not valid) var td *big.Int if parent := pm.blockchain.GetBlock(block.ParentHash(), block.NumberU64()-1); parent != nil { td = new(big.Int).Add(block.Difficulty(), pm.blockchain.GetTd(block.ParentHash(), block.NumberU64()-1)) } else { log.Error("Propagating dangling block", "number", block.Number(), "hash", hash) return } // Send the block to a subset of our peers transfer := peers[:int(math.Sqrt(float64(len(peers))))] for _, peer := range transfer { peer.SendNewBlock(block, td) } log.Trace("Propagated block", "hash", hash, "recipients", len(transfer), "duration", common.PrettyDuration(time.Since(block.ReceivedAt))) return } // Otherwise if the block is indeed in out own chain, announce it if pm.blockchain.HasBlock(hash, block.NumberU64()) { for _, peer := range peers { peer.SendNewBlockHashes([]common.Hash{hash}, []uint64{block.NumberU64()}) } log.Trace("Announced block", "hash", hash, "recipients", len(peers), "duration", common.PrettyDuration(time.Since(block.ReceivedAt))) } } // BroadcastTxs will propagate a batch of transactions to all peers which are not known to // already have the given transaction. func (pm *ProtocolManager) BroadcastTxs(txs types.Transactions) { var txset = make(map[*peer]types.Transactions) // Broadcast transactions to a batch of peers not knowing about it for _, tx := range txs { peers := pm.peers.PeersWithoutTx(tx.Hash()) for _, peer := range peers { txset[peer] = append(txset[peer], tx) } log.Trace("Broadcast transaction", "hash", tx.Hash(), "recipients", len(peers)) } // FIXME include this again: peers = peers[:int(math.Sqrt(float64(len(peers))))] for peer, txs := range txset { peer.SendTransactions(txs) } } // Mined broadcast loop func (pm *ProtocolManager) minedBroadcastLoop() { // automatically stops if unsubscribe for obj := range pm.minedBlockSub.Chan() { switch ev := obj.Data.(type) { case core.NewMinedBlockEvent: pm.BroadcastBlock(ev.Block, true) // First propagate block to peers pm.BroadcastBlock(ev.Block, false) // Only then announce to the rest } } } func (pm *ProtocolManager) txBroadcastLoop() { for { select { case event := <-pm.txsCh: pm.BroadcastTxs(event.Txs) // Err() channel will be closed when unsubscribing. case <-pm.txsSub.Err(): return } } } // NodeInfo represents a short summary of the Ethereum sub-protocol metadata // known about the host peer. type NodeInfo struct { Network uint64 `json:"network"` // Ethereum network ID (1=Frontier, 2=Morden, Ropsten=3, Rinkeby=4) Difficulty *big.Int `json:"difficulty"` // Total difficulty of the host's blockchain Genesis common.Hash `json:"genesis"` // SHA3 hash of the host's genesis block Config *params.ChainConfig `json:"config"` // Chain configuration for the fork rules Head common.Hash `json:"head"` // SHA3 hash of the host's best owned block } // NodeInfo retrieves some protocol metadata about the running host node. func (pm *ProtocolManager) NodeInfo() *NodeInfo { currentBlock := pm.blockchain.CurrentBlock() return &NodeInfo{ Network: pm.networkId, Difficulty: pm.blockchain.GetTd(currentBlock.Hash(), currentBlock.NumberU64()), Genesis: pm.blockchain.Genesis().Hash(), Config: pm.blockchain.Config(), Head: currentBlock.Hash(), } }