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path: root/eth/handler.go
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package eth

import (
    "fmt"
    "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"
    "github.com/ethereum/go-ethereum/rlp"
)

func errResp(code errCode, format string, v ...interface{}) error {
    return fmt.Errorf("%v - %v", code, fmt.Sprintf(format, v...))
}

// main entrypoint, wrappers starting a server running the eth protocol
// use this constructor to attach the protocol ("class") to server caps
// the Dev p2p layer then runs the protocol instance on each peer
func EthProtocol(protocolVersion, networkId int, txPool txPool, chainManager chainManager, downloader *downloader.Downloader) p2p.Protocol {
    protocol := newProtocolManager(txPool, chainManager, downloader)

    return p2p.Protocol{
        Name:    "eth",
        Version: uint(protocolVersion),
        Length:  ProtocolLength,
        Run: func(p *p2p.Peer, rw p2p.MsgReadWriter) error {
            //return runEthProtocol(protocolVersion, networkId, txPool, chainManager, downloader, p, rw)
            peer := protocol.newPeer(protocolVersion, networkId, p, rw)
            err := protocol.handle(peer)
            glog.V(logger.Detail).Infof("[%s]: %v\n", peer.id, err)

            return err
        },
    }
}

type hashFetcherFn func(common.Hash) error
type blockFetcherFn func([]common.Hash) error

// extProt is an interface which is passed around so we can expose GetHashes and GetBlock without exposing it to the rest of the protocol
// extProt is passed around to peers which require to GetHashes and GetBlocks
type extProt struct {
    getHashes hashFetcherFn
    getBlocks blockFetcherFn
}

func (ep extProt) GetHashes(hash common.Hash) error    { return ep.getHashes(hash) }
func (ep extProt) GetBlock(hashes []common.Hash) error { return ep.getBlocks(hashes) }

type EthProtocolManager struct {
    protVer, netId int
    txpool         txPool
    chainman       chainManager
    downloader     *downloader.Downloader

    pmu   sync.Mutex
    peers map[string]*peer
}

func newProtocolManager(txpool txPool, chainman chainManager, downloader *downloader.Downloader) *EthProtocolManager {
    return &EthProtocolManager{
        txpool:     txpool,
        chainman:   chainman,
        downloader: downloader,
        peers:      make(map[string]*peer),
    }
}

func (pm *EthProtocolManager) newPeer(pv, nv int, p *p2p.Peer, rw p2p.MsgReadWriter) *peer {
    pm.pmu.Lock()
    defer pm.pmu.Unlock()

    td, current, genesis := pm.chainman.Status()

    peer := newPeer(pv, nv, genesis, current, td, p, rw)
    pm.peers[peer.id] = peer

    return peer
}

func (pm *EthProtocolManager) handle(p *peer) error {
    if err := p.handleStatus(); err != nil {
        return err
    }

    pm.downloader.RegisterPeer(p.id, p.td, p.currentHash, p.requestHashes, p.requestBlocks)
    defer pm.downloader.UnregisterPeer(p.id)

    // propagate existing transactions. new transactions appearing
    // after this will be sent via broadcasts.
    if err := p.sendTransactions(pm.txpool.GetTransactions()); err != nil {
        return err
    }

    // main loop. handle incoming messages.
    for {
        if err := pm.handleMsg(p); err != nil {
            return err
        }
    }

    return nil
}

func (self *EthProtocolManager) handleMsg(p *peer) error {
    msg, err := p.rw.ReadMsg()
    if err != nil {
        return err
    }
    if msg.Size > ProtocolMaxMsgSize {
        return errResp(ErrMsgTooLarge, "%v > %v", msg.Size, ProtocolMaxMsgSize)
    }
    // make sure that the payload has been fully consumed
    defer msg.Discard()

    switch msg.Code {
    case GetTxMsg: // ignore
    case StatusMsg:
        return errResp(ErrExtraStatusMsg, "uncontrolled status message")

    case TxMsg:
        // TODO: rework using lazy RLP stream
        var txs []*types.Transaction
        if err := msg.Decode(&txs); err != nil {
            return errResp(ErrDecode, "msg %v: %v", msg, err)
        }
        for i, tx := range txs {
            if tx == nil {
                return errResp(ErrDecode, "transaction %d is nil", i)
            }
            jsonlogger.LogJson(&logger.EthTxReceived{
                TxHash:   tx.Hash().Hex(),
                RemoteId: p.ID().String(),
            })
        }
        self.txpool.AddTransactions(txs)

    case GetBlockHashesMsg:
        var request getBlockHashesMsgData
        if err := msg.Decode(&request); err != nil {
            return errResp(ErrDecode, "->msg %v: %v", msg, err)
        }

        if request.Amount > maxHashes {
            request.Amount = maxHashes
        }
        hashes := self.chainman.GetBlockHashesFromHash(request.Hash, request.Amount)
        return p.sendBlockHashes(hashes)
    case BlockHashesMsg:
        msgStream := rlp.NewStream(msg.Payload)

        var hashes []common.Hash
        if err := msgStream.Decode(&hashes); err != nil {
            break
        }
        self.downloader.HashCh <- hashes

    case GetBlocksMsg:
        msgStream := rlp.NewStream(msg.Payload)
        if _, err := msgStream.List(); err != nil {
            return err
        }

        var blocks []*types.Block
        var i int
        for {
            i++
            var hash common.Hash
            err := msgStream.Decode(&hash)
            if err == rlp.EOL {
                break
            } else if err != nil {
                return errResp(ErrDecode, "msg %v: %v", msg, err)
            }

            block := self.chainman.GetBlock(hash)
            if block != nil {
                blocks = append(blocks, block)
            }
            if i == maxBlocks {
                break
            }
        }
        return p.sendBlocks(blocks)
    case BlocksMsg:
        msgStream := rlp.NewStream(msg.Payload)

        var blocks []*types.Block
        if err := msgStream.Decode(&blocks); err != nil {
            glog.V(logger.Detail).Infoln("Decode error", err)
            fmt.Println("decode error", err)
            blocks = nil
        }
        self.downloader.DeliverChunk(p.id, blocks)

    case NewBlockMsg:
        var request newBlockMsgData
        if err := msg.Decode(&request); err != nil {
            return errResp(ErrDecode, "%v: %v", msg, err)
        }
        if err := request.Block.ValidateFields(); err != nil {
            return errResp(ErrDecode, "block validation %v: %v", msg, err)
        }
        hash := request.Block.Hash()
        _, chainHead, _ := self.chainman.Status()

        jsonlogger.LogJson(&logger.EthChainReceivedNewBlock{
            BlockHash:     hash.Hex(),
            BlockNumber:   request.Block.Number(), // this surely must be zero
            ChainHeadHash: chainHead.Hex(),
            BlockPrevHash: request.Block.ParentHash().Hex(),
            RemoteId:      p.ID().String(),
        })
        self.downloader.AddBlock(p.id, request.Block, request.TD)

    default:
        return errResp(ErrInvalidMsgCode, "%v", msg.Code)
    }
    return nil
}