path: root/swarm/network/stream/delivery.go

// Copyright 2018 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 stream

import (
    "errors"
    "time"

    "github.com/ethereum/go-ethereum/common"
    "github.com/ethereum/go-ethereum/metrics"
    "github.com/ethereum/go-ethereum/p2p/discover"
    "github.com/ethereum/go-ethereum/swarm/log"
    "github.com/ethereum/go-ethereum/swarm/network"
    "github.com/ethereum/go-ethereum/swarm/storage"
)

const (
    swarmChunkServerStreamName = "RETRIEVE_REQUEST"
    deliveryCap                = 32
)

var (
    processReceivedChunksCount    = metrics.NewRegisteredCounter("network.stream.received_chunks.count", nil)
    handleRetrieveRequestMsgCount = metrics.NewRegisteredCounter("network.stream.handle_retrieve_request_msg.count", nil)

    requestFromPeersCount     = metrics.NewRegisteredCounter("network.stream.request_from_peers.count", nil)
    requestFromPeersEachCount = metrics.NewRegisteredCounter("network.stream.request_from_peers_each.count", nil)
)

type Delivery struct {
    db       *storage.DBAPI
    overlay  network.Overlay
    receiveC chan *ChunkDeliveryMsg
    getPeer  func(discover.NodeID) *Peer
}

func NewDelivery(overlay network.Overlay, db *storage.DBAPI) *Delivery {
    d := &Delivery{
        db:       db,
        overlay:  overlay,
        receiveC: make(chan *ChunkDeliveryMsg, deliveryCap),
    }

    go d.processReceivedChunks()
    return d
}

// SwarmChunkServer implements Server
type SwarmChunkServer struct {
    deliveryC  chan []byte
    batchC     chan []byte
    db         *storage.DBAPI
    currentLen uint64
    quit       chan struct{}
}

// NewSwarmChunkServer is SwarmChunkServer constructor
func NewSwarmChunkServer(db *storage.DBAPI) *SwarmChunkServer {
    s := &SwarmChunkServer{
        deliveryC: make(chan []byte, deliveryCap),
        batchC:    make(chan []byte),
        db:        db,
        quit:      make(chan struct{}),
    }
    go s.processDeliveries()
    return s
}

// processDeliveries handles delivered chunk hashes
func (s *SwarmChunkServer) processDeliveries() {
    var hashes []byte
    var batchC chan []byte
    for {
        select {
        case <-s.quit:
            return
        case hash := <-s.deliveryC:
            hashes = append(hashes, hash...)
            batchC = s.batchC
        case batchC <- hashes:
            hashes = nil
            batchC = nil
        }
    }
}

// SetNextBatch
func (s *SwarmChunkServer) SetNextBatch(_, _ uint64) (hashes []byte, from uint64, to uint64, proof *HandoverProof, err error) {
    select {
    case hashes = <-s.batchC:
    case <-s.quit:
        return
    }

    from = s.currentLen
    s.currentLen += uint64(len(hashes))
    to = s.currentLen
    return
}

// Close needs to be called on a stream server
func (s *SwarmChunkServer) Close() {
    close(s.quit)
}

// GetData retrives chunk data from db store
func (s *SwarmChunkServer) GetData(key []byte) ([]byte, error) {
    chunk, err := s.db.Get(storage.Address(key))
    if err == storage.ErrFetching {
        <-chunk.ReqC
    } else if err != nil {
        return nil, err
    }
    return chunk.SData, nil
}

// RetrieveRequestMsg is the protocol msg for chunk retrieve requests
type RetrieveRequestMsg struct {
    Addr      storage.Address
    SkipCheck bool
}

func (d *Delivery) handleRetrieveRequestMsg(sp *Peer, req *RetrieveRequestMsg) error {
    log.Trace("received request", "peer", sp.ID(), "hash", req.Addr)
    handleRetrieveRequestMsgCount.Inc(1)

    s, err := sp.getServer(NewStream(swarmChunkServerStreamName, "", false))
    if err != nil {
        return err
    }
    streamer := s.Server.(*SwarmChunkServer)
    chunk, created := d.db.GetOrCreateRequest(req.Addr)
    if chunk.ReqC != nil {
        if created {
            if err := d.RequestFromPeers(chunk.Addr[:], true, sp.ID()); err != nil {
                log.Warn("unable to forward chunk request", "peer", sp.ID(), "key", chunk.Addr, "err", err)
                chunk.SetErrored(storage.ErrChunkForward)
                return nil
            }
        }
        go func() {
            t := time.NewTimer(10 * time.Minute)
            defer t.Stop()

            log.Debug("waiting delivery", "peer", sp.ID(), "hash", req.Addr, "node", common.Bytes2Hex(d.overlay.BaseAddr()), "created", created)
            start := time.Now()
            select {
            case <-chunk.ReqC:
                log.Debug("retrieve request ReqC closed", "peer", sp.ID(), "hash", req.Addr, "time", time.Since(start))
            case <-t.C:
                log.Debug("retrieve request timeout", "peer", sp.ID(), "hash", req.Addr)
                chunk.SetErrored(storage.ErrChunkTimeout)
                return
            }
            chunk.SetErrored(nil)

            if req.SkipCheck {
                err := sp.Deliver(chunk, s.priority)
                if err != nil {
                    log.Warn("ERROR in handleRetrieveRequestMsg, DROPPING peer!", "err", err)
                    sp.Drop(err)
                }
            }
            streamer.deliveryC <- chunk.Addr[:]
        }()
        return nil
    }
    // TODO: call the retrieve function of the outgoing syncer
    if req.SkipCheck {
        log.Trace("deliver", "peer", sp.ID(), "hash", chunk.Addr)
        if length := len(chunk.SData); length < 9 {
            log.Error("Chunk.SData to deliver is too short", "len(chunk.SData)", length, "address", chunk.Addr)
        }
        return sp.Deliver(chunk, s.priority)
    }
    streamer.deliveryC <- chunk.Addr[:]
    return nil
}

type ChunkDeliveryMsg struct {
    Addr  storage.Address
    SData []byte // the stored chunk Data (incl size)
    peer  *Peer  // set in handleChunkDeliveryMsg
}

func (d *Delivery) handleChunkDeliveryMsg(sp *Peer, req *ChunkDeliveryMsg) error {
    req.peer = sp
    d.receiveC <- req
    return nil
}

func (d *Delivery) processReceivedChunks() {
R:
    for req := range d.receiveC {
        processReceivedChunksCount.Inc(1)

        // this should be has locally
        chunk, err := d.db.Get(req.Addr)
        if err == nil {
            continue R
        }
        if err != storage.ErrFetching {
            log.Error("processReceivedChunks db error", "addr", req.Addr, "err", err, "chunk", chunk)
            continue R
        }
        select {
        case <-chunk.ReqC:
            log.Error("someone else delivered?", "hash", chunk.Addr.Hex())
            continue R
        default:
        }
        chunk.SData = req.SData
        d.db.Put(chunk)

        go func(req *ChunkDeliveryMsg) {
            err := chunk.WaitToStore()
            if err == storage.ErrChunkInvalid {
                req.peer.Drop(err)
            }
        }(req)
    }
}

// RequestFromPeers sends a chunk retrieve request to
func (d *Delivery) RequestFromPeers(hash []byte, skipCheck bool, peersToSkip ...discover.NodeID) error {
    var success bool
    var err error
    requestFromPeersCount.Inc(1)
    d.overlay.EachConn(hash, 255, func(p network.OverlayConn, po int, nn bool) bool {
        spId := p.(network.Peer).ID()
        for _, p := range peersToSkip {
            if p == spId {
                log.Trace("Delivery.RequestFromPeers: skip peer", "peer", spId)
                return true
            }
        }
        sp := d.getPeer(spId)
        if sp == nil {
            log.Warn("Delivery.RequestFromPeers: peer not found", "id", spId)
            return true
        }
        // TODO: skip light nodes that do not accept retrieve requests
        err = sp.SendPriority(&RetrieveRequestMsg{
            Addr:      hash,
            SkipCheck: skipCheck,
        }, Top)
        if err != nil {
            return true
        }
        requestFromPeersEachCount.Inc(1)
        success = true
        return false
    })
    if success {
        return nil
    }
    return errors.New("no peer found")
}