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 (
    "context"
    "errors"
    "fmt"
    "time"

    "github.com/ethereum/go-ethereum/metrics"
    "github.com/ethereum/go-ethereum/p2p/enode"
    "github.com/ethereum/go-ethereum/swarm/chunk"
    "github.com/ethereum/go-ethereum/swarm/log"
    "github.com/ethereum/go-ethereum/swarm/network"
    "github.com/ethereum/go-ethereum/swarm/spancontext"
    "github.com/ethereum/go-ethereum/swarm/storage"
    "github.com/ethereum/go-ethereum/swarm/tracing"
    opentracing "github.com/opentracing/opentracing-go"
    olog "github.com/opentracing/opentracing-go/log"
)

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

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

    lastReceivedChunksMsg = metrics.GetOrRegisterGauge("network.stream.received_chunks", nil)
)

type Delivery struct {
    netStore *storage.NetStore
    kad      *network.Kademlia
    getPeer  func(enode.ID) *Peer
    quit     chan struct{}
}

func NewDelivery(kad *network.Kademlia, netStore *storage.NetStore) *Delivery {
    return &Delivery{
        netStore: netStore,
        kad:      kad,
        quit:     make(chan struct{}),
    }
}

// RetrieveRequestMsg is the protocol msg for chunk retrieve requests
type RetrieveRequestMsg struct {
    Addr      storage.Address
    SkipCheck bool
    HopCount  uint8
}

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

    var osp opentracing.Span
    ctx, osp = spancontext.StartSpan(
        ctx,
        "stream.handle.retrieve")

    osp.LogFields(olog.String("ref", req.Addr.String()))

    var cancel func()
    // TODO: do something with this hardcoded timeout, maybe use TTL in the future
    ctx = context.WithValue(ctx, "peer", sp.ID().String())
    ctx = context.WithValue(ctx, "hopcount", req.HopCount)
    ctx, cancel = context.WithTimeout(ctx, network.RequestTimeout)

    go func() {
        select {
        case <-ctx.Done():
        case <-d.quit:
        }
        cancel()
    }()

    go func() {
        defer osp.Finish()
        ch, err := d.netStore.Get(ctx, chunk.ModeGetRequest, req.Addr)
        if err != nil {
            retrieveChunkFail.Inc(1)
            log.Debug("ChunkStore.Get can not retrieve chunk", "peer", sp.ID().String(), "addr", req.Addr, "hopcount", req.HopCount, "err", err)
            return
        }
        syncing := false

        err = sp.Deliver(ctx, ch, Top, syncing)
        if err != nil {
            log.Warn("ERROR in handleRetrieveRequestMsg", "err", err)
        }
        osp.LogFields(olog.Bool("delivered", true))
    }()

    return nil
}

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

//...but swap accounting needs to disambiguate if it is a delivery for syncing or for retrieval
//as it decides based on message type if it needs to account for this message or not

//defines a chunk delivery for retrieval (with accounting)
type ChunkDeliveryMsgRetrieval ChunkDeliveryMsg

//defines a chunk delivery for syncing (without accounting)
type ChunkDeliveryMsgSyncing ChunkDeliveryMsg

// chunk delivery msg is response to retrieverequest msg
func (d *Delivery) handleChunkDeliveryMsg(ctx context.Context, sp *Peer, req interface{}) error {
    var osp opentracing.Span
    ctx, osp = spancontext.StartSpan(
        ctx,
        "handle.chunk.delivery")

    processReceivedChunksCount.Inc(1)

    // record the last time we received a chunk delivery message
    lastReceivedChunksMsg.Update(time.Now().UnixNano())

    var msg *ChunkDeliveryMsg
    var mode chunk.ModePut
    switch r := req.(type) {
    case *ChunkDeliveryMsgRetrieval:
        msg = (*ChunkDeliveryMsg)(r)
        peerPO := chunk.Proximity(sp.BzzAddr.Over(), msg.Addr)
        po := chunk.Proximity(d.kad.BaseAddr(), msg.Addr)
        depth := d.kad.NeighbourhoodDepth()
        // chunks within the area of responsibility should always sync
        // https://github.com/ethersphere/go-ethereum/pull/1282#discussion_r269406125
        if po >= depth || peerPO < po {
            mode = chunk.ModePutSync
        } else {
            // do not sync if peer that is sending us a chunk is closer to the chunk then we are
            mode = chunk.ModePutRequest
        }
    case *ChunkDeliveryMsgSyncing:
        msg = (*ChunkDeliveryMsg)(r)
        mode = chunk.ModePutSync
    case *ChunkDeliveryMsg:
        msg = r
        mode = chunk.ModePutSync
    }

    log.Trace("handle.chunk.delivery", "ref", msg.Addr, "from peer", sp.ID())

    go func() {
        defer osp.Finish()

        msg.peer = sp
        log.Trace("handle.chunk.delivery", "put", msg.Addr)
        _, err := d.netStore.Put(ctx, mode, storage.NewChunk(msg.Addr, msg.SData))
        if err != nil {
            if err == storage.ErrChunkInvalid {
                // we removed this log because it spams the logs
                // TODO: Enable this log line
                // log.Warn("invalid chunk delivered", "peer", sp.ID(), "chunk", msg.Addr, )
                msg.peer.Drop()
            }
        }
        log.Trace("handle.chunk.delivery", "done put", msg.Addr, "err", err)
    }()
    return nil
}

func (d *Delivery) Close() {
    close(d.quit)
}

// RequestFromPeers sends a chunk retrieve request to a peer
// The most eligible peer that hasn't already been sent to is chosen
// TODO: define "eligible"
func (d *Delivery) RequestFromPeers(ctx context.Context, req *network.Request) (*enode.ID, chan struct{}, error) {
    requestFromPeersCount.Inc(1)
    var sp *Peer
    spID := req.Source

    if spID != nil {
        sp = d.getPeer(*spID)
        if sp == nil {
            return nil, nil, fmt.Errorf("source peer %v not found", spID.String())
        }
    } else {
        d.kad.EachConn(req.Addr[:], 255, func(p *network.Peer, po int) bool {
            id := p.ID()
            if p.LightNode {
                // skip light nodes
                return true
            }
            if req.SkipPeer(id.String()) {
                log.Trace("Delivery.RequestFromPeers: skip peer", "peer id", id)
                return true
            }
            sp = d.getPeer(id)
            // sp is nil, when we encounter a peer that is not registered for delivery, i.e. doesn't support the `stream` protocol
            if sp == nil {
                return true
            }
            spID = &id
            return false
        })
        if sp == nil {
            return nil, nil, errors.New("no peer found")
        }
    }

    // setting this value in the context creates a new span that can persist across the sendpriority queue and the network roundtrip
    // this span will finish only when delivery is handled (or times out)
    ctx = context.WithValue(ctx, tracing.StoreLabelId, "stream.send.request")
    ctx = context.WithValue(ctx, tracing.StoreLabelMeta, fmt.Sprintf("%v.%v", sp.ID(), req.Addr))
    log.Trace("request.from.peers", "peer", sp.ID(), "ref", req.Addr)
    err := sp.SendPriority(ctx, &RetrieveRequestMsg{
        Addr:      req.Addr,
        SkipCheck: req.SkipCheck,
        HopCount:  req.HopCount,
    }, Top)
    if err != nil {
        return nil, nil, err
    }
    requestFromPeersEachCount.Inc(1)

    return spID, sp.quit, nil
}