swarm/network: update syncing

swarm/network/stream/peer.go

@@ -24,8 +24,10 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/metrics"
-	"github.com/ethereum/go-ethereum/p2p/protocols"
+	"github.com/ethereum/go-ethereum/p2p"
+	"github.com/ethereum/go-ethereum/swarm/chunk"
 	"github.com/ethereum/go-ethereum/swarm/log"
+	"github.com/ethereum/go-ethereum/swarm/network"
 	pq "github.com/ethereum/go-ethereum/swarm/network/priorityqueue"
 	"github.com/ethereum/go-ethereum/swarm/network/stream/intervals"
 	"github.com/ethereum/go-ethereum/swarm/spancontext"
@@ -54,7 +56,7 @@ var ErrMaxPeerServers = errors.New("max peer servers")
 
 // Peer is the Peer extension for the streaming protocol
 type Peer struct {
-	*protocols.Peer
+	*network.BzzPeer
 	streamer *Registry
 	pq       *pq.PriorityQueue
 	serverMu sync.RWMutex
@@ -74,9 +76,9 @@ type WrappedPriorityMsg struct {
 }
 
 // NewPeer is the constructor for Peer
-func NewPeer(peer *protocols.Peer, streamer *Registry) *Peer {
+func NewPeer(peer *network.BzzPeer, streamer *Registry) *Peer {
 	p := &Peer{
-		Peer:         peer,
+		BzzPeer:      peer,
 		pq:           pq.New(int(PriorityQueue), PriorityQueueCap),
 		streamer:     streamer,
 		servers:      make(map[Stream]*server),
@@ -417,3 +419,165 @@ func (p *Peer) close() {
 		s.Close()
 	}
 }
+
+// runUpdateSyncing is a long running function that creates the initial
+// syncing subscriptions to the peer and waits for neighbourhood depth change
+// to create new ones or quit existing ones based on the new neighbourhood depth
+// and if peer enters or leaves nearest neighbourhood by using
+// syncSubscriptionsDiff and updateSyncSubscriptions functions.
+func (p *Peer) runUpdateSyncing() {
+	timer := time.NewTimer(p.streamer.syncUpdateDelay)
+	defer timer.Stop()
+
+	select {
+	case <-timer.C:
+	case <-p.streamer.quit:
+		return
+	}
+
+	kad := p.streamer.delivery.kad
+	po := chunk.Proximity(p.BzzAddr.Over(), kad.BaseAddr())
+
+	depth := kad.NeighbourhoodDepth()
+
+	log.Debug("update syncing subscriptions: initial", "peer", p.ID(), "po", po, "depth", depth)
+
+	// initial subscriptions
+	p.updateSyncSubscriptions(syncSubscriptionsDiff(po, -1, depth, kad.MaxProxDisplay))
+
+	depthChangeSignal, unsubscribeDepthChangeSignal := kad.SubscribeToNeighbourhoodDepthChange()
+	defer unsubscribeDepthChangeSignal()
+
+	prevDepth := depth
+	for {
+		select {
+		case _, ok := <-depthChangeSignal:
+			if !ok {
+				return
+			}
+			// update subscriptions for this peer when depth changes
+			depth := kad.NeighbourhoodDepth()
+			log.Debug("update syncing subscriptions", "peer", p.ID(), "po", po, "depth", depth)
+			p.updateSyncSubscriptions(syncSubscriptionsDiff(po, prevDepth, depth, kad.MaxProxDisplay))
+			prevDepth = depth
+		case <-p.streamer.quit:
+			return
+		}
+	}
+	log.Debug("update syncing subscriptions: exiting", "peer", p.ID())
+}
+
+// updateSyncSubscriptions accepts two slices of integers, the first one
+// representing proximity order bins for required syncing subscriptions
+// and the second one representing bins for syncing subscriptions that
+// need to be removed. This function sends request for subscription
+// messages and quit messages for provided bins.
+func (p *Peer) updateSyncSubscriptions(subBins, quitBins []int) {
+	if p.streamer.getPeer(p.ID()) == nil {
+		log.Debug("update syncing subscriptions", "peer not found", p.ID())
+		return
+	}
+	log.Debug("update syncing subscriptions", "peer", p.ID(), "subscribe", subBins, "quit", quitBins)
+	for _, po := range subBins {
+		p.subscribeSync(po)
+	}
+	for _, po := range quitBins {
+		p.quitSync(po)
+	}
+}
+
+// subscribeSync send the request for syncing subscriptions to the peer
+// using subscriptionFunc. This function is used to request syncing subscriptions
+// when new peer is added to the registry and on neighbourhood depth change.
+func (p *Peer) subscribeSync(po int) {
+	err := subscriptionFunc(p.streamer, p.ID(), uint8(po))
+	if err != nil {
+		log.Error("subscription", "err", err)
+	}
+}
+
+// quitSync sends the quit message for live and history syncing streams to the peer.
+// This function is used in runUpdateSyncing indirectly over updateSyncSubscriptions
+// to remove unneeded syncing subscriptions on neighbourhood depth change.
+func (p *Peer) quitSync(po int) {
+	live := NewStream("SYNC", FormatSyncBinKey(uint8(po)), true)
+	history := getHistoryStream(live)
+	err := p.streamer.Quit(p.ID(), live)
+	if err != nil && err != p2p.ErrShuttingDown {
+		log.Error("quit", "err", err, "peer", p.ID(), "stream", live)
+	}
+	err = p.streamer.Quit(p.ID(), history)
+	if err != nil && err != p2p.ErrShuttingDown {
+		log.Error("quit", "err", err, "peer", p.ID(), "stream", history)
+	}
+
+	err = p.removeServer(live)
+	if err != nil {
+		log.Error("remove server", "err", err, "peer", p.ID(), "stream", live)
+	}
+	err = p.removeServer(history)
+	if err != nil {
+		log.Error("remove server", "err", err, "peer", p.ID(), "stream", live)
+	}
+}
+
+// syncSubscriptionsDiff calculates to which proximity order bins a peer
+// (with po peerPO) needs to be subscribed after kademlia neighbourhood depth
+// change from prevDepth to newDepth. Max argument limits the number of
+// proximity order bins. Returned values are slices of integers which represent
+// proximity order bins, the first one to which additional subscriptions need to
+// be requested and the second one which subscriptions need to be quit. Argument
+// prevDepth with value less then 0 represents no previous depth, used for
+// initial syncing subscriptions.
+func syncSubscriptionsDiff(peerPO, prevDepth, newDepth, max int) (subBins, quitBins []int) {
+	newStart, newEnd := syncBins(peerPO, newDepth, max)
+	if prevDepth < 0 {
+		// no previous depth, return the complete range
+		// for subscriptions requests and nothing for quitting
+		return intRange(newStart, newEnd), nil
+	}
+
+	prevStart, prevEnd := syncBins(peerPO, prevDepth, max)
+
+	if newStart < prevStart {
+		subBins = append(subBins, intRange(newStart, prevStart)...)
+	}
+
+	if prevStart < newStart {
+		quitBins = append(quitBins, intRange(prevStart, newStart)...)
+	}
+
+	if newEnd < prevEnd {
+		quitBins = append(quitBins, intRange(newEnd, prevEnd)...)
+	}
+
+	if prevEnd < newEnd {
+		subBins = append(subBins, intRange(prevEnd, newEnd)...)
+	}
+
+	return subBins, quitBins
+}
+
+// syncBins returns the range to which proximity order bins syncing
+// subscriptions need to be requested, based on peer proximity and
+// kademlia neighbourhood depth. Returned range is [start,end), inclusive for
+// start and exclusive for end.
+func syncBins(peerPO, depth, max int) (start, end int) {
+	if peerPO < depth {
+		// subscribe only to peerPO bin if it is not
+		// in the nearest neighbourhood
+		return peerPO, peerPO + 1
+	}
+	// subscribe from depth to max bin if the peer
+	// is in the nearest neighbourhood
+	return depth, max + 1
+}
+
+// intRange returns the slice of integers [start,end). The start
+// is inclusive and the end is not.
+func intRange(start, end int) (r []int) {
+	for i := start; i < end; i++ {
+		r = append(r, i)
+	}
+	return r
+}