Kademlia: Initial bucket refresh implementation. This might be improved down the road.

Bootstrap.go

@@ -98,7 +98,7 @@ func (peer *rootPeer) contact() {
 	contactArbitraryPeer(peer.publicKey, peer.addresses)
 }
 
-// bootstrap connects to the initial set of peers. It will also start the routine for ongoing sending of multicast/broadcast messages.
+// bootstrap connects to the initial set of peers.
 func bootstrap() {
 	if len(rootPeers) == 0 {
 		log.Printf("bootstrap warning: Empty list of root peers. Connectivity relies on local peer discovery and incoming connections.\n")

Kademlia.go

@@ -56,20 +56,43 @@ func initKademlia() {
 			node.Info.(*PeerInfo).sendAnnouncementFindValue(request)
 		}
 	}
+}
 
-	// Refresh buckets every 5 minutes to meet the alpha nodes per bucket target. Force full refresh every hour.
-	go func() {
-		for minute := 5; ; minute += 5 {
-			time.Sleep(time.Minute * 5)
+// autoBucketRefresh refreshes buckets every 5 minutes to meet the alpha nodes per bucket target. Force full refresh every hour.
+func autoBucketRefresh() {
+	for minute := 5; ; minute += 5 {
+		time.Sleep(time.Minute * 5)
 
-			target := alpha
-			if minute%60 == 0 {
-				target = 0
-			}
-
-			nodesDHT.RefreshBuckets(target)
+		target := alpha
+		if minute%60 == 0 {
+			target = 0
 		}
-	}()
+
+		nodesDHT.RefreshBuckets(target)
+	}
+}
+
+// bootstrapKademlia bootstraps the Kademlia bucket list
+func bootstrapKademlia() {
+	monitor := make(chan *PeerInfo)
+	registerPeerMonitor(monitor)
+
+	// Wait until there are at least 2 peers connected.
+	for {
+		<-monitor
+		if nodesDHT.NumNodes() >= 2 {
+			break
+		}
+	}
+
+	unregisterPeerMonitor(monitor)
+
+	// Refresh every 10 seconds 3 times
+	for n := 0; n < 3; n++ {
+		nodesDHT.RefreshBuckets(alpha)
+
+		time.Sleep(time.Second)
+	}
 }
 
 // Future sendAnnouncementX: If it detects that announcements are sent out to the same peer within 50ms it should activate a wait-and-group scheme.

Peer ID.go

@@ -113,6 +113,14 @@ func PeerlistAdd(PublicKey *btcec.PublicKey, connections ...*Connection) (peer *
 	// add to Kademlia
 	nodesDHT.AddNode(&dht.Node{ID: peer.NodeID, Info: peer})
 
+	// send to all channels non-blocking
+	for _, monitor := range peerMonitor {
+		select {
+		case monitor <- peer:
+		default:
+		}
+	}
+
 	return peer, true
 }
 
@@ -201,3 +209,30 @@ func selfPeerRecord(network *Network) (result PeerRecord) {
 		LastContact: 0,
 	}
 }
+
+var peerMonitor []chan<- *PeerInfo
+
+// registerPeerMonitor registers a channel to receive all new peers
+func registerPeerMonitor(channel chan<- *PeerInfo) {
+	peerlistMutex.Lock()
+	defer peerlistMutex.Unlock()
+
+	peerMonitor = append(peerMonitor, channel)
+}
+
+// unregisterPeerMonitor unregisters a channel
+func unregisterPeerMonitor(channel chan<- *PeerInfo) {
+	peerlistMutex.Lock()
+	defer peerlistMutex.Unlock()
+
+	for n, channel2 := range peerMonitor {
+		if channel == channel2 {
+			peerMonitorNew := peerMonitor[:n]
+			if n < len(peerMonitor)-1 {
+				peerMonitorNew = append(peerMonitorNew, peerMonitor[n+1:]...)
+			}
+			peerMonitor = peerMonitorNew
+			break
+		}
+	}
+}

Peernet.go

@@ -20,8 +20,10 @@ func Init() {
 
 // Connect starts bootstrapping and local peer discovery.
 func Connect() {
+	go bootstrapKademlia()
 	go bootstrap()
 	go autoMulticastBroadcast()
 	go autoPingAll()
 	go networkChangeMonitor()
+	go autoBucketRefresh()
 }

README.md

@@ -83,6 +83,8 @@ The Private Key is required to make any changes to the user's blockchain, includ
   * Check every 10 seconds for new/removed network interfaces and for new/removed IPs.
   * Automatically listen on any newly detected network interfaces and IPs.
   * Start a full Kademlia bucket refresh in case of a new network interface or IP.
+* Kademlia bootstrap:
+  * As soon as there are at least 2 peers, keep refreshing buckets (target number is alpha) every 10 seconds 3 times.
 
 ### Ping
 

go.mod

@@ -3,7 +3,7 @@ module github.com/PeernetOfficial/core
 go 1.16
 
 require (
-	github.com/PeernetOfficial/core/dht v0.0.0-20210424204239-6693d442a6e2
+	github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9
 	github.com/btcsuite/btcd v0.21.0-beta.0.20210401013323-36a96f6a0025
 	github.com/pkg/errors v0.9.1
 	golang.org/x/crypto v0.0.0-20210415154028-4f45737414dc

go.sum

@@ -1,5 +1,5 @@
-github.com/PeernetOfficial/core/dht v0.0.0-20210424204239-6693d442a6e2 h1:h4EP52078qatwYoW1DztuQhg5Y8i9wwDbkdO92usM+o=
-github.com/PeernetOfficial/core/dht v0.0.0-20210424204239-6693d442a6e2/go.mod h1:sb2H21VIVTohCXVrDFo/Skl2tN8Yzba+MXSS6NgCYXw=
+github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9 h1:kcjoWZl9GZ9uSajS6t0tiKDpaatUQ64tl3OqXPc+YsY=
+github.com/PeernetOfficial/core/dht v0.0.0-20210425014452-611dfa3b1ce9/go.mod h1:sb2H21VIVTohCXVrDFo/Skl2tN8Yzba+MXSS6NgCYXw=
 github.com/aead/siphash v1.0.1/go.mod h1:Nywa3cDsYNNK3gaciGTWPwHt0wlpNV15vwmswBAUSII=
 github.com/btcsuite/btcd v0.20.1-beta/go.mod h1:wVuoA8VJLEcwgqHBwHmzLRazpKxTv13Px/pDuV7OomQ=
 github.com/btcsuite/btcd v0.21.0-beta.0.20210401013323-36a96f6a0025 h1:aoVqvZk4mLyF3WZbqEVPq+vXnwL2wekZg4P4mjYJNLs=