[NOD-114] On start, DNSSeeder should update its addresses more frequently (#250)

* [NOD-114] Added a minimum address amount GetAddrs.

* [NOD-114] Added smallNetwork intervals for when the network is small.

* [NOD-114] Fixed bad minimum address calculation.

addrmgr/addrmanager.go

@@ -160,6 +160,10 @@ const (
 	// will consider evicting an address.
 	minBadDays = 7
 
+	// getAddrMin is the least addresses that we will send in response
+	// to a getAddr. If we have less than this amount, we send everything.
+	getAddrMin = 50
+
 	// getAddrMax is the most addresses that we will send in response
 	// to a getAddr (in practise the most addresses we will return from a
 	// call to AddressCache()).
@@ -844,6 +848,12 @@ func (a *AddrManager) AddressCache(includeAllSubnetworks bool, subnetworkID *sub
 	if numAddresses > getAddrMax {
 		numAddresses = getAddrMax
 	}
+	if len(allAddr) < getAddrMin {
+		numAddresses = len(allAddr)
+	}
+	if len(allAddr) > getAddrMin && numAddresses < getAddrMin {
+		numAddresses = getAddrMin
+	}
 
 	// Fisher-Yates shuffle the array. We only need to do the first
 	// `numAddresses' since we are throwing the rest.

dnsseeder/dnsseed.go

@@ -92,8 +92,9 @@ func creep() {
 			peers = amgr.Addresses()
 		}
 		if len(peers) == 0 {
-			log.Printf("No stale addresses -- sleeping for 10 minutes")
-			for i := 0; i < 600; i++ {
+			creepIntervalInSeconds := int(amgr.creepInterval().Seconds())
+			log.Printf("No stale addresses -- sleeping for %d seconds", creepIntervalInSeconds)
+			for i := 0; i < creepIntervalInSeconds; i++ {
 				time.Sleep(time.Second)
 				if atomic.LoadInt32(&systemShutdown) != 0 {
 					log.Printf("Creep thread shutdown")

dnsseeder/manager.go

@@ -45,6 +45,10 @@ const (
 	// stale.
 	defaultStaleTimeout = time.Hour
 
+	// smallNetworkStaleTimeout is the time in which a host is considered
+	// stale if the network is small.
+	smallNetworkStaleTimeout = time.Second * 30
+
 	// dumpAddressInterval is the interval used to dump the address
 	// cache to disk for future use.
 	dumpAddressInterval = time.Second * 30
@@ -59,6 +63,18 @@ const (
 	// pruneExpireTimeout is the expire time in which a node is
 	// considered dead.
 	pruneExpireTimeout = time.Hour * 8
+
+	// defaultCreepInterval is the interval between creep runs.
+	defaultCreepInterval = time.Minute * 10
+
+	// defaultCreepInterval is the interval between creep runs if the
+	// network is small.
+	smallNetworkCreepInterval = time.Second * 30
+
+	// smallNetworkNodeAmount is amount of nodes under which a network
+	// is considered small. A small network has shorter timeouts and
+	// intervals to encourage faster network growth.
+	smallNetworkNodeAmount = 50
 )
 
 var (
@@ -181,8 +197,8 @@ func (m *Manager) Addresses() []*wire.NetAddress {
 		if i == 0 {
 			break
 		}
-		if now.Sub(node.LastSuccess) < defaultStaleTimeout ||
-			now.Sub(node.LastAttempt) < defaultStaleTimeout {
+		if now.Sub(node.LastSuccess) < m.staleTimeout() ||
+			now.Sub(node.LastAttempt) < m.staleTimeout() {
 			continue
 		}
 		addrs = append(addrs, node.Addr)
@@ -198,6 +214,22 @@ func (m *Manager) AddressCount() int {
 	return len(m.nodes)
 }
 
+func (m *Manager) staleTimeout() time.Duration {
+	if m.AddressCount() < smallNetworkNodeAmount {
+		return smallNetworkStaleTimeout
+	}
+
+	return defaultStaleTimeout
+}
+
+func (m *Manager) creepInterval() time.Duration {
+	if m.AddressCount() < smallNetworkNodeAmount {
+		return smallNetworkCreepInterval
+	}
+
+	return defaultCreepInterval
+}
+
 // GoodAddresses returns good working IPs that match both the
 // passed DNS query type and have the requested services.
 func (m *Manager) GoodAddresses(qtype uint16, services wire.ServiceFlag, includeAllSubnetworks bool, subnetworkID *subnetworkid.SubnetworkID) []*wire.NetAddress {
@@ -230,7 +262,7 @@ func (m *Manager) GoodAddresses(qtype uint16, services wire.ServiceFlag, include
 		}
 
 		if node.LastSuccess.IsZero() ||
-			now.Sub(node.LastSuccess) > defaultStaleTimeout {
+			now.Sub(node.LastSuccess) > m.staleTimeout() {
 			continue
 		}