discosrv: Refactor handler loop

cmd/discosrv/main.go

@@ -28,10 +28,10 @@ var (
 	lock     sync.Mutex
 	queries  = 0
 	answered = 0
+	debug    = false
 )
 
 func main() {
-	var debug bool
 	var listen string
 	var timestamp bool
 
@@ -48,36 +48,17 @@ func main() {
 	addr, _ := net.ResolveUDPAddr("udp", listen)
 	conn, err := net.ListenUDP("udp", addr)
 	if err != nil {
-		panic(err)
+		log.Fatal(err)
 	}
 
-	go func() {
+	go logStats()
-		for {
-			time.Sleep(600 * time.Second)
-
-			lock.Lock()
-
-			var deleted = 0
-			for id, node := range nodes {
-				if time.Since(node.Updated) > 60*time.Minute {
-					delete(nodes, id)
-					deleted++
-				}
-			}
-			log.Printf("Expired %d nodes; %d nodes in registry; %d queries (%d answered)", deleted, len(nodes), queries, answered)
-			queries = 0
-			answered = 0
-
-			lock.Unlock()
-		}
-	}()
 
 	var buf = make([]byte, 1024)
 	for {
 		buf = buf[:cap(buf)]
 		n, addr, err := conn.ReadFromUDP(buf)
 		if err != nil {
-			panic(err)
+			log.Fatal(err)
 		}
 		if n < 4 {
 			log.Printf("Received short packet (%d bytes)", n)
@@ -89,149 +70,186 @@ func main() {
 
 		switch magic {
 		case discover.AnnouncementMagicV1:
-			var pkt discover.AnnounceV1
+			handleAnnounceV1(addr, buf)
-			err := pkt.UnmarshalXDR(buf)
-			if err != nil {
-				log.Println("AnnounceV1 Unmarshal:", err)
-				log.Println(hex.Dump(buf))
-				continue
-			}
-			if debug {
-				log.Printf("<- %v %#v", addr, pkt)
-			}
-
-			ip := addr.IP.To4()
-			if ip == nil {
-				ip = addr.IP.To16()
-			}
-			node := Node{
-				Addresses: []Address{{
-					IP:   ip,
-					Port: pkt.Port,
-				}},
-				Updated: time.Now(),
-			}
-
-			lock.Lock()
-			nodes[pkt.NodeID] = node
-			lock.Unlock()
 
 		case discover.QueryMagicV1:
-			var pkt discover.QueryV1
+			handleQueryV1(conn, addr, buf)
-			err := pkt.UnmarshalXDR(buf)
-			if err != nil {
-				log.Println("QueryV1 Unmarshal:", err)
-				log.Println(hex.Dump(buf))
-				continue
-			}
-			if debug {
-				log.Printf("<- %v %#v", addr, pkt)
-			}
-
-			lock.Lock()
-			node, ok := nodes[pkt.NodeID]
-			queries++
-			lock.Unlock()
-
-			if ok && len(node.Addresses) > 0 {
-				pkt := discover.AnnounceV1{
-					Magic:  discover.AnnouncementMagicV1,
-					NodeID: pkt.NodeID,
-					Port:   node.Addresses[0].Port,
-					IP:     node.Addresses[0].IP,
-				}
-				if debug {
-					log.Printf("-> %v %#v", addr, pkt)
-				}
-
-				tb := pkt.MarshalXDR()
-				_, _, err = conn.WriteMsgUDP(tb, nil, addr)
-				if err != nil {
-					log.Println("QueryV1 response write:", err)
-				}
-
-				lock.Lock()
-				answered++
-				lock.Unlock()
-			}
 
 		case discover.AnnouncementMagicV2:
-			var pkt discover.AnnounceV2
+			handleAnnounceV2(addr, buf)
-			err := pkt.UnmarshalXDR(buf)
-			if err != nil {
-				log.Println("AnnounceV2 Unmarshal:", err)
-				log.Println(hex.Dump(buf))
-				continue
-			}
-			if debug {
-				log.Printf("<- %v %#v", addr, pkt)
-			}
-
-			ip := addr.IP.To4()
-			if ip == nil {
-				ip = addr.IP.To16()
-			}
-
-			var addrs []Address
-			for _, addr := range pkt.Addresses {
-				tip := addr.IP
-				if len(tip) == 0 {
-					tip = ip
-				}
-				addrs = append(addrs, Address{
-					IP:   tip,
-					Port: addr.Port,
-				})
-			}
-
-			node := Node{
-				Addresses: addrs,
-				Updated:   time.Now(),
-			}
-
-			lock.Lock()
-			nodes[pkt.NodeID] = node
-			lock.Unlock()
 
 		case discover.QueryMagicV2:
-			var pkt discover.QueryV2
+			handleQueryV2(conn, addr, buf)
-			err := pkt.UnmarshalXDR(buf)
-			if err != nil {
-				log.Println("QueryV2 Unmarshal:", err)
-				log.Println(hex.Dump(buf))
-				continue
-			}
-			if debug {
-				log.Printf("<- %v %#v", addr, pkt)
-			}
-
-			lock.Lock()
-			node, ok := nodes[pkt.NodeID]
-			queries++
-			lock.Unlock()
-
-			if ok && len(node.Addresses) > 0 {
-				pkt := discover.AnnounceV2{
-					Magic:  discover.AnnouncementMagicV2,
-					NodeID: pkt.NodeID,
-				}
-				for _, addr := range node.Addresses {
-					pkt.Addresses = append(pkt.Addresses, discover.Address{IP: addr.IP, Port: addr.Port})
-				}
-				if debug {
-					log.Printf("-> %v %#v", addr, pkt)
-				}
-
-				tb := pkt.MarshalXDR()
-				_, _, err = conn.WriteMsgUDP(tb, nil, addr)
-				if err != nil {
-					log.Println("QueryV2 response write:", err)
-				}
-
-				lock.Lock()
-				answered++
-				lock.Unlock()
-			}
 		}
 	}
 }
+
+func handleAnnounceV1(addr *net.UDPAddr, buf []byte) {
+	var pkt discover.AnnounceV1
+	err := pkt.UnmarshalXDR(buf)
+	if err != nil {
+		log.Println("AnnounceV1 Unmarshal:", err)
+		log.Println(hex.Dump(buf))
+		return
+	}
+	if debug {
+		log.Printf("<- %v %#v", addr, pkt)
+	}
+
+	ip := addr.IP.To4()
+	if ip == nil {
+		ip = addr.IP.To16()
+	}
+	node := Node{
+		Addresses: []Address{{
+			IP:   ip,
+			Port: pkt.Port,
+		}},
+		Updated: time.Now(),
+	}
+
+	lock.Lock()
+	nodes[pkt.NodeID] = node
+	lock.Unlock()
+}
+
+func handleQueryV1(conn *net.UDPConn, addr *net.UDPAddr, buf []byte) {
+	var pkt discover.QueryV1
+	err := pkt.UnmarshalXDR(buf)
+	if err != nil {
+		log.Println("QueryV1 Unmarshal:", err)
+		log.Println(hex.Dump(buf))
+		return
+	}
+	if debug {
+		log.Printf("<- %v %#v", addr, pkt)
+	}
+
+	lock.Lock()
+	node, ok := nodes[pkt.NodeID]
+	queries++
+	lock.Unlock()
+
+	if ok && len(node.Addresses) > 0 {
+		pkt := discover.AnnounceV1{
+			Magic:  discover.AnnouncementMagicV1,
+			NodeID: pkt.NodeID,
+			Port:   node.Addresses[0].Port,
+			IP:     node.Addresses[0].IP,
+		}
+		if debug {
+			log.Printf("-> %v %#v", addr, pkt)
+		}
+
+		tb := pkt.MarshalXDR()
+		_, _, err = conn.WriteMsgUDP(tb, nil, addr)
+		if err != nil {
+			log.Println("QueryV1 response write:", err)
+		}
+
+		lock.Lock()
+		answered++
+		lock.Unlock()
+	}
+}
+
+func handleAnnounceV2(addr *net.UDPAddr, buf []byte) {
+	var pkt discover.AnnounceV2
+	err := pkt.UnmarshalXDR(buf)
+	if err != nil {
+		log.Println("AnnounceV2 Unmarshal:", err)
+		log.Println(hex.Dump(buf))
+		return
+	}
+	if debug {
+		log.Printf("<- %v %#v", addr, pkt)
+	}
+
+	ip := addr.IP.To4()
+	if ip == nil {
+		ip = addr.IP.To16()
+	}
+
+	var addrs []Address
+	for _, addr := range pkt.Addresses {
+		tip := addr.IP
+		if len(tip) == 0 {
+			tip = ip
+		}
+		addrs = append(addrs, Address{
+			IP:   tip,
+			Port: addr.Port,
+		})
+	}
+
+	node := Node{
+		Addresses: addrs,
+		Updated:   time.Now(),
+	}
+
+	lock.Lock()
+	nodes[pkt.NodeID] = node
+	lock.Unlock()
+}
+
+func handleQueryV2(conn *net.UDPConn, addr *net.UDPAddr, buf []byte) {
+	var pkt discover.QueryV2
+	err := pkt.UnmarshalXDR(buf)
+	if err != nil {
+		log.Println("QueryV2 Unmarshal:", err)
+		log.Println(hex.Dump(buf))
+		return
+	}
+	if debug {
+		log.Printf("<- %v %#v", addr, pkt)
+	}
+
+	lock.Lock()
+	node, ok := nodes[pkt.NodeID]
+	queries++
+	lock.Unlock()
+
+	if ok && len(node.Addresses) > 0 {
+		pkt := discover.AnnounceV2{
+			Magic:  discover.AnnouncementMagicV2,
+			NodeID: pkt.NodeID,
+		}
+		for _, addr := range node.Addresses {
+			pkt.Addresses = append(pkt.Addresses, discover.Address{IP: addr.IP, Port: addr.Port})
+		}
+		if debug {
+			log.Printf("-> %v %#v", addr, pkt)
+		}
+
+		tb := pkt.MarshalXDR()
+		_, _, err = conn.WriteMsgUDP(tb, nil, addr)
+		if err != nil {
+			log.Println("QueryV2 response write:", err)
+		}
+
+		lock.Lock()
+		answered++
+		lock.Unlock()
+	}
+}
+
+func logStats() {
+	for {
+		time.Sleep(600 * time.Second)
+
+		lock.Lock()
+
+		var deleted = 0
+		for id, node := range nodes {
+			if time.Since(node.Updated) > 60*time.Minute {
+				delete(nodes, id)
+				deleted++
+			}
+		}
+		log.Printf("Expired %d nodes; %d nodes in registry; %d queries (%d answered)", deleted, len(nodes), queries, answered)
+		queries = 0
+		answered = 0
+
+		lock.Unlock()
+	}
+}