fix goroutine leak and reduce code duplication

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

arp_darwin.go

@@ -45,7 +45,7 @@ func (t *Tendrils) parseARPTable() []arpEntry {
 		macStr = normalizeMACAddress(macStr)
 		mac, err := net.ParseMAC(macStr)
 		if err != nil {
-			log.Printf("[arp] failed to parse MAC %q for IP %s: %v", macStr, ipStr, err)
+			log.Printf("[ERROR] [arp] failed to parse MAC %q for IP %s: %v", macStr, ipStr, err)
 			continue
 		}
 

artnet.go

@@ -30,18 +30,7 @@ type ArtNetNode struct {
 }
 
 func (t *Tendrils) listenArtNet(ctx context.Context, iface net.Interface) {
-	addrs, err := iface.Addrs()
+	srcIP, _ := getInterfaceIPv4(iface)
-	if err != nil {
-		return
-	}
-
-	var srcIP net.IP
-	for _, addr := range addrs {
-		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
-			srcIP = ipnet.IP.To4()
-			break
-		}
-	}
 	if srcIP == nil {
 		return
 	}
@@ -157,23 +146,7 @@ func (t *Tendrils) handleArtPollReply(ifaceName string, srcIP net.IP, data []byt
 }
 
 func (t *Tendrils) runArtNetPoller(ctx context.Context, iface net.Interface, conn *net.UDPConn) {
-	addrs, err := iface.Addrs()
+	_, broadcast := getInterfaceIPv4(iface)
-	if err != nil {
-		return
-	}
-
-	var broadcast net.IP
-	for _, addr := range addrs {
-		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
-			ip := ipnet.IP.To4()
-			mask := ipnet.Mask
-			broadcast = make(net.IP, 4)
-			for i := 0; i < 4; i++ {
-				broadcast[i] = ip[i] | ^mask[i]
-			}
-			break
-		}
-	}
 	if broadcast == nil {
 		return
 	}

bmd.go

@@ -14,24 +14,7 @@ func (t *Tendrils) listenBMD(ctx context.Context, iface net.Interface) {
 }
 
 func (t *Tendrils) discoverATEMs(ctx context.Context, iface net.Interface) {
-	addrs, err := iface.Addrs()
+	srcIP, broadcast := getInterfaceIPv4(iface)
-	if err != nil {
-		return
-	}
-
-	var srcIP net.IP
-	var broadcast net.IP
-	for _, addr := range addrs {
-		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
-			srcIP = ipnet.IP.To4()
-			mask := ipnet.Mask
-			broadcast = make(net.IP, 4)
-			for i := 0; i < 4; i++ {
-				broadcast[i] = srcIP[i] | ^mask[i]
-			}
-			break
-		}
-	}
 	if srcIP == nil {
 		return
 	}

dante.go

@@ -140,6 +140,15 @@ func NewDanteFlows() *DanteFlows {
 	}
 }
 
+func containsString(slice []string, val string) bool {
+	for _, s := range slice {
+		if s == val {
+			return true
+		}
+	}
+	return false
+}
+
 func (d *DanteFlows) Update(source, subscriber *Node, channelInfo string) {
 	d.mu.Lock()
 	defer d.mu.Unlock()
@@ -161,18 +170,9 @@ func (d *DanteFlows) Update(source, subscriber *Node, channelInfo string) {
 		flow.Subscribers[subscriber] = sub
 	}
 
-	if channelInfo != "" {
+	if channelInfo != "" && !containsString(sub.Channels, channelInfo) {
-		hasChannel := false
+		sub.Channels = append(sub.Channels, channelInfo)
-		for _, ch := range sub.Channels {
+		sort.Strings(sub.Channels)
-			if ch == channelInfo {
-				hasChannel = true
-				break
-			}
-		}
-		if !hasChannel {
-			sub.Channels = append(sub.Channels, channelInfo)
-			sort.Strings(sub.Channels)
-		}
 	}
 
 	sub.LastSeen = time.Now()
@@ -188,14 +188,7 @@ func (d *DanteFlows) ReplaceNode(oldNode, newNode *Node) {
 			for subNode, sub := range flow.Subscribers {
 				if existingSub, hasSub := existingFlow.Subscribers[subNode]; hasSub {
 					for _, ch := range sub.Channels {
-						hasChannel := false
+						if !containsString(existingSub.Channels, ch) {
-						for _, existingCh := range existingSub.Channels {
-							if existingCh == ch {
-								hasChannel = true
-								break
-							}
-						}
-						if !hasChannel {
 							existingSub.Channels = append(existingSub.Channels, ch)
 						}
 					}
@@ -214,14 +207,7 @@ func (d *DanteFlows) ReplaceNode(oldNode, newNode *Node) {
 			delete(flow.Subscribers, oldNode)
 			if existingSub, hasNew := flow.Subscribers[newNode]; hasNew {
 				for _, ch := range sub.Channels {
-					hasChannel := false
+					if !containsString(existingSub.Channels, ch) {
-					for _, existingCh := range existingSub.Channels {
-						if existingCh == ch {
-							hasChannel = true
-							break
-						}
-					}
-					if !hasChannel {
 						existingSub.Channels = append(existingSub.Channels, ch)
 					}
 				}

igmp.go

@@ -111,18 +111,7 @@ func (t *Tendrils) handleIGMPv3(ifaceName string, sourceIP net.IP, igmp *layers.
 }
 
 func (t *Tendrils) runIGMPQuerier(ctx context.Context, iface net.Interface) {
-	addrs, err := iface.Addrs()
+	srcIP, _ := getInterfaceIPv4(iface)
-	if err != nil {
-		return
-	}
-
-	var srcIP net.IP
-	for _, addr := range addrs {
-		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
-			srcIP = ipnet.IP.To4()
-			break
-		}
-	}
 	if srcIP == nil {
 		return
 	}

nodes.go

@@ -83,18 +83,7 @@ func (s *InterfaceStats) String() string {
 		}
 	}
 
-	return "[" + fmt.Sprintf("%s", joinParts(parts)) + "]"
+	return "[" + strings.Join(parts, " ") + "]"
-}
-
-func joinParts(parts []string) string {
-	result := ""
-	for i, p := range parts {
-		if i > 0 {
-			result += " "
-		}
-		result += p
-	}
-	return result
 }
 
 type PoEBudget struct {
@@ -133,7 +122,7 @@ func (n *Node) String() string {
 
 	parts = append(parts, fmt.Sprintf("{%v}", ifaces))
 
-	return joinParts(parts)
+	return strings.Join(parts, " ")
 }
 
 func (n *Node) DisplayName() string {
@@ -541,8 +530,10 @@ func (n *Nodes) mergeNodes(keepID, mergeID int) {
 		for _, ip := range iface.IPs {
 			ips = append(ips, ip)
 		}
-		n.updateNodeInterface(keep, keepID, iface.MAC, ips, iface.Name)
+		if iface.MAC != nil {
-		n.macIndex[iface.MAC.String()] = keepID
+			n.updateNodeInterface(keep, keepID, iface.MAC, ips, iface.Name)
+			n.macIndex[iface.MAC.String()] = keepID
+		}
 	}
 
 	for peerMAC, ifaceName := range merge.MACTable {
@@ -563,6 +554,11 @@ func (n *Nodes) mergeNodes(keepID, mergeID int) {
 		}
 	}
 
+	if cancel, exists := n.nodeCancel[mergeID]; exists {
+		cancel()
+		delete(n.nodeCancel, mergeID)
+	}
+
 	delete(n.nodes, mergeID)
 }
 
@@ -747,7 +743,7 @@ func (n *Nodes) logNode(node *Node) {
 		tags = append(tags, "dante-clock-master")
 	}
 	if len(tags) > 0 {
-		log.Printf("[node] %s [%s]", name, joinParts(tags))
+		log.Printf("[node] %s [%s]", name, strings.Join(tags, " "))
 	} else {
 		log.Printf("[node] %s", name)
 	}
@@ -911,7 +907,9 @@ func (n *Nodes) getDirectLinks() []*Link {
 	macToNode := map[string]*Node{}
 	for _, node := range n.nodes {
 		for _, iface := range node.Interfaces {
-			macToNode[iface.MAC.String()] = node
+			if iface.MAC != nil {
+				macToNode[iface.MAC.String()] = node
+			}
 		}
 	}
 
@@ -921,6 +919,9 @@ func (n *Nodes) getDirectLinks() []*Link {
 	for _, target := range n.nodes {
 		seenMACs := map[string]bool{}
 		for _, iface := range target.Interfaces {
+			if iface.MAC == nil {
+				continue
+			}
 			mac := iface.MAC.String()
 			if seenMACs[mac] {
 				continue

snmp.go

@@ -51,6 +51,21 @@ func defaultSNMPConfig() *snmpConfig {
 	}
 }
 
+func snmpToInt(val interface{}) (int, bool) {
+	switch v := val.(type) {
+	case int:
+		return v, true
+	case uint:
+		return int(v), true
+	case int64:
+		return int(v), true
+	case uint64:
+		return int(v), true
+	default:
+		return 0, false
+	}
+}
+
 func (t *Tendrils) connectSNMP(ip net.IP) (*gosnmp.GoSNMP, error) {
 	cfg := defaultSNMPConfig()
 
@@ -89,11 +104,13 @@ func (t *Tendrils) querySNMPDevice(node *Node, ip net.IP) {
 	}
 	defer snmp.Conn.Close()
 
+	ifNames := t.getInterfaceNames(snmp)
+
 	t.querySysName(snmp, node)
-	t.queryInterfaceMACs(snmp, node)
+	t.queryInterfaceMACs(snmp, node, ifNames)
-	t.queryInterfaceStats(snmp, node)
+	t.queryInterfaceStats(snmp, node, ifNames)
 	t.queryPoEBudget(snmp, node)
-	t.queryBridgeMIB(snmp, node)
+	t.queryBridgeMIB(snmp, node, ifNames)
 }
 
 func (t *Tendrils) querySysName(snmp *gosnmp.GoSNMP, node *Node) {
@@ -121,7 +138,7 @@ func (t *Tendrils) querySysName(snmp *gosnmp.GoSNMP, node *Node) {
 	t.nodes.Update(node, nil, nil, "", sysName, "snmp-sysname")
 }
 
-func (t *Tendrils) queryInterfaceMACs(snmp *gosnmp.GoSNMP, node *Node) {
+func (t *Tendrils) queryInterfaceMACs(snmp *gosnmp.GoSNMP, node *Node, ifNames map[int]string) {
 	oid := "1.3.6.1.2.1.2.2.1.6"
 
 	results, err := snmp.BulkWalkAll(oid)
@@ -129,8 +146,6 @@ func (t *Tendrils) queryInterfaceMACs(snmp *gosnmp.GoSNMP, node *Node) {
 		return
 	}
 
-	ifNames := t.getInterfaceNames(snmp)
-
 	for _, result := range results {
 		if result.Type != gosnmp.OctetString {
 			continue
@@ -161,9 +176,7 @@ func (t *Tendrils) queryInterfaceMACs(snmp *gosnmp.GoSNMP, node *Node) {
 	}
 }
 
-func (t *Tendrils) queryInterfaceStats(snmp *gosnmp.GoSNMP, node *Node) {
+func (t *Tendrils) queryInterfaceStats(snmp *gosnmp.GoSNMP, node *Node, ifNames map[int]string) {
-	ifNames := t.getInterfaceNames(snmp)
-
 	ifOperStatus := t.getInterfaceTable(snmp, "1.3.6.1.2.1.2.2.1.8")
 	ifHighSpeed := t.getInterfaceTable(snmp, "1.3.6.1.2.1.31.1.1.1.15")
 	ifInErrors := t.getInterfaceTable(snmp, "1.3.6.1.2.1.2.2.1.14")
@@ -221,20 +234,10 @@ func (t *Tendrils) queryPoEBudget(snmp *gosnmp.GoSNMP, node *Node) {
 
 	var power, maxPower float64
 	for _, v := range result.Variables {
-		var val int
+		val, ok := snmpToInt(v.Value)
-		switch x := v.Value.(type) {
+		if !ok {
-		case int:
-			val = x
-		case uint:
-			val = int(x)
-		case int64:
-			val = int(x)
-		case uint64:
-			val = int(x)
-		default:
 			continue
 		}
-
 		if v.Name == "."+powerOID {
 			power = float64(val)
 		} else if v.Name == "."+maxPowerOID {
@@ -263,20 +266,10 @@ func (t *Tendrils) getInterfaceTable(snmp *gosnmp.GoSNMP, oid string) map[int]in
 			continue
 		}
 
-		var value int
+		value, ok := snmpToInt(result.Value)
-		switch v := result.Value.(type) {
+		if !ok {
-		case int:
-			value = v
-		case uint:
-			value = int(v)
-		case int64:
-			value = int(v)
-		case uint64:
-			value = int(v)
-		default:
 			continue
 		}
-
 		table[ifIndex] = value
 	}
 	return table
@@ -306,17 +299,8 @@ func (t *Tendrils) getPoEStats(snmp *gosnmp.GoSNMP, ifNames map[int]string) map[
 			continue
 		}
 
-		var status int
+		status, ok := snmpToInt(result.Value)
-		switch v := result.Value.(type) {
+		if !ok {
-		case int:
-			status = v
-		case uint:
-			status = int(v)
-		case int64:
-			status = int(v)
-		case uint64:
-			status = int(v)
-		default:
 			continue
 		}
 
@@ -367,26 +351,16 @@ func (t *Tendrils) getPoETable(snmp *gosnmp.GoSNMP, oid string) map[int]int {
 			continue
 		}
 
-		var value int
+		value, ok := snmpToInt(result.Value)
-		switch v := result.Value.(type) {
+		if !ok {
-		case int:
-			value = v
-		case uint:
-			value = int(v)
-		case int64:
-			value = int(v)
-		case uint64:
-			value = int(v)
-		default:
 			continue
 		}
-
 		table[portIndex] = value
 	}
 	return table
 }
 
-func (t *Tendrils) queryBridgeMIB(snmp *gosnmp.GoSNMP, node *Node) {
+func (t *Tendrils) queryBridgeMIB(snmp *gosnmp.GoSNMP, node *Node, ifNames map[int]string) {
 	portOID := "1.3.6.1.2.1.17.7.1.2.2.1.2"
 
 	portResults, err := snmp.BulkWalkAll(portOID)
@@ -423,7 +397,6 @@ func (t *Tendrils) queryBridgeMIB(snmp *gosnmp.GoSNMP, node *Node) {
 	}
 
 	bridgePortToIfIndex := t.getBridgePortMapping(snmp)
-	ifNames := t.getInterfaceNames(snmp)
 
 	for _, entry := range macPorts {
 		mac := entry.mac

tendrils.go

@@ -10,6 +10,25 @@ import (
 	"time"
 )
 
+func getInterfaceIPv4(iface net.Interface) (srcIP, broadcast net.IP) {
+	addrs, err := iface.Addrs()
+	if err != nil {
+		return nil, nil
+	}
+	for _, addr := range addrs {
+		if ipnet, ok := addr.(*net.IPNet); ok && ipnet.IP.To4() != nil {
+			srcIP = ipnet.IP.To4()
+			mask := ipnet.Mask
+			broadcast = make(net.IP, 4)
+			for i := 0; i < 4; i++ {
+				broadcast[i] = srcIP[i] | ^mask[i]
+			}
+			return srcIP, broadcast
+		}
+	}
+	return nil, nil
+}
+
 type Tendrils struct {
 	activeInterfaces map[string]context.CancelFunc
 	nodes            *Nodes