fix local address population and snmp reverse port discovery

populate root node with local macs/ips at startup, excluding loopback addresses and permanent arp entries. detect when snmp finds parent node mac in child forwarding table and set child localport.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

snmp.go

@@ -207,6 +207,30 @@ func (t *Tendrils) queryBridgeMIB(snmp *gosnmp.GoSNMP, deviceIP net.IP) {
 		if addToParent {
 			t.nodes.Update([]net.IP{deviceIP}, []net.HardwareAddr{mac}, "", "", "snmp")
 		} else {
+			t.nodes.mu.RLock()
+			deviceNodeID := -1
+			if id, exists := t.nodes.ipIndex[deviceIP.String()]; exists {
+				deviceNodeID = id
+			}
+			macNodeID := -1
+			if id, exists := t.nodes.macIndex[mac.String()]; exists {
+				macNodeID = id
+			}
+
+			if deviceNodeID != -1 && macNodeID != -1 {
+				deviceNode := t.nodes.nodes[deviceNodeID]
+				if deviceNode.ParentID == macNodeID {
+					t.nodes.mu.RUnlock()
+					t.nodes.mu.Lock()
+					if deviceNode.LocalPort == "" {
+						deviceNode.LocalPort = ifName
+					}
+					t.nodes.mu.Unlock()
+					continue
+				}
+			}
+			t.nodes.mu.RUnlock()
+
 			t.nodes.UpdateWithParent(deviceIP, nil, []net.HardwareAddr{mac}, ifName, "", "snmp")
 		}
 	}
@@ -280,6 +304,30 @@ func (t *Tendrils) queryARPTable(snmp *gosnmp.GoSNMP, deviceIP net.IP) {
 				ifName = "??"
 			}
 
+			t.nodes.mu.RLock()
+			deviceNodeID := -1
+			if id, exists := t.nodes.ipIndex[deviceIP.String()]; exists {
+				deviceNodeID = id
+			}
+			macNodeID := -1
+			if id, exists := t.nodes.macIndex[mac.String()]; exists {
+				macNodeID = id
+			}
+
+			if deviceNodeID != -1 && macNodeID != -1 {
+				deviceNode := t.nodes.nodes[deviceNodeID]
+				if deviceNode.ParentID == macNodeID {
+					t.nodes.mu.RUnlock()
+					t.nodes.mu.Lock()
+					if deviceNode.LocalPort == "" {
+						deviceNode.LocalPort = ifName
+					}
+					t.nodes.mu.Unlock()
+					continue
+				}
+			}
+			t.nodes.mu.RUnlock()
+
 			t.nodes.UpdateWithParent(deviceIP, ips, []net.HardwareAddr{mac}, ifName, "", "snmp")
 		}
 	}