Reduce network environment update overhead

route/network.go

@@ -291,7 +291,7 @@ func (r *NetworkManager) InterfaceFinder() control.InterfaceFinder {
 }
 
 func (r *NetworkManager) UpdateInterfaces() error {
-	defer r.updateNetworkEnvironment()
+	defer r.postUpdateNetworkEnvironment()
 	if r.platformInterface == nil || !r.platformInterface.UsePlatformNetworkInterfaces() {
 		return r.interfaceFinder.Update()
 	} else {

route/network_environment_darwin.go

@@ -10,7 +10,7 @@ import (
 )
 
 func systemGateways(interfaceIndex int) []netip.Addr {
-	rib, err := route.FetchRIB(unix.AF_UNSPEC, route.RIBTypeRoute, 0)
+	rib, err := route.FetchRIB(unix.AF_UNSPEC, route.RIBType(unix.NET_RT_FLAGS), unix.RTF_GATEWAY)
 	if err != nil {
 		return nil
 	}