userspace proxy: get local addresses only once per sync loop

This avoids fetching all local network interfaces everytime we sync an
external IP. For clusters with many external IPs this gets really
expensive. This change caches all local addresses once per sync.

Signed-off-by: Andrew Sy Kim <[email protected]>

Author: andrewsykim

pkg/proxy/userspace/proxier.go

@@ -127,6 +127,7 @@ type Proxier struct {
 	listenIP        net.IP
 	iptables        iptables.Interface
 	hostIP          net.IP
+	localAddrs      []net.IP
 	proxyPorts      PortAllocator
 	makeProxySocket ProxySocketFunc
 	exec            utilexec.Interface
@@ -371,6 +372,14 @@ func (proxier *Proxier) syncProxyRules() {
 		proxier.unmergeService(change.previous, existingPorts)
 	}
 
+	localAddrs, err := utilproxy.GetLocalAddrs()
+	if err != nil {
+		klog.Errorf("Failed to get local addresses during proxy sync: %s, assuming IPs are not local", err)
+	} else if len(localAddrs) == 0 {
+		klog.Warning("No local addresses were found, assuming all external IPs are not local")
+	}
+	proxier.localAddrs = localAddrs
+
 	proxier.ensurePortals()
 	proxier.cleanupStaleStickySessions()
 }
@@ -725,9 +734,7 @@ func (proxier *Proxier) openPortal(service proxy.ServicePortName, info *ServiceI
 }
 
 func (proxier *Proxier) openOnePortal(portal portal, protocol v1.Protocol, proxyIP net.IP, proxyPort int, name proxy.ServicePortName) error {
-	if local, err := utilproxy.IsLocalIP(portal.ip.String()); err != nil {
-		return fmt.Errorf("can't determine if IP %s is local, assuming not: %v", portal.ip, err)
-	} else if local {
+	if len(proxier.localAddrs) > 0 && utilproxy.ContainsIP(proxier.localAddrs, portal.ip) {
 		err := proxier.claimNodePort(portal.ip, portal.port, protocol, name)
 		if err != nil {
 			return err
@@ -903,10 +910,7 @@ func (proxier *Proxier) closePortal(service proxy.ServicePortName, info *Service
 
 func (proxier *Proxier) closeOnePortal(portal portal, protocol v1.Protocol, proxyIP net.IP, proxyPort int, name proxy.ServicePortName) []error {
 	el := []error{}
-
-	if local, err := utilproxy.IsLocalIP(portal.ip.String()); err != nil {
-		el = append(el, fmt.Errorf("can't determine if IP %s is local, assuming not: %v", portal.ip, err))
-	} else if local {
+	if len(proxier.localAddrs) > 0 && utilproxy.ContainsIP(proxier.localAddrs, portal.ip) {
 		if err := proxier.releaseNodePort(portal.ip, portal.port, protocol, name); err != nil {
 			el = append(el, err)
 		}