Merge pull request kubevirt#846 from mlsorensen/filter-gateway-dst-route

Filter pod route destined to default gateway
Ethan-2017 · Mar 28, 2018 · aed5d0d · aed5d0d
2 parents 9823b02 + c5c69d0
commit aed5d0d
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Showing 3 changed files with 46 additions and 13 deletions.
diff --git a/pkg/virt-launcher/virtwrap/network/dhcp/dhcp.go b/pkg/virt-launcher/virtwrap/network/dhcp/dhcp.go
@@ -45,18 +45,24 @@ func SingleClientDHCPServer(
 
 	log.Log.Info("Starting SingleClientDHCPServer")
 
+	dhcpOptions := dhcp.Options{
+		dhcp.OptionSubnetMask:       []byte(clientMask),
+		dhcp.OptionRouter:           []byte(routerIP),
+		dhcp.OptionDomainNameServer: bytes.Join(dnsIPs, nil),
+	}
+
 	netRoutes := FormClasslessRoutes(routes, routerIP)
+
+	if netRoutes != nil {
+		dhcpOptions[dhcp.OptionClasslessRouteFormat] = netRoutes
+	}
+
 	handler := &DHCPHandler{
 		clientIP:      clientIP,
 		clientMAC:     clientMAC,
 		serverIP:      serverIP.To4(),
 		leaseDuration: infiniteLease,
-		options: dhcp.Options{
-			dhcp.OptionSubnetMask:           []byte(clientMask),
-			dhcp.OptionRouter:               []byte(routerIP),
-			dhcp.OptionDomainNameServer:     bytes.Join(dnsIPs, nil),
-			dhcp.OptionClasslessRouteFormat: netRoutes,
-		},
+		options:       dhcpOptions,
 	}
 
 	l, err := dhcpConn.NewUDP4BoundListener(serverIface, ":67")

diff --git a/pkg/virt-launcher/virtwrap/network/network.go b/pkg/virt-launcher/virtwrap/network/network.go
@@ -333,14 +333,8 @@ func discoverPodNetworkInterface(nic *VIF) (netlink.Link, error) {
 		return nil, fmt.Errorf("No gateway address found in routes for %s", podInterface)
 	}
 	nic.Gateway = routes[0].Gw
-	var dhcpRoutes []netlink.Route
 	if len(routes) > 1 {
-		// Filter out irrelevant routes
-		for _, route := range routes[1:] {
-			if !route.Src.Equal(nic.IP.IP) {
-				dhcpRoutes = append(dhcpRoutes, route)
-			}
-		}
+		dhcpRoutes := filterPodNetworkRoutes(routes, nic)
 		nic.Routes = &dhcpRoutes
 	}
 
@@ -354,6 +348,24 @@ func discoverPodNetworkInterface(nic *VIF) (netlink.Link, error) {
 	return nicLink, nil
 }
 
+// filter out irrelevant routes
+func filterPodNetworkRoutes(routes []netlink.Route, nic *VIF) (filteredRoutes []netlink.Route) {
+	for _, route := range routes[1:] {
+		// don't create static route to default gateway
+		if route.Dst != nil && route.Dst.IP.Equal(nic.Gateway) && route.Src.Equal(nil) {
+			continue
+		}
+
+		// don't create static route for src == nic
+		if route.Src != nil && route.Src.Equal(nic.IP.IP) {
+			continue
+		}
+
+		filteredRoutes = append(filteredRoutes, route)
+	}
+	return
+}
+
 func preparePodNetworkInterfaces(nic *VIF, nicLink netlink.Link) error {
 	// Remove IP from POD interface
 	err := Handler.AddrDel(nicLink, &nic.IP)

diff --git a/pkg/virt-launcher/virtwrap/network/network_test.go b/pkg/virt-launcher/virtwrap/network/network_test.go
@@ -148,6 +148,21 @@ var _ = Describe("Network", func() {
 		})
 	})
 
+	Context("func filterPodNetworkRoutes()", func() {
+		staticRoute := netlink.Route{
+			Dst: &net.IPNet{IP: net.IPv4(10, 45, 0, 10), Mask: net.CIDRMask(32, 32)},
+			Gw:  net.IPv4(10, 25, 0, 1),
+		}
+		gwRoute := netlink.Route{Dst: &net.IPNet{IP: net.IPv4(10, 35, 0, 1), Mask: net.CIDRMask(32, 32)}}
+		nicRoute := netlink.Route{Src: net.IPv4(10, 35, 0, 6)}
+		staticRouteList := []netlink.Route{routeAddr, gwRoute, nicRoute, staticRoute}
+
+		It("should remove default gateway and source IP from routes, leaving others intact", func() {
+			expected := []netlink.Route{staticRoute}
+			Expect(filterPodNetworkRoutes(staticRouteList, testNic)).To(Equal(expected))
+		})
+	})
+
 	Context("Function ParseNameservers()", func() {
 		It("should return a byte array of nameservers", func() {
 			ns1, ns2 := []uint8{8, 8, 8, 8}, []uint8{8, 8, 4, 4}