Merge pull request #18049 from danwinship/egress-ip-setup-fix

Automatic merge from submit-queue (batch tested with PRs 18117, 18049).

Make sure oc.tunMAC gets set even if AlreadySetUp()

Noticed while trying to fix rhbz 1527642: oc.tunMAC currently only gets set from SetupOVS(), so if you restart OpenShift and SDN setup gets skipped, then tunMAC will be unset, and so new auto-egress-ip rules will fail.

The switch from using netlink to use ovs-vsctl to fetch the MAC is because an earlier version of the patch broke the hack in ovscontroller_test.go that manually sets tunMAC, and made it so that SetupOVS would always have to read tunMAC from tun0. But calling netlink wouldn't work from ovscontroller_test, so I rewrote it to use ovs-vsctl to get the MAC instead, since that was mockable. But then I ended up rewriting things so that it was possible for ovscontroller_test to still just manually override it anyway. But I liked the ovs-vsctl-rather-than-netlink approach because it makes ovsController more self-contained and mock-able so I kept it.

pkg/network/node/ovscontroller.go

@@ -18,8 +18,6 @@ import (
 
 	"k8s.io/apimachinery/pkg/util/sets"
 	kapi "k8s.io/kubernetes/pkg/apis/core"
-
-	"github.com/vishvananda/netlink"
 )
 
 type ovsController struct {
@@ -87,13 +85,6 @@ func (oc *ovsController) SetupOVS(clusterNetworkCIDR []string, serviceNetworkCID
 	if err != nil {
 		return err
 	}
-	if oc.tunMAC == "" {
-		link, err := netlink.LinkByName(Tun0)
-		if err != nil {
-			return err
-		}
-		oc.tunMAC = link.Attrs().HardwareAddr.String()
-	}
 
 	otx := oc.ovs.NewTransaction()
 
@@ -675,6 +666,21 @@ func (oc *ovsController) FindUnusedVNIDs() []int {
 	return policyVNIDs.Difference(inUseVNIDs).UnsortedList()
 }
 
+func (oc *ovsController) ensureTunMAC() error {
+	if oc.tunMAC != "" {
+		return nil
+	}
+
+	val, err := oc.ovs.Get("Interface", Tun0, "mac_in_use")
+	if err != nil {
+		return fmt.Errorf("could not get %s MAC address: %v", Tun0, err)
+	} else if len(val) != 19 || val[0] != '"' || val[18] != '"' {
+		return fmt.Errorf("bad MAC address for %s: %q", Tun0, val)
+	}
+	oc.tunMAC = val[1:18]
+	return nil
+}
+
 func (oc *ovsController) UpdateNamespaceEgressRules(vnid uint32, nodeIP, egressHex string) error {
 	otx := oc.ovs.NewTransaction()
 	otx.DeleteFlows("table=100, reg0=%d", vnid)
@@ -686,6 +692,9 @@ func (oc *ovsController) UpdateNamespaceEgressRules(vnid uint32, nodeIP, egressH
 		otx.AddFlow("table=100, priority=100, reg0=%d, actions=drop", vnid)
 	} else if nodeIP == oc.localIP {
 		// Local Egress IP
+		if err := oc.ensureTunMAC(); err != nil {
+			return err
+		}
 		otx.AddFlow("table=100, priority=100, reg0=%d, ip, actions=set_field:%s->eth_dst,set_field:%s->pkt_mark,goto_table:101", vnid, oc.tunMAC, egressHex)
 	} else {
 		// Remote Egress IP; send via VXLAN