link: Add support for IFLA_*_COLLECT_METADATA

- Implemented for VXLAN and GRE via a flag `FlowBased`
- Added unit tests to verify ability

Signed-off-by: Thomas Graf <tgraf@tgraf.ch>

link.go

@@ -339,6 +339,7 @@ type Vxlan struct {
 	UDPCSum      bool
 	NoAge        bool
 	GBP          bool
+	FlowBased    bool
 	Age          int
 	Limit        int
 	Port         int
@@ -684,6 +685,7 @@ type Gretap struct {
 	EncapType  uint16
 	EncapFlags uint16
 	Link       uint32
+	FlowBased  bool
 }
 
 func (gretap *Gretap) Attrs() *LinkAttrs {

link_linux.go

@@ -528,7 +528,13 @@ type vxlanPortRange struct {
 
 func addVxlanAttrs(vxlan *Vxlan, linkInfo *nl.RtAttr) {
 	data := nl.NewRtAttrChild(linkInfo, nl.IFLA_INFO_DATA, nil)
+
+	if vxlan.FlowBased {
+		vxlan.VxlanId = 0
+	}
+
 	nl.NewRtAttrChild(data, nl.IFLA_VXLAN_ID, nl.Uint32Attr(uint32(vxlan.VxlanId)))
+
 	if vxlan.VtepDevIndex != 0 {
 		nl.NewRtAttrChild(data, nl.IFLA_VXLAN_LINK, nl.Uint32Attr(uint32(vxlan.VtepDevIndex)))
 	}
@@ -569,6 +575,9 @@ func addVxlanAttrs(vxlan *Vxlan, linkInfo *nl.RtAttr) {
 	if vxlan.GBP {
 		nl.NewRtAttrChild(data, nl.IFLA_VXLAN_GBP, []byte{})
 	}
+	if vxlan.FlowBased {
+		nl.NewRtAttrChild(data, nl.IFLA_VXLAN_FLOWBASED, boolAttr(vxlan.FlowBased))
+	}
 	if vxlan.NoAge {
 		nl.NewRtAttrChild(data, nl.IFLA_VXLAN_AGEING, nl.Uint32Attr(0))
 	} else if vxlan.Age > 0 {
@@ -1407,6 +1416,8 @@ func parseVxlanData(link Link, data []syscall.NetlinkRouteAttr) {
 			vxlan.UDPCSum = int8(datum.Value[0]) != 0
 		case nl.IFLA_VXLAN_GBP:
 			vxlan.GBP = true
+		case nl.IFLA_VXLAN_FLOWBASED:
+			vxlan.FlowBased = int8(datum.Value[0]) != 0
 		case nl.IFLA_VXLAN_AGEING:
 			vxlan.Age = int(native.Uint32(datum.Value[0:4]))
 			vxlan.NoAge = vxlan.Age == 0
@@ -1547,6 +1558,12 @@ func linkFlags(rawFlags uint32) net.Flags {
 func addGretapAttrs(gretap *Gretap, linkInfo *nl.RtAttr) {
 	data := nl.NewRtAttrChild(linkInfo, nl.IFLA_INFO_DATA, nil)
 
+	if gretap.FlowBased {
+		// In flow based mode, no other attributes need to be configured
+		nl.NewRtAttrChild(data, nl.IFLA_GRE_COLLECT_METADATA, boolAttr(gretap.FlowBased))
+		return
+	}
+
 	ip := gretap.Local.To4()
 	if ip != nil {
 		nl.NewRtAttrChild(data, nl.IFLA_GRE_LOCAL, []byte(ip))
@@ -1613,6 +1630,8 @@ func parseGretapData(link Link, data []syscall.NetlinkRouteAttr) {
 			gre.EncapType = native.Uint16(datum.Value[0:2])
 		case nl.IFLA_GRE_ENCAP_FLAGS:
 			gre.EncapFlags = native.Uint16(datum.Value[0:2])
+		case nl.IFLA_GRE_COLLECT_METADATA:
+			gre.FlowBased = int8(datum.Value[0]) != 0
 		}
 	}
 }

link_test.go

@@ -220,6 +220,9 @@ func compareVxlan(t *testing.T, expected, actual *Vxlan) {
 	if actual.GBP != expected.GBP {
 		t.Fatal("Vxlan.GBP doesn't match")
 	}
+	if actual.FlowBased != expected.FlowBased {
+		t.Fatal("Vxlan.FlowBased doesn't match")
+	}
 	if expected.NoAge {
 		if !actual.NoAge {
 			t.Fatal("Vxlan.NoAge doesn't match")
@@ -277,6 +280,19 @@ func TestLinkAddDelGretap(t *testing.T) {
 		Remote:    net.IPv4(127, 0, 0, 1)})
 }
 
+func TestLinkAddDelGretapFlowBased(t *testing.T) {
+	if os.Getenv("TRAVIS_BUILD_DIR") != "" {
+		t.Skipf("Kernel in travis is too old for this test")
+	}
+
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	testLinkAddDel(t, &Gretap{
+		LinkAttrs: LinkAttrs{Name: "foo"},
+		FlowBased: true})
+}
+
 func TestLinkAddDelVlan(t *testing.T) {
 	tearDown := setUpNetlinkTest(t)
 	defer tearDown()
@@ -693,6 +709,25 @@ func TestLinkAddDelVxlanGbp(t *testing.T) {
 	}
 }
 
+func TestLinkAddDelVxlanFlowBased(t *testing.T) {
+	if os.Getenv("TRAVIS_BUILD_DIR") != "" {
+		t.Skipf("Kernel in travis is too old for this test")
+	}
+
+	tearDown := setUpNetlinkTest(t)
+	defer tearDown()
+
+	vxlan := Vxlan{
+		LinkAttrs: LinkAttrs{
+			Name: "foo",
+		},
+		Learning:  false,
+		FlowBased: true,
+	}
+
+	testLinkAddDel(t, &vxlan)
+}
+
 func TestLinkAddDelIPVlanL2(t *testing.T) {
 	if os.Getenv("TRAVIS_BUILD_DIR") != "" {
 		t.Skipf("Kernel in travis is too old for this test")