added vxlan overlay network and test suite

pkg/liqonet/overlay/overlay_suite_test.go

@@ -0,0 +1,70 @@
+package overlay
+
+import (
+	"net"
+	"testing"
+
+	"github.com/vishvananda/netlink"
+
+	"github.com/liqotech/liqo/pkg/liqonet"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var (
+	defaultIfaceIP net.IP
+)
+
+func TestOverlay(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Overlay Suite")
+}
+
+var _ = BeforeSuite(func() {
+	var err error
+	defaultIfaceIP, err = getIFaceIP("0.0.0.0")
+	Expect(err).ShouldNot(HaveOccurred())
+	Expect(defaultIfaceIP).ShouldNot(BeNil())
+	// Create dummy link
+	err = netlink.LinkAdd(&netlink.Dummy{LinkAttrs: netlink.LinkAttrs{Name: "dummy-link"}})
+	Expect(err).ShouldNot(HaveOccurred())
+})
+
+/*var _ = AfterSuite(func() {
+
+})*/
+
+func getIFaceIP(ipAddress string) (net.IP, error) {
+	var ifaceIndex int
+	// Convert the given IP address from string to net.IP format
+	ip := net.ParseIP(ipAddress)
+	if ip == nil {
+		return nil, &liqonet.ParseIPError{
+			IPToBeParsed: ipAddress,
+		}
+	}
+	routes, err := netlink.RouteList(nil, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, err
+	}
+	// Find the route whose destination contains our IP address.
+	for i := range routes {
+		if routes[i].Scope == netlink.SCOPE_UNIVERSE {
+			ifaceIndex = routes[i].LinkIndex
+		}
+	}
+	if ifaceIndex == 0 {
+		return nil, &liqonet.NoRouteFound{IPAddress: ipAddress}
+	}
+	// Get link.
+	link, err := netlink.LinkByIndex(ifaceIndex)
+	if err != nil {
+		return nil, err
+	}
+	ips, err := netlink.AddrList(link, netlink.FAMILY_V4)
+	if err != nil {
+		return nil, err
+	}
+	return ips[0].IP, nil
+}

pkg/liqonet/overlay/vxlan.go

@@ -0,0 +1,153 @@
+package overlay
+
+import (
+	"fmt"
+	"net"
+	"reflect"
+	"syscall"
+
+	"github.com/vishvananda/netlink"
+	"golang.org/x/sys/unix"
+	"k8s.io/klog/v2"
+)
+
+// VxlanDeviceAttrs configuration for a new vxlan device.
+type VxlanDeviceAttrs struct {
+	Vni      int
+	Name     string
+	VtepPort int
+	VtepAddr net.IP
+	Mtu      int
+}
+
+// VxlanDevice struct that holds a vxlan link.
+type VxlanDevice struct {
+	Link *netlink.Vxlan
+}
+
+// Neighbor struct that holds information for an fdb entry.
+type Neighbor struct {
+	MAC net.HardwareAddr
+	IP  net.IP
+}
+
+// NewVxlanDevice takes as argument a struct of type VxlanDeviceAttrs and returns a VxlanDevice or error.
+func NewVxlanDevice(devAttrs *VxlanDeviceAttrs) (*VxlanDevice, error) {
+	link := &netlink.Vxlan{
+		LinkAttrs: netlink.LinkAttrs{
+			Name:  devAttrs.Name,
+			MTU:   devAttrs.Mtu,
+			Flags: net.FlagUp,
+		},
+		VxlanId:  devAttrs.Vni,
+		SrcAddr:  devAttrs.VtepAddr,
+		Port:     devAttrs.VtepPort,
+		Learning: true,
+	}
+
+	link, err := createVxLanLink(link)
+	if err != nil {
+		return nil, err
+	}
+	return &VxlanDevice{
+		Link: link,
+	}, nil
+}
+
+func createVxLanLink(link *netlink.Vxlan) (*netlink.Vxlan, error) {
+	err := netlink.LinkAdd(link)
+	if err == syscall.EEXIST {
+		existing, err := netlink.LinkByName(link.Name)
+		if err != nil {
+			return nil, fmt.Errorf("failed to retrieve Link with name %s: %v", link.Name, err)
+		}
+		if isVxlanConfigTheSame(link, existing) {
+			klog.V(4).Infof("vxlan device with the same configuration already exists")
+			link = existing.(*netlink.Vxlan)
+			return link, nil
+		}
+		// If we come here it means that the config of the existing vxlan device does not match with the new one.
+		// We delete it and then recreate.
+		if err = netlink.LinkDel(existing); err != nil {
+			return nil, fmt.Errorf("failed to delete the existing vxlan device with name %s: %v", existing.Attrs().Name, err)
+		}
+		if err = netlink.LinkAdd(link); err != nil {
+			return nil, fmt.Errorf("failed to re-create the vxlan interface: %v", err)
+		}
+	} else if err != nil {
+		return nil, fmt.Errorf("failed to create the vxlan interface: %v", err)
+	}
+	ifindex := link.Index
+	vxlan, err := netlink.LinkByIndex(ifindex)
+	if err != nil {
+		return nil, fmt.Errorf("can't locate created vxlan device with index %v, %v", ifindex, err)
+	}
+	return vxlan.(*netlink.Vxlan), nil
+}
+
+// If a vxlan exists with the same name then we use this function to check if the configuration is the same.
+func isVxlanConfigTheSame(new, current netlink.Link) bool {
+	if new.Type() != current.Type() {
+		klog.V(4).Infof("different types for the interfaces: new -> %v, current -> %v", new.Type(), current.Type())
+		return false
+	}
+	newNetlinkVxlan := new.(*netlink.Vxlan)
+	currentNetlinkVxlan := current.(*netlink.Vxlan)
+
+	if newNetlinkVxlan.VxlanId != currentNetlinkVxlan.VxlanId {
+		klog.V(4).Infof("different vxlan ID for the interfaces: new -> %d, current -> %d", newNetlinkVxlan.VxlanId, currentNetlinkVxlan.VxlanId)
+		return false
+	}
+	if !reflect.DeepEqual(newNetlinkVxlan.SrcAddr, currentNetlinkVxlan.SrcAddr) {
+		klog.V(4).Infof("different Source Addresses for the interfaces: new -> %v, current -> %v", newNetlinkVxlan.SrcAddr, currentNetlinkVxlan.SrcAddr)
+		return false
+	}
+	if newNetlinkVxlan.Port != currentNetlinkVxlan.Port {
+		klog.V(4).Infof("different Vxlan Port for the interfaces: new -> %d, current -> %d", newNetlinkVxlan.Port, currentNetlinkVxlan.Port)
+		return false
+	}
+	klog.V(4).Infof("the existing interface is already configured")
+	return true
+}
+
+// AddFDB adds a fdb entry for the given neighbour into the current vxlan device.
+func (vxlan *VxlanDevice) AddFDB(n Neighbor) error {
+	klog.V(4).Infof("calling AppendFDB: %v, %v", n.IP, n.MAC)
+	err := netlink.NeighAdd(&netlink.Neigh{
+		LinkIndex:    vxlan.Link.Index,
+		State:        netlink.NUD_PERMANENT | netlink.NUD_NOARP,
+		Family:       syscall.AF_BRIDGE,
+		Flags:        netlink.NTF_SELF,
+		Type:         netlink.NDA_DST,
+		IP:           n.IP,
+		HardwareAddr: n.MAC,
+	})
+	if err == unix.EEXIST {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+// DelFDB deletes a fdb entry for the given neighbour from the current vxlan device.
+func (vxlan *VxlanDevice) DelFDB(n Neighbor) error {
+	klog.V(4).Infof("calling DelFDB: %v, %v", n.IP, n.MAC)
+	err := netlink.NeighDel(&netlink.Neigh{
+		LinkIndex:    vxlan.Link.Index,
+		State:        netlink.NUD_PERMANENT | netlink.NUD_NOARP,
+		Family:       syscall.AF_BRIDGE,
+		Flags:        netlink.NTF_SELF,
+		Type:         netlink.NDA_DST,
+		IP:           n.IP,
+		HardwareAddr: n.MAC,
+	})
+	if err == unix.ENOENT {
+		return nil
+	}
+	if err != nil {
+		return err
+	}
+	return nil
+}