feat: implement remapping using direct connection data from the shadowEPS

Author: Gabbe64

pkg/liqo-controller-manager/offloading/shadowendpointslice-controller/mapping.go

@@ -22,21 +22,50 @@ import (
 
 	liqov1beta1 "github.com/liqotech/liqo/apis/core/v1beta1"
 	ipamips "github.com/liqotech/liqo/pkg/utils/ipam/mapping"
+	directconnectioninfo "github.com/liqotech/liqo/pkg/utils/directconnection"
+	klog "k8s.io/klog/v2"
 )
 
 // MapEndpointsWithConfiguration maps the endpoints of the shadowendpointslice.
+//
+// The last parameter is needed to 
 func MapEndpointsWithConfiguration(ctx context.Context, cl client.Client,
-	clusterID liqov1beta1.ClusterID, endpoints []discoveryv1.Endpoint) error {
+	clusterID liqov1beta1.ClusterID, endpoints []discoveryv1.Endpoint,
+	list directconnectioninfo.DirectConnectionInfoList,
+	) error {
 	for i := range endpoints {
 		for j := range endpoints[i].Addresses {
 			addr := endpoints[i].Addresses[j]
 
-			rAddr, err := ipamips.MapAddress(ctx, cl, clusterID, addr)
-			if err != nil {
-				return err
+			addrHasBeenRemapped := false
+
+			// If data is passed, check if mapping can be made manually 
+			if len(list.Items) != 0 {
+				clusterID, ip, addressFound := list.GetConnectionDataByIp(addr)
+				
+				if addressFound {
+					rAddr, err := ipamips.ForceMapAddressWithConfiguration(ctx, cl, liqov1beta1.ClusterID(clusterID), ip)
+
+					if err == nil { 
+						endpoints[i].Addresses[j] = rAddr.String()
+						addrHasBeenRemapped = true
+					} else {
+						klog.Errorf("error while mapping address %q using the cidr from clusterID %q: %v", ip, clusterID, err)
+					}
+				}
+				if addrHasBeenRemapped {
+					break
+				}	
 			}
 
-			endpoints[i].Addresses[j] = rAddr
+			// Regular mapping is performed
+			if !addrHasBeenRemapped {
+				rAddr, err := ipamips.MapAddress(ctx, cl, clusterID, addr)
+				if err != nil {
+					return err
+				}
+				endpoints[i].Addresses[j] = rAddr
+			}
 		}
 	}
 

pkg/liqo-controller-manager/offloading/shadowendpointslice-controller/shadowendpointslice_controller.go

@@ -44,9 +44,14 @@ import (
 	foreigncluster "github.com/liqotech/liqo/pkg/utils/foreigncluster"
 	"github.com/liqotech/liqo/pkg/utils/resource"
 	"github.com/liqotech/liqo/pkg/virtualKubelet/forge"
+
+	directconnectioninfo "github.com/liqotech/liqo/pkg/utils/directconnection"
 )
 
-const ctrlFieldManager = "shadow-endpointslice-controller"
+const (
+	ctrlFieldManager = "shadow-endpointslice-controller"
+	directConnectionAnnotationLabel = "direct-connections-data"
+)
 
 // Reconciler reconciles a ShadowEndpointSlice object.
 type Reconciler struct {
@@ -97,12 +102,24 @@ func (r *Reconciler) Reconcile(ctx context.Context, req ctrl.Request) (ctrl.Resu
 	// Check foreign API server status
 	apiServerReady := foreigncluster.IsAPIServerReadyOrDisabled(fc)
 
+	// Check if direct connections data is provided
+	var remoteConnectionsData directconnectioninfo.DirectConnectionInfoList
+	if val, ok := shadowEps.Annotations[directConnectionAnnotationLabel]; ok {
+		err := remoteConnectionsData.FromJSON([]byte(val))
+
+		if err != nil {
+			klog.Errorf("failed to unmarshal direct connection data for shadowendpointslice %q: %v", nsName, err)
+		}
+		// JSON is not propagated to the EndpointSlice
+		delete(shadowEps.Annotations, directConnectionAnnotationLabel)
+	}
+
 	// Get the endpoints from the shadowendpointslice and remap them if necessary.
 	// If the networking module is disabled, we do not need to remap the endpoints.
 	remappedEndpoints := shadowEps.Spec.Template.Endpoints
 	if foreigncluster.IsNetworkingModuleEnabled(fc) {
 		// remap the endpoints if the network configuration of the remote cluster overlaps with the local one
-		if err := MapEndpointsWithConfiguration(ctx, r.Client, clusterID, remappedEndpoints); err != nil {
+		if err := MapEndpointsWithConfiguration(ctx, r.Client, clusterID, remappedEndpoints, remoteConnectionsData); err != nil {
 			klog.Errorf("an error occurred while remapping endpoints for shadowendpointslice %q: %v", nsName, err)
 			return ctrl.Result{}, err
 		}

pkg/utils/ipam/mapping/ips.go

@@ -174,6 +174,30 @@ func MapAddressWithConfiguration(cfg *networkingv1beta1.Configuration, address s
 	return address, nil
 }
 
+// ForceMapAddressWithConfiguration forces the mapping of the provided address using the podCIDR of the remote cluster, retrieved using its clusterID.
+//
+// In case of failure returns the address unchanged.
+func ForceMapAddressWithConfiguration(ctx context.Context, cl client.Client,
+	clusterID liqov1beta1.ClusterID, address string,
+	) (net.IP, error) {
+
+	// This address is used only to get the host part!
+	addr := net.ParseIP(address)
+
+	cfg, err := getters.GetConfigurationByClusterID(ctx, cl, clusterID, corev1.NamespaceAll)
+	if err != nil {
+		return addr, err
+	}
+
+	podCidr := cidrutils.GetPrimary(cfg.Status.Remote.CIDR.Pod).String()
+	_, podnet, err := net.ParseCIDR(podCidr)
+	if err != nil {
+		return addr, err
+	}
+
+	return RemapMask(addr, *podnet), nil
+}
+
 // RemapMask take an IP address and a network mask and remap the address to the network.
 // This means that the host part of the address is preserved, while the network part is replaced with the one in the mask.
 //