VIP implementation in TAPA replaced by NSM IP and policy update

* The initial NSM request does not contain any information about the ip
  context. Once the conduit connected (sucessful NSM request), the VIP
  watcher will call SetVIPs which will update (new request) the NSM
  connection (SrcIPs and policies).

* the initial SrcIPs are saved in the conduit struct (to not mix the
  target IPs and VIPs)

* The previous code has been removed

pkg/ambassador/tap/conduit/conduit.go

@@ -20,6 +20,8 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net"
+	"strings"
 	"sync"
 
 	"github.com/networkservicemesh/api/pkg/api/networkservice"
@@ -53,8 +55,7 @@ type Conduit struct {
 	StreamFactory        StreamFactory
 	connection           *networkservice.Connection
 	mu                   sync.Mutex
-	vips                 []*virtualIP
-	tableID              int
+	localIPs             []string
 }
 
 // New is the constructor of Conduit.
@@ -76,8 +77,7 @@ func New(conduit *ambassadorAPI.Conduit,
 		NetworkServiceClient: networkServiceClient,
 		NetUtils:             netUtils,
 		connection:           nil,
-		vips:                 []*virtualIP{},
-		tableID:              1,
+		localIPs:             []string{},
 	}
 	c.StreamFactory = stream.NewFactory(targetRegistryClient, stream.MaxNumberOfTargets, c)
 	c.StreamManager = NewStreamManager(configurationManagerClient, targetRegistryClient, streamRegistry, c.StreamFactory, PendingTime)
@@ -117,6 +117,7 @@ func (c *Conduit) Connect(ctx context.Context) error {
 	}
 	logrus.Infof("Conduit connected: %v", c.Conduit)
 	c.connection = connection
+	c.localIPs = c.connection.GetContext().GetIpContext().GetSrcIpAddrs()
 
 	c.Configuration.Watch()
 
@@ -132,9 +133,6 @@ func (c *Conduit) Disconnect(ctx context.Context) error {
 	logrus.Infof("Disconnect from conduit: %v", c.Conduit)
 	// Stops the configuration
 	c.Configuration.Stop()
-	// reset the VIPs related configuration
-	c.deleteVIPs(c.vips)
-	c.tableID = 1
 	var errFinal error
 	// Stop the stream manager (close the streams)
 	errFinal = c.StreamManager.Stop(ctx)
@@ -174,7 +172,7 @@ func (c *Conduit) GetConduit() *ambassadorAPI.Conduit {
 // GetStreams returns the local IPs for this conduit
 func (c *Conduit) GetIPs() []string {
 	if c.connection != nil {
-		return c.connection.GetContext().GetIpContext().GetSrcIpAddrs()
+		return c.localIPs
 	}
 	return []string{}
 }
@@ -186,34 +184,65 @@ func (c *Conduit) SetVIPs(vips []string) error {
 	if !c.isConnected() {
 		return nil
 	}
-	currentVIPs := make(map[string]*virtualIP)
-	for _, vip := range c.vips {
-		currentVIPs[vip.prefix] = vip
+	// prepare SrcIpAddrs (IPs allocated by the proxy + VIPs)
+	c.connection.Context.IpContext.SrcIpAddrs = append(c.GetIPs(), vips...)
+	// prepare the routes (nexthops = proxy bridge IPs)
+	ipv4Nexthops := []*networkservice.Route{}
+	ipv6Nexthops := []*networkservice.Route{}
+	for _, nexthop := range c.getGateways() {
+		gw, _, err := net.ParseCIDR(nexthop)
+		if err != nil {
+			continue
+		}
+		route := &networkservice.Route{
+			NextHop: gw.String(),
+		}
+		if isIPv6(nexthop) {
+			route.Prefix = "::/0"
+			ipv6Nexthops = append(ipv6Nexthops, route)
+		} else {
+			route.Prefix = "0.0.0.0/0"
+			ipv4Nexthops = append(ipv4Nexthops, route)
+		}
 	}
+	// prepare the policies (only based on VIP address for now)
+	c.connection.Context.IpContext.Policies = []*networkservice.PolicyRoute{}
 	for _, vip := range vips {
-		if _, ok := currentVIPs[vip]; !ok {
-			newVIP, err := newVirtualIP(vip, c.tableID, c.NetUtils)
-			if err != nil {
-				logrus.Errorf("SimpleTarget: Error adding SourceBaseRoute: %v", err) // todo: err handling
-				continue
-			}
-			c.tableID++
-			c.vips = append(c.vips, newVIP)
-			for _, nexthop := range c.getGateways() {
-				err = newVIP.AddNexthop(nexthop)
-				if err != nil {
-					logrus.Errorf("Client: Error adding nexthop: %v", err) // todo: err handling
-				}
-			}
+		nexthops := ipv4Nexthops
+		if isIPv6(vip) {
+			nexthops = ipv6Nexthops
 		}
-		delete(currentVIPs, vip)
+		newPolicyRoute := &networkservice.PolicyRoute{
+			From:   vip,
+			Routes: nexthops,
+		}
+		c.connection.Context.IpContext.Policies = append(c.connection.Context.IpContext.Policies, newPolicyRoute)
 	}
-	// delete remaining vips
-	vipsSlice := []*virtualIP{}
-	for _, vip := range currentVIPs {
-		vipsSlice = append(vipsSlice, vip)
+	var err error
+	// update the NSM connection
+	// TODO: retry if error returned?
+	c.connection, err = c.NetworkServiceClient.Request(context.TODO(),
+		&networkservice.NetworkServiceRequest{
+			Connection: &networkservice.Connection{
+				Id:             c.connection.GetId(),
+				NetworkService: c.connection.GetNetworkService(),
+				Labels:         c.connection.GetLabels(),
+				Payload:        c.connection.GetPayload(),
+				Context: &networkservice.ConnectionContext{
+					IpContext: c.connection.GetContext().GetIpContext(),
+				},
+			},
+			MechanismPreferences: []*networkservice.Mechanism{
+				{
+					Cls:  cls.LOCAL,
+					Type: kernelmech.MECHANISM,
+				},
+			},
+		})
+	if err != nil {
+		return fmt.Errorf("error updating the VIPs in conduit: %v - %v", c.Conduit, err)
 	}
-	c.deleteVIPs(vipsSlice)
+	logrus.Infof("VIPs in conduit updated: %v - %v", c.Conduit, vips)
 	return nil
 }
 
@@ -226,22 +255,8 @@ func (c *Conduit) isConnected() bool {
 	return c.connection != nil
 }
 
-func (c *Conduit) deleteVIPs(vips []*virtualIP) {
-	vipsMap := make(map[string]*virtualIP)
-	for _, vip := range vips {
-		vipsMap[vip.prefix] = vip
-	}
-	for index := 0; index < len(c.vips); index++ {
-		vip := c.vips[index]
-		if _, ok := vipsMap[vip.prefix]; ok {
-			c.vips = append(c.vips[:index], c.vips[index+1:]...)
-			index--
-			err := vip.Delete()
-			if err != nil {
-				logrus.Errorf("Client: Error deleting vip: %v", err) // todo: err handling
-			}
-		}
-	}
+func isIPv6(address string) bool {
+	return strings.Count(address, ":") >= 2
 }
 
 // TODO: Requires the IPs of the bridge