Minor simplification around naming of interfaces and aliases.

Signed-off-by: Ed Warnicke <hagbard@gmail.com>

pkg/networkservice/mechanisms/kernel/kerneltap/common.go

@@ -20,7 +20,6 @@ package kerneltap
 
 import (
 	"context"
-	"fmt"
 	"time"
 
 	"git.fd.io/govpp.git/api"
@@ -49,16 +48,6 @@ func create(ctx context.Context, conn *networkservice.Connection, vppConn api.Co
 			return err
 		}
 
-		// Naming is tricky.  We want to name based on either the next or prev connection id depending on whether we
-		// are on the client or server side.  Since this chain element is designed for use in a Forwarder,
-		// if we are on the client side, we want to name based on the connection id from the NSE that is Next
-		// if we are not the client, we want to name for the connection of of the client addressing us, which is Prev
-		namingConn := conn.Clone()
-		namingConn.Id = namingConn.GetPrevPathSegment().GetId()
-		if isClient {
-			namingConn.Id = namingConn.GetNextPathSegment().GetId()
-		}
-
 		now := time.Now()
 		tapCreateV2 := &tapv2.TapCreateV2{
 			ID:               ^uint32(0),
@@ -67,7 +56,7 @@ func create(ctx context.Context, conn *networkservice.Connection, vppConn api.Co
 			TxRingSz:         1024,
 			RxRingSz:         1024,
 			HostIfNameSet:    true,
-			HostIfName:       mechanism.GetInterfaceName(namingConn),
+			HostIfName:       mechutils.ToInterfaceName(conn, isClient),
 			HostNamespaceSet: true,
 			HostNamespace:    nsFilename,
 			//TapFlags:         0, // TODO - TUN support for v3 payloads
@@ -112,10 +101,7 @@ func create(ctx context.Context, conn *networkservice.Connection, vppConn api.Co
 			WithField("duration", time.Since(now)).
 			WithField("netlink", "LinkByName").Debug("completed")
 
-		alias := fmt.Sprintf("server-%s", namingConn.GetId())
-		if isClient {
-			alias = fmt.Sprintf("client-%s", namingConn.GetId())
-		}
+		alias := mechutils.ToAlias(conn, isClient)
 
 		// Set the Link Alias
 		now = time.Now()

pkg/networkservice/mechanisms/kernel/kernelvethpair/common.go

@@ -40,20 +40,8 @@ func create(ctx context.Context, conn *networkservice.Connection, isClient bool)
 		// TODO - short circuit if already done
 		la := netlink.NewLinkAttrs()
 
-		// Naming is tricky.  We want to name based on either the next or prev connection id depending on whether we
-		// are on the client or server side.  Since this chain element is designed for use in a Forwarder,
-		// if we are on the client side, we want to name based on the connection id from the NSE that is Next
-		// if we are not the client, we want to name for the connection of of the client addressing us, which is Prev
-		namingConn := conn.Clone()
-		namingConn.Id = namingConn.GetPrevPathSegment().GetId()
-		if isClient {
-			namingConn.Id = namingConn.GetNextPathSegment().GetId()
-		}
 		la.Name = randstr.Hex(7)
-		alias := fmt.Sprintf("server-%s", namingConn.GetId())
-		if isClient {
-			alias = fmt.Sprintf("client-%s", namingConn.GetId())
-		}
+		alias := mechutils.ToAlias(conn, isClient)
 
 		// Create the veth pair
 		now := time.Now()
@@ -108,7 +96,7 @@ func create(ctx context.Context, conn *networkservice.Connection, isClient bool)
 			WithField("link.Name", name).
 			WithField("netlink", "LinkByName").Debug("completed")
 
-		name = mechanism.GetInterfaceName(namingConn)
+		name = mechutils.ToInterfaceName(conn, isClient)
 		// Set the LinkName
 		now = time.Now()
 		if err = handle.LinkSetName(l, name); err != nil {

pkg/tools/mechutils/mechutils.go

@@ -20,8 +20,10 @@
 package mechutils
 
 import (
+	"fmt"
 	"net/url"
 
+	"github.com/networkservicemesh/api/pkg/api/networkservice"
 	"github.com/networkservicemesh/api/pkg/api/networkservice/mechanisms/kernel"
 	"github.com/pkg/errors"
 	"github.com/vishvananda/netlink"
@@ -70,3 +72,31 @@ func ToNetlinkHandle(mechanism *kernel.Mechanism) (*netlink.Handle, error) {
 	}
 	return handle, nil
 }
+
+func ToInterfaceName(conn *networkservice.Connection, isClient bool) string {
+	// Naming is tricky.  We want to name based on either the next or prev connection id depending on whether we
+	// are on the client or server side.  Since this chain element is designed for use in a Forwarder,
+	// if we are on the client side, we want to name based on the connection id from the NSE that is Next
+	// if we are not the client, we want to name for the connection of of the client addressing us, which is Prev
+	namingConn := conn.Clone()
+	namingConn.Id = namingConn.GetPrevPathSegment().GetId()
+	if isClient {
+		namingConn.Id = namingConn.GetNextPathSegment().GetId()
+	}
+	return kernel.ToMechanism(conn.GetMechanism()).GetInterfaceName(namingConn)
+}
+
+func ToAlias(conn *networkservice.Connection, isClient bool) string {
+	// Naming is tricky.  We want to name based on either the next or prev connection id depending on whether we
+	// are on the client or server side.  Since this chain element is designed for use in a Forwarder,
+	// if we are on the client side, we want to name based on the connection id from the NSE that is Next
+	// if we are not the client, we want to name for the connection of of the client addressing us, which is Prev
+	namingConn := conn.Clone()
+	namingConn.Id = namingConn.GetPrevPathSegment().GetId()
+	alias := fmt.Sprintf("server-%s", namingConn.GetId())
+	if isClient {
+		namingConn.Id = namingConn.GetNextPathSegment().GetId()
+		alias = fmt.Sprintf("client-%s", namingConn.GetId())
+	}
+	return alias
+}