From 25787126235087eda3f7e8deec4620acd54cf353 Mon Sep 17 00:00:00 2001
From: Vladimir Lavor <vlavor@cisco.com>
Date: Wed, 15 Dec 2021 12:07:29 +0100
Subject: [PATCH] Make route scope relevant for IPv4 only

Signed-off-by: Vladimir Lavor <vlavor@cisco.com>
---
 examples/localclient_linux/route/main.go   |  5 +--
 plugins/linux/l3plugin/descriptor/route.go | 37 ++++++++++++++--------
 2 files changed, 25 insertions(+), 17 deletions(-)

diff --git a/examples/localclient_linux/route/main.go b/examples/localclient_linux/route/main.go
index d2f8add484..bcce3291f1 100644
--- a/examples/localclient_linux/route/main.go
+++ b/examples/localclient_linux/route/main.go
@@ -178,7 +178,7 @@ func (p *RouteExamplePlugin) resync(ctx context.Context, timeout int) {
 			LinuxInterface(linuxTap()).
 			LinuxInterface(linuxTapIpv6()).
 			LinuxRoute(routeResync()).     // recreate
-			LinuxRoute(routeResyncIPv6()). // update
+			LinuxRoute(routeResyncIPv6()). // no action
 			Send().ReceiveReply()
 		if err != nil {
 			p.Log.Errorf("Resync failed: %v", err)
@@ -321,7 +321,6 @@ func routeIPv6() *linux_l3.Route {
 	return &linux_l3.Route{
 		OutgoingInterface: "linux-tap2",
 		DstNetwork:        "aaa1::/64",
-		Scope:             linux_l3.Route_GLOBAL,
 		Metric:            0,
 	}
 }
@@ -330,7 +329,6 @@ func routeResyncIPv6() *linux_l3.Route {
 	return &linux_l3.Route{
 		OutgoingInterface: "linux-tap2",
 		DstNetwork:        "aaa1::/64",
-		Scope:             linux_l3.Route_LINK,
 		Metric:            1024,
 	}
 }
@@ -339,7 +337,6 @@ func routeModifiedIPv6() *linux_l3.Route {
 	return &linux_l3.Route{
 		OutgoingInterface: "linux-tap2",
 		DstNetwork:        "aaa1::/64",
-		Scope:             linux_l3.Route_LINK,
 		Metric:            500,
 	}
 }
diff --git a/plugins/linux/l3plugin/descriptor/route.go b/plugins/linux/l3plugin/descriptor/route.go
index cb492f2dd3..88b7a1d551 100644
--- a/plugins/linux/l3plugin/descriptor/route.go
+++ b/plugins/linux/l3plugin/descriptor/route.go
@@ -122,10 +122,15 @@ func NewRouteDescriptor(
 // EquivalentRoutes is case-insensitive comparison function for l3.LinuxRoute.
 func (d *RouteDescriptor) EquivalentRoutes(key string, oldRoute, newRoute *linux_l3.Route) bool {
 	// attributes compared as usually:
-	if oldRoute.OutgoingInterface != newRoute.OutgoingInterface ||
-		oldRoute.Scope != newRoute.Scope {
+	if oldRoute.OutgoingInterface != newRoute.OutgoingInterface {
 		return false
 	}
+	// compare scopes for IPv4 routes
+	if ip := net.ParseIP(newRoute.DstNetwork); ip != nil && ip.To4() != nil {
+		if oldRoute.Scope != newRoute.Scope {
+			return false
+		}
+	}
 	// compare metrics
 	if !isRouteMetricEqual(oldRoute, newRoute) {
 		return false
@@ -230,13 +235,15 @@ func (d *RouteDescriptor) updateRoute(route *linux_l3.Route, actionName string,
 		netlinkRoute.Gw = gwAddr.IP
 	}
 
-	// set route scope
-	scope, err := rtScopeFromNBToNetlink(route.Scope)
-	if err != nil {
-		d.log.Error(err)
-		return err
+	// set route scope for IPv4
+	if ip := net.ParseIP(route.DstNetwork); ip != nil && ip.To4() != nil {
+		scope, err := rtScopeFromNBToNetlink(route.Scope)
+		if err != nil {
+			d.log.Error(err)
+			return err
+		}
+		netlinkRoute.Scope = scope
 	}
-	netlinkRoute.Scope = scope
 
 	// set route metric
 	netlinkRoute.Priority = int(route.Metric)
@@ -397,11 +404,15 @@ func (d *RouteDescriptor) Retrieve(correlate []adapter.RouteKVWithMetadata) ([]a
 
 	// correlate with the expected configuration
 	for _, routeDetails := range routeDetails {
-		// Convert to key-value object with metadata
-		scope, err := rtScopeFromNetlinkToNB(routeDetails.Meta.NetlinkScope)
-		if err != nil {
-			// route not configured by the agent
-			continue
+		// convert to key-value object with metadata
+		// resolve scope for IPv6. Note that IPv6 route scope always returns zero value.
+		var scope linux_l3.Route_Scope
+		if ip := net.ParseIP(routeDetails.Route.DstNetwork); ip != nil && ip.To4() != nil {
+			scope, err = rtScopeFromNetlinkToNB(routeDetails.Meta.NetlinkScope)
+			if err != nil {
+				// route not configured by the agent
+				continue
+			}
 		}
 		route := adapter.RouteKVWithMetadata{
 			Key: linux_l3.RouteKey(routeDetails.Route.DstNetwork, routeDetails.Route.OutgoingInterface),