[client] Remove legacy forwarding rules in userspace mode (#2782)

client/firewall/iptables/router_linux.go

@@ -296,6 +296,8 @@ func (r *router) RemoveAllLegacyRouteRules() error {
 		}
 		if err := r.iptablesClient.DeleteIfExists(tableFilter, chainRTFWD, rule...); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("remove legacy forwarding rule: %v", err))
+		} else {
+			delete(r.rules, k)
 		}
 	}
 

client/firewall/nftables/manager_linux.go

@@ -230,23 +230,7 @@ func (m *Manager) AllowNetbird() error {
 
 // SetLegacyManagement sets the route manager to use legacy management
 func (m *Manager) SetLegacyManagement(isLegacy bool) error {
-	oldLegacy := m.router.legacyManagement
-
-	if oldLegacy != isLegacy {
-		m.router.legacyManagement = isLegacy
-		log.Debugf("Set legacy management to %v", isLegacy)
-	}
-
-	// client reconnected to a newer mgmt, we need to cleanup the legacy rules
-	if !isLegacy && oldLegacy {
-		if err := m.router.RemoveAllLegacyRouteRules(); err != nil {
-			return fmt.Errorf("remove legacy routing rules: %v", err)
-		}
-
-		log.Debugf("Legacy routing rules removed")
-	}
-
-	return nil
+	return firewall.SetLegacyManagement(m.router, isLegacy)
 }
 
 // Reset firewall to the default state

client/firewall/nftables/router_linux.go

@@ -551,7 +551,10 @@ func (r *router) RemoveAllLegacyRouteRules() error {
 		}
 		if err := r.conn.DelRule(rule); err != nil {
 			merr = multierror.Append(merr, fmt.Errorf("remove legacy forwarding rule: %v", err))
+		} else {
+			delete(r.rules, k)
 		}
+
 	}
 	return nberrors.FormatErrorOrNil(merr)
 }

client/firewall/uspfilter/uspfilter.go

@@ -237,8 +237,11 @@ func (m *Manager) DeletePeerRule(rule firewall.Rule) error {
 }
 
 // SetLegacyManagement doesn't need to be implemented for this manager
-func (m *Manager) SetLegacyManagement(_ bool) error {
-	return nil
+func (m *Manager) SetLegacyManagement(isLegacy bool) error {
+	if m.nativeFirewall == nil {
+		return errRouteNotSupported
+	}
+	return m.nativeFirewall.SetLegacyManagement(isLegacy)
 }
 
 // Flush doesn't need to be implemented for this manager