fix: HTTPRouteHostnameIntersection test case

internal/controller/httproute_controller.go

@@ -201,11 +201,24 @@ func (r *HTTPRouteReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 	}
 	ProcessBackendTrafficPolicy(r.Client, r.Log, tctx)
 
-	if err := r.Provider.Update(ctx, tctx, hr); err != nil {
+	filteredHTTPRoute, err := filterHostnames(gateways, hr.DeepCopy())
+	if err != nil {
 		acceptStatus.status = false
 		acceptStatus.msg = err.Error()
 	}
 
+	if isRouteAccepted(gateways) && err == nil {
+		routeToUpdate := hr
+		if filteredHTTPRoute != nil {
+			r.Log.Info("filteredHTTPRoute", "filteredHTTPRoute", filteredHTTPRoute)
+			routeToUpdate = filteredHTTPRoute
+		}
+		if err := r.Provider.Update(ctx, tctx, routeToUpdate); err != nil {
+			acceptStatus.status = false
+			acceptStatus.msg = err.Error()
+		}
+	}
+
 	// TODO: diff the old and new status
 	hr.Status.Parents = make([]gatewayv1.RouteParentStatus, 0, len(gateways))
 	for _, gateway := range gateways {
@@ -214,9 +227,6 @@ func (r *HTTPRouteReconciler) Reconcile(ctx context.Context, req ctrl.Request) (
 		for _, condition := range gateway.Conditions {
 			parentStatus.Conditions = MergeCondition(parentStatus.Conditions, condition)
 		}
-		if gateway.ListenerName == "" {
-			continue
-		}
 		SetRouteConditionAccepted(&parentStatus, hr.GetGeneration(), acceptStatus.status, acceptStatus.msg)
 		SetRouteConditionResolvedRefs(&parentStatus, hr.GetGeneration(), resolveRefStatus.status, resolveRefStatus.msg)
 		hr.Status.Parents = append(hr.Status.Parents, parentStatus)

internal/controller/utils.go

@@ -14,6 +14,7 @@ package controller
 
 import (
 	"context"
+	"errors"
 	"fmt"
 	"path"
 	"reflect"
@@ -48,6 +49,10 @@ const (
 
 const defaultIngressClassAnnotation = "ingressclass.kubernetes.io/is-default-class"
 
+var (
+	ErrNoMatchingListenerHostname = errors.New("no matching hostnames in listener")
+)
+
 // IsDefaultIngressClass returns whether an IngressClass is the default IngressClass.
 func IsDefaultIngressClass(obj client.Object) bool {
 	if ingressClass, ok := obj.(*networkingv1.IngressClass); ok {
@@ -229,10 +234,15 @@ func SetRouteConditionAccepted(routeParentStatus *gatewayv1.RouteParentStatus, g
 		conditionStatus = metav1.ConditionFalse
 	}
 
+	reason := gatewayv1.RouteReasonAccepted
+	if message == ErrNoMatchingListenerHostname.Error() {
+		reason = gatewayv1.RouteReasonNoMatchingListenerHostname
+	}
+
 	condition := metav1.Condition{
 		Type:               string(gatewayv1.RouteConditionAccepted),
 		Status:             conditionStatus,
-		Reason:             string(gatewayv1.RouteReasonAccepted),
+		Reason:             string(reason),
 		ObservedGeneration: generation,
 		Message:            message,
 		LastTransitionTime: metav1.Now(),
@@ -458,39 +468,51 @@ func HostnamesIntersect(a, b string) bool {
 	return HostnamesMatch(a, b) || HostnamesMatch(b, a)
 }
 
+// HostnamesMatch checks that the hostnameB matches the hostnameA. HostnameA is treated as mask
+// to be checked against the hostnameB.
 func HostnamesMatch(hostnameA, hostnameB string) bool {
-	labelsA := strings.Split(hostnameA, ".")
-	labelsB := strings.Split(hostnameB, ".")
+	// the hostnames are in the form of "foo.bar.com"; split them
+	// in a slice of substrings
+	hostnameALabels := strings.Split(hostnameA, ".")
+	hostnameBLabels := strings.Split(hostnameB, ".")
 
-	var i, j int
+	var a, b int
 	var wildcard bool
 
-	for i, j = 0, 0; i < len(labelsA) && j < len(labelsB); i, j = i+1, j+1 {
+	// iterate over the parts of both the hostnames
+	for a, b = 0, 0; a < len(hostnameALabels) && b < len(hostnameBLabels); a, b = a+1, b+1 {
+		var matchFound bool
+
+		// if the current part of B is a wildcard, we need to find the first
+		// A part that matches with the following B part
 		if wildcard {
-			for ; j < len(labelsB); j++ {
-				if labelsA[i] == labelsB[j] {
+			for ; b < len(hostnameBLabels); b++ {
+				if hostnameALabels[a] == hostnameBLabels[b] {
+					matchFound = true
 					break
 				}
 			}
-			if j == len(labelsB) {
-				return false
-			}
 		}
 
-		if labelsA[i] == "*" {
+		// if no match was found, the hostnames don't match
+		if wildcard && !matchFound {
+			return false
+		}
+
+		// check if at least on of the current parts are a wildcard; if so, continue
+		if hostnameALabels[a] == "*" {
 			wildcard = true
-			j--
 			continue
 		}
-
+		// reset the wildcard  variables
 		wildcard = false
 
-		if labelsA[i] != labelsB[j] {
+		// if the current a part is different from the b part, the hostnames are incompatible
+		if hostnameALabels[a] != hostnameBLabels[b] {
 			return false
 		}
 	}
-
-	return len(labelsA)-i == len(labelsB)-j
+	return len(hostnameBLabels)-b == len(hostnameALabels)-a
 }
 
 func routeMatchesListenerAllowedRoutes(
@@ -892,3 +914,115 @@ func IsInvalidKindError(err error) bool {
 	_, ok := err.(*InvalidKindError)
 	return ok
 }
+
+// filterHostnames accepts a list of gateways and an HTTPRoute, and returns a copy of the HTTPRoute with only the hostnames that match the listener hostnames of the gateways.
+// If the HTTPRoute hostnames do not intersect with the listener hostnames of the gateways, it returns an ErrNoMatchingListenerHostname error.
+func filterHostnames(gateways []RouteParentRefContext, httpRoute *gatewayv1.HTTPRoute) (*gatewayv1.HTTPRoute, error) {
+	filteredHostnames := make([]gatewayv1.Hostname, 0)
+
+	// If the HTTPRoute does not specify hostnames, we use the union of the listener hostnames of all supported gateways
+	// If any supported listener does not specify a hostname, the HTTPRoute hostnames remain empty to match any hostname
+	if len(httpRoute.Spec.Hostnames) == 0 {
+		hostnames, matchAnyHost := getUnionOfGatewayHostnames(gateways)
+		if matchAnyHost {
+			return httpRoute, nil
+		}
+		filteredHostnames = hostnames
+	} else {
+		// If the HTTPRoute specifies hostnames, we need to find the intersection with the gateway listener hostnames
+		for _, hostname := range httpRoute.Spec.Hostnames {
+			if hostnameMatching := getMinimumHostnameIntersection(gateways, hostname); hostnameMatching != "" {
+				filteredHostnames = append(filteredHostnames, hostnameMatching)
+			}
+		}
+		if len(filteredHostnames) == 0 {
+			return httpRoute, ErrNoMatchingListenerHostname
+		}
+	}
+
+	log.Debugw("filtered hostnames", zap.Any("httpRouteHostnames", httpRoute.Spec.Hostnames), zap.Any("hostnames", filteredHostnames))
+	httpRoute.Spec.Hostnames = filteredHostnames
+	return httpRoute, nil
+}
+
+// getUnionOfGatewayHostnames returns the union of the hostnames specified in all supported gateways
+// The second return value indicates whether any listener can match any hostname
+func getUnionOfGatewayHostnames(gateways []RouteParentRefContext) ([]gatewayv1.Hostname, bool) {
+	hostnames := make([]gatewayv1.Hostname, 0)
+
+	for _, gateway := range gateways {
+		if gateway.ListenerName != "" {
+			// If a listener name is specified, only check that listener
+			for _, listener := range gateway.Gateway.Spec.Listeners {
+				if string(listener.Name) == gateway.ListenerName {
+					// If a listener does not specify a hostname, it can match any hostname
+					if listener.Hostname == nil {
+						return nil, true
+					}
+					hostnames = append(hostnames, *listener.Hostname)
+					break
+				}
+			}
+		} else {
+			// Otherwise, check all listeners
+			for _, listener := range gateway.Gateway.Spec.Listeners {
+				// Only consider listeners that can effectively configure hostnames (HTTP, HTTPS, or TLS)
+				if isListenerHostnameEffective(listener) {
+					if listener.Hostname == nil {
+						return nil, true
+					}
+					hostnames = append(hostnames, *listener.Hostname)
+				}
+			}
+		}
+	}
+
+	return hostnames, false
+}
+
+// getMinimumHostnameIntersection returns the smallest intersection hostname
+// - If the listener hostname is empty, return the HTTPRoute hostname
+// - If the listener hostname is a wildcard of the HTTPRoute hostname, return the HTTPRoute hostname
+// - If the HTTPRoute hostname is a wildcard of the listener hostname, return the listener hostname
+// - If the HTTPRoute hostname and listener hostname are the same, return it
+// - If none of the above, return an empty string
+func getMinimumHostnameIntersection(gateways []RouteParentRefContext, hostname gatewayv1.Hostname) gatewayv1.Hostname {
+	for _, gateway := range gateways {
+		for _, listener := range gateway.Gateway.Spec.Listeners {
+			// If a listener name is specified, only check that listener
+			// If the listener name is not specified, check all listeners
+			if gateway.ListenerName == "" || gateway.ListenerName == string(listener.Name) {
+				if listener.Hostname == nil || *listener.Hostname == "" {
+					return hostname
+				}
+				if HostnamesMatch(string(*listener.Hostname), string(hostname)) {
+					return hostname
+				}
+				if HostnamesMatch(string(hostname), string(*listener.Hostname)) {
+					return *listener.Hostname
+				}
+			}
+		}
+	}
+
+	return ""
+}
+
+// isListenerHostnameEffective checks if a listener can specify a hostname to match the hostname in the request
+// Basically, check if the listener uses HTTP, HTTPS, or TLS protocol
+func isListenerHostnameEffective(listener gatewayv1.Listener) bool {
+	return listener.Protocol == gatewayv1.HTTPProtocolType ||
+		listener.Protocol == gatewayv1.HTTPSProtocolType ||
+		listener.Protocol == gatewayv1.TLSProtocolType
+}
+
+func isRouteAccepted(gateways []RouteParentRefContext) bool {
+	for _, gateway := range gateways {
+		for _, condition := range gateway.Conditions {
+			if condition.Type == string(gatewayv1.RouteConditionAccepted) && condition.Status == metav1.ConditionTrue {
+				return true
+			}
+		}
+	}
+	return false
+}

test/conformance/conformance_test.go

@@ -34,11 +34,10 @@ var skippedTestsForTraditionalRoutes = []string{
 	tests.HTTPRouteReferenceGrant.ShortName,
 
 	// TODO: HTTPRoute hostname intersection and listener hostname matching
-	tests.HTTPRouteHostnameIntersection.ShortName,
-	tests.HTTPRouteListenerHostnameMatching.ShortName,
+	// tests.HTTPRouteHostnameIntersection.ShortName,
+	// tests.HTTPRouteListenerHostnameMatching.ShortName,
 
 	tests.GatewayInvalidTLSConfiguration.ShortName,
-	// tests.HTTPRouteInvalidBackendRefUnknownKind.ShortName,
 	tests.HTTPRouteInvalidCrossNamespaceParentRef.ShortName,
 	tests.HTTPRouteInvalidNonExistentBackendRef.ShortName,
 	tests.HTTPRouteInvalidParentRefNotMatchingSectionName.ShortName,