Cherry Pick #956 into release-0.4

apis/v1alpha2/httproute_types.go

@@ -683,7 +683,7 @@ type HTTPRequestRedirectFilter struct {
 	// Support: Core
 	//
 	// +optional
-	Hostname *Hostname `json:"hostname,omitempty"`
+	Hostname *PreciseHostname `json:"hostname,omitempty"`
 
 	// Port is the port to be used in the value of the `Location`
 	// header in the response.

apis/v1alpha2/shared_types.go

@@ -252,6 +252,24 @@ type RouteStatus struct {
 // +kubebuilder:validation:Pattern=`^(\*\.)?[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$`
 type Hostname string
 
+// PreciseHostname is the fully qualified domain name of a network host. This matches
+// the RFC 1123 definition of a hostname with 2 notable exceptions:
+//
+// 1. IPs are not allowed.
+// 2. A hostname may not be prefixed with a wildcard label (`*.`).
+//
+// Hostname can be "precise" which is a domain name without the terminating
+// dot of a network host (e.g. "foo.example.com").
+//
+// Note that as per RFC1035 and RFC1123, a *label* must consist of lower case
+// alphanumeric characters or '-', and must start and end with an alphanumeric
+// character. No other punctuation is allowed.
+//
+// +kubebuilder:validation:MinLength=1
+// +kubebuilder:validation:MaxLength=253
+// +kubebuilder:validation:Pattern=`^[a-z0-9]([-a-z0-9]*[a-z0-9])?(\.[a-z0-9]([-a-z0-9]*[a-z0-9])?)*$`
+type PreciseHostname string
+
 // Group refers to a Kubernetes Group. It must either be an empty string or a
 // RFC 1123 subdomain.
 //

hack/invalid-examples/v1alpha2/httproute/invalid-httredirect-hostname.yaml

@@ -0,0 +1,14 @@
+apiVersion: gateway.networking.k8s.io/v1alpha2
+kind: HTTPRoute
+metadata:
+  name: invalid-backend-port
+spec:
+  rules:
+  - backendRefs:
+    - name: my-service
+      port: 8080
+    filters:
+    - type: RequestRedirect
+      requestRedirect:
+        hostname: "*.gateway.networking.k8s.io"
+