From 450658e32b6d1f7529ad322d7361a680a97888df Mon Sep 17 00:00:00 2001
From: Jakob Schrettenbrunner <jakob.schrettenbrunner@telekom.de>
Date: Tue, 11 Apr 2023 10:58:32 +0200
Subject: [PATCH] ipam: fix gateway being required for IPAddress

---
 exp/ipam/internal/webhooks/ipaddress.go      | 17 +++++++++--------
 exp/ipam/internal/webhooks/ipaddress_test.go |  8 ++++++++
 2 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/exp/ipam/internal/webhooks/ipaddress.go b/exp/ipam/internal/webhooks/ipaddress.go
index 45c4f5cf05e9..6cf6b056ae9a 100644
--- a/exp/ipam/internal/webhooks/ipaddress.go
+++ b/exp/ipam/internal/webhooks/ipaddress.go
@@ -123,14 +123,15 @@ func (webhook *IPAddress) validate(ctx context.Context, ip *ipamv1.IPAddress) er
 			))
 	}
 
-	_, err = netip.ParseAddr(ip.Spec.Gateway)
-	if err != nil {
-		allErrs = append(allErrs,
-			field.Invalid(
-				specPath.Child("gateway"),
-				ip.Spec.Gateway,
-				"not a valid IP address",
-			))
+	if ip.Spec.Gateway != "" {
+		if _, err := netip.ParseAddr(ip.Spec.Gateway); err != nil {
+			allErrs = append(allErrs,
+				field.Invalid(
+					specPath.Child("gateway"),
+					ip.Spec.Gateway,
+					"not a valid IP address",
+				))
+		}
 	}
 
 	if ip.Spec.PoolRef.APIGroup == nil {
diff --git a/exp/ipam/internal/webhooks/ipaddress_test.go b/exp/ipam/internal/webhooks/ipaddress_test.go
index 5c8809fa253c..5cdad9a5ddcf 100644
--- a/exp/ipam/internal/webhooks/ipaddress_test.go
+++ b/exp/ipam/internal/webhooks/ipaddress_test.go
@@ -130,6 +130,14 @@ func TestIPAddressValidateCreate(t *testing.T) {
 			extraObjs: []client.Object{claim},
 			expectErr: true,
 		},
+		{
+			name: "an empty gateway should be allowed",
+			ip: getAddress(false, func(addr *ipamv1.IPAddress) {
+				addr.Spec.Gateway = ""
+			}),
+			extraObjs: []client.Object{claim},
+			expectErr: false,
+		},
 		{
 			name: "a pool reference that does not match the claim should be rejected",
 			ip: getAddress(false, func(addr *ipamv1.IPAddress) {