gateway-api: migrate net.IP usage to net/netip

Convert the remaining net.IP usage in the Gateway API operator to
netip.Addr, as part of the tree-wide migration tracked in cilium#24246.

In setAddressStatus, the NodePort branch now parses node addresses
with netip.ParseAddr and sorts them with netip.Addr.Compare. Nodes
whose first status address is not an IP address (e.g. a Hostname
entry) are now skipped instead of being appended as a nil net.IP,
which previously rendered as a bogus "<nil>" address in the Gateway
status. Parsed addresses are Unmap()-ed so IPv4-mapped IPv6 inputs
keep rendering in dotted-quad form as before. Note that mixed IPv4
and IPv6 addresses now sort IPv4-first instead of interleaving the
IPv4-mapped form within the IPv6 space; the sort only exists to keep
the assigned addresses deterministic, which is preserved.

In verifyGatewayStaticAddresses, netip.ParseAddr replaces the
net.ParseIP nil check. Parsing semantics are unchanged for valid
IPv4/IPv6 literals; zoned IPv6 literals are additionally accepted.

The nodeport testdata gains a node whose only status address is a
Hostname entry, locking in the new skip behavior.

Related: cilium#24246
Signed-off-by: Dean Chen <862469039@qq.com>

Author: locker95

operator/pkg/gateway-api/gateway_reconcile.go

@@ -4,13 +4,12 @@
 package gateway_api
 
 import (
-	"bytes"
 	"context"
 	"errors"
 	"fmt"
 	"log/slog"
-	"net"
-	"sort"
+	"net/netip"
+	"slices"
 	"strings"
 
 	"github.com/google/go-cmp/cmp"
@@ -1116,19 +1115,23 @@ func (r *gatewayReconciler) setAddressStatus(ctx context.Context, gw *gatewayv1.
 			return fmt.Errorf("unable to list nodes")
 		}
 
-		ips := make([]net.IP, 0)
+		ips := make([]netip.Addr, 0)
 		for _, node := range nodes.Items {
 			if len(node.Status.Addresses) == 0 {
 				continue
 			}
 			nodeAddress := node.Status.Addresses[0]
-			ips = append(ips, net.ParseIP(nodeAddress.Address))
+			ip, err := netip.ParseAddr(nodeAddress.Address)
+			if err != nil {
+				// the first address is not an IP address (e.g. a hostname),
+				// skip the node instead of reporting an invalid address.
+				continue
+			}
+			ips = append(ips, ip.Unmap())
 		}
 
 		// sort the addresses for consistent ip addresses assigned
-		sort.Slice(ips, func(i, j int) bool {
-			return bytes.Compare(ips[i], ips[j]) < 0
-		})
+		slices.SortFunc(ips, netip.Addr.Compare)
 
 		// allows for only a max of 16 addresses
 		if len(ips) > 16 {
@@ -1560,8 +1563,7 @@ func (r *gatewayReconciler) verifyGatewayStaticAddresses(gw *gatewayv1.Gateway)
 		if address.Value == "" {
 			return fmt.Errorf("address value is not set")
 		}
-		ip := net.ParseIP(address.Value)
-		if ip == nil {
+		if _, err := netip.ParseAddr(address.Value); err != nil {
 			return fmt.Errorf("invalid ip address")
 		}
 	}

operator/pkg/gateway-api/testdata/gateway/gatewayclassconfig-nodeport/input/nodeport-gateway.yaml

@@ -84,3 +84,17 @@ status:
     type: InternalIP
   - address: kind-worker
     type: Hostname
+---
+apiVersion: v1
+kind: Node
+metadata:
+  name: kind-worker3
+spec:
+  podCIDR: 10.244.2.0/24
+  podCIDRs:
+  - 10.244.2.0/24
+  - fd00:10:244:2::/64
+status:
+  addresses:
+  - address: kind-worker3
+    type: Hostname