feat: add support for windows MAC hex dump

Author: Keith Nguyen

cns/imds/client.go

@@ -9,6 +9,7 @@ import (
 	"net"
 	"net/http"
 	"net/url"
+	"strings"
 
 	"github.com/avast/retry-go/v4"
 	"github.com/pkg/errors"
@@ -218,14 +219,36 @@ func (h *HardwareAddr) UnmarshalJSON(data []byte) error {
 	if err := json.Unmarshal(data, &s); err != nil {
 		return errors.Wrap(err, "failed to unmarshal JSON data")
 	}
-	mac, err := net.ParseMAC(s)
+
+	mac, err := parseMacAddress(s)
 	if err != nil {
 		return errors.Wrap(err, "failed to parse MAC address")
 	}
 	*h = HardwareAddr(mac)
 	return nil
 }
 
+// parseMacAddress is a wrapper around net.ParseMAC to handle Windows MAC address. Windows MAC addresse is a pure hex
+// dump without delimiter, so we need to add delimiters. This happens when CNS gets MAC address from IMDS.
+func parseMacAddress(s string) (net.HardwareAddr, error) {
+	if !strings.ContainsAny(s, ":-.") && len(s)%2 == 0 {
+		var sb strings.Builder
+		for i := 0; i < len(s); i += 2 {
+			if i > 0 {
+				sb.WriteByte(':')
+			}
+			sb.WriteString(s[i : i+2])
+		}
+		s = sb.String()
+	}
+
+	mac, err := net.ParseMAC(s)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to parse MAC address")
+	}
+	return mac, nil
+}
+
 func (h *HardwareAddr) String() string {
 	return net.HardwareAddr(*h).String()
 }

cns/imds/client_test.go

@@ -111,7 +111,7 @@ func TestGetNetworkInterfaces(t *testing.T) {
             },
             {
                 "interfaceCompartmentID": "",
-                "macAddress": "00:00:5e:00:53:02"
+                "macAddress": "00005e005302"
             }
         ]
     }`)