Add component mock

comp/rdnsquerier/mock/mock.go

@@ -10,6 +10,7 @@ package mock
 
 import (
 	"fmt"
+	"net"
 	"net/netip"
 
 	rdnsquerier "github.com/DataDog/datadog-agent/comp/rdnsquerier/def"
@@ -51,3 +52,18 @@ func (q *rdnsQuerierMock) GetHostname(ipAddr []byte, updateHostnameSync func(str
 
 	return nil
 }
+
+// GetHostnameSync simulates resolving the hostname for the given IP address synchronously.  If the IP address is in the private address
+// space then the resolved hostname is returned.
+func (q *rdnsQuerierMock) GetHostnameSync(ipAddr string) (string, error) {
+	ipaddr := net.ParseIP(ipAddr).To4()
+	if ipaddr == nil {
+		return "", fmt.Errorf("invalid IP address %v", ipAddr)
+	}
+
+	if !ipaddr.IsPrivate() {
+		return "", nil
+	}
+
+	return "hostname-" + ipaddr.String(), nil
+}