[MINOR] add transparent proxy support for balabit's Tproxy v4
Balabit's TPROXY version 4 which replaces CTTPROXY provides a similar
API to the previous proxy, but relies on IP_FREEBIND instead of
IP_TRANSPARENT. Let's add it.
diff --git a/include/common/compat.h b/include/common/compat.h
index 3c51fb2..9cce1f5 100644
--- a/include/common/compat.h
+++ b/include/common/compat.h
@@ -66,8 +66,11 @@
#include <linux/netfilter_ipv4.h>
#endif
-/* On Linux, IP_TRANSPARENT generally requires a kernel patch */
+/* On Linux, IP_TRANSPARENT and/or IP_FREEBIND generally require a kernel patch */
#if defined(CONFIG_HAP_LINUX_TPROXY)
+#if !defined(IP_FREEBIND)
+#define IP_FREEBIND 15
+#endif /* !IP_FREEBIND */
#if !defined(IP_TRANSPARENT)
#define IP_TRANSPARENT 19
#endif /* !IP_TRANSPARENT */