iptables: optional loading of static extensions

Make loading of static extensions optional to support vanilla iptables
in it's default configuration by setting DISABLE_STATIC_EXTENSIONS
instead of hackery.

In case iptables is built with --disable-static libext.a, libext4.a and
libext6.a which OpenWrt installs in the form of libiptext.so,
libiptext4.so, libiptext6.so to save a couple more bytes are of no use
or non-existent one could say. So this commit avoids requiring a
tampered with iptables.

Signed-off-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
[Jo-Philipp Wich: stub init_extensions*() instead to reduce amount of ifdefs]
Signed-off-by: Jo-Philipp Wich <jo@mein.io>

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 00d14449d1511b4a85952711521454f7bccb0b39..e2a88e7e1d22a2d5428a35531a36cd9d2e09cc34 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -7,11 +7,17 @@ SET(iptc_libs   ip4tc)
 
 SET(CMAKE_SHARED_LIBRARY_LINK_C_FLAGS "")
 
-LIST(APPEND ext_libs iptext)
-LIST(APPEND ext_libs iptext4)
+IF (NOT DISABLE_STATIC_EXTENSIONS)
+  LIST(APPEND ext_libs iptext)
+  LIST(APPEND ext_libs iptext4)
+  IF (NOT DISABLE_IPV6)
+    LIST(APPEND ext_libs iptext6)
+  ENDIF()
+ELSE()
+  ADD_DEFINITIONS(-DDISABLE_STATIC_EXTENSIONS)
+ENDIF()
 
 IF (NOT DISABLE_IPV6)
-  LIST(APPEND ext_libs iptext6)
   LIST(APPEND iptc_libs ip6tc)
 ELSE()
   ADD_DEFINITIONS(-DDISABLE_IPV6)

diff --git a/iptables.h b/iptables.h
index bcd302d841d145208254e933d1ae062a0948c3bb..efd7cf38c32c7c210173631f1c7acb9ad042ad15 100644 (file)
--- a/iptables.h
+++ b/iptables.h
@@ -42,10 +42,16 @@
 # error "Unsupported xtables version"
 #endif
 
+#ifndef DISABLE_STATIC_EXTENSIONS
 /* libipt*ext.so interfaces */
 extern void init_extensions(void);
 extern void init_extensions4(void);
 extern void init_extensions6(void);
+#else
+static inline void init_extensions(void) { }
+static inline void init_extensions4(void) { }
+static inline void init_extensions6(void) { }
+#endif
 
 /* Required by certain extensions like SNAT and DNAT */
 extern int kernel_version;