add checks for netfilter's headers

config.h.in

@@ -79,6 +79,16 @@
 /* Define to 1 if you have the `socket' library (-lsocket). */
 #undef HAVE_LIBSOCKET
 
+/* Define to 1 if you have the <linux/if.h> header file. */
+#undef HAVE_LINUX_IF_H
+
+/* Define to 1 if you have the <linux/netfilter_ipv4.h> header file. */
+#undef HAVE_LINUX_NETFILTER_IPV4_H
+
+/* Define to 1 if you have the <linux/netfilter_ipv6/ip6_tables.h> header
+   file. */
+#undef HAVE_LINUX_NETFILTER_IPV6_IP6_TABLES_H
+
 /* Define to 1 if you have the <locale.h> header file. */
 #undef HAVE_LOCALE_H
 

configure

@@ -13290,6 +13290,35 @@ else
   as_fn_error $? "Missing MinGW headers" "$LINENO" 5
 fi
 
+done
+
+    ;;
+  *-linux*)
+        for ac_header in linux/if.h linux/netfilter_ipv4.h linux/netfilter_ipv6/ip6_tables.h
+do :
+  as_ac_Header=`$as_echo "ac_cv_header_$ac_header" | $as_tr_sh`
+ac_fn_c_check_header_compile "$LINENO" "$ac_header" "$as_ac_Header" "
+    #if HAVE_LIMITS_H
+    #include <limits.h>
+    #endif
+    /* Netfilter ip(6)tables v1.4.0 has broken headers */
+    #if HAVE_NETINET_IN_H
+    #include <netinet/in.h>
+    #endif
+    #if HAVE_LINUX_IF_H
+    #include <net/if.h>
+    #endif
+
+"
+if eval test \"x\$"$as_ac_Header"\" = x"yes"; then :
+  cat >>confdefs.h <<_ACEOF
+#define `$as_echo "HAVE_$ac_header" | $as_tr_cpp` 1
+_ACEOF
+
+else
+  as_fn_error $? "Missing netfilter headers" "$LINENO" 5
+fi
+
 done
 
     ;;

configure.ac

@@ -119,6 +119,23 @@ case $host in
   *-mingw*)
     AC_CHECK_HEADERS([windows.h winsock2.h ws2tcpip.h], [], [AC_MSG_ERROR([Missing MinGW headers])], [])
     ;;
+  *-linux*)
+    dnl Checks for netfilter headers
+    AC_CHECK_HEADERS([linux/if.h linux/netfilter_ipv4.h linux/netfilter_ipv6/ip6_tables.h],
+                     [], [AC_MSG_ERROR([Missing netfilter headers])],
+    [[
+    #if HAVE_LIMITS_H
+    #include <limits.h>
+    #endif
+    /* Netfilter ip(6)tables v1.4.0 has broken headers */
+    #if HAVE_NETINET_IN_H
+    #include <netinet/in.h>
+    #endif
+    #if HAVE_LINUX_IF_H
+    #include <net/if.h>
+    #endif
+    ]])
+    ;;
   *)
     # These are POSIX-like systems using BSD-like sockets API.
     ;;

src/redir.c

@@ -60,6 +60,10 @@
 #define BUF_SIZE 2048
 #endif
 
+#ifndef IP6T_SO_ORIGINAL_DST
+#define IP6T_SO_ORIGINAL_DST 80
+#endif
+
 int getdestaddr(int fd, struct sockaddr_storage *destaddr)
 {
     socklen_t socklen = sizeof(*destaddr);