use nf_tables and nf_tables compatibility interface

This patch adds the following utilities:

* xtables
* xtables-restore
* xtables-save
* xtables-config

They all use Patrick's nf_tables infrastructure plus my compatibility
layer.

xtables, xtables-restore and xtables-save are syntax compatible with
ip[6]tables, ip[6]tables-restore and ip[6]tables-save.

Semantics aims to be similar, still the main exception is that there
is no commit operation. Thus, we incrementally add/delete rules without
entire table locking.

The following options are also not yet implemented:

-Z (this requires adding expr->ops->reset(...) so nft_counters can reset
    internal state of expressions while dumping it)

-R and -E (this requires adding this feature to nf_tables)

-f (can be implemented with expressions: payload 6 (2-bytes) + bitwise a&b^!b + cmp neq 0)

-IPv6 support.

But those are a matter of time to get them done.

A new utility, xtables-config, is available to register tables and
chains. By default there is a configuration file that adds backward
compatible tables and chains under iptables/etc/xtables.conf. You have
to call this utility first to register tables and chains.

However, it would be possible to automagically register tables and
chains while using xtables and xtables-restore to get similar operation
than with iptables.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/iptables/xtables-config-syntax.l b/iptables/xtables-config-syntax.l
new file mode 100644
index 00000000..7a66ef39
--- /dev/null
+++ b/iptables/xtables-config-syntax.l
@@ -0,0 +1,53 @@
+%{
+/*
+ * (C) 2012 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This software has been sponsored by Sophos Astaro <http://www.sophos.com>
+ */
+
+#include <string.h>
+#include "xtables-config-parser.h"
+%}
+
+%option yylineno
+%option noinput
+%option nounput
+
+ws		[ \t]+
+comment         #.*$
+nl		[\n\r]
+
+is_on		[o|O][n|N]
+is_off		[o|O][f|F][f|F]
+integer		[\-\+]?[0-9]+
+string		[a-zA-Z][a-zA-Z0-9\.\-\_]*
+
+%%
+"table"			{ return T_TABLE; }
+"chain"			{ return T_CHAIN; }
+"hook"			{ return T_HOOK; }
+"prio"			{ return T_PRIO; }
+
+{integer}		{ yylval.val = atoi(yytext); return T_INTEGER; }
+{string}		{ yylval.string = strdup(yytext); return T_STRING; }
+
+{comment}	;
+{ws}		;
+{nl}		;
+
+<<EOF>>		{ yyterminate(); }
+
+.		{ return yytext[0]; }
+
+%%
+
+int
+yywrap()
+{
+	return 1;
+}