From b65a70131d0d38844be12235270eebaa9d2f5a4d Mon Sep 17 00:00:00 2001
From: Pablo Neira Ayuso <pablo@netfilter.org>
Date: Tue, 12 Jul 2016 22:04:17 +0200
Subject: src: add xt compat support

At compilation time, you have to pass this option.

  # ./configure --with-xtables

And libxtables needs to be installed in your system.

This patch allows to list a ruleset containing xt extensions loaded
through iptables-compat-restore tool.

Example:

$ iptables-save > ruleset

$ cat ruleset
*filter
:INPUT ACCEPT [0:0]
:FORWARD ACCEPT [0:0]
:OUTPUT ACCEPT [0:0]
-A INPUT -p tcp -m multiport --dports 80,81 -j REJECT
COMMIT

$ sudo iptables-compat-restore ruleset

$ sudo nft list rulseset
table ip filter {
    chain INPUT {
        type filter hook input priority 0; policy accept;
        ip protocol tcp tcp dport { 80,81} counter packets 0 bytes 0 reject
    }

    chain FORWARD {
        type filter hook forward priority 0; policy drop;
    }

    chain OUTPUT {
        type filter hook output priority 0; policy accept;
    }
}

A translation of the extension is shown if this is available. In other
case, match or target definition is preceded by a hash. For example,
classify target has not translation:

$ sudo nft list chain mangle POSTROUTING
table ip mangle {
    chain POSTROUTING {
        type filter hook postrouting priority -150; policy accept;
        ip protocol tcp tcp dport 80 counter packets 0 bytes 0 # CLASSIFY set 20:10
                                                              ^^^
    }
}

If the whole ruleset is translatable, the users can (re)load it using
"nft -f" and get nft native support for all their rules.

This patch is joint work by the authors listed below.

Signed-off-by: Arturo Borrero Gonzalez <arturo.borrero.glez@gmail.com>
Signed-off-by: Pablo M. Bermudo Garay <pablombg@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 include/xt.h | 39 +++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 include/xt.h

(limited to 'include/xt.h')

diff --git a/include/xt.h b/include/xt.h
new file mode 100644
index 00000000..753511e6
--- /dev/null
+++ b/include/xt.h
@@ -0,0 +1,39 @@
+#ifndef _NFT_XT_H_
+#define _NFT_XT_H_
+
+struct netlink_linearize_ctx;
+struct netlink_parse_ctx;
+struct nftnl_expr;
+struct rule_pp_ctx;
+struct rule;
+
+#ifdef HAVE_LIBXTABLES
+void xt_stmt_xlate(const struct stmt *stmt);
+void xt_stmt_release(const struct stmt *stmt);
+
+void netlink_parse_target(struct netlink_parse_ctx *ctx,
+			  const struct location *loc,
+			  const struct nftnl_expr *nle);
+void netlink_parse_match(struct netlink_parse_ctx *ctx,
+			 const struct location *loc,
+			 const struct nftnl_expr *nle);
+void stmt_xt_postprocess(struct rule_pp_ctx *rctx, struct stmt *stmt,
+			 struct rule *rule);
+#else
+static inline void xt_stmt_xlate(const struct stmt *stmt) {}
+static inline void xt_stmt_release(const struct stmt *stmt) {}
+
+#include <erec.h>
+
+static inline void netlink_parse_target(struct netlink_parse_ctx *ctx,
+					const struct location *loc,
+					const struct nftnl_expr *nle) {}
+static inline void netlink_parse_match(struct netlink_parse_ctx *ctx,
+				       const struct location *loc,
+				       const struct nftnl_expr *nle) {}
+static inline void stmt_xt_postprocess(struct rule_pp_ctx *rctx,
+				       struct stmt *stmt, struct rule *rule) {}
+
+#endif
+
+#endif /* _NFT_XT_H_ */
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