netfilter: nf_tables: merge ipv4 and ipv6 nat chain types

Merge the ipv4 and ipv6 nat chain type. This is the last
missing piece which allows to provide inet family support
for nat in a follow patch.

The kconfig knobs for ipv4/ipv6 nat chain are removed, the
nat chain type will be built unconditionally if NFT_NAT
expression is enabled.

Before:
   text	   data	    bss	    dec	    hex	filename
   1576     896       0    2472     9a8 nft_chain_nat_ipv4.ko
   1697     896       0    2593     a21 nft_chain_nat_ipv6.ko

After:
   text	   data	    bss	    dec	    hex	filename
   1832     896       0    2728     aa8 nft_chain_nat.ko
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/ipv4/netfilter/Kconfig

@@ -95,19 +95,6 @@ config NF_REJECT_IPV4
 	default m if NETFILTER_ADVANCED=n
 
 if NF_NAT
-
-if NF_TABLES
-config NFT_CHAIN_NAT_IPV4
-	depends on NF_TABLES_IPV4
-	tristate "IPv4 nf_tables nat chain support"
-	help
-	  This option enables the "nat" chain for IPv4 in nf_tables. This
-	  chain type is used to perform Network Address Translation (NAT)
-	  packet transformations such as the source, destination address and
-	  source and destination ports.
-
-endif # NF_TABLES
-
 config NF_NAT_SNMP_BASIC
 	tristate "Basic SNMP-ALG support"
 	depends on NF_CONNTRACK_SNMP

net/ipv4/netfilter/Makefile

@@ -25,7 +25,6 @@ $(obj)/nf_nat_snmp_basic_main.o: $(obj)/nf_nat_snmp_basic.asn1.h
 obj-$(CONFIG_NF_NAT_SNMP_BASIC) += nf_nat_snmp_basic.o
 
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV4) += nft_chain_route_ipv4.o
-obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o
 obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o
 obj-$(CONFIG_NFT_FIB_IPV4) += nft_fib_ipv4.o
 obj-$(CONFIG_NFT_DUP_IPV4) += nft_dup_ipv4.o

net/ipv6/netfilter/Kconfig

@@ -31,17 +31,6 @@ config NFT_CHAIN_ROUTE_IPV6
 	  fields such as the source, destination, flowlabel, hop-limit and
 	  the packet mark.
 
-if NF_NAT
-
-config NFT_CHAIN_NAT_IPV6
-	tristate "IPv6 nf_tables nat chain support"
-	help
-	  This option enables the "nat" chain for IPv6 in nf_tables. This
-	  chain type is used to perform Network Address Translation (NAT)
-	  packet transformations such as the source, destination address and
-	  source and destination ports.
-endif # NF_NAT
-
 config NFT_REJECT_IPV6
 	select NF_REJECT_IPV6
 	default NFT_REJECT

net/ipv6/netfilter/Makefile

@@ -28,7 +28,6 @@ obj-$(CONFIG_NF_DUP_IPV6) += nf_dup_ipv6.o
 
 # nf_tables
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
-obj-$(CONFIG_NFT_CHAIN_NAT_IPV6) += nft_chain_nat_ipv6.o
 obj-$(CONFIG_NFT_REJECT_IPV6) += nft_reject_ipv6.o
 obj-$(CONFIG_NFT_DUP_IPV6) += nft_dup_ipv6.o
 obj-$(CONFIG_NFT_FIB_IPV6) += nft_fib_ipv6.o

net/ipv6/netfilter/nft_chain_nat_ipv6.c

-/*
- * Copyright (c) 2011 Patrick McHardy <kaber@trash.net>
- * Copyright (c) 2012 Intel Corporation
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms and conditions of the GNU General Public License,
- * version 2, as published by the Free Software Foundation.
- *
- */
-
-#include <linux/module.h>
-#include <linux/init.h>
-#include <linux/list.h>
-#include <linux/skbuff.h>
-#include <linux/ip.h>
-#include <linux/netfilter.h>
-#include <linux/netfilter_ipv6.h>
-#include <linux/netfilter/nf_tables.h>
-#include <net/netfilter/nf_conntrack.h>
-#include <net/netfilter/nf_nat.h>
-#include <net/netfilter/nf_tables.h>
-#include <net/netfilter/nf_tables_ipv6.h>
-#include <net/ipv6.h>
-
-static unsigned int nft_nat_do_chain(void *priv,
-				     struct sk_buff *skb,
-				     const struct nf_hook_state *state)
-{
-	struct nft_pktinfo pkt;
-
-	nft_set_pktinfo(&pkt, skb, state);
-	nft_set_pktinfo_ipv6(&pkt, skb);
-
-	return nft_do_chain(&pkt, priv);
-}
-
-static int nft_nat_ipv6_reg(struct net *net, const struct nf_hook_ops *ops)
-{
-	return nf_nat_ipv6_register_fn(net, ops);
-}
-
-static void nft_nat_ipv6_unreg(struct net *net, const struct nf_hook_ops *ops)
-{
-	nf_nat_ipv6_unregister_fn(net, ops);
-}
-
-static const struct nft_chain_type nft_chain_nat_ipv6 = {
-	.name		= "nat",
-	.type		= NFT_CHAIN_T_NAT,
-	.family		= NFPROTO_IPV6,
-	.owner		= THIS_MODULE,
-	.hook_mask	= (1 << NF_INET_PRE_ROUTING) |
-			  (1 << NF_INET_POST_ROUTING) |
-			  (1 << NF_INET_LOCAL_OUT) |
-			  (1 << NF_INET_LOCAL_IN),
-	.hooks		= {
-		[NF_INET_PRE_ROUTING]	= nft_nat_do_chain,
-		[NF_INET_POST_ROUTING]	= nft_nat_do_chain,
-		[NF_INET_LOCAL_OUT]	= nft_nat_do_chain,
-		[NF_INET_LOCAL_IN]	= nft_nat_do_chain,
-	},
-	.ops_register		= nft_nat_ipv6_reg,
-	.ops_unregister		= nft_nat_ipv6_unreg,
-};
-
-static int __init nft_chain_nat_ipv6_init(void)
-{
-	nft_register_chain_type(&nft_chain_nat_ipv6);
-
-	return 0;
-}
-
-static void __exit nft_chain_nat_ipv6_exit(void)
-{
-	nft_unregister_chain_type(&nft_chain_nat_ipv6);
-}
-
-module_init(nft_chain_nat_ipv6_init);
-module_exit(nft_chain_nat_ipv6_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Tomasz Bursztyka <tomasz.bursztyka@linux.intel.com>");
-MODULE_ALIAS_NFT_CHAIN(AF_INET6, "nat");

net/netfilter/Kconfig

@@ -550,6 +550,7 @@ config NFT_REDIR
 config NFT_NAT
 	depends on NF_CONNTRACK
 	select NF_NAT
+	depends on NF_TABLES_IPV4 || NF_TABLES_IPV6
 	tristate "Netfilter nf_tables nat module"
 	help
 	  This option adds the "nat" expression that you can use to perform

net/netfilter/Makefile

@@ -110,6 +110,8 @@ obj-$(CONFIG_NFT_OSF)		+= nft_osf.o
 obj-$(CONFIG_NFT_TPROXY)	+= nft_tproxy.o
 obj-$(CONFIG_NFT_XFRM)		+= nft_xfrm.o
 
+obj-$(CONFIG_NFT_NAT)		+= nft_chain_nat.o
+
 # nf_tables netdev
 obj-$(CONFIG_NFT_DUP_NETDEV)	+= nft_dup_netdev.o
 obj-$(CONFIG_NFT_FWD_NETDEV)	+= nft_fwd_netdev.o

net/ipv4/netfilter/nft_chain_nat_ipv4.c → net/netfilter/nft_chain_nat.c

-/*
- * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
- * Copyright (c) 2012 Pablo Neira Ayuso <pablo@netfilter.org>
- * Copyright (c) 2012 Intel Corporation
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
- * Development of this code funded by Astaro AG (http://www.astaro.com/)
- */
+// SPDX-License-Identifier: GPL-2.0
 
 #include <linux/module.h>
-#include <linux/init.h>
-#include <linux/list.h>
-#include <linux/skbuff.h>
-#include <linux/ip.h>
-#include <linux/netfilter.h>
-#include <linux/netfilter_ipv4.h>
 #include <linux/netfilter/nf_tables.h>
-#include <net/netfilter/nf_conntrack.h>
 #include <net/netfilter/nf_nat.h>
 #include <net/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables_ipv4.h>
-#include <net/ip.h>
+#include <net/netfilter/nf_tables_ipv6.h>
 
-static unsigned int nft_nat_do_chain(void *priv,
-				     struct sk_buff *skb,
+static unsigned int nft_nat_do_chain(void *priv, struct sk_buff *skb,
 				     const struct nf_hook_state *state)
 {
 	struct nft_pktinfo pkt;
 
 	nft_set_pktinfo(&pkt, skb, state);
+
+	switch (state->pf) {
+#ifdef CONFIG_NF_TABLES_IPV4
+	case NFPROTO_IPV4:
 		nft_set_pktinfo_ipv4(&pkt, skb);
+		break;
+#endif
+#ifdef CONFIG_NF_TABLES_IPV6
+	case NFPROTO_IPV6:
+		nft_set_pktinfo_ipv6(&pkt, skb);
+		break;
+#endif
+	default:
+		break;
+	}
 
 	return nft_do_chain(&pkt, priv);
 }
 
-static int nft_nat_ipv4_reg(struct net *net, const struct nf_hook_ops *ops)
-{
-	return nf_nat_ipv4_register_fn(net, ops);
-}
-
-static void nft_nat_ipv4_unreg(struct net *net, const struct nf_hook_ops *ops)
-{
-	nf_nat_ipv4_unregister_fn(net, ops);
-}
-
+#ifdef CONFIG_NF_TABLES_IPV4
 static const struct nft_chain_type nft_chain_nat_ipv4 = {
 	.name		= "nat",
 	.type		= NFT_CHAIN_T_NAT,
@@ -61,25 +48,61 @@ static const struct nft_chain_type nft_chain_nat_ipv4 = {
 		[NF_INET_LOCAL_OUT]	= nft_nat_do_chain,
 		[NF_INET_LOCAL_IN]	= nft_nat_do_chain,
 	},
-	.ops_register = nft_nat_ipv4_reg,
-	.ops_unregister = nft_nat_ipv4_unreg,
+	.ops_register = nf_nat_ipv4_register_fn,
+	.ops_unregister = nf_nat_ipv4_unregister_fn,
+};
+#endif
+
+#ifdef CONFIG_NF_TABLES_IPV6
+static const struct nft_chain_type nft_chain_nat_ipv6 = {
+	.name		= "nat",
+	.type		= NFT_CHAIN_T_NAT,
+	.family		= NFPROTO_IPV6,
+	.owner		= THIS_MODULE,
+	.hook_mask	= (1 << NF_INET_PRE_ROUTING) |
+			  (1 << NF_INET_POST_ROUTING) |
+			  (1 << NF_INET_LOCAL_OUT) |
+			  (1 << NF_INET_LOCAL_IN),
+	.hooks		= {
+		[NF_INET_PRE_ROUTING]	= nft_nat_do_chain,
+		[NF_INET_POST_ROUTING]	= nft_nat_do_chain,
+		[NF_INET_LOCAL_OUT]	= nft_nat_do_chain,
+		[NF_INET_LOCAL_IN]	= nft_nat_do_chain,
+	},
+	.ops_register		= nf_nat_ipv6_register_fn,
+	.ops_unregister		= nf_nat_ipv6_unregister_fn,
 };
+#endif
 
 static int __init nft_chain_nat_init(void)
 {
+#ifdef CONFIG_NF_TABLES_IPV6
+	nft_register_chain_type(&nft_chain_nat_ipv6);
+#endif
+#ifdef CONFIG_NF_TABLES_IPV4
 	nft_register_chain_type(&nft_chain_nat_ipv4);
+#endif
 
 	return 0;
 }
 
 static void __exit nft_chain_nat_exit(void)
 {
+#ifdef CONFIG_NF_TABLES_IPV4
 	nft_unregister_chain_type(&nft_chain_nat_ipv4);
+#endif
+#ifdef CONFIG_NF_TABLES_IPV6
+	nft_unregister_chain_type(&nft_chain_nat_ipv6);
+#endif
 }
 
 module_init(nft_chain_nat_init);
 module_exit(nft_chain_nat_exit);
 
 MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+#ifdef CONFIG_NF_TABLES_IPV4
 MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat");
+#endif
+#ifdef CONFIG_NF_TABLES_IPV6
+MODULE_ALIAS_NFT_CHAIN(AF_INET6, "nat");
+#endif