netfilter: nf_tables: add "inet" table for IPv4/IPv6

This patch adds a new table family and a new filter chain that you can
use to attach IPv4 and IPv6 rules. This should help to simplify
rule-set maintainance in dual-stack setups.

Signed-off-by: Patrick McHardy <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

include/net/netfilter/nf_tables_ipv4.h

···
 	pkt->xt.fragoff = ntohs(ip->frag_off) & IP_OFFSET;
 }
 
+extern struct nft_af_info nft_af_ipv4;
+
 #endif

include/net/netfilter/nf_tables_ipv6.h

···
 	return 0;
 }
 
+extern struct nft_af_info nft_af_ipv6;
+
 #endif

include/net/netns/nftables.h

···
 	struct list_head	commit_list;
 	struct nft_af_info	*ipv4;
 	struct nft_af_info	*ipv6;
+	struct nft_af_info	*inet;
 	struct nft_af_info	*arp;
 	struct nft_af_info	*bridge;
 	u8			gencursor;

include/uapi/linux/netfilter.h

···
 
 enum {
 	NFPROTO_UNSPEC =  0,
+	NFPROTO_INET   =  1,
 	NFPROTO_IPV4   =  2,
 	NFPROTO_ARP    =  3,
 	NFPROTO_BRIDGE =  7,

net/ipv4/netfilter/nf_tables_ipv4.c

···
 	return nft_do_chain_ipv4(ops, skb, in, out, okfn);
 }
 
-static struct nft_af_info nft_af_ipv4 __read_mostly = {
+struct nft_af_info nft_af_ipv4 __read_mostly = {
 	.family		= NFPROTO_IPV4,
 	.nhooks		= NF_INET_NUMHOOKS,
 	.owner		= THIS_MODULE,
···
 		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv4,
 	},
 };
+EXPORT_SYMBOL_GPL(nft_af_ipv4);
 
 static int nf_tables_ipv4_init_net(struct net *net)
 {

net/ipv6/netfilter/nf_tables_ipv6.c

···
 	return nft_do_chain_ipv6(ops, skb, in, out, okfn);
 }
 
-static struct nft_af_info nft_af_ipv6 __read_mostly = {
+struct nft_af_info nft_af_ipv6 __read_mostly = {
 	.family		= NFPROTO_IPV6,
 	.nhooks		= NF_INET_NUMHOOKS,
 	.owner		= THIS_MODULE,
···
 		[NF_INET_POST_ROUTING]	= nft_do_chain_ipv6,
 	},
 };
+EXPORT_SYMBOL_GPL(nft_af_ipv6);
 
 static int nf_tables_ipv6_init_net(struct net *net)
 {

net/netfilter/Kconfig

···
 
 	  To compile it as a module, choose M here.
 
+config NF_TABLES_INET
+	depends on NF_TABLES
+	select NF_TABLES_IPV4
+	select NF_TABLES_IPV6
+	tristate "Netfilter nf_tables mixed IPv4/IPv6 tables support"
+	help
+	  This option enables support for a mixed IPv4/IPv6 "inet" table.
+
 config NFT_EXTHDR
 	depends on NF_TABLES
 	tristate "Netfilter nf_tables IPv6 exthdr module"

net/netfilter/Makefile

···
 nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
 
 obj-$(CONFIG_NF_TABLES)		+= nf_tables.o
+obj-$(CONFIG_NF_TABLES_INET)	+= nf_tables_inet.o
 obj-$(CONFIG_NFT_COMPAT)	+= nft_compat.o
 obj-$(CONFIG_NFT_EXTHDR)	+= nft_exthdr.o
 obj-$(CONFIG_NFT_META)		+= nft_meta.o

net/netfilter/nf_tables_inet.c

···
+/*
+ * Copyright (c) 2012-2014 Patrick McHardy <[e-mail]>
+ *
+ * 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.
+ */
+
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/ip.h>
+#include <linux/netfilter_ipv4.h>
+#include <linux/netfilter_ipv6.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_ipv4.h>
+#include <net/netfilter/nf_tables_ipv6.h>
+#include <net/ip.h>
+
+static void nft_inet_hook_ops_init(struct nf_hook_ops *ops, unsigned int n)
+{
+	struct nft_af_info *afi;
+
+	if (n == 1)
+		afi = &nft_af_ipv4;
+	else
+		afi = &nft_af_ipv6;
+
+	ops->pf = afi->family;
+	if (afi->hooks[ops->hooknum])
+		ops->hook = afi->hooks[ops->hooknum];
+}
+
+static struct nft_af_info nft_af_inet __read_mostly = {
+	.family		= NFPROTO_INET,
+	.nhooks		= NF_INET_NUMHOOKS,
+	.owner		= THIS_MODULE,
+	.nops		= 2,
+	.hook_ops_init	= nft_inet_hook_ops_init,
+};
+
+static int __net_init nf_tables_inet_init_net(struct net *net)
+{
+	net->nft.inet = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
+	if (net->nft.inet == NULL)
+		return -ENOMEM;
+	memcpy(net->nft.inet, &nft_af_inet, sizeof(nft_af_inet));
+
+	if (nft_register_afinfo(net, net->nft.inet) < 0)
+		goto err;
+
+	return 0;
+
+err:
+	kfree(net->nft.inet);
+	return -ENOMEM;
+}
+
+static void __net_exit nf_tables_inet_exit_net(struct net *net)
+{
+	nft_unregister_afinfo(net->nft.inet);
+	kfree(net->nft.inet);
+}
+
+static struct pernet_operations nf_tables_inet_net_ops = {
+	.init	= nf_tables_inet_init_net,
+	.exit	= nf_tables_inet_exit_net,
+};
+
+static struct nf_chain_type filter_inet = {
+	.family		= NFPROTO_INET,
+	.name		= "filter",
+	.type		= NFT_CHAIN_T_DEFAULT,
+	.hook_mask	= (1 << NF_INET_LOCAL_IN) |
+			  (1 << NF_INET_LOCAL_OUT) |
+			  (1 << NF_INET_FORWARD) |
+			  (1 << NF_INET_PRE_ROUTING) |
+			  (1 << NF_INET_POST_ROUTING),
+};
+
+static int __init nf_tables_inet_init(void)
+{
+	nft_register_chain_type(&filter_inet);
+	return register_pernet_subsys(&nf_tables_inet_net_ops);
+}
+
+static void __exit nf_tables_inet_exit(void)
+{
+	unregister_pernet_subsys(&nf_tables_inet_net_ops);
+	nft_unregister_chain_type(&filter_inet);
+}
+
+module_init(nf_tables_inet_init);
+module_exit(nf_tables_inet_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <[e-mail]>");
+MODULE_ALIAS_NFT_FAMILY(1);