netfilter: nf_tables: convert built-in tables/chains to chain types

This patch converts built-in tables/chains to chain types that
allows you to deploy customized table and chain configurations from
userspace.

After this patch, you have to specify the chain type when
creating a new chain:

 add chain ip filter output { type filter hook input priority 0; }
                              ^^^^ ------

The existing chain types after this patch are: filter, route and
nat. Note that tables are just containers of chains with no specific
semantics, which is a significant change with regards to iptables.

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

5 files changed, 70 insertions, 122 deletions

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index eb1d56ece36..ae65fe98bfb 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -44,13 +44,13 @@ config NFT_REJECT_IPV4
 	depends on NF_TABLES_IPV4
 	tristate "nf_tables IPv4 reject support"
 
-config NF_TABLE_ROUTE_IPV4
+config NFT_CHAIN_ROUTE_IPV4
 	depends on NF_TABLES_IPV4
-	tristate "IPv4 nf_tables route table support"
+	tristate "IPv4 nf_tables route chain support"
 
-config NF_TABLE_NAT_IPV4
+config NFT_CHAIN_NAT_IPV4
 	depends on NF_TABLES_IPV4
-	tristate "IPv4 nf_tables nat table support"
+	tristate "IPv4 nf_tables nat chain support"
 
 config IP_NF_IPTABLES
 	tristate "IP tables support (required for filtering/masq/NAT)"
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index b2f01cd2cd6..91e0bd71a6d 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -29,8 +29,8 @@ obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
 
 obj-$(CONFIG_NF_TABLES_IPV4) += nf_tables_ipv4.o
 obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o
-obj-$(CONFIG_NF_TABLE_ROUTE_IPV4) += nf_table_route_ipv4.o
-obj-$(CONFIG_NF_TABLE_NAT_IPV4) += nf_table_nat_ipv4.o
+obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV4) += nft_chain_route_ipv4.o
+obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o
 
 # generic IP tables 
 obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o
diff --git a/net/ipv4/netfilter/nf_tables_ipv4.c b/net/ipv4/netfilter/nf_tables_ipv4.c
index 63d0a3bf53d..23525c4c019 100644
--- a/net/ipv4/netfilter/nf_tables_ipv4.c
+++ b/net/ipv4/netfilter/nf_tables_ipv4.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012-2013 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 version 2 as
@@ -41,14 +42,34 @@ static struct nft_af_info nft_af_ipv4 __read_mostly = {
 	},
 };
 
+static struct nf_chain_type filter_ipv4 = {
+	.family		= NFPROTO_IPV4,
+	.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),
+	.fn		= {
+		[NF_INET_LOCAL_IN]	= nft_do_chain,
+		[NF_INET_LOCAL_OUT]	= nft_do_chain,
+		[NF_INET_FORWARD]	= nft_do_chain,
+		[NF_INET_PRE_ROUTING]	= nft_do_chain,
+		[NF_INET_POST_ROUTING]	= nft_do_chain,
+	},
+};
+
 static int __init nf_tables_ipv4_init(void)
 {
+	nft_register_chain_type(&filter_ipv4);
 	return nft_register_afinfo(&nft_af_ipv4);
 }
 
 static void __exit nf_tables_ipv4_exit(void)
 {
 	nft_unregister_afinfo(&nft_af_ipv4);
+	nft_unregister_chain_type(&filter_ipv4);
 }
 
 module_init(nf_tables_ipv4_init);
diff --git a/net/ipv4/netfilter/nf_table_nat_ipv4.c b/net/ipv4/netfilter/nft_chain_nat_ipv4.c
index 2ecce39077a..cd286306be8 100644
--- a/net/ipv4/netfilter/nf_table_nat_ipv4.c
+++ b/net/ipv4/netfilter/nft_chain_nat_ipv4.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012 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 version 2 as
@@ -167,7 +168,7 @@ static struct nft_expr_type nft_nat_type __read_mostly = {
 };
 
 /*
- * NAT table
+ * NAT chains
  */
 
 static unsigned int nf_nat_fn(const struct nf_hook_ops *ops,
@@ -301,115 +302,52 @@ static unsigned int nf_nat_output(const struct nf_hook_ops *ops,
 	return ret;
 }
 
-static struct nft_base_chain nf_chain_nat_prerouting __read_mostly = {
-	.chain	= {
-		.name		= "PREROUTING",
-		.rules		= LIST_HEAD_INIT(nf_chain_nat_prerouting.chain.rules),
-		.flags		= NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
-	},
-	.ops	= {
-		.hook		= nf_nat_prerouting,
-		.owner		= THIS_MODULE,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_PRE_ROUTING,
-		.priority	= NF_IP_PRI_NAT_DST,
-		.priv		= &nf_chain_nat_prerouting.chain,
-	},
-};
-
-static struct nft_base_chain nf_chain_nat_postrouting __read_mostly = {
-	.chain	= {
-		.name		= "POSTROUTING",
-		.rules		= LIST_HEAD_INIT(nf_chain_nat_postrouting.chain.rules),
-		.flags		= NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
-	},
-	.ops	= {
-		.hook		= nf_nat_postrouting,
-		.owner		= THIS_MODULE,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_POST_ROUTING,
-		.priority	= NF_IP_PRI_NAT_SRC,
-		.priv		= &nf_chain_nat_postrouting.chain,
-	},
-};
-
-static struct nft_base_chain nf_chain_nat_output __read_mostly = {
-	.chain	= {
-		.name		= "OUTPUT",
-		.rules		= LIST_HEAD_INIT(nf_chain_nat_output.chain.rules),
-		.flags		= NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
-	},
-	.ops	= {
-		.hook		= nf_nat_output,
-		.owner		= THIS_MODULE,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_LOCAL_OUT,
-		.priority	= NF_IP_PRI_NAT_DST,
-		.priv		= &nf_chain_nat_output.chain,
-	},
-};
-
-static struct nft_base_chain nf_chain_nat_input __read_mostly = {
-	.chain	= {
-		.name		= "INPUT",
-		.rules		= LIST_HEAD_INIT(nf_chain_nat_input.chain.rules),
-		.flags		= NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
-	},
-	.ops	= {
-		.hook		= nf_nat_fn,
-		.owner		= THIS_MODULE,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_LOCAL_IN,
-		.priority	= NF_IP_PRI_NAT_SRC,
-		.priv		= &nf_chain_nat_input.chain,
+struct nf_chain_type nft_chain_nat_ipv4 = {
+	.family		= NFPROTO_IPV4,
+	.name		= "nat",
+	.type		= NFT_CHAIN_T_NAT,
+	.hook_mask	= (1 << NF_INET_PRE_ROUTING) |
+			  (1 << NF_INET_POST_ROUTING) |
+			  (1 << NF_INET_LOCAL_OUT) |
+			  (1 << NF_INET_LOCAL_IN),
+	.fn		= {
+		[NF_INET_PRE_ROUTING]	= nf_nat_prerouting,
+		[NF_INET_POST_ROUTING]	= nf_nat_postrouting,
+		[NF_INET_LOCAL_OUT]	= nf_nat_output,
+		[NF_INET_LOCAL_IN]	= nf_nat_fn,
 	},
+	.me		= THIS_MODULE,
 };
 
-
-static struct nft_table nf_table_nat_ipv4 __read_mostly = {
-	.name	= "nat",
-	.chains	= LIST_HEAD_INIT(nf_table_nat_ipv4.chains),
-};
-
-static int __init nf_table_nat_init(void)
+static int __init nft_chain_nat_init(void)
 {
 	int err;
 
-	list_add_tail(&nf_chain_nat_prerouting.chain.list,
-		      &nf_table_nat_ipv4.chains);
-	list_add_tail(&nf_chain_nat_postrouting.chain.list,
-		      &nf_table_nat_ipv4.chains);
-	list_add_tail(&nf_chain_nat_output.chain.list,
-		      &nf_table_nat_ipv4.chains);
-	list_add_tail(&nf_chain_nat_input.chain.list,
-		      &nf_table_nat_ipv4.chains);
-
-	err = nft_register_table(&nf_table_nat_ipv4, NFPROTO_IPV4);
+	err = nft_register_chain_type(&nft_chain_nat_ipv4);
 	if (err < 0)
-		goto err1;
+		return err;
 
 	err = nft_register_expr(&nft_nat_type);
 	if (err < 0)
-		goto err2;
+		goto err;
 
 	return 0;
 
-err2:
-	nft_unregister_table(&nf_table_nat_ipv4, NFPROTO_IPV4);
-err1:
+err:
+	nft_unregister_chain_type(&nft_chain_nat_ipv4);
 	return err;
 }
 
-static void __exit nf_table_nat_exit(void)
+static void __exit nft_chain_nat_exit(void)
 {
 	nft_unregister_expr(&nft_nat_type);
-	nft_unregister_table(&nf_table_nat_ipv4, AF_INET);
+	nft_unregister_chain_type(&nft_chain_nat_ipv4);
 }
 
-module_init(nf_table_nat_init);
-module_exit(nf_table_nat_exit);
+module_init(nft_chain_nat_init);
+module_exit(nft_chain_nat_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
-MODULE_ALIAS_NFT_TABLE(AF_INET, "nat");
+MODULE_ALIAS_NFT_CHAIN(AF_INET, "nat");
 MODULE_ALIAS_NFT_EXPR("nat");
diff --git a/net/ipv4/netfilter/nf_table_route_ipv4.c b/net/ipv4/netfilter/nft_chain_route_ipv4.c
index 4f257a1ed66..6b84e097b8f 100644
--- a/net/ipv4/netfilter/nf_table_route_ipv4.c
+++ b/net/ipv4/netfilter/nft_chain_route_ipv4.c
@@ -1,5 +1,6 @@
 /*
  * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2012 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 version 2 as
@@ -56,42 +57,30 @@ static unsigned int nf_route_table_hook(const struct nf_hook_ops *ops,
 	return ret;
 }
 
-static struct nft_base_chain nf_chain_route_output __read_mostly = {
-	.chain	= {
-		.name		= "OUTPUT",
-		.rules		= LIST_HEAD_INIT(nf_chain_route_output.chain.rules),
-		.flags		= NFT_BASE_CHAIN | NFT_CHAIN_BUILTIN,
+static struct nf_chain_type nft_chain_route_ipv4 = {
+	.family		= NFPROTO_IPV4,
+	.name		= "route",
+	.type		= NFT_CHAIN_T_ROUTE,
+	.hook_mask	= (1 << NF_INET_LOCAL_OUT),
+	.fn		= {
+		[NF_INET_LOCAL_OUT]	= nf_route_table_hook,
 	},
-	.ops	= {
-		.hook		= nf_route_table_hook,
-		.owner		= THIS_MODULE,
-		.pf		= NFPROTO_IPV4,
-		.hooknum	= NF_INET_LOCAL_OUT,
-		.priority	= NF_IP_PRI_MANGLE,
-		.priv		= &nf_chain_route_output.chain,
-	},
-};
-
-static struct nft_table nf_table_route_ipv4 __read_mostly = {
-	.name	= "route",
-	.chains	= LIST_HEAD_INIT(nf_table_route_ipv4.chains),
+	.me		= THIS_MODULE,
 };
 
-static int __init nf_table_route_init(void)
+static int __init nft_chain_route_init(void)
 {
-	list_add_tail(&nf_chain_route_output.chain.list,
-		      &nf_table_route_ipv4.chains);
-	return nft_register_table(&nf_table_route_ipv4, NFPROTO_IPV4);
+	return nft_register_chain_type(&nft_chain_route_ipv4);
 }
 
-static void __exit nf_table_route_exit(void)
+static void __exit nft_chain_route_exit(void)
 {
-	nft_unregister_table(&nf_table_route_ipv4, NFPROTO_IPV4);
+	nft_unregister_chain_type(&nft_chain_route_ipv4);
 }
 
-module_init(nf_table_route_init);
-module_exit(nf_table_route_exit);
+module_init(nft_chain_route_init);
+module_exit(nft_chain_route_exit);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
-MODULE_ALIAS_NFT_TABLE(AF_INET, "route");
+MODULE_ALIAS_NFT_CHAIN(AF_INET, "route");