netfilter: nf_tables: make sets built-in

Placing nftables set support in an extra module is pointless:

1. nf_tables needs dynamic registeration interface for sake of one module
2. nft heavily relies on sets, e.g. even simple rule like
"nft ... tcp dport { 80, 443 }" will not work with _SETS=n.

IOW, either nftables isn't used or both nf_tables and nf_tables_set
modules are needed anyway.

With extra module:
307K net/netfilter/nf_tables.ko
79K net/netfilter/nf_tables_set.ko

text data bss dec filename
146416 3072 545 150033 nf_tables.ko
35496 1817 0 37313 nf_tables_set.ko

This patch:
373K net/netfilter/nf_tables.ko

178563 4049 545 183157 nf_tables.ko

Signed-off-by: Florian Westphal <[e-mail]>
Signed-off-by: Pablo Neira Ayuso <[e-mail]>

include/net/netfilter/nf_tables.h

···
 };
 #define to_set_type(o) container_of(o, struct nft_set_type, ops)
 
-int nft_register_set(struct nft_set_type *type);
-void nft_unregister_set(struct nft_set_type *type);
-
 /**
  * 	struct nft_set - nf_tables set instance
  *
···
 
 #define MODULE_ALIAS_NFT_EXPR(name) \
 	MODULE_ALIAS("nft-expr-" name)
-
-#define MODULE_ALIAS_NFT_SET() \
-	MODULE_ALIAS("nft-set")
 
 #define MODULE_ALIAS_NFT_OBJ(type) \
 	MODULE_ALIAS("nft-obj-" __stringify(type))

net/netfilter/Kconfig

···
 	  To compile it as a module, choose M here.
 
 if NF_TABLES
-
-config NF_TABLES_SET
-	tristate "Netfilter nf_tables set infrastructure"
-	help
-	  This option enables the nf_tables set infrastructure that allows to
-	  look up for elements in a set and to build one-way mappings between
-	  matchings and actions.
-
 config NF_TABLES_INET
 	depends on IPV6
 	select NF_TABLES_IPV4

net/netfilter/Makefile

···
 		  nf_tables_trace.o nft_immediate.o nft_cmp.o nft_range.o \
 		  nft_bitwise.o nft_byteorder.o nft_payload.o nft_lookup.o \
 		  nft_dynset.o nft_meta.o nft_rt.o nft_exthdr.o \
-		  nft_chain_route.o nf_tables_offload.o
-
-nf_tables_set-objs := nf_tables_set_core.o \
-		      nft_set_hash.o nft_set_bitmap.o nft_set_rbtree.o \
-		      nft_set_pipapo.o
+		  nft_chain_route.o nf_tables_offload.o \
+		  nft_set_hash.o nft_set_bitmap.o nft_set_rbtree.o \
+		  nft_set_pipapo.o
 
 obj-$(CONFIG_NF_TABLES)		+= nf_tables.o
-obj-$(CONFIG_NF_TABLES_SET)	+= nf_tables_set.o
 obj-$(CONFIG_NFT_COMPAT)	+= nft_compat.o
 obj-$(CONFIG_NFT_CONNLIMIT)	+= nft_connlimit.o
 obj-$(CONFIG_NFT_NUMGEN)	+= nft_numgen.o

net/netfilter/nf_tables_api.c

···
 /*
  * Sets
  */
-
-static LIST_HEAD(nf_tables_set_types);
-
-int nft_register_set(struct nft_set_type *type)
-{
-	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	list_add_tail_rcu(&type->list, &nf_tables_set_types);
-	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
-	return 0;
-}
-EXPORT_SYMBOL_GPL(nft_register_set);
-
-void nft_unregister_set(struct nft_set_type *type)
-{
-	nfnl_lock(NFNL_SUBSYS_NFTABLES);
-	list_del_rcu(&type->list);
-	nfnl_unlock(NFNL_SUBSYS_NFTABLES);
-}
-EXPORT_SYMBOL_GPL(nft_unregister_set);
+static const struct nft_set_type *nft_set_types[] = {
+	&nft_set_hash_fast_type,
+	&nft_set_hash_type,
+	&nft_set_rhash_type,
+	&nft_set_bitmap_type,
+	&nft_set_rbtree_type,
+	&nft_set_pipapo_type,
+};
 
 #define NFT_SET_FEATURES	(NFT_SET_INTERVAL | NFT_SET_MAP | \
 				 NFT_SET_TIMEOUT | NFT_SET_OBJECT | \
···
 	struct nft_set_estimate est, best;
 	const struct nft_set_type *type;
 	u32 flags = 0;
+	int i;
 
 	lockdep_assert_held(&ctx->net->nft.commit_mutex);
 	lockdep_nfnl_nft_mutex_not_held();
-#ifdef CONFIG_MODULES
-	if (list_empty(&nf_tables_set_types)) {
-		if (nft_request_module(ctx->net, "nft-set") == -EAGAIN)
-			return ERR_PTR(-EAGAIN);
-	}
-#endif
+
 	if (nla[NFTA_SET_FLAGS] != NULL)
 		flags = ntohl(nla_get_be32(nla[NFTA_SET_FLAGS]));
 
···
 	best.lookup = ~0;
 	best.space  = ~0;
 
-	list_for_each_entry(type, &nf_tables_set_types, list) {
+	for (i = 0; i < ARRAY_SIZE(nft_set_types); i++) {
+		type = nft_set_types[i];
 		ops = &type->ops;
 
 		if (!nft_set_ops_candidate(type, flags))
···
 		.align	= __alignof__(u32),
 	},
 };
-EXPORT_SYMBOL_GPL(nft_set_ext_types);
 
 /*
  * Set elements
···
 		nft_set_elem_destroy(gcb->head.set, gcb->elems[i], true);
 	kfree(gcb);
 }
-EXPORT_SYMBOL_GPL(nft_set_gc_batch_release);
 
 struct nft_set_gc_batch *nft_set_gc_batch_alloc(const struct nft_set *set,
 						gfp_t gfp)
···
 	gcb->head.set = set;
 	return gcb;
 }
-EXPORT_SYMBOL_GPL(nft_set_gc_batch_alloc);
 
 /*
  * Stateful objects

net/netfilter/nf_tables_set_core.c

···
-/* SPDX-License-Identifier: GPL-2.0 */
-#include <linux/module.h>
-#include <net/netfilter/nf_tables_core.h>
-
-static int __init nf_tables_set_module_init(void)
-{
-	nft_register_set(&nft_set_hash_fast_type);
-	nft_register_set(&nft_set_hash_type);
-	nft_register_set(&nft_set_rhash_type);
-	nft_register_set(&nft_set_bitmap_type);
-	nft_register_set(&nft_set_rbtree_type);
-	nft_register_set(&nft_set_pipapo_type);
-
-	return 0;
-}
-
-static void __exit nf_tables_set_module_exit(void)
-{
-	nft_unregister_set(&nft_set_pipapo_type);
-	nft_unregister_set(&nft_set_rbtree_type);
-	nft_unregister_set(&nft_set_bitmap_type);
-	nft_unregister_set(&nft_set_rhash_type);
-	nft_unregister_set(&nft_set_hash_type);
-	nft_unregister_set(&nft_set_hash_fast_type);
-}
-
-module_init(nf_tables_set_module_init);
-module_exit(nf_tables_set_module_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_ALIAS_NFT_SET();