netfilter: nf_tables: make counter support built-in

Make counter support built-in to allow for direct call in case of
CONFIG_RETPOLINE.

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

include/net/netfilter/nf_tables_core.h

@@ -7,6 +7,7 @@
 
 extern struct nft_expr_type nft_imm_type;
 extern struct nft_expr_type nft_cmp_type;
+extern struct nft_expr_type nft_counter_type;
 extern struct nft_expr_type nft_lookup_type;
 extern struct nft_expr_type nft_bitwise_type;
 extern struct nft_expr_type nft_byteorder_type;
@@ -21,6 +22,7 @@ extern struct nft_expr_type nft_last_type;
 #ifdef CONFIG_NETWORK_SECMARK
 extern struct nft_object_type nft_secmark_obj_type;
 #endif
+extern struct nft_object_type nft_counter_obj_type;
 
 int nf_tables_core_module_init(void);
 void nf_tables_core_module_exit(void);
@@ -120,6 +122,8 @@ bool nft_pipapo_lookup(const struct net *net, const struct nft_set *set,
 bool nft_pipapo_avx2_lookup(const struct net *net, const struct nft_set *set,
 			    const u32 *key, const struct nft_set_ext **ext);
 
+void nft_counter_init_seqcount(void);
+
 struct nft_expr;
 struct nft_regs;
 struct nft_pktinfo;
@@ -143,4 +147,6 @@ void nft_dynset_eval(const struct nft_expr *expr,
 		     struct nft_regs *regs, const struct nft_pktinfo *pkt);
 void nft_rt_get_eval(const struct nft_expr *expr,
 		     struct nft_regs *regs, const struct nft_pktinfo *pkt);
+void nft_counter_eval(const struct nft_expr *expr, struct nft_regs *regs,
+                      const struct nft_pktinfo *pkt);
 #endif /* _NET_NF_TABLES_CORE_H */

net/netfilter/Kconfig

@@ -515,12 +515,6 @@ config NFT_FLOW_OFFLOAD
 	  This option adds the "flow_offload" expression that you can use to
 	  choose what flows are placed into the hardware.
 
-config NFT_COUNTER
-	tristate "Netfilter nf_tables counter module"
-	help
-	  This option adds the "counter" expression that you can use to
-	  include packet and byte counters in a rule.
-
 config NFT_CONNLIMIT
 	tristate "Netfilter nf_tables connlimit module"
 	depends on NF_CONNTRACK

net/netfilter/Makefile

@@ -75,7 +75,7 @@ nf_tables-objs := nf_tables_core.o nf_tables_api.o nft_chain_filter.o \
 		  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_last.o \
-		  nft_chain_route.o nf_tables_offload.o \
+		  nft_counter.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
 
@@ -100,7 +100,6 @@ obj-$(CONFIG_NFT_REJECT) 	+= nft_reject.o
 obj-$(CONFIG_NFT_REJECT_INET)	+= nft_reject_inet.o
 obj-$(CONFIG_NFT_REJECT_NETDEV)	+= nft_reject_netdev.o
 obj-$(CONFIG_NFT_TUNNEL)	+= nft_tunnel.o
-obj-$(CONFIG_NFT_COUNTER)	+= nft_counter.o
 obj-$(CONFIG_NFT_LOG)		+= nft_log.o
 obj-$(CONFIG_NFT_MASQ)		+= nft_masq.o
 obj-$(CONFIG_NFT_REDIR)		+= nft_redir.o

net/netfilter/nf_tables_core.c

@@ -169,6 +169,7 @@ static void expr_call_ops_eval(const struct nft_expr *expr,
 
 	X(e, nft_payload_eval);
 	X(e, nft_cmp_eval);
+	X(e, nft_counter_eval);
 	X(e, nft_meta_get_eval);
 	X(e, nft_lookup_eval);
 	X(e, nft_range_eval);
@@ -292,18 +293,22 @@ static struct nft_expr_type *nft_basic_types[] = {
 	&nft_rt_type,
 	&nft_exthdr_type,
 	&nft_last_type,
+	&nft_counter_type,
 };
 
 static struct nft_object_type *nft_basic_objects[] = {
 #ifdef CONFIG_NETWORK_SECMARK
 	&nft_secmark_obj_type,
 #endif
+	&nft_counter_obj_type,
 };
 
 int __init nf_tables_core_module_init(void)
 {
 	int err, i, j = 0;
 
+	nft_counter_init_seqcount();
+
 	for (i = 0; i < ARRAY_SIZE(nft_basic_objects); i++) {
 		err = nft_register_obj(nft_basic_objects[i]);
 		if (err)

net/netfilter/nft_counter.c

@@ -13,6 +13,7 @@
 #include <linux/netfilter.h>
 #include <linux/netfilter/nf_tables.h>
 #include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
 #include <net/netfilter/nf_tables_offload.h>
 
 struct nft_counter {
@@ -174,7 +175,7 @@ static const struct nla_policy nft_counter_policy[NFTA_COUNTER_MAX + 1] = {
 	[NFTA_COUNTER_BYTES]	= { .type = NLA_U64 },
 };
 
-static struct nft_object_type nft_counter_obj_type;
+struct nft_object_type nft_counter_obj_type;
 static const struct nft_object_ops nft_counter_obj_ops = {
 	.type		= &nft_counter_obj_type,
 	.size		= sizeof(struct nft_counter_percpu_priv),
@@ -184,17 +185,16 @@ static const struct nft_object_ops nft_counter_obj_ops = {
 	.dump		= nft_counter_obj_dump,
 };
 
-static struct nft_object_type nft_counter_obj_type __read_mostly = {
+struct nft_object_type nft_counter_obj_type __read_mostly = {
 	.type		= NFT_OBJECT_COUNTER,
 	.ops		= &nft_counter_obj_ops,
 	.maxattr	= NFTA_COUNTER_MAX,
 	.policy		= nft_counter_policy,
 	.owner		= THIS_MODULE,
 };
 
-static void nft_counter_eval(const struct nft_expr *expr,
-			     struct nft_regs *regs,
-			     const struct nft_pktinfo *pkt)
+void nft_counter_eval(const struct nft_expr *expr, struct nft_regs *regs,
+		      const struct nft_pktinfo *pkt)
 {
 	struct nft_counter_percpu_priv *priv = nft_expr_priv(expr);
 
@@ -275,7 +275,15 @@ static void nft_counter_offload_stats(struct nft_expr *expr,
 	preempt_enable();
 }
 
-static struct nft_expr_type nft_counter_type;
+void nft_counter_init_seqcount(void)
+{
+	int cpu;
+
+	for_each_possible_cpu(cpu)
+		seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
+}
+
+struct nft_expr_type nft_counter_type;
 static const struct nft_expr_ops nft_counter_ops = {
 	.type		= &nft_counter_type,
 	.size		= NFT_EXPR_SIZE(sizeof(struct nft_counter_percpu_priv)),
@@ -289,47 +297,11 @@ static const struct nft_expr_ops nft_counter_ops = {
 	.offload_stats	= nft_counter_offload_stats,
 };
 
-static struct nft_expr_type nft_counter_type __read_mostly = {
+struct nft_expr_type nft_counter_type __read_mostly = {
 	.name		= "counter",
 	.ops		= &nft_counter_ops,
 	.policy		= nft_counter_policy,
 	.maxattr	= NFTA_COUNTER_MAX,
 	.flags		= NFT_EXPR_STATEFUL,
 	.owner		= THIS_MODULE,
 };
-
-static int __init nft_counter_module_init(void)
-{
-	int cpu, err;
-
-	for_each_possible_cpu(cpu)
-		seqcount_init(per_cpu_ptr(&nft_counter_seq, cpu));
-
-	err = nft_register_obj(&nft_counter_obj_type);
-	if (err < 0)
-		return err;
-
-	err = nft_register_expr(&nft_counter_type);
-	if (err < 0)
-		goto err1;
-
-	return 0;
-err1:
-	nft_unregister_obj(&nft_counter_obj_type);
-	return err;
-}
-
-static void __exit nft_counter_module_exit(void)
-{
-	nft_unregister_expr(&nft_counter_type);
-	nft_unregister_obj(&nft_counter_obj_type);
-}
-
-module_init(nft_counter_module_init);
-module_exit(nft_counter_module_exit);
-
-MODULE_LICENSE("GPL");
-MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
-MODULE_ALIAS_NFT_EXPR("counter");
-MODULE_ALIAS_NFT_OBJ(NFT_OBJECT_COUNTER);
-MODULE_DESCRIPTION("nftables counter rule support");