netfilter: nf_tables: add reject module for NFPROTO_INET

Add a reject module for NFPROTO_INET. It does nothing but dispatch
to the AF-specific modules based on the hook family.

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

include/net/netfilter/nft_reject.h

···
 
 int nft_reject_dump(struct sk_buff *skb, const struct nft_expr *expr);
 
+void nft_reject_ipv4_eval(const struct nft_expr *expr,
+			  struct nft_data data[NFT_REG_MAX + 1],
+			  const struct nft_pktinfo *pkt);
+
+void nft_reject_ipv6_eval(const struct nft_expr *expr,
+			  struct nft_data data[NFT_REG_MAX + 1],
+			  const struct nft_pktinfo *pkt);
+
 #endif

net/ipv4/netfilter/nft_reject_ipv4.c

···
 #include <net/netfilter/ipv4/nf_reject.h>
 #include <net/netfilter/nft_reject.h>
 
-static void nft_reject_ipv4_eval(const struct nft_expr *expr,
-				 struct nft_data data[NFT_REG_MAX + 1],
-				 const struct nft_pktinfo *pkt)
+void nft_reject_ipv4_eval(const struct nft_expr *expr,
+			  struct nft_data data[NFT_REG_MAX + 1],
+			  const struct nft_pktinfo *pkt)
 {
 	struct nft_reject *priv = nft_expr_priv(expr);
 
···
 
 	data[NFT_REG_VERDICT].verdict = NF_DROP;
 }
+EXPORT_SYMBOL_GPL(nft_reject_ipv4_eval);
 
 static struct nft_expr_type nft_reject_ipv4_type;
 static const struct nft_expr_ops nft_reject_ipv4_ops = {

net/ipv6/netfilter/nft_reject_ipv6.c

···
 #include <net/netfilter/nft_reject.h>
 #include <net/netfilter/ipv6/nf_reject.h>
 
-static void nft_reject_ipv6_eval(const struct nft_expr *expr,
-				 struct nft_data data[NFT_REG_MAX + 1],
-				 const struct nft_pktinfo *pkt)
+void nft_reject_ipv6_eval(const struct nft_expr *expr,
+			  struct nft_data data[NFT_REG_MAX + 1],
+			  const struct nft_pktinfo *pkt)
 {
 	struct nft_reject *priv = nft_expr_priv(expr);
 	struct net *net = dev_net((pkt->in != NULL) ? pkt->in : pkt->out);
···
 
 	data[NFT_REG_VERDICT].verdict = NF_DROP;
 }
+EXPORT_SYMBOL_GPL(nft_reject_ipv6_eval);
 
 static struct nft_expr_type nft_reject_ipv6_type;
 static const struct nft_expr_ops nft_reject_ipv6_ops = {

net/netfilter/Kconfig

···
 	  explicitly deny and notify via TCP reset/ICMP informational errors
 	  unallowed traffic.
 
+config NFT_REJECT_INET
+	depends on NF_TABLES_INET
+	default NFT_REJECT
+	tristate
+
 config NFT_COMPAT
 	depends on NF_TABLES
 	depends on NETFILTER_XTABLES

net/netfilter/Makefile

···
 obj-$(CONFIG_NFT_NAT)		+= nft_nat.o
 obj-$(CONFIG_NFT_QUEUE)		+= nft_queue.o
 obj-$(CONFIG_NFT_REJECT) 	+= nft_reject.o
+obj-$(CONFIG_NFT_REJECT_INET)	+= nft_reject_inet.o
 obj-$(CONFIG_NFT_RBTREE)	+= nft_rbtree.o
 obj-$(CONFIG_NFT_HASH)		+= nft_hash.o
 obj-$(CONFIG_NFT_COUNTER)	+= nft_counter.o

net/netfilter/nft_reject_inet.c

···
+/*
+ * Copyright (c) 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/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nft_reject.h>
+
+static void nft_reject_inet_eval(const struct nft_expr *expr,
+				 struct nft_data data[NFT_REG_MAX + 1],
+				 const struct nft_pktinfo *pkt)
+{
+	switch (pkt->ops->pf) {
+	case NFPROTO_IPV4:
+		nft_reject_ipv4_eval(expr, data, pkt);
+	case NFPROTO_IPV6:
+		nft_reject_ipv6_eval(expr, data, pkt);
+	}
+}
+
+static struct nft_expr_type nft_reject_inet_type;
+static const struct nft_expr_ops nft_reject_inet_ops = {
+	.type		= &nft_reject_inet_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_reject)),
+	.eval		= nft_reject_inet_eval,
+	.init		= nft_reject_init,
+	.dump		= nft_reject_dump,
+};
+
+static struct nft_expr_type nft_reject_inet_type __read_mostly = {
+	.family		= NFPROTO_INET,
+	.name		= "reject",
+	.ops		= &nft_reject_inet_ops,
+	.policy		= nft_reject_policy,
+	.maxattr	= NFTA_REJECT_MAX,
+	.owner		= THIS_MODULE,
+};
+
+static int __init nft_reject_inet_module_init(void)
+{
+	return nft_register_expr(&nft_reject_inet_type);
+}
+
+static void __exit nft_reject_inet_module_exit(void)
+{
+	nft_unregister_expr(&nft_reject_inet_type);
+}
+
+module_init(nft_reject_inet_module_init);
+module_exit(nft_reject_inet_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <[e-mail]>");
+MODULE_ALIAS_NFT_AF_EXPR(1, "reject");