netfilter: nft_reject: split up reject module into IPv4 and IPv6 specifc parts

Currently the nft_reject module depends on symbols from ipv6. This is
wrong since no generic module should force IPv6 support to be loaded.
Split up the module into AF-specific and a generic part.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

3 files changed, 80 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 81c6910..a26ce03 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -61,6 +61,11 @@ config NFT_CHAIN_NAT_IPV4
 	  packet transformations such as the source, destination address and
 	  source and destination ports.
 
+config NFT_REJECT_IPV4
+	depends on NF_TABLES_IPV4
+	default NFT_REJECT
+	tristate
+
 config NF_TABLES_ARP
 	depends on NF_TABLES
 	tristate "ARP nf_tables support"
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index c16be9d..90b8240 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -30,6 +30,7 @@ obj-$(CONFIG_NF_NAT_PROTO_GRE) += nf_nat_proto_gre.o
 obj-$(CONFIG_NF_TABLES_IPV4) += nf_tables_ipv4.o
 obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV4) += nft_chain_route_ipv4.o
 obj-$(CONFIG_NFT_CHAIN_NAT_IPV4) += nft_chain_nat_ipv4.o
+obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_ipv4.o
 obj-$(CONFIG_NF_TABLES_ARP) += nf_tables_arp.o
 
 # generic IP tables 
diff --git a/net/ipv4/netfilter/nft_reject_ipv4.c b/net/ipv4/netfilter/nft_reject_ipv4.c
new file mode 100644
index 0000000..e935d8d
--- /dev/null
+++ b/net/ipv4/netfilter/nft_reject_ipv4.c
@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2008-2009 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2013 Eric Leblond <eric@regit.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
+ * published by the Free Software Foundation.
+ *
+ * Development of this code funded by Astaro AG (http://www.astaro.com/)
+ */
+
+#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/icmp.h>
+#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)
+{
+	struct nft_reject *priv = nft_expr_priv(expr);
+
+	switch (priv->type) {
+	case NFT_REJECT_ICMP_UNREACH:
+		nf_send_unreach(pkt->skb, priv->icmp_code);
+		break;
+	case NFT_REJECT_TCP_RST:
+		nf_send_reset(pkt->skb, pkt->ops->hooknum);
+		break;
+	}
+
+	data[NFT_REG_VERDICT].verdict = NF_DROP;
+}
+
+static struct nft_expr_type nft_reject_ipv4_type;
+static const struct nft_expr_ops nft_reject_ipv4_ops = {
+	.type		= &nft_reject_ipv4_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_reject)),
+	.eval		= nft_reject_ipv4_eval,
+	.init		= nft_reject_init,
+	.dump		= nft_reject_dump,
+};
+
+static struct nft_expr_type nft_reject_ipv4_type __read_mostly = {
+	.family		= NFPROTO_IPV4,
+	.name		= "reject",
+	.ops		= &nft_reject_ipv4_ops,
+	.policy		= nft_reject_policy,
+	.maxattr	= NFTA_REJECT_MAX,
+	.owner		= THIS_MODULE,
+};
+
+static int __init nft_reject_ipv4_module_init(void)
+{
+	return nft_register_expr(&nft_reject_ipv4_type);
+}
+
+static void __exit nft_reject_ipv4_module_exit(void)
+{
+	nft_unregister_expr(&nft_reject_ipv4_type);
+}
+
+module_init(nft_reject_ipv4_module_init);
+module_exit(nft_reject_ipv4_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_ALIAS_NFT_AF_EXPR(AF_INET, "reject");