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 81c6910cfa92..a26ce035e3fa 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 c16be9d58420..90b82405331e 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 000000000000..e935d8de1182
--- /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");