netfilter: nf_tables: add ARP filtering support

This patch registers the ARP family and he filter chain type
for this family.

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

4 files changed, 108 insertions, 0 deletions

diff --git a/include/net/netns/nftables.h b/include/net/netns/nftables.h
index 08a4248a12b5..15d056d534e3 100644
--- a/include/net/netns/nftables.h
+++ b/include/net/netns/nftables.h
@@ -10,6 +10,7 @@ struct netns_nftables {
         struct list_head        commit_list;
         struct nft_af_info      *ipv4;
         struct nft_af_info      *ipv6;
+        struct nft_af_info      *arp;
         struct nft_af_info      *bridge;
         u8                      gencursor;
         u8                      genctr;
diff --git a/net/ipv4/netfilter/Kconfig b/net/ipv4/netfilter/Kconfig
index 1f37ef67f1ac..40d56073cd19 100644
--- a/net/ipv4/netfilter/Kconfig
+++ b/net/ipv4/netfilter/Kconfig
@@ -53,6 +53,10 @@ config NFT_CHAIN_NAT_IPV4
         depends on NF_NAT_IPV4 && NFT_NAT
         tristate "IPv4 nf_tables nat chain support"
 
+config NF_TABLES_ARP
+        depends on NF_TABLES
+        tristate "ARP nf_tables support"
+
 config IP_NF_IPTABLES
         tristate "IP tables support (required for filtering/masq/NAT)"
         default m if NETFILTER_ADVANCED=n
diff --git a/net/ipv4/netfilter/Makefile b/net/ipv4/netfilter/Makefile
index 91e0bd71a6d3..19df72b7ba88 100644
--- a/net/ipv4/netfilter/Makefile
+++ b/net/ipv4/netfilter/Makefile
@@ -31,6 +31,7 @@ obj-$(CONFIG_NF_TABLES_IPV4) += nf_tables_ipv4.o
 obj-$(CONFIG_NFT_REJECT_IPV4) += nft_reject_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_NF_TABLES_ARP) += nf_tables_arp.o
 
 # generic IP tables 
 obj-$(CONFIG_IP_NF_IPTABLES) += ip_tables.o
diff --git a/net/ipv4/netfilter/nf_tables_arp.c b/net/ipv4/netfilter/nf_tables_arp.c
new file mode 100644
index 000000000000..3e67ef1c676f
--- /dev/null
+++ b/net/ipv4/netfilter/nf_tables_arp.c
@@ -0,0 +1,102 @@
+/*
+ * Copyright (c) 2008-2010 Patrick McHardy <kaber@trash.net>
+ * Copyright (c) 2013 Pablo Neira Ayuso <pablo@netfilter.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/module.h>
+#include <linux/init.h>
+#include <linux/netfilter_arp.h>
+#include <net/netfilter/nf_tables.h>
+
+static struct nft_af_info nft_af_arp __read_mostly = {
+        .family         = NFPROTO_ARP,
+        .nhooks         = NF_ARP_NUMHOOKS,
+        .owner          = THIS_MODULE,
+};
+
+static int nf_tables_arp_init_net(struct net *net)
+{
+        net->nft.arp = kmalloc(sizeof(struct nft_af_info), GFP_KERNEL);
+        if (net->nft.arp== NULL)
+                return -ENOMEM;
+
+        memcpy(net->nft.arp, &nft_af_arp, sizeof(nft_af_arp));
+
+        if (nft_register_afinfo(net, net->nft.arp) < 0)
+                goto err;
+
+        return 0;
+err:
+        kfree(net->nft.arp);
+        return -ENOMEM;
+}
+
+static void nf_tables_arp_exit_net(struct net *net)
+{
+        nft_unregister_afinfo(net->nft.arp);
+        kfree(net->nft.arp);
+}
+
+static struct pernet_operations nf_tables_arp_net_ops = {
+        .init   = nf_tables_arp_init_net,
+        .exit   = nf_tables_arp_exit_net,
+};
+
+static unsigned int
+nft_do_chain_arp(const struct nf_hook_ops *ops,
+                  struct sk_buff *skb,
+                  const struct net_device *in,
+                  const struct net_device *out,
+                  int (*okfn)(struct sk_buff *))
+{
+        struct nft_pktinfo pkt;
+
+        nft_set_pktinfo(&pkt, ops, skb, in, out);
+
+        return nft_do_chain_pktinfo(&pkt, ops);
+}
+
+static struct nf_chain_type filter_arp = {
+        .family         = NFPROTO_ARP,
+        .name           = "filter",
+        .type           = NFT_CHAIN_T_DEFAULT,
+        .hook_mask      = (1 << NF_ARP_IN) |
+                          (1 << NF_ARP_OUT) |
+                          (1 << NF_ARP_FORWARD),
+        .fn             = {
+                [NF_ARP_IN]             = nft_do_chain_arp,
+                [NF_ARP_OUT]            = nft_do_chain_arp,
+                [NF_ARP_FORWARD]        = nft_do_chain_arp,
+        },
+};
+
+static int __init nf_tables_arp_init(void)
+{
+        int ret;
+
+        nft_register_chain_type(&filter_arp);
+        ret = register_pernet_subsys(&nf_tables_arp_net_ops);
+        if (ret < 0)
+                nft_unregister_chain_type(&filter_arp);
+
+        return ret;
+}
+
+static void __exit nf_tables_arp_exit(void)
+{
+        unregister_pernet_subsys(&nf_tables_arp_net_ops);
+        nft_unregister_chain_type(&filter_arp);
+}
+
+module_init(nf_tables_arp_init);
+module_exit(nf_tables_arp_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
+MODULE_ALIAS_NFT_FAMILY(3); /* NFPROTO_ARP */