1 files changed, 110 insertions, 0 deletions
diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c
new file mode 100644
index 000000000..b9062f455
--- /dev/null
+++ b/net/ipv4/netfilter/iptable_filter.c
@@ -0,0 +1,110 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This is the 1999 rewrite of IP Firewalling, aiming for kernel 2.3.x.
+ *
+ * Copyright (C) 1999 Paul `Rusty' Russell & Michael J. Neuling
+ * Copyright (C) 2000-2004 Netfilter Core Team <coreteam@netfilter.org>
+ */
+
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/slab.h>
+#include <net/ip.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("iptables filter table");
+
+#define FILTER_VALID_HOOKS ((1 << NF_INET_LOCAL_IN) | \
+			    (1 << NF_INET_FORWARD) | \
+			    (1 << NF_INET_LOCAL_OUT))
+
+static const struct xt_table packet_filter = {
+	.name		= "filter",
+	.valid_hooks	= FILTER_VALID_HOOKS,
+	.me		= THIS_MODULE,
+	.af		= NFPROTO_IPV4,
+	.priority	= NF_IP_PRI_FILTER,
+};
+
+static struct nf_hook_ops *filter_ops __read_mostly;
+
+/* Default to forward because I got too much mail already. */
+static bool forward __read_mostly = true;
+module_param(forward, bool, 0000);
+
+static int iptable_filter_table_init(struct net *net)
+{
+	struct ipt_replace *repl;
+	int err;
+
+	repl = ipt_alloc_initial_table(&packet_filter);
+	if (repl == NULL)
+		return -ENOMEM;
+	/* Entry 1 is the FORWARD hook */
+	((struct ipt_standard *)repl->entries)[1].target.verdict =
+		forward ? -NF_ACCEPT - 1 : -NF_DROP - 1;
+
+	err = ipt_register_table(net, &packet_filter, repl, filter_ops);
+	kfree(repl);
+	return err;
+}
+
+static int __net_init iptable_filter_net_init(struct net *net)
+{
+	if (!forward)
+		return iptable_filter_table_init(net);
+
+	return 0;
+}
+
+static void __net_exit iptable_filter_net_pre_exit(struct net *net)
+{
+	ipt_unregister_table_pre_exit(net, "filter");
+}
+
+static void __net_exit iptable_filter_net_exit(struct net *net)
+{
+	ipt_unregister_table_exit(net, "filter");
+}
+
+static struct pernet_operations iptable_filter_net_ops = {
+	.init = iptable_filter_net_init,
+	.pre_exit = iptable_filter_net_pre_exit,
+	.exit = iptable_filter_net_exit,
+};
+
+static int __init iptable_filter_init(void)
+{
+	int ret = xt_register_template(&packet_filter,
+				       iptable_filter_table_init);
+
+	if (ret < 0)
+		return ret;
+
+	filter_ops = xt_hook_ops_alloc(&packet_filter, ipt_do_table);
+	if (IS_ERR(filter_ops)) {
+		xt_unregister_template(&packet_filter);
+		return PTR_ERR(filter_ops);
+	}
+
+	ret = register_pernet_subsys(&iptable_filter_net_ops);
+	if (ret < 0) {
+		xt_unregister_template(&packet_filter);
+		kfree(filter_ops);
+		return ret;
+	}
+
+	return 0;
+}
+
+static void __exit iptable_filter_fini(void)
+{
+	unregister_pernet_subsys(&iptable_filter_net_ops);
+	xt_unregister_template(&packet_filter);
+	kfree(filter_ops);
+}
+
+module_init(iptable_filter_init);
+module_exit(iptable_filter_fini);