From 57f0f512b273f60d52568b8c6b77e17f5636edc0 Mon Sep 17 00:00:00 2001
From: André Fabian Silva Delgado <emulatorman@parabola.nu>
Date: Wed, 5 Aug 2015 17:04:01 -0300
Subject: Initial import

---
 net/ipv4/netfilter/iptable_filter.c | 109 ++++++++++++++++++++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 net/ipv4/netfilter/iptable_filter.c

(limited to 'net/ipv4/netfilter/iptable_filter.c')

diff --git a/net/ipv4/netfilter/iptable_filter.c b/net/ipv4/netfilter/iptable_filter.c
new file mode 100644
index 000000000..a0f3beca5
--- /dev/null
+++ b/net/ipv4/netfilter/iptable_filter.c
@@ -0,0 +1,109 @@
+/*
+ * 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>
+ *
+ * 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/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 unsigned int
+iptable_filter_hook(const struct nf_hook_ops *ops, struct sk_buff *skb,
+		    const struct nf_hook_state *state)
+{
+	const struct net *net;
+
+	if (ops->hooknum == NF_INET_LOCAL_OUT &&
+	    (skb->len < sizeof(struct iphdr) ||
+	     ip_hdrlen(skb) < sizeof(struct iphdr)))
+		/* root is playing with raw sockets. */
+		return NF_ACCEPT;
+
+	net = dev_net(state->in ? state->in : state->out);
+	return ipt_do_table(skb, ops->hooknum, state, net->ipv4.iptable_filter);
+}
+
+static struct nf_hook_ops *filter_ops __read_mostly;
+
+/* Default to forward because I got too much mail already. */
+static bool forward = true;
+module_param(forward, bool, 0000);
+
+static int __net_init iptable_filter_net_init(struct net *net)
+{
+	struct ipt_replace *repl;
+
+	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;
+
+	net->ipv4.iptable_filter =
+		ipt_register_table(net, &packet_filter, repl);
+	kfree(repl);
+	return PTR_ERR_OR_ZERO(net->ipv4.iptable_filter);
+}
+
+static void __net_exit iptable_filter_net_exit(struct net *net)
+{
+	ipt_unregister_table(net, net->ipv4.iptable_filter);
+}
+
+static struct pernet_operations iptable_filter_net_ops = {
+	.init = iptable_filter_net_init,
+	.exit = iptable_filter_net_exit,
+};
+
+static int __init iptable_filter_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&iptable_filter_net_ops);
+	if (ret < 0)
+		return ret;
+
+	/* Register hooks */
+	filter_ops = xt_hook_link(&packet_filter, iptable_filter_hook);
+	if (IS_ERR(filter_ops)) {
+		ret = PTR_ERR(filter_ops);
+		unregister_pernet_subsys(&iptable_filter_net_ops);
+	}
+
+	return ret;
+}
+
+static void __exit iptable_filter_fini(void)
+{
+	xt_hook_unlink(&packet_filter, filter_ops);
+	unregister_pernet_subsys(&iptable_filter_net_ops);
+}
+
+module_init(iptable_filter_init);
+module_exit(iptable_filter_fini);
-- 
cgit v1.2.3-54-g00ecf