Initial import

1 files changed, 147 insertions, 0 deletions

diff --git a/net/ipv4/netfilter/iptable_mangle.c b/net/ipv4/netfilter/iptable_mangle.c
new file mode 100644
index 000000000..62cbb8c5f
--- /dev/null
+++ b/net/ipv4/netfilter/iptable_mangle.c
@@ -0,0 +1,147 @@
+/*
+ * 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/netfilter_ipv4/ip_tables.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/slab.h>
+#include <net/sock.h>
+#include <net/route.h>
+#include <linux/ip.h>
+#include <net/ip.h>
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
+MODULE_DESCRIPTION("iptables mangle table");
+
+#define MANGLE_VALID_HOOKS ((1 << NF_INET_PRE_ROUTING) | \
+			    (1 << NF_INET_LOCAL_IN) | \
+			    (1 << NF_INET_FORWARD) | \
+			    (1 << NF_INET_LOCAL_OUT) | \
+			    (1 << NF_INET_POST_ROUTING))
+
+static const struct xt_table packet_mangler = {
+	.name		= "mangle",
+	.valid_hooks	= MANGLE_VALID_HOOKS,
+	.me		= THIS_MODULE,
+	.af		= NFPROTO_IPV4,
+	.priority	= NF_IP_PRI_MANGLE,
+};
+
+static unsigned int
+ipt_mangle_out(struct sk_buff *skb, const struct nf_hook_state *state)
+{
+	struct net_device *out = state->out;
+	unsigned int ret;
+	const struct iphdr *iph;
+	u_int8_t tos;
+	__be32 saddr, daddr;
+	u_int32_t mark;
+	int err;
+
+	/* root is playing with raw sockets. */
+	if (skb->len < sizeof(struct iphdr) ||
+	    ip_hdrlen(skb) < sizeof(struct iphdr))
+		return NF_ACCEPT;
+
+	/* Save things which could affect route */
+	mark = skb->mark;
+	iph = ip_hdr(skb);
+	saddr = iph->saddr;
+	daddr = iph->daddr;
+	tos = iph->tos;
+
+	ret = ipt_do_table(skb, NF_INET_LOCAL_OUT, state,
+			   dev_net(out)->ipv4.iptable_mangle);
+	/* Reroute for ANY change. */
+	if (ret != NF_DROP && ret != NF_STOLEN) {
+		iph = ip_hdr(skb);
+
+		if (iph->saddr != saddr ||
+		    iph->daddr != daddr ||
+		    skb->mark != mark ||
+		    iph->tos != tos) {
+			err = ip_route_me_harder(skb, RTN_UNSPEC);
+			if (err < 0)
+				ret = NF_DROP_ERR(err);
+		}
+	}
+
+	return ret;
+}
+
+/* The work comes in here from netfilter.c. */
+static unsigned int
+iptable_mangle_hook(const struct nf_hook_ops *ops,
+		     struct sk_buff *skb,
+		     const struct nf_hook_state *state)
+{
+	if (ops->hooknum == NF_INET_LOCAL_OUT)
+		return ipt_mangle_out(skb, state);
+	if (ops->hooknum == NF_INET_POST_ROUTING)
+		return ipt_do_table(skb, ops->hooknum, state,
+				    dev_net(state->out)->ipv4.iptable_mangle);
+	/* PREROUTING/INPUT/FORWARD: */
+	return ipt_do_table(skb, ops->hooknum, state,
+			    dev_net(state->in)->ipv4.iptable_mangle);
+}
+
+static struct nf_hook_ops *mangle_ops __read_mostly;
+
+static int __net_init iptable_mangle_net_init(struct net *net)
+{
+	struct ipt_replace *repl;
+
+	repl = ipt_alloc_initial_table(&packet_mangler);
+	if (repl == NULL)
+		return -ENOMEM;
+	net->ipv4.iptable_mangle =
+		ipt_register_table(net, &packet_mangler, repl);
+	kfree(repl);
+	return PTR_ERR_OR_ZERO(net->ipv4.iptable_mangle);
+}
+
+static void __net_exit iptable_mangle_net_exit(struct net *net)
+{
+	ipt_unregister_table(net, net->ipv4.iptable_mangle);
+}
+
+static struct pernet_operations iptable_mangle_net_ops = {
+	.init = iptable_mangle_net_init,
+	.exit = iptable_mangle_net_exit,
+};
+
+static int __init iptable_mangle_init(void)
+{
+	int ret;
+
+	ret = register_pernet_subsys(&iptable_mangle_net_ops);
+	if (ret < 0)
+		return ret;
+
+	/* Register hooks */
+	mangle_ops = xt_hook_link(&packet_mangler, iptable_mangle_hook);
+	if (IS_ERR(mangle_ops)) {
+		ret = PTR_ERR(mangle_ops);
+		unregister_pernet_subsys(&iptable_mangle_net_ops);
+	}
+
+	return ret;
+}
+
+static void __exit iptable_mangle_fini(void)
+{
+	xt_hook_unlink(&packet_mangler, mangle_ops);
+	unregister_pernet_subsys(&iptable_mangle_net_ops);
+}
+
+module_init(iptable_mangle_init);
+module_exit(iptable_mangle_fini);