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/*
* nf_nat_proto_gre.c
*
* NAT protocol helper module for GRE.
*
* GRE is a generic encapsulation protocol, which is generally not very
* suited for NAT, as it has no protocol-specific part as port numbers.
*
* It has an optional key field, which may help us distinguishing two
* connections between the same two hosts.
*
* GRE is defined in RFC 1701 and RFC 1702, as well as RFC 2784
*
* PPTP is built on top of a modified version of GRE, and has a mandatory
* field called "CallID", which serves us for the same purpose as the key
* field in plain GRE.
*
* Documentation about PPTP can be found in RFC 2637
*
* (C) 2000-2005 by Harald Welte <laforge@gnumonks.org>
*
* Development of this code funded by Astaro AG (http://www.astaro.com/)
*
* (C) 2006-2012 Patrick McHardy <kaber@trash.net>
*
*/
#include <linux/module.h>
#include <linux/skbuff.h>
#include <linux/ip.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_l4proto.h>
#include <linux/netfilter/nf_conntrack_proto_gre.h>
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Harald Welte <laforge@gnumonks.org>");
MODULE_DESCRIPTION("Netfilter NAT protocol helper module for GRE");
static const struct nf_nat_l4proto gre = {
.l4proto = IPPROTO_GRE,
};
static int __init nf_nat_proto_gre_init(void)
{
return nf_nat_l4proto_register(NFPROTO_IPV4, &gre);
}
static void __exit nf_nat_proto_gre_fini(void)
{
nf_nat_l4proto_unregister(NFPROTO_IPV4, &gre);
}
module_init(nf_nat_proto_gre_init);
module_exit(nf_nat_proto_gre_fini);
void nf_nat_need_gre(void)
{
return;
}
EXPORT_SYMBOL_GPL(nf_nat_need_gre);
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