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/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
* (C) 2008 Patrick McHardy <kaber@trash.net>
*
* 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/types.h>
#include <linux/init.h>
#include <linux/ip.h>
#include <linux/udp.h>
#include <linux/netfilter.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_protocol.h>
static u_int16_t udplite_port_rover;
static void
udplite_unique_tuple(struct nf_conntrack_tuple *tuple,
const struct nf_nat_range *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
&udplite_port_rover);
}
static bool
udplite_manip_pkt(struct sk_buff *skb,
unsigned int iphdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
{
const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
struct udphdr *hdr;
unsigned int hdroff = iphdroff + iph->ihl*4;
__be32 oldip, newip;
__be16 *portptr, newport;
if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
return false;
iph = (struct iphdr *)(skb->data + iphdroff);
hdr = (struct udphdr *)(skb->data + hdroff);
if (maniptype == IP_NAT_MANIP_SRC) {
/* Get rid of src ip and src pt */
oldip = iph->saddr;
newip = tuple->src.u3.ip;
newport = tuple->src.u.udp.port;
portptr = &hdr->source;
} else {
/* Get rid of dst ip and dst pt */
oldip = iph->daddr;
newip = tuple->dst.u3.ip;
newport = tuple->dst.u.udp.port;
portptr = &hdr->dest;
}
inet_proto_csum_replace4(&hdr->check, skb, oldip, newip, 1);
inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0);
if (!hdr->check)
hdr->check = CSUM_MANGLED_0;
*portptr = newport;
return true;
}
static const struct nf_nat_protocol nf_nat_protocol_udplite = {
.protonum = IPPROTO_UDPLITE,
.me = THIS_MODULE,
.manip_pkt = udplite_manip_pkt,
.in_range = nf_nat_proto_in_range,
.unique_tuple = udplite_unique_tuple,
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
.range_to_nlattr = nf_nat_proto_range_to_nlattr,
.nlattr_to_range = nf_nat_proto_nlattr_to_range,
#endif
};
static int __init nf_nat_proto_udplite_init(void)
{
return nf_nat_protocol_register(&nf_nat_protocol_udplite);
}
static void __exit nf_nat_proto_udplite_fini(void)
{
nf_nat_protocol_unregister(&nf_nat_protocol_udplite);
}
module_init(nf_nat_proto_udplite_init);
module_exit(nf_nat_proto_udplite_fini);
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("UDP-Lite NAT protocol helper");
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
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