2 * DCCP NAT protocol helper
4 * Copyright (c) 2005, 2006. 2008 Patrick McHardy <kaber@trash.net>
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
12 #include <linux/kernel.h>
13 #include <linux/module.h>
14 #include <linux/init.h>
15 #include <linux/skbuff.h>
17 #include <linux/dccp.h>
19 #include <net/netfilter/nf_conntrack.h>
20 #include <net/netfilter/nf_nat.h>
21 #include <net/netfilter/nf_nat_protocol.h>
23 static u_int16_t dccp_port_rover
;
26 dccp_unique_tuple(struct nf_conntrack_tuple
*tuple
,
27 const struct nf_nat_range
*range
,
28 enum nf_nat_manip_type maniptype
,
29 const struct nf_conn
*ct
)
31 nf_nat_proto_unique_tuple(tuple
, range
, maniptype
, ct
,
36 dccp_manip_pkt(struct sk_buff
*skb
,
37 unsigned int iphdroff
,
38 const struct nf_conntrack_tuple
*tuple
,
39 enum nf_nat_manip_type maniptype
)
41 const struct iphdr
*iph
= (const void *)(skb
->data
+ iphdroff
);
43 unsigned int hdroff
= iphdroff
+ iph
->ihl
* 4;
45 __be16
*portptr
, oldport
, newport
;
46 int hdrsize
= 8; /* DCCP connection tracking guarantees this much */
48 if (skb
->len
>= hdroff
+ sizeof(struct dccp_hdr
))
49 hdrsize
= sizeof(struct dccp_hdr
);
51 if (!skb_make_writable(skb
, hdroff
+ hdrsize
))
54 iph
= (struct iphdr
*)(skb
->data
+ iphdroff
);
55 hdr
= (struct dccp_hdr
*)(skb
->data
+ hdroff
);
57 if (maniptype
== IP_NAT_MANIP_SRC
) {
59 newip
= tuple
->src
.u3
.ip
;
60 newport
= tuple
->src
.u
.dccp
.port
;
61 portptr
= &hdr
->dccph_sport
;
64 newip
= tuple
->dst
.u3
.ip
;
65 newport
= tuple
->dst
.u
.dccp
.port
;
66 portptr
= &hdr
->dccph_dport
;
72 if (hdrsize
< sizeof(*hdr
))
75 inet_proto_csum_replace4(&hdr
->dccph_checksum
, skb
, oldip
, newip
, 1);
76 inet_proto_csum_replace2(&hdr
->dccph_checksum
, skb
, oldport
, newport
,
81 static const struct nf_nat_protocol nf_nat_protocol_dccp
= {
82 .protonum
= IPPROTO_DCCP
,
84 .manip_pkt
= dccp_manip_pkt
,
85 .in_range
= nf_nat_proto_in_range
,
86 .unique_tuple
= dccp_unique_tuple
,
87 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
88 .range_to_nlattr
= nf_nat_proto_range_to_nlattr
,
89 .nlattr_to_range
= nf_nat_proto_nlattr_to_range
,
93 static int __init
nf_nat_proto_dccp_init(void)
95 return nf_nat_protocol_register(&nf_nat_protocol_dccp
);
98 static void __exit
nf_nat_proto_dccp_fini(void)
100 nf_nat_protocol_unregister(&nf_nat_protocol_dccp
);
103 module_init(nf_nat_proto_dccp_init
);
104 module_exit(nf_nat_proto_dccp_fini
);
106 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
107 MODULE_DESCRIPTION("DCCP NAT protocol helper");
108 MODULE_LICENSE("GPL");