1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
9 #include <linux/types.h>
10 #include <linux/export.h>
11 #include <linux/init.h>
12 #include <linux/udp.h>
14 #include <linux/netfilter.h>
15 #include <net/netfilter/nf_nat.h>
16 #include <net/netfilter/nf_nat_core.h>
17 #include <net/netfilter/nf_nat_l3proto.h>
18 #include <net/netfilter/nf_nat_l4proto.h>
20 static u16 udp_port_rover
;
23 udp_unique_tuple(const struct nf_nat_l3proto
*l3proto
,
24 struct nf_conntrack_tuple
*tuple
,
25 const struct nf_nat_range
*range
,
26 enum nf_nat_manip_type maniptype
,
27 const struct nf_conn
*ct
)
29 nf_nat_l4proto_unique_tuple(l3proto
, tuple
, range
, maniptype
, ct
,
34 udp_manip_pkt(struct sk_buff
*skb
,
35 const struct nf_nat_l3proto
*l3proto
,
36 unsigned int iphdroff
, unsigned int hdroff
,
37 const struct nf_conntrack_tuple
*tuple
,
38 enum nf_nat_manip_type maniptype
)
41 __be16
*portptr
, newport
;
43 if (!skb_make_writable(skb
, hdroff
+ sizeof(*hdr
)))
45 hdr
= (struct udphdr
*)(skb
->data
+ hdroff
);
47 if (maniptype
== NF_NAT_MANIP_SRC
) {
48 /* Get rid of src port */
49 newport
= tuple
->src
.u
.udp
.port
;
50 portptr
= &hdr
->source
;
52 /* Get rid of dst port */
53 newport
= tuple
->dst
.u
.udp
.port
;
56 if (hdr
->check
|| skb
->ip_summed
== CHECKSUM_PARTIAL
) {
57 l3proto
->csum_update(skb
, iphdroff
, &hdr
->check
,
59 inet_proto_csum_replace2(&hdr
->check
, skb
, *portptr
, newport
,
62 hdr
->check
= CSUM_MANGLED_0
;
68 const struct nf_nat_l4proto nf_nat_l4proto_udp
= {
69 .l4proto
= IPPROTO_UDP
,
70 .manip_pkt
= udp_manip_pkt
,
71 .in_range
= nf_nat_l4proto_in_range
,
72 .unique_tuple
= udp_unique_tuple
,
73 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
74 .nlattr_to_range
= nf_nat_l4proto_nlattr_to_range
,