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>
13 #include <linux/udp.h>
15 #include <linux/netfilter.h>
16 #include <net/netfilter/nf_nat.h>
17 #include <net/netfilter/nf_nat_core.h>
18 #include <net/netfilter/nf_nat_rule.h>
19 #include <net/netfilter/nf_nat_protocol.h>
21 static u_int16_t udp_port_rover
;
24 udp_unique_tuple(struct nf_conntrack_tuple
*tuple
,
25 const struct nf_nat_ipv4_range
*range
,
26 enum nf_nat_manip_type maniptype
,
27 const struct nf_conn
*ct
)
29 nf_nat_proto_unique_tuple(tuple
, range
, maniptype
, ct
, &udp_port_rover
);
33 udp_manip_pkt(struct sk_buff
*skb
,
34 unsigned int iphdroff
,
35 const struct nf_conntrack_tuple
*tuple
,
36 enum nf_nat_manip_type maniptype
)
38 const struct iphdr
*iph
= (struct iphdr
*)(skb
->data
+ iphdroff
);
40 unsigned int hdroff
= iphdroff
+ iph
->ihl
*4;
42 __be16
*portptr
, newport
;
44 if (!skb_make_writable(skb
, hdroff
+ sizeof(*hdr
)))
47 iph
= (struct iphdr
*)(skb
->data
+ iphdroff
);
48 hdr
= (struct udphdr
*)(skb
->data
+ hdroff
);
50 if (maniptype
== NF_NAT_MANIP_SRC
) {
51 /* Get rid of src ip and src pt */
53 newip
= tuple
->src
.u3
.ip
;
54 newport
= tuple
->src
.u
.udp
.port
;
55 portptr
= &hdr
->source
;
57 /* Get rid of dst ip and dst pt */
59 newip
= tuple
->dst
.u3
.ip
;
60 newport
= tuple
->dst
.u
.udp
.port
;
63 if (hdr
->check
|| skb
->ip_summed
== CHECKSUM_PARTIAL
) {
64 inet_proto_csum_replace4(&hdr
->check
, skb
, oldip
, newip
, 1);
65 inet_proto_csum_replace2(&hdr
->check
, skb
, *portptr
, newport
,
68 hdr
->check
= CSUM_MANGLED_0
;
74 const struct nf_nat_protocol nf_nat_protocol_udp
= {
75 .protonum
= IPPROTO_UDP
,
76 .manip_pkt
= udp_manip_pkt
,
77 .in_range
= nf_nat_proto_in_range
,
78 .unique_tuple
= udp_unique_tuple
,
79 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
80 .nlattr_to_range
= nf_nat_proto_nlattr_to_range
,