1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
3 * (C) 2008 Patrick McHardy <kaber@trash.net>
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
10 #include <linux/types.h>
11 #include <linux/init.h>
13 #include <linux/udp.h>
15 #include <linux/netfilter.h>
16 #include <linux/module.h>
17 #include <net/netfilter/nf_nat.h>
18 #include <net/netfilter/nf_nat_protocol.h>
20 static u_int16_t udplite_port_rover;
23 udplite_unique_tuple(struct nf_conntrack_tuple *tuple,
24 const struct nf_nat_ipv4_range *range,
25 enum nf_nat_manip_type maniptype,
26 const struct nf_conn *ct)
28 nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
33 udplite_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;
64 inet_proto_csum_replace4(&hdr->check, skb, oldip, newip, 1);
65 inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0);
67 hdr->check = CSUM_MANGLED_0;
73 static const struct nf_nat_protocol nf_nat_protocol_udplite = {
74 .protonum = IPPROTO_UDPLITE,
75 .manip_pkt = udplite_manip_pkt,
76 .in_range = nf_nat_proto_in_range,
77 .unique_tuple = udplite_unique_tuple,
78 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
79 .range_to_nlattr = nf_nat_proto_range_to_nlattr,
80 .nlattr_to_range = nf_nat_proto_nlattr_to_range,
84 static int __init nf_nat_proto_udplite_init(void)
86 return nf_nat_protocol_register(&nf_nat_protocol_udplite);
89 static void __exit nf_nat_proto_udplite_fini(void)
91 nf_nat_protocol_unregister(&nf_nat_protocol_udplite);
94 module_init(nf_nat_proto_udplite_init);
95 module_exit(nf_nat_proto_udplite_fini);
97 MODULE_LICENSE("GPL");
98 MODULE_DESCRIPTION("UDP-Lite NAT protocol helper");
99 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");