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6185f870 PM |
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> | |
4 | * | |
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. | |
8 | */ | |
9 | ||
10 | #include <linux/types.h> | |
11 | #include <linux/init.h> | |
12 | #include <linux/ip.h> | |
13 | #include <linux/udp.h> | |
14 | ||
15 | #include <linux/netfilter.h> | |
3a9a231d | 16 | #include <linux/module.h> |
6185f870 PM |
17 | #include <net/netfilter/nf_nat.h> |
18 | #include <net/netfilter/nf_nat_protocol.h> | |
19 | ||
20 | static u_int16_t udplite_port_rover; | |
21 | ||
f43dc98b | 22 | static void |
6185f870 | 23 | udplite_unique_tuple(struct nf_conntrack_tuple *tuple, |
cbc9f2f4 | 24 | const struct nf_nat_ipv4_range *range, |
6185f870 PM |
25 | enum nf_nat_manip_type maniptype, |
26 | const struct nf_conn *ct) | |
27 | { | |
f43dc98b CG |
28 | nf_nat_proto_unique_tuple(tuple, range, maniptype, ct, |
29 | &udplite_port_rover); | |
6185f870 PM |
30 | } |
31 | ||
f2ea825f | 32 | static bool |
6185f870 PM |
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) | |
37 | { | |
38 | const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff); | |
39 | struct udphdr *hdr; | |
40 | unsigned int hdroff = iphdroff + iph->ihl*4; | |
41 | __be32 oldip, newip; | |
42 | __be16 *portptr, newport; | |
43 | ||
44 | if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) | |
f2ea825f | 45 | return false; |
6185f870 PM |
46 | |
47 | iph = (struct iphdr *)(skb->data + iphdroff); | |
48 | hdr = (struct udphdr *)(skb->data + hdroff); | |
49 | ||
cbc9f2f4 | 50 | if (maniptype == NF_NAT_MANIP_SRC) { |
6185f870 PM |
51 | /* Get rid of src ip and src pt */ |
52 | oldip = iph->saddr; | |
53 | newip = tuple->src.u3.ip; | |
54 | newport = tuple->src.u.udp.port; | |
55 | portptr = &hdr->source; | |
56 | } else { | |
57 | /* Get rid of dst ip and dst pt */ | |
58 | oldip = iph->daddr; | |
59 | newip = tuple->dst.u3.ip; | |
60 | newport = tuple->dst.u.udp.port; | |
61 | portptr = &hdr->dest; | |
62 | } | |
63 | ||
64 | inet_proto_csum_replace4(&hdr->check, skb, oldip, newip, 1); | |
65 | inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, 0); | |
66 | if (!hdr->check) | |
67 | hdr->check = CSUM_MANGLED_0; | |
68 | ||
69 | *portptr = newport; | |
f2ea825f | 70 | return true; |
6185f870 PM |
71 | } |
72 | ||
73 | static const struct nf_nat_protocol nf_nat_protocol_udplite = { | |
74 | .protonum = IPPROTO_UDPLITE, | |
6185f870 PM |
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) | |
6185f870 PM |
79 | .nlattr_to_range = nf_nat_proto_nlattr_to_range, |
80 | #endif | |
81 | }; | |
82 | ||
83 | static int __init nf_nat_proto_udplite_init(void) | |
84 | { | |
85 | return nf_nat_protocol_register(&nf_nat_protocol_udplite); | |
86 | } | |
87 | ||
88 | static void __exit nf_nat_proto_udplite_fini(void) | |
89 | { | |
90 | nf_nat_protocol_unregister(&nf_nat_protocol_udplite); | |
91 | } | |
92 | ||
93 | module_init(nf_nat_proto_udplite_init); | |
94 | module_exit(nf_nat_proto_udplite_fini); | |
95 | ||
96 | MODULE_LICENSE("GPL"); | |
97 | MODULE_DESCRIPTION("UDP-Lite NAT protocol helper"); | |
98 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |