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/udp.h>
13
14 #include <linux/netfilter.h>
15 #include <linux/module.h>
16 #include <net/netfilter/nf_nat.h>
17 #include <net/netfilter/nf_nat_l3proto.h>
18 #include <net/netfilter/nf_nat_l4proto.h>
19
20 static u16 udplite_port_rover;
21
22 static void
udplite_unique_tuple(const struct nf_nat_l3proto * l3proto,struct nf_conntrack_tuple * tuple,const struct nf_nat_range * range,enum nf_nat_manip_type maniptype,const struct nf_conn * ct)23 udplite_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)
28 {
29 nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
30 &udplite_port_rover);
31 }
32
33 static bool
udplite_manip_pkt(struct sk_buff * skb,const struct nf_nat_l3proto * l3proto,unsigned int iphdroff,unsigned int hdroff,const struct nf_conntrack_tuple * tuple,enum nf_nat_manip_type maniptype)34 udplite_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)
39 {
40 struct udphdr *hdr;
41 __be16 *portptr, newport;
42
43 if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
44 return false;
45
46 hdr = (struct udphdr *)(skb->data + hdroff);
47
48 if (maniptype == NF_NAT_MANIP_SRC) {
49 /* Get rid of source port */
50 newport = tuple->src.u.udp.port;
51 portptr = &hdr->source;
52 } else {
53 /* Get rid of dst port */
54 newport = tuple->dst.u.udp.port;
55 portptr = &hdr->dest;
56 }
57
58 l3proto->csum_update(skb, iphdroff, &hdr->check, tuple, maniptype);
59 inet_proto_csum_replace2(&hdr->check, skb, *portptr, newport, false);
60 if (!hdr->check)
61 hdr->check = CSUM_MANGLED_0;
62
63 *portptr = newport;
64 return true;
65 }
66
67 static const struct nf_nat_l4proto nf_nat_l4proto_udplite = {
68 .l4proto = IPPROTO_UDPLITE,
69 .manip_pkt = udplite_manip_pkt,
70 .in_range = nf_nat_l4proto_in_range,
71 .unique_tuple = udplite_unique_tuple,
72 #if IS_ENABLED(CONFIG_NF_CT_NETLINK)
73 .nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
74 #endif
75 };
76
nf_nat_proto_udplite_init(void)77 static int __init nf_nat_proto_udplite_init(void)
78 {
79 int err;
80
81 err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
82 if (err < 0)
83 goto err1;
84 err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_udplite);
85 if (err < 0)
86 goto err2;
87 return 0;
88
89 err2:
90 nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
91 err1:
92 return err;
93 }
94
nf_nat_proto_udplite_fini(void)95 static void __exit nf_nat_proto_udplite_fini(void)
96 {
97 nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_udplite);
98 nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_udplite);
99 }
100
101 module_init(nf_nat_proto_udplite_init);
102 module_exit(nf_nat_proto_udplite_fini);
103
104 MODULE_LICENSE("GPL");
105 MODULE_DESCRIPTION("UDP-Lite NAT protocol helper");
106 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
107