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9d908a69 PM |
1 | /* |
2 | * Copyright (c) 2008 Patrick McHardy <kaber@trash.net> | |
3 | * | |
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. | |
7 | */ | |
8 | ||
9 | #include <linux/types.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/ip.h> | |
12 | #include <linux/sctp.h> | |
13 | #include <net/sctp/checksum.h> | |
14 | ||
15 | #include <net/netfilter/nf_nat_protocol.h> | |
16 | ||
17 | static u_int16_t nf_sctp_port_rover; | |
18 | ||
f2ea825f | 19 | static bool |
9d908a69 PM |
20 | sctp_unique_tuple(struct nf_conntrack_tuple *tuple, |
21 | const struct nf_nat_range *range, | |
22 | enum nf_nat_manip_type maniptype, | |
23 | const struct nf_conn *ct) | |
24 | { | |
25 | return nf_nat_proto_unique_tuple(tuple, range, maniptype, ct, | |
26 | &nf_sctp_port_rover); | |
27 | } | |
28 | ||
f2ea825f | 29 | static bool |
9d908a69 PM |
30 | sctp_manip_pkt(struct sk_buff *skb, |
31 | unsigned int iphdroff, | |
32 | const struct nf_conntrack_tuple *tuple, | |
33 | enum nf_nat_manip_type maniptype) | |
34 | { | |
35 | const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff); | |
343a9972 | 36 | struct sk_buff *frag; |
9d908a69 PM |
37 | sctp_sctphdr_t *hdr; |
38 | unsigned int hdroff = iphdroff + iph->ihl*4; | |
39 | __be32 oldip, newip; | |
336d3262 | 40 | __be32 crc32; |
9d908a69 PM |
41 | |
42 | if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) | |
f2ea825f | 43 | return false; |
9d908a69 PM |
44 | |
45 | iph = (struct iphdr *)(skb->data + iphdroff); | |
46 | hdr = (struct sctphdr *)(skb->data + hdroff); | |
47 | ||
48 | if (maniptype == IP_NAT_MANIP_SRC) { | |
49 | /* Get rid of src ip and src pt */ | |
50 | oldip = iph->saddr; | |
51 | newip = tuple->src.u3.ip; | |
52 | hdr->source = tuple->src.u.sctp.port; | |
53 | } else { | |
54 | /* Get rid of dst ip and dst pt */ | |
55 | oldip = iph->daddr; | |
56 | newip = tuple->dst.u3.ip; | |
57 | hdr->dest = tuple->dst.u.sctp.port; | |
58 | } | |
59 | ||
60 | crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff); | |
0808dc80 | 61 | skb_walk_frags(skb, frag) |
343a9972 | 62 | crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag), |
9d908a69 PM |
63 | crc32); |
64 | crc32 = sctp_end_cksum(crc32); | |
336d3262 | 65 | hdr->checksum = crc32; |
9d908a69 | 66 | |
f2ea825f | 67 | return true; |
9d908a69 PM |
68 | } |
69 | ||
70 | static const struct nf_nat_protocol nf_nat_protocol_sctp = { | |
71 | .protonum = IPPROTO_SCTP, | |
72 | .me = THIS_MODULE, | |
73 | .manip_pkt = sctp_manip_pkt, | |
74 | .in_range = nf_nat_proto_in_range, | |
75 | .unique_tuple = sctp_unique_tuple, | |
76 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) | |
77 | .range_to_nlattr = nf_nat_proto_range_to_nlattr, | |
78 | .nlattr_to_range = nf_nat_proto_nlattr_to_range, | |
79 | #endif | |
80 | }; | |
81 | ||
82 | static int __init nf_nat_proto_sctp_init(void) | |
83 | { | |
84 | return nf_nat_protocol_register(&nf_nat_protocol_sctp); | |
85 | } | |
86 | ||
87 | static void __exit nf_nat_proto_sctp_exit(void) | |
88 | { | |
89 | nf_nat_protocol_unregister(&nf_nat_protocol_sctp); | |
90 | } | |
91 | ||
92 | module_init(nf_nat_proto_sctp_init); | |
93 | module_exit(nf_nat_proto_sctp_exit); | |
94 | ||
95 | MODULE_LICENSE("GPL"); | |
96 | MODULE_DESCRIPTION("SCTP NAT protocol helper"); | |
97 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |