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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> | |
9d908a69 | 11 | #include <linux/sctp.h> |
3a9a231d | 12 | #include <linux/module.h> |
9d908a69 PM |
13 | #include <net/sctp/checksum.h> |
14 | ||
c7232c99 | 15 | #include <net/netfilter/nf_nat_l4proto.h> |
9d908a69 PM |
16 | |
17 | static u_int16_t nf_sctp_port_rover; | |
18 | ||
f43dc98b | 19 | static void |
c7232c99 PM |
20 | sctp_unique_tuple(const struct nf_nat_l3proto *l3proto, |
21 | struct nf_conntrack_tuple *tuple, | |
22 | const struct nf_nat_range *range, | |
9d908a69 PM |
23 | enum nf_nat_manip_type maniptype, |
24 | const struct nf_conn *ct) | |
25 | { | |
c7232c99 PM |
26 | nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct, |
27 | &nf_sctp_port_rover); | |
9d908a69 PM |
28 | } |
29 | ||
f2ea825f | 30 | static bool |
9d908a69 | 31 | sctp_manip_pkt(struct sk_buff *skb, |
c7232c99 PM |
32 | const struct nf_nat_l3proto *l3proto, |
33 | unsigned int iphdroff, unsigned int hdroff, | |
9d908a69 PM |
34 | const struct nf_conntrack_tuple *tuple, |
35 | enum nf_nat_manip_type maniptype) | |
36 | { | |
343a9972 | 37 | struct sk_buff *frag; |
9d908a69 | 38 | sctp_sctphdr_t *hdr; |
336d3262 | 39 | __be32 crc32; |
9d908a69 PM |
40 | |
41 | if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) | |
f2ea825f | 42 | return false; |
9d908a69 | 43 | |
9d908a69 PM |
44 | hdr = (struct sctphdr *)(skb->data + hdroff); |
45 | ||
cbc9f2f4 | 46 | if (maniptype == NF_NAT_MANIP_SRC) { |
c7232c99 | 47 | /* Get rid of src port */ |
9d908a69 PM |
48 | hdr->source = tuple->src.u.sctp.port; |
49 | } else { | |
c7232c99 | 50 | /* Get rid of dst port */ |
9d908a69 PM |
51 | hdr->dest = tuple->dst.u.sctp.port; |
52 | } | |
53 | ||
54 | crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff); | |
0808dc80 | 55 | skb_walk_frags(skb, frag) |
343a9972 | 56 | crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag), |
9d908a69 PM |
57 | crc32); |
58 | crc32 = sctp_end_cksum(crc32); | |
336d3262 | 59 | hdr->checksum = crc32; |
9d908a69 | 60 | |
f2ea825f | 61 | return true; |
9d908a69 PM |
62 | } |
63 | ||
c7232c99 PM |
64 | static const struct nf_nat_l4proto nf_nat_l4proto_sctp = { |
65 | .l4proto = IPPROTO_SCTP, | |
9d908a69 | 66 | .manip_pkt = sctp_manip_pkt, |
c7232c99 | 67 | .in_range = nf_nat_l4proto_in_range, |
9d908a69 PM |
68 | .unique_tuple = sctp_unique_tuple, |
69 | #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE) | |
c7232c99 | 70 | .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, |
9d908a69 PM |
71 | #endif |
72 | }; | |
73 | ||
74 | static int __init nf_nat_proto_sctp_init(void) | |
75 | { | |
c7232c99 PM |
76 | int err; |
77 | ||
78 | err = nf_nat_l4proto_register(NFPROTO_IPV4, &nf_nat_l4proto_sctp); | |
79 | if (err < 0) | |
80 | goto err1; | |
81 | err = nf_nat_l4proto_register(NFPROTO_IPV6, &nf_nat_l4proto_sctp); | |
82 | if (err < 0) | |
83 | goto err2; | |
84 | return 0; | |
85 | ||
86 | err2: | |
87 | nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp); | |
88 | err1: | |
89 | return err; | |
9d908a69 PM |
90 | } |
91 | ||
92 | static void __exit nf_nat_proto_sctp_exit(void) | |
93 | { | |
c7232c99 PM |
94 | nf_nat_l4proto_unregister(NFPROTO_IPV6, &nf_nat_l4proto_sctp); |
95 | nf_nat_l4proto_unregister(NFPROTO_IPV4, &nf_nat_l4proto_sctp); | |
9d908a69 PM |
96 | } |
97 | ||
98 | module_init(nf_nat_proto_sctp_init); | |
99 | module_exit(nf_nat_proto_sctp_exit); | |
100 | ||
101 | MODULE_LICENSE("GPL"); | |
102 | MODULE_DESCRIPTION("SCTP NAT protocol helper"); | |
103 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |