2 * Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
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.
9 #include <linux/types.h>
10 #include <linux/init.h>
12 #include <linux/sctp.h>
13 #include <linux/module.h>
14 #include <net/sctp/checksum.h>
16 #include <net/netfilter/nf_nat_protocol.h>
18 static u_int16_t nf_sctp_port_rover;
21 sctp_unique_tuple(struct nf_conntrack_tuple *tuple,
22 const struct nf_nat_range *range,
23 enum nf_nat_manip_type maniptype,
24 const struct nf_conn *ct)
26 nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
31 sctp_manip_pkt(struct sk_buff *skb,
32 unsigned int iphdroff,
33 const struct nf_conntrack_tuple *tuple,
34 enum nf_nat_manip_type maniptype)
36 const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
39 unsigned int hdroff = iphdroff + iph->ihl*4;
43 if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
46 iph = (struct iphdr *)(skb->data + iphdroff);
47 hdr = (struct sctphdr *)(skb->data + hdroff);
49 if (maniptype == IP_NAT_MANIP_SRC) {
50 /* Get rid of src ip and src pt */
52 newip = tuple->src.u3.ip;
53 hdr->source = tuple->src.u.sctp.port;
55 /* Get rid of dst ip and dst pt */
57 newip = tuple->dst.u3.ip;
58 hdr->dest = tuple->dst.u.sctp.port;
61 crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
62 skb_walk_frags(skb, frag)
63 crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag),
65 crc32 = sctp_end_cksum(crc32);
66 hdr->checksum = crc32;
71 static const struct nf_nat_protocol nf_nat_protocol_sctp = {
72 .protonum = IPPROTO_SCTP,
74 .manip_pkt = sctp_manip_pkt,
75 .in_range = nf_nat_proto_in_range,
76 .unique_tuple = sctp_unique_tuple,
77 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
78 .range_to_nlattr = nf_nat_proto_range_to_nlattr,
79 .nlattr_to_range = nf_nat_proto_nlattr_to_range,
83 static int __init nf_nat_proto_sctp_init(void)
85 return nf_nat_protocol_register(&nf_nat_protocol_sctp);
88 static void __exit nf_nat_proto_sctp_exit(void)
90 nf_nat_protocol_unregister(&nf_nat_protocol_sctp);
93 module_init(nf_nat_proto_sctp_init);
94 module_exit(nf_nat_proto_sctp_exit);
96 MODULE_LICENSE("GPL");
97 MODULE_DESCRIPTION("SCTP NAT protocol helper");
98 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");