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 <net/sctp/checksum.h>
15 #include <net/netfilter/nf_nat_protocol.h>
17 static u_int16_t nf_sctp_port_rover;
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)
25 return nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
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)
35 const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
37 unsigned int hdroff = iphdroff + iph->ihl*4;
41 if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
44 iph = (struct iphdr *)(skb->data + iphdroff);
45 hdr = (struct sctphdr *)(skb->data + hdroff);
47 if (maniptype == IP_NAT_MANIP_SRC) {
48 /* Get rid of src ip and src pt */
50 newip = tuple->src.u3.ip;
51 hdr->source = tuple->src.u.sctp.port;
53 /* Get rid of dst ip and dst pt */
55 newip = tuple->dst.u3.ip;
56 hdr->dest = tuple->dst.u.sctp.port;
59 crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
60 for (skb = skb_shinfo(skb)->frag_list; skb; skb = skb->next)
61 crc32 = sctp_update_cksum((u8 *)skb->data, skb_headlen(skb),
63 crc32 = sctp_end_cksum(crc32);
64 hdr->checksum = crc32;
69 static const struct nf_nat_protocol nf_nat_protocol_sctp = {
70 .protonum = IPPROTO_SCTP,
72 .manip_pkt = sctp_manip_pkt,
73 .in_range = nf_nat_proto_in_range,
74 .unique_tuple = sctp_unique_tuple,
75 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
76 .range_to_nlattr = nf_nat_proto_range_to_nlattr,
77 .nlattr_to_range = nf_nat_proto_nlattr_to_range,
81 static int __init nf_nat_proto_sctp_init(void)
83 return nf_nat_protocol_register(&nf_nat_protocol_sctp);
86 static void __exit nf_nat_proto_sctp_exit(void)
88 nf_nat_protocol_unregister(&nf_nat_protocol_sctp);
91 module_init(nf_nat_proto_sctp_init);
92 module_exit(nf_nat_proto_sctp_exit);
94 MODULE_LICENSE("GPL");
95 MODULE_DESCRIPTION("SCTP NAT protocol helper");
96 MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");