98 lines
2.6 KiB
C
98 lines
2.6 KiB
C
/*
|
|
* Copyright (c) 2008 Patrick McHardy <kaber@trash.net>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License version 2 as
|
|
* published by the Free Software Foundation.
|
|
*/
|
|
|
|
#include <linux/types.h>
|
|
#include <linux/init.h>
|
|
#include <linux/ip.h>
|
|
#include <linux/sctp.h>
|
|
#include <net/sctp/checksum.h>
|
|
|
|
#include <net/netfilter/nf_nat_protocol.h>
|
|
|
|
static u_int16_t nf_sctp_port_rover;
|
|
|
|
static bool
|
|
sctp_unique_tuple(struct nf_conntrack_tuple *tuple,
|
|
const struct nf_nat_range *range,
|
|
enum nf_nat_manip_type maniptype,
|
|
const struct nf_conn *ct)
|
|
{
|
|
return nf_nat_proto_unique_tuple(tuple, range, maniptype, ct,
|
|
&nf_sctp_port_rover);
|
|
}
|
|
|
|
static bool
|
|
sctp_manip_pkt(struct sk_buff *skb,
|
|
unsigned int iphdroff,
|
|
const struct nf_conntrack_tuple *tuple,
|
|
enum nf_nat_manip_type maniptype)
|
|
{
|
|
const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
|
|
struct sk_buff *frag;
|
|
sctp_sctphdr_t *hdr;
|
|
unsigned int hdroff = iphdroff + iph->ihl*4;
|
|
__be32 oldip, newip;
|
|
__be32 crc32;
|
|
|
|
if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
|
|
return false;
|
|
|
|
iph = (struct iphdr *)(skb->data + iphdroff);
|
|
hdr = (struct sctphdr *)(skb->data + hdroff);
|
|
|
|
if (maniptype == IP_NAT_MANIP_SRC) {
|
|
/* Get rid of src ip and src pt */
|
|
oldip = iph->saddr;
|
|
newip = tuple->src.u3.ip;
|
|
hdr->source = tuple->src.u.sctp.port;
|
|
} else {
|
|
/* Get rid of dst ip and dst pt */
|
|
oldip = iph->daddr;
|
|
newip = tuple->dst.u3.ip;
|
|
hdr->dest = tuple->dst.u.sctp.port;
|
|
}
|
|
|
|
crc32 = sctp_start_cksum((u8 *)hdr, skb_headlen(skb) - hdroff);
|
|
skb_walk_frags(skb, frag);
|
|
crc32 = sctp_update_cksum((u8 *)frag->data, skb_headlen(frag),
|
|
crc32);
|
|
crc32 = sctp_end_cksum(crc32);
|
|
hdr->checksum = crc32;
|
|
|
|
return true;
|
|
}
|
|
|
|
static const struct nf_nat_protocol nf_nat_protocol_sctp = {
|
|
.protonum = IPPROTO_SCTP,
|
|
.me = THIS_MODULE,
|
|
.manip_pkt = sctp_manip_pkt,
|
|
.in_range = nf_nat_proto_in_range,
|
|
.unique_tuple = sctp_unique_tuple,
|
|
#if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
|
|
.range_to_nlattr = nf_nat_proto_range_to_nlattr,
|
|
.nlattr_to_range = nf_nat_proto_nlattr_to_range,
|
|
#endif
|
|
};
|
|
|
|
static int __init nf_nat_proto_sctp_init(void)
|
|
{
|
|
return nf_nat_protocol_register(&nf_nat_protocol_sctp);
|
|
}
|
|
|
|
static void __exit nf_nat_proto_sctp_exit(void)
|
|
{
|
|
nf_nat_protocol_unregister(&nf_nat_protocol_sctp);
|
|
}
|
|
|
|
module_init(nf_nat_proto_sctp_init);
|
|
module_exit(nf_nat_proto_sctp_exit);
|
|
|
|
MODULE_LICENSE("GPL");
|
|
MODULE_DESCRIPTION("SCTP NAT protocol helper");
|
|
MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>");
|