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/*
* 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/sctp.h>
#include <net/sctp/checksum.h>
#include <net/netfilter/nf_nat_l4proto.h>
static u_int16_t nf_sctp_port_rover;
static void
sctp_unique_tuple(const struct nf_nat_l3proto *l3proto,
struct nf_conntrack_tuple *tuple,
const struct nf_nat_range2 *range,
enum nf_nat_manip_type maniptype,
const struct nf_conn *ct)
{
nf_nat_l4proto_unique_tuple(l3proto, tuple, range, maniptype, ct,
&nf_sctp_port_rover);
}
static bool
sctp_manip_pkt(struct sk_buff *skb,
const struct nf_nat_l3proto *l3proto,
unsigned int iphdroff, unsigned int hdroff,
const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype)
{
struct sctphdr *hdr;
int hdrsize = 8;
/* This could be an inner header returned in imcp packet; in such
* cases we cannot update the checksum field since it is outside
* of the 8 bytes of transport layer headers we are guaranteed.
*/
if (skb->len >= hdroff + sizeof(*hdr))
hdrsize = sizeof(*hdr);
if (!skb_make_writable(skb, hdroff + hdrsize))
return false;
hdr = (struct sctphdr *)(skb->data + hdroff);
if (maniptype == NF_NAT_MANIP_SRC) {
/* Get rid of src port */
hdr->source = tuple->src.u.sctp.port;
} else {
/* Get rid of dst port */
hdr->dest = tuple->dst.u.sctp.port;
}
if (hdrsize < sizeof(*hdr))
return true;
if (skb->ip_summed != CHECKSUM_PARTIAL) {
hdr->checksum = sctp_compute_cksum(skb, hdroff);
skb->ip_summed = CHECKSUM_NONE;
}
return true;
}
const struct nf_nat_l4proto nf_nat_l4proto_sctp = {
.l4proto = IPPROTO_SCTP,
.manip_pkt = sctp_manip_pkt,
.in_range = nf_nat_l4proto_in_range,
.unique_tuple = sctp_unique_tuple,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
#endif
};
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