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/* (C) 1999-2001 Paul `Rusty' Russell
* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
*
* 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/export.h>
#include <linux/ip.h>
#include <linux/icmp.h>
#include <linux/netfilter.h>
#include <net/netfilter/nf_nat.h>
#include <net/netfilter/nf_nat_core.h>
#include <net/netfilter/nf_nat_l4proto.h>
static bool
icmp_in_range(const struct nf_conntrack_tuple *tuple,
enum nf_nat_manip_type maniptype,
const union nf_conntrack_man_proto *min,
const union nf_conntrack_man_proto *max)
{
return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
}
static bool
icmp_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 icmphdr *hdr;
if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
return false;
hdr = (struct icmphdr *)(skb->data + hdroff);
inet_proto_csum_replace2(&hdr->checksum, skb,
hdr->un.echo.id, tuple->src.u.icmp.id, false);
hdr->un.echo.id = tuple->src.u.icmp.id;
return true;
}
const struct nf_nat_l4proto nf_nat_l4proto_icmp = {
.l4proto = IPPROTO_ICMP,
.manip_pkt = icmp_manip_pkt,
.in_range = icmp_in_range,
#if IS_ENABLED(CONFIG_NF_CT_NETLINK)
.nlattr_to_range = nf_nat_l4proto_nlattr_to_range,
#endif
};
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