summaryrefslogtreecommitdiff
path: root/net/ipv4/netfilter/nf_nat_proto_icmp.c
blob: 4fecb3f2c55ad6d6ce33f1d6f457d5e69766cba9 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
/* (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_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,
};