1 /* (C) 1999-2001 Paul `Rusty' Russell
2 * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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>
11 #include <linux/export.h>
13 #include <linux/icmp.h>
15 #include <linux/netfilter.h>
16 #include <net/netfilter/nf_nat.h>
17 #include <net/netfilter/nf_nat_core.h>
18 #include <net/netfilter/nf_nat_rule.h>
19 #include <net/netfilter/nf_nat_protocol.h>
22 icmp_in_range(const struct nf_conntrack_tuple *tuple,
23 enum nf_nat_manip_type maniptype,
24 const union nf_conntrack_man_proto *min,
25 const union nf_conntrack_man_proto *max)
27 return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) &&
28 ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id);
32 icmp_unique_tuple(struct nf_conntrack_tuple *tuple,
33 const struct nf_nat_range *range,
34 enum nf_nat_manip_type maniptype,
35 const struct nf_conn *ct)
38 unsigned int range_size;
41 range_size = ntohs(range->max.icmp.id) - ntohs(range->min.icmp.id) + 1;
42 /* If no range specified... */
43 if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED))
47 tuple->src.u.icmp.id = htons(ntohs(range->min.icmp.id) +
49 if (++i == range_size || !nf_nat_used_tuple(tuple, ct))
56 icmp_manip_pkt(struct sk_buff *skb,
57 unsigned int iphdroff,
58 const struct nf_conntrack_tuple *tuple,
59 enum nf_nat_manip_type maniptype)
61 const struct iphdr *iph = (struct iphdr *)(skb->data + iphdroff);
63 unsigned int hdroff = iphdroff + iph->ihl*4;
65 if (!skb_make_writable(skb, hdroff + sizeof(*hdr)))
68 hdr = (struct icmphdr *)(skb->data + hdroff);
69 inet_proto_csum_replace2(&hdr->checksum, skb,
70 hdr->un.echo.id, tuple->src.u.icmp.id, 0);
71 hdr->un.echo.id = tuple->src.u.icmp.id;
75 const struct nf_nat_protocol nf_nat_protocol_icmp = {
76 .protonum = IPPROTO_ICMP,
78 .manip_pkt = icmp_manip_pkt,
79 .in_range = icmp_in_range,
80 .unique_tuple = icmp_unique_tuple,
81 #if defined(CONFIG_NF_CT_NETLINK) || defined(CONFIG_NF_CT_NETLINK_MODULE)
82 .range_to_nlattr = nf_nat_proto_range_to_nlattr,
83 .nlattr_to_range = nf_nat_proto_nlattr_to_range,