Commit | Line | Data |
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1da177e4 LT |
1 | /* (C) 1999-2001 Paul `Rusty' Russell |
2 | * (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org> | |
3 | * | |
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. | |
7 | */ | |
8 | ||
9 | #include <linux/types.h> | |
10 | #include <linux/init.h> | |
11 | #include <linux/netfilter.h> | |
12 | #include <linux/ip.h> | |
13 | #include <linux/icmp.h> | |
14 | #include <linux/if.h> | |
15 | ||
16 | #include <linux/netfilter_ipv4/ip_nat.h> | |
17 | #include <linux/netfilter_ipv4/ip_nat_core.h> | |
18 | #include <linux/netfilter_ipv4/ip_nat_rule.h> | |
19 | #include <linux/netfilter_ipv4/ip_nat_protocol.h> | |
20 | ||
21 | static int | |
22 | icmp_in_range(const struct ip_conntrack_tuple *tuple, | |
23 | enum ip_nat_manip_type maniptype, | |
24 | const union ip_conntrack_manip_proto *min, | |
25 | const union ip_conntrack_manip_proto *max) | |
26 | { | |
bff9a89b PM |
27 | return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) && |
28 | ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id); | |
1da177e4 LT |
29 | } |
30 | ||
31 | static int | |
32 | icmp_unique_tuple(struct ip_conntrack_tuple *tuple, | |
33 | const struct ip_nat_range *range, | |
34 | enum ip_nat_manip_type maniptype, | |
35 | const struct ip_conntrack *conntrack) | |
36 | { | |
37 | static u_int16_t id; | |
74bb421d | 38 | unsigned int range_size; |
1da177e4 LT |
39 | unsigned int i; |
40 | ||
74bb421d | 41 | range_size = ntohs(range->max.icmp.id) - ntohs(range->min.icmp.id) + 1; |
1da177e4 LT |
42 | /* If no range specified... */ |
43 | if (!(range->flags & IP_NAT_RANGE_PROTO_SPECIFIED)) | |
44 | range_size = 0xFFFF; | |
45 | ||
46 | for (i = 0; i < range_size; i++, id++) { | |
74bb421d | 47 | tuple->src.u.icmp.id = htons(ntohs(range->min.icmp.id) + |
e905a9ed | 48 | (id % range_size)); |
1da177e4 LT |
49 | if (!ip_nat_used_tuple(tuple, conntrack)) |
50 | return 1; | |
51 | } | |
52 | return 0; | |
53 | } | |
54 | ||
55 | static int | |
56 | icmp_manip_pkt(struct sk_buff **pskb, | |
57 | unsigned int iphdroff, | |
58 | const struct ip_conntrack_tuple *tuple, | |
59 | enum ip_nat_manip_type maniptype) | |
60 | { | |
61 | struct iphdr *iph = (struct iphdr *)((*pskb)->data + iphdroff); | |
62 | struct icmphdr *hdr; | |
63 | unsigned int hdroff = iphdroff + iph->ihl*4; | |
64 | ||
089af26c | 65 | if (!skb_make_writable(pskb, hdroff + sizeof(*hdr))) |
1da177e4 LT |
66 | return 0; |
67 | ||
68 | hdr = (struct icmphdr *)((*pskb)->data + hdroff); | |
43bc0ca7 AV |
69 | nf_proto_csum_replace2(&hdr->checksum, *pskb, |
70 | hdr->un.echo.id, tuple->src.u.icmp.id, 0); | |
1da177e4 LT |
71 | hdr->un.echo.id = tuple->src.u.icmp.id; |
72 | return 1; | |
73 | } | |
74 | ||
373ac735 PM |
75 | struct ip_nat_protocol ip_nat_protocol_icmp = { |
76 | .name = "ICMP", | |
77 | .protonum = IPPROTO_ICMP, | |
78 | .me = THIS_MODULE, | |
79 | .manip_pkt = icmp_manip_pkt, | |
80 | .in_range = icmp_in_range, | |
81 | .unique_tuple = icmp_unique_tuple, | |
080774a2 HW |
82 | #if defined(CONFIG_IP_NF_CONNTRACK_NETLINK) || \ |
83 | defined(CONFIG_IP_NF_CONNTRACK_NETLINK_MODULE) | |
373ac735 PM |
84 | .range_to_nfattr = ip_nat_port_range_to_nfattr, |
85 | .nfattr_to_range = ip_nat_port_nfattr_to_range, | |
080774a2 | 86 | #endif |
1da177e4 | 87 | }; |