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58a317f1 PM |
1 | /* |
2 | * Copyright (c) 2011 Patrick Mchardy <kaber@trash.net> | |
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 | * Based on Rusty Russell's IPv4 ICMP NAT code. Development of IPv6 | |
9 | * NAT funded by Astaro. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/init.h> | |
14 | #include <linux/icmpv6.h> | |
15 | ||
16 | #include <linux/netfilter.h> | |
17 | #include <net/netfilter/nf_nat.h> | |
18 | #include <net/netfilter/nf_nat_core.h> | |
19 | #include <net/netfilter/nf_nat_l3proto.h> | |
20 | #include <net/netfilter/nf_nat_l4proto.h> | |
21 | ||
22 | static bool | |
23 | icmpv6_in_range(const struct nf_conntrack_tuple *tuple, | |
24 | enum nf_nat_manip_type maniptype, | |
25 | const union nf_conntrack_man_proto *min, | |
26 | const union nf_conntrack_man_proto *max) | |
27 | { | |
28 | return ntohs(tuple->src.u.icmp.id) >= ntohs(min->icmp.id) && | |
29 | ntohs(tuple->src.u.icmp.id) <= ntohs(max->icmp.id); | |
30 | } | |
31 | ||
32 | static void | |
33 | icmpv6_unique_tuple(const struct nf_nat_l3proto *l3proto, | |
34 | struct nf_conntrack_tuple *tuple, | |
35 | const struct nf_nat_range *range, | |
36 | enum nf_nat_manip_type maniptype, | |
37 | const struct nf_conn *ct) | |
38 | { | |
39 | static u16 id; | |
40 | unsigned int range_size; | |
41 | unsigned int i; | |
42 | ||
43 | range_size = ntohs(range->max_proto.icmp.id) - | |
44 | ntohs(range->min_proto.icmp.id) + 1; | |
45 | ||
46 | if (!(range->flags & NF_NAT_RANGE_PROTO_SPECIFIED)) | |
47 | range_size = 0xffff; | |
48 | ||
49 | for (i = 0; ; ++id) { | |
50 | tuple->src.u.icmp.id = htons(ntohs(range->min_proto.icmp.id) + | |
51 | (id % range_size)); | |
52 | if (++i == range_size || !nf_nat_used_tuple(tuple, ct)) | |
53 | return; | |
54 | } | |
55 | } | |
56 | ||
57 | static bool | |
58 | icmpv6_manip_pkt(struct sk_buff *skb, | |
59 | const struct nf_nat_l3proto *l3proto, | |
60 | unsigned int iphdroff, unsigned int hdroff, | |
61 | const struct nf_conntrack_tuple *tuple, | |
62 | enum nf_nat_manip_type maniptype) | |
63 | { | |
64 | struct icmp6hdr *hdr; | |
65 | ||
66 | if (!skb_make_writable(skb, hdroff + sizeof(*hdr))) | |
67 | return false; | |
68 | ||
69 | hdr = (struct icmp6hdr *)(skb->data + hdroff); | |
70 | l3proto->csum_update(skb, iphdroff, &hdr->icmp6_cksum, | |
71 | tuple, maniptype); | |
d830f0fa PO |
72 | if (hdr->icmp6_type == ICMPV6_ECHO_REQUEST || |
73 | hdr->icmp6_type == ICMPV6_ECHO_REPLY) { | |
58a317f1 PM |
74 | inet_proto_csum_replace2(&hdr->icmp6_cksum, skb, |
75 | hdr->icmp6_identifier, | |
76 | tuple->src.u.icmp.id, 0); | |
77 | hdr->icmp6_identifier = tuple->src.u.icmp.id; | |
78 | } | |
79 | return true; | |
80 | } | |
81 | ||
82 | const struct nf_nat_l4proto nf_nat_l4proto_icmpv6 = { | |
83 | .l4proto = IPPROTO_ICMPV6, | |
84 | .manip_pkt = icmpv6_manip_pkt, | |
85 | .in_range = icmpv6_in_range, | |
86 | .unique_tuple = icmpv6_unique_tuple, | |
07a93626 | 87 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
58a317f1 PM |
88 | .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, |
89 | #endif | |
90 | }; |