Patrick McHardy | 58a317f | 2012-08-26 19:14:12 +0200 | [diff] [blame] | 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); |
| 72 | if (hdr->icmp6_code == ICMPV6_ECHO_REQUEST || |
| 73 | hdr->icmp6_code == ICMPV6_ECHO_REPLY) { |
| 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, |
Amerigo Wang | 07a9362 | 2012-10-29 16:23:10 +0000 | [diff] [blame] | 87 | #if IS_ENABLED(CONFIG_NF_CT_NETLINK) |
Patrick McHardy | 58a317f | 2012-08-26 19:14:12 +0200 | [diff] [blame] | 88 | .nlattr_to_range = nf_nat_l4proto_nlattr_to_range, |
| 89 | #endif |
| 90 | }; |