Patrick McHardy | b3f644f | 2012-08-26 19:14:14 +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 IPv6 MASQUERADE target. Development of IPv6 |
| 9 | * NAT funded by Astaro. |
| 10 | */ |
| 11 | |
| 12 | #include <linux/kernel.h> |
| 13 | #include <linux/module.h> |
| 14 | #include <linux/netdevice.h> |
| 15 | #include <linux/ipv6.h> |
| 16 | #include <linux/netfilter.h> |
| 17 | #include <linux/netfilter_ipv6.h> |
| 18 | #include <linux/netfilter/x_tables.h> |
| 19 | #include <net/netfilter/nf_nat.h> |
| 20 | #include <net/addrconf.h> |
| 21 | #include <net/ipv6.h> |
| 22 | |
| 23 | static unsigned int |
| 24 | masquerade_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
| 25 | { |
| 26 | const struct nf_nat_range *range = par->targinfo; |
| 27 | enum ip_conntrack_info ctinfo; |
| 28 | struct in6_addr src; |
| 29 | struct nf_conn *ct; |
| 30 | struct nf_nat_range newrange; |
| 31 | |
| 32 | ct = nf_ct_get(skb, &ctinfo); |
| 33 | NF_CT_ASSERT(ct && (ctinfo == IP_CT_NEW || ctinfo == IP_CT_RELATED || |
| 34 | ctinfo == IP_CT_RELATED_REPLY)); |
| 35 | |
| 36 | if (ipv6_dev_get_saddr(dev_net(par->out), par->out, |
| 37 | &ipv6_hdr(skb)->daddr, 0, &src) < 0) |
| 38 | return NF_DROP; |
| 39 | |
| 40 | nfct_nat(ct)->masq_index = par->out->ifindex; |
| 41 | |
| 42 | newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; |
| 43 | newrange.min_addr.in6 = src; |
| 44 | newrange.max_addr.in6 = src; |
| 45 | newrange.min_proto = range->min_proto; |
| 46 | newrange.max_proto = range->max_proto; |
| 47 | |
| 48 | return nf_nat_setup_info(ct, &newrange, NF_NAT_MANIP_SRC); |
| 49 | } |
| 50 | |
| 51 | static int masquerade_tg6_checkentry(const struct xt_tgchk_param *par) |
| 52 | { |
| 53 | const struct nf_nat_range *range = par->targinfo; |
| 54 | |
| 55 | if (range->flags & NF_NAT_RANGE_MAP_IPS) |
| 56 | return -EINVAL; |
| 57 | return 0; |
| 58 | } |
| 59 | |
| 60 | static int device_cmp(struct nf_conn *ct, void *ifindex) |
| 61 | { |
| 62 | const struct nf_conn_nat *nat = nfct_nat(ct); |
| 63 | |
| 64 | if (!nat) |
| 65 | return 0; |
| 66 | if (nf_ct_l3num(ct) != NFPROTO_IPV6) |
| 67 | return 0; |
| 68 | return nat->masq_index == (int)(long)ifindex; |
| 69 | } |
| 70 | |
| 71 | static int masq_device_event(struct notifier_block *this, |
| 72 | unsigned long event, void *ptr) |
| 73 | { |
| 74 | const struct net_device *dev = ptr; |
| 75 | struct net *net = dev_net(dev); |
| 76 | |
| 77 | if (event == NETDEV_DOWN) |
| 78 | nf_ct_iterate_cleanup(net, device_cmp, |
| 79 | (void *)(long)dev->ifindex); |
| 80 | |
| 81 | return NOTIFY_DONE; |
| 82 | } |
| 83 | |
| 84 | static struct notifier_block masq_dev_notifier = { |
| 85 | .notifier_call = masq_device_event, |
| 86 | }; |
| 87 | |
| 88 | static int masq_inet_event(struct notifier_block *this, |
| 89 | unsigned long event, void *ptr) |
| 90 | { |
| 91 | struct inet6_ifaddr *ifa = ptr; |
| 92 | |
| 93 | return masq_device_event(this, event, ifa->idev->dev); |
| 94 | } |
| 95 | |
| 96 | static struct notifier_block masq_inet_notifier = { |
| 97 | .notifier_call = masq_inet_event, |
| 98 | }; |
| 99 | |
| 100 | static struct xt_target masquerade_tg6_reg __read_mostly = { |
| 101 | .name = "MASQUERADE", |
| 102 | .family = NFPROTO_IPV6, |
| 103 | .checkentry = masquerade_tg6_checkentry, |
| 104 | .target = masquerade_tg6, |
| 105 | .targetsize = sizeof(struct nf_nat_range), |
| 106 | .table = "nat", |
| 107 | .hooks = 1 << NF_INET_POST_ROUTING, |
| 108 | .me = THIS_MODULE, |
| 109 | }; |
| 110 | |
| 111 | static int __init masquerade_tg6_init(void) |
| 112 | { |
| 113 | int err; |
| 114 | |
| 115 | err = xt_register_target(&masquerade_tg6_reg); |
| 116 | if (err == 0) { |
| 117 | register_netdevice_notifier(&masq_dev_notifier); |
| 118 | register_inet6addr_notifier(&masq_inet_notifier); |
| 119 | } |
| 120 | |
| 121 | return err; |
| 122 | } |
| 123 | static void __exit masquerade_tg6_exit(void) |
| 124 | { |
| 125 | unregister_inet6addr_notifier(&masq_inet_notifier); |
| 126 | unregister_netdevice_notifier(&masq_dev_notifier); |
| 127 | xt_unregister_target(&masquerade_tg6_reg); |
| 128 | } |
| 129 | |
| 130 | module_init(masquerade_tg6_init); |
| 131 | module_exit(masquerade_tg6_exit); |
| 132 | |
| 133 | MODULE_LICENSE("GPL"); |
| 134 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
| 135 | MODULE_DESCRIPTION("Xtables: automatic address SNAT"); |