Jan Engelhardt | b3d54b3 | 2012-09-21 11:37:59 +0200 | [diff] [blame] | 1 | /* |
| 2 | * (C) 2000-2001 Svenning Soerensen <svenning@post5.tele.dk> |
| 3 | * Copyright (c) 2011 Patrick McHardy <kaber@trash.net> |
| 4 | * |
| 5 | * This program is free software; you can redistribute it and/or modify |
| 6 | * it under the terms of the GNU General Public License version 2 as |
| 7 | * published by the Free Software Foundation. |
| 8 | */ |
| 9 | |
| 10 | #include <linux/ip.h> |
| 11 | #include <linux/kernel.h> |
| 12 | #include <linux/module.h> |
| 13 | #include <linux/netdevice.h> |
| 14 | #include <linux/ipv6.h> |
| 15 | #include <linux/netfilter.h> |
| 16 | #include <linux/netfilter_ipv4.h> |
| 17 | #include <linux/netfilter_ipv6.h> |
| 18 | #include <linux/netfilter/x_tables.h> |
| 19 | #include <net/netfilter/nf_nat.h> |
| 20 | |
| 21 | static unsigned int |
| 22 | netmap_tg6(struct sk_buff *skb, const struct xt_action_param *par) |
| 23 | { |
| 24 | const struct nf_nat_range *range = par->targinfo; |
| 25 | struct nf_nat_range newrange; |
| 26 | struct nf_conn *ct; |
| 27 | enum ip_conntrack_info ctinfo; |
| 28 | union nf_inet_addr new_addr, netmask; |
| 29 | unsigned int i; |
| 30 | |
| 31 | ct = nf_ct_get(skb, &ctinfo); |
| 32 | for (i = 0; i < ARRAY_SIZE(range->min_addr.ip6); i++) |
| 33 | netmask.ip6[i] = ~(range->min_addr.ip6[i] ^ |
| 34 | range->max_addr.ip6[i]); |
| 35 | |
| 36 | if (par->hooknum == NF_INET_PRE_ROUTING || |
| 37 | par->hooknum == NF_INET_LOCAL_OUT) |
| 38 | new_addr.in6 = ipv6_hdr(skb)->daddr; |
| 39 | else |
| 40 | new_addr.in6 = ipv6_hdr(skb)->saddr; |
| 41 | |
| 42 | for (i = 0; i < ARRAY_SIZE(new_addr.ip6); i++) { |
| 43 | new_addr.ip6[i] &= ~netmask.ip6[i]; |
| 44 | new_addr.ip6[i] |= range->min_addr.ip6[i] & |
| 45 | netmask.ip6[i]; |
| 46 | } |
| 47 | |
| 48 | newrange.flags = range->flags | NF_NAT_RANGE_MAP_IPS; |
| 49 | newrange.min_addr = new_addr; |
| 50 | newrange.max_addr = new_addr; |
| 51 | newrange.min_proto = range->min_proto; |
| 52 | newrange.max_proto = range->max_proto; |
| 53 | |
| 54 | return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum)); |
| 55 | } |
| 56 | |
| 57 | static int netmap_tg6_checkentry(const struct xt_tgchk_param *par) |
| 58 | { |
| 59 | const struct nf_nat_range *range = par->targinfo; |
| 60 | |
| 61 | if (!(range->flags & NF_NAT_RANGE_MAP_IPS)) |
| 62 | return -EINVAL; |
| 63 | return 0; |
| 64 | } |
| 65 | |
| 66 | static unsigned int |
| 67 | netmap_tg4(struct sk_buff *skb, const struct xt_action_param *par) |
| 68 | { |
| 69 | struct nf_conn *ct; |
| 70 | enum ip_conntrack_info ctinfo; |
| 71 | __be32 new_ip, netmask; |
| 72 | const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo; |
| 73 | struct nf_nat_range newrange; |
| 74 | |
| 75 | NF_CT_ASSERT(par->hooknum == NF_INET_PRE_ROUTING || |
| 76 | par->hooknum == NF_INET_POST_ROUTING || |
| 77 | par->hooknum == NF_INET_LOCAL_OUT || |
| 78 | par->hooknum == NF_INET_LOCAL_IN); |
| 79 | ct = nf_ct_get(skb, &ctinfo); |
| 80 | |
| 81 | netmask = ~(mr->range[0].min_ip ^ mr->range[0].max_ip); |
| 82 | |
| 83 | if (par->hooknum == NF_INET_PRE_ROUTING || |
| 84 | par->hooknum == NF_INET_LOCAL_OUT) |
| 85 | new_ip = ip_hdr(skb)->daddr & ~netmask; |
| 86 | else |
| 87 | new_ip = ip_hdr(skb)->saddr & ~netmask; |
| 88 | new_ip |= mr->range[0].min_ip & netmask; |
| 89 | |
| 90 | memset(&newrange.min_addr, 0, sizeof(newrange.min_addr)); |
| 91 | memset(&newrange.max_addr, 0, sizeof(newrange.max_addr)); |
| 92 | newrange.flags = mr->range[0].flags | NF_NAT_RANGE_MAP_IPS; |
| 93 | newrange.min_addr.ip = new_ip; |
| 94 | newrange.max_addr.ip = new_ip; |
| 95 | newrange.min_proto = mr->range[0].min; |
| 96 | newrange.max_proto = mr->range[0].max; |
| 97 | |
| 98 | /* Hand modified range to generic setup. */ |
| 99 | return nf_nat_setup_info(ct, &newrange, HOOK2MANIP(par->hooknum)); |
| 100 | } |
| 101 | |
| 102 | static int netmap_tg4_check(const struct xt_tgchk_param *par) |
| 103 | { |
| 104 | const struct nf_nat_ipv4_multi_range_compat *mr = par->targinfo; |
| 105 | |
| 106 | if (!(mr->range[0].flags & NF_NAT_RANGE_MAP_IPS)) { |
| 107 | pr_debug("bad MAP_IPS.\n"); |
| 108 | return -EINVAL; |
| 109 | } |
| 110 | if (mr->rangesize != 1) { |
| 111 | pr_debug("bad rangesize %u.\n", mr->rangesize); |
| 112 | return -EINVAL; |
| 113 | } |
| 114 | return 0; |
| 115 | } |
| 116 | |
| 117 | static struct xt_target netmap_tg_reg[] __read_mostly = { |
| 118 | { |
| 119 | .name = "NETMAP", |
| 120 | .family = NFPROTO_IPV6, |
| 121 | .revision = 0, |
| 122 | .target = netmap_tg6, |
| 123 | .targetsize = sizeof(struct nf_nat_range), |
| 124 | .table = "nat", |
| 125 | .hooks = (1 << NF_INET_PRE_ROUTING) | |
| 126 | (1 << NF_INET_POST_ROUTING) | |
| 127 | (1 << NF_INET_LOCAL_OUT) | |
| 128 | (1 << NF_INET_LOCAL_IN), |
| 129 | .checkentry = netmap_tg6_checkentry, |
| 130 | .me = THIS_MODULE, |
| 131 | }, |
| 132 | { |
| 133 | .name = "NETMAP", |
| 134 | .family = NFPROTO_IPV4, |
| 135 | .revision = 0, |
| 136 | .target = netmap_tg4, |
| 137 | .targetsize = sizeof(struct nf_nat_ipv4_multi_range_compat), |
| 138 | .table = "nat", |
| 139 | .hooks = (1 << NF_INET_PRE_ROUTING) | |
| 140 | (1 << NF_INET_POST_ROUTING) | |
| 141 | (1 << NF_INET_LOCAL_OUT) | |
| 142 | (1 << NF_INET_LOCAL_IN), |
| 143 | .checkentry = netmap_tg4_check, |
| 144 | .me = THIS_MODULE, |
| 145 | }, |
| 146 | }; |
| 147 | |
| 148 | static int __init netmap_tg_init(void) |
| 149 | { |
| 150 | return xt_register_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg)); |
| 151 | } |
| 152 | |
| 153 | static void netmap_tg_exit(void) |
| 154 | { |
| 155 | xt_unregister_targets(netmap_tg_reg, ARRAY_SIZE(netmap_tg_reg)); |
| 156 | } |
| 157 | |
| 158 | module_init(netmap_tg_init); |
| 159 | module_exit(netmap_tg_exit); |
| 160 | |
| 161 | MODULE_LICENSE("GPL"); |
| 162 | MODULE_DESCRIPTION("Xtables: 1:1 NAT mapping of subnets"); |
| 163 | MODULE_AUTHOR("Patrick McHardy <kaber@trash.net>"); |
| 164 | MODULE_ALIAS("ip6t_NETMAP"); |
| 165 | MODULE_ALIAS("ipt_NETMAP"); |