Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (c) 2010 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 | |
| 9 | #include <linux/module.h> |
| 10 | #include <linux/skbuff.h> |
| 11 | #include <linux/selinux.h> |
| 12 | #include <linux/netfilter_ipv4/ip_tables.h> |
| 13 | #include <linux/netfilter_ipv6/ip6_tables.h> |
| 14 | #include <linux/netfilter/x_tables.h> |
| 15 | #include <linux/netfilter/xt_CT.h> |
| 16 | #include <net/netfilter/nf_conntrack.h> |
| 17 | #include <net/netfilter/nf_conntrack_helper.h> |
| 18 | #include <net/netfilter/nf_conntrack_ecache.h> |
Patrick McHardy | 5d0aa2c | 2010-02-15 18:13:33 +0100 | [diff] [blame] | 19 | #include <net/netfilter/nf_conntrack_zones.h> |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 20 | |
| 21 | static unsigned int xt_ct_target(struct sk_buff *skb, |
| 22 | const struct xt_target_param *par) |
| 23 | { |
| 24 | const struct xt_ct_target_info *info = par->targinfo; |
| 25 | struct nf_conn *ct = info->ct; |
| 26 | |
| 27 | /* Previously seen (loopback)? Ignore. */ |
| 28 | if (skb->nfct != NULL) |
| 29 | return XT_CONTINUE; |
| 30 | |
| 31 | atomic_inc(&ct->ct_general.use); |
| 32 | skb->nfct = &ct->ct_general; |
| 33 | skb->nfctinfo = IP_CT_NEW; |
| 34 | |
| 35 | return XT_CONTINUE; |
| 36 | } |
| 37 | |
| 38 | static u8 xt_ct_find_proto(const struct xt_tgchk_param *par) |
| 39 | { |
Jan Engelhardt | 076f783 | 2010-03-11 00:38:44 +0100 | [diff] [blame^] | 40 | if (par->family == NFPROTO_IPV4) { |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 41 | const struct ipt_entry *e = par->entryinfo; |
| 42 | |
| 43 | if (e->ip.invflags & IPT_INV_PROTO) |
| 44 | return 0; |
| 45 | return e->ip.proto; |
Jan Engelhardt | 076f783 | 2010-03-11 00:38:44 +0100 | [diff] [blame^] | 46 | } else if (par->family == NFPROTO_IPV6) { |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 47 | const struct ip6t_entry *e = par->entryinfo; |
| 48 | |
| 49 | if (e->ipv6.invflags & IP6T_INV_PROTO) |
| 50 | return 0; |
| 51 | return e->ipv6.proto; |
| 52 | } else |
| 53 | return 0; |
| 54 | } |
| 55 | |
| 56 | static bool xt_ct_tg_check(const struct xt_tgchk_param *par) |
| 57 | { |
| 58 | struct xt_ct_target_info *info = par->targinfo; |
| 59 | struct nf_conntrack_tuple t; |
| 60 | struct nf_conn_help *help; |
| 61 | struct nf_conn *ct; |
| 62 | u8 proto; |
| 63 | |
| 64 | if (info->flags & ~XT_CT_NOTRACK) |
| 65 | return false; |
| 66 | |
| 67 | if (info->flags & XT_CT_NOTRACK) { |
| 68 | ct = &nf_conntrack_untracked; |
| 69 | atomic_inc(&ct->ct_general.use); |
| 70 | goto out; |
| 71 | } |
| 72 | |
Patrick McHardy | 5d0aa2c | 2010-02-15 18:13:33 +0100 | [diff] [blame] | 73 | #ifndef CONFIG_NF_CONNTRACK_ZONES |
| 74 | if (info->zone) |
| 75 | goto err1; |
| 76 | #endif |
| 77 | |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 78 | if (nf_ct_l3proto_try_module_get(par->family) < 0) |
| 79 | goto err1; |
| 80 | |
| 81 | memset(&t, 0, sizeof(t)); |
Patrick McHardy | 5d0aa2c | 2010-02-15 18:13:33 +0100 | [diff] [blame] | 82 | ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL); |
Patrick McHardy | 84f3bb9 | 2010-02-03 17:17:06 +0100 | [diff] [blame] | 83 | if (IS_ERR(ct)) |
| 84 | goto err2; |
| 85 | |
| 86 | if ((info->ct_events || info->exp_events) && |
| 87 | !nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events, |
| 88 | GFP_KERNEL)) |
| 89 | goto err3; |
| 90 | |
| 91 | if (info->helper[0]) { |
| 92 | proto = xt_ct_find_proto(par); |
| 93 | if (!proto) |
| 94 | goto err3; |
| 95 | |
| 96 | help = nf_ct_helper_ext_add(ct, GFP_KERNEL); |
| 97 | if (help == NULL) |
| 98 | goto err3; |
| 99 | |
| 100 | help->helper = nf_conntrack_helper_try_module_get(info->helper, |
| 101 | par->family, |
| 102 | proto); |
| 103 | if (help->helper == NULL) |
| 104 | goto err3; |
| 105 | } |
| 106 | |
| 107 | __set_bit(IPS_TEMPLATE_BIT, &ct->status); |
| 108 | __set_bit(IPS_CONFIRMED_BIT, &ct->status); |
| 109 | out: |
| 110 | info->ct = ct; |
| 111 | return true; |
| 112 | |
| 113 | err3: |
| 114 | nf_conntrack_free(ct); |
| 115 | err2: |
| 116 | nf_ct_l3proto_module_put(par->family); |
| 117 | err1: |
| 118 | return false; |
| 119 | } |
| 120 | |
| 121 | static void xt_ct_tg_destroy(const struct xt_tgdtor_param *par) |
| 122 | { |
| 123 | struct xt_ct_target_info *info = par->targinfo; |
| 124 | struct nf_conn *ct = info->ct; |
| 125 | struct nf_conn_help *help; |
| 126 | |
| 127 | if (ct != &nf_conntrack_untracked) { |
| 128 | help = nfct_help(ct); |
| 129 | if (help) |
| 130 | module_put(help->helper->me); |
| 131 | |
| 132 | nf_ct_l3proto_module_put(par->family); |
| 133 | } |
| 134 | nf_ct_put(info->ct); |
| 135 | } |
| 136 | |
| 137 | static struct xt_target xt_ct_tg __read_mostly = { |
| 138 | .name = "CT", |
| 139 | .family = NFPROTO_UNSPEC, |
| 140 | .targetsize = XT_ALIGN(sizeof(struct xt_ct_target_info)), |
| 141 | .checkentry = xt_ct_tg_check, |
| 142 | .destroy = xt_ct_tg_destroy, |
| 143 | .target = xt_ct_target, |
| 144 | .table = "raw", |
| 145 | .me = THIS_MODULE, |
| 146 | }; |
| 147 | |
| 148 | static int __init xt_ct_tg_init(void) |
| 149 | { |
| 150 | return xt_register_target(&xt_ct_tg); |
| 151 | } |
| 152 | |
| 153 | static void __exit xt_ct_tg_exit(void) |
| 154 | { |
| 155 | xt_unregister_target(&xt_ct_tg); |
| 156 | } |
| 157 | |
| 158 | module_init(xt_ct_tg_init); |
| 159 | module_exit(xt_ct_tg_exit); |
| 160 | |
| 161 | MODULE_LICENSE("GPL"); |
| 162 | MODULE_DESCRIPTION("Xtables: connection tracking target"); |
| 163 | MODULE_ALIAS("ipt_CT"); |
| 164 | MODULE_ALIAS("ip6t_CT"); |