1 /* 2 * xt_connmark - Netfilter module to operate on connection marks 3 * 4 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com> 5 * by Henrik Nordstrom <hno@marasystems.com> 6 * Copyright © CC Computer Consultants GmbH, 2007 - 2008 7 * Jan Engelhardt <jengelh@medozas.de> 8 * 9 * This program is free software; you can redistribute it and/or modify 10 * it under the terms of the GNU General Public License as published by 11 * the Free Software Foundation; either version 2 of the License, or 12 * (at your option) any later version. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, see <http://www.gnu.org/licenses/>. 21 */ 22 23 #include <linux/module.h> 24 #include <linux/skbuff.h> 25 #include <net/netfilter/nf_conntrack.h> 26 #include <net/netfilter/nf_conntrack_ecache.h> 27 #include <linux/netfilter/x_tables.h> 28 #include <linux/netfilter/xt_connmark.h> 29 30 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); 31 MODULE_DESCRIPTION("Xtables: connection mark operations"); 32 MODULE_LICENSE("GPL"); 33 MODULE_ALIAS("ipt_CONNMARK"); 34 MODULE_ALIAS("ip6t_CONNMARK"); 35 MODULE_ALIAS("ipt_connmark"); 36 MODULE_ALIAS("ip6t_connmark"); 37 38 static unsigned int 39 connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 40 { 41 const struct xt_connmark_tginfo1 *info = par->targinfo; 42 enum ip_conntrack_info ctinfo; 43 struct nf_conn *ct; 44 u_int32_t newmark; 45 46 ct = nf_ct_get(skb, &ctinfo); 47 if (ct == NULL || nf_ct_is_untracked(ct)) 48 return XT_CONTINUE; 49 50 switch (info->mode) { 51 case XT_CONNMARK_SET: 52 newmark = (ct->mark & ~info->ctmask) ^ info->ctmark; 53 if (ct->mark != newmark) { 54 ct->mark = newmark; 55 nf_conntrack_event_cache(IPCT_MARK, ct); 56 } 57 break; 58 case XT_CONNMARK_SAVE: 59 newmark = (ct->mark & ~info->ctmask) ^ 60 (skb->mark & info->nfmask); 61 if (ct->mark != newmark) { 62 ct->mark = newmark; 63 nf_conntrack_event_cache(IPCT_MARK, ct); 64 } 65 break; 66 case XT_CONNMARK_RESTORE: 67 newmark = (skb->mark & ~info->nfmask) ^ 68 (ct->mark & info->ctmask); 69 skb->mark = newmark; 70 break; 71 } 72 73 return XT_CONTINUE; 74 } 75 76 static int connmark_tg_check(const struct xt_tgchk_param *par) 77 { 78 int ret; 79 80 ret = nf_ct_netns_get(par->net, par->family); 81 if (ret < 0) 82 pr_info("cannot load conntrack support for proto=%u\n", 83 par->family); 84 return ret; 85 } 86 87 static void connmark_tg_destroy(const struct xt_tgdtor_param *par) 88 { 89 nf_ct_netns_put(par->net, par->family); 90 } 91 92 static bool 93 connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) 94 { 95 const struct xt_connmark_mtinfo1 *info = par->matchinfo; 96 enum ip_conntrack_info ctinfo; 97 const struct nf_conn *ct; 98 99 ct = nf_ct_get(skb, &ctinfo); 100 if (ct == NULL || nf_ct_is_untracked(ct)) 101 return false; 102 103 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 104 } 105 106 static int connmark_mt_check(const struct xt_mtchk_param *par) 107 { 108 int ret; 109 110 ret = nf_ct_netns_get(par->net, par->family); 111 if (ret < 0) 112 pr_info("cannot load conntrack support for proto=%u\n", 113 par->family); 114 return ret; 115 } 116 117 static void connmark_mt_destroy(const struct xt_mtdtor_param *par) 118 { 119 nf_ct_netns_put(par->net, par->family); 120 } 121 122 static struct xt_target connmark_tg_reg __read_mostly = { 123 .name = "CONNMARK", 124 .revision = 1, 125 .family = NFPROTO_UNSPEC, 126 .checkentry = connmark_tg_check, 127 .target = connmark_tg, 128 .targetsize = sizeof(struct xt_connmark_tginfo1), 129 .destroy = connmark_tg_destroy, 130 .me = THIS_MODULE, 131 }; 132 133 static struct xt_match connmark_mt_reg __read_mostly = { 134 .name = "connmark", 135 .revision = 1, 136 .family = NFPROTO_UNSPEC, 137 .checkentry = connmark_mt_check, 138 .match = connmark_mt, 139 .matchsize = sizeof(struct xt_connmark_mtinfo1), 140 .destroy = connmark_mt_destroy, 141 .me = THIS_MODULE, 142 }; 143 144 static int __init connmark_mt_init(void) 145 { 146 int ret; 147 148 ret = xt_register_target(&connmark_tg_reg); 149 if (ret < 0) 150 return ret; 151 ret = xt_register_match(&connmark_mt_reg); 152 if (ret < 0) { 153 xt_unregister_target(&connmark_tg_reg); 154 return ret; 155 } 156 return 0; 157 } 158 159 static void __exit connmark_mt_exit(void) 160 { 161 xt_unregister_match(&connmark_mt_reg); 162 xt_unregister_target(&connmark_tg_reg); 163 } 164 165 module_init(connmark_mt_init); 166 module_exit(connmark_mt_exit); 167