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, write to the Free Software 21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 22 */ 23 24 #include <linux/module.h> 25 #include <linux/skbuff.h> 26 #include <net/netfilter/nf_conntrack.h> 27 #include <net/netfilter/nf_conntrack_ecache.h> 28 #include <linux/netfilter/x_tables.h> 29 #include <linux/netfilter/xt_connmark.h> 30 31 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); 32 MODULE_DESCRIPTION("Xtables: connection mark operations"); 33 MODULE_LICENSE("GPL"); 34 MODULE_ALIAS("ipt_CONNMARK"); 35 MODULE_ALIAS("ip6t_CONNMARK"); 36 MODULE_ALIAS("ipt_connmark"); 37 MODULE_ALIAS("ip6t_connmark"); 38 39 static unsigned int 40 connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 41 { 42 const struct xt_connmark_tginfo1 *info = par->targinfo; 43 enum ip_conntrack_info ctinfo; 44 struct nf_conn *ct; 45 u_int32_t newmark; 46 47 ct = nf_ct_get(skb, &ctinfo); 48 if (ct == NULL) 49 return XT_CONTINUE; 50 51 switch (info->mode) { 52 case XT_CONNMARK_SET: 53 newmark = (ct->mark & ~info->ctmask) ^ info->ctmark; 54 if (ct->mark != newmark) { 55 ct->mark = newmark; 56 nf_conntrack_event_cache(IPCT_MARK, ct); 57 } 58 break; 59 case XT_CONNMARK_SAVE: 60 newmark = (ct->mark & ~info->ctmask) ^ 61 (skb->mark & info->nfmask); 62 if (ct->mark != newmark) { 63 ct->mark = newmark; 64 nf_conntrack_event_cache(IPCT_MARK, ct); 65 } 66 break; 67 case XT_CONNMARK_RESTORE: 68 newmark = (skb->mark & ~info->nfmask) ^ 69 (ct->mark & info->ctmask); 70 skb->mark = newmark; 71 break; 72 } 73 74 return XT_CONTINUE; 75 } 76 77 static int connmark_tg_check(const struct xt_tgchk_param *par) 78 { 79 int ret; 80 81 ret = nf_ct_l3proto_try_module_get(par->family); 82 if (ret < 0) 83 pr_info("cannot load conntrack support for proto=%u\n", 84 par->family); 85 return ret; 86 } 87 88 static void connmark_tg_destroy(const struct xt_tgdtor_param *par) 89 { 90 nf_ct_l3proto_module_put(par->family); 91 } 92 93 static bool 94 connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) 95 { 96 const struct xt_connmark_mtinfo1 *info = par->matchinfo; 97 enum ip_conntrack_info ctinfo; 98 const struct nf_conn *ct; 99 100 ct = nf_ct_get(skb, &ctinfo); 101 if (ct == NULL) 102 return false; 103 104 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 105 } 106 107 static int connmark_mt_check(const struct xt_mtchk_param *par) 108 { 109 int ret; 110 111 ret = nf_ct_l3proto_try_module_get(par->family); 112 if (ret < 0) 113 pr_info("cannot load conntrack support for proto=%u\n", 114 par->family); 115 return ret; 116 } 117 118 static void connmark_mt_destroy(const struct xt_mtdtor_param *par) 119 { 120 nf_ct_l3proto_module_put(par->family); 121 } 122 123 static struct xt_target connmark_tg_reg __read_mostly = { 124 .name = "CONNMARK", 125 .revision = 1, 126 .family = NFPROTO_UNSPEC, 127 .checkentry = connmark_tg_check, 128 .target = connmark_tg, 129 .targetsize = sizeof(struct xt_connmark_tginfo1), 130 .destroy = connmark_tg_destroy, 131 .me = THIS_MODULE, 132 }; 133 134 static struct xt_match connmark_mt_reg __read_mostly = { 135 .name = "connmark", 136 .revision = 1, 137 .family = NFPROTO_UNSPEC, 138 .checkentry = connmark_mt_check, 139 .match = connmark_mt, 140 .matchsize = sizeof(struct xt_connmark_mtinfo1), 141 .destroy = connmark_mt_destroy, 142 .me = THIS_MODULE, 143 }; 144 145 static int __init connmark_mt_init(void) 146 { 147 int ret; 148 149 ret = xt_register_target(&connmark_tg_reg); 150 if (ret < 0) 151 return ret; 152 ret = xt_register_match(&connmark_mt_reg); 153 if (ret < 0) { 154 xt_unregister_target(&connmark_tg_reg); 155 return ret; 156 } 157 return 0; 158 } 159 160 static void __exit connmark_mt_exit(void) 161 { 162 xt_unregister_match(&connmark_mt_reg); 163 xt_unregister_target(&connmark_tg_reg); 164 } 165 166 module_init(connmark_mt_init); 167 module_exit(connmark_mt_exit); 168