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_shift(struct sk_buff *skb, const struct xt_connmark_tginfo2 *info) 40 { 41 enum ip_conntrack_info ctinfo; 42 u_int32_t new_targetmark; 43 struct nf_conn *ct; 44 u_int32_t newmark; 45 46 ct = nf_ct_get(skb, &ctinfo); 47 if (ct == NULL) 48 return XT_CONTINUE; 49 50 switch (info->mode) { 51 case XT_CONNMARK_SET: 52 newmark = (ct->mark & ~info->ctmask) ^ info->ctmark; 53 if (info->shift_dir == D_SHIFT_RIGHT) 54 newmark >>= info->shift_bits; 55 else 56 newmark <<= info->shift_bits; 57 58 if (ct->mark != newmark) { 59 ct->mark = newmark; 60 nf_conntrack_event_cache(IPCT_MARK, ct); 61 } 62 break; 63 case XT_CONNMARK_SAVE: 64 new_targetmark = (skb->mark & info->nfmask); 65 if (info->shift_dir == D_SHIFT_RIGHT) 66 new_targetmark >>= info->shift_bits; 67 else 68 new_targetmark <<= info->shift_bits; 69 70 newmark = (ct->mark & ~info->ctmask) ^ 71 new_targetmark; 72 if (ct->mark != newmark) { 73 ct->mark = newmark; 74 nf_conntrack_event_cache(IPCT_MARK, ct); 75 } 76 break; 77 case XT_CONNMARK_RESTORE: 78 new_targetmark = (ct->mark & info->ctmask); 79 if (info->shift_dir == D_SHIFT_RIGHT) 80 new_targetmark >>= info->shift_bits; 81 else 82 new_targetmark <<= info->shift_bits; 83 84 newmark = (skb->mark & ~info->nfmask) ^ 85 new_targetmark; 86 skb->mark = newmark; 87 break; 88 } 89 return XT_CONTINUE; 90 } 91 92 static unsigned int 93 connmark_tg(struct sk_buff *skb, const struct xt_action_param *par) 94 { 95 const struct xt_connmark_tginfo1 *info = par->targinfo; 96 const struct xt_connmark_tginfo2 info2 = { 97 .ctmark = info->ctmark, 98 .ctmask = info->ctmask, 99 .nfmask = info->nfmask, 100 .mode = info->mode, 101 }; 102 103 return connmark_tg_shift(skb, &info2); 104 } 105 106 static unsigned int 107 connmark_tg_v2(struct sk_buff *skb, const struct xt_action_param *par) 108 { 109 const struct xt_connmark_tginfo2 *info = par->targinfo; 110 111 return connmark_tg_shift(skb, info); 112 } 113 114 static int connmark_tg_check(const struct xt_tgchk_param *par) 115 { 116 int ret; 117 118 ret = nf_ct_netns_get(par->net, par->family); 119 if (ret < 0) 120 pr_info_ratelimited("cannot load conntrack support for proto=%u\n", 121 par->family); 122 return ret; 123 } 124 125 static void connmark_tg_destroy(const struct xt_tgdtor_param *par) 126 { 127 nf_ct_netns_put(par->net, par->family); 128 } 129 130 static bool 131 connmark_mt(const struct sk_buff *skb, struct xt_action_param *par) 132 { 133 const struct xt_connmark_mtinfo1 *info = par->matchinfo; 134 enum ip_conntrack_info ctinfo; 135 const struct nf_conn *ct; 136 137 ct = nf_ct_get(skb, &ctinfo); 138 if (ct == NULL) 139 return false; 140 141 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 142 } 143 144 static int connmark_mt_check(const struct xt_mtchk_param *par) 145 { 146 int ret; 147 148 ret = nf_ct_netns_get(par->net, par->family); 149 if (ret < 0) 150 pr_info_ratelimited("cannot load conntrack support for proto=%u\n", 151 par->family); 152 return ret; 153 } 154 155 static void connmark_mt_destroy(const struct xt_mtdtor_param *par) 156 { 157 nf_ct_netns_put(par->net, par->family); 158 } 159 160 static struct xt_target connmark_tg_reg[] __read_mostly = { 161 { 162 .name = "CONNMARK", 163 .revision = 1, 164 .family = NFPROTO_UNSPEC, 165 .checkentry = connmark_tg_check, 166 .target = connmark_tg, 167 .targetsize = sizeof(struct xt_connmark_tginfo1), 168 .destroy = connmark_tg_destroy, 169 .me = THIS_MODULE, 170 }, 171 { 172 .name = "CONNMARK", 173 .revision = 2, 174 .family = NFPROTO_UNSPEC, 175 .checkentry = connmark_tg_check, 176 .target = connmark_tg_v2, 177 .targetsize = sizeof(struct xt_connmark_tginfo2), 178 .destroy = connmark_tg_destroy, 179 .me = THIS_MODULE, 180 } 181 }; 182 183 static struct xt_match connmark_mt_reg __read_mostly = { 184 .name = "connmark", 185 .revision = 1, 186 .family = NFPROTO_UNSPEC, 187 .checkentry = connmark_mt_check, 188 .match = connmark_mt, 189 .matchsize = sizeof(struct xt_connmark_mtinfo1), 190 .destroy = connmark_mt_destroy, 191 .me = THIS_MODULE, 192 }; 193 194 static int __init connmark_mt_init(void) 195 { 196 int ret; 197 198 ret = xt_register_targets(connmark_tg_reg, 199 ARRAY_SIZE(connmark_tg_reg)); 200 if (ret < 0) 201 return ret; 202 ret = xt_register_match(&connmark_mt_reg); 203 if (ret < 0) { 204 xt_unregister_targets(connmark_tg_reg, 205 ARRAY_SIZE(connmark_tg_reg)); 206 return ret; 207 } 208 return 0; 209 } 210 211 static void __exit connmark_mt_exit(void) 212 { 213 xt_unregister_match(&connmark_mt_reg); 214 xt_unregister_targets(connmark_tg_reg, ARRAY_SIZE(connmark_tg_reg)); 215 } 216 217 module_init(connmark_mt_init); 218 module_exit(connmark_mt_exit); 219