1 /* 2 * xt_connmark - Netfilter module to match connection mark values 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@computergmbh.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 <linux/netfilter/x_tables.h> 28 #include <linux/netfilter/xt_connmark.h> 29 30 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); 31 MODULE_DESCRIPTION("IP tables connmark match module"); 32 MODULE_LICENSE("GPL"); 33 MODULE_ALIAS("ipt_connmark"); 34 MODULE_ALIAS("ip6t_connmark"); 35 36 static bool 37 connmark_mt(const struct sk_buff *skb, const struct net_device *in, 38 const struct net_device *out, const struct xt_match *match, 39 const void *matchinfo, int offset, unsigned int protoff, 40 bool *hotdrop) 41 { 42 const struct xt_connmark_mtinfo1 *info = matchinfo; 43 enum ip_conntrack_info ctinfo; 44 const struct nf_conn *ct; 45 46 ct = nf_ct_get(skb, &ctinfo); 47 if (ct == NULL) 48 return false; 49 50 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 51 } 52 53 static bool 54 connmark_mt_v0(const struct sk_buff *skb, const struct net_device *in, 55 const struct net_device *out, const struct xt_match *match, 56 const void *matchinfo, int offset, unsigned int protoff, 57 bool *hotdrop) 58 { 59 const struct xt_connmark_info *info = matchinfo; 60 const struct nf_conn *ct; 61 enum ip_conntrack_info ctinfo; 62 63 ct = nf_ct_get(skb, &ctinfo); 64 if (!ct) 65 return false; 66 67 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 68 } 69 70 static bool 71 connmark_mt_check_v0(const char *tablename, const void *ip, 72 const struct xt_match *match, void *matchinfo, 73 unsigned int hook_mask) 74 { 75 const struct xt_connmark_info *cm = matchinfo; 76 77 if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) { 78 printk(KERN_WARNING "connmark: only support 32bit mark\n"); 79 return false; 80 } 81 if (nf_ct_l3proto_try_module_get(match->family) < 0) { 82 printk(KERN_WARNING "can't load conntrack support for " 83 "proto=%u\n", match->family); 84 return false; 85 } 86 return true; 87 } 88 89 static bool 90 connmark_mt_check(const char *tablename, const void *ip, 91 const struct xt_match *match, void *matchinfo, 92 unsigned int hook_mask) 93 { 94 if (nf_ct_l3proto_try_module_get(match->family) < 0) { 95 printk(KERN_WARNING "cannot load conntrack support for " 96 "proto=%u\n", match->family); 97 return false; 98 } 99 return true; 100 } 101 102 static void 103 connmark_mt_destroy(const struct xt_match *match, void *matchinfo) 104 { 105 nf_ct_l3proto_module_put(match->family); 106 } 107 108 #ifdef CONFIG_COMPAT 109 struct compat_xt_connmark_info { 110 compat_ulong_t mark, mask; 111 u_int8_t invert; 112 u_int8_t __pad1; 113 u_int16_t __pad2; 114 }; 115 116 static void connmark_mt_compat_from_user_v0(void *dst, void *src) 117 { 118 const struct compat_xt_connmark_info *cm = src; 119 struct xt_connmark_info m = { 120 .mark = cm->mark, 121 .mask = cm->mask, 122 .invert = cm->invert, 123 }; 124 memcpy(dst, &m, sizeof(m)); 125 } 126 127 static int connmark_mt_compat_to_user_v0(void __user *dst, void *src) 128 { 129 const struct xt_connmark_info *m = src; 130 struct compat_xt_connmark_info cm = { 131 .mark = m->mark, 132 .mask = m->mask, 133 .invert = m->invert, 134 }; 135 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; 136 } 137 #endif /* CONFIG_COMPAT */ 138 139 static struct xt_match connmark_mt_reg[] __read_mostly = { 140 { 141 .name = "connmark", 142 .revision = 0, 143 .family = AF_INET, 144 .checkentry = connmark_mt_check_v0, 145 .match = connmark_mt_v0, 146 .destroy = connmark_mt_destroy, 147 .matchsize = sizeof(struct xt_connmark_info), 148 #ifdef CONFIG_COMPAT 149 .compatsize = sizeof(struct compat_xt_connmark_info), 150 .compat_from_user = connmark_mt_compat_from_user_v0, 151 .compat_to_user = connmark_mt_compat_to_user_v0, 152 #endif 153 .me = THIS_MODULE 154 }, 155 { 156 .name = "connmark", 157 .revision = 0, 158 .family = AF_INET6, 159 .checkentry = connmark_mt_check_v0, 160 .match = connmark_mt_v0, 161 .destroy = connmark_mt_destroy, 162 .matchsize = sizeof(struct xt_connmark_info), 163 #ifdef CONFIG_COMPAT 164 .compatsize = sizeof(struct compat_xt_connmark_info), 165 .compat_from_user = connmark_mt_compat_from_user_v0, 166 .compat_to_user = connmark_mt_compat_to_user_v0, 167 #endif 168 .me = THIS_MODULE 169 }, 170 { 171 .name = "connmark", 172 .revision = 1, 173 .family = AF_INET, 174 .checkentry = connmark_mt_check, 175 .match = connmark_mt, 176 .matchsize = sizeof(struct xt_connmark_mtinfo1), 177 .destroy = connmark_mt_destroy, 178 .me = THIS_MODULE, 179 }, 180 { 181 .name = "connmark", 182 .revision = 1, 183 .family = AF_INET6, 184 .checkentry = connmark_mt_check, 185 .match = connmark_mt, 186 .matchsize = sizeof(struct xt_connmark_mtinfo1), 187 .destroy = connmark_mt_destroy, 188 .me = THIS_MODULE, 189 }, 190 }; 191 192 static int __init connmark_mt_init(void) 193 { 194 return xt_register_matches(connmark_mt_reg, 195 ARRAY_SIZE(connmark_mt_reg)); 196 } 197 198 static void __exit connmark_mt_exit(void) 199 { 200 xt_unregister_matches(connmark_mt_reg, ARRAY_SIZE(connmark_mt_reg)); 201 } 202 203 module_init(connmark_mt_init); 204 module_exit(connmark_mt_exit); 205