1 /* This kernel module matches connection mark values set by the 2 * CONNMARK target 3 * 4 * Copyright (C) 2002,2004 MARA Systems AB <http://www.marasystems.com> 5 * by Henrik Nordstrom <hno@marasystems.com> 6 * 7 * This program is free software; you can redistribute it and/or modify 8 * it under the terms of the GNU General Public License as published by 9 * the Free Software Foundation; either version 2 of the License, or 10 * (at your option) any later version. 11 * 12 * This program is distributed in the hope that it will be useful, 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 15 * GNU General Public License for more details. 16 * 17 * You should have received a copy of the GNU General Public License 18 * along with this program; if not, write to the Free Software 19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 20 */ 21 22 #include <linux/module.h> 23 #include <linux/skbuff.h> 24 #include <net/netfilter/nf_conntrack.h> 25 #include <linux/netfilter/x_tables.h> 26 #include <linux/netfilter/xt_connmark.h> 27 28 MODULE_AUTHOR("Henrik Nordstrom <hno@marasystems.com>"); 29 MODULE_DESCRIPTION("IP tables connmark match module"); 30 MODULE_LICENSE("GPL"); 31 MODULE_ALIAS("ipt_connmark"); 32 MODULE_ALIAS("ip6t_connmark"); 33 34 static bool 35 connmark_mt(const struct sk_buff *skb, const struct net_device *in, 36 const struct net_device *out, const struct xt_match *match, 37 const void *matchinfo, int offset, unsigned int protoff, 38 bool *hotdrop) 39 { 40 const struct xt_connmark_info *info = matchinfo; 41 const struct nf_conn *ct; 42 enum ip_conntrack_info ctinfo; 43 44 ct = nf_ct_get(skb, &ctinfo); 45 if (!ct) 46 return false; 47 48 return ((ct->mark & info->mask) == info->mark) ^ info->invert; 49 } 50 51 static bool 52 connmark_mt_check(const char *tablename, const void *ip, 53 const struct xt_match *match, void *matchinfo, 54 unsigned int hook_mask) 55 { 56 const struct xt_connmark_info *cm = matchinfo; 57 58 if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) { 59 printk(KERN_WARNING "connmark: only support 32bit mark\n"); 60 return false; 61 } 62 if (nf_ct_l3proto_try_module_get(match->family) < 0) { 63 printk(KERN_WARNING "can't load conntrack support for " 64 "proto=%d\n", match->family); 65 return false; 66 } 67 return true; 68 } 69 70 static void 71 connmark_mt_destroy(const struct xt_match *match, void *matchinfo) 72 { 73 nf_ct_l3proto_module_put(match->family); 74 } 75 76 #ifdef CONFIG_COMPAT 77 struct compat_xt_connmark_info { 78 compat_ulong_t mark, mask; 79 u_int8_t invert; 80 u_int8_t __pad1; 81 u_int16_t __pad2; 82 }; 83 84 static void connmark_mt_compat_from_user(void *dst, void *src) 85 { 86 const struct compat_xt_connmark_info *cm = src; 87 struct xt_connmark_info m = { 88 .mark = cm->mark, 89 .mask = cm->mask, 90 .invert = cm->invert, 91 }; 92 memcpy(dst, &m, sizeof(m)); 93 } 94 95 static int connmark_mt_compat_to_user(void __user *dst, void *src) 96 { 97 const struct xt_connmark_info *m = src; 98 struct compat_xt_connmark_info cm = { 99 .mark = m->mark, 100 .mask = m->mask, 101 .invert = m->invert, 102 }; 103 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; 104 } 105 #endif /* CONFIG_COMPAT */ 106 107 static struct xt_match connmark_mt_reg[] __read_mostly = { 108 { 109 .name = "connmark", 110 .family = AF_INET, 111 .checkentry = connmark_mt_check, 112 .match = connmark_mt, 113 .destroy = connmark_mt_destroy, 114 .matchsize = sizeof(struct xt_connmark_info), 115 #ifdef CONFIG_COMPAT 116 .compatsize = sizeof(struct compat_xt_connmark_info), 117 .compat_from_user = connmark_mt_compat_from_user, 118 .compat_to_user = connmark_mt_compat_to_user, 119 #endif 120 .me = THIS_MODULE 121 }, 122 { 123 .name = "connmark", 124 .family = AF_INET6, 125 .checkentry = connmark_mt_check, 126 .match = connmark_mt, 127 .destroy = connmark_mt_destroy, 128 .matchsize = sizeof(struct xt_connmark_info), 129 #ifdef CONFIG_COMPAT 130 .compatsize = sizeof(struct compat_xt_connmark_info), 131 .compat_from_user = connmark_mt_compat_from_user, 132 .compat_to_user = connmark_mt_compat_to_user, 133 #endif 134 .me = THIS_MODULE 135 }, 136 }; 137 138 static int __init connmark_mt_init(void) 139 { 140 return xt_register_matches(connmark_mt_reg, 141 ARRAY_SIZE(connmark_mt_reg)); 142 } 143 144 static void __exit connmark_mt_exit(void) 145 { 146 xt_unregister_matches(connmark_mt_reg, ARRAY_SIZE(connmark_mt_reg)); 147 } 148 149 module_init(connmark_mt_init); 150 module_exit(connmark_mt_exit); 151