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 25 MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>"); 26 MODULE_DESCRIPTION("IP tables connmark match module"); 27 MODULE_LICENSE("GPL"); 28 MODULE_ALIAS("ipt_connmark"); 29 30 #include <linux/netfilter/x_tables.h> 31 #include <linux/netfilter/xt_connmark.h> 32 #include <net/netfilter/nf_conntrack_compat.h> 33 34 static int 35 match(const struct sk_buff *skb, 36 const struct net_device *in, 37 const struct net_device *out, 38 const struct xt_match *match, 39 const void *matchinfo, 40 int offset, 41 unsigned int protoff, 42 int *hotdrop) 43 { 44 const struct xt_connmark_info *info = matchinfo; 45 u_int32_t ctinfo; 46 const u_int32_t *ctmark = nf_ct_get_mark(skb, &ctinfo); 47 if (!ctmark) 48 return 0; 49 50 return (((*ctmark) & info->mask) == info->mark) ^ info->invert; 51 } 52 53 static int 54 checkentry(const char *tablename, 55 const void *ip, 56 const struct xt_match *match, 57 void *matchinfo, 58 unsigned int hook_mask) 59 { 60 struct xt_connmark_info *cm = matchinfo; 61 62 if (cm->mark > 0xffffffff || cm->mask > 0xffffffff) { 63 printk(KERN_WARNING "connmark: only support 32bit mark\n"); 64 return 0; 65 } 66 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 67 if (nf_ct_l3proto_try_module_get(match->family) < 0) { 68 printk(KERN_WARNING "can't load nf_conntrack support for " 69 "proto=%d\n", match->family); 70 return 0; 71 } 72 #endif 73 return 1; 74 } 75 76 static void 77 destroy(const struct xt_match *match, void *matchinfo) 78 { 79 #if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE) 80 nf_ct_l3proto_module_put(match->family); 81 #endif 82 } 83 84 #ifdef CONFIG_COMPAT 85 struct compat_xt_connmark_info { 86 compat_ulong_t mark, mask; 87 u_int8_t invert; 88 u_int8_t __pad1; 89 u_int16_t __pad2; 90 }; 91 92 static void compat_from_user(void *dst, void *src) 93 { 94 struct compat_xt_connmark_info *cm = src; 95 struct xt_connmark_info m = { 96 .mark = cm->mark, 97 .mask = cm->mask, 98 .invert = cm->invert, 99 }; 100 memcpy(dst, &m, sizeof(m)); 101 } 102 103 static int compat_to_user(void __user *dst, void *src) 104 { 105 struct xt_connmark_info *m = src; 106 struct compat_xt_connmark_info cm = { 107 .mark = m->mark, 108 .mask = m->mask, 109 .invert = m->invert, 110 }; 111 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; 112 } 113 #endif /* CONFIG_COMPAT */ 114 115 static struct xt_match xt_connmark_match[] = { 116 { 117 .name = "connmark", 118 .family = AF_INET, 119 .checkentry = checkentry, 120 .match = match, 121 .destroy = destroy, 122 .matchsize = sizeof(struct xt_connmark_info), 123 #ifdef CONFIG_COMPAT 124 .compatsize = sizeof(struct compat_xt_connmark_info), 125 .compat_from_user = compat_from_user, 126 .compat_to_user = compat_to_user, 127 #endif 128 .me = THIS_MODULE 129 }, 130 { 131 .name = "connmark", 132 .family = AF_INET6, 133 .checkentry = checkentry, 134 .match = match, 135 .destroy = destroy, 136 .matchsize = sizeof(struct xt_connmark_info), 137 .me = THIS_MODULE 138 }, 139 }; 140 141 static int __init xt_connmark_init(void) 142 { 143 need_conntrack(); 144 return xt_register_matches(xt_connmark_match, 145 ARRAY_SIZE(xt_connmark_match)); 146 } 147 148 static void __exit xt_connmark_fini(void) 149 { 150 xt_register_matches(xt_connmark_match, ARRAY_SIZE(xt_connmark_match)); 151 } 152 153 module_init(xt_connmark_init); 154 module_exit(xt_connmark_fini); 155