1/* This kernel module is used to modify the connection mark values, or 2 * to optionally restore the skb nfmark from the connection mark 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#include <linux/module.h> 22#include <linux/skbuff.h> 23#include <linux/ip.h> 24#include <net/checksum.h> 25 26MODULE_AUTHOR("Henrik Nordstrom <hno@marasytems.com>"); 27MODULE_DESCRIPTION("IP tables CONNMARK matching module"); 28MODULE_LICENSE("GPL"); 29MODULE_ALIAS("ipt_CONNMARK"); 30 31#include <linux/netfilter/x_tables.h> 32#include <linux/netfilter/xt_CONNMARK.h> 33#include <net/netfilter/nf_conntrack_ecache.h> 34 35static unsigned int 36target(struct sk_buff **pskb, 37 const struct net_device *in, 38 const struct net_device *out, 39 unsigned int hooknum, 40 const struct xt_target *target, 41 const void *targinfo) 42{ 43 const struct xt_connmark_target_info *markinfo = targinfo; 44 struct nf_conn *ct; 45 enum ip_conntrack_info ctinfo; 46 u_int32_t diff; 47 u_int32_t mark; 48 u_int32_t newmark; 49 50 ct = nf_ct_get(*pskb, &ctinfo); 51 if (ct) { 52 switch(markinfo->mode) { 53 case XT_CONNMARK_SET: 54 newmark = (ct->mark & ~markinfo->mask) | markinfo->mark; 55 if (newmark != ct->mark) { 56 ct->mark = newmark; 57 nf_conntrack_event_cache(IPCT_MARK, *pskb); 58 } 59 break; 60 case XT_CONNMARK_SAVE: 61 newmark = (ct->mark & ~markinfo->mask) | 62 ((*pskb)->mark & markinfo->mask); 63 if (ct->mark != newmark) { 64 ct->mark = newmark; 65 nf_conntrack_event_cache(IPCT_MARK, *pskb); 66 } 67 break; 68 case XT_CONNMARK_RESTORE: 69 mark = (*pskb)->mark; 70 diff = (ct->mark ^ mark) & markinfo->mask; 71 (*pskb)->mark = mark ^ diff; 72 break; 73 } 74 } 75 76 return XT_CONTINUE; 77} 78 79static int 80checkentry(const char *tablename, 81 const void *entry, 82 const struct xt_target *target, 83 void *targinfo, 84 unsigned int hook_mask) 85{ 86 struct xt_connmark_target_info *matchinfo = targinfo; 87 88 if (nf_ct_l3proto_try_module_get(target->family) < 0) { 89 printk(KERN_WARNING "can't load conntrack support for " 90 "proto=%d\n", target->family); 91 return 0; 92 } 93 if (matchinfo->mode == XT_CONNMARK_RESTORE) { 94 if (strcmp(tablename, "mangle") != 0) { 95 printk(KERN_WARNING "CONNMARK: restore can only be " 96 "called from \"mangle\" table, not \"%s\"\n", 97 tablename); 98 return 0; 99 } 100 } 101 if (matchinfo->mark > 0xffffffff || matchinfo->mask > 0xffffffff) { 102 printk(KERN_WARNING "CONNMARK: Only supports 32bit mark\n"); 103 return 0; 104 } 105 return 1; 106} 107 108static void 109destroy(const struct xt_target *target, void *targinfo) 110{ 111 nf_ct_l3proto_module_put(target->family); 112} 113 114#ifdef CONFIG_COMPAT 115struct compat_xt_connmark_target_info { 116 compat_ulong_t mark, mask; 117 u_int8_t mode; 118 u_int8_t __pad1; 119 u_int16_t __pad2; 120}; 121 122static void compat_from_user(void *dst, void *src) 123{ 124 struct compat_xt_connmark_target_info *cm = src; 125 struct xt_connmark_target_info m = { 126 .mark = cm->mark, 127 .mask = cm->mask, 128 .mode = cm->mode, 129 }; 130 memcpy(dst, &m, sizeof(m)); 131} 132 133static int compat_to_user(void __user *dst, void *src) 134{ 135 struct xt_connmark_target_info *m = src; 136 struct compat_xt_connmark_target_info cm = { 137 .mark = m->mark, 138 .mask = m->mask, 139 .mode = m->mode, 140 }; 141 return copy_to_user(dst, &cm, sizeof(cm)) ? -EFAULT : 0; 142} 143#endif /* CONFIG_COMPAT */ 144 145static struct xt_target xt_connmark_target[] = { 146 { 147 .name = "CONNMARK", 148 .family = AF_INET, 149 .checkentry = checkentry, 150 .destroy = destroy, 151 .target = target, 152 .targetsize = sizeof(struct xt_connmark_target_info), 153#ifdef CONFIG_COMPAT 154 .compatsize = sizeof(struct compat_xt_connmark_target_info), 155 .compat_from_user = compat_from_user, 156 .compat_to_user = compat_to_user, 157#endif 158 .me = THIS_MODULE 159 }, 160 { 161 .name = "CONNMARK", 162 .family = AF_INET6, 163 .checkentry = checkentry, 164 .destroy = destroy, 165 .target = target, 166 .targetsize = sizeof(struct xt_connmark_target_info), 167 .me = THIS_MODULE 168 }, 169}; 170 171static int __init xt_connmark_init(void) 172{ 173 return xt_register_targets(xt_connmark_target, 174 ARRAY_SIZE(xt_connmark_target)); 175} 176 177static void __exit xt_connmark_fini(void) 178{ 179 xt_unregister_targets(xt_connmark_target, 180 ARRAY_SIZE(xt_connmark_target)); 181} 182 183module_init(xt_connmark_init); 184module_exit(xt_connmark_fini); 185