xt_state.c revision 5d04bff096180f032de8b9b12153a8a1b4009b8d
1/* Kernel module to match connection tracking information. */ 2 3/* (C) 1999-2001 Paul `Rusty' Russell 4 * (C) 2002-2005 Netfilter Core Team <coreteam@netfilter.org> 5 * 6 * This program is free software; you can redistribute it and/or modify 7 * it under the terms of the GNU General Public License version 2 as 8 * published by the Free Software Foundation. 9 */ 10 11#include <linux/module.h> 12#include <linux/skbuff.h> 13#include <net/netfilter/nf_conntrack_compat.h> 14#include <linux/netfilter/x_tables.h> 15#include <linux/netfilter/xt_state.h> 16 17MODULE_LICENSE("GPL"); 18MODULE_AUTHOR("Rusty Russell <rusty@rustcorp.com.au>"); 19MODULE_DESCRIPTION("ip[6]_tables connection tracking state match module"); 20MODULE_ALIAS("ipt_state"); 21MODULE_ALIAS("ip6t_state"); 22 23static int 24match(const struct sk_buff *skb, 25 const struct net_device *in, 26 const struct net_device *out, 27 const void *matchinfo, 28 int offset, 29 unsigned int protoff, 30 int *hotdrop) 31{ 32 const struct xt_state_info *sinfo = matchinfo; 33 enum ip_conntrack_info ctinfo; 34 unsigned int statebit; 35 36 if (nf_ct_is_untracked(skb)) 37 statebit = XT_STATE_UNTRACKED; 38 else if (!nf_ct_get_ctinfo(skb, &ctinfo)) 39 statebit = XT_STATE_INVALID; 40 else 41 statebit = XT_STATE_BIT(ctinfo); 42 43 return (sinfo->statemask & statebit); 44} 45 46static struct xt_match state_match = { 47 .name = "state", 48 .match = match, 49 .matchsize = sizeof(struct xt_state_info), 50 .me = THIS_MODULE, 51}; 52 53static struct xt_match state6_match = { 54 .name = "state", 55 .match = match, 56 .matchsize = sizeof(struct xt_state_info), 57 .me = THIS_MODULE, 58}; 59 60static int __init init(void) 61{ 62 int ret; 63 64 need_conntrack(); 65 66 ret = xt_register_match(AF_INET, &state_match); 67 if (ret < 0) 68 return ret; 69 70 ret = xt_register_match(AF_INET6, &state6_match); 71 if (ret < 0) 72 xt_unregister_match(AF_INET,&state_match); 73 74 return ret; 75} 76 77static void __exit fini(void) 78{ 79 xt_unregister_match(AF_INET, &state_match); 80 xt_unregister_match(AF_INET6, &state6_match); 81} 82 83module_init(init); 84module_exit(fini); 85