397 lines
9.1 KiB
C
397 lines
9.1 KiB
C
/*
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* Copyright (c) 2010 Patrick McHardy <kaber@trash.net>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/module.h>
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#include <linux/gfp.h>
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#include <linux/skbuff.h>
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#include <linux/netfilter_ipv4/ip_tables.h>
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#include <linux/netfilter_ipv6/ip6_tables.h>
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#include <linux/netfilter/x_tables.h>
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#include <linux/netfilter/xt_CT.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_l4proto.h>
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_ecache.h>
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#include <net/netfilter/nf_conntrack_timeout.h>
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#include <net/netfilter/nf_conntrack_zones.h>
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static unsigned int xt_ct_target_v0(struct sk_buff *skb,
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const struct xt_action_param *par)
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{
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const struct xt_ct_target_info *info = par->targinfo;
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struct nf_conn *ct = info->ct;
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/* Previously seen (loopback)? Ignore. */
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if (skb->nfct != NULL)
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return XT_CONTINUE;
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atomic_inc(&ct->ct_general.use);
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skb->nfct = &ct->ct_general;
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skb->nfctinfo = IP_CT_NEW;
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return XT_CONTINUE;
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}
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static unsigned int xt_ct_target_v1(struct sk_buff *skb,
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const struct xt_action_param *par)
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{
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const struct xt_ct_target_info_v1 *info = par->targinfo;
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struct nf_conn *ct = info->ct;
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/* Previously seen (loopback)? Ignore. */
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if (skb->nfct != NULL)
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return XT_CONTINUE;
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atomic_inc(&ct->ct_general.use);
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skb->nfct = &ct->ct_general;
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skb->nfctinfo = IP_CT_NEW;
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return XT_CONTINUE;
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}
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static u8 xt_ct_find_proto(const struct xt_tgchk_param *par)
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{
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if (par->family == NFPROTO_IPV4) {
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const struct ipt_entry *e = par->entryinfo;
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if (e->ip.invflags & IPT_INV_PROTO)
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return 0;
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return e->ip.proto;
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} else if (par->family == NFPROTO_IPV6) {
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const struct ip6t_entry *e = par->entryinfo;
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if (e->ipv6.invflags & IP6T_INV_PROTO)
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return 0;
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return e->ipv6.proto;
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} else
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return 0;
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}
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static int xt_ct_tg_check_v0(const struct xt_tgchk_param *par)
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{
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struct xt_ct_target_info *info = par->targinfo;
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struct nf_conntrack_tuple t;
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struct nf_conn_help *help;
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struct nf_conn *ct;
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int ret = 0;
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u8 proto;
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if (info->flags & ~XT_CT_NOTRACK)
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return -EINVAL;
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if (info->flags & XT_CT_NOTRACK) {
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ct = nf_ct_untracked_get();
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atomic_inc(&ct->ct_general.use);
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goto out;
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}
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#ifndef CONFIG_NF_CONNTRACK_ZONES
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if (info->zone)
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goto err1;
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#endif
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ret = nf_ct_l3proto_try_module_get(par->family);
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if (ret < 0)
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goto err1;
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memset(&t, 0, sizeof(t));
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ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
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ret = PTR_ERR(ct);
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if (IS_ERR(ct))
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goto err2;
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ret = 0;
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if ((info->ct_events || info->exp_events) &&
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!nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
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GFP_KERNEL))
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goto err3;
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if (info->helper[0]) {
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ret = -ENOENT;
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proto = xt_ct_find_proto(par);
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if (!proto) {
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pr_info("You must specify a L4 protocol, "
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"and not use inversions on it.\n");
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goto err3;
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}
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ret = -ENOMEM;
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help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
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if (help == NULL)
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goto err3;
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ret = -ENOENT;
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help->helper = nf_conntrack_helper_try_module_get(info->helper,
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par->family,
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proto);
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if (help->helper == NULL) {
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pr_info("No such helper \"%s\"\n", info->helper);
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goto err3;
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}
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}
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__set_bit(IPS_TEMPLATE_BIT, &ct->status);
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__set_bit(IPS_CONFIRMED_BIT, &ct->status);
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out:
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info->ct = ct;
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return 0;
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err3:
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nf_conntrack_free(ct);
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err2:
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nf_ct_l3proto_module_put(par->family);
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err1:
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return ret;
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}
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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static void __xt_ct_tg_timeout_put(struct ctnl_timeout *timeout)
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{
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typeof(nf_ct_timeout_put_hook) timeout_put;
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timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
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if (timeout_put)
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timeout_put(timeout);
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}
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#endif
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static int xt_ct_tg_check_v1(const struct xt_tgchk_param *par)
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{
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struct xt_ct_target_info_v1 *info = par->targinfo;
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struct nf_conntrack_tuple t;
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struct nf_conn_help *help;
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struct nf_conn *ct;
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int ret = 0;
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u8 proto;
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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struct ctnl_timeout *timeout;
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#endif
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if (info->flags & ~XT_CT_NOTRACK)
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return -EINVAL;
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if (info->flags & XT_CT_NOTRACK) {
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ct = nf_ct_untracked_get();
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atomic_inc(&ct->ct_general.use);
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goto out;
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}
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#ifndef CONFIG_NF_CONNTRACK_ZONES
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if (info->zone)
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goto err1;
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#endif
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ret = nf_ct_l3proto_try_module_get(par->family);
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if (ret < 0)
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goto err1;
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memset(&t, 0, sizeof(t));
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ct = nf_conntrack_alloc(par->net, info->zone, &t, &t, GFP_KERNEL);
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ret = PTR_ERR(ct);
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if (IS_ERR(ct))
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goto err2;
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ret = 0;
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if ((info->ct_events || info->exp_events) &&
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!nf_ct_ecache_ext_add(ct, info->ct_events, info->exp_events,
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GFP_KERNEL))
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goto err3;
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if (info->helper[0]) {
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ret = -ENOENT;
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proto = xt_ct_find_proto(par);
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if (!proto) {
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pr_info("You must specify a L4 protocol, "
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"and not use inversions on it.\n");
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goto err3;
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}
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ret = -ENOMEM;
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help = nf_ct_helper_ext_add(ct, GFP_KERNEL);
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if (help == NULL)
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goto err3;
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ret = -ENOENT;
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help->helper = nf_conntrack_helper_try_module_get(info->helper,
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par->family,
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proto);
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if (help->helper == NULL) {
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pr_info("No such helper \"%s\"\n", info->helper);
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goto err3;
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}
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}
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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if (info->timeout[0]) {
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typeof(nf_ct_timeout_find_get_hook) timeout_find_get;
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struct nf_conn_timeout *timeout_ext;
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rcu_read_lock();
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timeout_find_get =
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rcu_dereference(nf_ct_timeout_find_get_hook);
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if (timeout_find_get) {
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const struct ipt_entry *e = par->entryinfo;
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struct nf_conntrack_l4proto *l4proto;
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if (e->ip.invflags & IPT_INV_PROTO) {
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ret = -EINVAL;
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pr_info("You cannot use inversion on "
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"L4 protocol\n");
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goto err4;
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}
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timeout = timeout_find_get(info->timeout);
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if (timeout == NULL) {
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ret = -ENOENT;
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pr_info("No such timeout policy \"%s\"\n",
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info->timeout);
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goto err4;
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}
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if (timeout->l3num != par->family) {
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ret = -EINVAL;
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pr_info("Timeout policy `%s' can only be "
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"used by L3 protocol number %d\n",
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info->timeout, timeout->l3num);
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goto err5;
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}
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/* Make sure the timeout policy matches any existing
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* protocol tracker, otherwise default to generic.
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*/
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l4proto = __nf_ct_l4proto_find(par->family,
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e->ip.proto);
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if (timeout->l4proto->l4proto != l4proto->l4proto) {
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ret = -EINVAL;
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pr_info("Timeout policy `%s' can only be "
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"used by L4 protocol number %d\n",
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info->timeout,
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timeout->l4proto->l4proto);
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goto err5;
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}
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timeout_ext = nf_ct_timeout_ext_add(ct, timeout,
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GFP_ATOMIC);
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if (timeout_ext == NULL) {
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ret = -ENOMEM;
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goto err5;
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}
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} else {
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ret = -ENOENT;
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pr_info("Timeout policy base is empty\n");
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goto err4;
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}
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rcu_read_unlock();
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}
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#endif
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__set_bit(IPS_TEMPLATE_BIT, &ct->status);
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__set_bit(IPS_CONFIRMED_BIT, &ct->status);
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out:
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info->ct = ct;
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return 0;
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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err5:
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__xt_ct_tg_timeout_put(timeout);
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err4:
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rcu_read_unlock();
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#endif
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err3:
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nf_conntrack_free(ct);
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err2:
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nf_ct_l3proto_module_put(par->family);
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err1:
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return ret;
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}
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static void xt_ct_tg_destroy_v0(const struct xt_tgdtor_param *par)
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{
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struct xt_ct_target_info *info = par->targinfo;
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struct nf_conn *ct = info->ct;
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struct nf_conn_help *help;
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if (!nf_ct_is_untracked(ct)) {
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help = nfct_help(ct);
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if (help)
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module_put(help->helper->me);
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nf_ct_l3proto_module_put(par->family);
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}
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nf_ct_put(info->ct);
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}
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static void xt_ct_tg_destroy_v1(const struct xt_tgdtor_param *par)
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{
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struct xt_ct_target_info_v1 *info = par->targinfo;
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struct nf_conn *ct = info->ct;
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struct nf_conn_help *help;
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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struct nf_conn_timeout *timeout_ext;
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typeof(nf_ct_timeout_put_hook) timeout_put;
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#endif
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if (!nf_ct_is_untracked(ct)) {
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help = nfct_help(ct);
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if (help)
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module_put(help->helper->me);
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nf_ct_l3proto_module_put(par->family);
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#ifdef CONFIG_NF_CONNTRACK_TIMEOUT
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rcu_read_lock();
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timeout_put = rcu_dereference(nf_ct_timeout_put_hook);
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if (timeout_put) {
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timeout_ext = nf_ct_timeout_find(ct);
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if (timeout_ext)
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timeout_put(timeout_ext->timeout);
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}
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rcu_read_unlock();
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#endif
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}
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nf_ct_put(info->ct);
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}
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static struct xt_target xt_ct_tg_reg[] __read_mostly = {
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{
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.name = "CT",
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.family = NFPROTO_UNSPEC,
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.targetsize = sizeof(struct xt_ct_target_info),
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.checkentry = xt_ct_tg_check_v0,
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.destroy = xt_ct_tg_destroy_v0,
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.target = xt_ct_target_v0,
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.table = "raw",
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.me = THIS_MODULE,
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},
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{
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.name = "CT",
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.family = NFPROTO_UNSPEC,
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.revision = 1,
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.targetsize = sizeof(struct xt_ct_target_info_v1),
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.checkentry = xt_ct_tg_check_v1,
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.destroy = xt_ct_tg_destroy_v1,
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.target = xt_ct_target_v1,
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.table = "raw",
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.me = THIS_MODULE,
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},
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};
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static int __init xt_ct_tg_init(void)
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{
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return xt_register_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
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}
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static void __exit xt_ct_tg_exit(void)
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{
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xt_unregister_targets(xt_ct_tg_reg, ARRAY_SIZE(xt_ct_tg_reg));
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}
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module_init(xt_ct_tg_init);
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module_exit(xt_ct_tg_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("Xtables: connection tracking target");
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MODULE_ALIAS("ipt_CT");
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MODULE_ALIAS("ip6t_CT");
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