2006-11-29 01:34:59 +00:00
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/* Helper handling for netfilter. */
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
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* (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
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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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#include <linux/types.h>
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#include <linux/netfilter.h>
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#include <linux/module.h>
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#include <linux/skbuff.h>
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#include <linux/vmalloc.h>
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#include <linux/stddef.h>
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#include <linux/slab.h>
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#include <linux/random.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/netdevice.h>
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#include <net/netfilter/nf_conntrack.h>
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#include <net/netfilter/nf_conntrack_l3proto.h>
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2006-11-29 01:35:06 +00:00
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#include <net/netfilter/nf_conntrack_l4proto.h>
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2006-11-29 01:34:59 +00:00
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#include <net/netfilter/nf_conntrack_helper.h>
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#include <net/netfilter/nf_conntrack_core.h>
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2007-07-08 05:23:42 +00:00
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#include <net/netfilter/nf_conntrack_extend.h>
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2006-11-29 01:34:59 +00:00
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2007-07-08 05:36:46 +00:00
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static struct hlist_head *nf_ct_helper_hash __read_mostly;
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static unsigned int nf_ct_helper_hsize __read_mostly;
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static unsigned int nf_ct_helper_count __read_mostly;
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static int nf_ct_helper_vmalloc;
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/* Stupid hash, but collision free for the default registrations of the
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* helpers currently in the kernel. */
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static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple)
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{
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return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^
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2007-07-26 16:33:19 +00:00
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(__force __u16)tuple->src.u.all) % nf_ct_helper_hsize;
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2007-07-08 05:36:46 +00:00
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}
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2006-11-29 01:34:59 +00:00
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struct nf_conntrack_helper *
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__nf_ct_helper_find(const struct nf_conntrack_tuple *tuple)
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{
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2007-07-08 05:36:46 +00:00
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struct nf_conntrack_helper *helper;
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2007-07-08 05:31:32 +00:00
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struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) };
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2007-07-08 05:36:46 +00:00
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struct hlist_node *n;
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unsigned int h;
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2006-11-29 01:34:59 +00:00
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2007-07-08 05:36:46 +00:00
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if (!nf_ct_helper_count)
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return NULL;
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h = helper_hash(tuple);
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hlist_for_each_entry(helper, n, &nf_ct_helper_hash[h], hnode) {
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if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask))
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return helper;
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2006-11-29 01:34:59 +00:00
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}
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return NULL;
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}
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struct nf_conntrack_helper *
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2007-07-08 05:36:46 +00:00
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nf_ct_helper_find_get(const struct nf_conntrack_tuple *tuple)
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2006-11-29 01:34:59 +00:00
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{
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struct nf_conntrack_helper *helper;
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/* need nf_conntrack_lock to assure that helper exists until
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* try_module_get() is called */
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read_lock_bh(&nf_conntrack_lock);
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helper = __nf_ct_helper_find(tuple);
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if (helper) {
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/* need to increase module usage count to assure helper will
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* not go away while the caller is e.g. busy putting a
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* conntrack in the hash that uses the helper */
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if (!try_module_get(helper->me))
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helper = NULL;
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}
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read_unlock_bh(&nf_conntrack_lock);
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return helper;
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}
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2006-12-03 06:11:25 +00:00
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EXPORT_SYMBOL_GPL(nf_ct_helper_find_get);
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2006-11-29 01:34:59 +00:00
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void nf_ct_helper_put(struct nf_conntrack_helper *helper)
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{
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module_put(helper->me);
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}
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2006-12-03 06:11:25 +00:00
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EXPORT_SYMBOL_GPL(nf_ct_helper_put);
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2006-11-29 01:34:59 +00:00
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struct nf_conntrack_helper *
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__nf_conntrack_helper_find_byname(const char *name)
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{
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struct nf_conntrack_helper *h;
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2007-07-08 05:36:46 +00:00
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struct hlist_node *n;
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unsigned int i;
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2006-11-29 01:34:59 +00:00
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2007-07-08 05:36:46 +00:00
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for (i = 0; i < nf_ct_helper_hsize; i++) {
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hlist_for_each_entry(h, n, &nf_ct_helper_hash[i], hnode) {
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if (!strcmp(h->name, name))
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return h;
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}
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2006-11-29 01:34:59 +00:00
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}
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return NULL;
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}
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2006-12-03 06:11:25 +00:00
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EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname);
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2006-11-29 01:34:59 +00:00
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2007-07-08 05:35:56 +00:00
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struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp)
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{
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struct nf_conn_help *help;
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help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp);
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if (help)
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INIT_HLIST_HEAD(&help->expectations);
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else
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pr_debug("failed to add helper extension area");
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return help;
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}
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EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add);
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2006-11-29 01:34:59 +00:00
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static inline int unhelp(struct nf_conntrack_tuple_hash *i,
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const struct nf_conntrack_helper *me)
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{
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struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i);
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struct nf_conn_help *help = nfct_help(ct);
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if (help && help->helper == me) {
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nf_conntrack_event(IPCT_HELPER, ct);
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2007-06-05 19:55:27 +00:00
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rcu_assign_pointer(help->helper, NULL);
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2006-11-29 01:34:59 +00:00
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}
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return 0;
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}
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int nf_conntrack_helper_register(struct nf_conntrack_helper *me)
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{
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2007-07-08 05:36:46 +00:00
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unsigned int h = helper_hash(&me->tuple);
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2006-11-29 01:34:59 +00:00
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BUG_ON(me->timeout == 0);
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write_lock_bh(&nf_conntrack_lock);
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2007-07-08 05:36:46 +00:00
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hlist_add_head(&me->hnode, &nf_ct_helper_hash[h]);
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nf_ct_helper_count++;
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2006-11-29 01:34:59 +00:00
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write_unlock_bh(&nf_conntrack_lock);
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return 0;
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}
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2006-12-03 06:11:25 +00:00
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EXPORT_SYMBOL_GPL(nf_conntrack_helper_register);
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2006-11-29 01:34:59 +00:00
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void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me)
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{
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struct nf_conntrack_tuple_hash *h;
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2007-07-08 05:35:21 +00:00
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struct nf_conntrack_expect *exp;
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struct hlist_node *n, *next;
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unsigned int i;
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2006-11-29 01:34:59 +00:00
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/* Need write lock here, to delete helper. */
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write_lock_bh(&nf_conntrack_lock);
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2007-07-08 05:36:46 +00:00
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hlist_del(&me->hnode);
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nf_ct_helper_count--;
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2006-11-29 01:34:59 +00:00
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/* Get rid of expectations */
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2007-07-08 05:35:21 +00:00
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for (i = 0; i < nf_ct_expect_hsize; i++) {
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hlist_for_each_entry_safe(exp, n, next,
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&nf_ct_expect_hash[i], hnode) {
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struct nf_conn_help *help = nfct_help(exp->master);
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if ((help->helper == me || exp->helper == me) &&
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del_timer(&exp->timeout)) {
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nf_ct_unlink_expect(exp);
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nf_ct_expect_put(exp);
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}
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2006-11-29 01:34:59 +00:00
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}
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}
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/* Get rid of expecteds, set helpers to NULL. */
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2007-07-08 05:28:14 +00:00
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hlist_for_each_entry(h, n, &unconfirmed, hnode)
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2006-11-29 01:34:59 +00:00
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unhelp(h, me);
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for (i = 0; i < nf_conntrack_htable_size; i++) {
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2007-07-08 05:28:14 +00:00
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hlist_for_each_entry(h, n, &nf_conntrack_hash[i], hnode)
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2006-11-29 01:34:59 +00:00
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unhelp(h, me);
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}
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write_unlock_bh(&nf_conntrack_lock);
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/* Someone could be still looking at the helper in a bh. */
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synchronize_net();
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}
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2006-12-03 06:11:25 +00:00
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EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister);
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2007-07-08 05:23:42 +00:00
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2007-07-08 05:27:06 +00:00
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static struct nf_ct_ext_type helper_extend __read_mostly = {
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2007-07-08 05:23:42 +00:00
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.len = sizeof(struct nf_conn_help),
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.align = __alignof__(struct nf_conn_help),
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.id = NF_CT_EXT_HELPER,
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};
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2007-07-20 15:15:28 +00:00
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int nf_conntrack_helper_init(void)
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2007-07-08 05:23:42 +00:00
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{
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2007-07-08 05:36:46 +00:00
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int err;
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nf_ct_helper_hsize = 1; /* gets rounded up to use one page */
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nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize,
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&nf_ct_helper_vmalloc);
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if (!nf_ct_helper_hash)
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return -ENOMEM;
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err = nf_ct_extend_register(&helper_extend);
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if (err < 0)
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goto err1;
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return 0;
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err1:
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nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
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nf_ct_helper_hsize);
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return err;
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2007-07-08 05:23:42 +00:00
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}
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2007-07-20 15:15:28 +00:00
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void nf_conntrack_helper_fini(void)
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2007-07-08 05:23:42 +00:00
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{
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nf_ct_extend_unregister(&helper_extend);
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2007-07-08 05:36:46 +00:00
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nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc,
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nf_ct_helper_hsize);
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2007-07-08 05:23:42 +00:00
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}
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