8eeef23504
For NF_NAT_MANIP_SRC, we will insert the ct to the nat_bysource_table,
then remove it from the nat_bysource_table via nat_extend->destroy.
But now, the nat extension is attached on demand, so if the nat extension
is not attached, we will not be notified when the ct is destroyed, i.e.
we may fail to remove ct from the nat_bysource_table.
So just keep it simple, even if the extension is not attached, we will
still invoke the related ext->destroy. And this will also preserve the
flexibility for the future extension.
Fixes: 9a08ecfe74 ("netfilter: don't attach a nat extension by default")
Signed-off-by: Liping Zhang <zlpnobody@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
120 lines
3 KiB
C
120 lines
3 KiB
C
/* Structure dynamic extension infrastructure
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* Copyright (C) 2004 Rusty Russell IBM Corporation
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* Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
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* Copyright (C) 2007 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
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/rcupdate.h>
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#include <linux/slab.h>
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#include <linux/skbuff.h>
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#include <net/netfilter/nf_conntrack_extend.h>
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static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM];
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static DEFINE_MUTEX(nf_ct_ext_type_mutex);
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#define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */
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void nf_ct_ext_destroy(struct nf_conn *ct)
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{
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unsigned int i;
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struct nf_ct_ext_type *t;
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for (i = 0; i < NF_CT_EXT_NUM; i++) {
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rcu_read_lock();
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t = rcu_dereference(nf_ct_ext_types[i]);
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/* Here the nf_ct_ext_type might have been unregisterd.
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* I.e., it has responsible to cleanup private
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* area in all conntracks when it is unregisterd.
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*/
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if (t && t->destroy)
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t->destroy(ct);
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rcu_read_unlock();
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}
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}
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EXPORT_SYMBOL(nf_ct_ext_destroy);
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void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
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{
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unsigned int newlen, newoff, oldlen, alloc;
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struct nf_ct_ext *old, *new;
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struct nf_ct_ext_type *t;
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/* Conntrack must not be confirmed to avoid races on reallocation. */
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NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
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old = ct->ext;
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if (old) {
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if (__nf_ct_ext_exist(old, id))
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return NULL;
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oldlen = old->len;
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} else {
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oldlen = sizeof(*new);
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}
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rcu_read_lock();
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t = rcu_dereference(nf_ct_ext_types[id]);
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if (!t) {
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rcu_read_unlock();
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return NULL;
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}
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newoff = ALIGN(oldlen, t->align);
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newlen = newoff + t->len;
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rcu_read_unlock();
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alloc = max(newlen, NF_CT_EXT_PREALLOC);
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new = __krealloc(old, alloc, gfp);
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if (!new)
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return NULL;
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if (!old) {
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memset(new->offset, 0, sizeof(new->offset));
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ct->ext = new;
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} else if (new != old) {
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kfree_rcu(old, rcu);
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rcu_assign_pointer(ct->ext, new);
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}
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new->offset[id] = newoff;
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new->len = newlen;
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memset((void *)new + newoff, 0, newlen - newoff);
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return (void *)new + newoff;
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}
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EXPORT_SYMBOL(nf_ct_ext_add);
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/* This MUST be called in process context. */
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int nf_ct_extend_register(const struct nf_ct_ext_type *type)
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{
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int ret = 0;
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mutex_lock(&nf_ct_ext_type_mutex);
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if (nf_ct_ext_types[type->id]) {
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ret = -EBUSY;
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goto out;
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}
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rcu_assign_pointer(nf_ct_ext_types[type->id], type);
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out:
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mutex_unlock(&nf_ct_ext_type_mutex);
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return ret;
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}
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EXPORT_SYMBOL_GPL(nf_ct_extend_register);
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/* This MUST be called in process context. */
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void nf_ct_extend_unregister(const struct nf_ct_ext_type *type)
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{
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mutex_lock(&nf_ct_ext_type_mutex);
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RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL);
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mutex_unlock(&nf_ct_ext_type_mutex);
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synchronize_rcu();
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}
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EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);
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