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/* Structure dynamic extension infrastructure
* Copyright (C) 2004 Rusty Russell IBM Corporation
* Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
* Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/kmemleak.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/rcupdate.h>
#include <linux/slab.h>
#include <linux/skbuff.h>
#include <net/netfilter/nf_conntrack_extend.h>
static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM];
static DEFINE_MUTEX(nf_ct_ext_type_mutex);
#define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */
void nf_ct_ext_destroy(struct nf_conn *ct)
{
unsigned int i;
struct nf_ct_ext_type *t;
for (i = 0; i < NF_CT_EXT_NUM; i++) {
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[i]);
/* Here the nf_ct_ext_type might have been unregisterd.
* I.e., it has responsible to cleanup private
* area in all conntracks when it is unregisterd.
*/
if (t && t->destroy)
t->destroy(ct);
rcu_read_unlock();
}
}
EXPORT_SYMBOL(nf_ct_ext_destroy);
void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
{
unsigned int newlen, newoff, oldlen, alloc;
struct nf_ct_ext *old, *new;
struct nf_ct_ext_type *t;
/* Conntrack must not be confirmed to avoid races on reallocation. */
WARN_ON(nf_ct_is_confirmed(ct));
old = ct->ext;
if (old) {
if (__nf_ct_ext_exist(old, id))
return NULL;
oldlen = old->len;
} else {
oldlen = sizeof(*new);
}
rcu_read_lock();
t = rcu_dereference(nf_ct_ext_types[id]);
if (!t) {
rcu_read_unlock();
return NULL;
}
newoff = ALIGN(oldlen, t->align);
newlen = newoff + t->len;
rcu_read_unlock();
alloc = max(newlen, NF_CT_EXT_PREALLOC);
kmemleak_not_leak(old);
new = __krealloc(old, alloc, gfp);
if (!new)
return NULL;
if (!old) {
memset(new->offset, 0, sizeof(new->offset));
ct->ext = new;
} else if (new != old) {
kfree_rcu(old, rcu);
rcu_assign_pointer(ct->ext, new);
}
new->offset[id] = newoff;
new->len = newlen;
memset((void *)new + newoff, 0, newlen - newoff);
return (void *)new + newoff;
}
EXPORT_SYMBOL(nf_ct_ext_add);
/* This MUST be called in process context. */
int nf_ct_extend_register(const struct nf_ct_ext_type *type)
{
int ret = 0;
mutex_lock(&nf_ct_ext_type_mutex);
if (nf_ct_ext_types[type->id]) {
ret = -EBUSY;
goto out;
}
rcu_assign_pointer(nf_ct_ext_types[type->id], type);
out:
mutex_unlock(&nf_ct_ext_type_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(nf_ct_extend_register);
/* This MUST be called in process context. */
void nf_ct_extend_unregister(const struct nf_ct_ext_type *type)
{
mutex_lock(&nf_ct_ext_type_mutex);
RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL);
mutex_unlock(&nf_ct_ext_type_mutex);
synchronize_rcu();
}
EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);
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