// SPDX-License-Identifier: GPL-2.0-or-later
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/* 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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#include <linux/kernel.h>
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#include <linux/kmemleak.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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kfree(ct->ext);
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}
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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_type *t;
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struct nf_ct_ext *new;
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/* Conntrack must not be confirmed to avoid races on reallocation. */
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WARN_ON(nf_ct_is_confirmed(ct));
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if (ct->ext) {
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const struct nf_ct_ext *old = ct->ext;
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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(ct->ext, alloc, gfp);
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if (!new)
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return NULL;
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if (!ct->ext)
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memset(new->offset, 0, sizeof(new->offset));
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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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ct->ext = new;
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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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