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- // SPDX-License-Identifier: GPL-2.0-or-later
- /* 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>
- */
- #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();
- }
- kfree(ct->ext);
- }
- 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_type *t;
- struct nf_ct_ext *new;
- /* Conntrack must not be confirmed to avoid races on reallocation. */
- WARN_ON(nf_ct_is_confirmed(ct));
- if (ct->ext) {
- const struct nf_ct_ext *old = ct->ext;
- 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);
- new = krealloc(ct->ext, alloc, gfp);
- if (!new)
- return NULL;
- if (!ct->ext)
- memset(new->offset, 0, sizeof(new->offset));
- new->offset[id] = newoff;
- new->len = newlen;
- memset((void *)new + newoff, 0, newlen - newoff);
- ct->ext = new;
- 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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