1 /* Structure dynamic extension infrastructure
2 * Copyright (C) 2004 Rusty Russell IBM Corporation
3 * Copyright (C) 2007 Netfilter Core Team <coreteam@netfilter.org>
4 * Copyright (C) 2007 USAGI/WIDE Project <http://www.linux-ipv6.org>
6 * This program is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU General Public License
8 * as published by the Free Software Foundation; either version
9 * 2 of the License, or (at your option) any later version.
11 #include <linux/kernel.h>
12 #include <linux/module.h>
13 #include <linux/mutex.h>
14 #include <linux/rcupdate.h>
15 #include <linux/slab.h>
16 #include <linux/skbuff.h>
17 #include <net/netfilter/nf_conntrack_extend.h>
19 static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM];
20 static DEFINE_MUTEX(nf_ct_ext_type_mutex);
22 void __nf_ct_ext_destroy(struct nf_conn *ct)
25 struct nf_ct_ext_type *t;
26 struct nf_ct_ext *ext = ct->ext;
28 for (i = 0; i < NF_CT_EXT_NUM; i++) {
29 if (!__nf_ct_ext_exist(ext, i))
33 t = rcu_dereference(nf_ct_ext_types[i]);
35 /* Here the nf_ct_ext_type might have been unregisterd.
36 * I.e., it has responsible to cleanup private
37 * area in all conntracks when it is unregisterd.
44 EXPORT_SYMBOL(__nf_ct_ext_destroy);
47 nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id,
48 size_t var_alloc_len, gfp_t gfp)
50 unsigned int off, len;
51 struct nf_ct_ext_type *t;
55 t = rcu_dereference(nf_ct_ext_types[id]);
61 off = ALIGN(sizeof(struct nf_ct_ext), t->align);
62 len = off + t->len + var_alloc_len;
63 alloc_size = t->alloc_size + var_alloc_len;
66 *ext = kzalloc(alloc_size, gfp);
70 (*ext)->offset[id] = off;
73 return (void *)(*ext) + off;
76 void *__nf_ct_ext_add_length(struct nf_conn *ct, enum nf_ct_ext_id id,
77 size_t var_alloc_len, gfp_t gfp)
79 struct nf_ct_ext *old, *new;
81 struct nf_ct_ext_type *t;
83 /* Conntrack must not be confirmed to avoid races on reallocation. */
84 NF_CT_ASSERT(!nf_ct_is_confirmed(ct));
88 return nf_ct_ext_create(&ct->ext, id, var_alloc_len, gfp);
90 if (__nf_ct_ext_exist(old, id))
94 t = rcu_dereference(nf_ct_ext_types[id]);
100 newoff = ALIGN(old->len, t->align);
101 newlen = newoff + t->len + var_alloc_len;
104 new = __krealloc(old, newlen, gfp);
110 rcu_assign_pointer(ct->ext, new);
113 new->offset[id] = newoff;
115 memset((void *)new + newoff, 0, newlen - newoff);
116 return (void *)new + newoff;
118 EXPORT_SYMBOL(__nf_ct_ext_add_length);
120 static void update_alloc_size(struct nf_ct_ext_type *type)
123 struct nf_ct_ext_type *t1, *t2;
124 enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1;
126 /* unnecessary to update all types */
127 if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) {
132 /* This assumes that extended areas in conntrack for the types
133 whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
134 for (i = min; i <= max; i++) {
135 t1 = rcu_dereference_protected(nf_ct_ext_types[i],
136 lockdep_is_held(&nf_ct_ext_type_mutex));
140 t1->alloc_size = ALIGN(sizeof(struct nf_ct_ext), t1->align) +
142 for (j = 0; j < NF_CT_EXT_NUM; j++) {
143 t2 = rcu_dereference_protected(nf_ct_ext_types[j],
144 lockdep_is_held(&nf_ct_ext_type_mutex));
145 if (t2 == NULL || t2 == t1 ||
146 (t2->flags & NF_CT_EXT_F_PREALLOC) == 0)
149 t1->alloc_size = ALIGN(t1->alloc_size, t2->align)
155 /* This MUST be called in process context. */
156 int nf_ct_extend_register(struct nf_ct_ext_type *type)
160 mutex_lock(&nf_ct_ext_type_mutex);
161 if (nf_ct_ext_types[type->id]) {
166 /* This ensures that nf_ct_ext_create() can allocate enough area
167 before updating alloc_size */
168 type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align)
170 rcu_assign_pointer(nf_ct_ext_types[type->id], type);
171 update_alloc_size(type);
173 mutex_unlock(&nf_ct_ext_type_mutex);
176 EXPORT_SYMBOL_GPL(nf_ct_extend_register);
178 /* This MUST be called in process context. */
179 void nf_ct_extend_unregister(struct nf_ct_ext_type *type)
181 mutex_lock(&nf_ct_ext_type_mutex);
182 RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL);
183 update_alloc_size(type);
184 mutex_unlock(&nf_ct_ext_type_mutex);
187 EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);