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, gfp_t gfp)
49 unsigned int off, len;
50 struct nf_ct_ext_type *t;
54 t = rcu_dereference(nf_ct_ext_types[id]);
56 off = ALIGN(sizeof(struct nf_ct_ext), t->align);
58 alloc_size = t->alloc_size;
61 *ext = kzalloc(alloc_size, gfp);
65 (*ext)->offset[id] = off;
68 return (void *)(*ext) + off;
71 static void __nf_ct_ext_free_rcu(struct rcu_head *head)
73 struct nf_ct_ext *ext = container_of(head, struct nf_ct_ext, rcu);
77 void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp)
79 struct nf_ct_ext *old, *new;
80 int i, newlen, newoff;
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, gfp);
90 if (__nf_ct_ext_exist(old, id))
94 t = rcu_dereference(nf_ct_ext_types[id]);
97 newoff = ALIGN(old->len, t->align);
98 newlen = newoff + t->len;
101 new = __krealloc(old, newlen, gfp);
106 for (i = 0; i < NF_CT_EXT_NUM; i++) {
107 if (!__nf_ct_ext_exist(old, i))
111 t = rcu_dereference(nf_ct_ext_types[i]);
113 t->move((void *)new + new->offset[i],
114 (void *)old + old->offset[i]);
117 call_rcu(&old->rcu, __nf_ct_ext_free_rcu);
121 new->offset[id] = newoff;
123 memset((void *)new + newoff, 0, newlen - newoff);
124 return (void *)new + newoff;
126 EXPORT_SYMBOL(__nf_ct_ext_add);
128 static void update_alloc_size(struct nf_ct_ext_type *type)
131 struct nf_ct_ext_type *t1, *t2;
132 enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1;
134 /* unnecessary to update all types */
135 if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) {
140 /* This assumes that extended areas in conntrack for the types
141 whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
142 for (i = min; i <= max; i++) {
143 t1 = nf_ct_ext_types[i];
147 t1->alloc_size = sizeof(struct nf_ct_ext)
148 + ALIGN(sizeof(struct nf_ct_ext), t1->align)
150 for (j = 0; j < NF_CT_EXT_NUM; j++) {
151 t2 = nf_ct_ext_types[j];
152 if (t2 == NULL || t2 == t1 ||
153 (t2->flags & NF_CT_EXT_F_PREALLOC) == 0)
156 t1->alloc_size = ALIGN(t1->alloc_size, t2->align)
162 /* This MUST be called in process context. */
163 int nf_ct_extend_register(struct nf_ct_ext_type *type)
167 mutex_lock(&nf_ct_ext_type_mutex);
168 if (nf_ct_ext_types[type->id]) {
173 /* This ensures that nf_ct_ext_create() can allocate enough area
174 before updating alloc_size */
175 type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align)
177 rcu_assign_pointer(nf_ct_ext_types[type->id], type);
178 update_alloc_size(type);
180 mutex_unlock(&nf_ct_ext_type_mutex);
183 EXPORT_SYMBOL_GPL(nf_ct_extend_register);
185 /* This MUST be called in process context. */
186 void nf_ct_extend_unregister(struct nf_ct_ext_type *type)
188 mutex_lock(&nf_ct_ext_type_mutex);
189 rcu_assign_pointer(nf_ct_ext_types[type->id], NULL);
190 update_alloc_size(type);
191 mutex_unlock(&nf_ct_ext_type_mutex);
192 rcu_barrier(); /* Wait for completion of call_rcu()'s */
194 EXPORT_SYMBOL_GPL(nf_ct_extend_unregister);