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
*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
;
27 for (i
= 0; i
< NF_CT_EXT_NUM
; i
++) {
28 if (!nf_ct_ext_exist(ct
, i
))
32 t
= rcu_dereference(nf_ct_ext_types
[i
]);
34 /* Here the nf_ct_ext_type might have been unregisterd.
35 * I.e., it has responsible to cleanup private
36 * area in all conntracks when it is unregisterd.
43 EXPORT_SYMBOL(__nf_ct_ext_destroy
);
46 nf_ct_ext_create(struct nf_ct_ext
**ext
, enum nf_ct_ext_id id
, gfp_t gfp
)
48 unsigned int off
, len
;
49 struct nf_ct_ext_type
*t
;
52 t
= rcu_dereference(nf_ct_ext_types
[id
]);
54 off
= ALIGN(sizeof(struct nf_ct_ext
), t
->align
);
58 *ext
= kzalloc(t
->alloc_size
, gfp
);
62 INIT_RCU_HEAD(&(*ext
)->rcu
);
63 (*ext
)->offset
[id
] = off
;
66 return (void *)(*ext
) + off
;
69 static void __nf_ct_ext_free_rcu(struct rcu_head
*head
)
71 struct nf_ct_ext
*ext
= container_of(head
, struct nf_ct_ext
, rcu
);
75 void *__nf_ct_ext_add(struct nf_conn
*ct
, enum nf_ct_ext_id id
, gfp_t gfp
)
77 struct nf_ct_ext
*new;
78 int i
, newlen
, newoff
;
79 struct nf_ct_ext_type
*t
;
81 /* Conntrack must not be confirmed to avoid races on reallocation. */
82 NF_CT_ASSERT(!nf_ct_is_confirmed(ct
));
85 return nf_ct_ext_create(&ct
->ext
, id
, gfp
);
87 if (nf_ct_ext_exist(ct
, id
))
91 t
= rcu_dereference(nf_ct_ext_types
[id
]);
94 newoff
= ALIGN(ct
->ext
->len
, t
->align
);
95 newlen
= newoff
+ t
->len
;
98 new = __krealloc(ct
->ext
, newlen
, gfp
);
102 if (new != ct
->ext
) {
103 for (i
= 0; i
< NF_CT_EXT_NUM
; i
++) {
104 if (!nf_ct_ext_exist(ct
, i
))
108 t
= rcu_dereference(nf_ct_ext_types
[i
]);
110 t
->move((void *)new + new->offset
[i
],
111 (void *)ct
->ext
+ ct
->ext
->offset
[i
]);
114 call_rcu(&ct
->ext
->rcu
, __nf_ct_ext_free_rcu
);
118 new->offset
[id
] = newoff
;
120 memset((void *)new + newoff
, 0, newlen
- newoff
);
121 return (void *)new + newoff
;
123 EXPORT_SYMBOL(__nf_ct_ext_add
);
125 static void update_alloc_size(struct nf_ct_ext_type
*type
)
128 struct nf_ct_ext_type
*t1
, *t2
;
129 enum nf_ct_ext_id min
= 0, max
= NF_CT_EXT_NUM
- 1;
131 /* unnecessary to update all types */
132 if ((type
->flags
& NF_CT_EXT_F_PREALLOC
) == 0) {
137 /* This assumes that extended areas in conntrack for the types
138 whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */
139 for (i
= min
; i
<= max
; i
++) {
140 t1
= nf_ct_ext_types
[i
];
144 t1
->alloc_size
= sizeof(struct nf_ct_ext
)
145 + ALIGN(sizeof(struct nf_ct_ext
), t1
->align
)
147 for (j
= 0; j
< NF_CT_EXT_NUM
; j
++) {
148 t2
= nf_ct_ext_types
[j
];
149 if (t2
== NULL
|| t2
== t1
||
150 (t2
->flags
& NF_CT_EXT_F_PREALLOC
) == 0)
153 t1
->alloc_size
= ALIGN(t1
->alloc_size
, t2
->align
)
159 /* This MUST be called in process context. */
160 int nf_ct_extend_register(struct nf_ct_ext_type
*type
)
164 mutex_lock(&nf_ct_ext_type_mutex
);
165 if (nf_ct_ext_types
[type
->id
]) {
170 /* This ensures that nf_ct_ext_create() can allocate enough area
171 before updating alloc_size */
172 type
->alloc_size
= ALIGN(sizeof(struct nf_ct_ext
), type
->align
)
174 rcu_assign_pointer(nf_ct_ext_types
[type
->id
], type
);
175 update_alloc_size(type
);
177 mutex_unlock(&nf_ct_ext_type_mutex
);
180 EXPORT_SYMBOL_GPL(nf_ct_extend_register
);
182 /* This MUST be called in process context. */
183 void nf_ct_extend_unregister(struct nf_ct_ext_type
*type
)
185 mutex_lock(&nf_ct_ext_type_mutex
);
186 rcu_assign_pointer(nf_ct_ext_types
[type
->id
], NULL
);
187 update_alloc_size(type
);
188 mutex_unlock(&nf_ct_ext_type_mutex
);
189 rcu_barrier(); /* Wait for completion of call_rcu()'s */
191 EXPORT_SYMBOL_GPL(nf_ct_extend_unregister
);
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