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ecfab2c9 YK |
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> | |
5 | * | |
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. | |
10 | */ | |
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> | |
18 | ||
0906a372 | 19 | static struct nf_ct_ext_type __rcu *nf_ct_ext_types[NF_CT_EXT_NUM]; |
ecfab2c9 YK |
20 | static DEFINE_MUTEX(nf_ct_ext_type_mutex); |
21 | ||
ecfab2c9 YK |
22 | void __nf_ct_ext_destroy(struct nf_conn *ct) |
23 | { | |
24 | unsigned int i; | |
25 | struct nf_ct_ext_type *t; | |
ee92d378 | 26 | struct nf_ct_ext *ext = ct->ext; |
ecfab2c9 YK |
27 | |
28 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
ee92d378 | 29 | if (!__nf_ct_ext_exist(ext, i)) |
ecfab2c9 YK |
30 | continue; |
31 | ||
32 | rcu_read_lock(); | |
33 | t = rcu_dereference(nf_ct_ext_types[i]); | |
34 | ||
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. | |
38 | */ | |
39 | if (t && t->destroy) | |
40 | t->destroy(ct); | |
41 | rcu_read_unlock(); | |
42 | } | |
43 | } | |
44 | EXPORT_SYMBOL(__nf_ct_ext_destroy); | |
45 | ||
46 | static void * | |
3cf4c7e3 PNA |
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) | |
ecfab2c9 | 49 | { |
019f692e | 50 | unsigned int off, len; |
ecfab2c9 | 51 | struct nf_ct_ext_type *t; |
15cdeada | 52 | size_t alloc_size; |
ecfab2c9 YK |
53 | |
54 | rcu_read_lock(); | |
55 | t = rcu_dereference(nf_ct_ext_types[id]); | |
9c3f3794 LZ |
56 | if (!t) { |
57 | rcu_read_unlock(); | |
58 | return NULL; | |
59 | } | |
60 | ||
ecfab2c9 | 61 | off = ALIGN(sizeof(struct nf_ct_ext), t->align); |
3cf4c7e3 PNA |
62 | len = off + t->len + var_alloc_len; |
63 | alloc_size = t->alloc_size + var_alloc_len; | |
ecfab2c9 YK |
64 | rcu_read_unlock(); |
65 | ||
15cdeada | 66 | *ext = kzalloc(alloc_size, gfp); |
ecfab2c9 YK |
67 | if (!*ext) |
68 | return NULL; | |
69 | ||
70 | (*ext)->offset[id] = off; | |
71 | (*ext)->len = len; | |
ecfab2c9 YK |
72 | |
73 | return (void *)(*ext) + off; | |
74 | } | |
75 | ||
3cf4c7e3 PNA |
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) | |
ecfab2c9 | 78 | { |
ee92d378 | 79 | struct nf_ct_ext *old, *new; |
7c966435 | 80 | int newlen, newoff; |
ecfab2c9 YK |
81 | struct nf_ct_ext_type *t; |
82 | ||
55871d04 PM |
83 | /* Conntrack must not be confirmed to avoid races on reallocation. */ |
84 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); | |
85 | ||
ee92d378 CG |
86 | old = ct->ext; |
87 | if (!old) | |
3cf4c7e3 | 88 | return nf_ct_ext_create(&ct->ext, id, var_alloc_len, gfp); |
ecfab2c9 | 89 | |
ee92d378 | 90 | if (__nf_ct_ext_exist(old, id)) |
ecfab2c9 YK |
91 | return NULL; |
92 | ||
93 | rcu_read_lock(); | |
94 | t = rcu_dereference(nf_ct_ext_types[id]); | |
9c3f3794 LZ |
95 | if (!t) { |
96 | rcu_read_unlock(); | |
97 | return NULL; | |
98 | } | |
ecfab2c9 | 99 | |
ee92d378 | 100 | newoff = ALIGN(old->len, t->align); |
3cf4c7e3 | 101 | newlen = newoff + t->len + var_alloc_len; |
ecfab2c9 YK |
102 | rcu_read_unlock(); |
103 | ||
ee92d378 | 104 | new = __krealloc(old, newlen, gfp); |
31d8519c PE |
105 | if (!new) |
106 | return NULL; | |
ecfab2c9 | 107 | |
ee92d378 | 108 | if (new != old) { |
1f8d36a1 | 109 | kfree_rcu(old, rcu); |
7c966435 | 110 | rcu_assign_pointer(ct->ext, new); |
ecfab2c9 YK |
111 | } |
112 | ||
6c64825b PM |
113 | new->offset[id] = newoff; |
114 | new->len = newlen; | |
115 | memset((void *)new + newoff, 0, newlen - newoff); | |
116 | return (void *)new + newoff; | |
ecfab2c9 | 117 | } |
3cf4c7e3 | 118 | EXPORT_SYMBOL(__nf_ct_ext_add_length); |
ecfab2c9 YK |
119 | |
120 | static void update_alloc_size(struct nf_ct_ext_type *type) | |
121 | { | |
122 | int i, j; | |
123 | struct nf_ct_ext_type *t1, *t2; | |
124 | enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1; | |
125 | ||
126 | /* unnecessary to update all types */ | |
127 | if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) { | |
128 | min = type->id; | |
129 | max = type->id; | |
130 | } | |
131 | ||
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++) { | |
c5d277d2 ED |
135 | t1 = rcu_dereference_protected(nf_ct_ext_types[i], |
136 | lockdep_is_held(&nf_ct_ext_type_mutex)); | |
ecfab2c9 YK |
137 | if (!t1) |
138 | continue; | |
139 | ||
3b236880 CG |
140 | t1->alloc_size = ALIGN(sizeof(struct nf_ct_ext), t1->align) + |
141 | t1->len; | |
ecfab2c9 | 142 | for (j = 0; j < NF_CT_EXT_NUM; j++) { |
c5d277d2 ED |
143 | t2 = rcu_dereference_protected(nf_ct_ext_types[j], |
144 | lockdep_is_held(&nf_ct_ext_type_mutex)); | |
ecfab2c9 YK |
145 | if (t2 == NULL || t2 == t1 || |
146 | (t2->flags & NF_CT_EXT_F_PREALLOC) == 0) | |
147 | continue; | |
148 | ||
149 | t1->alloc_size = ALIGN(t1->alloc_size, t2->align) | |
150 | + t2->len; | |
151 | } | |
ecfab2c9 YK |
152 | } |
153 | } | |
154 | ||
155 | /* This MUST be called in process context. */ | |
156 | int nf_ct_extend_register(struct nf_ct_ext_type *type) | |
157 | { | |
158 | int ret = 0; | |
159 | ||
160 | mutex_lock(&nf_ct_ext_type_mutex); | |
161 | if (nf_ct_ext_types[type->id]) { | |
162 | ret = -EBUSY; | |
163 | goto out; | |
164 | } | |
165 | ||
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) | |
169 | + type->len; | |
cf778b00 | 170 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); |
ecfab2c9 YK |
171 | update_alloc_size(type); |
172 | out: | |
173 | mutex_unlock(&nf_ct_ext_type_mutex); | |
174 | return ret; | |
175 | } | |
176 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
177 | ||
178 | /* This MUST be called in process context. */ | |
179 | void nf_ct_extend_unregister(struct nf_ct_ext_type *type) | |
180 | { | |
181 | mutex_lock(&nf_ct_ext_type_mutex); | |
a9b3cd7f | 182 | RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL); |
ecfab2c9 YK |
183 | update_alloc_size(type); |
184 | mutex_unlock(&nf_ct_ext_type_mutex); | |
9c3f3794 | 185 | synchronize_rcu(); |
ecfab2c9 YK |
186 | } |
187 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |