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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 * | |
47 | nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp) | |
48 | { | |
019f692e | 49 | unsigned int off, len; |
ecfab2c9 | 50 | struct nf_ct_ext_type *t; |
15cdeada | 51 | size_t alloc_size; |
ecfab2c9 YK |
52 | |
53 | rcu_read_lock(); | |
54 | t = rcu_dereference(nf_ct_ext_types[id]); | |
55 | BUG_ON(t == NULL); | |
56 | off = ALIGN(sizeof(struct nf_ct_ext), t->align); | |
57 | len = off + t->len; | |
15cdeada | 58 | alloc_size = t->alloc_size; |
ecfab2c9 YK |
59 | rcu_read_unlock(); |
60 | ||
15cdeada | 61 | *ext = kzalloc(alloc_size, gfp); |
ecfab2c9 YK |
62 | if (!*ext) |
63 | return NULL; | |
64 | ||
65 | (*ext)->offset[id] = off; | |
66 | (*ext)->len = len; | |
ecfab2c9 YK |
67 | |
68 | return (void *)(*ext) + off; | |
69 | } | |
70 | ||
71 | void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) | |
72 | { | |
ee92d378 | 73 | struct nf_ct_ext *old, *new; |
ecfab2c9 YK |
74 | int i, newlen, newoff; |
75 | struct nf_ct_ext_type *t; | |
76 | ||
55871d04 PM |
77 | /* Conntrack must not be confirmed to avoid races on reallocation. */ |
78 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); | |
79 | ||
ee92d378 CG |
80 | old = ct->ext; |
81 | if (!old) | |
ecfab2c9 YK |
82 | return nf_ct_ext_create(&ct->ext, id, gfp); |
83 | ||
ee92d378 | 84 | if (__nf_ct_ext_exist(old, id)) |
ecfab2c9 YK |
85 | return NULL; |
86 | ||
87 | rcu_read_lock(); | |
88 | t = rcu_dereference(nf_ct_ext_types[id]); | |
89 | BUG_ON(t == NULL); | |
90 | ||
ee92d378 | 91 | newoff = ALIGN(old->len, t->align); |
ecfab2c9 YK |
92 | newlen = newoff + t->len; |
93 | rcu_read_unlock(); | |
94 | ||
ee92d378 | 95 | new = __krealloc(old, newlen, gfp); |
31d8519c PE |
96 | if (!new) |
97 | return NULL; | |
ecfab2c9 | 98 | |
ee92d378 | 99 | if (new != old) { |
ecfab2c9 | 100 | for (i = 0; i < NF_CT_EXT_NUM; i++) { |
ee92d378 | 101 | if (!__nf_ct_ext_exist(old, i)) |
ecfab2c9 YK |
102 | continue; |
103 | ||
104 | rcu_read_lock(); | |
105 | t = rcu_dereference(nf_ct_ext_types[i]); | |
106 | if (t && t->move) | |
86577c66 | 107 | t->move((void *)new + new->offset[i], |
ee92d378 | 108 | (void *)old + old->offset[i]); |
ecfab2c9 YK |
109 | rcu_read_unlock(); |
110 | } | |
1f8d36a1 | 111 | kfree_rcu(old, rcu); |
ecfab2c9 YK |
112 | ct->ext = new; |
113 | } | |
114 | ||
6c64825b PM |
115 | new->offset[id] = newoff; |
116 | new->len = newlen; | |
117 | memset((void *)new + newoff, 0, newlen - newoff); | |
118 | return (void *)new + newoff; | |
ecfab2c9 YK |
119 | } |
120 | EXPORT_SYMBOL(__nf_ct_ext_add); | |
121 | ||
122 | static void update_alloc_size(struct nf_ct_ext_type *type) | |
123 | { | |
124 | int i, j; | |
125 | struct nf_ct_ext_type *t1, *t2; | |
126 | enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1; | |
127 | ||
128 | /* unnecessary to update all types */ | |
129 | if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) { | |
130 | min = type->id; | |
131 | max = type->id; | |
132 | } | |
133 | ||
134 | /* This assumes that extended areas in conntrack for the types | |
135 | whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */ | |
136 | for (i = min; i <= max; i++) { | |
c5d277d2 ED |
137 | t1 = rcu_dereference_protected(nf_ct_ext_types[i], |
138 | lockdep_is_held(&nf_ct_ext_type_mutex)); | |
ecfab2c9 YK |
139 | if (!t1) |
140 | continue; | |
141 | ||
3b236880 CG |
142 | t1->alloc_size = ALIGN(sizeof(struct nf_ct_ext), t1->align) + |
143 | t1->len; | |
ecfab2c9 | 144 | for (j = 0; j < NF_CT_EXT_NUM; j++) { |
c5d277d2 ED |
145 | t2 = rcu_dereference_protected(nf_ct_ext_types[j], |
146 | lockdep_is_held(&nf_ct_ext_type_mutex)); | |
ecfab2c9 YK |
147 | if (t2 == NULL || t2 == t1 || |
148 | (t2->flags & NF_CT_EXT_F_PREALLOC) == 0) | |
149 | continue; | |
150 | ||
151 | t1->alloc_size = ALIGN(t1->alloc_size, t2->align) | |
152 | + t2->len; | |
153 | } | |
ecfab2c9 YK |
154 | } |
155 | } | |
156 | ||
157 | /* This MUST be called in process context. */ | |
158 | int nf_ct_extend_register(struct nf_ct_ext_type *type) | |
159 | { | |
160 | int ret = 0; | |
161 | ||
162 | mutex_lock(&nf_ct_ext_type_mutex); | |
163 | if (nf_ct_ext_types[type->id]) { | |
164 | ret = -EBUSY; | |
165 | goto out; | |
166 | } | |
167 | ||
168 | /* This ensures that nf_ct_ext_create() can allocate enough area | |
169 | before updating alloc_size */ | |
170 | type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align) | |
171 | + type->len; | |
172 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); | |
173 | update_alloc_size(type); | |
174 | out: | |
175 | mutex_unlock(&nf_ct_ext_type_mutex); | |
176 | return ret; | |
177 | } | |
178 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
179 | ||
180 | /* This MUST be called in process context. */ | |
181 | void nf_ct_extend_unregister(struct nf_ct_ext_type *type) | |
182 | { | |
183 | mutex_lock(&nf_ct_ext_type_mutex); | |
184 | rcu_assign_pointer(nf_ct_ext_types[type->id], NULL); | |
185 | update_alloc_size(type); | |
186 | mutex_unlock(&nf_ct_ext_type_mutex); | |
308ff823 | 187 | rcu_barrier(); /* Wait for completion of call_rcu()'s */ |
ecfab2c9 YK |
188 | } |
189 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |