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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 | ||
68b80f11 PM |
71 | static void __nf_ct_ext_free_rcu(struct rcu_head *head) |
72 | { | |
73 | struct nf_ct_ext *ext = container_of(head, struct nf_ct_ext, rcu); | |
74 | kfree(ext); | |
75 | } | |
76 | ||
ecfab2c9 YK |
77 | void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) |
78 | { | |
ee92d378 | 79 | struct nf_ct_ext *old, *new; |
ecfab2c9 YK |
80 | int i, newlen, newoff; |
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) | |
ecfab2c9 YK |
88 | return nf_ct_ext_create(&ct->ext, id, gfp); |
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]); | |
95 | BUG_ON(t == NULL); | |
96 | ||
ee92d378 | 97 | newoff = ALIGN(old->len, t->align); |
ecfab2c9 YK |
98 | newlen = newoff + t->len; |
99 | rcu_read_unlock(); | |
100 | ||
ee92d378 | 101 | new = __krealloc(old, newlen, gfp); |
31d8519c PE |
102 | if (!new) |
103 | return NULL; | |
ecfab2c9 | 104 | |
ee92d378 | 105 | if (new != old) { |
ecfab2c9 | 106 | for (i = 0; i < NF_CT_EXT_NUM; i++) { |
ee92d378 | 107 | if (!__nf_ct_ext_exist(old, i)) |
ecfab2c9 YK |
108 | continue; |
109 | ||
110 | rcu_read_lock(); | |
111 | t = rcu_dereference(nf_ct_ext_types[i]); | |
112 | if (t && t->move) | |
86577c66 | 113 | t->move((void *)new + new->offset[i], |
ee92d378 | 114 | (void *)old + old->offset[i]); |
ecfab2c9 YK |
115 | rcu_read_unlock(); |
116 | } | |
ee92d378 | 117 | call_rcu(&old->rcu, __nf_ct_ext_free_rcu); |
ecfab2c9 YK |
118 | ct->ext = new; |
119 | } | |
120 | ||
6c64825b PM |
121 | new->offset[id] = newoff; |
122 | new->len = newlen; | |
123 | memset((void *)new + newoff, 0, newlen - newoff); | |
124 | return (void *)new + newoff; | |
ecfab2c9 YK |
125 | } |
126 | EXPORT_SYMBOL(__nf_ct_ext_add); | |
127 | ||
128 | static void update_alloc_size(struct nf_ct_ext_type *type) | |
129 | { | |
130 | int i, j; | |
131 | struct nf_ct_ext_type *t1, *t2; | |
132 | enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1; | |
133 | ||
134 | /* unnecessary to update all types */ | |
135 | if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) { | |
136 | min = type->id; | |
137 | max = type->id; | |
138 | } | |
139 | ||
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]; | |
144 | if (!t1) | |
145 | continue; | |
146 | ||
147 | t1->alloc_size = sizeof(struct nf_ct_ext) | |
148 | + ALIGN(sizeof(struct nf_ct_ext), t1->align) | |
149 | + t1->len; | |
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) | |
154 | continue; | |
155 | ||
156 | t1->alloc_size = ALIGN(t1->alloc_size, t2->align) | |
157 | + t2->len; | |
158 | } | |
ecfab2c9 YK |
159 | } |
160 | } | |
161 | ||
162 | /* This MUST be called in process context. */ | |
163 | int nf_ct_extend_register(struct nf_ct_ext_type *type) | |
164 | { | |
165 | int ret = 0; | |
166 | ||
167 | mutex_lock(&nf_ct_ext_type_mutex); | |
168 | if (nf_ct_ext_types[type->id]) { | |
169 | ret = -EBUSY; | |
170 | goto out; | |
171 | } | |
172 | ||
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) | |
176 | + type->len; | |
177 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); | |
178 | update_alloc_size(type); | |
179 | out: | |
180 | mutex_unlock(&nf_ct_ext_type_mutex); | |
181 | return ret; | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
184 | ||
185 | /* This MUST be called in process context. */ | |
186 | void nf_ct_extend_unregister(struct nf_ct_ext_type *type) | |
187 | { | |
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); | |
308ff823 | 192 | rcu_barrier(); /* Wait for completion of call_rcu()'s */ |
ecfab2c9 YK |
193 | } |
194 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |