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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 | ||
19 | static struct nf_ct_ext_type *nf_ct_ext_types[NF_CT_EXT_NUM]; | |
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; | |
26 | ||
27 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
28 | if (!nf_ct_ext_exist(ct, i)) | |
29 | continue; | |
30 | ||
31 | rcu_read_lock(); | |
32 | t = rcu_dereference(nf_ct_ext_types[i]); | |
33 | ||
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. | |
37 | */ | |
38 | if (t && t->destroy) | |
39 | t->destroy(ct); | |
40 | rcu_read_unlock(); | |
41 | } | |
42 | } | |
43 | EXPORT_SYMBOL(__nf_ct_ext_destroy); | |
44 | ||
45 | static void * | |
46 | nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp) | |
47 | { | |
019f692e | 48 | unsigned int off, len; |
ecfab2c9 YK |
49 | struct nf_ct_ext_type *t; |
50 | ||
51 | rcu_read_lock(); | |
52 | t = rcu_dereference(nf_ct_ext_types[id]); | |
53 | BUG_ON(t == NULL); | |
54 | off = ALIGN(sizeof(struct nf_ct_ext), t->align); | |
55 | len = off + t->len; | |
ecfab2c9 YK |
56 | rcu_read_unlock(); |
57 | ||
019f692e | 58 | *ext = kzalloc(t->alloc_size, gfp); |
ecfab2c9 YK |
59 | if (!*ext) |
60 | return NULL; | |
61 | ||
62 | (*ext)->offset[id] = off; | |
63 | (*ext)->len = len; | |
ecfab2c9 YK |
64 | |
65 | return (void *)(*ext) + off; | |
66 | } | |
67 | ||
68 | void *__nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) | |
69 | { | |
70 | struct nf_ct_ext *new; | |
71 | int i, newlen, newoff; | |
72 | struct nf_ct_ext_type *t; | |
73 | ||
74 | if (!ct->ext) | |
75 | return nf_ct_ext_create(&ct->ext, id, gfp); | |
76 | ||
77 | if (nf_ct_ext_exist(ct, id)) | |
78 | return NULL; | |
79 | ||
80 | rcu_read_lock(); | |
81 | t = rcu_dereference(nf_ct_ext_types[id]); | |
82 | BUG_ON(t == NULL); | |
83 | ||
84 | newoff = ALIGN(ct->ext->len, t->align); | |
85 | newlen = newoff + t->len; | |
86 | rcu_read_unlock(); | |
87 | ||
019f692e | 88 | if (newlen >= ksize(ct->ext)) { |
ecfab2c9 YK |
89 | new = kmalloc(newlen, gfp); |
90 | if (!new) | |
91 | return NULL; | |
92 | ||
93 | memcpy(new, ct->ext, ct->ext->len); | |
94 | ||
95 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
96 | if (!nf_ct_ext_exist(ct, i)) | |
97 | continue; | |
98 | ||
99 | rcu_read_lock(); | |
100 | t = rcu_dereference(nf_ct_ext_types[i]); | |
101 | if (t && t->move) | |
86577c66 PM |
102 | t->move((void *)new + new->offset[i], |
103 | (void *)ct->ext + ct->ext->offset[i]); | |
ecfab2c9 YK |
104 | rcu_read_unlock(); |
105 | } | |
106 | kfree(ct->ext); | |
ecfab2c9 YK |
107 | ct->ext = new; |
108 | } | |
109 | ||
110 | ct->ext->offset[id] = newoff; | |
111 | ct->ext->len = newlen; | |
112 | memset((void *)ct->ext + newoff, 0, newlen - newoff); | |
113 | return (void *)ct->ext + newoff; | |
114 | } | |
115 | EXPORT_SYMBOL(__nf_ct_ext_add); | |
116 | ||
117 | static void update_alloc_size(struct nf_ct_ext_type *type) | |
118 | { | |
119 | int i, j; | |
120 | struct nf_ct_ext_type *t1, *t2; | |
121 | enum nf_ct_ext_id min = 0, max = NF_CT_EXT_NUM - 1; | |
122 | ||
123 | /* unnecessary to update all types */ | |
124 | if ((type->flags & NF_CT_EXT_F_PREALLOC) == 0) { | |
125 | min = type->id; | |
126 | max = type->id; | |
127 | } | |
128 | ||
129 | /* This assumes that extended areas in conntrack for the types | |
130 | whose NF_CT_EXT_F_PREALLOC bit set are allocated in order */ | |
131 | for (i = min; i <= max; i++) { | |
132 | t1 = nf_ct_ext_types[i]; | |
133 | if (!t1) | |
134 | continue; | |
135 | ||
136 | t1->alloc_size = sizeof(struct nf_ct_ext) | |
137 | + ALIGN(sizeof(struct nf_ct_ext), t1->align) | |
138 | + t1->len; | |
139 | for (j = 0; j < NF_CT_EXT_NUM; j++) { | |
140 | t2 = nf_ct_ext_types[j]; | |
141 | if (t2 == NULL || t2 == t1 || | |
142 | (t2->flags & NF_CT_EXT_F_PREALLOC) == 0) | |
143 | continue; | |
144 | ||
145 | t1->alloc_size = ALIGN(t1->alloc_size, t2->align) | |
146 | + t2->len; | |
147 | } | |
ecfab2c9 YK |
148 | } |
149 | } | |
150 | ||
151 | /* This MUST be called in process context. */ | |
152 | int nf_ct_extend_register(struct nf_ct_ext_type *type) | |
153 | { | |
154 | int ret = 0; | |
155 | ||
156 | mutex_lock(&nf_ct_ext_type_mutex); | |
157 | if (nf_ct_ext_types[type->id]) { | |
158 | ret = -EBUSY; | |
159 | goto out; | |
160 | } | |
161 | ||
162 | /* This ensures that nf_ct_ext_create() can allocate enough area | |
163 | before updating alloc_size */ | |
164 | type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align) | |
165 | + type->len; | |
166 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); | |
167 | update_alloc_size(type); | |
168 | out: | |
169 | mutex_unlock(&nf_ct_ext_type_mutex); | |
170 | return ret; | |
171 | } | |
172 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
173 | ||
174 | /* This MUST be called in process context. */ | |
175 | void nf_ct_extend_unregister(struct nf_ct_ext_type *type) | |
176 | { | |
177 | mutex_lock(&nf_ct_ext_type_mutex); | |
178 | rcu_assign_pointer(nf_ct_ext_types[type->id], NULL); | |
179 | update_alloc_size(type); | |
180 | mutex_unlock(&nf_ct_ext_type_mutex); | |
181 | synchronize_rcu(); | |
182 | } | |
183 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |