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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 | ||
55871d04 PM |
74 | /* Conntrack must not be confirmed to avoid races on reallocation. */ |
75 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); | |
76 | ||
ecfab2c9 YK |
77 | if (!ct->ext) |
78 | return nf_ct_ext_create(&ct->ext, id, gfp); | |
79 | ||
80 | if (nf_ct_ext_exist(ct, id)) | |
81 | return NULL; | |
82 | ||
83 | rcu_read_lock(); | |
84 | t = rcu_dereference(nf_ct_ext_types[id]); | |
85 | BUG_ON(t == NULL); | |
86 | ||
87 | newoff = ALIGN(ct->ext->len, t->align); | |
88 | newlen = newoff + t->len; | |
89 | rcu_read_unlock(); | |
90 | ||
019f692e | 91 | if (newlen >= ksize(ct->ext)) { |
ecfab2c9 YK |
92 | new = kmalloc(newlen, gfp); |
93 | if (!new) | |
94 | return NULL; | |
95 | ||
96 | memcpy(new, ct->ext, ct->ext->len); | |
97 | ||
98 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
99 | if (!nf_ct_ext_exist(ct, i)) | |
100 | continue; | |
101 | ||
102 | rcu_read_lock(); | |
103 | t = rcu_dereference(nf_ct_ext_types[i]); | |
104 | if (t && t->move) | |
86577c66 PM |
105 | t->move((void *)new + new->offset[i], |
106 | (void *)ct->ext + ct->ext->offset[i]); | |
ecfab2c9 YK |
107 | rcu_read_unlock(); |
108 | } | |
109 | kfree(ct->ext); | |
ecfab2c9 YK |
110 | ct->ext = new; |
111 | } | |
112 | ||
113 | ct->ext->offset[id] = newoff; | |
114 | ct->ext->len = newlen; | |
115 | memset((void *)ct->ext + newoff, 0, newlen - newoff); | |
116 | return (void *)ct->ext + newoff; | |
117 | } | |
118 | EXPORT_SYMBOL(__nf_ct_ext_add); | |
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++) { | |
135 | t1 = nf_ct_ext_types[i]; | |
136 | if (!t1) | |
137 | continue; | |
138 | ||
139 | t1->alloc_size = sizeof(struct nf_ct_ext) | |
140 | + ALIGN(sizeof(struct nf_ct_ext), t1->align) | |
141 | + t1->len; | |
142 | for (j = 0; j < NF_CT_EXT_NUM; j++) { | |
143 | t2 = nf_ct_ext_types[j]; | |
144 | if (t2 == NULL || t2 == t1 || | |
145 | (t2->flags & NF_CT_EXT_F_PREALLOC) == 0) | |
146 | continue; | |
147 | ||
148 | t1->alloc_size = ALIGN(t1->alloc_size, t2->align) | |
149 | + t2->len; | |
150 | } | |
ecfab2c9 YK |
151 | } |
152 | } | |
153 | ||
154 | /* This MUST be called in process context. */ | |
155 | int nf_ct_extend_register(struct nf_ct_ext_type *type) | |
156 | { | |
157 | int ret = 0; | |
158 | ||
159 | mutex_lock(&nf_ct_ext_type_mutex); | |
160 | if (nf_ct_ext_types[type->id]) { | |
161 | ret = -EBUSY; | |
162 | goto out; | |
163 | } | |
164 | ||
165 | /* This ensures that nf_ct_ext_create() can allocate enough area | |
166 | before updating alloc_size */ | |
167 | type->alloc_size = ALIGN(sizeof(struct nf_ct_ext), type->align) | |
168 | + type->len; | |
169 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); | |
170 | update_alloc_size(type); | |
171 | out: | |
172 | mutex_unlock(&nf_ct_ext_type_mutex); | |
173 | return ret; | |
174 | } | |
175 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
176 | ||
177 | /* This MUST be called in process context. */ | |
178 | void nf_ct_extend_unregister(struct nf_ct_ext_type *type) | |
179 | { | |
180 | mutex_lock(&nf_ct_ext_type_mutex); | |
181 | rcu_assign_pointer(nf_ct_ext_types[type->id], NULL); | |
182 | update_alloc_size(type); | |
183 | mutex_unlock(&nf_ct_ext_type_mutex); | |
184 | synchronize_rcu(); | |
185 | } | |
186 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |