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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 | 20 | static DEFINE_MUTEX(nf_ct_ext_type_mutex); |
54044b1f | 21 | #define NF_CT_EXT_PREALLOC 128u /* conntrack events are on by default */ |
ecfab2c9 | 22 | |
ecfab2c9 YK |
23 | void __nf_ct_ext_destroy(struct nf_conn *ct) |
24 | { | |
25 | unsigned int i; | |
26 | struct nf_ct_ext_type *t; | |
ee92d378 | 27 | struct nf_ct_ext *ext = ct->ext; |
ecfab2c9 YK |
28 | |
29 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
ee92d378 | 30 | if (!__nf_ct_ext_exist(ext, i)) |
ecfab2c9 YK |
31 | continue; |
32 | ||
33 | rcu_read_lock(); | |
34 | t = rcu_dereference(nf_ct_ext_types[i]); | |
35 | ||
36 | /* Here the nf_ct_ext_type might have been unregisterd. | |
37 | * I.e., it has responsible to cleanup private | |
38 | * area in all conntracks when it is unregisterd. | |
39 | */ | |
40 | if (t && t->destroy) | |
41 | t->destroy(ct); | |
42 | rcu_read_unlock(); | |
43 | } | |
44 | } | |
45 | EXPORT_SYMBOL(__nf_ct_ext_destroy); | |
46 | ||
47 | static void * | |
faec865d | 48 | nf_ct_ext_create(struct nf_ct_ext **ext, enum nf_ct_ext_id id, gfp_t gfp) |
ecfab2c9 | 49 | { |
54044b1f | 50 | unsigned int off, len, alloc; |
ecfab2c9 YK |
51 | struct nf_ct_ext_type *t; |
52 | ||
53 | rcu_read_lock(); | |
54 | t = rcu_dereference(nf_ct_ext_types[id]); | |
9c3f3794 LZ |
55 | if (!t) { |
56 | rcu_read_unlock(); | |
57 | return NULL; | |
58 | } | |
59 | ||
ecfab2c9 | 60 | off = ALIGN(sizeof(struct nf_ct_ext), t->align); |
faec865d | 61 | len = off + t->len; |
ecfab2c9 YK |
62 | rcu_read_unlock(); |
63 | ||
54044b1f FW |
64 | alloc = max(len, NF_CT_EXT_PREALLOC); |
65 | *ext = kzalloc(alloc, gfp); | |
ecfab2c9 YK |
66 | if (!*ext) |
67 | return NULL; | |
68 | ||
69 | (*ext)->offset[id] = off; | |
70 | (*ext)->len = len; | |
ecfab2c9 YK |
71 | |
72 | return (void *)(*ext) + off; | |
73 | } | |
74 | ||
faec865d | 75 | void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) |
ecfab2c9 | 76 | { |
ee92d378 | 77 | struct nf_ct_ext *old, *new; |
7c966435 | 78 | int newlen, newoff; |
ecfab2c9 YK |
79 | struct nf_ct_ext_type *t; |
80 | ||
55871d04 PM |
81 | /* Conntrack must not be confirmed to avoid races on reallocation. */ |
82 | NF_CT_ASSERT(!nf_ct_is_confirmed(ct)); | |
83 | ||
ee92d378 CG |
84 | old = ct->ext; |
85 | if (!old) | |
faec865d | 86 | return nf_ct_ext_create(&ct->ext, id, gfp); |
ecfab2c9 | 87 | |
ee92d378 | 88 | if (__nf_ct_ext_exist(old, id)) |
ecfab2c9 YK |
89 | return NULL; |
90 | ||
91 | rcu_read_lock(); | |
92 | t = rcu_dereference(nf_ct_ext_types[id]); | |
9c3f3794 LZ |
93 | if (!t) { |
94 | rcu_read_unlock(); | |
95 | return NULL; | |
96 | } | |
ecfab2c9 | 97 | |
ee92d378 | 98 | newoff = ALIGN(old->len, t->align); |
faec865d | 99 | newlen = newoff + t->len; |
ecfab2c9 YK |
100 | rcu_read_unlock(); |
101 | ||
ee92d378 | 102 | new = __krealloc(old, newlen, gfp); |
31d8519c PE |
103 | if (!new) |
104 | return NULL; | |
ecfab2c9 | 105 | |
ee92d378 | 106 | if (new != old) { |
1f8d36a1 | 107 | kfree_rcu(old, rcu); |
7c966435 | 108 | rcu_assign_pointer(ct->ext, new); |
ecfab2c9 YK |
109 | } |
110 | ||
6c64825b PM |
111 | new->offset[id] = newoff; |
112 | new->len = newlen; | |
113 | memset((void *)new + newoff, 0, newlen - newoff); | |
114 | return (void *)new + newoff; | |
ecfab2c9 | 115 | } |
faec865d | 116 | EXPORT_SYMBOL(nf_ct_ext_add); |
ecfab2c9 | 117 | |
ecfab2c9 | 118 | /* This MUST be called in process context. */ |
23f671a1 | 119 | int nf_ct_extend_register(const struct nf_ct_ext_type *type) |
ecfab2c9 YK |
120 | { |
121 | int ret = 0; | |
122 | ||
123 | mutex_lock(&nf_ct_ext_type_mutex); | |
124 | if (nf_ct_ext_types[type->id]) { | |
125 | ret = -EBUSY; | |
126 | goto out; | |
127 | } | |
128 | ||
cf778b00 | 129 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); |
ecfab2c9 YK |
130 | out: |
131 | mutex_unlock(&nf_ct_ext_type_mutex); | |
132 | return ret; | |
133 | } | |
134 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
135 | ||
136 | /* This MUST be called in process context. */ | |
23f671a1 | 137 | void nf_ct_extend_unregister(const struct nf_ct_ext_type *type) |
ecfab2c9 YK |
138 | { |
139 | mutex_lock(&nf_ct_ext_type_mutex); | |
a9b3cd7f | 140 | RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL); |
ecfab2c9 | 141 | mutex_unlock(&nf_ct_ext_type_mutex); |
9c3f3794 | 142 | synchronize_rcu(); |
ecfab2c9 YK |
143 | } |
144 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |