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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 | |
8eeef235 | 23 | void nf_ct_ext_destroy(struct nf_conn *ct) |
ecfab2c9 YK |
24 | { |
25 | unsigned int i; | |
26 | struct nf_ct_ext_type *t; | |
27 | ||
28 | for (i = 0; i < NF_CT_EXT_NUM; i++) { | |
ecfab2c9 YK |
29 | rcu_read_lock(); |
30 | t = rcu_dereference(nf_ct_ext_types[i]); | |
31 | ||
32 | /* Here the nf_ct_ext_type might have been unregisterd. | |
33 | * I.e., it has responsible to cleanup private | |
34 | * area in all conntracks when it is unregisterd. | |
35 | */ | |
36 | if (t && t->destroy) | |
37 | t->destroy(ct); | |
38 | rcu_read_unlock(); | |
39 | } | |
40 | } | |
8eeef235 | 41 | EXPORT_SYMBOL(nf_ct_ext_destroy); |
ecfab2c9 | 42 | |
faec865d | 43 | void *nf_ct_ext_add(struct nf_conn *ct, enum nf_ct_ext_id id, gfp_t gfp) |
ecfab2c9 | 44 | { |
22d4536d | 45 | unsigned int newlen, newoff, oldlen, alloc; |
ee92d378 | 46 | struct nf_ct_ext *old, *new; |
ecfab2c9 YK |
47 | struct nf_ct_ext_type *t; |
48 | ||
55871d04 | 49 | /* Conntrack must not be confirmed to avoid races on reallocation. */ |
44d6e2f2 | 50 | WARN_ON(nf_ct_is_confirmed(ct)); |
55871d04 | 51 | |
ee92d378 | 52 | old = ct->ext; |
ecfab2c9 | 53 | |
22d4536d FW |
54 | if (old) { |
55 | if (__nf_ct_ext_exist(old, id)) | |
56 | return NULL; | |
57 | oldlen = old->len; | |
58 | } else { | |
59 | oldlen = sizeof(*new); | |
60 | } | |
ecfab2c9 YK |
61 | |
62 | rcu_read_lock(); | |
63 | t = rcu_dereference(nf_ct_ext_types[id]); | |
9c3f3794 LZ |
64 | if (!t) { |
65 | rcu_read_unlock(); | |
66 | return NULL; | |
67 | } | |
ecfab2c9 | 68 | |
22d4536d | 69 | newoff = ALIGN(oldlen, t->align); |
faec865d | 70 | newlen = newoff + t->len; |
ecfab2c9 YK |
71 | rcu_read_unlock(); |
72 | ||
22d4536d FW |
73 | alloc = max(newlen, NF_CT_EXT_PREALLOC); |
74 | new = __krealloc(old, alloc, gfp); | |
31d8519c PE |
75 | if (!new) |
76 | return NULL; | |
ecfab2c9 | 77 | |
22d4536d FW |
78 | if (!old) { |
79 | memset(new->offset, 0, sizeof(new->offset)); | |
80 | ct->ext = new; | |
81 | } else if (new != old) { | |
1f8d36a1 | 82 | kfree_rcu(old, rcu); |
7c966435 | 83 | rcu_assign_pointer(ct->ext, new); |
ecfab2c9 YK |
84 | } |
85 | ||
6c64825b PM |
86 | new->offset[id] = newoff; |
87 | new->len = newlen; | |
88 | memset((void *)new + newoff, 0, newlen - newoff); | |
89 | return (void *)new + newoff; | |
ecfab2c9 | 90 | } |
faec865d | 91 | EXPORT_SYMBOL(nf_ct_ext_add); |
ecfab2c9 | 92 | |
ecfab2c9 | 93 | /* This MUST be called in process context. */ |
23f671a1 | 94 | int nf_ct_extend_register(const struct nf_ct_ext_type *type) |
ecfab2c9 YK |
95 | { |
96 | int ret = 0; | |
97 | ||
98 | mutex_lock(&nf_ct_ext_type_mutex); | |
99 | if (nf_ct_ext_types[type->id]) { | |
100 | ret = -EBUSY; | |
101 | goto out; | |
102 | } | |
103 | ||
cf778b00 | 104 | rcu_assign_pointer(nf_ct_ext_types[type->id], type); |
ecfab2c9 YK |
105 | out: |
106 | mutex_unlock(&nf_ct_ext_type_mutex); | |
107 | return ret; | |
108 | } | |
109 | EXPORT_SYMBOL_GPL(nf_ct_extend_register); | |
110 | ||
111 | /* This MUST be called in process context. */ | |
23f671a1 | 112 | void nf_ct_extend_unregister(const struct nf_ct_ext_type *type) |
ecfab2c9 YK |
113 | { |
114 | mutex_lock(&nf_ct_ext_type_mutex); | |
a9b3cd7f | 115 | RCU_INIT_POINTER(nf_ct_ext_types[type->id], NULL); |
ecfab2c9 | 116 | mutex_unlock(&nf_ct_ext_type_mutex); |
9c3f3794 | 117 | synchronize_rcu(); |
ecfab2c9 YK |
118 | } |
119 | EXPORT_SYMBOL_GPL(nf_ct_extend_unregister); |