Commit | Line | Data |
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7e5d03bb MJ |
1 | /* Helper handling for netfilter. */ |
2 | ||
3 | /* (C) 1999-2001 Paul `Rusty' Russell | |
4 | * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org> | |
5 | * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org> | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or modify | |
8 | * it under the terms of the GNU General Public License version 2 as | |
9 | * published by the Free Software Foundation. | |
10 | */ | |
11 | ||
12 | #include <linux/types.h> | |
13 | #include <linux/netfilter.h> | |
14 | #include <linux/module.h> | |
15 | #include <linux/skbuff.h> | |
16 | #include <linux/vmalloc.h> | |
17 | #include <linux/stddef.h> | |
18 | #include <linux/slab.h> | |
19 | #include <linux/random.h> | |
20 | #include <linux/err.h> | |
21 | #include <linux/kernel.h> | |
22 | #include <linux/netdevice.h> | |
2ba4cc31 | 23 | #include <linux/rculist.h> |
efb9a8c2 | 24 | #include <linux/rtnetlink.h> |
7e5d03bb | 25 | |
7e5d03bb MJ |
26 | #include <net/netfilter/nf_conntrack.h> |
27 | #include <net/netfilter/nf_conntrack_l3proto.h> | |
605dcad6 | 28 | #include <net/netfilter/nf_conntrack_l4proto.h> |
7e5d03bb MJ |
29 | #include <net/netfilter/nf_conntrack_helper.h> |
30 | #include <net/netfilter/nf_conntrack_core.h> | |
ceceae1b | 31 | #include <net/netfilter/nf_conntrack_extend.h> |
7e5d03bb | 32 | |
58a3c9bb | 33 | static DEFINE_MUTEX(nf_ct_helper_mutex); |
b8a7fe6c PM |
34 | static struct hlist_head *nf_ct_helper_hash __read_mostly; |
35 | static unsigned int nf_ct_helper_hsize __read_mostly; | |
36 | static unsigned int nf_ct_helper_count __read_mostly; | |
37 | static int nf_ct_helper_vmalloc; | |
38 | ||
39 | ||
40 | /* Stupid hash, but collision free for the default registrations of the | |
41 | * helpers currently in the kernel. */ | |
42 | static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple) | |
43 | { | |
44 | return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^ | |
a34c4589 | 45 | (__force __u16)tuple->src.u.all) % nf_ct_helper_hsize; |
b8a7fe6c | 46 | } |
7e5d03bb | 47 | |
226c0c0e | 48 | static struct nf_conntrack_helper * |
7e5d03bb MJ |
49 | __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple) |
50 | { | |
b8a7fe6c | 51 | struct nf_conntrack_helper *helper; |
d4156e8c | 52 | struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) }; |
b8a7fe6c PM |
53 | struct hlist_node *n; |
54 | unsigned int h; | |
7e5d03bb | 55 | |
b8a7fe6c PM |
56 | if (!nf_ct_helper_count) |
57 | return NULL; | |
58 | ||
59 | h = helper_hash(tuple); | |
58a3c9bb | 60 | hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) { |
b8a7fe6c PM |
61 | if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask)) |
62 | return helper; | |
7e5d03bb MJ |
63 | } |
64 | return NULL; | |
65 | } | |
7e5d03bb MJ |
66 | |
67 | struct nf_conntrack_helper * | |
68 | __nf_conntrack_helper_find_byname(const char *name) | |
69 | { | |
70 | struct nf_conntrack_helper *h; | |
b8a7fe6c PM |
71 | struct hlist_node *n; |
72 | unsigned int i; | |
7e5d03bb | 73 | |
b8a7fe6c | 74 | for (i = 0; i < nf_ct_helper_hsize; i++) { |
58a3c9bb | 75 | hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) { |
b8a7fe6c PM |
76 | if (!strcmp(h->name, name)) |
77 | return h; | |
78 | } | |
7e5d03bb | 79 | } |
7e5d03bb MJ |
80 | return NULL; |
81 | } | |
13b18339 | 82 | EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find_byname); |
7e5d03bb | 83 | |
b560580a PM |
84 | struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp) |
85 | { | |
86 | struct nf_conn_help *help; | |
87 | ||
88 | help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp); | |
89 | if (help) | |
90 | INIT_HLIST_HEAD(&help->expectations); | |
91 | else | |
92 | pr_debug("failed to add helper extension area"); | |
93 | return help; | |
94 | } | |
95 | EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add); | |
96 | ||
226c0c0e PNA |
97 | int __nf_ct_try_assign_helper(struct nf_conn *ct, gfp_t flags) |
98 | { | |
99 | int ret = 0; | |
100 | struct nf_conntrack_helper *helper; | |
101 | struct nf_conn_help *help = nfct_help(ct); | |
102 | ||
103 | helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
104 | if (helper == NULL) { | |
105 | if (help) | |
106 | rcu_assign_pointer(help->helper, NULL); | |
107 | goto out; | |
108 | } | |
109 | ||
110 | if (help == NULL) { | |
111 | help = nf_ct_helper_ext_add(ct, flags); | |
112 | if (help == NULL) { | |
113 | ret = -ENOMEM; | |
114 | goto out; | |
115 | } | |
116 | } else { | |
117 | memset(&help->help, 0, sizeof(help->help)); | |
118 | } | |
119 | ||
120 | rcu_assign_pointer(help->helper, helper); | |
121 | out: | |
122 | return ret; | |
123 | } | |
124 | EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper); | |
125 | ||
7e5d03bb MJ |
126 | static inline int unhelp(struct nf_conntrack_tuple_hash *i, |
127 | const struct nf_conntrack_helper *me) | |
128 | { | |
129 | struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i); | |
130 | struct nf_conn_help *help = nfct_help(ct); | |
131 | ||
132 | if (help && help->helper == me) { | |
133 | nf_conntrack_event(IPCT_HELPER, ct); | |
3c158f7f | 134 | rcu_assign_pointer(help->helper, NULL); |
7e5d03bb MJ |
135 | } |
136 | return 0; | |
137 | } | |
138 | ||
139 | int nf_conntrack_helper_register(struct nf_conntrack_helper *me) | |
140 | { | |
b8a7fe6c PM |
141 | unsigned int h = helper_hash(&me->tuple); |
142 | ||
6002f266 PM |
143 | BUG_ON(me->expect_policy == NULL); |
144 | BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES); | |
af9d32ad | 145 | BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1); |
7e5d03bb | 146 | |
58a3c9bb PM |
147 | mutex_lock(&nf_ct_helper_mutex); |
148 | hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]); | |
b8a7fe6c | 149 | nf_ct_helper_count++; |
58a3c9bb | 150 | mutex_unlock(&nf_ct_helper_mutex); |
7e5d03bb MJ |
151 | |
152 | return 0; | |
153 | } | |
13b18339 | 154 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_register); |
7e5d03bb | 155 | |
68047937 AD |
156 | static void __nf_conntrack_helper_unregister(struct nf_conntrack_helper *me, |
157 | struct net *net) | |
7e5d03bb | 158 | { |
7e5d03bb | 159 | struct nf_conntrack_tuple_hash *h; |
31f15875 | 160 | struct nf_conntrack_expect *exp; |
58c0fb0d | 161 | const struct hlist_node *n, *next; |
ea781f19 | 162 | const struct hlist_nulls_node *nn; |
31f15875 | 163 | unsigned int i; |
7e5d03bb | 164 | |
7e5d03bb | 165 | /* Get rid of expectations */ |
31f15875 PM |
166 | for (i = 0; i < nf_ct_expect_hsize; i++) { |
167 | hlist_for_each_entry_safe(exp, n, next, | |
68047937 | 168 | &net->ct.expect_hash[i], hnode) { |
31f15875 PM |
169 | struct nf_conn_help *help = nfct_help(exp->master); |
170 | if ((help->helper == me || exp->helper == me) && | |
171 | del_timer(&exp->timeout)) { | |
172 | nf_ct_unlink_expect(exp); | |
173 | nf_ct_expect_put(exp); | |
174 | } | |
7e5d03bb MJ |
175 | } |
176 | } | |
177 | ||
178 | /* Get rid of expecteds, set helpers to NULL. */ | |
38fb0afc | 179 | hlist_nulls_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode) |
7e5d03bb MJ |
180 | unhelp(h, me); |
181 | for (i = 0; i < nf_conntrack_htable_size; i++) { | |
ea781f19 | 182 | hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode) |
7e5d03bb MJ |
183 | unhelp(h, me); |
184 | } | |
68047937 AD |
185 | } |
186 | ||
187 | void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) | |
188 | { | |
189 | struct net *net; | |
190 | ||
191 | mutex_lock(&nf_ct_helper_mutex); | |
192 | hlist_del_rcu(&me->hnode); | |
193 | nf_ct_helper_count--; | |
194 | mutex_unlock(&nf_ct_helper_mutex); | |
195 | ||
196 | /* Make sure every nothing is still using the helper unless its a | |
197 | * connection in the hash. | |
198 | */ | |
199 | synchronize_rcu(); | |
200 | ||
efb9a8c2 | 201 | rtnl_lock(); |
68047937 AD |
202 | spin_lock_bh(&nf_conntrack_lock); |
203 | for_each_net(net) | |
204 | __nf_conntrack_helper_unregister(me, net); | |
f8ba1aff | 205 | spin_unlock_bh(&nf_conntrack_lock); |
efb9a8c2 | 206 | rtnl_unlock(); |
7e5d03bb | 207 | } |
13b18339 | 208 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); |
ceceae1b | 209 | |
61eb3107 | 210 | static struct nf_ct_ext_type helper_extend __read_mostly = { |
ceceae1b YK |
211 | .len = sizeof(struct nf_conn_help), |
212 | .align = __alignof__(struct nf_conn_help), | |
213 | .id = NF_CT_EXT_HELPER, | |
214 | }; | |
215 | ||
8d4bc5b6 | 216 | int nf_conntrack_helper_init(void) |
ceceae1b | 217 | { |
b8a7fe6c PM |
218 | int err; |
219 | ||
220 | nf_ct_helper_hsize = 1; /* gets rounded up to use one page */ | |
221 | nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize, | |
ea781f19 | 222 | &nf_ct_helper_vmalloc, 0); |
b8a7fe6c PM |
223 | if (!nf_ct_helper_hash) |
224 | return -ENOMEM; | |
225 | ||
226 | err = nf_ct_extend_register(&helper_extend); | |
227 | if (err < 0) | |
228 | goto err1; | |
229 | ||
230 | return 0; | |
231 | ||
232 | err1: | |
233 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc, | |
234 | nf_ct_helper_hsize); | |
235 | return err; | |
ceceae1b YK |
236 | } |
237 | ||
8d4bc5b6 | 238 | void nf_conntrack_helper_fini(void) |
ceceae1b YK |
239 | { |
240 | nf_ct_extend_unregister(&helper_extend); | |
b8a7fe6c PM |
241 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_vmalloc, |
242 | nf_ct_helper_hsize); | |
ceceae1b | 243 | } |