Commit | Line | Data |
---|---|---|
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> | |
7e5d03bb MJ |
18 | #include <linux/random.h> |
19 | #include <linux/err.h> | |
20 | #include <linux/kernel.h> | |
21 | #include <linux/netdevice.h> | |
2ba4cc31 | 22 | #include <linux/rculist.h> |
efb9a8c2 | 23 | #include <linux/rtnetlink.h> |
7e5d03bb | 24 | |
7e5d03bb MJ |
25 | #include <net/netfilter/nf_conntrack.h> |
26 | #include <net/netfilter/nf_conntrack_l3proto.h> | |
605dcad6 | 27 | #include <net/netfilter/nf_conntrack_l4proto.h> |
7e5d03bb MJ |
28 | #include <net/netfilter/nf_conntrack_helper.h> |
29 | #include <net/netfilter/nf_conntrack_core.h> | |
ceceae1b | 30 | #include <net/netfilter/nf_conntrack_extend.h> |
7e5d03bb | 31 | |
58a3c9bb | 32 | static DEFINE_MUTEX(nf_ct_helper_mutex); |
b8a7fe6c PM |
33 | static struct hlist_head *nf_ct_helper_hash __read_mostly; |
34 | static unsigned int nf_ct_helper_hsize __read_mostly; | |
35 | static unsigned int nf_ct_helper_count __read_mostly; | |
b8a7fe6c PM |
36 | |
37 | ||
38 | /* Stupid hash, but collision free for the default registrations of the | |
39 | * helpers currently in the kernel. */ | |
40 | static unsigned int helper_hash(const struct nf_conntrack_tuple *tuple) | |
41 | { | |
42 | return (((tuple->src.l3num << 8) | tuple->dst.protonum) ^ | |
a34c4589 | 43 | (__force __u16)tuple->src.u.all) % nf_ct_helper_hsize; |
b8a7fe6c | 44 | } |
7e5d03bb | 45 | |
226c0c0e | 46 | static struct nf_conntrack_helper * |
7e5d03bb MJ |
47 | __nf_ct_helper_find(const struct nf_conntrack_tuple *tuple) |
48 | { | |
b8a7fe6c | 49 | struct nf_conntrack_helper *helper; |
d4156e8c | 50 | struct nf_conntrack_tuple_mask mask = { .src.u.all = htons(0xFFFF) }; |
b8a7fe6c PM |
51 | struct hlist_node *n; |
52 | unsigned int h; | |
7e5d03bb | 53 | |
b8a7fe6c PM |
54 | if (!nf_ct_helper_count) |
55 | return NULL; | |
56 | ||
57 | h = helper_hash(tuple); | |
58a3c9bb | 58 | hlist_for_each_entry_rcu(helper, n, &nf_ct_helper_hash[h], hnode) { |
b8a7fe6c PM |
59 | if (nf_ct_tuple_src_mask_cmp(tuple, &helper->tuple, &mask)) |
60 | return helper; | |
7e5d03bb MJ |
61 | } |
62 | return NULL; | |
63 | } | |
7e5d03bb MJ |
64 | |
65 | struct nf_conntrack_helper * | |
794e6871 | 66 | __nf_conntrack_helper_find(const char *name, u16 l3num, u8 protonum) |
7e5d03bb MJ |
67 | { |
68 | struct nf_conntrack_helper *h; | |
b8a7fe6c PM |
69 | struct hlist_node *n; |
70 | unsigned int i; | |
7e5d03bb | 71 | |
b8a7fe6c | 72 | for (i = 0; i < nf_ct_helper_hsize; i++) { |
58a3c9bb | 73 | hlist_for_each_entry_rcu(h, n, &nf_ct_helper_hash[i], hnode) { |
794e6871 PM |
74 | if (!strcmp(h->name, name) && |
75 | h->tuple.src.l3num == l3num && | |
76 | h->tuple.dst.protonum == protonum) | |
b8a7fe6c PM |
77 | return h; |
78 | } | |
7e5d03bb | 79 | } |
7e5d03bb MJ |
80 | return NULL; |
81 | } | |
794e6871 | 82 | EXPORT_SYMBOL_GPL(__nf_conntrack_helper_find); |
7e5d03bb | 83 | |
84f3bb9a PM |
84 | struct nf_conntrack_helper * |
85 | nf_conntrack_helper_try_module_get(const char *name, u16 l3num, u8 protonum) | |
86 | { | |
87 | struct nf_conntrack_helper *h; | |
88 | ||
89 | h = __nf_conntrack_helper_find(name, l3num, protonum); | |
90 | #ifdef CONFIG_MODULES | |
91 | if (h == NULL) { | |
92 | if (request_module("nfct-helper-%s", name) == 0) | |
93 | h = __nf_conntrack_helper_find(name, l3num, protonum); | |
94 | } | |
95 | #endif | |
96 | if (h != NULL && !try_module_get(h->me)) | |
97 | h = NULL; | |
98 | ||
99 | return h; | |
100 | } | |
101 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_try_module_get); | |
102 | ||
b560580a PM |
103 | struct nf_conn_help *nf_ct_helper_ext_add(struct nf_conn *ct, gfp_t gfp) |
104 | { | |
105 | struct nf_conn_help *help; | |
106 | ||
107 | help = nf_ct_ext_add(ct, NF_CT_EXT_HELPER, gfp); | |
108 | if (help) | |
109 | INIT_HLIST_HEAD(&help->expectations); | |
110 | else | |
111 | pr_debug("failed to add helper extension area"); | |
112 | return help; | |
113 | } | |
114 | EXPORT_SYMBOL_GPL(nf_ct_helper_ext_add); | |
115 | ||
b2a15a60 PM |
116 | int __nf_ct_try_assign_helper(struct nf_conn *ct, struct nf_conn *tmpl, |
117 | gfp_t flags) | |
226c0c0e | 118 | { |
b2a15a60 PM |
119 | struct nf_conntrack_helper *helper = NULL; |
120 | struct nf_conn_help *help; | |
226c0c0e | 121 | int ret = 0; |
226c0c0e | 122 | |
b2a15a60 PM |
123 | if (tmpl != NULL) { |
124 | help = nfct_help(tmpl); | |
125 | if (help != NULL) | |
126 | helper = help->helper; | |
127 | } | |
128 | ||
129 | help = nfct_help(ct); | |
130 | if (helper == NULL) | |
131 | helper = __nf_ct_helper_find(&ct->tuplehash[IP_CT_DIR_REPLY].tuple); | |
226c0c0e PNA |
132 | if (helper == NULL) { |
133 | if (help) | |
a9b3cd7f | 134 | RCU_INIT_POINTER(help->helper, NULL); |
226c0c0e PNA |
135 | goto out; |
136 | } | |
137 | ||
138 | if (help == NULL) { | |
139 | help = nf_ct_helper_ext_add(ct, flags); | |
140 | if (help == NULL) { | |
141 | ret = -ENOMEM; | |
142 | goto out; | |
143 | } | |
144 | } else { | |
145 | memset(&help->help, 0, sizeof(help->help)); | |
146 | } | |
147 | ||
cf778b00 | 148 | rcu_assign_pointer(help->helper, helper); |
226c0c0e PNA |
149 | out: |
150 | return ret; | |
151 | } | |
152 | EXPORT_SYMBOL_GPL(__nf_ct_try_assign_helper); | |
153 | ||
7e5d03bb MJ |
154 | static inline int unhelp(struct nf_conntrack_tuple_hash *i, |
155 | const struct nf_conntrack_helper *me) | |
156 | { | |
157 | struct nf_conn *ct = nf_ct_tuplehash_to_ctrack(i); | |
158 | struct nf_conn_help *help = nfct_help(ct); | |
159 | ||
c5d277d2 ED |
160 | if (help && rcu_dereference_protected( |
161 | help->helper, | |
162 | lockdep_is_held(&nf_conntrack_lock) | |
163 | ) == me) { | |
7e5d03bb | 164 | nf_conntrack_event(IPCT_HELPER, ct); |
a9b3cd7f | 165 | RCU_INIT_POINTER(help->helper, NULL); |
7e5d03bb MJ |
166 | } |
167 | return 0; | |
168 | } | |
169 | ||
9858a3ae PNA |
170 | void nf_ct_helper_destroy(struct nf_conn *ct) |
171 | { | |
172 | struct nf_conn_help *help = nfct_help(ct); | |
173 | struct nf_conntrack_helper *helper; | |
174 | ||
175 | if (help) { | |
176 | rcu_read_lock(); | |
177 | helper = rcu_dereference(help->helper); | |
178 | if (helper && helper->destroy) | |
179 | helper->destroy(ct); | |
180 | rcu_read_unlock(); | |
181 | } | |
182 | } | |
183 | ||
544d5c7d PNA |
184 | static LIST_HEAD(nf_ct_helper_expectfn_list); |
185 | ||
186 | void nf_ct_helper_expectfn_register(struct nf_ct_helper_expectfn *n) | |
187 | { | |
188 | spin_lock_bh(&nf_conntrack_lock); | |
189 | list_add_rcu(&n->head, &nf_ct_helper_expectfn_list); | |
190 | spin_unlock_bh(&nf_conntrack_lock); | |
191 | } | |
192 | EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_register); | |
193 | ||
194 | void nf_ct_helper_expectfn_unregister(struct nf_ct_helper_expectfn *n) | |
195 | { | |
196 | spin_lock_bh(&nf_conntrack_lock); | |
197 | list_del_rcu(&n->head); | |
198 | spin_unlock_bh(&nf_conntrack_lock); | |
199 | } | |
200 | EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_unregister); | |
201 | ||
202 | struct nf_ct_helper_expectfn * | |
203 | nf_ct_helper_expectfn_find_by_name(const char *name) | |
204 | { | |
205 | struct nf_ct_helper_expectfn *cur; | |
206 | bool found = false; | |
207 | ||
208 | rcu_read_lock(); | |
209 | list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { | |
210 | if (!strcmp(cur->name, name)) { | |
211 | found = true; | |
212 | break; | |
213 | } | |
214 | } | |
215 | rcu_read_unlock(); | |
216 | return found ? cur : NULL; | |
217 | } | |
218 | EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_name); | |
219 | ||
220 | struct nf_ct_helper_expectfn * | |
221 | nf_ct_helper_expectfn_find_by_symbol(const void *symbol) | |
222 | { | |
223 | struct nf_ct_helper_expectfn *cur; | |
224 | bool found = false; | |
225 | ||
226 | rcu_read_lock(); | |
227 | list_for_each_entry_rcu(cur, &nf_ct_helper_expectfn_list, head) { | |
228 | if (cur->expectfn == symbol) { | |
229 | found = true; | |
230 | break; | |
231 | } | |
232 | } | |
233 | rcu_read_unlock(); | |
234 | return found ? cur : NULL; | |
235 | } | |
236 | EXPORT_SYMBOL_GPL(nf_ct_helper_expectfn_find_by_symbol); | |
237 | ||
7e5d03bb MJ |
238 | int nf_conntrack_helper_register(struct nf_conntrack_helper *me) |
239 | { | |
b8a7fe6c PM |
240 | unsigned int h = helper_hash(&me->tuple); |
241 | ||
6002f266 PM |
242 | BUG_ON(me->expect_policy == NULL); |
243 | BUG_ON(me->expect_class_max >= NF_CT_MAX_EXPECT_CLASSES); | |
af9d32ad | 244 | BUG_ON(strlen(me->name) > NF_CT_HELPER_NAME_LEN - 1); |
7e5d03bb | 245 | |
58a3c9bb PM |
246 | mutex_lock(&nf_ct_helper_mutex); |
247 | hlist_add_head_rcu(&me->hnode, &nf_ct_helper_hash[h]); | |
b8a7fe6c | 248 | nf_ct_helper_count++; |
58a3c9bb | 249 | mutex_unlock(&nf_ct_helper_mutex); |
7e5d03bb MJ |
250 | |
251 | return 0; | |
252 | } | |
13b18339 | 253 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_register); |
7e5d03bb | 254 | |
68047937 AD |
255 | static void __nf_conntrack_helper_unregister(struct nf_conntrack_helper *me, |
256 | struct net *net) | |
7e5d03bb | 257 | { |
7e5d03bb | 258 | struct nf_conntrack_tuple_hash *h; |
31f15875 | 259 | struct nf_conntrack_expect *exp; |
58c0fb0d | 260 | const struct hlist_node *n, *next; |
ea781f19 | 261 | const struct hlist_nulls_node *nn; |
31f15875 | 262 | unsigned int i; |
7e5d03bb | 263 | |
7e5d03bb | 264 | /* Get rid of expectations */ |
31f15875 PM |
265 | for (i = 0; i < nf_ct_expect_hsize; i++) { |
266 | hlist_for_each_entry_safe(exp, n, next, | |
68047937 | 267 | &net->ct.expect_hash[i], hnode) { |
31f15875 | 268 | struct nf_conn_help *help = nfct_help(exp->master); |
c5d277d2 ED |
269 | if ((rcu_dereference_protected( |
270 | help->helper, | |
271 | lockdep_is_held(&nf_conntrack_lock) | |
272 | ) == me || exp->helper == me) && | |
31f15875 PM |
273 | del_timer(&exp->timeout)) { |
274 | nf_ct_unlink_expect(exp); | |
275 | nf_ct_expect_put(exp); | |
276 | } | |
7e5d03bb MJ |
277 | } |
278 | } | |
279 | ||
280 | /* Get rid of expecteds, set helpers to NULL. */ | |
38fb0afc | 281 | hlist_nulls_for_each_entry(h, nn, &net->ct.unconfirmed, hnnode) |
7e5d03bb | 282 | unhelp(h, me); |
d696c7bd | 283 | for (i = 0; i < net->ct.htable_size; i++) { |
ea781f19 | 284 | hlist_nulls_for_each_entry(h, nn, &net->ct.hash[i], hnnode) |
7e5d03bb MJ |
285 | unhelp(h, me); |
286 | } | |
68047937 AD |
287 | } |
288 | ||
289 | void nf_conntrack_helper_unregister(struct nf_conntrack_helper *me) | |
290 | { | |
291 | struct net *net; | |
292 | ||
293 | mutex_lock(&nf_ct_helper_mutex); | |
294 | hlist_del_rcu(&me->hnode); | |
295 | nf_ct_helper_count--; | |
296 | mutex_unlock(&nf_ct_helper_mutex); | |
297 | ||
298 | /* Make sure every nothing is still using the helper unless its a | |
299 | * connection in the hash. | |
300 | */ | |
301 | synchronize_rcu(); | |
302 | ||
efb9a8c2 | 303 | rtnl_lock(); |
68047937 AD |
304 | spin_lock_bh(&nf_conntrack_lock); |
305 | for_each_net(net) | |
306 | __nf_conntrack_helper_unregister(me, net); | |
f8ba1aff | 307 | spin_unlock_bh(&nf_conntrack_lock); |
efb9a8c2 | 308 | rtnl_unlock(); |
7e5d03bb | 309 | } |
13b18339 | 310 | EXPORT_SYMBOL_GPL(nf_conntrack_helper_unregister); |
ceceae1b | 311 | |
61eb3107 | 312 | static struct nf_ct_ext_type helper_extend __read_mostly = { |
ceceae1b YK |
313 | .len = sizeof(struct nf_conn_help), |
314 | .align = __alignof__(struct nf_conn_help), | |
315 | .id = NF_CT_EXT_HELPER, | |
316 | }; | |
317 | ||
8d4bc5b6 | 318 | int nf_conntrack_helper_init(void) |
ceceae1b | 319 | { |
b8a7fe6c PM |
320 | int err; |
321 | ||
322 | nf_ct_helper_hsize = 1; /* gets rounded up to use one page */ | |
d862a662 | 323 | nf_ct_helper_hash = nf_ct_alloc_hashtable(&nf_ct_helper_hsize, 0); |
b8a7fe6c PM |
324 | if (!nf_ct_helper_hash) |
325 | return -ENOMEM; | |
326 | ||
327 | err = nf_ct_extend_register(&helper_extend); | |
328 | if (err < 0) | |
329 | goto err1; | |
330 | ||
331 | return 0; | |
332 | ||
333 | err1: | |
d862a662 | 334 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_hsize); |
b8a7fe6c | 335 | return err; |
ceceae1b YK |
336 | } |
337 | ||
8d4bc5b6 | 338 | void nf_conntrack_helper_fini(void) |
ceceae1b YK |
339 | { |
340 | nf_ct_extend_unregister(&helper_extend); | |
d862a662 | 341 | nf_ct_free_hashtable(nf_ct_helper_hash, nf_ct_helper_hsize); |
ceceae1b | 342 | } |