nf_conntrack_proto.c 9.8 KB

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  1. /* L3/L4 protocol support for nf_conntrack. */
  2. /* (C) 1999-2001 Paul `Rusty' Russell
  3. * (C) 2002-2006 Netfilter Core Team <coreteam@netfilter.org>
  4. * (C) 2003,2004 USAGI/WIDE Project <http://www.linux-ipv6.org>
  5. *
  6. * This program is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License version 2 as
  8. * published by the Free Software Foundation.
  9. */
  10. #include <linux/types.h>
  11. #include <linux/netfilter.h>
  12. #include <linux/module.h>
  13. #include <linux/mutex.h>
  14. #include <linux/skbuff.h>
  15. #include <linux/vmalloc.h>
  16. #include <linux/stddef.h>
  17. #include <linux/err.h>
  18. #include <linux/percpu.h>
  19. #include <linux/moduleparam.h>
  20. #include <linux/notifier.h>
  21. #include <linux/kernel.h>
  22. #include <linux/netdevice.h>
  23. #include <net/netfilter/nf_conntrack.h>
  24. #include <net/netfilter/nf_conntrack_l3proto.h>
  25. #include <net/netfilter/nf_conntrack_l4proto.h>
  26. #include <net/netfilter/nf_conntrack_core.h>
  27. struct nf_conntrack_l4proto **nf_ct_protos[PF_MAX] __read_mostly;
  28. struct nf_conntrack_l3proto *nf_ct_l3protos[AF_MAX] __read_mostly;
  29. EXPORT_SYMBOL_GPL(nf_ct_l3protos);
  30. #ifdef CONFIG_SYSCTL
  31. static DEFINE_MUTEX(nf_ct_proto_sysctl_mutex);
  32. static int
  33. nf_ct_register_sysctl(struct ctl_table_header **header, struct ctl_table *path,
  34. struct ctl_table *table, unsigned int *users)
  35. {
  36. if (*header == NULL) {
  37. *header = nf_register_sysctl_table(path, table);
  38. if (*header == NULL)
  39. return -ENOMEM;
  40. }
  41. if (users != NULL)
  42. (*users)++;
  43. return 0;
  44. }
  45. static void
  46. nf_ct_unregister_sysctl(struct ctl_table_header **header,
  47. struct ctl_table *table, unsigned int *users)
  48. {
  49. if (users != NULL && --*users > 0)
  50. return;
  51. nf_unregister_sysctl_table(*header, table);
  52. *header = NULL;
  53. }
  54. #endif
  55. struct nf_conntrack_l4proto *
  56. __nf_ct_l4proto_find(u_int16_t l3proto, u_int8_t l4proto)
  57. {
  58. if (unlikely(l3proto >= AF_MAX || nf_ct_protos[l3proto] == NULL))
  59. return &nf_conntrack_l4proto_generic;
  60. return rcu_dereference(nf_ct_protos[l3proto][l4proto]);
  61. }
  62. EXPORT_SYMBOL_GPL(__nf_ct_l4proto_find);
  63. /* this is guaranteed to always return a valid protocol helper, since
  64. * it falls back to generic_protocol */
  65. struct nf_conntrack_l4proto *
  66. nf_ct_l4proto_find_get(u_int16_t l3proto, u_int8_t l4proto)
  67. {
  68. struct nf_conntrack_l4proto *p;
  69. rcu_read_lock();
  70. p = __nf_ct_l4proto_find(l3proto, l4proto);
  71. if (!try_module_get(p->me))
  72. p = &nf_conntrack_l4proto_generic;
  73. rcu_read_unlock();
  74. return p;
  75. }
  76. EXPORT_SYMBOL_GPL(nf_ct_l4proto_find_get);
  77. void nf_ct_l4proto_put(struct nf_conntrack_l4proto *p)
  78. {
  79. module_put(p->me);
  80. }
  81. EXPORT_SYMBOL_GPL(nf_ct_l4proto_put);
  82. struct nf_conntrack_l3proto *
  83. nf_ct_l3proto_find_get(u_int16_t l3proto)
  84. {
  85. struct nf_conntrack_l3proto *p;
  86. rcu_read_lock();
  87. p = __nf_ct_l3proto_find(l3proto);
  88. if (!try_module_get(p->me))
  89. p = &nf_conntrack_l3proto_generic;
  90. rcu_read_unlock();
  91. return p;
  92. }
  93. EXPORT_SYMBOL_GPL(nf_ct_l3proto_find_get);
  94. void nf_ct_l3proto_put(struct nf_conntrack_l3proto *p)
  95. {
  96. module_put(p->me);
  97. }
  98. EXPORT_SYMBOL_GPL(nf_ct_l3proto_put);
  99. int
  100. nf_ct_l3proto_try_module_get(unsigned short l3proto)
  101. {
  102. int ret;
  103. struct nf_conntrack_l3proto *p;
  104. retry: p = nf_ct_l3proto_find_get(l3proto);
  105. if (p == &nf_conntrack_l3proto_generic) {
  106. ret = request_module("nf_conntrack-%d", l3proto);
  107. if (!ret)
  108. goto retry;
  109. return -EPROTOTYPE;
  110. }
  111. return 0;
  112. }
  113. EXPORT_SYMBOL_GPL(nf_ct_l3proto_try_module_get);
  114. void nf_ct_l3proto_module_put(unsigned short l3proto)
  115. {
  116. struct nf_conntrack_l3proto *p;
  117. /* rcu_read_lock not necessary since the caller holds a reference */
  118. p = __nf_ct_l3proto_find(l3proto);
  119. module_put(p->me);
  120. }
  121. EXPORT_SYMBOL_GPL(nf_ct_l3proto_module_put);
  122. static int kill_l3proto(struct nf_conn *i, void *data)
  123. {
  124. return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
  125. ((struct nf_conntrack_l3proto *)data)->l3proto);
  126. }
  127. static int kill_l4proto(struct nf_conn *i, void *data)
  128. {
  129. struct nf_conntrack_l4proto *l4proto;
  130. l4proto = (struct nf_conntrack_l4proto *)data;
  131. return (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.dst.protonum ==
  132. l4proto->l4proto) &&
  133. (i->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.l3num ==
  134. l4proto->l3proto);
  135. }
  136. static int nf_ct_l3proto_register_sysctl(struct nf_conntrack_l3proto *l3proto)
  137. {
  138. int err = 0;
  139. #ifdef CONFIG_SYSCTL
  140. mutex_lock(&nf_ct_proto_sysctl_mutex);
  141. if (l3proto->ctl_table != NULL) {
  142. err = nf_ct_register_sysctl(&l3proto->ctl_table_header,
  143. l3proto->ctl_table_path,
  144. l3proto->ctl_table, NULL);
  145. }
  146. mutex_unlock(&nf_ct_proto_sysctl_mutex);
  147. #endif
  148. return err;
  149. }
  150. static void nf_ct_l3proto_unregister_sysctl(struct nf_conntrack_l3proto *l3proto)
  151. {
  152. #ifdef CONFIG_SYSCTL
  153. mutex_lock(&nf_ct_proto_sysctl_mutex);
  154. if (l3proto->ctl_table_header != NULL)
  155. nf_ct_unregister_sysctl(&l3proto->ctl_table_header,
  156. l3proto->ctl_table, NULL);
  157. mutex_unlock(&nf_ct_proto_sysctl_mutex);
  158. #endif
  159. }
  160. int nf_conntrack_l3proto_register(struct nf_conntrack_l3proto *proto)
  161. {
  162. int ret = 0;
  163. if (proto->l3proto >= AF_MAX) {
  164. ret = -EBUSY;
  165. goto out;
  166. }
  167. write_lock_bh(&nf_conntrack_lock);
  168. if (nf_ct_l3protos[proto->l3proto] != &nf_conntrack_l3proto_generic) {
  169. ret = -EBUSY;
  170. goto out_unlock;
  171. }
  172. rcu_assign_pointer(nf_ct_l3protos[proto->l3proto], proto);
  173. write_unlock_bh(&nf_conntrack_lock);
  174. ret = nf_ct_l3proto_register_sysctl(proto);
  175. if (ret < 0)
  176. nf_conntrack_l3proto_unregister(proto);
  177. return ret;
  178. out_unlock:
  179. write_unlock_bh(&nf_conntrack_lock);
  180. out:
  181. return ret;
  182. }
  183. EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_register);
  184. void nf_conntrack_l3proto_unregister(struct nf_conntrack_l3proto *proto)
  185. {
  186. BUG_ON(proto->l3proto >= AF_MAX);
  187. write_lock_bh(&nf_conntrack_lock);
  188. BUG_ON(nf_ct_l3protos[proto->l3proto] != proto);
  189. rcu_assign_pointer(nf_ct_l3protos[proto->l3proto],
  190. &nf_conntrack_l3proto_generic);
  191. write_unlock_bh(&nf_conntrack_lock);
  192. synchronize_rcu();
  193. nf_ct_l3proto_unregister_sysctl(proto);
  194. /* Remove all contrack entries for this protocol */
  195. nf_ct_iterate_cleanup(kill_l3proto, proto);
  196. }
  197. EXPORT_SYMBOL_GPL(nf_conntrack_l3proto_unregister);
  198. static int nf_ct_l4proto_register_sysctl(struct nf_conntrack_l4proto *l4proto)
  199. {
  200. int err = 0;
  201. #ifdef CONFIG_SYSCTL
  202. mutex_lock(&nf_ct_proto_sysctl_mutex);
  203. if (l4proto->ctl_table != NULL) {
  204. err = nf_ct_register_sysctl(l4proto->ctl_table_header,
  205. nf_net_netfilter_sysctl_path,
  206. l4proto->ctl_table,
  207. l4proto->ctl_table_users);
  208. if (err < 0)
  209. goto out;
  210. }
  211. #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
  212. if (l4proto->ctl_compat_table != NULL) {
  213. err = nf_ct_register_sysctl(&l4proto->ctl_compat_table_header,
  214. nf_net_ipv4_netfilter_sysctl_path,
  215. l4proto->ctl_compat_table, NULL);
  216. if (err == 0)
  217. goto out;
  218. nf_ct_unregister_sysctl(l4proto->ctl_table_header,
  219. l4proto->ctl_table,
  220. l4proto->ctl_table_users);
  221. }
  222. #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
  223. out:
  224. mutex_unlock(&nf_ct_proto_sysctl_mutex);
  225. #endif /* CONFIG_SYSCTL */
  226. return err;
  227. }
  228. static void nf_ct_l4proto_unregister_sysctl(struct nf_conntrack_l4proto *l4proto)
  229. {
  230. #ifdef CONFIG_SYSCTL
  231. mutex_lock(&nf_ct_proto_sysctl_mutex);
  232. if (l4proto->ctl_table_header != NULL &&
  233. *l4proto->ctl_table_header != NULL)
  234. nf_ct_unregister_sysctl(l4proto->ctl_table_header,
  235. l4proto->ctl_table,
  236. l4proto->ctl_table_users);
  237. #ifdef CONFIG_NF_CONNTRACK_PROC_COMPAT
  238. if (l4proto->ctl_compat_table_header != NULL)
  239. nf_ct_unregister_sysctl(&l4proto->ctl_compat_table_header,
  240. l4proto->ctl_compat_table, NULL);
  241. #endif /* CONFIG_NF_CONNTRACK_PROC_COMPAT */
  242. mutex_unlock(&nf_ct_proto_sysctl_mutex);
  243. #endif /* CONFIG_SYSCTL */
  244. }
  245. /* FIXME: Allow NULL functions and sub in pointers to generic for
  246. them. --RR */
  247. int nf_conntrack_l4proto_register(struct nf_conntrack_l4proto *l4proto)
  248. {
  249. int ret = 0;
  250. if (l4proto->l3proto >= PF_MAX) {
  251. ret = -EBUSY;
  252. goto out;
  253. }
  254. if (l4proto == &nf_conntrack_l4proto_generic)
  255. return nf_ct_l4proto_register_sysctl(l4proto);
  256. retry:
  257. write_lock_bh(&nf_conntrack_lock);
  258. if (nf_ct_protos[l4proto->l3proto]) {
  259. if (nf_ct_protos[l4proto->l3proto][l4proto->l4proto]
  260. != &nf_conntrack_l4proto_generic) {
  261. ret = -EBUSY;
  262. goto out_unlock;
  263. }
  264. } else {
  265. /* l3proto may be loaded latter. */
  266. struct nf_conntrack_l4proto **proto_array;
  267. int i;
  268. write_unlock_bh(&nf_conntrack_lock);
  269. proto_array = (struct nf_conntrack_l4proto **)
  270. kmalloc(MAX_NF_CT_PROTO *
  271. sizeof(struct nf_conntrack_l4proto *),
  272. GFP_KERNEL);
  273. if (proto_array == NULL) {
  274. ret = -ENOMEM;
  275. goto out;
  276. }
  277. for (i = 0; i < MAX_NF_CT_PROTO; i++)
  278. proto_array[i] = &nf_conntrack_l4proto_generic;
  279. write_lock_bh(&nf_conntrack_lock);
  280. if (nf_ct_protos[l4proto->l3proto]) {
  281. /* bad timing, but no problem */
  282. write_unlock_bh(&nf_conntrack_lock);
  283. kfree(proto_array);
  284. } else {
  285. nf_ct_protos[l4proto->l3proto] = proto_array;
  286. write_unlock_bh(&nf_conntrack_lock);
  287. }
  288. /*
  289. * Just once because array is never freed until unloading
  290. * nf_conntrack.ko
  291. */
  292. goto retry;
  293. }
  294. rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto], l4proto);
  295. write_unlock_bh(&nf_conntrack_lock);
  296. ret = nf_ct_l4proto_register_sysctl(l4proto);
  297. if (ret < 0)
  298. nf_conntrack_l4proto_unregister(l4proto);
  299. return ret;
  300. out_unlock:
  301. write_unlock_bh(&nf_conntrack_lock);
  302. out:
  303. return ret;
  304. }
  305. EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_register);
  306. void nf_conntrack_l4proto_unregister(struct nf_conntrack_l4proto *l4proto)
  307. {
  308. BUG_ON(l4proto->l3proto >= PF_MAX);
  309. if (l4proto == &nf_conntrack_l4proto_generic) {
  310. nf_ct_l4proto_unregister_sysctl(l4proto);
  311. return;
  312. }
  313. write_lock_bh(&nf_conntrack_lock);
  314. BUG_ON(nf_ct_protos[l4proto->l3proto][l4proto->l4proto] != l4proto);
  315. rcu_assign_pointer(nf_ct_protos[l4proto->l3proto][l4proto->l4proto],
  316. &nf_conntrack_l4proto_generic);
  317. write_unlock_bh(&nf_conntrack_lock);
  318. synchronize_rcu();
  319. nf_ct_l4proto_unregister_sysctl(l4proto);
  320. /* Remove all contrack entries for this protocol */
  321. nf_ct_iterate_cleanup(kill_l4proto, l4proto);
  322. }
  323. EXPORT_SYMBOL_GPL(nf_conntrack_l4proto_unregister);