lapb_iface.c 8.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * LAPB release 002
  4. *
  5. * This code REQUIRES 2.1.15 or higher/ NET3.038
  6. *
  7. * History
  8. * LAPB 001 Jonathan Naylor Started Coding
  9. * LAPB 002 Jonathan Naylor New timer architecture.
  10. * 2000-10-29 Henner Eisen lapb_data_indication() return status.
  11. */
  12. #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  13. #include <linux/module.h>
  14. #include <linux/errno.h>
  15. #include <linux/types.h>
  16. #include <linux/socket.h>
  17. #include <linux/in.h>
  18. #include <linux/kernel.h>
  19. #include <linux/jiffies.h>
  20. #include <linux/timer.h>
  21. #include <linux/string.h>
  22. #include <linux/sockios.h>
  23. #include <linux/net.h>
  24. #include <linux/inet.h>
  25. #include <linux/if_arp.h>
  26. #include <linux/skbuff.h>
  27. #include <linux/slab.h>
  28. #include <net/sock.h>
  29. #include <linux/uaccess.h>
  30. #include <linux/fcntl.h>
  31. #include <linux/mm.h>
  32. #include <linux/interrupt.h>
  33. #include <linux/stat.h>
  34. #include <linux/init.h>
  35. #include <net/lapb.h>
  36. static LIST_HEAD(lapb_list);
  37. static DEFINE_RWLOCK(lapb_list_lock);
  38. /*
  39. * Free an allocated lapb control block.
  40. */
  41. static void lapb_free_cb(struct lapb_cb *lapb)
  42. {
  43. kfree(lapb);
  44. }
  45. static __inline__ void lapb_hold(struct lapb_cb *lapb)
  46. {
  47. refcount_inc(&lapb->refcnt);
  48. }
  49. static __inline__ void lapb_put(struct lapb_cb *lapb)
  50. {
  51. if (refcount_dec_and_test(&lapb->refcnt))
  52. lapb_free_cb(lapb);
  53. }
  54. /*
  55. * Socket removal during an interrupt is now safe.
  56. */
  57. static void __lapb_remove_cb(struct lapb_cb *lapb)
  58. {
  59. if (lapb->node.next) {
  60. list_del(&lapb->node);
  61. lapb_put(lapb);
  62. }
  63. }
  64. /*
  65. * Add a socket to the bound sockets list.
  66. */
  67. static void __lapb_insert_cb(struct lapb_cb *lapb)
  68. {
  69. list_add(&lapb->node, &lapb_list);
  70. lapb_hold(lapb);
  71. }
  72. static struct lapb_cb *__lapb_devtostruct(struct net_device *dev)
  73. {
  74. struct list_head *entry;
  75. struct lapb_cb *lapb, *use = NULL;
  76. list_for_each(entry, &lapb_list) {
  77. lapb = list_entry(entry, struct lapb_cb, node);
  78. if (lapb->dev == dev) {
  79. use = lapb;
  80. break;
  81. }
  82. }
  83. if (use)
  84. lapb_hold(use);
  85. return use;
  86. }
  87. static struct lapb_cb *lapb_devtostruct(struct net_device *dev)
  88. {
  89. struct lapb_cb *rc;
  90. read_lock_bh(&lapb_list_lock);
  91. rc = __lapb_devtostruct(dev);
  92. read_unlock_bh(&lapb_list_lock);
  93. return rc;
  94. }
  95. /*
  96. * Create an empty LAPB control block.
  97. */
  98. static struct lapb_cb *lapb_create_cb(void)
  99. {
  100. struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC);
  101. if (!lapb)
  102. goto out;
  103. skb_queue_head_init(&lapb->write_queue);
  104. skb_queue_head_init(&lapb->ack_queue);
  105. timer_setup(&lapb->t1timer, NULL, 0);
  106. timer_setup(&lapb->t2timer, NULL, 0);
  107. lapb->t1 = LAPB_DEFAULT_T1;
  108. lapb->t2 = LAPB_DEFAULT_T2;
  109. lapb->n2 = LAPB_DEFAULT_N2;
  110. lapb->mode = LAPB_DEFAULT_MODE;
  111. lapb->window = LAPB_DEFAULT_WINDOW;
  112. lapb->state = LAPB_STATE_0;
  113. refcount_set(&lapb->refcnt, 1);
  114. out:
  115. return lapb;
  116. }
  117. int lapb_register(struct net_device *dev,
  118. const struct lapb_register_struct *callbacks)
  119. {
  120. struct lapb_cb *lapb;
  121. int rc = LAPB_BADTOKEN;
  122. write_lock_bh(&lapb_list_lock);
  123. lapb = __lapb_devtostruct(dev);
  124. if (lapb) {
  125. lapb_put(lapb);
  126. goto out;
  127. }
  128. lapb = lapb_create_cb();
  129. rc = LAPB_NOMEM;
  130. if (!lapb)
  131. goto out;
  132. lapb->dev = dev;
  133. lapb->callbacks = callbacks;
  134. __lapb_insert_cb(lapb);
  135. lapb_start_t1timer(lapb);
  136. rc = LAPB_OK;
  137. out:
  138. write_unlock_bh(&lapb_list_lock);
  139. return rc;
  140. }
  141. EXPORT_SYMBOL(lapb_register);
  142. int lapb_unregister(struct net_device *dev)
  143. {
  144. struct lapb_cb *lapb;
  145. int rc = LAPB_BADTOKEN;
  146. write_lock_bh(&lapb_list_lock);
  147. lapb = __lapb_devtostruct(dev);
  148. if (!lapb)
  149. goto out;
  150. lapb_put(lapb);
  151. lapb_stop_t1timer(lapb);
  152. lapb_stop_t2timer(lapb);
  153. lapb_clear_queues(lapb);
  154. __lapb_remove_cb(lapb);
  155. lapb_put(lapb);
  156. rc = LAPB_OK;
  157. out:
  158. write_unlock_bh(&lapb_list_lock);
  159. return rc;
  160. }
  161. EXPORT_SYMBOL(lapb_unregister);
  162. int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms)
  163. {
  164. int rc = LAPB_BADTOKEN;
  165. struct lapb_cb *lapb = lapb_devtostruct(dev);
  166. if (!lapb)
  167. goto out;
  168. parms->t1 = lapb->t1 / HZ;
  169. parms->t2 = lapb->t2 / HZ;
  170. parms->n2 = lapb->n2;
  171. parms->n2count = lapb->n2count;
  172. parms->state = lapb->state;
  173. parms->window = lapb->window;
  174. parms->mode = lapb->mode;
  175. if (!timer_pending(&lapb->t1timer))
  176. parms->t1timer = 0;
  177. else
  178. parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ;
  179. if (!timer_pending(&lapb->t2timer))
  180. parms->t2timer = 0;
  181. else
  182. parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ;
  183. lapb_put(lapb);
  184. rc = LAPB_OK;
  185. out:
  186. return rc;
  187. }
  188. EXPORT_SYMBOL(lapb_getparms);
  189. int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms)
  190. {
  191. int rc = LAPB_BADTOKEN;
  192. struct lapb_cb *lapb = lapb_devtostruct(dev);
  193. if (!lapb)
  194. goto out;
  195. rc = LAPB_INVALUE;
  196. if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1)
  197. goto out_put;
  198. if (lapb->state == LAPB_STATE_0) {
  199. if (parms->mode & LAPB_EXTENDED) {
  200. if (parms->window < 1 || parms->window > 127)
  201. goto out_put;
  202. } else {
  203. if (parms->window < 1 || parms->window > 7)
  204. goto out_put;
  205. }
  206. lapb->mode = parms->mode;
  207. lapb->window = parms->window;
  208. }
  209. lapb->t1 = parms->t1 * HZ;
  210. lapb->t2 = parms->t2 * HZ;
  211. lapb->n2 = parms->n2;
  212. rc = LAPB_OK;
  213. out_put:
  214. lapb_put(lapb);
  215. out:
  216. return rc;
  217. }
  218. EXPORT_SYMBOL(lapb_setparms);
  219. int lapb_connect_request(struct net_device *dev)
  220. {
  221. struct lapb_cb *lapb = lapb_devtostruct(dev);
  222. int rc = LAPB_BADTOKEN;
  223. if (!lapb)
  224. goto out;
  225. rc = LAPB_OK;
  226. if (lapb->state == LAPB_STATE_1)
  227. goto out_put;
  228. rc = LAPB_CONNECTED;
  229. if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4)
  230. goto out_put;
  231. lapb_establish_data_link(lapb);
  232. lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev);
  233. lapb->state = LAPB_STATE_1;
  234. rc = LAPB_OK;
  235. out_put:
  236. lapb_put(lapb);
  237. out:
  238. return rc;
  239. }
  240. EXPORT_SYMBOL(lapb_connect_request);
  241. int lapb_disconnect_request(struct net_device *dev)
  242. {
  243. struct lapb_cb *lapb = lapb_devtostruct(dev);
  244. int rc = LAPB_BADTOKEN;
  245. if (!lapb)
  246. goto out;
  247. switch (lapb->state) {
  248. case LAPB_STATE_0:
  249. rc = LAPB_NOTCONNECTED;
  250. goto out_put;
  251. case LAPB_STATE_1:
  252. lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev);
  253. lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev);
  254. lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
  255. lapb->state = LAPB_STATE_0;
  256. lapb_start_t1timer(lapb);
  257. rc = LAPB_NOTCONNECTED;
  258. goto out_put;
  259. case LAPB_STATE_2:
  260. rc = LAPB_OK;
  261. goto out_put;
  262. }
  263. lapb_clear_queues(lapb);
  264. lapb->n2count = 0;
  265. lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND);
  266. lapb_start_t1timer(lapb);
  267. lapb_stop_t2timer(lapb);
  268. lapb->state = LAPB_STATE_2;
  269. lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev);
  270. lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev);
  271. rc = LAPB_OK;
  272. out_put:
  273. lapb_put(lapb);
  274. out:
  275. return rc;
  276. }
  277. EXPORT_SYMBOL(lapb_disconnect_request);
  278. int lapb_data_request(struct net_device *dev, struct sk_buff *skb)
  279. {
  280. struct lapb_cb *lapb = lapb_devtostruct(dev);
  281. int rc = LAPB_BADTOKEN;
  282. if (!lapb)
  283. goto out;
  284. rc = LAPB_NOTCONNECTED;
  285. if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4)
  286. goto out_put;
  287. skb_queue_tail(&lapb->write_queue, skb);
  288. lapb_kick(lapb);
  289. rc = LAPB_OK;
  290. out_put:
  291. lapb_put(lapb);
  292. out:
  293. return rc;
  294. }
  295. EXPORT_SYMBOL(lapb_data_request);
  296. int lapb_data_received(struct net_device *dev, struct sk_buff *skb)
  297. {
  298. struct lapb_cb *lapb = lapb_devtostruct(dev);
  299. int rc = LAPB_BADTOKEN;
  300. if (lapb) {
  301. lapb_data_input(lapb, skb);
  302. lapb_put(lapb);
  303. rc = LAPB_OK;
  304. }
  305. return rc;
  306. }
  307. EXPORT_SYMBOL(lapb_data_received);
  308. void lapb_connect_confirmation(struct lapb_cb *lapb, int reason)
  309. {
  310. if (lapb->callbacks->connect_confirmation)
  311. lapb->callbacks->connect_confirmation(lapb->dev, reason);
  312. }
  313. void lapb_connect_indication(struct lapb_cb *lapb, int reason)
  314. {
  315. if (lapb->callbacks->connect_indication)
  316. lapb->callbacks->connect_indication(lapb->dev, reason);
  317. }
  318. void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason)
  319. {
  320. if (lapb->callbacks->disconnect_confirmation)
  321. lapb->callbacks->disconnect_confirmation(lapb->dev, reason);
  322. }
  323. void lapb_disconnect_indication(struct lapb_cb *lapb, int reason)
  324. {
  325. if (lapb->callbacks->disconnect_indication)
  326. lapb->callbacks->disconnect_indication(lapb->dev, reason);
  327. }
  328. int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb)
  329. {
  330. if (lapb->callbacks->data_indication)
  331. return lapb->callbacks->data_indication(lapb->dev, skb);
  332. kfree_skb(skb);
  333. return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */
  334. }
  335. int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb)
  336. {
  337. int used = 0;
  338. if (lapb->callbacks->data_transmit) {
  339. lapb->callbacks->data_transmit(lapb->dev, skb);
  340. used = 1;
  341. }
  342. return used;
  343. }
  344. static int __init lapb_init(void)
  345. {
  346. return 0;
  347. }
  348. static void __exit lapb_exit(void)
  349. {
  350. WARN_ON(!list_empty(&lapb_list));
  351. }
  352. MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
  353. MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol");
  354. MODULE_LICENSE("GPL");
  355. module_init(lapb_init);
  356. module_exit(lapb_exit);