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 13 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 14 15 #include <linux/module.h> 16 #include <linux/errno.h> 17 #include <linux/types.h> 18 #include <linux/socket.h> 19 #include <linux/in.h> 20 #include <linux/kernel.h> 21 #include <linux/jiffies.h> 22 #include <linux/timer.h> 23 #include <linux/string.h> 24 #include <linux/sockios.h> 25 #include <linux/net.h> 26 #include <linux/inet.h> 27 #include <linux/if_arp.h> 28 #include <linux/skbuff.h> 29 #include <linux/slab.h> 30 #include <net/sock.h> 31 #include <linux/uaccess.h> 32 #include <linux/fcntl.h> 33 #include <linux/mm.h> 34 #include <linux/interrupt.h> 35 #include <linux/stat.h> 36 #include <linux/init.h> 37 #include <net/lapb.h> 38 39 static LIST_HEAD(lapb_list); 40 static DEFINE_RWLOCK(lapb_list_lock); 41 42 /* 43 * Free an allocated lapb control block. 44 */ 45 static void lapb_free_cb(struct lapb_cb *lapb) 46 { 47 kfree(lapb); 48 } 49 50 static __inline__ void lapb_hold(struct lapb_cb *lapb) 51 { 52 refcount_inc(&lapb->refcnt); 53 } 54 55 static __inline__ void lapb_put(struct lapb_cb *lapb) 56 { 57 if (refcount_dec_and_test(&lapb->refcnt)) 58 lapb_free_cb(lapb); 59 } 60 61 /* 62 * Socket removal during an interrupt is now safe. 63 */ 64 static void __lapb_remove_cb(struct lapb_cb *lapb) 65 { 66 if (lapb->node.next) { 67 list_del(&lapb->node); 68 lapb_put(lapb); 69 } 70 } 71 72 /* 73 * Add a socket to the bound sockets list. 74 */ 75 static void __lapb_insert_cb(struct lapb_cb *lapb) 76 { 77 list_add(&lapb->node, &lapb_list); 78 lapb_hold(lapb); 79 } 80 81 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev) 82 { 83 struct list_head *entry; 84 struct lapb_cb *lapb, *use = NULL; 85 86 list_for_each(entry, &lapb_list) { 87 lapb = list_entry(entry, struct lapb_cb, node); 88 if (lapb->dev == dev) { 89 use = lapb; 90 break; 91 } 92 } 93 94 if (use) 95 lapb_hold(use); 96 97 return use; 98 } 99 100 static struct lapb_cb *lapb_devtostruct(struct net_device *dev) 101 { 102 struct lapb_cb *rc; 103 104 read_lock_bh(&lapb_list_lock); 105 rc = __lapb_devtostruct(dev); 106 read_unlock_bh(&lapb_list_lock); 107 108 return rc; 109 } 110 /* 111 * Create an empty LAPB control block. 112 */ 113 static struct lapb_cb *lapb_create_cb(void) 114 { 115 struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC); 116 117 if (!lapb) 118 goto out; 119 120 skb_queue_head_init(&lapb->write_queue); 121 skb_queue_head_init(&lapb->ack_queue); 122 123 timer_setup(&lapb->t1timer, NULL, 0); 124 timer_setup(&lapb->t2timer, NULL, 0); 125 126 lapb->t1 = LAPB_DEFAULT_T1; 127 lapb->t2 = LAPB_DEFAULT_T2; 128 lapb->n2 = LAPB_DEFAULT_N2; 129 lapb->mode = LAPB_DEFAULT_MODE; 130 lapb->window = LAPB_DEFAULT_WINDOW; 131 lapb->state = LAPB_STATE_0; 132 refcount_set(&lapb->refcnt, 1); 133 out: 134 return lapb; 135 } 136 137 int lapb_register(struct net_device *dev, 138 const struct lapb_register_struct *callbacks) 139 { 140 struct lapb_cb *lapb; 141 int rc = LAPB_BADTOKEN; 142 143 write_lock_bh(&lapb_list_lock); 144 145 lapb = __lapb_devtostruct(dev); 146 if (lapb) { 147 lapb_put(lapb); 148 goto out; 149 } 150 151 lapb = lapb_create_cb(); 152 rc = LAPB_NOMEM; 153 if (!lapb) 154 goto out; 155 156 lapb->dev = dev; 157 lapb->callbacks = callbacks; 158 159 __lapb_insert_cb(lapb); 160 161 lapb_start_t1timer(lapb); 162 163 rc = LAPB_OK; 164 out: 165 write_unlock_bh(&lapb_list_lock); 166 return rc; 167 } 168 EXPORT_SYMBOL(lapb_register); 169 170 int lapb_unregister(struct net_device *dev) 171 { 172 struct lapb_cb *lapb; 173 int rc = LAPB_BADTOKEN; 174 175 write_lock_bh(&lapb_list_lock); 176 lapb = __lapb_devtostruct(dev); 177 if (!lapb) 178 goto out; 179 lapb_put(lapb); 180 181 lapb_stop_t1timer(lapb); 182 lapb_stop_t2timer(lapb); 183 184 lapb_clear_queues(lapb); 185 186 __lapb_remove_cb(lapb); 187 188 lapb_put(lapb); 189 rc = LAPB_OK; 190 out: 191 write_unlock_bh(&lapb_list_lock); 192 return rc; 193 } 194 EXPORT_SYMBOL(lapb_unregister); 195 196 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms) 197 { 198 int rc = LAPB_BADTOKEN; 199 struct lapb_cb *lapb = lapb_devtostruct(dev); 200 201 if (!lapb) 202 goto out; 203 204 parms->t1 = lapb->t1 / HZ; 205 parms->t2 = lapb->t2 / HZ; 206 parms->n2 = lapb->n2; 207 parms->n2count = lapb->n2count; 208 parms->state = lapb->state; 209 parms->window = lapb->window; 210 parms->mode = lapb->mode; 211 212 if (!timer_pending(&lapb->t1timer)) 213 parms->t1timer = 0; 214 else 215 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ; 216 217 if (!timer_pending(&lapb->t2timer)) 218 parms->t2timer = 0; 219 else 220 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ; 221 222 lapb_put(lapb); 223 rc = LAPB_OK; 224 out: 225 return rc; 226 } 227 EXPORT_SYMBOL(lapb_getparms); 228 229 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms) 230 { 231 int rc = LAPB_BADTOKEN; 232 struct lapb_cb *lapb = lapb_devtostruct(dev); 233 234 if (!lapb) 235 goto out; 236 237 rc = LAPB_INVALUE; 238 if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1) 239 goto out_put; 240 241 if (lapb->state == LAPB_STATE_0) { 242 if (parms->mode & LAPB_EXTENDED) { 243 if (parms->window < 1 || parms->window > 127) 244 goto out_put; 245 } else { 246 if (parms->window < 1 || parms->window > 7) 247 goto out_put; 248 } 249 lapb->mode = parms->mode; 250 lapb->window = parms->window; 251 } 252 253 lapb->t1 = parms->t1 * HZ; 254 lapb->t2 = parms->t2 * HZ; 255 lapb->n2 = parms->n2; 256 257 rc = LAPB_OK; 258 out_put: 259 lapb_put(lapb); 260 out: 261 return rc; 262 } 263 EXPORT_SYMBOL(lapb_setparms); 264 265 int lapb_connect_request(struct net_device *dev) 266 { 267 struct lapb_cb *lapb = lapb_devtostruct(dev); 268 int rc = LAPB_BADTOKEN; 269 270 if (!lapb) 271 goto out; 272 273 rc = LAPB_OK; 274 if (lapb->state == LAPB_STATE_1) 275 goto out_put; 276 277 rc = LAPB_CONNECTED; 278 if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4) 279 goto out_put; 280 281 lapb_establish_data_link(lapb); 282 283 lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev); 284 lapb->state = LAPB_STATE_1; 285 286 rc = LAPB_OK; 287 out_put: 288 lapb_put(lapb); 289 out: 290 return rc; 291 } 292 EXPORT_SYMBOL(lapb_connect_request); 293 294 int lapb_disconnect_request(struct net_device *dev) 295 { 296 struct lapb_cb *lapb = lapb_devtostruct(dev); 297 int rc = LAPB_BADTOKEN; 298 299 if (!lapb) 300 goto out; 301 302 switch (lapb->state) { 303 case LAPB_STATE_0: 304 rc = LAPB_NOTCONNECTED; 305 goto out_put; 306 307 case LAPB_STATE_1: 308 lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev); 309 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); 310 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 311 lapb->state = LAPB_STATE_0; 312 lapb_start_t1timer(lapb); 313 rc = LAPB_NOTCONNECTED; 314 goto out_put; 315 316 case LAPB_STATE_2: 317 rc = LAPB_OK; 318 goto out_put; 319 } 320 321 lapb_clear_queues(lapb); 322 lapb->n2count = 0; 323 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 324 lapb_start_t1timer(lapb); 325 lapb_stop_t2timer(lapb); 326 lapb->state = LAPB_STATE_2; 327 328 lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev); 329 lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev); 330 331 rc = LAPB_OK; 332 out_put: 333 lapb_put(lapb); 334 out: 335 return rc; 336 } 337 EXPORT_SYMBOL(lapb_disconnect_request); 338 339 int lapb_data_request(struct net_device *dev, struct sk_buff *skb) 340 { 341 struct lapb_cb *lapb = lapb_devtostruct(dev); 342 int rc = LAPB_BADTOKEN; 343 344 if (!lapb) 345 goto out; 346 347 rc = LAPB_NOTCONNECTED; 348 if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4) 349 goto out_put; 350 351 skb_queue_tail(&lapb->write_queue, skb); 352 lapb_kick(lapb); 353 rc = LAPB_OK; 354 out_put: 355 lapb_put(lapb); 356 out: 357 return rc; 358 } 359 EXPORT_SYMBOL(lapb_data_request); 360 361 int lapb_data_received(struct net_device *dev, struct sk_buff *skb) 362 { 363 struct lapb_cb *lapb = lapb_devtostruct(dev); 364 int rc = LAPB_BADTOKEN; 365 366 if (lapb) { 367 lapb_data_input(lapb, skb); 368 lapb_put(lapb); 369 rc = LAPB_OK; 370 } 371 372 return rc; 373 } 374 EXPORT_SYMBOL(lapb_data_received); 375 376 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason) 377 { 378 if (lapb->callbacks->connect_confirmation) 379 lapb->callbacks->connect_confirmation(lapb->dev, reason); 380 } 381 382 void lapb_connect_indication(struct lapb_cb *lapb, int reason) 383 { 384 if (lapb->callbacks->connect_indication) 385 lapb->callbacks->connect_indication(lapb->dev, reason); 386 } 387 388 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason) 389 { 390 if (lapb->callbacks->disconnect_confirmation) 391 lapb->callbacks->disconnect_confirmation(lapb->dev, reason); 392 } 393 394 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason) 395 { 396 if (lapb->callbacks->disconnect_indication) 397 lapb->callbacks->disconnect_indication(lapb->dev, reason); 398 } 399 400 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb) 401 { 402 if (lapb->callbacks->data_indication) 403 return lapb->callbacks->data_indication(lapb->dev, skb); 404 405 kfree_skb(skb); 406 return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */ 407 } 408 409 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb) 410 { 411 int used = 0; 412 413 if (lapb->callbacks->data_transmit) { 414 lapb->callbacks->data_transmit(lapb->dev, skb); 415 used = 1; 416 } 417 418 return used; 419 } 420 421 /* Handle device status changes. */ 422 static int lapb_device_event(struct notifier_block *this, unsigned long event, 423 void *ptr) 424 { 425 struct net_device *dev = netdev_notifier_info_to_dev(ptr); 426 struct lapb_cb *lapb; 427 428 if (!net_eq(dev_net(dev), &init_net)) 429 return NOTIFY_DONE; 430 431 if (dev->type != ARPHRD_X25) 432 return NOTIFY_DONE; 433 434 lapb = lapb_devtostruct(dev); 435 if (!lapb) 436 return NOTIFY_DONE; 437 438 switch (event) { 439 case NETDEV_UP: 440 lapb_dbg(0, "(%p) Interface up: %s\n", dev, dev->name); 441 442 if (netif_carrier_ok(dev)) { 443 lapb_dbg(0, "(%p): Carrier is already up: %s\n", dev, 444 dev->name); 445 if (lapb->mode & LAPB_DCE) { 446 lapb_start_t1timer(lapb); 447 } else { 448 if (lapb->state == LAPB_STATE_0) { 449 lapb->state = LAPB_STATE_1; 450 lapb_establish_data_link(lapb); 451 } 452 } 453 } 454 break; 455 case NETDEV_GOING_DOWN: 456 if (netif_carrier_ok(dev)) 457 lapb_disconnect_request(dev); 458 break; 459 case NETDEV_DOWN: 460 lapb_dbg(0, "(%p) Interface down: %s\n", dev, dev->name); 461 lapb_dbg(0, "(%p) S%d -> S0\n", dev, lapb->state); 462 lapb_clear_queues(lapb); 463 lapb->state = LAPB_STATE_0; 464 lapb->n2count = 0; 465 lapb_stop_t1timer(lapb); 466 lapb_stop_t2timer(lapb); 467 break; 468 case NETDEV_CHANGE: 469 if (netif_carrier_ok(dev)) { 470 lapb_dbg(0, "(%p): Carrier detected: %s\n", dev, 471 dev->name); 472 if (lapb->mode & LAPB_DCE) { 473 lapb_start_t1timer(lapb); 474 } else { 475 if (lapb->state == LAPB_STATE_0) { 476 lapb->state = LAPB_STATE_1; 477 lapb_establish_data_link(lapb); 478 } 479 } 480 } else { 481 lapb_dbg(0, "(%p) Carrier lost: %s\n", dev, dev->name); 482 lapb_dbg(0, "(%p) S%d -> S0\n", dev, lapb->state); 483 lapb_clear_queues(lapb); 484 lapb->state = LAPB_STATE_0; 485 lapb->n2count = 0; 486 lapb_stop_t1timer(lapb); 487 lapb_stop_t2timer(lapb); 488 } 489 break; 490 } 491 492 return NOTIFY_DONE; 493 } 494 495 static struct notifier_block lapb_dev_notifier = { 496 .notifier_call = lapb_device_event, 497 }; 498 499 static int __init lapb_init(void) 500 { 501 return register_netdevice_notifier(&lapb_dev_notifier); 502 } 503 504 static void __exit lapb_exit(void) 505 { 506 WARN_ON(!list_empty(&lapb_list)); 507 508 unregister_netdevice_notifier(&lapb_dev_notifier); 509 } 510 511 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 512 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol"); 513 MODULE_LICENSE("GPL"); 514 515 module_init(lapb_init); 516 module_exit(lapb_exit); 517