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 EXPORT_SYMBOL(lapb_register); 72 73 /* 74 * Add a socket to the bound sockets list. 75 */ 76 static void __lapb_insert_cb(struct lapb_cb *lapb) 77 { 78 list_add(&lapb->node, &lapb_list); 79 lapb_hold(lapb); 80 } 81 82 static struct lapb_cb *__lapb_devtostruct(struct net_device *dev) 83 { 84 struct list_head *entry; 85 struct lapb_cb *lapb, *use = NULL; 86 87 list_for_each(entry, &lapb_list) { 88 lapb = list_entry(entry, struct lapb_cb, node); 89 if (lapb->dev == dev) { 90 use = lapb; 91 break; 92 } 93 } 94 95 if (use) 96 lapb_hold(use); 97 98 return use; 99 } 100 101 static struct lapb_cb *lapb_devtostruct(struct net_device *dev) 102 { 103 struct lapb_cb *rc; 104 105 read_lock_bh(&lapb_list_lock); 106 rc = __lapb_devtostruct(dev); 107 read_unlock_bh(&lapb_list_lock); 108 109 return rc; 110 } 111 /* 112 * Create an empty LAPB control block. 113 */ 114 static struct lapb_cb *lapb_create_cb(void) 115 { 116 struct lapb_cb *lapb = kzalloc(sizeof(*lapb), GFP_ATOMIC); 117 118 119 if (!lapb) 120 goto out; 121 122 skb_queue_head_init(&lapb->write_queue); 123 skb_queue_head_init(&lapb->ack_queue); 124 125 timer_setup(&lapb->t1timer, NULL, 0); 126 timer_setup(&lapb->t2timer, NULL, 0); 127 128 lapb->t1 = LAPB_DEFAULT_T1; 129 lapb->t2 = LAPB_DEFAULT_T2; 130 lapb->n2 = LAPB_DEFAULT_N2; 131 lapb->mode = LAPB_DEFAULT_MODE; 132 lapb->window = LAPB_DEFAULT_WINDOW; 133 lapb->state = LAPB_STATE_0; 134 refcount_set(&lapb->refcnt, 1); 135 out: 136 return lapb; 137 } 138 139 int lapb_register(struct net_device *dev, 140 const struct lapb_register_struct *callbacks) 141 { 142 struct lapb_cb *lapb; 143 int rc = LAPB_BADTOKEN; 144 145 write_lock_bh(&lapb_list_lock); 146 147 lapb = __lapb_devtostruct(dev); 148 if (lapb) { 149 lapb_put(lapb); 150 goto out; 151 } 152 153 lapb = lapb_create_cb(); 154 rc = LAPB_NOMEM; 155 if (!lapb) 156 goto out; 157 158 lapb->dev = dev; 159 lapb->callbacks = callbacks; 160 161 __lapb_insert_cb(lapb); 162 163 lapb_start_t1timer(lapb); 164 165 rc = LAPB_OK; 166 out: 167 write_unlock_bh(&lapb_list_lock); 168 return rc; 169 } 170 171 int lapb_unregister(struct net_device *dev) 172 { 173 struct lapb_cb *lapb; 174 int rc = LAPB_BADTOKEN; 175 176 write_lock_bh(&lapb_list_lock); 177 lapb = __lapb_devtostruct(dev); 178 if (!lapb) 179 goto out; 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 static int __init lapb_init(void) 422 { 423 return 0; 424 } 425 426 static void __exit lapb_exit(void) 427 { 428 WARN_ON(!list_empty(&lapb_list)); 429 } 430 431 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 432 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol"); 433 MODULE_LICENSE("GPL"); 434 435 module_init(lapb_init); 436 module_exit(lapb_exit); 437