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; 179 180 lapb_stop_t1timer(lapb); 181 lapb_stop_t2timer(lapb); 182 183 lapb_clear_queues(lapb); 184 185 __lapb_remove_cb(lapb); 186 187 lapb_put(lapb); 188 rc = LAPB_OK; 189 out: 190 write_unlock_bh(&lapb_list_lock); 191 return rc; 192 } 193 EXPORT_SYMBOL(lapb_unregister); 194 195 int lapb_getparms(struct net_device *dev, struct lapb_parms_struct *parms) 196 { 197 int rc = LAPB_BADTOKEN; 198 struct lapb_cb *lapb = lapb_devtostruct(dev); 199 200 if (!lapb) 201 goto out; 202 203 parms->t1 = lapb->t1 / HZ; 204 parms->t2 = lapb->t2 / HZ; 205 parms->n2 = lapb->n2; 206 parms->n2count = lapb->n2count; 207 parms->state = lapb->state; 208 parms->window = lapb->window; 209 parms->mode = lapb->mode; 210 211 if (!timer_pending(&lapb->t1timer)) 212 parms->t1timer = 0; 213 else 214 parms->t1timer = (lapb->t1timer.expires - jiffies) / HZ; 215 216 if (!timer_pending(&lapb->t2timer)) 217 parms->t2timer = 0; 218 else 219 parms->t2timer = (lapb->t2timer.expires - jiffies) / HZ; 220 221 lapb_put(lapb); 222 rc = LAPB_OK; 223 out: 224 return rc; 225 } 226 EXPORT_SYMBOL(lapb_getparms); 227 228 int lapb_setparms(struct net_device *dev, struct lapb_parms_struct *parms) 229 { 230 int rc = LAPB_BADTOKEN; 231 struct lapb_cb *lapb = lapb_devtostruct(dev); 232 233 if (!lapb) 234 goto out; 235 236 rc = LAPB_INVALUE; 237 if (parms->t1 < 1 || parms->t2 < 1 || parms->n2 < 1) 238 goto out_put; 239 240 if (lapb->state == LAPB_STATE_0) { 241 if (parms->mode & LAPB_EXTENDED) { 242 if (parms->window < 1 || parms->window > 127) 243 goto out_put; 244 } else { 245 if (parms->window < 1 || parms->window > 7) 246 goto out_put; 247 } 248 lapb->mode = parms->mode; 249 lapb->window = parms->window; 250 } 251 252 lapb->t1 = parms->t1 * HZ; 253 lapb->t2 = parms->t2 * HZ; 254 lapb->n2 = parms->n2; 255 256 rc = LAPB_OK; 257 out_put: 258 lapb_put(lapb); 259 out: 260 return rc; 261 } 262 EXPORT_SYMBOL(lapb_setparms); 263 264 int lapb_connect_request(struct net_device *dev) 265 { 266 struct lapb_cb *lapb = lapb_devtostruct(dev); 267 int rc = LAPB_BADTOKEN; 268 269 if (!lapb) 270 goto out; 271 272 rc = LAPB_OK; 273 if (lapb->state == LAPB_STATE_1) 274 goto out_put; 275 276 rc = LAPB_CONNECTED; 277 if (lapb->state == LAPB_STATE_3 || lapb->state == LAPB_STATE_4) 278 goto out_put; 279 280 lapb_establish_data_link(lapb); 281 282 lapb_dbg(0, "(%p) S0 -> S1\n", lapb->dev); 283 lapb->state = LAPB_STATE_1; 284 285 rc = LAPB_OK; 286 out_put: 287 lapb_put(lapb); 288 out: 289 return rc; 290 } 291 EXPORT_SYMBOL(lapb_connect_request); 292 293 int lapb_disconnect_request(struct net_device *dev) 294 { 295 struct lapb_cb *lapb = lapb_devtostruct(dev); 296 int rc = LAPB_BADTOKEN; 297 298 if (!lapb) 299 goto out; 300 301 switch (lapb->state) { 302 case LAPB_STATE_0: 303 rc = LAPB_NOTCONNECTED; 304 goto out_put; 305 306 case LAPB_STATE_1: 307 lapb_dbg(1, "(%p) S1 TX DISC(1)\n", lapb->dev); 308 lapb_dbg(0, "(%p) S1 -> S0\n", lapb->dev); 309 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 310 lapb->state = LAPB_STATE_0; 311 lapb_start_t1timer(lapb); 312 rc = LAPB_NOTCONNECTED; 313 goto out_put; 314 315 case LAPB_STATE_2: 316 rc = LAPB_OK; 317 goto out_put; 318 } 319 320 lapb_clear_queues(lapb); 321 lapb->n2count = 0; 322 lapb_send_control(lapb, LAPB_DISC, LAPB_POLLON, LAPB_COMMAND); 323 lapb_start_t1timer(lapb); 324 lapb_stop_t2timer(lapb); 325 lapb->state = LAPB_STATE_2; 326 327 lapb_dbg(1, "(%p) S3 DISC(1)\n", lapb->dev); 328 lapb_dbg(0, "(%p) S3 -> S2\n", lapb->dev); 329 330 rc = LAPB_OK; 331 out_put: 332 lapb_put(lapb); 333 out: 334 return rc; 335 } 336 EXPORT_SYMBOL(lapb_disconnect_request); 337 338 int lapb_data_request(struct net_device *dev, struct sk_buff *skb) 339 { 340 struct lapb_cb *lapb = lapb_devtostruct(dev); 341 int rc = LAPB_BADTOKEN; 342 343 if (!lapb) 344 goto out; 345 346 rc = LAPB_NOTCONNECTED; 347 if (lapb->state != LAPB_STATE_3 && lapb->state != LAPB_STATE_4) 348 goto out_put; 349 350 skb_queue_tail(&lapb->write_queue, skb); 351 lapb_kick(lapb); 352 rc = LAPB_OK; 353 out_put: 354 lapb_put(lapb); 355 out: 356 return rc; 357 } 358 EXPORT_SYMBOL(lapb_data_request); 359 360 int lapb_data_received(struct net_device *dev, struct sk_buff *skb) 361 { 362 struct lapb_cb *lapb = lapb_devtostruct(dev); 363 int rc = LAPB_BADTOKEN; 364 365 if (lapb) { 366 lapb_data_input(lapb, skb); 367 lapb_put(lapb); 368 rc = LAPB_OK; 369 } 370 371 return rc; 372 } 373 EXPORT_SYMBOL(lapb_data_received); 374 375 void lapb_connect_confirmation(struct lapb_cb *lapb, int reason) 376 { 377 if (lapb->callbacks->connect_confirmation) 378 lapb->callbacks->connect_confirmation(lapb->dev, reason); 379 } 380 381 void lapb_connect_indication(struct lapb_cb *lapb, int reason) 382 { 383 if (lapb->callbacks->connect_indication) 384 lapb->callbacks->connect_indication(lapb->dev, reason); 385 } 386 387 void lapb_disconnect_confirmation(struct lapb_cb *lapb, int reason) 388 { 389 if (lapb->callbacks->disconnect_confirmation) 390 lapb->callbacks->disconnect_confirmation(lapb->dev, reason); 391 } 392 393 void lapb_disconnect_indication(struct lapb_cb *lapb, int reason) 394 { 395 if (lapb->callbacks->disconnect_indication) 396 lapb->callbacks->disconnect_indication(lapb->dev, reason); 397 } 398 399 int lapb_data_indication(struct lapb_cb *lapb, struct sk_buff *skb) 400 { 401 if (lapb->callbacks->data_indication) 402 return lapb->callbacks->data_indication(lapb->dev, skb); 403 404 kfree_skb(skb); 405 return NET_RX_SUCCESS; /* For now; must be != NET_RX_DROP */ 406 } 407 408 int lapb_data_transmit(struct lapb_cb *lapb, struct sk_buff *skb) 409 { 410 int used = 0; 411 412 if (lapb->callbacks->data_transmit) { 413 lapb->callbacks->data_transmit(lapb->dev, skb); 414 used = 1; 415 } 416 417 return used; 418 } 419 420 static int __init lapb_init(void) 421 { 422 return 0; 423 } 424 425 static void __exit lapb_exit(void) 426 { 427 WARN_ON(!list_empty(&lapb_list)); 428 } 429 430 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 431 MODULE_DESCRIPTION("The X.25 Link Access Procedure B link layer protocol"); 432 MODULE_LICENSE("GPL"); 433 434 module_init(lapb_init); 435 module_exit(lapb_exit); 436