1 /* 2 * "LAPB via ethernet" driver release 001 3 * 4 * This code REQUIRES 2.1.15 or higher/ NET3.038 5 * 6 * This module: 7 * This module is free software; you can redistribute it and/or 8 * modify it under the terms of the GNU General Public License 9 * as published by the Free Software Foundation; either version 10 * 2 of the License, or (at your option) any later version. 11 * 12 * This is a "pseudo" network driver to allow LAPB over Ethernet. 13 * 14 * This driver can use any ethernet destination address, and can be 15 * limited to accept frames from one dedicated ethernet card only. 16 * 17 * History 18 * LAPBETH 001 Jonathan Naylor Cloned from bpqether.c 19 * 2000-10-29 Henner Eisen lapb_data_indication() return status. 20 * 2000-11-14 Henner Eisen dev_hold/put, NETDEV_GOING_DOWN support 21 */ 22 23 #include <linux/errno.h> 24 #include <linux/types.h> 25 #include <linux/socket.h> 26 #include <linux/in.h> 27 #include <linux/kernel.h> 28 #include <linux/string.h> 29 #include <linux/net.h> 30 #include <linux/inet.h> 31 #include <linux/netdevice.h> 32 #include <linux/if_arp.h> 33 #include <linux/skbuff.h> 34 #include <net/sock.h> 35 #include <asm/system.h> 36 #include <asm/uaccess.h> 37 #include <linux/mm.h> 38 #include <linux/interrupt.h> 39 #include <linux/notifier.h> 40 #include <linux/stat.h> 41 #include <linux/netfilter.h> 42 #include <linux/module.h> 43 #include <linux/lapb.h> 44 #include <linux/init.h> 45 46 #include <net/x25device.h> 47 48 static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 49 50 /* If this number is made larger, check that the temporary string buffer 51 * in lapbeth_new_device is large enough to store the probe device name.*/ 52 #define MAXLAPBDEV 100 53 54 struct lapbethdev { 55 struct list_head node; 56 struct net_device *ethdev; /* link to ethernet device */ 57 struct net_device *axdev; /* lapbeth device (lapb#) */ 58 struct net_device_stats stats; /* some statistics */ 59 }; 60 61 static struct list_head lapbeth_devices = LIST_HEAD_INIT(lapbeth_devices); 62 63 /* ------------------------------------------------------------------------ */ 64 65 /* 66 * Get the LAPB device for the ethernet device 67 */ 68 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) 69 { 70 struct lapbethdev *lapbeth; 71 72 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) { 73 if (lapbeth->ethdev == dev) 74 return lapbeth; 75 } 76 return NULL; 77 } 78 79 static __inline__ int dev_is_ethdev(struct net_device *dev) 80 { 81 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 82 } 83 84 /* ------------------------------------------------------------------------ */ 85 86 /* 87 * Receive a LAPB frame via an ethernet interface. 88 */ 89 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 90 { 91 int len, err; 92 struct lapbethdev *lapbeth; 93 94 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 95 return NET_RX_DROP; 96 97 if (!pskb_may_pull(skb, 2)) 98 goto drop; 99 100 rcu_read_lock(); 101 lapbeth = lapbeth_get_x25_dev(dev); 102 if (!lapbeth) 103 goto drop_unlock; 104 if (!netif_running(lapbeth->axdev)) 105 goto drop_unlock; 106 107 lapbeth->stats.rx_packets++; 108 109 len = skb->data[0] + skb->data[1] * 256; 110 lapbeth->stats.rx_bytes += len; 111 112 skb_pull(skb, 2); /* Remove the length bytes */ 113 skb_trim(skb, len); /* Set the length of the data */ 114 115 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 116 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 117 goto drop_unlock; 118 } 119 out: 120 rcu_read_unlock(); 121 return 0; 122 drop_unlock: 123 kfree_skb(skb); 124 goto out; 125 drop: 126 kfree_skb(skb); 127 return 0; 128 } 129 130 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 131 { 132 unsigned char *ptr; 133 134 skb_push(skb, 1); 135 136 if (skb_cow(skb, 1)) 137 return NET_RX_DROP; 138 139 ptr = skb->data; 140 *ptr = 0x00; 141 142 skb->protocol = x25_type_trans(skb, dev); 143 skb->dev->last_rx = jiffies; 144 return netif_rx(skb); 145 } 146 147 /* 148 * Send a LAPB frame via an ethernet interface 149 */ 150 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev) 151 { 152 int err = -ENODEV; 153 154 /* 155 * Just to be *really* sure not to send anything if the interface 156 * is down, the ethernet device may have gone. 157 */ 158 if (!netif_running(dev)) { 159 goto drop; 160 } 161 162 switch (skb->data[0]) { 163 case 0x00: 164 err = 0; 165 break; 166 case 0x01: 167 if ((err = lapb_connect_request(dev)) != LAPB_OK) 168 printk(KERN_ERR "lapbeth: lapb_connect_request " 169 "error: %d\n", err); 170 goto drop_ok; 171 case 0x02: 172 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 173 printk(KERN_ERR "lapbeth: lapb_disconnect_request " 174 "err: %d\n", err); 175 /* Fall thru */ 176 default: 177 goto drop_ok; 178 } 179 180 skb_pull(skb, 1); 181 182 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 183 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); 184 err = -ENOMEM; 185 goto drop; 186 } 187 err = 0; 188 out: 189 return err; 190 drop_ok: 191 err = 0; 192 drop: 193 kfree_skb(skb); 194 goto out; 195 } 196 197 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 198 { 199 struct lapbethdev *lapbeth = netdev_priv(ndev); 200 unsigned char *ptr; 201 struct net_device *dev; 202 int size = skb->len; 203 204 skb->protocol = htons(ETH_P_X25); 205 206 ptr = skb_push(skb, 2); 207 208 *ptr++ = size % 256; 209 *ptr++ = size / 256; 210 211 lapbeth->stats.tx_packets++; 212 lapbeth->stats.tx_bytes += size; 213 214 skb->dev = dev = lapbeth->ethdev; 215 216 dev->hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 217 218 dev_queue_xmit(skb); 219 } 220 221 static void lapbeth_connected(struct net_device *dev, int reason) 222 { 223 unsigned char *ptr; 224 struct sk_buff *skb = dev_alloc_skb(1); 225 226 if (!skb) { 227 printk(KERN_ERR "lapbeth: out of memory\n"); 228 return; 229 } 230 231 ptr = skb_put(skb, 1); 232 *ptr = 0x01; 233 234 skb->protocol = x25_type_trans(skb, dev); 235 skb->dev->last_rx = jiffies; 236 netif_rx(skb); 237 } 238 239 static void lapbeth_disconnected(struct net_device *dev, int reason) 240 { 241 unsigned char *ptr; 242 struct sk_buff *skb = dev_alloc_skb(1); 243 244 if (!skb) { 245 printk(KERN_ERR "lapbeth: out of memory\n"); 246 return; 247 } 248 249 ptr = skb_put(skb, 1); 250 *ptr = 0x02; 251 252 skb->protocol = x25_type_trans(skb, dev); 253 skb->dev->last_rx = jiffies; 254 netif_rx(skb); 255 } 256 257 /* 258 * Statistics 259 */ 260 static struct net_device_stats *lapbeth_get_stats(struct net_device *dev) 261 { 262 struct lapbethdev *lapbeth = netdev_priv(dev); 263 return &lapbeth->stats; 264 } 265 266 /* 267 * Set AX.25 callsign 268 */ 269 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 270 { 271 struct sockaddr *sa = addr; 272 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 273 return 0; 274 } 275 276 277 static struct lapb_register_struct lapbeth_callbacks = { 278 .connect_confirmation = lapbeth_connected, 279 .connect_indication = lapbeth_connected, 280 .disconnect_confirmation = lapbeth_disconnected, 281 .disconnect_indication = lapbeth_disconnected, 282 .data_indication = lapbeth_data_indication, 283 .data_transmit = lapbeth_data_transmit, 284 285 }; 286 287 /* 288 * open/close a device 289 */ 290 static int lapbeth_open(struct net_device *dev) 291 { 292 int err; 293 294 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 295 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 296 return -ENODEV; 297 } 298 299 netif_start_queue(dev); 300 return 0; 301 } 302 303 static int lapbeth_close(struct net_device *dev) 304 { 305 int err; 306 307 netif_stop_queue(dev); 308 309 if ((err = lapb_unregister(dev)) != LAPB_OK) 310 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 311 312 return 0; 313 } 314 315 /* ------------------------------------------------------------------------ */ 316 317 static void lapbeth_setup(struct net_device *dev) 318 { 319 dev->hard_start_xmit = lapbeth_xmit; 320 dev->open = lapbeth_open; 321 dev->stop = lapbeth_close; 322 dev->destructor = free_netdev; 323 dev->set_mac_address = lapbeth_set_mac_address; 324 dev->get_stats = lapbeth_get_stats; 325 dev->type = ARPHRD_X25; 326 dev->hard_header_len = 3; 327 dev->mtu = 1000; 328 dev->addr_len = 0; 329 SET_MODULE_OWNER(dev); 330 } 331 332 /* 333 * Setup a new device. 334 */ 335 static int lapbeth_new_device(struct net_device *dev) 336 { 337 struct net_device *ndev; 338 struct lapbethdev *lapbeth; 339 int rc = -ENOMEM; 340 341 ASSERT_RTNL(); 342 343 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 344 lapbeth_setup); 345 if (!ndev) 346 goto out; 347 348 lapbeth = netdev_priv(ndev); 349 lapbeth->axdev = ndev; 350 351 dev_hold(dev); 352 lapbeth->ethdev = dev; 353 354 rc = dev_alloc_name(ndev, ndev->name); 355 if (rc < 0) 356 goto fail; 357 358 rc = -EIO; 359 if (register_netdevice(ndev)) 360 goto fail; 361 362 list_add_rcu(&lapbeth->node, &lapbeth_devices); 363 rc = 0; 364 out: 365 return rc; 366 fail: 367 dev_put(dev); 368 free_netdev(ndev); 369 kfree(lapbeth); 370 goto out; 371 } 372 373 /* 374 * Free a lapb network device. 375 */ 376 static void lapbeth_free_device(struct lapbethdev *lapbeth) 377 { 378 dev_put(lapbeth->ethdev); 379 list_del_rcu(&lapbeth->node); 380 unregister_netdevice(lapbeth->axdev); 381 } 382 383 /* 384 * Handle device status changes. 385 * 386 * Called from notifier with RTNL held. 387 */ 388 static int lapbeth_device_event(struct notifier_block *this, 389 unsigned long event, void *ptr) 390 { 391 struct lapbethdev *lapbeth; 392 struct net_device *dev = ptr; 393 394 if (!dev_is_ethdev(dev)) 395 return NOTIFY_DONE; 396 397 switch (event) { 398 case NETDEV_UP: 399 /* New ethernet device -> new LAPB interface */ 400 if (lapbeth_get_x25_dev(dev) == NULL) 401 lapbeth_new_device(dev); 402 break; 403 case NETDEV_DOWN: 404 /* ethernet device closed -> close LAPB interface */ 405 lapbeth = lapbeth_get_x25_dev(dev); 406 if (lapbeth) 407 dev_close(lapbeth->axdev); 408 break; 409 case NETDEV_UNREGISTER: 410 /* ethernet device disappears -> remove LAPB interface */ 411 lapbeth = lapbeth_get_x25_dev(dev); 412 if (lapbeth) 413 lapbeth_free_device(lapbeth); 414 break; 415 } 416 417 return NOTIFY_DONE; 418 } 419 420 /* ------------------------------------------------------------------------ */ 421 422 static struct packet_type lapbeth_packet_type = { 423 .type = __constant_htons(ETH_P_DEC), 424 .func = lapbeth_rcv, 425 }; 426 427 static struct notifier_block lapbeth_dev_notifier = { 428 .notifier_call = lapbeth_device_event, 429 }; 430 431 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n"; 432 433 static int __init lapbeth_init_driver(void) 434 { 435 dev_add_pack(&lapbeth_packet_type); 436 437 register_netdevice_notifier(&lapbeth_dev_notifier); 438 439 printk(banner); 440 441 return 0; 442 } 443 module_init(lapbeth_init_driver); 444 445 static void __exit lapbeth_cleanup_driver(void) 446 { 447 struct lapbethdev *lapbeth; 448 struct list_head *entry, *tmp; 449 450 dev_remove_pack(&lapbeth_packet_type); 451 unregister_netdevice_notifier(&lapbeth_dev_notifier); 452 453 rtnl_lock(); 454 list_for_each_safe(entry, tmp, &lapbeth_devices) { 455 lapbeth = list_entry(entry, struct lapbethdev, node); 456 457 unregister_netdevice(lapbeth->axdev); 458 } 459 rtnl_unlock(); 460 } 461 module_exit(lapbeth_cleanup_driver); 462 463 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 464 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 465 MODULE_LICENSE("GPL"); 466