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 LIST_HEAD(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 (dev_net(dev) != &init_net) 95 goto drop; 96 97 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 98 return NET_RX_DROP; 99 100 if (!pskb_may_pull(skb, 2)) 101 goto drop; 102 103 rcu_read_lock(); 104 lapbeth = lapbeth_get_x25_dev(dev); 105 if (!lapbeth) 106 goto drop_unlock; 107 if (!netif_running(lapbeth->axdev)) 108 goto drop_unlock; 109 110 lapbeth->stats.rx_packets++; 111 112 len = skb->data[0] + skb->data[1] * 256; 113 lapbeth->stats.rx_bytes += len; 114 115 skb_pull(skb, 2); /* Remove the length bytes */ 116 skb_trim(skb, len); /* Set the length of the data */ 117 118 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 119 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 120 goto drop_unlock; 121 } 122 out: 123 rcu_read_unlock(); 124 return 0; 125 drop_unlock: 126 kfree_skb(skb); 127 goto out; 128 drop: 129 kfree_skb(skb); 130 return 0; 131 } 132 133 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 134 { 135 unsigned char *ptr; 136 137 skb_push(skb, 1); 138 139 if (skb_cow(skb, 1)) 140 return NET_RX_DROP; 141 142 ptr = skb->data; 143 *ptr = 0x00; 144 145 skb->protocol = x25_type_trans(skb, dev); 146 return netif_rx(skb); 147 } 148 149 /* 150 * Send a LAPB frame via an ethernet interface 151 */ 152 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev) 153 { 154 int err = -ENODEV; 155 156 /* 157 * Just to be *really* sure not to send anything if the interface 158 * is down, the ethernet device may have gone. 159 */ 160 if (!netif_running(dev)) { 161 goto drop; 162 } 163 164 switch (skb->data[0]) { 165 case 0x00: 166 err = 0; 167 break; 168 case 0x01: 169 if ((err = lapb_connect_request(dev)) != LAPB_OK) 170 printk(KERN_ERR "lapbeth: lapb_connect_request " 171 "error: %d\n", err); 172 goto drop_ok; 173 case 0x02: 174 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 175 printk(KERN_ERR "lapbeth: lapb_disconnect_request " 176 "err: %d\n", err); 177 /* Fall thru */ 178 default: 179 goto drop_ok; 180 } 181 182 skb_pull(skb, 1); 183 184 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 185 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); 186 err = -ENOMEM; 187 goto drop; 188 } 189 err = 0; 190 out: 191 return err; 192 drop_ok: 193 err = 0; 194 drop: 195 kfree_skb(skb); 196 goto out; 197 } 198 199 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 200 { 201 struct lapbethdev *lapbeth = netdev_priv(ndev); 202 unsigned char *ptr; 203 struct net_device *dev; 204 int size = skb->len; 205 206 skb->protocol = htons(ETH_P_X25); 207 208 ptr = skb_push(skb, 2); 209 210 *ptr++ = size % 256; 211 *ptr++ = size / 256; 212 213 lapbeth->stats.tx_packets++; 214 lapbeth->stats.tx_bytes += size; 215 216 skb->dev = dev = lapbeth->ethdev; 217 218 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 219 220 dev_queue_xmit(skb); 221 } 222 223 static void lapbeth_connected(struct net_device *dev, int reason) 224 { 225 unsigned char *ptr; 226 struct sk_buff *skb = dev_alloc_skb(1); 227 228 if (!skb) { 229 printk(KERN_ERR "lapbeth: out of memory\n"); 230 return; 231 } 232 233 ptr = skb_put(skb, 1); 234 *ptr = 0x01; 235 236 skb->protocol = x25_type_trans(skb, dev); 237 netif_rx(skb); 238 } 239 240 static void lapbeth_disconnected(struct net_device *dev, int reason) 241 { 242 unsigned char *ptr; 243 struct sk_buff *skb = dev_alloc_skb(1); 244 245 if (!skb) { 246 printk(KERN_ERR "lapbeth: out of memory\n"); 247 return; 248 } 249 250 ptr = skb_put(skb, 1); 251 *ptr = 0x02; 252 253 skb->protocol = x25_type_trans(skb, dev); 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 } 330 331 /* 332 * Setup a new device. 333 */ 334 static int lapbeth_new_device(struct net_device *dev) 335 { 336 struct net_device *ndev; 337 struct lapbethdev *lapbeth; 338 int rc = -ENOMEM; 339 340 ASSERT_RTNL(); 341 342 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 343 lapbeth_setup); 344 if (!ndev) 345 goto out; 346 347 lapbeth = netdev_priv(ndev); 348 lapbeth->axdev = ndev; 349 350 dev_hold(dev); 351 lapbeth->ethdev = dev; 352 353 rc = dev_alloc_name(ndev, ndev->name); 354 if (rc < 0) 355 goto fail; 356 357 rc = -EIO; 358 if (register_netdevice(ndev)) 359 goto fail; 360 361 list_add_rcu(&lapbeth->node, &lapbeth_devices); 362 rc = 0; 363 out: 364 return rc; 365 fail: 366 dev_put(dev); 367 free_netdev(ndev); 368 kfree(lapbeth); 369 goto out; 370 } 371 372 /* 373 * Free a lapb network device. 374 */ 375 static void lapbeth_free_device(struct lapbethdev *lapbeth) 376 { 377 dev_put(lapbeth->ethdev); 378 list_del_rcu(&lapbeth->node); 379 unregister_netdevice(lapbeth->axdev); 380 } 381 382 /* 383 * Handle device status changes. 384 * 385 * Called from notifier with RTNL held. 386 */ 387 static int lapbeth_device_event(struct notifier_block *this, 388 unsigned long event, void *ptr) 389 { 390 struct lapbethdev *lapbeth; 391 struct net_device *dev = ptr; 392 393 if (dev_net(dev) != &init_net) 394 return NOTIFY_DONE; 395 396 if (!dev_is_ethdev(dev)) 397 return NOTIFY_DONE; 398 399 switch (event) { 400 case NETDEV_UP: 401 /* New ethernet device -> new LAPB interface */ 402 if (lapbeth_get_x25_dev(dev) == NULL) 403 lapbeth_new_device(dev); 404 break; 405 case NETDEV_DOWN: 406 /* ethernet device closed -> close LAPB interface */ 407 lapbeth = lapbeth_get_x25_dev(dev); 408 if (lapbeth) 409 dev_close(lapbeth->axdev); 410 break; 411 case NETDEV_UNREGISTER: 412 /* ethernet device disappears -> remove LAPB interface */ 413 lapbeth = lapbeth_get_x25_dev(dev); 414 if (lapbeth) 415 lapbeth_free_device(lapbeth); 416 break; 417 } 418 419 return NOTIFY_DONE; 420 } 421 422 /* ------------------------------------------------------------------------ */ 423 424 static struct packet_type lapbeth_packet_type = { 425 .type = __constant_htons(ETH_P_DEC), 426 .func = lapbeth_rcv, 427 }; 428 429 static struct notifier_block lapbeth_dev_notifier = { 430 .notifier_call = lapbeth_device_event, 431 }; 432 433 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n"; 434 435 static int __init lapbeth_init_driver(void) 436 { 437 dev_add_pack(&lapbeth_packet_type); 438 439 register_netdevice_notifier(&lapbeth_dev_notifier); 440 441 printk(banner); 442 443 return 0; 444 } 445 module_init(lapbeth_init_driver); 446 447 static void __exit lapbeth_cleanup_driver(void) 448 { 449 struct lapbethdev *lapbeth; 450 struct list_head *entry, *tmp; 451 452 dev_remove_pack(&lapbeth_packet_type); 453 unregister_netdevice_notifier(&lapbeth_dev_notifier); 454 455 rtnl_lock(); 456 list_for_each_safe(entry, tmp, &lapbeth_devices) { 457 lapbeth = list_entry(entry, struct lapbethdev, node); 458 459 dev_put(lapbeth->ethdev); 460 unregister_netdevice(lapbeth->axdev); 461 } 462 rtnl_unlock(); 463 } 464 module_exit(lapbeth_cleanup_driver); 465 466 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 467 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 468 MODULE_LICENSE("GPL"); 469