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 (dev->nd_net != &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 skb->dev->last_rx = jiffies; 147 return netif_rx(skb); 148 } 149 150 /* 151 * Send a LAPB frame via an ethernet interface 152 */ 153 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev) 154 { 155 int err = -ENODEV; 156 157 /* 158 * Just to be *really* sure not to send anything if the interface 159 * is down, the ethernet device may have gone. 160 */ 161 if (!netif_running(dev)) { 162 goto drop; 163 } 164 165 switch (skb->data[0]) { 166 case 0x00: 167 err = 0; 168 break; 169 case 0x01: 170 if ((err = lapb_connect_request(dev)) != LAPB_OK) 171 printk(KERN_ERR "lapbeth: lapb_connect_request " 172 "error: %d\n", err); 173 goto drop_ok; 174 case 0x02: 175 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 176 printk(KERN_ERR "lapbeth: lapb_disconnect_request " 177 "err: %d\n", err); 178 /* Fall thru */ 179 default: 180 goto drop_ok; 181 } 182 183 skb_pull(skb, 1); 184 185 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 186 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); 187 err = -ENOMEM; 188 goto drop; 189 } 190 err = 0; 191 out: 192 return err; 193 drop_ok: 194 err = 0; 195 drop: 196 kfree_skb(skb); 197 goto out; 198 } 199 200 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 201 { 202 struct lapbethdev *lapbeth = netdev_priv(ndev); 203 unsigned char *ptr; 204 struct net_device *dev; 205 int size = skb->len; 206 207 skb->protocol = htons(ETH_P_X25); 208 209 ptr = skb_push(skb, 2); 210 211 *ptr++ = size % 256; 212 *ptr++ = size / 256; 213 214 lapbeth->stats.tx_packets++; 215 lapbeth->stats.tx_bytes += size; 216 217 skb->dev = dev = lapbeth->ethdev; 218 219 dev->hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 220 221 dev_queue_xmit(skb); 222 } 223 224 static void lapbeth_connected(struct net_device *dev, int reason) 225 { 226 unsigned char *ptr; 227 struct sk_buff *skb = dev_alloc_skb(1); 228 229 if (!skb) { 230 printk(KERN_ERR "lapbeth: out of memory\n"); 231 return; 232 } 233 234 ptr = skb_put(skb, 1); 235 *ptr = 0x01; 236 237 skb->protocol = x25_type_trans(skb, dev); 238 skb->dev->last_rx = jiffies; 239 netif_rx(skb); 240 } 241 242 static void lapbeth_disconnected(struct net_device *dev, int reason) 243 { 244 unsigned char *ptr; 245 struct sk_buff *skb = dev_alloc_skb(1); 246 247 if (!skb) { 248 printk(KERN_ERR "lapbeth: out of memory\n"); 249 return; 250 } 251 252 ptr = skb_put(skb, 1); 253 *ptr = 0x02; 254 255 skb->protocol = x25_type_trans(skb, dev); 256 skb->dev->last_rx = jiffies; 257 netif_rx(skb); 258 } 259 260 /* 261 * Statistics 262 */ 263 static struct net_device_stats *lapbeth_get_stats(struct net_device *dev) 264 { 265 struct lapbethdev *lapbeth = netdev_priv(dev); 266 return &lapbeth->stats; 267 } 268 269 /* 270 * Set AX.25 callsign 271 */ 272 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 273 { 274 struct sockaddr *sa = addr; 275 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 276 return 0; 277 } 278 279 280 static struct lapb_register_struct lapbeth_callbacks = { 281 .connect_confirmation = lapbeth_connected, 282 .connect_indication = lapbeth_connected, 283 .disconnect_confirmation = lapbeth_disconnected, 284 .disconnect_indication = lapbeth_disconnected, 285 .data_indication = lapbeth_data_indication, 286 .data_transmit = lapbeth_data_transmit, 287 288 }; 289 290 /* 291 * open/close a device 292 */ 293 static int lapbeth_open(struct net_device *dev) 294 { 295 int err; 296 297 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 298 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 299 return -ENODEV; 300 } 301 302 netif_start_queue(dev); 303 return 0; 304 } 305 306 static int lapbeth_close(struct net_device *dev) 307 { 308 int err; 309 310 netif_stop_queue(dev); 311 312 if ((err = lapb_unregister(dev)) != LAPB_OK) 313 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 314 315 return 0; 316 } 317 318 /* ------------------------------------------------------------------------ */ 319 320 static void lapbeth_setup(struct net_device *dev) 321 { 322 dev->hard_start_xmit = lapbeth_xmit; 323 dev->open = lapbeth_open; 324 dev->stop = lapbeth_close; 325 dev->destructor = free_netdev; 326 dev->set_mac_address = lapbeth_set_mac_address; 327 dev->get_stats = lapbeth_get_stats; 328 dev->type = ARPHRD_X25; 329 dev->hard_header_len = 3; 330 dev->mtu = 1000; 331 dev->addr_len = 0; 332 SET_MODULE_OWNER(dev); 333 } 334 335 /* 336 * Setup a new device. 337 */ 338 static int lapbeth_new_device(struct net_device *dev) 339 { 340 struct net_device *ndev; 341 struct lapbethdev *lapbeth; 342 int rc = -ENOMEM; 343 344 ASSERT_RTNL(); 345 346 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 347 lapbeth_setup); 348 if (!ndev) 349 goto out; 350 351 lapbeth = netdev_priv(ndev); 352 lapbeth->axdev = ndev; 353 354 dev_hold(dev); 355 lapbeth->ethdev = dev; 356 357 rc = dev_alloc_name(ndev, ndev->name); 358 if (rc < 0) 359 goto fail; 360 361 rc = -EIO; 362 if (register_netdevice(ndev)) 363 goto fail; 364 365 list_add_rcu(&lapbeth->node, &lapbeth_devices); 366 rc = 0; 367 out: 368 return rc; 369 fail: 370 dev_put(dev); 371 free_netdev(ndev); 372 kfree(lapbeth); 373 goto out; 374 } 375 376 /* 377 * Free a lapb network device. 378 */ 379 static void lapbeth_free_device(struct lapbethdev *lapbeth) 380 { 381 dev_put(lapbeth->ethdev); 382 list_del_rcu(&lapbeth->node); 383 unregister_netdevice(lapbeth->axdev); 384 } 385 386 /* 387 * Handle device status changes. 388 * 389 * Called from notifier with RTNL held. 390 */ 391 static int lapbeth_device_event(struct notifier_block *this, 392 unsigned long event, void *ptr) 393 { 394 struct lapbethdev *lapbeth; 395 struct net_device *dev = ptr; 396 397 if (!dev_is_ethdev(dev)) 398 return NOTIFY_DONE; 399 400 switch (event) { 401 case NETDEV_UP: 402 /* New ethernet device -> new LAPB interface */ 403 if (lapbeth_get_x25_dev(dev) == NULL) 404 lapbeth_new_device(dev); 405 break; 406 case NETDEV_DOWN: 407 /* ethernet device closed -> close LAPB interface */ 408 lapbeth = lapbeth_get_x25_dev(dev); 409 if (lapbeth) 410 dev_close(lapbeth->axdev); 411 break; 412 case NETDEV_UNREGISTER: 413 /* ethernet device disappears -> remove LAPB interface */ 414 lapbeth = lapbeth_get_x25_dev(dev); 415 if (lapbeth) 416 lapbeth_free_device(lapbeth); 417 break; 418 } 419 420 return NOTIFY_DONE; 421 } 422 423 /* ------------------------------------------------------------------------ */ 424 425 static struct packet_type lapbeth_packet_type = { 426 .type = __constant_htons(ETH_P_DEC), 427 .func = lapbeth_rcv, 428 }; 429 430 static struct notifier_block lapbeth_dev_notifier = { 431 .notifier_call = lapbeth_device_event, 432 }; 433 434 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n"; 435 436 static int __init lapbeth_init_driver(void) 437 { 438 dev_add_pack(&lapbeth_packet_type); 439 440 register_netdevice_notifier(&lapbeth_dev_notifier); 441 442 printk(banner); 443 444 return 0; 445 } 446 module_init(lapbeth_init_driver); 447 448 static void __exit lapbeth_cleanup_driver(void) 449 { 450 struct lapbethdev *lapbeth; 451 struct list_head *entry, *tmp; 452 453 dev_remove_pack(&lapbeth_packet_type); 454 unregister_netdevice_notifier(&lapbeth_dev_notifier); 455 456 rtnl_lock(); 457 list_for_each_safe(entry, tmp, &lapbeth_devices) { 458 lapbeth = list_entry(entry, struct lapbethdev, node); 459 460 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