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 }; 59 60 static LIST_HEAD(lapbeth_devices); 61 62 /* ------------------------------------------------------------------------ */ 63 64 /* 65 * Get the LAPB device for the ethernet device 66 */ 67 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) 68 { 69 struct lapbethdev *lapbeth; 70 71 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) { 72 if (lapbeth->ethdev == dev) 73 return lapbeth; 74 } 75 return NULL; 76 } 77 78 static __inline__ int dev_is_ethdev(struct net_device *dev) 79 { 80 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 81 } 82 83 /* ------------------------------------------------------------------------ */ 84 85 /* 86 * Receive a LAPB frame via an ethernet interface. 87 */ 88 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 89 { 90 int len, err; 91 struct lapbethdev *lapbeth; 92 93 if (dev_net(dev) != &init_net) 94 goto drop; 95 96 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 97 return NET_RX_DROP; 98 99 if (!pskb_may_pull(skb, 2)) 100 goto drop; 101 102 rcu_read_lock(); 103 lapbeth = lapbeth_get_x25_dev(dev); 104 if (!lapbeth) 105 goto drop_unlock; 106 if (!netif_running(lapbeth->axdev)) 107 goto drop_unlock; 108 109 len = skb->data[0] + skb->data[1] * 256; 110 dev->stats.rx_packets++; 111 dev->stats.rx_bytes += len; 112 113 skb_pull(skb, 2); /* Remove the length bytes */ 114 skb_trim(skb, len); /* Set the length of the data */ 115 116 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 117 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 118 goto drop_unlock; 119 } 120 out: 121 rcu_read_unlock(); 122 return 0; 123 drop_unlock: 124 kfree_skb(skb); 125 goto out; 126 drop: 127 kfree_skb(skb); 128 return 0; 129 } 130 131 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 132 { 133 unsigned char *ptr; 134 135 skb_push(skb, 1); 136 137 if (skb_cow(skb, 1)) 138 return NET_RX_DROP; 139 140 ptr = skb->data; 141 *ptr = 0x00; 142 143 skb->protocol = x25_type_trans(skb, dev); 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 ndev->stats.tx_packets++; 212 ndev->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 netif_rx(skb); 236 } 237 238 static void lapbeth_disconnected(struct net_device *dev, int reason) 239 { 240 unsigned char *ptr; 241 struct sk_buff *skb = dev_alloc_skb(1); 242 243 if (!skb) { 244 printk(KERN_ERR "lapbeth: out of memory\n"); 245 return; 246 } 247 248 ptr = skb_put(skb, 1); 249 *ptr = 0x02; 250 251 skb->protocol = x25_type_trans(skb, dev); 252 netif_rx(skb); 253 } 254 255 /* 256 * Set AX.25 callsign 257 */ 258 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 259 { 260 struct sockaddr *sa = addr; 261 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 262 return 0; 263 } 264 265 266 static struct lapb_register_struct lapbeth_callbacks = { 267 .connect_confirmation = lapbeth_connected, 268 .connect_indication = lapbeth_connected, 269 .disconnect_confirmation = lapbeth_disconnected, 270 .disconnect_indication = lapbeth_disconnected, 271 .data_indication = lapbeth_data_indication, 272 .data_transmit = lapbeth_data_transmit, 273 274 }; 275 276 /* 277 * open/close a device 278 */ 279 static int lapbeth_open(struct net_device *dev) 280 { 281 int err; 282 283 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 284 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 285 return -ENODEV; 286 } 287 288 netif_start_queue(dev); 289 return 0; 290 } 291 292 static int lapbeth_close(struct net_device *dev) 293 { 294 int err; 295 296 netif_stop_queue(dev); 297 298 if ((err = lapb_unregister(dev)) != LAPB_OK) 299 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 300 301 return 0; 302 } 303 304 /* ------------------------------------------------------------------------ */ 305 306 static const struct net_device_ops lapbeth_netdev_ops = { 307 .ndo_open = lapbeth_open, 308 .ndo_stop = lapbeth_close, 309 .ndo_start_xmit = lapbeth_xmit, 310 .ndo_set_mac_address = lapbeth_set_mac_address, 311 }; 312 313 static void lapbeth_setup(struct net_device *dev) 314 { 315 dev->netdev_ops = &lapbeth_netdev_ops; 316 dev->destructor = free_netdev; 317 dev->type = ARPHRD_X25; 318 dev->hard_header_len = 3; 319 dev->mtu = 1000; 320 dev->addr_len = 0; 321 } 322 323 /* 324 * Setup a new device. 325 */ 326 static int lapbeth_new_device(struct net_device *dev) 327 { 328 struct net_device *ndev; 329 struct lapbethdev *lapbeth; 330 int rc = -ENOMEM; 331 332 ASSERT_RTNL(); 333 334 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 335 lapbeth_setup); 336 if (!ndev) 337 goto out; 338 339 lapbeth = netdev_priv(ndev); 340 lapbeth->axdev = ndev; 341 342 dev_hold(dev); 343 lapbeth->ethdev = dev; 344 345 rc = dev_alloc_name(ndev, ndev->name); 346 if (rc < 0) 347 goto fail; 348 349 rc = -EIO; 350 if (register_netdevice(ndev)) 351 goto fail; 352 353 list_add_rcu(&lapbeth->node, &lapbeth_devices); 354 rc = 0; 355 out: 356 return rc; 357 fail: 358 dev_put(dev); 359 free_netdev(ndev); 360 kfree(lapbeth); 361 goto out; 362 } 363 364 /* 365 * Free a lapb network device. 366 */ 367 static void lapbeth_free_device(struct lapbethdev *lapbeth) 368 { 369 dev_put(lapbeth->ethdev); 370 list_del_rcu(&lapbeth->node); 371 unregister_netdevice(lapbeth->axdev); 372 } 373 374 /* 375 * Handle device status changes. 376 * 377 * Called from notifier with RTNL held. 378 */ 379 static int lapbeth_device_event(struct notifier_block *this, 380 unsigned long event, void *ptr) 381 { 382 struct lapbethdev *lapbeth; 383 struct net_device *dev = ptr; 384 385 if (dev_net(dev) != &init_net) 386 return NOTIFY_DONE; 387 388 if (!dev_is_ethdev(dev)) 389 return NOTIFY_DONE; 390 391 switch (event) { 392 case NETDEV_UP: 393 /* New ethernet device -> new LAPB interface */ 394 if (lapbeth_get_x25_dev(dev) == NULL) 395 lapbeth_new_device(dev); 396 break; 397 case NETDEV_DOWN: 398 /* ethernet device closed -> close LAPB interface */ 399 lapbeth = lapbeth_get_x25_dev(dev); 400 if (lapbeth) 401 dev_close(lapbeth->axdev); 402 break; 403 case NETDEV_UNREGISTER: 404 /* ethernet device disappears -> remove LAPB interface */ 405 lapbeth = lapbeth_get_x25_dev(dev); 406 if (lapbeth) 407 lapbeth_free_device(lapbeth); 408 break; 409 } 410 411 return NOTIFY_DONE; 412 } 413 414 /* ------------------------------------------------------------------------ */ 415 416 static struct packet_type lapbeth_packet_type __read_mostly = { 417 .type = cpu_to_be16(ETH_P_DEC), 418 .func = lapbeth_rcv, 419 }; 420 421 static struct notifier_block lapbeth_dev_notifier = { 422 .notifier_call = lapbeth_device_event, 423 }; 424 425 static const char banner[] __initconst = 426 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 427 428 static int __init lapbeth_init_driver(void) 429 { 430 dev_add_pack(&lapbeth_packet_type); 431 432 register_netdevice_notifier(&lapbeth_dev_notifier); 433 434 printk(banner); 435 436 return 0; 437 } 438 module_init(lapbeth_init_driver); 439 440 static void __exit lapbeth_cleanup_driver(void) 441 { 442 struct lapbethdev *lapbeth; 443 struct list_head *entry, *tmp; 444 445 dev_remove_pack(&lapbeth_packet_type); 446 unregister_netdevice_notifier(&lapbeth_dev_notifier); 447 448 rtnl_lock(); 449 list_for_each_safe(entry, tmp, &lapbeth_devices) { 450 lapbeth = list_entry(entry, struct lapbethdev, node); 451 452 dev_put(lapbeth->ethdev); 453 unregister_netdevice(lapbeth->axdev); 454 } 455 rtnl_unlock(); 456 } 457 module_exit(lapbeth_cleanup_driver); 458 459 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 460 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 461 MODULE_LICENSE("GPL"); 462