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; 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 switch (skb->data[0]) { 162 case 0x00: 163 break; 164 case 0x01: 165 if ((err = lapb_connect_request(dev)) != LAPB_OK) 166 printk(KERN_ERR "lapbeth: lapb_connect_request " 167 "error: %d\n", err); 168 goto drop; 169 case 0x02: 170 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 171 printk(KERN_ERR "lapbeth: lapb_disconnect_request " 172 "err: %d\n", err); 173 /* Fall thru */ 174 default: 175 goto drop; 176 } 177 178 skb_pull(skb, 1); 179 180 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 181 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err); 182 goto drop; 183 } 184 out: 185 return NETDEV_TX_OK; 186 drop: 187 kfree_skb(skb); 188 goto out; 189 } 190 191 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 192 { 193 struct lapbethdev *lapbeth = netdev_priv(ndev); 194 unsigned char *ptr; 195 struct net_device *dev; 196 int size = skb->len; 197 198 skb->protocol = htons(ETH_P_X25); 199 200 ptr = skb_push(skb, 2); 201 202 *ptr++ = size % 256; 203 *ptr++ = size / 256; 204 205 ndev->stats.tx_packets++; 206 ndev->stats.tx_bytes += size; 207 208 skb->dev = dev = lapbeth->ethdev; 209 210 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 211 212 dev_queue_xmit(skb); 213 } 214 215 static void lapbeth_connected(struct net_device *dev, int reason) 216 { 217 unsigned char *ptr; 218 struct sk_buff *skb = dev_alloc_skb(1); 219 220 if (!skb) { 221 printk(KERN_ERR "lapbeth: out of memory\n"); 222 return; 223 } 224 225 ptr = skb_put(skb, 1); 226 *ptr = 0x01; 227 228 skb->protocol = x25_type_trans(skb, dev); 229 netif_rx(skb); 230 } 231 232 static void lapbeth_disconnected(struct net_device *dev, int reason) 233 { 234 unsigned char *ptr; 235 struct sk_buff *skb = dev_alloc_skb(1); 236 237 if (!skb) { 238 printk(KERN_ERR "lapbeth: out of memory\n"); 239 return; 240 } 241 242 ptr = skb_put(skb, 1); 243 *ptr = 0x02; 244 245 skb->protocol = x25_type_trans(skb, dev); 246 netif_rx(skb); 247 } 248 249 /* 250 * Set AX.25 callsign 251 */ 252 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 253 { 254 struct sockaddr *sa = addr; 255 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 256 return 0; 257 } 258 259 260 static struct lapb_register_struct lapbeth_callbacks = { 261 .connect_confirmation = lapbeth_connected, 262 .connect_indication = lapbeth_connected, 263 .disconnect_confirmation = lapbeth_disconnected, 264 .disconnect_indication = lapbeth_disconnected, 265 .data_indication = lapbeth_data_indication, 266 .data_transmit = lapbeth_data_transmit, 267 268 }; 269 270 /* 271 * open/close a device 272 */ 273 static int lapbeth_open(struct net_device *dev) 274 { 275 int err; 276 277 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 278 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 279 return -ENODEV; 280 } 281 282 netif_start_queue(dev); 283 return 0; 284 } 285 286 static int lapbeth_close(struct net_device *dev) 287 { 288 int err; 289 290 netif_stop_queue(dev); 291 292 if ((err = lapb_unregister(dev)) != LAPB_OK) 293 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 294 295 return 0; 296 } 297 298 /* ------------------------------------------------------------------------ */ 299 300 static const struct net_device_ops lapbeth_netdev_ops = { 301 .ndo_open = lapbeth_open, 302 .ndo_stop = lapbeth_close, 303 .ndo_start_xmit = lapbeth_xmit, 304 .ndo_set_mac_address = lapbeth_set_mac_address, 305 }; 306 307 static void lapbeth_setup(struct net_device *dev) 308 { 309 dev->netdev_ops = &lapbeth_netdev_ops; 310 dev->destructor = free_netdev; 311 dev->type = ARPHRD_X25; 312 dev->hard_header_len = 3; 313 dev->mtu = 1000; 314 dev->addr_len = 0; 315 } 316 317 /* 318 * Setup a new device. 319 */ 320 static int lapbeth_new_device(struct net_device *dev) 321 { 322 struct net_device *ndev; 323 struct lapbethdev *lapbeth; 324 int rc = -ENOMEM; 325 326 ASSERT_RTNL(); 327 328 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 329 lapbeth_setup); 330 if (!ndev) 331 goto out; 332 333 lapbeth = netdev_priv(ndev); 334 lapbeth->axdev = ndev; 335 336 dev_hold(dev); 337 lapbeth->ethdev = dev; 338 339 rc = dev_alloc_name(ndev, ndev->name); 340 if (rc < 0) 341 goto fail; 342 343 rc = -EIO; 344 if (register_netdevice(ndev)) 345 goto fail; 346 347 list_add_rcu(&lapbeth->node, &lapbeth_devices); 348 rc = 0; 349 out: 350 return rc; 351 fail: 352 dev_put(dev); 353 free_netdev(ndev); 354 kfree(lapbeth); 355 goto out; 356 } 357 358 /* 359 * Free a lapb network device. 360 */ 361 static void lapbeth_free_device(struct lapbethdev *lapbeth) 362 { 363 dev_put(lapbeth->ethdev); 364 list_del_rcu(&lapbeth->node); 365 unregister_netdevice(lapbeth->axdev); 366 } 367 368 /* 369 * Handle device status changes. 370 * 371 * Called from notifier with RTNL held. 372 */ 373 static int lapbeth_device_event(struct notifier_block *this, 374 unsigned long event, void *ptr) 375 { 376 struct lapbethdev *lapbeth; 377 struct net_device *dev = ptr; 378 379 if (dev_net(dev) != &init_net) 380 return NOTIFY_DONE; 381 382 if (!dev_is_ethdev(dev)) 383 return NOTIFY_DONE; 384 385 switch (event) { 386 case NETDEV_UP: 387 /* New ethernet device -> new LAPB interface */ 388 if (lapbeth_get_x25_dev(dev) == NULL) 389 lapbeth_new_device(dev); 390 break; 391 case NETDEV_DOWN: 392 /* ethernet device closed -> close LAPB interface */ 393 lapbeth = lapbeth_get_x25_dev(dev); 394 if (lapbeth) 395 dev_close(lapbeth->axdev); 396 break; 397 case NETDEV_UNREGISTER: 398 /* ethernet device disappears -> remove LAPB interface */ 399 lapbeth = lapbeth_get_x25_dev(dev); 400 if (lapbeth) 401 lapbeth_free_device(lapbeth); 402 break; 403 } 404 405 return NOTIFY_DONE; 406 } 407 408 /* ------------------------------------------------------------------------ */ 409 410 static struct packet_type lapbeth_packet_type __read_mostly = { 411 .type = cpu_to_be16(ETH_P_DEC), 412 .func = lapbeth_rcv, 413 }; 414 415 static struct notifier_block lapbeth_dev_notifier = { 416 .notifier_call = lapbeth_device_event, 417 }; 418 419 static const char banner[] __initconst = 420 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 421 422 static int __init lapbeth_init_driver(void) 423 { 424 dev_add_pack(&lapbeth_packet_type); 425 426 register_netdevice_notifier(&lapbeth_dev_notifier); 427 428 printk(banner); 429 430 return 0; 431 } 432 module_init(lapbeth_init_driver); 433 434 static void __exit lapbeth_cleanup_driver(void) 435 { 436 struct lapbethdev *lapbeth; 437 struct list_head *entry, *tmp; 438 439 dev_remove_pack(&lapbeth_packet_type); 440 unregister_netdevice_notifier(&lapbeth_dev_notifier); 441 442 rtnl_lock(); 443 list_for_each_safe(entry, tmp, &lapbeth_devices) { 444 lapbeth = list_entry(entry, struct lapbethdev, node); 445 446 dev_put(lapbeth->ethdev); 447 unregister_netdevice(lapbeth->axdev); 448 } 449 rtnl_unlock(); 450 } 451 module_exit(lapbeth_cleanup_driver); 452 453 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 454 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 455 MODULE_LICENSE("GPL"); 456