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/slab.h> 28 #include <linux/kernel.h> 29 #include <linux/string.h> 30 #include <linux/net.h> 31 #include <linux/inet.h> 32 #include <linux/netdevice.h> 33 #include <linux/if_arp.h> 34 #include <linux/skbuff.h> 35 #include <net/sock.h> 36 #include <asm/system.h> 37 #include <asm/uaccess.h> 38 #include <linux/mm.h> 39 #include <linux/interrupt.h> 40 #include <linux/notifier.h> 41 #include <linux/stat.h> 42 #include <linux/netfilter.h> 43 #include <linux/module.h> 44 #include <linux/lapb.h> 45 #include <linux/init.h> 46 47 #include <net/x25device.h> 48 49 static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 50 51 /* If this number is made larger, check that the temporary string buffer 52 * in lapbeth_new_device is large enough to store the probe device name.*/ 53 #define MAXLAPBDEV 100 54 55 struct lapbethdev { 56 struct list_head node; 57 struct net_device *ethdev; /* link to ethernet device */ 58 struct net_device *axdev; /* lapbeth device (lapb#) */ 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 len = skb->data[0] + skb->data[1] * 256; 111 dev->stats.rx_packets++; 112 dev->stats.rx_bytes += len; 113 114 skb_pull(skb, 2); /* Remove the length bytes */ 115 skb_trim(skb, len); /* Set the length of the data */ 116 117 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 118 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 119 goto drop_unlock; 120 } 121 out: 122 rcu_read_unlock(); 123 return 0; 124 drop_unlock: 125 kfree_skb(skb); 126 goto out; 127 drop: 128 kfree_skb(skb); 129 return 0; 130 } 131 132 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 133 { 134 unsigned char *ptr; 135 136 skb_push(skb, 1); 137 138 if (skb_cow(skb, 1)) 139 return NET_RX_DROP; 140 141 ptr = skb->data; 142 *ptr = X25_IFACE_DATA; 143 144 skb->protocol = x25_type_trans(skb, dev); 145 return netif_rx(skb); 146 } 147 148 /* 149 * Send a LAPB frame via an ethernet interface 150 */ 151 static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, 152 struct net_device *dev) 153 { 154 int err; 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 switch (skb->data[0]) { 164 case X25_IFACE_DATA: 165 break; 166 case X25_IFACE_CONNECT: 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; 171 case X25_IFACE_DISCONNECT: 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; 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 goto drop; 185 } 186 out: 187 return NETDEV_TX_OK; 188 drop: 189 kfree_skb(skb); 190 goto out; 191 } 192 193 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 194 { 195 struct lapbethdev *lapbeth = netdev_priv(ndev); 196 unsigned char *ptr; 197 struct net_device *dev; 198 int size = skb->len; 199 200 skb->protocol = htons(ETH_P_X25); 201 202 ptr = skb_push(skb, 2); 203 204 *ptr++ = size % 256; 205 *ptr++ = size / 256; 206 207 ndev->stats.tx_packets++; 208 ndev->stats.tx_bytes += size; 209 210 skb->dev = dev = lapbeth->ethdev; 211 212 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 213 214 dev_queue_xmit(skb); 215 } 216 217 static void lapbeth_connected(struct net_device *dev, int reason) 218 { 219 unsigned char *ptr; 220 struct sk_buff *skb = dev_alloc_skb(1); 221 222 if (!skb) { 223 printk(KERN_ERR "lapbeth: out of memory\n"); 224 return; 225 } 226 227 ptr = skb_put(skb, 1); 228 *ptr = X25_IFACE_CONNECT; 229 230 skb->protocol = x25_type_trans(skb, dev); 231 netif_rx(skb); 232 } 233 234 static void lapbeth_disconnected(struct net_device *dev, int reason) 235 { 236 unsigned char *ptr; 237 struct sk_buff *skb = dev_alloc_skb(1); 238 239 if (!skb) { 240 printk(KERN_ERR "lapbeth: out of memory\n"); 241 return; 242 } 243 244 ptr = skb_put(skb, 1); 245 *ptr = X25_IFACE_DISCONNECT; 246 247 skb->protocol = x25_type_trans(skb, dev); 248 netif_rx(skb); 249 } 250 251 /* 252 * Set AX.25 callsign 253 */ 254 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 255 { 256 struct sockaddr *sa = addr; 257 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 258 return 0; 259 } 260 261 262 static struct lapb_register_struct lapbeth_callbacks = { 263 .connect_confirmation = lapbeth_connected, 264 .connect_indication = lapbeth_connected, 265 .disconnect_confirmation = lapbeth_disconnected, 266 .disconnect_indication = lapbeth_disconnected, 267 .data_indication = lapbeth_data_indication, 268 .data_transmit = lapbeth_data_transmit, 269 270 }; 271 272 /* 273 * open/close a device 274 */ 275 static int lapbeth_open(struct net_device *dev) 276 { 277 int err; 278 279 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 280 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); 281 return -ENODEV; 282 } 283 284 netif_start_queue(dev); 285 return 0; 286 } 287 288 static int lapbeth_close(struct net_device *dev) 289 { 290 int err; 291 292 netif_stop_queue(dev); 293 294 if ((err = lapb_unregister(dev)) != LAPB_OK) 295 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); 296 297 return 0; 298 } 299 300 /* ------------------------------------------------------------------------ */ 301 302 static const struct net_device_ops lapbeth_netdev_ops = { 303 .ndo_open = lapbeth_open, 304 .ndo_stop = lapbeth_close, 305 .ndo_start_xmit = lapbeth_xmit, 306 .ndo_set_mac_address = lapbeth_set_mac_address, 307 }; 308 309 static void lapbeth_setup(struct net_device *dev) 310 { 311 dev->netdev_ops = &lapbeth_netdev_ops; 312 dev->destructor = free_netdev; 313 dev->type = ARPHRD_X25; 314 dev->hard_header_len = 3; 315 dev->mtu = 1000; 316 dev->addr_len = 0; 317 } 318 319 /* 320 * Setup a new device. 321 */ 322 static int lapbeth_new_device(struct net_device *dev) 323 { 324 struct net_device *ndev; 325 struct lapbethdev *lapbeth; 326 int rc = -ENOMEM; 327 328 ASSERT_RTNL(); 329 330 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 331 lapbeth_setup); 332 if (!ndev) 333 goto out; 334 335 lapbeth = netdev_priv(ndev); 336 lapbeth->axdev = ndev; 337 338 dev_hold(dev); 339 lapbeth->ethdev = dev; 340 341 rc = dev_alloc_name(ndev, ndev->name); 342 if (rc < 0) 343 goto fail; 344 345 rc = -EIO; 346 if (register_netdevice(ndev)) 347 goto fail; 348 349 list_add_rcu(&lapbeth->node, &lapbeth_devices); 350 rc = 0; 351 out: 352 return rc; 353 fail: 354 dev_put(dev); 355 free_netdev(ndev); 356 kfree(lapbeth); 357 goto out; 358 } 359 360 /* 361 * Free a lapb network device. 362 */ 363 static void lapbeth_free_device(struct lapbethdev *lapbeth) 364 { 365 dev_put(lapbeth->ethdev); 366 list_del_rcu(&lapbeth->node); 367 unregister_netdevice(lapbeth->axdev); 368 } 369 370 /* 371 * Handle device status changes. 372 * 373 * Called from notifier with RTNL held. 374 */ 375 static int lapbeth_device_event(struct notifier_block *this, 376 unsigned long event, void *ptr) 377 { 378 struct lapbethdev *lapbeth; 379 struct net_device *dev = ptr; 380 381 if (dev_net(dev) != &init_net) 382 return NOTIFY_DONE; 383 384 if (!dev_is_ethdev(dev)) 385 return NOTIFY_DONE; 386 387 switch (event) { 388 case NETDEV_UP: 389 /* New ethernet device -> new LAPB interface */ 390 if (lapbeth_get_x25_dev(dev) == NULL) 391 lapbeth_new_device(dev); 392 break; 393 case NETDEV_DOWN: 394 /* ethernet device closed -> close LAPB interface */ 395 lapbeth = lapbeth_get_x25_dev(dev); 396 if (lapbeth) 397 dev_close(lapbeth->axdev); 398 break; 399 case NETDEV_UNREGISTER: 400 /* ethernet device disappears -> remove LAPB interface */ 401 lapbeth = lapbeth_get_x25_dev(dev); 402 if (lapbeth) 403 lapbeth_free_device(lapbeth); 404 break; 405 } 406 407 return NOTIFY_DONE; 408 } 409 410 /* ------------------------------------------------------------------------ */ 411 412 static struct packet_type lapbeth_packet_type __read_mostly = { 413 .type = cpu_to_be16(ETH_P_DEC), 414 .func = lapbeth_rcv, 415 }; 416 417 static struct notifier_block lapbeth_dev_notifier = { 418 .notifier_call = lapbeth_device_event, 419 }; 420 421 static const char banner[] __initconst = 422 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 423 424 static int __init lapbeth_init_driver(void) 425 { 426 dev_add_pack(&lapbeth_packet_type); 427 428 register_netdevice_notifier(&lapbeth_dev_notifier); 429 430 printk(banner); 431 432 return 0; 433 } 434 module_init(lapbeth_init_driver); 435 436 static void __exit lapbeth_cleanup_driver(void) 437 { 438 struct lapbethdev *lapbeth; 439 struct list_head *entry, *tmp; 440 441 dev_remove_pack(&lapbeth_packet_type); 442 unregister_netdevice_notifier(&lapbeth_dev_notifier); 443 444 rtnl_lock(); 445 list_for_each_safe(entry, tmp, &lapbeth_devices) { 446 lapbeth = list_entry(entry, struct lapbethdev, node); 447 448 dev_put(lapbeth->ethdev); 449 unregister_netdevice(lapbeth->axdev); 450 } 451 rtnl_unlock(); 452 } 453 module_exit(lapbeth_cleanup_driver); 454 455 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 456 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 457 MODULE_LICENSE("GPL"); 458