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 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt 24 25 #include <linux/errno.h> 26 #include <linux/types.h> 27 #include <linux/socket.h> 28 #include <linux/in.h> 29 #include <linux/slab.h> 30 #include <linux/kernel.h> 31 #include <linux/string.h> 32 #include <linux/net.h> 33 #include <linux/inet.h> 34 #include <linux/netdevice.h> 35 #include <linux/if_arp.h> 36 #include <linux/skbuff.h> 37 #include <net/sock.h> 38 #include <asm/system.h> 39 #include <asm/uaccess.h> 40 #include <linux/mm.h> 41 #include <linux/interrupt.h> 42 #include <linux/notifier.h> 43 #include <linux/stat.h> 44 #include <linux/netfilter.h> 45 #include <linux/module.h> 46 #include <linux/lapb.h> 47 #include <linux/init.h> 48 49 #include <net/x25device.h> 50 51 static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 52 53 /* If this number is made larger, check that the temporary string buffer 54 * in lapbeth_new_device is large enough to store the probe device name.*/ 55 #define MAXLAPBDEV 100 56 57 struct lapbethdev { 58 struct list_head node; 59 struct net_device *ethdev; /* link to ethernet device */ 60 struct net_device *axdev; /* lapbeth device (lapb#) */ 61 }; 62 63 static LIST_HEAD(lapbeth_devices); 64 65 /* ------------------------------------------------------------------------ */ 66 67 /* 68 * Get the LAPB device for the ethernet device 69 */ 70 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) 71 { 72 struct lapbethdev *lapbeth; 73 74 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) { 75 if (lapbeth->ethdev == dev) 76 return lapbeth; 77 } 78 return NULL; 79 } 80 81 static __inline__ int dev_is_ethdev(struct net_device *dev) 82 { 83 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 84 } 85 86 /* ------------------------------------------------------------------------ */ 87 88 /* 89 * Receive a LAPB frame via an ethernet interface. 90 */ 91 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 92 { 93 int len, err; 94 struct lapbethdev *lapbeth; 95 96 if (dev_net(dev) != &init_net) 97 goto drop; 98 99 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 100 return NET_RX_DROP; 101 102 if (!pskb_may_pull(skb, 2)) 103 goto drop; 104 105 rcu_read_lock(); 106 lapbeth = lapbeth_get_x25_dev(dev); 107 if (!lapbeth) 108 goto drop_unlock; 109 if (!netif_running(lapbeth->axdev)) 110 goto drop_unlock; 111 112 len = skb->data[0] + skb->data[1] * 256; 113 dev->stats.rx_packets++; 114 dev->stats.rx_bytes += len; 115 116 skb_pull(skb, 2); /* Remove the length bytes */ 117 skb_trim(skb, len); /* Set the length of the data */ 118 119 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { 120 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); 121 goto drop_unlock; 122 } 123 out: 124 rcu_read_unlock(); 125 return 0; 126 drop_unlock: 127 kfree_skb(skb); 128 goto out; 129 drop: 130 kfree_skb(skb); 131 return 0; 132 } 133 134 static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) 135 { 136 unsigned char *ptr; 137 138 skb_push(skb, 1); 139 140 if (skb_cow(skb, 1)) 141 return NET_RX_DROP; 142 143 ptr = skb->data; 144 *ptr = X25_IFACE_DATA; 145 146 skb->protocol = x25_type_trans(skb, dev); 147 return netif_rx(skb); 148 } 149 150 /* 151 * Send a LAPB frame via an ethernet interface 152 */ 153 static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, 154 struct net_device *dev) 155 { 156 int err; 157 158 /* 159 * Just to be *really* sure not to send anything if the interface 160 * is down, the ethernet device may have gone. 161 */ 162 if (!netif_running(dev)) 163 goto drop; 164 165 switch (skb->data[0]) { 166 case X25_IFACE_DATA: 167 break; 168 case X25_IFACE_CONNECT: 169 if ((err = lapb_connect_request(dev)) != LAPB_OK) 170 pr_err("lapb_connect_request error: %d\n", err); 171 goto drop; 172 case X25_IFACE_DISCONNECT: 173 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 174 pr_err("lapb_disconnect_request 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 pr_err("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 pr_err("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 pr_err("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 const 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 * open/close a device 273 */ 274 static int lapbeth_open(struct net_device *dev) 275 { 276 int err; 277 278 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { 279 pr_err("lapb_register error: %d\n", err); 280 return -ENODEV; 281 } 282 283 netif_start_queue(dev); 284 return 0; 285 } 286 287 static int lapbeth_close(struct net_device *dev) 288 { 289 int err; 290 291 netif_stop_queue(dev); 292 293 if ((err = lapb_unregister(dev)) != LAPB_OK) 294 pr_err("lapb_unregister error: %d\n", err); 295 296 return 0; 297 } 298 299 /* ------------------------------------------------------------------------ */ 300 301 static const struct net_device_ops lapbeth_netdev_ops = { 302 .ndo_open = lapbeth_open, 303 .ndo_stop = lapbeth_close, 304 .ndo_start_xmit = lapbeth_xmit, 305 .ndo_set_mac_address = lapbeth_set_mac_address, 306 }; 307 308 static void lapbeth_setup(struct net_device *dev) 309 { 310 dev->netdev_ops = &lapbeth_netdev_ops; 311 dev->destructor = free_netdev; 312 dev->type = ARPHRD_X25; 313 dev->hard_header_len = 3; 314 dev->mtu = 1000; 315 dev->addr_len = 0; 316 } 317 318 /* 319 * Setup a new device. 320 */ 321 static int lapbeth_new_device(struct net_device *dev) 322 { 323 struct net_device *ndev; 324 struct lapbethdev *lapbeth; 325 int rc = -ENOMEM; 326 327 ASSERT_RTNL(); 328 329 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 330 lapbeth_setup); 331 if (!ndev) 332 goto out; 333 334 lapbeth = netdev_priv(ndev); 335 lapbeth->axdev = ndev; 336 337 dev_hold(dev); 338 lapbeth->ethdev = dev; 339 340 rc = -EIO; 341 if (register_netdevice(ndev)) 342 goto fail; 343 344 list_add_rcu(&lapbeth->node, &lapbeth_devices); 345 rc = 0; 346 out: 347 return rc; 348 fail: 349 dev_put(dev); 350 free_netdev(ndev); 351 kfree(lapbeth); 352 goto out; 353 } 354 355 /* 356 * Free a lapb network device. 357 */ 358 static void lapbeth_free_device(struct lapbethdev *lapbeth) 359 { 360 dev_put(lapbeth->ethdev); 361 list_del_rcu(&lapbeth->node); 362 unregister_netdevice(lapbeth->axdev); 363 } 364 365 /* 366 * Handle device status changes. 367 * 368 * Called from notifier with RTNL held. 369 */ 370 static int lapbeth_device_event(struct notifier_block *this, 371 unsigned long event, void *ptr) 372 { 373 struct lapbethdev *lapbeth; 374 struct net_device *dev = ptr; 375 376 if (dev_net(dev) != &init_net) 377 return NOTIFY_DONE; 378 379 if (!dev_is_ethdev(dev)) 380 return NOTIFY_DONE; 381 382 switch (event) { 383 case NETDEV_UP: 384 /* New ethernet device -> new LAPB interface */ 385 if (lapbeth_get_x25_dev(dev) == NULL) 386 lapbeth_new_device(dev); 387 break; 388 case NETDEV_DOWN: 389 /* ethernet device closed -> close LAPB interface */ 390 lapbeth = lapbeth_get_x25_dev(dev); 391 if (lapbeth) 392 dev_close(lapbeth->axdev); 393 break; 394 case NETDEV_UNREGISTER: 395 /* ethernet device disappears -> remove LAPB interface */ 396 lapbeth = lapbeth_get_x25_dev(dev); 397 if (lapbeth) 398 lapbeth_free_device(lapbeth); 399 break; 400 } 401 402 return NOTIFY_DONE; 403 } 404 405 /* ------------------------------------------------------------------------ */ 406 407 static struct packet_type lapbeth_packet_type __read_mostly = { 408 .type = cpu_to_be16(ETH_P_DEC), 409 .func = lapbeth_rcv, 410 }; 411 412 static struct notifier_block lapbeth_dev_notifier = { 413 .notifier_call = lapbeth_device_event, 414 }; 415 416 static const char banner[] __initconst = 417 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 418 419 static int __init lapbeth_init_driver(void) 420 { 421 dev_add_pack(&lapbeth_packet_type); 422 423 register_netdevice_notifier(&lapbeth_dev_notifier); 424 425 printk(banner); 426 427 return 0; 428 } 429 module_init(lapbeth_init_driver); 430 431 static void __exit lapbeth_cleanup_driver(void) 432 { 433 struct lapbethdev *lapbeth; 434 struct list_head *entry, *tmp; 435 436 dev_remove_pack(&lapbeth_packet_type); 437 unregister_netdevice_notifier(&lapbeth_dev_notifier); 438 439 rtnl_lock(); 440 list_for_each_safe(entry, tmp, &lapbeth_devices) { 441 lapbeth = list_entry(entry, struct lapbethdev, node); 442 443 dev_put(lapbeth->ethdev); 444 unregister_netdevice(lapbeth->axdev); 445 } 446 rtnl_unlock(); 447 } 448 module_exit(lapbeth_cleanup_driver); 449 450 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 451 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 452 MODULE_LICENSE("GPL"); 453