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/uaccess.h> 39 #include <linux/mm.h> 40 #include <linux/interrupt.h> 41 #include <linux/notifier.h> 42 #include <linux/stat.h> 43 #include <linux/netfilter.h> 44 #include <linux/module.h> 45 #include <linux/lapb.h> 46 #include <linux/init.h> 47 48 #include <net/x25device.h> 49 50 static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }; 51 52 /* If this number is made larger, check that the temporary string buffer 53 * in lapbeth_new_device is large enough to store the probe device name.*/ 54 #define MAXLAPBDEV 100 55 56 struct lapbethdev { 57 struct list_head node; 58 struct net_device *ethdev; /* link to ethernet device */ 59 struct net_device *axdev; /* lapbeth device (lapb#) */ 60 }; 61 62 static LIST_HEAD(lapbeth_devices); 63 64 /* ------------------------------------------------------------------------ */ 65 66 /* 67 * Get the LAPB device for the ethernet device 68 */ 69 static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev) 70 { 71 struct lapbethdev *lapbeth; 72 73 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) { 74 if (lapbeth->ethdev == dev) 75 return lapbeth; 76 } 77 return NULL; 78 } 79 80 static __inline__ int dev_is_ethdev(struct net_device *dev) 81 { 82 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5); 83 } 84 85 /* ------------------------------------------------------------------------ */ 86 87 /* 88 * Receive a LAPB frame via an ethernet interface. 89 */ 90 static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev) 91 { 92 int len, err; 93 struct lapbethdev *lapbeth; 94 95 if (dev_net(dev) != &init_net) 96 goto drop; 97 98 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) 99 return NET_RX_DROP; 100 101 if (!pskb_may_pull(skb, 2)) 102 goto drop; 103 104 rcu_read_lock(); 105 lapbeth = lapbeth_get_x25_dev(dev); 106 if (!lapbeth) 107 goto drop_unlock; 108 if (!netif_running(lapbeth->axdev)) 109 goto drop_unlock; 110 111 len = skb->data[0] + skb->data[1] * 256; 112 dev->stats.rx_packets++; 113 dev->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 = X25_IFACE_DATA; 144 145 skb->protocol = x25_type_trans(skb, dev); 146 return netif_rx(skb); 147 } 148 149 /* 150 * Send a LAPB frame via an ethernet interface 151 */ 152 static netdev_tx_t lapbeth_xmit(struct sk_buff *skb, 153 struct net_device *dev) 154 { 155 int err; 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 switch (skb->data[0]) { 165 case X25_IFACE_DATA: 166 break; 167 case X25_IFACE_CONNECT: 168 if ((err = lapb_connect_request(dev)) != LAPB_OK) 169 pr_err("lapb_connect_request error: %d\n", err); 170 goto drop; 171 case X25_IFACE_DISCONNECT: 172 if ((err = lapb_disconnect_request(dev)) != LAPB_OK) 173 pr_err("lapb_disconnect_request err: %d\n", err); 174 /* Fall thru */ 175 default: 176 goto drop; 177 } 178 179 skb_pull(skb, 1); 180 181 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) { 182 pr_err("lapb_data_request error - %d\n", err); 183 goto drop; 184 } 185 out: 186 return NETDEV_TX_OK; 187 drop: 188 kfree_skb(skb); 189 goto out; 190 } 191 192 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb) 193 { 194 struct lapbethdev *lapbeth = netdev_priv(ndev); 195 unsigned char *ptr; 196 struct net_device *dev; 197 int size = skb->len; 198 199 skb->protocol = htons(ETH_P_X25); 200 201 ptr = skb_push(skb, 2); 202 203 *ptr++ = size % 256; 204 *ptr++ = size / 256; 205 206 ndev->stats.tx_packets++; 207 ndev->stats.tx_bytes += size; 208 209 skb->dev = dev = lapbeth->ethdev; 210 211 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0); 212 213 dev_queue_xmit(skb); 214 } 215 216 static void lapbeth_connected(struct net_device *dev, int reason) 217 { 218 unsigned char *ptr; 219 struct sk_buff *skb = dev_alloc_skb(1); 220 221 if (!skb) { 222 pr_err("out of memory\n"); 223 return; 224 } 225 226 ptr = skb_put(skb, 1); 227 *ptr = X25_IFACE_CONNECT; 228 229 skb->protocol = x25_type_trans(skb, dev); 230 netif_rx(skb); 231 } 232 233 static void lapbeth_disconnected(struct net_device *dev, int reason) 234 { 235 unsigned char *ptr; 236 struct sk_buff *skb = dev_alloc_skb(1); 237 238 if (!skb) { 239 pr_err("out of memory\n"); 240 return; 241 } 242 243 ptr = skb_put(skb, 1); 244 *ptr = X25_IFACE_DISCONNECT; 245 246 skb->protocol = x25_type_trans(skb, dev); 247 netif_rx(skb); 248 } 249 250 /* 251 * Set AX.25 callsign 252 */ 253 static int lapbeth_set_mac_address(struct net_device *dev, void *addr) 254 { 255 struct sockaddr *sa = addr; 256 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); 257 return 0; 258 } 259 260 261 static const struct lapb_register_struct lapbeth_callbacks = { 262 .connect_confirmation = lapbeth_connected, 263 .connect_indication = lapbeth_connected, 264 .disconnect_confirmation = lapbeth_disconnected, 265 .disconnect_indication = lapbeth_disconnected, 266 .data_indication = lapbeth_data_indication, 267 .data_transmit = lapbeth_data_transmit, 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 pr_err("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 pr_err("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 = -EIO; 340 if (register_netdevice(ndev)) 341 goto fail; 342 343 list_add_rcu(&lapbeth->node, &lapbeth_devices); 344 rc = 0; 345 out: 346 return rc; 347 fail: 348 dev_put(dev); 349 free_netdev(ndev); 350 kfree(lapbeth); 351 goto out; 352 } 353 354 /* 355 * Free a lapb network device. 356 */ 357 static void lapbeth_free_device(struct lapbethdev *lapbeth) 358 { 359 dev_put(lapbeth->ethdev); 360 list_del_rcu(&lapbeth->node); 361 unregister_netdevice(lapbeth->axdev); 362 } 363 364 /* 365 * Handle device status changes. 366 * 367 * Called from notifier with RTNL held. 368 */ 369 static int lapbeth_device_event(struct notifier_block *this, 370 unsigned long event, void *ptr) 371 { 372 struct lapbethdev *lapbeth; 373 struct net_device *dev = ptr; 374 375 if (dev_net(dev) != &init_net) 376 return NOTIFY_DONE; 377 378 if (!dev_is_ethdev(dev)) 379 return NOTIFY_DONE; 380 381 switch (event) { 382 case NETDEV_UP: 383 /* New ethernet device -> new LAPB interface */ 384 if (lapbeth_get_x25_dev(dev) == NULL) 385 lapbeth_new_device(dev); 386 break; 387 case NETDEV_DOWN: 388 /* ethernet device closed -> close LAPB interface */ 389 lapbeth = lapbeth_get_x25_dev(dev); 390 if (lapbeth) 391 dev_close(lapbeth->axdev); 392 break; 393 case NETDEV_UNREGISTER: 394 /* ethernet device disappears -> remove LAPB interface */ 395 lapbeth = lapbeth_get_x25_dev(dev); 396 if (lapbeth) 397 lapbeth_free_device(lapbeth); 398 break; 399 } 400 401 return NOTIFY_DONE; 402 } 403 404 /* ------------------------------------------------------------------------ */ 405 406 static struct packet_type lapbeth_packet_type __read_mostly = { 407 .type = cpu_to_be16(ETH_P_DEC), 408 .func = lapbeth_rcv, 409 }; 410 411 static struct notifier_block lapbeth_dev_notifier = { 412 .notifier_call = lapbeth_device_event, 413 }; 414 415 static const char banner[] __initconst = 416 KERN_INFO "LAPB Ethernet driver version 0.02\n"; 417 418 static int __init lapbeth_init_driver(void) 419 { 420 dev_add_pack(&lapbeth_packet_type); 421 422 register_netdevice_notifier(&lapbeth_dev_notifier); 423 424 printk(banner); 425 426 return 0; 427 } 428 module_init(lapbeth_init_driver); 429 430 static void __exit lapbeth_cleanup_driver(void) 431 { 432 struct lapbethdev *lapbeth; 433 struct list_head *entry, *tmp; 434 435 dev_remove_pack(&lapbeth_packet_type); 436 unregister_netdevice_notifier(&lapbeth_dev_notifier); 437 438 rtnl_lock(); 439 list_for_each_safe(entry, tmp, &lapbeth_devices) { 440 lapbeth = list_entry(entry, struct lapbethdev, node); 441 442 dev_put(lapbeth->ethdev); 443 unregister_netdevice(lapbeth->axdev); 444 } 445 rtnl_unlock(); 446 } 447 module_exit(lapbeth_cleanup_driver); 448 449 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); 450 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); 451 MODULE_LICENSE("GPL"); 452