Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame^] | 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 | struct net_device_stats stats; /* some statistics */ |
| 59 | }; |
| 60 | |
| 61 | static struct list_head lapbeth_devices = LIST_HEAD_INIT(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) |
| 90 | { |
| 91 | int len, err; |
| 92 | struct lapbethdev *lapbeth; |
| 93 | |
| 94 | if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL) |
| 95 | return NET_RX_DROP; |
| 96 | |
| 97 | if (!pskb_may_pull(skb, 2)) |
| 98 | goto drop; |
| 99 | |
| 100 | rcu_read_lock(); |
| 101 | lapbeth = lapbeth_get_x25_dev(dev); |
| 102 | if (!lapbeth) |
| 103 | goto drop_unlock; |
| 104 | if (!netif_running(lapbeth->axdev)) |
| 105 | goto drop_unlock; |
| 106 | |
| 107 | lapbeth->stats.rx_packets++; |
| 108 | |
| 109 | len = skb->data[0] + skb->data[1] * 256; |
| 110 | lapbeth->stats.rx_bytes += len; |
| 111 | |
| 112 | skb_pull(skb, 2); /* Remove the length bytes */ |
| 113 | skb_trim(skb, len); /* Set the length of the data */ |
| 114 | |
| 115 | if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) { |
| 116 | printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err); |
| 117 | goto drop_unlock; |
| 118 | } |
| 119 | out: |
| 120 | rcu_read_unlock(); |
| 121 | return 0; |
| 122 | drop_unlock: |
| 123 | kfree_skb(skb); |
| 124 | goto out; |
| 125 | drop: |
| 126 | kfree_skb(skb); |
| 127 | return 0; |
| 128 | } |
| 129 | |
| 130 | static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb) |
| 131 | { |
| 132 | unsigned char *ptr; |
| 133 | |
| 134 | skb_push(skb, 1); |
| 135 | |
| 136 | if (skb_cow(skb, 1)) |
| 137 | return NET_RX_DROP; |
| 138 | |
| 139 | ptr = skb->data; |
| 140 | *ptr = 0x00; |
| 141 | |
| 142 | skb->protocol = x25_type_trans(skb, dev); |
| 143 | skb->dev->last_rx = jiffies; |
| 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 | lapbeth->stats.tx_packets++; |
| 212 | lapbeth->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 | skb->dev->last_rx = jiffies; |
| 236 | netif_rx(skb); |
| 237 | } |
| 238 | |
| 239 | static void lapbeth_disconnected(struct net_device *dev, int reason) |
| 240 | { |
| 241 | unsigned char *ptr; |
| 242 | struct sk_buff *skb = dev_alloc_skb(1); |
| 243 | |
| 244 | if (!skb) { |
| 245 | printk(KERN_ERR "lapbeth: out of memory\n"); |
| 246 | return; |
| 247 | } |
| 248 | |
| 249 | ptr = skb_put(skb, 1); |
| 250 | *ptr = 0x02; |
| 251 | |
| 252 | skb->protocol = x25_type_trans(skb, dev); |
| 253 | skb->dev->last_rx = jiffies; |
| 254 | netif_rx(skb); |
| 255 | } |
| 256 | |
| 257 | /* |
| 258 | * Statistics |
| 259 | */ |
| 260 | static struct net_device_stats *lapbeth_get_stats(struct net_device *dev) |
| 261 | { |
| 262 | struct lapbethdev *lapbeth = netdev_priv(dev); |
| 263 | return &lapbeth->stats; |
| 264 | } |
| 265 | |
| 266 | /* |
| 267 | * Set AX.25 callsign |
| 268 | */ |
| 269 | static int lapbeth_set_mac_address(struct net_device *dev, void *addr) |
| 270 | { |
| 271 | struct sockaddr *sa = addr; |
| 272 | memcpy(dev->dev_addr, sa->sa_data, dev->addr_len); |
| 273 | return 0; |
| 274 | } |
| 275 | |
| 276 | |
| 277 | static struct lapb_register_struct lapbeth_callbacks = { |
| 278 | .connect_confirmation = lapbeth_connected, |
| 279 | .connect_indication = lapbeth_connected, |
| 280 | .disconnect_confirmation = lapbeth_disconnected, |
| 281 | .disconnect_indication = lapbeth_disconnected, |
| 282 | .data_indication = lapbeth_data_indication, |
| 283 | .data_transmit = lapbeth_data_transmit, |
| 284 | |
| 285 | }; |
| 286 | |
| 287 | /* |
| 288 | * open/close a device |
| 289 | */ |
| 290 | static int lapbeth_open(struct net_device *dev) |
| 291 | { |
| 292 | int err; |
| 293 | |
| 294 | if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) { |
| 295 | printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err); |
| 296 | return -ENODEV; |
| 297 | } |
| 298 | |
| 299 | netif_start_queue(dev); |
| 300 | return 0; |
| 301 | } |
| 302 | |
| 303 | static int lapbeth_close(struct net_device *dev) |
| 304 | { |
| 305 | int err; |
| 306 | |
| 307 | netif_stop_queue(dev); |
| 308 | |
| 309 | if ((err = lapb_unregister(dev)) != LAPB_OK) |
| 310 | printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err); |
| 311 | |
| 312 | return 0; |
| 313 | } |
| 314 | |
| 315 | /* ------------------------------------------------------------------------ */ |
| 316 | |
| 317 | static void lapbeth_setup(struct net_device *dev) |
| 318 | { |
| 319 | dev->hard_start_xmit = lapbeth_xmit; |
| 320 | dev->open = lapbeth_open; |
| 321 | dev->stop = lapbeth_close; |
| 322 | dev->destructor = free_netdev; |
| 323 | dev->set_mac_address = lapbeth_set_mac_address; |
| 324 | dev->get_stats = lapbeth_get_stats; |
| 325 | dev->type = ARPHRD_X25; |
| 326 | dev->hard_header_len = 3; |
| 327 | dev->mtu = 1000; |
| 328 | dev->addr_len = 0; |
| 329 | SET_MODULE_OWNER(dev); |
| 330 | } |
| 331 | |
| 332 | /* |
| 333 | * Setup a new device. |
| 334 | */ |
| 335 | static int lapbeth_new_device(struct net_device *dev) |
| 336 | { |
| 337 | struct net_device *ndev; |
| 338 | struct lapbethdev *lapbeth; |
| 339 | int rc = -ENOMEM; |
| 340 | |
| 341 | ASSERT_RTNL(); |
| 342 | |
| 343 | ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", |
| 344 | lapbeth_setup); |
| 345 | if (!ndev) |
| 346 | goto out; |
| 347 | |
| 348 | lapbeth = netdev_priv(ndev); |
| 349 | lapbeth->axdev = ndev; |
| 350 | |
| 351 | dev_hold(dev); |
| 352 | lapbeth->ethdev = dev; |
| 353 | |
| 354 | rc = dev_alloc_name(ndev, ndev->name); |
| 355 | if (rc < 0) |
| 356 | goto fail; |
| 357 | |
| 358 | rc = -EIO; |
| 359 | if (register_netdevice(ndev)) |
| 360 | goto fail; |
| 361 | |
| 362 | list_add_rcu(&lapbeth->node, &lapbeth_devices); |
| 363 | rc = 0; |
| 364 | out: |
| 365 | return rc; |
| 366 | fail: |
| 367 | dev_put(dev); |
| 368 | free_netdev(ndev); |
| 369 | kfree(lapbeth); |
| 370 | goto out; |
| 371 | } |
| 372 | |
| 373 | /* |
| 374 | * Free a lapb network device. |
| 375 | */ |
| 376 | static void lapbeth_free_device(struct lapbethdev *lapbeth) |
| 377 | { |
| 378 | dev_put(lapbeth->ethdev); |
| 379 | list_del_rcu(&lapbeth->node); |
| 380 | unregister_netdevice(lapbeth->axdev); |
| 381 | } |
| 382 | |
| 383 | /* |
| 384 | * Handle device status changes. |
| 385 | * |
| 386 | * Called from notifier with RTNL held. |
| 387 | */ |
| 388 | static int lapbeth_device_event(struct notifier_block *this, |
| 389 | unsigned long event, void *ptr) |
| 390 | { |
| 391 | struct lapbethdev *lapbeth; |
| 392 | struct net_device *dev = ptr; |
| 393 | |
| 394 | if (!dev_is_ethdev(dev)) |
| 395 | return NOTIFY_DONE; |
| 396 | |
| 397 | switch (event) { |
| 398 | case NETDEV_UP: |
| 399 | /* New ethernet device -> new LAPB interface */ |
| 400 | if (lapbeth_get_x25_dev(dev) == NULL) |
| 401 | lapbeth_new_device(dev); |
| 402 | break; |
| 403 | case NETDEV_DOWN: |
| 404 | /* ethernet device closed -> close LAPB interface */ |
| 405 | lapbeth = lapbeth_get_x25_dev(dev); |
| 406 | if (lapbeth) |
| 407 | dev_close(lapbeth->axdev); |
| 408 | break; |
| 409 | case NETDEV_UNREGISTER: |
| 410 | /* ethernet device disappears -> remove LAPB interface */ |
| 411 | lapbeth = lapbeth_get_x25_dev(dev); |
| 412 | if (lapbeth) |
| 413 | lapbeth_free_device(lapbeth); |
| 414 | break; |
| 415 | } |
| 416 | |
| 417 | return NOTIFY_DONE; |
| 418 | } |
| 419 | |
| 420 | /* ------------------------------------------------------------------------ */ |
| 421 | |
| 422 | static struct packet_type lapbeth_packet_type = { |
| 423 | .type = __constant_htons(ETH_P_DEC), |
| 424 | .func = lapbeth_rcv, |
| 425 | }; |
| 426 | |
| 427 | static struct notifier_block lapbeth_dev_notifier = { |
| 428 | .notifier_call = lapbeth_device_event, |
| 429 | }; |
| 430 | |
| 431 | static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n"; |
| 432 | |
| 433 | static int __init lapbeth_init_driver(void) |
| 434 | { |
| 435 | dev_add_pack(&lapbeth_packet_type); |
| 436 | |
| 437 | register_netdevice_notifier(&lapbeth_dev_notifier); |
| 438 | |
| 439 | printk(banner); |
| 440 | |
| 441 | return 0; |
| 442 | } |
| 443 | module_init(lapbeth_init_driver); |
| 444 | |
| 445 | static void __exit lapbeth_cleanup_driver(void) |
| 446 | { |
| 447 | struct lapbethdev *lapbeth; |
| 448 | struct list_head *entry, *tmp; |
| 449 | |
| 450 | dev_remove_pack(&lapbeth_packet_type); |
| 451 | unregister_netdevice_notifier(&lapbeth_dev_notifier); |
| 452 | |
| 453 | rtnl_lock(); |
| 454 | list_for_each_safe(entry, tmp, &lapbeth_devices) { |
| 455 | lapbeth = list_entry(entry, struct lapbethdev, node); |
| 456 | |
| 457 | unregister_netdevice(lapbeth->axdev); |
| 458 | } |
| 459 | rtnl_unlock(); |
| 460 | } |
| 461 | module_exit(lapbeth_cleanup_driver); |
| 462 | |
| 463 | MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>"); |
| 464 | MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver"); |
| 465 | MODULE_LICENSE("GPL"); |