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 LIST_HEAD(lapbeth_devices);
62
63 /* ------------------------------------------------------------------------ */
64
65 /*
66 * Get the LAPB device for the ethernet device
67 */
lapbeth_get_x25_dev(struct net_device * dev)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
dev_is_ethdev(struct net_device * dev)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 */
lapbeth_rcv(struct sk_buff * skb,struct net_device * dev,struct packet_type * ptype,struct net_device * orig_dev)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 lapbeth->stats.rx_packets++;
111
112 len = skb->data[0] + skb->data[1] * 256;
113 lapbeth->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
lapbeth_data_indication(struct net_device * dev,struct sk_buff * skb)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 = 0x00;
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 */
lapbeth_xmit(struct sk_buff * skb,struct net_device * dev)152 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
153 {
154 int err = -ENODEV;
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
164 switch (skb->data[0]) {
165 case 0x00:
166 err = 0;
167 break;
168 case 0x01:
169 if ((err = lapb_connect_request(dev)) != LAPB_OK)
170 printk(KERN_ERR "lapbeth: lapb_connect_request "
171 "error: %d\n", err);
172 goto drop_ok;
173 case 0x02:
174 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
175 printk(KERN_ERR "lapbeth: lapb_disconnect_request "
176 "err: %d\n", err);
177 /* Fall thru */
178 default:
179 goto drop_ok;
180 }
181
182 skb_pull(skb, 1);
183
184 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
185 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
186 err = -ENOMEM;
187 goto drop;
188 }
189 err = 0;
190 out:
191 return err;
192 drop_ok:
193 err = 0;
194 drop:
195 kfree_skb(skb);
196 goto out;
197 }
198
lapbeth_data_transmit(struct net_device * ndev,struct sk_buff * skb)199 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
200 {
201 struct lapbethdev *lapbeth = netdev_priv(ndev);
202 unsigned char *ptr;
203 struct net_device *dev;
204 int size = skb->len;
205
206 skb->protocol = htons(ETH_P_X25);
207
208 ptr = skb_push(skb, 2);
209
210 *ptr++ = size % 256;
211 *ptr++ = size / 256;
212
213 lapbeth->stats.tx_packets++;
214 lapbeth->stats.tx_bytes += size;
215
216 skb->dev = dev = lapbeth->ethdev;
217
218 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
219
220 dev_queue_xmit(skb);
221 }
222
lapbeth_connected(struct net_device * dev,int reason)223 static void lapbeth_connected(struct net_device *dev, int reason)
224 {
225 unsigned char *ptr;
226 struct sk_buff *skb = dev_alloc_skb(1);
227
228 if (!skb) {
229 printk(KERN_ERR "lapbeth: out of memory\n");
230 return;
231 }
232
233 ptr = skb_put(skb, 1);
234 *ptr = 0x01;
235
236 skb->protocol = x25_type_trans(skb, dev);
237 netif_rx(skb);
238 }
239
lapbeth_disconnected(struct net_device * dev,int reason)240 static void lapbeth_disconnected(struct net_device *dev, int reason)
241 {
242 unsigned char *ptr;
243 struct sk_buff *skb = dev_alloc_skb(1);
244
245 if (!skb) {
246 printk(KERN_ERR "lapbeth: out of memory\n");
247 return;
248 }
249
250 ptr = skb_put(skb, 1);
251 *ptr = 0x02;
252
253 skb->protocol = x25_type_trans(skb, dev);
254 netif_rx(skb);
255 }
256
257 /*
258 * Statistics
259 */
lapbeth_get_stats(struct net_device * dev)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 */
lapbeth_set_mac_address(struct net_device * dev,void * addr)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 */
lapbeth_open(struct net_device * dev)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
lapbeth_close(struct net_device * dev)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
lapbeth_setup(struct net_device * dev)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 }
330
331 /*
332 * Setup a new device.
333 */
lapbeth_new_device(struct net_device * dev)334 static int lapbeth_new_device(struct net_device *dev)
335 {
336 struct net_device *ndev;
337 struct lapbethdev *lapbeth;
338 int rc = -ENOMEM;
339
340 ASSERT_RTNL();
341
342 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
343 lapbeth_setup);
344 if (!ndev)
345 goto out;
346
347 lapbeth = netdev_priv(ndev);
348 lapbeth->axdev = ndev;
349
350 dev_hold(dev);
351 lapbeth->ethdev = dev;
352
353 rc = dev_alloc_name(ndev, ndev->name);
354 if (rc < 0)
355 goto fail;
356
357 rc = -EIO;
358 if (register_netdevice(ndev))
359 goto fail;
360
361 list_add_rcu(&lapbeth->node, &lapbeth_devices);
362 rc = 0;
363 out:
364 return rc;
365 fail:
366 dev_put(dev);
367 free_netdev(ndev);
368 kfree(lapbeth);
369 goto out;
370 }
371
372 /*
373 * Free a lapb network device.
374 */
lapbeth_free_device(struct lapbethdev * lapbeth)375 static void lapbeth_free_device(struct lapbethdev *lapbeth)
376 {
377 dev_put(lapbeth->ethdev);
378 list_del_rcu(&lapbeth->node);
379 unregister_netdevice(lapbeth->axdev);
380 }
381
382 /*
383 * Handle device status changes.
384 *
385 * Called from notifier with RTNL held.
386 */
lapbeth_device_event(struct notifier_block * this,unsigned long event,void * ptr)387 static int lapbeth_device_event(struct notifier_block *this,
388 unsigned long event, void *ptr)
389 {
390 struct lapbethdev *lapbeth;
391 struct net_device *dev = ptr;
392
393 if (dev_net(dev) != &init_net)
394 return NOTIFY_DONE;
395
396 if (!dev_is_ethdev(dev))
397 return NOTIFY_DONE;
398
399 switch (event) {
400 case NETDEV_UP:
401 /* New ethernet device -> new LAPB interface */
402 if (lapbeth_get_x25_dev(dev) == NULL)
403 lapbeth_new_device(dev);
404 break;
405 case NETDEV_DOWN:
406 /* ethernet device closed -> close LAPB interface */
407 lapbeth = lapbeth_get_x25_dev(dev);
408 if (lapbeth)
409 dev_close(lapbeth->axdev);
410 break;
411 case NETDEV_UNREGISTER:
412 /* ethernet device disappears -> remove LAPB interface */
413 lapbeth = lapbeth_get_x25_dev(dev);
414 if (lapbeth)
415 lapbeth_free_device(lapbeth);
416 break;
417 }
418
419 return NOTIFY_DONE;
420 }
421
422 /* ------------------------------------------------------------------------ */
423
424 static struct packet_type lapbeth_packet_type = {
425 .type = __constant_htons(ETH_P_DEC),
426 .func = lapbeth_rcv,
427 };
428
429 static struct notifier_block lapbeth_dev_notifier = {
430 .notifier_call = lapbeth_device_event,
431 };
432
433 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
434
lapbeth_init_driver(void)435 static int __init lapbeth_init_driver(void)
436 {
437 dev_add_pack(&lapbeth_packet_type);
438
439 register_netdevice_notifier(&lapbeth_dev_notifier);
440
441 printk(banner);
442
443 return 0;
444 }
445 module_init(lapbeth_init_driver);
446
lapbeth_cleanup_driver(void)447 static void __exit lapbeth_cleanup_driver(void)
448 {
449 struct lapbethdev *lapbeth;
450 struct list_head *entry, *tmp;
451
452 dev_remove_pack(&lapbeth_packet_type);
453 unregister_netdevice_notifier(&lapbeth_dev_notifier);
454
455 rtnl_lock();
456 list_for_each_safe(entry, tmp, &lapbeth_devices) {
457 lapbeth = list_entry(entry, struct lapbethdev, node);
458
459 dev_put(lapbeth->ethdev);
460 unregister_netdevice(lapbeth->axdev);
461 }
462 rtnl_unlock();
463 }
464 module_exit(lapbeth_cleanup_driver);
465
466 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
467 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
468 MODULE_LICENSE("GPL");
469