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");
466
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