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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
48static 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
54struct lapbethdev {
55 struct list_head node;
56 struct net_device *ethdev; /* link to ethernet device */
57 struct net_device *axdev; /* lapbeth device (lapb#) */
58};
59
60static LIST_HEAD(lapbeth_devices);
61
62/* ------------------------------------------------------------------------ */
63
64/*
65 * Get the LAPB device for the ethernet device
66 */
67static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
68{
69 struct lapbethdev *lapbeth;
70
71 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node) {
72 if (lapbeth->ethdev == dev)
73 return lapbeth;
74 }
75 return NULL;
76}
77
78static __inline__ int dev_is_ethdev(struct net_device *dev)
79{
80 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
81}
82
83/* ------------------------------------------------------------------------ */
84
85/*
86 * Receive a LAPB frame via an ethernet interface.
87 */
88static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
89{
90 int len, err;
91 struct lapbethdev *lapbeth;
92
93 if (dev_net(dev) != &init_net)
94 goto drop;
95
96 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
97 return NET_RX_DROP;
98
99 if (!pskb_may_pull(skb, 2))
100 goto drop;
101
102 rcu_read_lock();
103 lapbeth = lapbeth_get_x25_dev(dev);
104 if (!lapbeth)
105 goto drop_unlock;
106 if (!netif_running(lapbeth->axdev))
107 goto drop_unlock;
108
109 len = skb->data[0] + skb->data[1] * 256;
110 dev->stats.rx_packets++;
111 dev->stats.rx_bytes += len;
112
113 skb_pull(skb, 2); /* Remove the length bytes */
114 skb_trim(skb, len); /* Set the length of the data */
115
116 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
117 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
118 goto drop_unlock;
119 }
120out:
121 rcu_read_unlock();
122 return 0;
123drop_unlock:
124 kfree_skb(skb);
125 goto out;
126drop:
127 kfree_skb(skb);
128 return 0;
129}
130
131static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
132{
133 unsigned char *ptr;
134
135 skb_push(skb, 1);
136
137 if (skb_cow(skb, 1))
138 return NET_RX_DROP;
139
140 ptr = skb->data;
141 *ptr = 0x00;
142
143 skb->protocol = x25_type_trans(skb, dev);
144 return netif_rx(skb);
145}
146
147/*
148 * Send a LAPB frame via an ethernet interface
149 */
150static 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;
188out:
189 return err;
190drop_ok:
191 err = 0;
192drop:
193 kfree_skb(skb);
194 goto out;
195}
196
197static 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 ndev->stats.tx_packets++;
212 ndev->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
221static 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 netif_rx(skb);
236}
237
238static void lapbeth_disconnected(struct net_device *dev, int reason)
239{
240 unsigned char *ptr;
241 struct sk_buff *skb = dev_alloc_skb(1);
242
243 if (!skb) {
244 printk(KERN_ERR "lapbeth: out of memory\n");
245 return;
246 }
247
248 ptr = skb_put(skb, 1);
249 *ptr = 0x02;
250
251 skb->protocol = x25_type_trans(skb, dev);
252 netif_rx(skb);
253}
254
255/*
256 * Set AX.25 callsign
257 */
258static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
259{
260 struct sockaddr *sa = addr;
261 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
262 return 0;
263}
264
265
266static struct lapb_register_struct lapbeth_callbacks = {
267 .connect_confirmation = lapbeth_connected,
268 .connect_indication = lapbeth_connected,
269 .disconnect_confirmation = lapbeth_disconnected,
270 .disconnect_indication = lapbeth_disconnected,
271 .data_indication = lapbeth_data_indication,
272 .data_transmit = lapbeth_data_transmit,
273
274};
275
276/*
277 * open/close a device
278 */
279static int lapbeth_open(struct net_device *dev)
280{
281 int err;
282
283 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
284 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
285 return -ENODEV;
286 }
287
288 netif_start_queue(dev);
289 return 0;
290}
291
292static int lapbeth_close(struct net_device *dev)
293{
294 int err;
295
296 netif_stop_queue(dev);
297
298 if ((err = lapb_unregister(dev)) != LAPB_OK)
299 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
300
301 return 0;
302}
303
304/* ------------------------------------------------------------------------ */
305
306static const struct net_device_ops lapbeth_netdev_ops = {
307 .ndo_open = lapbeth_open,
308 .ndo_stop = lapbeth_close,
309 .ndo_start_xmit = lapbeth_xmit,
310 .ndo_set_mac_address = lapbeth_set_mac_address,
311};
312
313static void lapbeth_setup(struct net_device *dev)
314{
315 dev->netdev_ops = &lapbeth_netdev_ops;
316 dev->destructor = free_netdev;
317 dev->type = ARPHRD_X25;
318 dev->hard_header_len = 3;
319 dev->mtu = 1000;
320 dev->addr_len = 0;
321}
322
323/*
324 * Setup a new device.
325 */
326static int lapbeth_new_device(struct net_device *dev)
327{
328 struct net_device *ndev;
329 struct lapbethdev *lapbeth;
330 int rc = -ENOMEM;
331
332 ASSERT_RTNL();
333
334 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
335 lapbeth_setup);
336 if (!ndev)
337 goto out;
338
339 lapbeth = netdev_priv(ndev);
340 lapbeth->axdev = ndev;
341
342 dev_hold(dev);
343 lapbeth->ethdev = dev;
344
345 rc = dev_alloc_name(ndev, ndev->name);
346 if (rc < 0)
347 goto fail;
348
349 rc = -EIO;
350 if (register_netdevice(ndev))
351 goto fail;
352
353 list_add_rcu(&lapbeth->node, &lapbeth_devices);
354 rc = 0;
355out:
356 return rc;
357fail:
358 dev_put(dev);
359 free_netdev(ndev);
360 kfree(lapbeth);
361 goto out;
362}
363
364/*
365 * Free a lapb network device.
366 */
367static void lapbeth_free_device(struct lapbethdev *lapbeth)
368{
369 dev_put(lapbeth->ethdev);
370 list_del_rcu(&lapbeth->node);
371 unregister_netdevice(lapbeth->axdev);
372}
373
374/*
375 * Handle device status changes.
376 *
377 * Called from notifier with RTNL held.
378 */
379static int lapbeth_device_event(struct notifier_block *this,
380 unsigned long event, void *ptr)
381{
382 struct lapbethdev *lapbeth;
383 struct net_device *dev = ptr;
384
385 if (dev_net(dev) != &init_net)
386 return NOTIFY_DONE;
387
388 if (!dev_is_ethdev(dev))
389 return NOTIFY_DONE;
390
391 switch (event) {
392 case NETDEV_UP:
393 /* New ethernet device -> new LAPB interface */
394 if (lapbeth_get_x25_dev(dev) == NULL)
395 lapbeth_new_device(dev);
396 break;
397 case NETDEV_DOWN:
398 /* ethernet device closed -> close LAPB interface */
399 lapbeth = lapbeth_get_x25_dev(dev);
400 if (lapbeth)
401 dev_close(lapbeth->axdev);
402 break;
403 case NETDEV_UNREGISTER:
404 /* ethernet device disappears -> remove LAPB interface */
405 lapbeth = lapbeth_get_x25_dev(dev);
406 if (lapbeth)
407 lapbeth_free_device(lapbeth);
408 break;
409 }
410
411 return NOTIFY_DONE;
412}
413
414/* ------------------------------------------------------------------------ */
415
416static struct packet_type lapbeth_packet_type __read_mostly = {
417 .type = cpu_to_be16(ETH_P_DEC),
418 .func = lapbeth_rcv,
419};
420
421static struct notifier_block lapbeth_dev_notifier = {
422 .notifier_call = lapbeth_device_event,
423};
424
425static const char banner[] __initconst =
426 KERN_INFO "LAPB Ethernet driver version 0.02\n";
427
428static int __init lapbeth_init_driver(void)
429{
430 dev_add_pack(&lapbeth_packet_type);
431
432 register_netdevice_notifier(&lapbeth_dev_notifier);
433
434 printk(banner);
435
436 return 0;
437}
438module_init(lapbeth_init_driver);
439
440static void __exit lapbeth_cleanup_driver(void)
441{
442 struct lapbethdev *lapbeth;
443 struct list_head *entry, *tmp;
444
445 dev_remove_pack(&lapbeth_packet_type);
446 unregister_netdevice_notifier(&lapbeth_dev_notifier);
447
448 rtnl_lock();
449 list_for_each_safe(entry, tmp, &lapbeth_devices) {
450 lapbeth = list_entry(entry, struct lapbethdev, node);
451
452 dev_put(lapbeth->ethdev);
453 unregister_netdevice(lapbeth->axdev);
454 }
455 rtnl_unlock();
456}
457module_exit(lapbeth_cleanup_driver);
458
459MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
460MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
461MODULE_LICENSE("GPL");