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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/slab.h>
28#include <linux/kernel.h>
29#include <linux/string.h>
30#include <linux/net.h>
31#include <linux/inet.h>
32#include <linux/netdevice.h>
33#include <linux/if_arp.h>
34#include <linux/skbuff.h>
35#include <net/sock.h>
36#include <asm/system.h>
37#include <asm/uaccess.h>
38#include <linux/mm.h>
39#include <linux/interrupt.h>
40#include <linux/notifier.h>
41#include <linux/stat.h>
42#include <linux/netfilter.h>
43#include <linux/module.h>
44#include <linux/lapb.h>
45#include <linux/init.h>
46
47#include <net/x25device.h>
48
49static char bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
50
51/* If this number is made larger, check that the temporary string buffer
52 * in lapbeth_new_device is large enough to store the probe device name.*/
53#define MAXLAPBDEV 100
54
55struct lapbethdev {
56 struct list_head node;
57 struct net_device *ethdev; /* link to ethernet device */
58 struct net_device *axdev; /* lapbeth device (lapb#) */
59};
60
61static LIST_HEAD(lapbeth_devices);
62
63/* ------------------------------------------------------------------------ */
64
65/*
66 * Get the LAPB device for the ethernet device
67 */
68static 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
79static __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 */
89static 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 len = skb->data[0] + skb->data[1] * 256;
111 dev->stats.rx_packets++;
112 dev->stats.rx_bytes += len;
113
114 skb_pull(skb, 2); /* Remove the length bytes */
115 skb_trim(skb, len); /* Set the length of the data */
116
117 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
118 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
119 goto drop_unlock;
120 }
121out:
122 rcu_read_unlock();
123 return 0;
124drop_unlock:
125 kfree_skb(skb);
126 goto out;
127drop:
128 kfree_skb(skb);
129 return 0;
130}
131
132static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
133{
134 unsigned char *ptr;
135
136 skb_push(skb, 1);
137
138 if (skb_cow(skb, 1))
139 return NET_RX_DROP;
140
141 ptr = skb->data;
142 *ptr = X25_IFACE_DATA;
143
144 skb->protocol = x25_type_trans(skb, dev);
145 return netif_rx(skb);
146}
147
148/*
149 * Send a LAPB frame via an ethernet interface
150 */
151static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
152 struct net_device *dev)
153{
154 int err;
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 switch (skb->data[0]) {
164 case X25_IFACE_DATA:
165 break;
166 case X25_IFACE_CONNECT:
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;
171 case X25_IFACE_DISCONNECT:
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;
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 goto drop;
185 }
186out:
187 return NETDEV_TX_OK;
188drop:
189 kfree_skb(skb);
190 goto out;
191}
192
193static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
194{
195 struct lapbethdev *lapbeth = netdev_priv(ndev);
196 unsigned char *ptr;
197 struct net_device *dev;
198 int size = skb->len;
199
200 skb->protocol = htons(ETH_P_X25);
201
202 ptr = skb_push(skb, 2);
203
204 *ptr++ = size % 256;
205 *ptr++ = size / 256;
206
207 ndev->stats.tx_packets++;
208 ndev->stats.tx_bytes += size;
209
210 skb->dev = dev = lapbeth->ethdev;
211
212 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
213
214 dev_queue_xmit(skb);
215}
216
217static void lapbeth_connected(struct net_device *dev, int reason)
218{
219 unsigned char *ptr;
220 struct sk_buff *skb = dev_alloc_skb(1);
221
222 if (!skb) {
223 printk(KERN_ERR "lapbeth: out of memory\n");
224 return;
225 }
226
227 ptr = skb_put(skb, 1);
228 *ptr = X25_IFACE_CONNECT;
229
230 skb->protocol = x25_type_trans(skb, dev);
231 netif_rx(skb);
232}
233
234static void lapbeth_disconnected(struct net_device *dev, int reason)
235{
236 unsigned char *ptr;
237 struct sk_buff *skb = dev_alloc_skb(1);
238
239 if (!skb) {
240 printk(KERN_ERR "lapbeth: out of memory\n");
241 return;
242 }
243
244 ptr = skb_put(skb, 1);
245 *ptr = X25_IFACE_DISCONNECT;
246
247 skb->protocol = x25_type_trans(skb, dev);
248 netif_rx(skb);
249}
250
251/*
252 * Set AX.25 callsign
253 */
254static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
255{
256 struct sockaddr *sa = addr;
257 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
258 return 0;
259}
260
261
262static struct lapb_register_struct lapbeth_callbacks = {
263 .connect_confirmation = lapbeth_connected,
264 .connect_indication = lapbeth_connected,
265 .disconnect_confirmation = lapbeth_disconnected,
266 .disconnect_indication = lapbeth_disconnected,
267 .data_indication = lapbeth_data_indication,
268 .data_transmit = lapbeth_data_transmit,
269
270};
271
272/*
273 * open/close a device
274 */
275static int lapbeth_open(struct net_device *dev)
276{
277 int err;
278
279 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
280 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
281 return -ENODEV;
282 }
283
284 netif_start_queue(dev);
285 return 0;
286}
287
288static int lapbeth_close(struct net_device *dev)
289{
290 int err;
291
292 netif_stop_queue(dev);
293
294 if ((err = lapb_unregister(dev)) != LAPB_OK)
295 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
296
297 return 0;
298}
299
300/* ------------------------------------------------------------------------ */
301
302static const struct net_device_ops lapbeth_netdev_ops = {
303 .ndo_open = lapbeth_open,
304 .ndo_stop = lapbeth_close,
305 .ndo_start_xmit = lapbeth_xmit,
306 .ndo_set_mac_address = lapbeth_set_mac_address,
307};
308
309static void lapbeth_setup(struct net_device *dev)
310{
311 dev->netdev_ops = &lapbeth_netdev_ops;
312 dev->destructor = free_netdev;
313 dev->type = ARPHRD_X25;
314 dev->hard_header_len = 3;
315 dev->mtu = 1000;
316 dev->addr_len = 0;
317}
318
319/*
320 * Setup a new device.
321 */
322static int lapbeth_new_device(struct net_device *dev)
323{
324 struct net_device *ndev;
325 struct lapbethdev *lapbeth;
326 int rc = -ENOMEM;
327
328 ASSERT_RTNL();
329
330 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
331 lapbeth_setup);
332 if (!ndev)
333 goto out;
334
335 lapbeth = netdev_priv(ndev);
336 lapbeth->axdev = ndev;
337
338 dev_hold(dev);
339 lapbeth->ethdev = dev;
340
341 rc = dev_alloc_name(ndev, ndev->name);
342 if (rc < 0)
343 goto fail;
344
345 rc = -EIO;
346 if (register_netdevice(ndev))
347 goto fail;
348
349 list_add_rcu(&lapbeth->node, &lapbeth_devices);
350 rc = 0;
351out:
352 return rc;
353fail:
354 dev_put(dev);
355 free_netdev(ndev);
356 kfree(lapbeth);
357 goto out;
358}
359
360/*
361 * Free a lapb network device.
362 */
363static void lapbeth_free_device(struct lapbethdev *lapbeth)
364{
365 dev_put(lapbeth->ethdev);
366 list_del_rcu(&lapbeth->node);
367 unregister_netdevice(lapbeth->axdev);
368}
369
370/*
371 * Handle device status changes.
372 *
373 * Called from notifier with RTNL held.
374 */
375static int lapbeth_device_event(struct notifier_block *this,
376 unsigned long event, void *ptr)
377{
378 struct lapbethdev *lapbeth;
379 struct net_device *dev = ptr;
380
381 if (dev_net(dev) != &init_net)
382 return NOTIFY_DONE;
383
384 if (!dev_is_ethdev(dev))
385 return NOTIFY_DONE;
386
387 switch (event) {
388 case NETDEV_UP:
389 /* New ethernet device -> new LAPB interface */
390 if (lapbeth_get_x25_dev(dev) == NULL)
391 lapbeth_new_device(dev);
392 break;
393 case NETDEV_DOWN:
394 /* ethernet device closed -> close LAPB interface */
395 lapbeth = lapbeth_get_x25_dev(dev);
396 if (lapbeth)
397 dev_close(lapbeth->axdev);
398 break;
399 case NETDEV_UNREGISTER:
400 /* ethernet device disappears -> remove LAPB interface */
401 lapbeth = lapbeth_get_x25_dev(dev);
402 if (lapbeth)
403 lapbeth_free_device(lapbeth);
404 break;
405 }
406
407 return NOTIFY_DONE;
408}
409
410/* ------------------------------------------------------------------------ */
411
412static struct packet_type lapbeth_packet_type __read_mostly = {
413 .type = cpu_to_be16(ETH_P_DEC),
414 .func = lapbeth_rcv,
415};
416
417static struct notifier_block lapbeth_dev_notifier = {
418 .notifier_call = lapbeth_device_event,
419};
420
421static const char banner[] __initconst =
422 KERN_INFO "LAPB Ethernet driver version 0.02\n";
423
424static int __init lapbeth_init_driver(void)
425{
426 dev_add_pack(&lapbeth_packet_type);
427
428 register_netdevice_notifier(&lapbeth_dev_notifier);
429
430 printk(banner);
431
432 return 0;
433}
434module_init(lapbeth_init_driver);
435
436static void __exit lapbeth_cleanup_driver(void)
437{
438 struct lapbethdev *lapbeth;
439 struct list_head *entry, *tmp;
440
441 dev_remove_pack(&lapbeth_packet_type);
442 unregister_netdevice_notifier(&lapbeth_dev_notifier);
443
444 rtnl_lock();
445 list_for_each_safe(entry, tmp, &lapbeth_devices) {
446 lapbeth = list_entry(entry, struct lapbethdev, node);
447
448 dev_put(lapbeth->ethdev);
449 unregister_netdevice(lapbeth->axdev);
450 }
451 rtnl_unlock();
452}
453module_exit(lapbeth_cleanup_driver);
454
455MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
456MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
457MODULE_LICENSE("GPL");