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18#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
19
20#include <linux/errno.h>
21#include <linux/types.h>
22#include <linux/socket.h>
23#include <linux/in.h>
24#include <linux/slab.h>
25#include <linux/kernel.h>
26#include <linux/string.h>
27#include <linux/net.h>
28#include <linux/inet.h>
29#include <linux/netdevice.h>
30#include <linux/if_arp.h>
31#include <linux/skbuff.h>
32#include <net/sock.h>
33#include <linux/uaccess.h>
34#include <linux/mm.h>
35#include <linux/interrupt.h>
36#include <linux/notifier.h>
37#include <linux/stat.h>
38#include <linux/module.h>
39#include <linux/lapb.h>
40#include <linux/init.h>
41
42#include <net/x25device.h>
43
44static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
45
46
47
48
49#define MAXLAPBDEV 100
50
51struct lapbethdev {
52 struct list_head node;
53 struct net_device *ethdev;
54 struct net_device *axdev;
55 bool up;
56 spinlock_t up_lock;
57 struct sk_buff_head rx_queue;
58 struct napi_struct napi;
59};
60
61static LIST_HEAD(lapbeth_devices);
62
63static void lapbeth_connected(struct net_device *dev, int reason);
64static void lapbeth_disconnected(struct net_device *dev, int reason);
65
66
67
68
69
70static struct lapbethdev *lapbeth_get_x25_dev(struct net_device *dev)
71{
72 struct lapbethdev *lapbeth;
73
74 list_for_each_entry_rcu(lapbeth, &lapbeth_devices, node, lockdep_rtnl_is_held()) {
75 if (lapbeth->ethdev == dev)
76 return lapbeth;
77 }
78 return NULL;
79}
80
81static __inline__ int dev_is_ethdev(struct net_device *dev)
82{
83 return dev->type == ARPHRD_ETHER && strncmp(dev->name, "dummy", 5);
84}
85
86
87
88static int lapbeth_napi_poll(struct napi_struct *napi, int budget)
89{
90 struct lapbethdev *lapbeth = container_of(napi, struct lapbethdev,
91 napi);
92 struct sk_buff *skb;
93 int processed = 0;
94
95 for (; processed < budget; ++processed) {
96 skb = skb_dequeue(&lapbeth->rx_queue);
97 if (!skb)
98 break;
99 netif_receive_skb_core(skb);
100 }
101
102 if (processed < budget)
103 napi_complete(napi);
104
105 return processed;
106}
107
108
109
110static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev,
111 struct packet_type *ptype, struct net_device *orig_dev)
112{
113 int len, err;
114 struct lapbethdev *lapbeth;
115
116 if (dev_net(dev) != &init_net)
117 goto drop;
118
119 skb = skb_share_check(skb, GFP_ATOMIC);
120 if (!skb)
121 return NET_RX_DROP;
122
123 if (!pskb_may_pull(skb, 2))
124 goto drop;
125
126 rcu_read_lock();
127 lapbeth = lapbeth_get_x25_dev(dev);
128 if (!lapbeth)
129 goto drop_unlock_rcu;
130 spin_lock_bh(&lapbeth->up_lock);
131 if (!lapbeth->up)
132 goto drop_unlock;
133
134 len = skb->data[0] + skb->data[1] * 256;
135 dev->stats.rx_packets++;
136 dev->stats.rx_bytes += len;
137
138 skb_pull(skb, 2);
139 skb_trim(skb, len);
140
141 err = lapb_data_received(lapbeth->axdev, skb);
142 if (err != LAPB_OK) {
143 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
144 goto drop_unlock;
145 }
146out:
147 spin_unlock_bh(&lapbeth->up_lock);
148 rcu_read_unlock();
149 return 0;
150drop_unlock:
151 kfree_skb(skb);
152 goto out;
153drop_unlock_rcu:
154 rcu_read_unlock();
155drop:
156 kfree_skb(skb);
157 return 0;
158}
159
160static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
161{
162 struct lapbethdev *lapbeth = netdev_priv(dev);
163 unsigned char *ptr;
164
165 if (skb_cow(skb, 1)) {
166 kfree_skb(skb);
167 return NET_RX_DROP;
168 }
169
170 skb_push(skb, 1);
171
172 ptr = skb->data;
173 *ptr = X25_IFACE_DATA;
174
175 skb->protocol = x25_type_trans(skb, dev);
176
177 skb_queue_tail(&lapbeth->rx_queue, skb);
178 napi_schedule(&lapbeth->napi);
179 return NET_RX_SUCCESS;
180}
181
182
183
184static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
185 struct net_device *dev)
186{
187 struct lapbethdev *lapbeth = netdev_priv(dev);
188 int err;
189
190 spin_lock_bh(&lapbeth->up_lock);
191 if (!lapbeth->up)
192 goto drop;
193
194
195
196
197 if (skb->len < 1)
198 goto drop;
199
200 switch (skb->data[0]) {
201 case X25_IFACE_DATA:
202 break;
203 case X25_IFACE_CONNECT:
204 err = lapb_connect_request(dev);
205 if (err == LAPB_CONNECTED)
206 lapbeth_connected(dev, LAPB_OK);
207 else if (err != LAPB_OK)
208 pr_err("lapb_connect_request error: %d\n", err);
209 goto drop;
210 case X25_IFACE_DISCONNECT:
211 err = lapb_disconnect_request(dev);
212 if (err == LAPB_NOTCONNECTED)
213 lapbeth_disconnected(dev, LAPB_OK);
214 else if (err != LAPB_OK)
215 pr_err("lapb_disconnect_request err: %d\n", err);
216 fallthrough;
217 default:
218 goto drop;
219 }
220
221 skb_pull(skb, 1);
222
223 err = lapb_data_request(dev, skb);
224 if (err != LAPB_OK) {
225 pr_err("lapb_data_request error - %d\n", err);
226 goto drop;
227 }
228out:
229 spin_unlock_bh(&lapbeth->up_lock);
230 return NETDEV_TX_OK;
231drop:
232 kfree_skb(skb);
233 goto out;
234}
235
236static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
237{
238 struct lapbethdev *lapbeth = netdev_priv(ndev);
239 unsigned char *ptr;
240 struct net_device *dev;
241 int size = skb->len;
242
243 ptr = skb_push(skb, 2);
244
245 *ptr++ = size % 256;
246 *ptr++ = size / 256;
247
248 ndev->stats.tx_packets++;
249 ndev->stats.tx_bytes += size;
250
251 skb->dev = dev = lapbeth->ethdev;
252
253 skb->protocol = htons(ETH_P_DEC);
254
255 skb_reset_network_header(skb);
256
257 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
258
259 dev_queue_xmit(skb);
260}
261
262static void lapbeth_connected(struct net_device *dev, int reason)
263{
264 struct lapbethdev *lapbeth = netdev_priv(dev);
265 unsigned char *ptr;
266 struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC);
267
268 if (!skb)
269 return;
270
271 ptr = skb_put(skb, 1);
272 *ptr = X25_IFACE_CONNECT;
273
274 skb->protocol = x25_type_trans(skb, dev);
275
276 skb_queue_tail(&lapbeth->rx_queue, skb);
277 napi_schedule(&lapbeth->napi);
278}
279
280static void lapbeth_disconnected(struct net_device *dev, int reason)
281{
282 struct lapbethdev *lapbeth = netdev_priv(dev);
283 unsigned char *ptr;
284 struct sk_buff *skb = __dev_alloc_skb(1, GFP_ATOMIC | __GFP_NOMEMALLOC);
285
286 if (!skb)
287 return;
288
289 ptr = skb_put(skb, 1);
290 *ptr = X25_IFACE_DISCONNECT;
291
292 skb->protocol = x25_type_trans(skb, dev);
293
294 skb_queue_tail(&lapbeth->rx_queue, skb);
295 napi_schedule(&lapbeth->napi);
296}
297
298
299
300static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
301{
302 struct sockaddr *sa = addr;
303
304 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
305 return 0;
306}
307
308static const struct lapb_register_struct lapbeth_callbacks = {
309 .connect_confirmation = lapbeth_connected,
310 .connect_indication = lapbeth_connected,
311 .disconnect_confirmation = lapbeth_disconnected,
312 .disconnect_indication = lapbeth_disconnected,
313 .data_indication = lapbeth_data_indication,
314 .data_transmit = lapbeth_data_transmit,
315};
316
317
318
319static int lapbeth_open(struct net_device *dev)
320{
321 struct lapbethdev *lapbeth = netdev_priv(dev);
322 int err;
323
324 napi_enable(&lapbeth->napi);
325
326 err = lapb_register(dev, &lapbeth_callbacks);
327 if (err != LAPB_OK) {
328 pr_err("lapb_register error: %d\n", err);
329 return -ENODEV;
330 }
331
332 spin_lock_bh(&lapbeth->up_lock);
333 lapbeth->up = true;
334 spin_unlock_bh(&lapbeth->up_lock);
335
336 return 0;
337}
338
339static int lapbeth_close(struct net_device *dev)
340{
341 struct lapbethdev *lapbeth = netdev_priv(dev);
342 int err;
343
344 spin_lock_bh(&lapbeth->up_lock);
345 lapbeth->up = false;
346 spin_unlock_bh(&lapbeth->up_lock);
347
348 err = lapb_unregister(dev);
349 if (err != LAPB_OK)
350 pr_err("lapb_unregister error: %d\n", err);
351
352 napi_disable(&lapbeth->napi);
353
354 return 0;
355}
356
357
358
359static const struct net_device_ops lapbeth_netdev_ops = {
360 .ndo_open = lapbeth_open,
361 .ndo_stop = lapbeth_close,
362 .ndo_start_xmit = lapbeth_xmit,
363 .ndo_set_mac_address = lapbeth_set_mac_address,
364};
365
366static void lapbeth_setup(struct net_device *dev)
367{
368 dev->netdev_ops = &lapbeth_netdev_ops;
369 dev->needs_free_netdev = true;
370 dev->type = ARPHRD_X25;
371 dev->hard_header_len = 0;
372 dev->mtu = 1000;
373 dev->addr_len = 0;
374}
375
376
377
378static int lapbeth_new_device(struct net_device *dev)
379{
380 struct net_device *ndev;
381 struct lapbethdev *lapbeth;
382 int rc = -ENOMEM;
383
384 ASSERT_RTNL();
385
386 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", NET_NAME_UNKNOWN,
387 lapbeth_setup);
388 if (!ndev)
389 goto out;
390
391
392
393
394
395
396
397 ndev->needed_headroom = -1 + 3 + 2 + dev->hard_header_len
398 + dev->needed_headroom;
399 ndev->needed_tailroom = dev->needed_tailroom;
400
401 lapbeth = netdev_priv(ndev);
402 lapbeth->axdev = ndev;
403
404 dev_hold(dev);
405 lapbeth->ethdev = dev;
406
407 lapbeth->up = false;
408 spin_lock_init(&lapbeth->up_lock);
409
410 skb_queue_head_init(&lapbeth->rx_queue);
411 netif_napi_add(ndev, &lapbeth->napi, lapbeth_napi_poll, 16);
412
413 rc = -EIO;
414 if (register_netdevice(ndev))
415 goto fail;
416
417 list_add_rcu(&lapbeth->node, &lapbeth_devices);
418 rc = 0;
419out:
420 return rc;
421fail:
422 dev_put(dev);
423 free_netdev(ndev);
424 goto out;
425}
426
427
428
429static void lapbeth_free_device(struct lapbethdev *lapbeth)
430{
431 dev_put(lapbeth->ethdev);
432 list_del_rcu(&lapbeth->node);
433 unregister_netdevice(lapbeth->axdev);
434}
435
436
437
438
439
440static int lapbeth_device_event(struct notifier_block *this,
441 unsigned long event, void *ptr)
442{
443 struct lapbethdev *lapbeth;
444 struct net_device *dev = netdev_notifier_info_to_dev(ptr);
445
446 if (dev_net(dev) != &init_net)
447 return NOTIFY_DONE;
448
449 if (!dev_is_ethdev(dev))
450 return NOTIFY_DONE;
451
452 switch (event) {
453 case NETDEV_UP:
454
455 if (!lapbeth_get_x25_dev(dev))
456 lapbeth_new_device(dev);
457 break;
458 case NETDEV_GOING_DOWN:
459
460 lapbeth = lapbeth_get_x25_dev(dev);
461 if (lapbeth)
462 dev_close(lapbeth->axdev);
463 break;
464 case NETDEV_UNREGISTER:
465
466 lapbeth = lapbeth_get_x25_dev(dev);
467 if (lapbeth)
468 lapbeth_free_device(lapbeth);
469 break;
470 }
471
472 return NOTIFY_DONE;
473}
474
475
476
477static struct packet_type lapbeth_packet_type __read_mostly = {
478 .type = cpu_to_be16(ETH_P_DEC),
479 .func = lapbeth_rcv,
480};
481
482static struct notifier_block lapbeth_dev_notifier = {
483 .notifier_call = lapbeth_device_event,
484};
485
486static const char banner[] __initconst =
487 KERN_INFO "LAPB Ethernet driver version 0.02\n";
488
489static int __init lapbeth_init_driver(void)
490{
491 dev_add_pack(&lapbeth_packet_type);
492
493 register_netdevice_notifier(&lapbeth_dev_notifier);
494
495 printk(banner);
496
497 return 0;
498}
499module_init(lapbeth_init_driver);
500
501static void __exit lapbeth_cleanup_driver(void)
502{
503 struct lapbethdev *lapbeth;
504 struct list_head *entry, *tmp;
505
506 dev_remove_pack(&lapbeth_packet_type);
507 unregister_netdevice_notifier(&lapbeth_dev_notifier);
508
509 rtnl_lock();
510 list_for_each_safe(entry, tmp, &lapbeth_devices) {
511 lapbeth = list_entry(entry, struct lapbethdev, node);
512
513 dev_put(lapbeth->ethdev);
514 unregister_netdevice(lapbeth->axdev);
515 }
516 rtnl_unlock();
517}
518module_exit(lapbeth_cleanup_driver);
519
520MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
521MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
522MODULE_LICENSE("GPL");
523
