fb37b809523150d2424710d7cdfdb5c1bff206e7
[linux-3.10.git] / drivers / net / wan / lapbether.c
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, struct net_device *orig_dev)
90 {
91         int len, err;
92         struct lapbethdev *lapbeth;
93
94         if (dev->nd_net != &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
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         skb->dev->last_rx = jiffies;
147         return netif_rx(skb);
148 }
149
150 /*
151  *      Send a LAPB frame via an ethernet interface
152  */
153 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
154 {
155         int err = -ENODEV;
156
157         /*
158          * Just to be *really* sure not to send anything if the interface
159          * is down, the ethernet device may have gone.
160          */
161         if (!netif_running(dev)) {
162                 goto drop;
163         }
164
165         switch (skb->data[0]) {
166         case 0x00:
167                 err = 0;
168                 break;
169         case 0x01:
170                 if ((err = lapb_connect_request(dev)) != LAPB_OK)
171                         printk(KERN_ERR "lapbeth: lapb_connect_request "
172                                "error: %d\n", err);
173                 goto drop_ok;
174         case 0x02:
175                 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
176                         printk(KERN_ERR "lapbeth: lapb_disconnect_request "
177                                "err: %d\n", err);
178                 /* Fall thru */
179         default:
180                 goto drop_ok;
181         }
182
183         skb_pull(skb, 1);
184
185         if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
186                 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
187                 err = -ENOMEM;
188                 goto drop;
189         }
190         err = 0;
191 out:
192         return err;
193 drop_ok:
194         err = 0;
195 drop:
196         kfree_skb(skb);
197         goto out;
198 }
199
200 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
201 {
202         struct lapbethdev *lapbeth = netdev_priv(ndev);
203         unsigned char *ptr;
204         struct net_device *dev;
205         int size = skb->len;
206
207         skb->protocol = htons(ETH_P_X25);
208
209         ptr = skb_push(skb, 2);
210
211         *ptr++ = size % 256;
212         *ptr++ = size / 256;
213
214         lapbeth->stats.tx_packets++;
215         lapbeth->stats.tx_bytes += size;
216
217         skb->dev = dev = lapbeth->ethdev;
218
219         dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
220
221         dev_queue_xmit(skb);
222 }
223
224 static void lapbeth_connected(struct net_device *dev, int reason)
225 {
226         unsigned char *ptr;
227         struct sk_buff *skb = dev_alloc_skb(1);
228
229         if (!skb) {
230                 printk(KERN_ERR "lapbeth: out of memory\n");
231                 return;
232         }
233
234         ptr  = skb_put(skb, 1);
235         *ptr = 0x01;
236
237         skb->protocol = x25_type_trans(skb, dev);
238         skb->dev->last_rx = jiffies;
239         netif_rx(skb);
240 }
241
242 static void lapbeth_disconnected(struct net_device *dev, int reason)
243 {
244         unsigned char *ptr;
245         struct sk_buff *skb = dev_alloc_skb(1);
246
247         if (!skb) {
248                 printk(KERN_ERR "lapbeth: out of memory\n");
249                 return;
250         }
251
252         ptr  = skb_put(skb, 1);
253         *ptr = 0x02;
254
255         skb->protocol = x25_type_trans(skb, dev);
256         skb->dev->last_rx = jiffies;
257         netif_rx(skb);
258 }
259
260 /*
261  *      Statistics
262  */
263 static struct net_device_stats *lapbeth_get_stats(struct net_device *dev)
264 {
265         struct lapbethdev *lapbeth = netdev_priv(dev);
266         return &lapbeth->stats;
267 }
268
269 /*
270  *      Set AX.25 callsign
271  */
272 static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
273 {
274         struct sockaddr *sa = addr;
275         memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
276         return 0;
277 }
278
279
280 static struct lapb_register_struct lapbeth_callbacks = {
281         .connect_confirmation    = lapbeth_connected,
282         .connect_indication      = lapbeth_connected,
283         .disconnect_confirmation = lapbeth_disconnected,
284         .disconnect_indication   = lapbeth_disconnected,
285         .data_indication         = lapbeth_data_indication,
286         .data_transmit           = lapbeth_data_transmit,
287
288 };
289
290 /*
291  * open/close a device
292  */
293 static int lapbeth_open(struct net_device *dev)
294 {
295         int err;
296
297         if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
298                 printk(KERN_ERR "lapbeth: lapb_register error - %d\n", err);
299                 return -ENODEV;
300         }
301
302         netif_start_queue(dev);
303         return 0;
304 }
305
306 static int lapbeth_close(struct net_device *dev)
307 {
308         int err;
309
310         netif_stop_queue(dev);
311
312         if ((err = lapb_unregister(dev)) != LAPB_OK)
313                 printk(KERN_ERR "lapbeth: lapb_unregister error - %d\n", err);
314
315         return 0;
316 }
317
318 /* ------------------------------------------------------------------------ */
319
320 static void lapbeth_setup(struct net_device *dev)
321 {
322         dev->hard_start_xmit = lapbeth_xmit;
323         dev->open            = lapbeth_open;
324         dev->stop            = lapbeth_close;
325         dev->destructor      = free_netdev;
326         dev->set_mac_address = lapbeth_set_mac_address;
327         dev->get_stats       = lapbeth_get_stats;
328         dev->type            = ARPHRD_X25;
329         dev->hard_header_len = 3;
330         dev->mtu             = 1000;
331         dev->addr_len        = 0;
332 }
333
334 /*
335  *      Setup a new device.
336  */
337 static int lapbeth_new_device(struct net_device *dev)
338 {
339         struct net_device *ndev;
340         struct lapbethdev *lapbeth;
341         int rc = -ENOMEM;
342
343         ASSERT_RTNL();
344
345         ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 
346                            lapbeth_setup);
347         if (!ndev)
348                 goto out;
349
350         lapbeth = netdev_priv(ndev);
351         lapbeth->axdev = ndev;
352
353         dev_hold(dev);
354         lapbeth->ethdev = dev;
355
356         rc = dev_alloc_name(ndev, ndev->name);
357         if (rc < 0) 
358                 goto fail;
359
360         rc = -EIO;
361         if (register_netdevice(ndev))
362                 goto fail;
363
364         list_add_rcu(&lapbeth->node, &lapbeth_devices);
365         rc = 0;
366 out:
367         return rc;
368 fail:
369         dev_put(dev);
370         free_netdev(ndev);
371         kfree(lapbeth);
372         goto out;
373 }
374
375 /*
376  *      Free a lapb network device.
377  */
378 static void lapbeth_free_device(struct lapbethdev *lapbeth)
379 {
380         dev_put(lapbeth->ethdev);
381         list_del_rcu(&lapbeth->node);
382         unregister_netdevice(lapbeth->axdev);
383 }
384
385 /*
386  *      Handle device status changes.
387  *
388  * Called from notifier with RTNL held.
389  */
390 static int lapbeth_device_event(struct notifier_block *this,
391                                 unsigned long event, void *ptr)
392 {
393         struct lapbethdev *lapbeth;
394         struct net_device *dev = ptr;
395
396         if (dev->nd_net != &init_net)
397                 return NOTIFY_DONE;
398
399         if (!dev_is_ethdev(dev))
400                 return NOTIFY_DONE;
401
402         switch (event) {
403         case NETDEV_UP:
404                 /* New ethernet device -> new LAPB interface     */
405                 if (lapbeth_get_x25_dev(dev) == NULL)
406                         lapbeth_new_device(dev);
407                 break;
408         case NETDEV_DOWN:       
409                 /* ethernet device closed -> close LAPB interface */
410                 lapbeth = lapbeth_get_x25_dev(dev);
411                 if (lapbeth) 
412                         dev_close(lapbeth->axdev);
413                 break;
414         case NETDEV_UNREGISTER:
415                 /* ethernet device disappears -> remove LAPB interface */
416                 lapbeth = lapbeth_get_x25_dev(dev);
417                 if (lapbeth)
418                         lapbeth_free_device(lapbeth);
419                 break;
420         }
421
422         return NOTIFY_DONE;
423 }
424
425 /* ------------------------------------------------------------------------ */
426
427 static struct packet_type lapbeth_packet_type = {
428         .type = __constant_htons(ETH_P_DEC),
429         .func = lapbeth_rcv,
430 };
431
432 static struct notifier_block lapbeth_dev_notifier = {
433         .notifier_call = lapbeth_device_event,
434 };
435
436 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
437
438 static int __init lapbeth_init_driver(void)
439 {
440         dev_add_pack(&lapbeth_packet_type);
441
442         register_netdevice_notifier(&lapbeth_dev_notifier);
443
444         printk(banner);
445
446         return 0;
447 }
448 module_init(lapbeth_init_driver);
449
450 static void __exit lapbeth_cleanup_driver(void)
451 {
452         struct lapbethdev *lapbeth;
453         struct list_head *entry, *tmp;
454
455         dev_remove_pack(&lapbeth_packet_type);
456         unregister_netdevice_notifier(&lapbeth_dev_notifier);
457
458         rtnl_lock();
459         list_for_each_safe(entry, tmp, &lapbeth_devices) {
460                 lapbeth = list_entry(entry, struct lapbethdev, node);
461
462                 unregister_netdevice(lapbeth->axdev);
463         }
464         rtnl_unlock();
465 }
466 module_exit(lapbeth_cleanup_driver);
467
468 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
469 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
470 MODULE_LICENSE("GPL");