Merge branch 'upstream-fixes' into upstream
[linux-2.6] / 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 ((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");