Merge branch 'master' of master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6
[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 LIST_HEAD(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_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         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         return netif_rx(skb);
147 }
148
149 /*
150  *      Send a LAPB frame via an ethernet interface
151  */
152 static int lapbeth_xmit(struct sk_buff *skb, struct net_device *dev)
153 {
154         int err = -ENODEV;
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
164         switch (skb->data[0]) {
165         case 0x00:
166                 err = 0;
167                 break;
168         case 0x01:
169                 if ((err = lapb_connect_request(dev)) != LAPB_OK)
170                         printk(KERN_ERR "lapbeth: lapb_connect_request "
171                                "error: %d\n", err);
172                 goto drop_ok;
173         case 0x02:
174                 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
175                         printk(KERN_ERR "lapbeth: lapb_disconnect_request "
176                                "err: %d\n", err);
177                 /* Fall thru */
178         default:
179                 goto drop_ok;
180         }
181
182         skb_pull(skb, 1);
183
184         if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
185                 printk(KERN_ERR "lapbeth: lapb_data_request error - %d\n", err);
186                 err = -ENOMEM;
187                 goto drop;
188         }
189         err = 0;
190 out:
191         return err;
192 drop_ok:
193         err = 0;
194 drop:
195         kfree_skb(skb);
196         goto out;
197 }
198
199 static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
200 {
201         struct lapbethdev *lapbeth = netdev_priv(ndev);
202         unsigned char *ptr;
203         struct net_device *dev;
204         int size = skb->len;
205
206         skb->protocol = htons(ETH_P_X25);
207
208         ptr = skb_push(skb, 2);
209
210         *ptr++ = size % 256;
211         *ptr++ = size / 256;
212
213         lapbeth->stats.tx_packets++;
214         lapbeth->stats.tx_bytes += size;
215
216         skb->dev = dev = lapbeth->ethdev;
217
218         dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
219
220         dev_queue_xmit(skb);
221 }
222
223 static void lapbeth_connected(struct net_device *dev, int reason)
224 {
225         unsigned char *ptr;
226         struct sk_buff *skb = dev_alloc_skb(1);
227
228         if (!skb) {
229                 printk(KERN_ERR "lapbeth: out of memory\n");
230                 return;
231         }
232
233         ptr  = skb_put(skb, 1);
234         *ptr = 0x01;
235
236         skb->protocol = x25_type_trans(skb, dev);
237         netif_rx(skb);
238 }
239
240 static void lapbeth_disconnected(struct net_device *dev, int reason)
241 {
242         unsigned char *ptr;
243         struct sk_buff *skb = dev_alloc_skb(1);
244
245         if (!skb) {
246                 printk(KERN_ERR "lapbeth: out of memory\n");
247                 return;
248         }
249
250         ptr  = skb_put(skb, 1);
251         *ptr = 0x02;
252
253         skb->protocol = x25_type_trans(skb, dev);
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 }
330
331 /*
332  *      Setup a new device.
333  */
334 static int lapbeth_new_device(struct net_device *dev)
335 {
336         struct net_device *ndev;
337         struct lapbethdev *lapbeth;
338         int rc = -ENOMEM;
339
340         ASSERT_RTNL();
341
342         ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d", 
343                            lapbeth_setup);
344         if (!ndev)
345                 goto out;
346
347         lapbeth = netdev_priv(ndev);
348         lapbeth->axdev = ndev;
349
350         dev_hold(dev);
351         lapbeth->ethdev = dev;
352
353         rc = dev_alloc_name(ndev, ndev->name);
354         if (rc < 0) 
355                 goto fail;
356
357         rc = -EIO;
358         if (register_netdevice(ndev))
359                 goto fail;
360
361         list_add_rcu(&lapbeth->node, &lapbeth_devices);
362         rc = 0;
363 out:
364         return rc;
365 fail:
366         dev_put(dev);
367         free_netdev(ndev);
368         kfree(lapbeth);
369         goto out;
370 }
371
372 /*
373  *      Free a lapb network device.
374  */
375 static void lapbeth_free_device(struct lapbethdev *lapbeth)
376 {
377         dev_put(lapbeth->ethdev);
378         list_del_rcu(&lapbeth->node);
379         unregister_netdevice(lapbeth->axdev);
380 }
381
382 /*
383  *      Handle device status changes.
384  *
385  * Called from notifier with RTNL held.
386  */
387 static int lapbeth_device_event(struct notifier_block *this,
388                                 unsigned long event, void *ptr)
389 {
390         struct lapbethdev *lapbeth;
391         struct net_device *dev = ptr;
392
393         if (dev_net(dev) != &init_net)
394                 return NOTIFY_DONE;
395
396         if (!dev_is_ethdev(dev))
397                 return NOTIFY_DONE;
398
399         switch (event) {
400         case NETDEV_UP:
401                 /* New ethernet device -> new LAPB interface     */
402                 if (lapbeth_get_x25_dev(dev) == NULL)
403                         lapbeth_new_device(dev);
404                 break;
405         case NETDEV_DOWN:       
406                 /* ethernet device closed -> close LAPB interface */
407                 lapbeth = lapbeth_get_x25_dev(dev);
408                 if (lapbeth) 
409                         dev_close(lapbeth->axdev);
410                 break;
411         case NETDEV_UNREGISTER:
412                 /* ethernet device disappears -> remove LAPB interface */
413                 lapbeth = lapbeth_get_x25_dev(dev);
414                 if (lapbeth)
415                         lapbeth_free_device(lapbeth);
416                 break;
417         }
418
419         return NOTIFY_DONE;
420 }
421
422 /* ------------------------------------------------------------------------ */
423
424 static struct packet_type lapbeth_packet_type = {
425         .type = __constant_htons(ETH_P_DEC),
426         .func = lapbeth_rcv,
427 };
428
429 static struct notifier_block lapbeth_dev_notifier = {
430         .notifier_call = lapbeth_device_event,
431 };
432
433 static char banner[] __initdata = KERN_INFO "LAPB Ethernet driver version 0.02\n";
434
435 static int __init lapbeth_init_driver(void)
436 {
437         dev_add_pack(&lapbeth_packet_type);
438
439         register_netdevice_notifier(&lapbeth_dev_notifier);
440
441         printk(banner);
442
443         return 0;
444 }
445 module_init(lapbeth_init_driver);
446
447 static void __exit lapbeth_cleanup_driver(void)
448 {
449         struct lapbethdev *lapbeth;
450         struct list_head *entry, *tmp;
451
452         dev_remove_pack(&lapbeth_packet_type);
453         unregister_netdevice_notifier(&lapbeth_dev_notifier);
454
455         rtnl_lock();
456         list_for_each_safe(entry, tmp, &lapbeth_devices) {
457                 lapbeth = list_entry(entry, struct lapbethdev, node);
458
459                 dev_put(lapbeth->ethdev);
460                 unregister_netdevice(lapbeth->axdev);
461         }
462         rtnl_unlock();
463 }
464 module_exit(lapbeth_cleanup_driver);
465
466 MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
467 MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
468 MODULE_LICENSE("GPL");