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1da177e4 LT |
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) | |
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"); |