Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
24
25#include <linux/errno.h>
26#include <linux/types.h>
27#include <linux/socket.h>
28#include <linux/in.h>
29#include <linux/slab.h>
30#include <linux/kernel.h>
31#include <linux/string.h>
32#include <linux/net.h>
33#include <linux/inet.h>
34#include <linux/netdevice.h>
35#include <linux/if_arp.h>
36#include <linux/skbuff.h>
37#include <net/sock.h>
38#include <asm/system.h>
39#include <asm/uaccess.h>
40#include <linux/mm.h>
41#include <linux/interrupt.h>
42#include <linux/notifier.h>
43#include <linux/stat.h>
44#include <linux/netfilter.h>
45#include <linux/module.h>
46#include <linux/lapb.h>
47#include <linux/init.h>
48
49#include <net/x25device.h>
50
51static const u8 bcast_addr[6] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF };
52
53/* If this number is made larger, check that the temporary string buffer
54 * in lapbeth_new_device is large enough to store the probe device name.*/
55#define MAXLAPBDEV 100
56
57struct lapbethdev {
58 struct list_head node;
59 struct net_device *ethdev; /* link to ethernet device */
60 struct net_device *axdev; /* lapbeth device (lapb#) */
61};
62
63static LIST_HEAD(lapbeth_devices);
64
65/* ------------------------------------------------------------------------ */
66
67/*
68 * Get the LAPB device for the ethernet device
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) {
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
88/*
89 * Receive a LAPB frame via an ethernet interface.
90 */
91static int lapbeth_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
92{
93 int len, err;
94 struct lapbethdev *lapbeth;
95
96 if (dev_net(dev) != &init_net)
97 goto drop;
98
99 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
100 return NET_RX_DROP;
101
102 if (!pskb_may_pull(skb, 2))
103 goto drop;
104
105 rcu_read_lock();
106 lapbeth = lapbeth_get_x25_dev(dev);
107 if (!lapbeth)
108 goto drop_unlock;
109 if (!netif_running(lapbeth->axdev))
110 goto drop_unlock;
111
112 len = skb->data[0] + skb->data[1] * 256;
113 dev->stats.rx_packets++;
114 dev->stats.rx_bytes += len;
115
116 skb_pull(skb, 2); /* Remove the length bytes */
117 skb_trim(skb, len); /* Set the length of the data */
118
119 if ((err = lapb_data_received(lapbeth->axdev, skb)) != LAPB_OK) {
120 printk(KERN_DEBUG "lapbether: lapb_data_received err - %d\n", err);
121 goto drop_unlock;
122 }
123out:
124 rcu_read_unlock();
125 return 0;
126drop_unlock:
127 kfree_skb(skb);
128 goto out;
129drop:
130 kfree_skb(skb);
131 return 0;
132}
133
134static int lapbeth_data_indication(struct net_device *dev, struct sk_buff *skb)
135{
136 unsigned char *ptr;
137
138 skb_push(skb, 1);
139
140 if (skb_cow(skb, 1))
141 return NET_RX_DROP;
142
143 ptr = skb->data;
144 *ptr = X25_IFACE_DATA;
145
146 skb->protocol = x25_type_trans(skb, dev);
147 return netif_rx(skb);
148}
149
150/*
151 * Send a LAPB frame via an ethernet interface
152 */
153static netdev_tx_t lapbeth_xmit(struct sk_buff *skb,
154 struct net_device *dev)
155{
156 int err;
157
158 /*
159 * Just to be *really* sure not to send anything if the interface
160 * is down, the ethernet device may have gone.
161 */
162 if (!netif_running(dev))
163 goto drop;
164
165 switch (skb->data[0]) {
166 case X25_IFACE_DATA:
167 break;
168 case X25_IFACE_CONNECT:
169 if ((err = lapb_connect_request(dev)) != LAPB_OK)
170 pr_err("lapb_connect_request error: %d\n", err);
171 goto drop;
172 case X25_IFACE_DISCONNECT:
173 if ((err = lapb_disconnect_request(dev)) != LAPB_OK)
174 pr_err("lapb_disconnect_request err: %d\n", err);
175 /* Fall thru */
176 default:
177 goto drop;
178 }
179
180 skb_pull(skb, 1);
181
182 if ((err = lapb_data_request(dev, skb)) != LAPB_OK) {
183 pr_err("lapb_data_request error - %d\n", err);
184 goto drop;
185 }
186out:
187 return NETDEV_TX_OK;
188drop:
189 kfree_skb(skb);
190 goto out;
191}
192
193static void lapbeth_data_transmit(struct net_device *ndev, struct sk_buff *skb)
194{
195 struct lapbethdev *lapbeth = netdev_priv(ndev);
196 unsigned char *ptr;
197 struct net_device *dev;
198 int size = skb->len;
199
200 skb->protocol = htons(ETH_P_X25);
201
202 ptr = skb_push(skb, 2);
203
204 *ptr++ = size % 256;
205 *ptr++ = size / 256;
206
207 ndev->stats.tx_packets++;
208 ndev->stats.tx_bytes += size;
209
210 skb->dev = dev = lapbeth->ethdev;
211
212 dev_hard_header(skb, dev, ETH_P_DEC, bcast_addr, NULL, 0);
213
214 dev_queue_xmit(skb);
215}
216
217static void lapbeth_connected(struct net_device *dev, int reason)
218{
219 unsigned char *ptr;
220 struct sk_buff *skb = dev_alloc_skb(1);
221
222 if (!skb) {
223 pr_err("out of memory\n");
224 return;
225 }
226
227 ptr = skb_put(skb, 1);
228 *ptr = X25_IFACE_CONNECT;
229
230 skb->protocol = x25_type_trans(skb, dev);
231 netif_rx(skb);
232}
233
234static void lapbeth_disconnected(struct net_device *dev, int reason)
235{
236 unsigned char *ptr;
237 struct sk_buff *skb = dev_alloc_skb(1);
238
239 if (!skb) {
240 pr_err("out of memory\n");
241 return;
242 }
243
244 ptr = skb_put(skb, 1);
245 *ptr = X25_IFACE_DISCONNECT;
246
247 skb->protocol = x25_type_trans(skb, dev);
248 netif_rx(skb);
249}
250
251/*
252 * Set AX.25 callsign
253 */
254static int lapbeth_set_mac_address(struct net_device *dev, void *addr)
255{
256 struct sockaddr *sa = addr;
257 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
258 return 0;
259}
260
261
262static const struct lapb_register_struct lapbeth_callbacks = {
263 .connect_confirmation = lapbeth_connected,
264 .connect_indication = lapbeth_connected,
265 .disconnect_confirmation = lapbeth_disconnected,
266 .disconnect_indication = lapbeth_disconnected,
267 .data_indication = lapbeth_data_indication,
268 .data_transmit = lapbeth_data_transmit,
269};
270
271/*
272 * open/close a device
273 */
274static int lapbeth_open(struct net_device *dev)
275{
276 int err;
277
278 if ((err = lapb_register(dev, &lapbeth_callbacks)) != LAPB_OK) {
279 pr_err("lapb_register error: %d\n", err);
280 return -ENODEV;
281 }
282
283 netif_start_queue(dev);
284 return 0;
285}
286
287static int lapbeth_close(struct net_device *dev)
288{
289 int err;
290
291 netif_stop_queue(dev);
292
293 if ((err = lapb_unregister(dev)) != LAPB_OK)
294 pr_err("lapb_unregister error: %d\n", err);
295
296 return 0;
297}
298
299/* ------------------------------------------------------------------------ */
300
301static const struct net_device_ops lapbeth_netdev_ops = {
302 .ndo_open = lapbeth_open,
303 .ndo_stop = lapbeth_close,
304 .ndo_start_xmit = lapbeth_xmit,
305 .ndo_set_mac_address = lapbeth_set_mac_address,
306};
307
308static void lapbeth_setup(struct net_device *dev)
309{
310 dev->netdev_ops = &lapbeth_netdev_ops;
311 dev->destructor = free_netdev;
312 dev->type = ARPHRD_X25;
313 dev->hard_header_len = 3;
314 dev->mtu = 1000;
315 dev->addr_len = 0;
316}
317
318/*
319 * Setup a new device.
320 */
321static int lapbeth_new_device(struct net_device *dev)
322{
323 struct net_device *ndev;
324 struct lapbethdev *lapbeth;
325 int rc = -ENOMEM;
326
327 ASSERT_RTNL();
328
329 ndev = alloc_netdev(sizeof(*lapbeth), "lapb%d",
330 lapbeth_setup);
331 if (!ndev)
332 goto out;
333
334 lapbeth = netdev_priv(ndev);
335 lapbeth->axdev = ndev;
336
337 dev_hold(dev);
338 lapbeth->ethdev = dev;
339
340 rc = -EIO;
341 if (register_netdevice(ndev))
342 goto fail;
343
344 list_add_rcu(&lapbeth->node, &lapbeth_devices);
345 rc = 0;
346out:
347 return rc;
348fail:
349 dev_put(dev);
350 free_netdev(ndev);
351 kfree(lapbeth);
352 goto out;
353}
354
355/*
356 * Free a lapb network device.
357 */
358static void lapbeth_free_device(struct lapbethdev *lapbeth)
359{
360 dev_put(lapbeth->ethdev);
361 list_del_rcu(&lapbeth->node);
362 unregister_netdevice(lapbeth->axdev);
363}
364
365/*
366 * Handle device status changes.
367 *
368 * Called from notifier with RTNL held.
369 */
370static int lapbeth_device_event(struct notifier_block *this,
371 unsigned long event, void *ptr)
372{
373 struct lapbethdev *lapbeth;
374 struct net_device *dev = ptr;
375
376 if (dev_net(dev) != &init_net)
377 return NOTIFY_DONE;
378
379 if (!dev_is_ethdev(dev))
380 return NOTIFY_DONE;
381
382 switch (event) {
383 case NETDEV_UP:
384 /* New ethernet device -> new LAPB interface */
385 if (lapbeth_get_x25_dev(dev) == NULL)
386 lapbeth_new_device(dev);
387 break;
388 case NETDEV_DOWN:
389 /* ethernet device closed -> close LAPB interface */
390 lapbeth = lapbeth_get_x25_dev(dev);
391 if (lapbeth)
392 dev_close(lapbeth->axdev);
393 break;
394 case NETDEV_UNREGISTER:
395 /* ethernet device disappears -> remove LAPB interface */
396 lapbeth = lapbeth_get_x25_dev(dev);
397 if (lapbeth)
398 lapbeth_free_device(lapbeth);
399 break;
400 }
401
402 return NOTIFY_DONE;
403}
404
405/* ------------------------------------------------------------------------ */
406
407static struct packet_type lapbeth_packet_type __read_mostly = {
408 .type = cpu_to_be16(ETH_P_DEC),
409 .func = lapbeth_rcv,
410};
411
412static struct notifier_block lapbeth_dev_notifier = {
413 .notifier_call = lapbeth_device_event,
414};
415
416static const char banner[] __initconst =
417 KERN_INFO "LAPB Ethernet driver version 0.02\n";
418
419static int __init lapbeth_init_driver(void)
420{
421 dev_add_pack(&lapbeth_packet_type);
422
423 register_netdevice_notifier(&lapbeth_dev_notifier);
424
425 printk(banner);
426
427 return 0;
428}
429module_init(lapbeth_init_driver);
430
431static void __exit lapbeth_cleanup_driver(void)
432{
433 struct lapbethdev *lapbeth;
434 struct list_head *entry, *tmp;
435
436 dev_remove_pack(&lapbeth_packet_type);
437 unregister_netdevice_notifier(&lapbeth_dev_notifier);
438
439 rtnl_lock();
440 list_for_each_safe(entry, tmp, &lapbeth_devices) {
441 lapbeth = list_entry(entry, struct lapbethdev, node);
442
443 dev_put(lapbeth->ethdev);
444 unregister_netdevice(lapbeth->axdev);
445 }
446 rtnl_unlock();
447}
448module_exit(lapbeth_cleanup_driver);
449
450MODULE_AUTHOR("Jonathan Naylor <g4klx@g4klx.demon.co.uk>");
451MODULE_DESCRIPTION("The unofficial LAPB over Ethernet driver");
452MODULE_LICENSE("GPL");