1 /*
2 * G8BPQ compatible "AX.25 via ethernet" driver release 004
3 *
4 * This code REQUIRES 2.0.0 or higher/ NET3.029
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 AX.25 over Ethernet
13 * using G8BPQ encapsulation. It has been extracted from the protocol
14 * implementation because
15 *
16 * - things got unreadable within the protocol stack
17 * - to cure the protocol stack from "feature-ism"
18 * - a protocol implementation shouldn't need to know on
19 * which hardware it is running
20 * - user-level programs like the AX.25 utilities shouldn't
21 * need to know about the hardware.
22 * - IP over ethernet encapsulated AX.25 was impossible
23 * - rxecho.c did not work
24 * - to have room for extensions
25 * - it just deserves to "live" as an own driver
26 *
27 * This driver can use any ethernet destination address, and can be
28 * limited to accept frames from one dedicated ethernet card only.
29 *
30 * Note that the driver sets up the BPQ devices automagically on
31 * startup or (if started before the "insmod" of an ethernet device)
32 * on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
33 * the ethernet device (in fact: as soon as another ethernet or bpq
34 * device gets "ifconfig"ured).
35 *
36 * I have heard that several people are thinking of experiments
37 * with highspeed packet radio using existing ethernet cards.
38 * Well, this driver is prepared for this purpose, just add
39 * your tx key control and a txdelay / tailtime algorithm,
40 * probably some buffering, and /voila/...
41 *
42 * History
43 * BPQ 001 Joerg(DL1BKE) Extracted BPQ code from AX.25
44 * protocol stack and added my own
45 * yet existing patches
46 * BPQ 002 Joerg(DL1BKE) Scan network device list on
47 * startup.
48 * BPQ 003 Joerg(DL1BKE) Ethernet destination address
49 * and accepted source address
50 * can be configured by an ioctl()
51 * call.
52 * Fixed to match Linux networking
53 * changes - 2.1.15.
54 * BPQ 004 Joerg(DL1BKE) Fixed to not lock up on ifconfig.
55 */
56
57 #include <linux/errno.h>
58 #include <linux/types.h>
59 #include <linux/socket.h>
60 #include <linux/in.h>
61 #include <linux/kernel.h>
62 #include <linux/string.h>
63 #include <linux/net.h>
64 #include <net/ax25.h>
65 #include <linux/inet.h>
66 #include <linux/netdevice.h>
67 #include <linux/etherdevice.h>
68 #include <linux/if_arp.h>
69 #include <linux/skbuff.h>
70 #include <net/sock.h>
71 #include <asm/system.h>
72 #include <asm/uaccess.h>
73 #include <linux/mm.h>
74 #include <linux/interrupt.h>
75 #include <linux/notifier.h>
76 #include <linux/proc_fs.h>
77 #include <linux/seq_file.h>
78 #include <linux/stat.h>
79 #include <linux/netfilter.h>
80 #include <linux/module.h>
81 #include <linux/init.h>
82 #include <linux/rtnetlink.h>
83
84 #include <net/ip.h>
85 #include <net/arp.h>
86 #include <net/net_namespace.h>
87
88 #include <linux/bpqether.h>
89
90 static const char banner[] __initdata = KERN_INFO \
91 "AX.25: bpqether driver version 004\n";
92
93 static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
94
95 static char bpq_eth_addr[6];
96
97 static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
98 static int bpq_device_event(struct notifier_block *, unsigned long, void *);
99
100 static struct packet_type bpq_packet_type __read_mostly = {
101 .type = cpu_to_be16(ETH_P_BPQ),
102 .func = bpq_rcv,
103 };
104
105 static struct notifier_block bpq_dev_notifier = {
106 .notifier_call =bpq_device_event,
107 };
108
109
110 struct bpqdev {
111 struct list_head bpq_list; /* list of bpq devices chain */
112 struct net_device *ethdev; /* link to ethernet device */
113 struct net_device *axdev; /* bpq device (bpq#) */
114 char dest_addr[6]; /* ether destination address */
115 char acpt_addr[6]; /* accept ether frames from this address only */
116 };
117
118 static LIST_HEAD(bpq_devices);
119
120 /*
121 * bpqether network devices are paired with ethernet devices below them, so
122 * form a special "super class" of normal ethernet devices; split their locks
123 * off into a separate class since they always nest.
124 */
125 static struct lock_class_key bpq_netdev_xmit_lock_key;
126 static struct lock_class_key bpq_netdev_addr_lock_key;
127
128 static void bpq_set_lockdep_class_one(struct net_device *dev,
129 struct netdev_queue *txq,
130 void *_unused)
131 {
132 lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
133 }
134
135 static void bpq_set_lockdep_class(struct net_device *dev)
136 {
137 lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
138 netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
139 }
140
141 /* ------------------------------------------------------------------------ */
142
143
144 /*
145 * Get the ethernet device for a BPQ device
146 */
147 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
148 {
149 struct bpqdev *bpq = netdev_priv(dev);
150
151 return bpq ? bpq->ethdev : NULL;
152 }
153
154 /*
155 * Get the BPQ device for the ethernet device
156 */
157 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
158 {
159 struct bpqdev *bpq;
160
161 list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
162 if (bpq->ethdev == dev)
163 return bpq->axdev;
164 }
165 return NULL;
166 }
167
168 static inline int dev_is_ethdev(struct net_device *dev)
169 {
170 return (
171 dev->type == ARPHRD_ETHER
172 && strncmp(dev->name, "dummy", 5)
173 );
174 }
175
176 /* ------------------------------------------------------------------------ */
177
178
179 /*
180 * Receive an AX.25 frame via an ethernet interface.
181 */
182 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
183 {
184 int len;
185 char * ptr;
186 struct ethhdr *eth;
187 struct bpqdev *bpq;
188
189 if (dev_net(dev) != &init_net)
190 goto drop;
191
192 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
193 return NET_RX_DROP;
194
195 if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
196 goto drop;
197
198 rcu_read_lock();
199 dev = bpq_get_ax25_dev(dev);
200
201 if (dev == NULL || !netif_running(dev))
202 goto drop_unlock;
203
204 /*
205 * if we want to accept frames from just one ethernet device
206 * we check the source address of the sender.
207 */
208
209 bpq = netdev_priv(dev);
210
211 eth = eth_hdr(skb);
212
213 if (!(bpq->acpt_addr[0] & 0x01) &&
214 memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
215 goto drop_unlock;
216
217 if (skb_cow(skb, sizeof(struct ethhdr)))
218 goto drop_unlock;
219
220 len = skb->data[0] + skb->data[1] * 256 - 5;
221
222 skb_pull(skb, 2); /* Remove the length bytes */
223 skb_trim(skb, len); /* Set the length of the data */
224
225 dev->stats.rx_packets++;
226 dev->stats.rx_bytes += len;
227
228 ptr = skb_push(skb, 1);
229 *ptr = 0;
230
231 skb->protocol = ax25_type_trans(skb, dev);
232 netif_rx(skb);
233 unlock:
234
235 rcu_read_unlock();
236
237 return 0;
238 drop_unlock:
239 kfree_skb(skb);
240 goto unlock;
241
242 drop:
243 kfree_skb(skb);
244 return 0;
245 }
246
247 /*
248 * Send an AX.25 frame via an ethernet interface
249 */
250 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
251 {
252 struct sk_buff *newskb;
253 unsigned char *ptr;
254 struct bpqdev *bpq;
255 int size;
256
257 /*
258 * Just to be *really* sure not to send anything if the interface
259 * is down, the ethernet device may have gone.
260 */
261 if (!netif_running(dev)) {
262 kfree_skb(skb);
263 return NETDEV_TX_OK;
264 }
265
266 skb_pull(skb, 1);
267 size = skb->len;
268
269 /*
270 * The AX.25 code leaves enough room for the ethernet header, but
271 * sendto() does not.
272 */
273 if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) { /* Ough! */
274 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
275 printk(KERN_WARNING "bpqether: out of memory\n");
276 kfree_skb(skb);
277 return NETDEV_TX_OK;
278 }
279
280 if (skb->sk != NULL)
281 skb_set_owner_w(newskb, skb->sk);
282
283 kfree_skb(skb);
284 skb = newskb;
285 }
286
287 ptr = skb_push(skb, 2);
288
289 *ptr++ = (size + 5) % 256;
290 *ptr++ = (size + 5) / 256;
291
292 bpq = netdev_priv(dev);
293
294 if ((dev = bpq_get_ether_dev(dev)) == NULL) {
295 dev->stats.tx_dropped++;
296 kfree_skb(skb);
297 return NETDEV_TX_OK;
298 }
299
300 skb->protocol = ax25_type_trans(skb, dev);
301 skb_reset_network_header(skb);
302 dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
303 dev->stats.tx_packets++;
304 dev->stats.tx_bytes+=skb->len;
305
306 dev_queue_xmit(skb);
307 netif_wake_queue(dev);
308 return 0;
309 }
310
311 /*
312 * Set AX.25 callsign
313 */
314 static int bpq_set_mac_address(struct net_device *dev, void *addr)
315 {
316 struct sockaddr *sa = (struct sockaddr *)addr;
317
318 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
319
320 return 0;
321 }
322
323 /* Ioctl commands
324 *
325 * SIOCSBPQETHOPT reserved for enhancements
326 * SIOCSBPQETHADDR set the destination and accepted
327 * source ethernet address (broadcast
328 * or multicast: accept all)
329 */
330 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
331 {
332 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
333 struct bpqdev *bpq = netdev_priv(dev);
334 struct bpq_req req;
335
336 if (!capable(CAP_NET_ADMIN))
337 return -EPERM;
338
339 switch (cmd) {
340 case SIOCSBPQETHOPT:
341 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
342 return -EFAULT;
343 switch (req.cmd) {
344 case SIOCGBPQETHPARAM:
345 case SIOCSBPQETHPARAM:
346 default:
347 return -EINVAL;
348 }
349
350 break;
351
352 case SIOCSBPQETHADDR:
353 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
354 return -EFAULT;
355 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
356 return -EFAULT;
357 break;
358
359 default:
360 return -EINVAL;
361 }
362
363 return 0;
364 }
365
366 /*
367 * open/close a device
368 */
369 static int bpq_open(struct net_device *dev)
370 {
371 netif_start_queue(dev);
372 return 0;
373 }
374
375 static int bpq_close(struct net_device *dev)
376 {
377 netif_stop_queue(dev);
378 return 0;
379 }
380
381
382 /* ------------------------------------------------------------------------ */
383
384
385 /*
386 * Proc filesystem
387 */
388 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
389 __acquires(RCU)
390 {
391 int i = 1;
392 struct bpqdev *bpqdev;
393
394 rcu_read_lock();
395
396 if (*pos == 0)
397 return SEQ_START_TOKEN;
398
399 list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
400 if (i == *pos)
401 return bpqdev;
402 }
403 return NULL;
404 }
405
406 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
407 {
408 struct list_head *p;
409
410 ++*pos;
411
412 if (v == SEQ_START_TOKEN)
413 p = rcu_dereference(bpq_devices.next);
414 else
415 p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);
416
417 return (p == &bpq_devices) ? NULL
418 : list_entry(p, struct bpqdev, bpq_list);
419 }
420
421 static void bpq_seq_stop(struct seq_file *seq, void *v)
422 __releases(RCU)
423 {
424 rcu_read_unlock();
425 }
426
427
428 static int bpq_seq_show(struct seq_file *seq, void *v)
429 {
430 if (v == SEQ_START_TOKEN)
431 seq_puts(seq,
432 "dev ether destination accept from\n");
433 else {
434 const struct bpqdev *bpqdev = v;
435
436 seq_printf(seq, "%-5s %-10s %pM ",
437 bpqdev->axdev->name, bpqdev->ethdev->name,
438 bpqdev->dest_addr);
439
440 if (is_multicast_ether_addr(bpqdev->acpt_addr))
441 seq_printf(seq, "*\n");
442 else
443 seq_printf(seq, "%pM\n", bpqdev->acpt_addr);
444
445 }
446 return 0;
447 }
448
449 static const struct seq_operations bpq_seqops = {
450 .start = bpq_seq_start,
451 .next = bpq_seq_next,
452 .stop = bpq_seq_stop,
453 .show = bpq_seq_show,
454 };
455
456 static int bpq_info_open(struct inode *inode, struct file *file)
457 {
458 return seq_open(file, &bpq_seqops);
459 }
460
461 static const struct file_operations bpq_info_fops = {
462 .owner = THIS_MODULE,
463 .open = bpq_info_open,
464 .read = seq_read,
465 .llseek = seq_lseek,
466 .release = seq_release,
467 };
468
469
470 /* ------------------------------------------------------------------------ */
471
472 static const struct net_device_ops bpq_netdev_ops = {
473 .ndo_open = bpq_open,
474 .ndo_stop = bpq_close,
475 .ndo_start_xmit = bpq_xmit,
476 .ndo_set_mac_address = bpq_set_mac_address,
477 .ndo_do_ioctl = bpq_ioctl,
478 };
479
480 static void bpq_setup(struct net_device *dev)
481 {
482 dev->netdev_ops = &bpq_netdev_ops;
483 dev->destructor = free_netdev;
484
485 memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
486 memcpy(dev->dev_addr, &ax25_defaddr, AX25_ADDR_LEN);
487
488 dev->flags = 0;
489
490 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
491 dev->header_ops = &ax25_header_ops;
492 #endif
493
494 dev->type = ARPHRD_AX25;
495 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
496 dev->mtu = AX25_DEF_PACLEN;
497 dev->addr_len = AX25_ADDR_LEN;
498
499 }
500
501 /*
502 * Setup a new device.
503 */
504 static int bpq_new_device(struct net_device *edev)
505 {
506 int err;
507 struct net_device *ndev;
508 struct bpqdev *bpq;
509
510 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
511 bpq_setup);
512 if (!ndev)
513 return -ENOMEM;
514
515
516 bpq = netdev_priv(ndev);
517 dev_hold(edev);
518 bpq->ethdev = edev;
519 bpq->axdev = ndev;
520
521 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
522 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
523
524 err = dev_alloc_name(ndev, ndev->name);
525 if (err < 0)
526 goto error;
527
528 err = register_netdevice(ndev);
529 if (err)
530 goto error;
531 bpq_set_lockdep_class(ndev);
532
533 /* List protected by RTNL */
534 list_add_rcu(&bpq->bpq_list, &bpq_devices);
535 return 0;
536
537 error:
538 dev_put(edev);
539 free_netdev(ndev);
540 return err;
541
542 }
543
544 static void bpq_free_device(struct net_device *ndev)
545 {
546 struct bpqdev *bpq = netdev_priv(ndev);
547
548 dev_put(bpq->ethdev);
549 list_del_rcu(&bpq->bpq_list);
550
551 unregister_netdevice(ndev);
552 }
553
554 /*
555 * Handle device status changes.
556 */
557 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
558 {
559 struct net_device *dev = (struct net_device *)ptr;
560
561 if (dev_net(dev) != &init_net)
562 return NOTIFY_DONE;
563
564 if (!dev_is_ethdev(dev))
565 return NOTIFY_DONE;
566
567 switch (event) {
568 case NETDEV_UP: /* new ethernet device -> new BPQ interface */
569 if (bpq_get_ax25_dev(dev) == NULL)
570 bpq_new_device(dev);
571 break;
572
573 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
574 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
575 dev_close(dev);
576 break;
577
578 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
579 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
580 bpq_free_device(dev);
581 break;
582 default:
583 break;
584 }
585
586 return NOTIFY_DONE;
587 }
588
589
590 /* ------------------------------------------------------------------------ */
591
592 /*
593 * Initialize driver. To be called from af_ax25 if not compiled as a
594 * module
595 */
596 static int __init bpq_init_driver(void)
597 {
598 #ifdef CONFIG_PROC_FS
599 if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
600 printk(KERN_ERR
601 "bpq: cannot create /proc/net/bpqether entry.\n");
602 return -ENOENT;
603 }
604 #endif /* CONFIG_PROC_FS */
605
606 dev_add_pack(&bpq_packet_type);
607
608 register_netdevice_notifier(&bpq_dev_notifier);
609
610 printk(banner);
611
612 return 0;
613 }
614
615 static void __exit bpq_cleanup_driver(void)
616 {
617 struct bpqdev *bpq;
618
619 dev_remove_pack(&bpq_packet_type);
620
621 unregister_netdevice_notifier(&bpq_dev_notifier);
622
623 proc_net_remove(&init_net, "bpqether");
624
625 rtnl_lock();
626 while (!list_empty(&bpq_devices)) {
627 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
628 bpq_free_device(bpq->axdev);
629 }
630 rtnl_unlock();
631 }
632
633 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
634 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
635 MODULE_LICENSE("GPL");
636 module_init(bpq_init_driver);
637 module_exit(bpq_cleanup_driver);
638
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