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/config.h>
58 #include <linux/errno.h>
59 #include <linux/types.h>
60 #include <linux/socket.h>
61 #include <linux/in.h>
62 #include <linux/kernel.h>
63 #include <linux/string.h>
64 #include <linux/net.h>
65 #include <net/ax25.h>
66 #include <linux/inet.h>
67 #include <linux/netdevice.h>
68 #include <linux/if_ether.h>
69 #include <linux/if_arp.h>
70 #include <linux/skbuff.h>
71 #include <net/sock.h>
72 #include <asm/system.h>
73 #include <asm/uaccess.h>
74 #include <linux/mm.h>
75 #include <linux/interrupt.h>
76 #include <linux/notifier.h>
77 #include <linux/proc_fs.h>
78 #include <linux/seq_file.h>
79 #include <linux/stat.h>
80 #include <linux/netfilter.h>
81 #include <linux/module.h>
82 #include <linux/init.h>
83 #include <linux/rtnetlink.h>
84
85 #include <net/ip.h>
86 #include <net/arp.h>
87
88 #include <linux/bpqether.h>
89
90 static char banner[] __initdata = KERN_INFO "AX.25: bpqether driver version 004\n";
91
92 static unsigned char ax25_bcast[AX25_ADDR_LEN] =
93 {'Q' << 1, 'S' << 1, 'T' << 1, ' ' << 1, ' ' << 1, ' ' << 1, '' << 1};
94 static unsigned char ax25_defaddr[AX25_ADDR_LEN] =
95 {'L' << 1, 'I' << 1, 'N' << 1, 'U' << 1, 'X' << 1, ' ' << 1, '1' << 1};
96
97 static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};
98
99 static char bpq_eth_addr[6];
100
101 static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *);
102 static int bpq_device_event(struct notifier_block *, unsigned long, void *);
103 static const char *bpq_print_ethaddr(const unsigned char *);
104
105 static struct packet_type bpq_packet_type = {
106 .type = __constant_htons(ETH_P_BPQ),
107 .func = bpq_rcv,
108 };
109
110 static struct notifier_block bpq_dev_notifier = {
111 .notifier_call =bpq_device_event,
112 };
113
114
115 #define MAXBPQDEV 100
116
117 struct bpqdev {
118 struct list_head bpq_list; /* list of bpq devices chain */
119 struct net_device *ethdev; /* link to ethernet device */
120 struct net_device *axdev; /* bpq device (bpq#) */
121 struct net_device_stats stats; /* some statistics */
122 char dest_addr[6]; /* ether destination address */
123 char acpt_addr[6]; /* accept ether frames from this address only */
124 };
125
126 static LIST_HEAD(bpq_devices);
127
128
129 /* ------------------------------------------------------------------------ */
130
131
132 /*
133 * Get the ethernet device for a BPQ device
134 */
135 static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
136 {
137 struct bpqdev *bpq = (struct bpqdev *) dev->priv;
138
139 return bpq ? bpq->ethdev : NULL;
140 }
141
142 /*
143 * Get the BPQ device for the ethernet device
144 */
145 static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
146 {
147 struct bpqdev *bpq;
148
149 list_for_each_entry(bpq, &bpq_devices, bpq_list) {
150 if (bpq->ethdev == dev)
151 return bpq->axdev;
152 }
153 return NULL;
154 }
155
156 static inline int dev_is_ethdev(struct net_device *dev)
157 {
158 return (
159 dev->type == ARPHRD_ETHER
160 && strncmp(dev->name, "dummy", 5)
161 );
162 }
163
164 /* ------------------------------------------------------------------------ */
165
166
167 /*
168 * Receive an AX.25 frame via an ethernet interface.
169 */
170 static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype)
171 {
172 int len;
173 char * ptr;
174 struct ethhdr *eth;
175 struct bpqdev *bpq;
176
177 if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
178 return NET_RX_DROP;
179
180 if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
181 goto drop;
182
183 rcu_read_lock();
184 dev = bpq_get_ax25_dev(dev);
185
186 if (dev == NULL || !netif_running(dev))
187 goto drop_unlock;
188
189 /*
190 * if we want to accept frames from just one ethernet device
191 * we check the source address of the sender.
192 */
193
194 bpq = (struct bpqdev *)dev->priv;
195
196 eth = eth_hdr(skb);
197
198 if (!(bpq->acpt_addr[0] & 0x01) &&
199 memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
200 goto drop_unlock;
201
202 if (skb_cow(skb, sizeof(struct ethhdr)))
203 goto drop_unlock;
204
205 len = skb->data[0] + skb->data[1] * 256 - 5;
206
207 skb_pull(skb, 2); /* Remove the length bytes */
208 skb_trim(skb, len); /* Set the length of the data */
209
210 bpq->stats.rx_packets++;
211 bpq->stats.rx_bytes += len;
212
213 ptr = skb_push(skb, 1);
214 *ptr = 0;
215
216 skb->dev = dev;
217 skb->protocol = htons(ETH_P_AX25);
218 skb->mac.raw = skb->data;
219 skb->pkt_type = PACKET_HOST;
220
221 netif_rx(skb);
222 dev->last_rx = jiffies;
223 unlock:
224
225 rcu_read_unlock();
226
227 return 0;
228 drop_unlock:
229 kfree_skb(skb);
230 goto unlock;
231
232 drop:
233 kfree_skb(skb);
234 return 0;
235 }
236
237 /*
238 * Send an AX.25 frame via an ethernet interface
239 */
240 static int bpq_xmit(struct sk_buff *skb, struct net_device *dev)
241 {
242 struct sk_buff *newskb;
243 unsigned char *ptr;
244 struct bpqdev *bpq;
245 int size;
246
247 /*
248 * Just to be *really* sure not to send anything if the interface
249 * is down, the ethernet device may have gone.
250 */
251 if (!netif_running(dev)) {
252 kfree_skb(skb);
253 return -ENODEV;
254 }
255
256 skb_pull(skb, 1);
257 size = skb->len;
258
259 /*
260 * The AX.25 code leaves enough room for the ethernet header, but
261 * sendto() does not.
262 */
263 if (skb_headroom(skb) < AX25_BPQ_HEADER_LEN) { /* Ough! */
264 if ((newskb = skb_realloc_headroom(skb, AX25_BPQ_HEADER_LEN)) == NULL) {
265 printk(KERN_WARNING "bpqether: out of memory\n");
266 kfree_skb(skb);
267 return -ENOMEM;
268 }
269
270 if (skb->sk != NULL)
271 skb_set_owner_w(newskb, skb->sk);
272
273 kfree_skb(skb);
274 skb = newskb;
275 }
276
277 skb->protocol = htons(ETH_P_AX25);
278
279 ptr = skb_push(skb, 2);
280
281 *ptr++ = (size + 5) % 256;
282 *ptr++ = (size + 5) / 256;
283
284 bpq = (struct bpqdev *)dev->priv;
285
286 if ((dev = bpq_get_ether_dev(dev)) == NULL) {
287 bpq->stats.tx_dropped++;
288 kfree_skb(skb);
289 return -ENODEV;
290 }
291
292 skb->dev = dev;
293 skb->nh.raw = skb->data;
294 dev->hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
295 bpq->stats.tx_packets++;
296 bpq->stats.tx_bytes+=skb->len;
297
298 dev_queue_xmit(skb);
299 netif_wake_queue(dev);
300 return 0;
301 }
302
303 /*
304 * Statistics
305 */
306 static struct net_device_stats *bpq_get_stats(struct net_device *dev)
307 {
308 struct bpqdev *bpq = (struct bpqdev *) dev->priv;
309
310 return &bpq->stats;
311 }
312
313 /*
314 * Set AX.25 callsign
315 */
316 static int bpq_set_mac_address(struct net_device *dev, void *addr)
317 {
318 struct sockaddr *sa = (struct sockaddr *)addr;
319
320 memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);
321
322 return 0;
323 }
324
325 /* Ioctl commands
326 *
327 * SIOCSBPQETHOPT reserved for enhancements
328 * SIOCSBPQETHADDR set the destination and accepted
329 * source ethernet address (broadcast
330 * or multicast: accept all)
331 */
332 static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
333 {
334 struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
335 struct bpqdev *bpq = dev->priv;
336 struct bpq_req req;
337
338 if (!capable(CAP_NET_ADMIN))
339 return -EPERM;
340
341 if (bpq == NULL) /* woops! */
342 return -ENODEV;
343
344 switch (cmd) {
345 case SIOCSBPQETHOPT:
346 if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
347 return -EFAULT;
348 switch (req.cmd) {
349 case SIOCGBPQETHPARAM:
350 case SIOCSBPQETHPARAM:
351 default:
352 return -EINVAL;
353 }
354
355 break;
356
357 case SIOCSBPQETHADDR:
358 if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
359 return -EFAULT;
360 if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
361 return -EFAULT;
362 break;
363
364 default:
365 return -EINVAL;
366 }
367
368 return 0;
369 }
370
371 /*
372 * open/close a device
373 */
374 static int bpq_open(struct net_device *dev)
375 {
376 netif_start_queue(dev);
377 return 0;
378 }
379
380 static int bpq_close(struct net_device *dev)
381 {
382 netif_stop_queue(dev);
383 return 0;
384 }
385
386
387 /* ------------------------------------------------------------------------ */
388
389
390 /*
391 * Proc filesystem
392 */
393 static const char * bpq_print_ethaddr(const unsigned char *e)
394 {
395 static char buf[18];
396
397 sprintf(buf, "%2.2X:%2.2X:%2.2X:%2.2X:%2.2X:%2.2X",
398 e[0], e[1], e[2], e[3], e[4], e[5]);
399
400 return buf;
401 }
402
403 static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
404 {
405 int i = 1;
406 struct bpqdev *bpqdev;
407
408 rcu_read_lock();
409
410 if (*pos == 0)
411 return SEQ_START_TOKEN;
412
413 list_for_each_entry(bpqdev, &bpq_devices, bpq_list) {
414 if (i == *pos)
415 return bpqdev;
416 }
417 return NULL;
418 }
419
420 static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
421 {
422 struct list_head *p;
423
424 ++*pos;
425
426 if (v == SEQ_START_TOKEN)
427 p = bpq_devices.next;
428 else
429 p = ((struct bpqdev *)v)->bpq_list.next;
430
431 return (p == &bpq_devices) ? NULL
432 : list_entry(p, struct bpqdev, bpq_list);
433 }
434
435 static void bpq_seq_stop(struct seq_file *seq, void *v)
436 {
437 rcu_read_unlock();
438 }
439
440
441 static int bpq_seq_show(struct seq_file *seq, void *v)
442 {
443 if (v == SEQ_START_TOKEN)
444 seq_puts(seq,
445 "dev ether destination accept from\n");
446 else {
447 const struct bpqdev *bpqdev = v;
448
449 seq_printf(seq, "%-5s %-10s %s ",
450 bpqdev->axdev->name, bpqdev->ethdev->name,
451 bpq_print_ethaddr(bpqdev->dest_addr));
452
453 seq_printf(seq, "%s\n",
454 (bpqdev->acpt_addr[0] & 0x01) ? "*"
455 : bpq_print_ethaddr(bpqdev->acpt_addr));
456
457 }
458 return 0;
459 }
460
461 static struct seq_operations bpq_seqops = {
462 .start = bpq_seq_start,
463 .next = bpq_seq_next,
464 .stop = bpq_seq_stop,
465 .show = bpq_seq_show,
466 };
467
468 static int bpq_info_open(struct inode *inode, struct file *file)
469 {
470 return seq_open(file, &bpq_seqops);
471 }
472
473 static struct file_operations bpq_info_fops = {
474 .owner = THIS_MODULE,
475 .open = bpq_info_open,
476 .read = seq_read,
477 .llseek = seq_lseek,
478 .release = seq_release,
479 };
480
481
482 /* ------------------------------------------------------------------------ */
483
484
485 static void bpq_setup(struct net_device *dev)
486 {
487
488 dev->hard_start_xmit = bpq_xmit;
489 dev->open = bpq_open;
490 dev->stop = bpq_close;
491 dev->set_mac_address = bpq_set_mac_address;
492 dev->get_stats = bpq_get_stats;
493 dev->do_ioctl = bpq_ioctl;
494 dev->destructor = free_netdev;
495
496 memcpy(dev->broadcast, ax25_bcast, AX25_ADDR_LEN);
497 memcpy(dev->dev_addr, ax25_defaddr, AX25_ADDR_LEN);
498
499 dev->flags = 0;
500
501 #if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
502 dev->hard_header = ax25_encapsulate;
503 dev->rebuild_header = ax25_rebuild_header;
504 #endif
505
506 dev->type = ARPHRD_AX25;
507 dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
508 dev->mtu = AX25_DEF_PACLEN;
509 dev->addr_len = AX25_ADDR_LEN;
510
511 }
512
513 /*
514 * Setup a new device.
515 */
516 static int bpq_new_device(struct net_device *edev)
517 {
518 int err;
519 struct net_device *ndev;
520 struct bpqdev *bpq;
521
522 ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
523 bpq_setup);
524 if (!ndev)
525 return -ENOMEM;
526
527
528 bpq = ndev->priv;
529 dev_hold(edev);
530 bpq->ethdev = edev;
531 bpq->axdev = ndev;
532
533 memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
534 memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));
535
536 err = dev_alloc_name(ndev, ndev->name);
537 if (err < 0)
538 goto error;
539
540 err = register_netdevice(ndev);
541 if (err)
542 goto error;
543
544 /* List protected by RTNL */
545 list_add_rcu(&bpq->bpq_list, &bpq_devices);
546 return 0;
547
548 error:
549 dev_put(edev);
550 free_netdev(ndev);
551 return err;
552
553 }
554
555 static void bpq_free_device(struct net_device *ndev)
556 {
557 struct bpqdev *bpq = ndev->priv;
558
559 dev_put(bpq->ethdev);
560 list_del_rcu(&bpq->bpq_list);
561
562 unregister_netdevice(ndev);
563 }
564
565 /*
566 * Handle device status changes.
567 */
568 static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
569 {
570 struct net_device *dev = (struct net_device *)ptr;
571
572 if (!dev_is_ethdev(dev))
573 return NOTIFY_DONE;
574
575 rcu_read_lock();
576
577 switch (event) {
578 case NETDEV_UP: /* new ethernet device -> new BPQ interface */
579 if (bpq_get_ax25_dev(dev) == NULL)
580 bpq_new_device(dev);
581 break;
582
583 case NETDEV_DOWN: /* ethernet device closed -> close BPQ interface */
584 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
585 dev_close(dev);
586 break;
587
588 case NETDEV_UNREGISTER: /* ethernet device removed -> free BPQ interface */
589 if ((dev = bpq_get_ax25_dev(dev)) != NULL)
590 bpq_free_device(dev);
591 break;
592 default:
593 break;
594 }
595 rcu_read_unlock();
596
597 return NOTIFY_DONE;
598 }
599
600
601 /* ------------------------------------------------------------------------ */
602
603 /*
604 * Initialize driver. To be called from af_ax25 if not compiled as a
605 * module
606 */
607 static int __init bpq_init_driver(void)
608 {
609 #ifdef CONFIG_PROC_FS
610 if (!proc_net_fops_create("bpqether", S_IRUGO, &bpq_info_fops)) {
611 printk(KERN_ERR
612 "bpq: cannot create /proc/net/bpqether entry.\n");
613 return -ENOENT;
614 }
615 #endif /* CONFIG_PROC_FS */
616
617 dev_add_pack(&bpq_packet_type);
618
619 register_netdevice_notifier(&bpq_dev_notifier);
620
621 printk(banner);
622
623 return 0;
624 }
625
626 static void __exit bpq_cleanup_driver(void)
627 {
628 struct bpqdev *bpq;
629
630 dev_remove_pack(&bpq_packet_type);
631
632 unregister_netdevice_notifier(&bpq_dev_notifier);
633
634 proc_net_remove("bpqether");
635
636 rtnl_lock();
637 while (!list_empty(&bpq_devices)) {
638 bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
639 bpq_free_device(bpq->axdev);
640 }
641 rtnl_unlock();
642 }
643
644 MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
645 MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
646 MODULE_LICENSE("GPL");
647 module_init(bpq_init_driver);
648 module_exit(bpq_cleanup_driver);
649
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