summaryrefslogtreecommitdiffstats
path: root/drivers/net/hamradio/bpqether.c
blob: fe893c91a01b904e24cd6027799a461fec8985bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
/*
 *	G8BPQ compatible "AX.25 via ethernet" driver release 004
 *
 *	This code REQUIRES 2.0.0 or higher/ NET3.029
 *
 *	This module:
 *		This module is free software; you can redistribute it and/or
 *		modify it under the terms of the GNU General Public License
 *		as published by the Free Software Foundation; either version
 *		2 of the License, or (at your option) any later version.
 *
 *	This is a "pseudo" network driver to allow AX.25 over Ethernet
 *	using G8BPQ encapsulation. It has been extracted from the protocol
 *	implementation because
 *
 *		- things got unreadable within the protocol stack
 *		- to cure the protocol stack from "feature-ism"
 *		- a protocol implementation shouldn't need to know on
 *		  which hardware it is running
 *		- user-level programs like the AX.25 utilities shouldn't
 *		  need to know about the hardware.
 *		- IP over ethernet encapsulated AX.25 was impossible
 *		- rxecho.c did not work
 *		- to have room for extensions
 *		- it just deserves to "live" as an own driver
 *
 *	This driver can use any ethernet destination address, and can be
 *	limited to accept frames from one dedicated ethernet card only.
 *
 *	Note that the driver sets up the BPQ devices automagically on
 *	startup or (if started before the "insmod" of an ethernet device)
 *	on "ifconfig up". It hopefully will remove the BPQ on "rmmod"ing
 *	the ethernet device (in fact: as soon as another ethernet or bpq
 *	device gets "ifconfig"ured).
 *
 *	I have heard that several people are thinking of experiments
 *	with highspeed packet radio using existing ethernet cards.
 *	Well, this driver is prepared for this purpose, just add
 *	your tx key control and a txdelay / tailtime algorithm,
 *	probably some buffering, and /voila/...
 *
 *	History
 *	BPQ   001	Joerg(DL1BKE)		Extracted BPQ code from AX.25
 *						protocol stack and added my own
 *						yet existing patches
 *	BPQ   002	Joerg(DL1BKE)		Scan network device list on
 *						startup.
 *	BPQ   003	Joerg(DL1BKE)		Ethernet destination address
 *						and accepted source address
 *						can be configured by an ioctl()
 *						call.
 *						Fixed to match Linux networking
 *						changes - 2.1.15.
 *	BPQ   004	Joerg(DL1BKE)		Fixed to not lock up on ifconfig.
 */

#include <linux/errno.h>
#include <linux/types.h>
#include <linux/socket.h>
#include <linux/in.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/net.h>
#include <net/ax25.h>
#include <linux/inet.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>
#include <linux/if_arp.h>
#include <linux/skbuff.h>
#include <net/sock.h>
#include <asm/system.h>
#include <asm/uaccess.h>
#include <linux/mm.h>
#include <linux/interrupt.h>
#include <linux/notifier.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/stat.h>
#include <linux/netfilter.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/rtnetlink.h>

#include <net/ip.h>
#include <net/arp.h>
#include <net/net_namespace.h>

#include <linux/bpqether.h>

static const char banner[] __initdata = KERN_INFO \
	"AX.25: bpqether driver version 004\n";

static char bcast_addr[6]={0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};

static char bpq_eth_addr[6];

static int bpq_rcv(struct sk_buff *, struct net_device *, struct packet_type *, struct net_device *);
static int bpq_device_event(struct notifier_block *, unsigned long, void *);

static struct packet_type bpq_packet_type __read_mostly = {
	.type	= cpu_to_be16(ETH_P_BPQ),
	.func	= bpq_rcv,
};

static struct notifier_block bpq_dev_notifier = {
	.notifier_call =bpq_device_event,
};


struct bpqdev {
	struct list_head bpq_list;	/* list of bpq devices chain */
	struct net_device *ethdev;	/* link to ethernet device */
	struct net_device *axdev;	/* bpq device (bpq#) */
	char   dest_addr[6];		/* ether destination address */
	char   acpt_addr[6];		/* accept ether frames from this address only */
};

static LIST_HEAD(bpq_devices);

/*
 * bpqether network devices are paired with ethernet devices below them, so
 * form a special "super class" of normal ethernet devices; split their locks
 * off into a separate class since they always nest.
 */
static struct lock_class_key bpq_netdev_xmit_lock_key;
static struct lock_class_key bpq_netdev_addr_lock_key;

static void bpq_set_lockdep_class_one(struct net_device *dev,
				      struct netdev_queue *txq,
				      void *_unused)
{
	lockdep_set_class(&txq->_xmit_lock, &bpq_netdev_xmit_lock_key);
}

static void bpq_set_lockdep_class(struct net_device *dev)
{
	lockdep_set_class(&dev->addr_list_lock, &bpq_netdev_addr_lock_key);
	netdev_for_each_tx_queue(dev, bpq_set_lockdep_class_one, NULL);
}

/* ------------------------------------------------------------------------ */


/*
 *	Get the ethernet device for a BPQ device
 */
static inline struct net_device *bpq_get_ether_dev(struct net_device *dev)
{
	struct bpqdev *bpq = netdev_priv(dev);

	return bpq ? bpq->ethdev : NULL;
}

/*
 *	Get the BPQ device for the ethernet device
 */
static inline struct net_device *bpq_get_ax25_dev(struct net_device *dev)
{
	struct bpqdev *bpq;

	list_for_each_entry_rcu(bpq, &bpq_devices, bpq_list) {
		if (bpq->ethdev == dev)
			return bpq->axdev;
	}
	return NULL;
}

static inline int dev_is_ethdev(struct net_device *dev)
{
	return (
			dev->type == ARPHRD_ETHER
			&& strncmp(dev->name, "dummy", 5)
	);
}

/* ------------------------------------------------------------------------ */


/*
 *	Receive an AX.25 frame via an ethernet interface.
 */
static int bpq_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *ptype, struct net_device *orig_dev)
{
	int len;
	char * ptr;
	struct ethhdr *eth;
	struct bpqdev *bpq;

	if (dev_net(dev) != &init_net)
		goto drop;

	if ((skb = skb_share_check(skb, GFP_ATOMIC)) == NULL)
		return NET_RX_DROP;

	if (!pskb_may_pull(skb, sizeof(struct ethhdr)))
		goto drop;

	rcu_read_lock();
	dev = bpq_get_ax25_dev(dev);

	if (dev == NULL || !netif_running(dev)) 
		goto drop_unlock;

	/*
	 * if we want to accept frames from just one ethernet device
	 * we check the source address of the sender.
	 */

	bpq = netdev_priv(dev);

	eth = eth_hdr(skb);

	if (!(bpq->acpt_addr[0] & 0x01) &&
	    memcmp(eth->h_source, bpq->acpt_addr, ETH_ALEN))
		goto drop_unlock;

	if (skb_cow(skb, sizeof(struct ethhdr)))
		goto drop_unlock;

	len = skb->data[0] + skb->data[1] * 256 - 5;

	skb_pull(skb, 2);	/* Remove the length bytes */
	skb_trim(skb, len);	/* Set the length of the data */

	dev->stats.rx_packets++;
	dev->stats.rx_bytes += len;

	ptr = skb_push(skb, 1);
	*ptr = 0;

	skb->protocol = ax25_type_trans(skb, dev);
	netif_rx(skb);
unlock:

	rcu_read_unlock();

	return 0;
drop_unlock:
	kfree_skb(skb);
	goto unlock;

drop:
	kfree_skb(skb);
	return 0;
}

/*
 * 	Send an AX.25 frame via an ethernet interface
 */
static netdev_tx_t bpq_xmit(struct sk_buff *skb, struct net_device *dev)
{
	unsigned char *ptr;
	struct bpqdev *bpq;
	int size;

	/*
	 * Just to be *really* sure not to send anything if the interface
	 * is down, the ethernet device may have gone.
	 */
	if (!netif_running(dev)) {
		kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	skb_pull(skb, 1);			/* Drop KISS byte */
	size = skb->len;

	/*
	 * We're about to mess with the skb which may still shared with the
	 * generic networking code so unshare and ensure it's got enough
	 * space for the BPQ headers.
	 */
	if (skb_cow(skb, AX25_BPQ_HEADER_LEN)) {
		if (net_ratelimit())
			pr_err("bpqether: out of memory\n");
		kfree_skb(skb);

		return NETDEV_TX_OK;
	}

	ptr = skb_push(skb, 2);			/* Make space for length */

	*ptr++ = (size + 5) % 256;
	*ptr++ = (size + 5) / 256;

	bpq = netdev_priv(dev);

	if ((dev = bpq_get_ether_dev(dev)) == NULL) {
		dev->stats.tx_dropped++;
		kfree_skb(skb);
		return NETDEV_TX_OK;
	}

	skb->protocol = ax25_type_trans(skb, dev);
	skb_reset_network_header(skb);
	dev_hard_header(skb, dev, ETH_P_BPQ, bpq->dest_addr, NULL, 0);
	dev->stats.tx_packets++;
	dev->stats.tx_bytes+=skb->len;
  
	dev_queue_xmit(skb);
	netif_wake_queue(dev);
	return NETDEV_TX_OK;
}

/*
 *	Set AX.25 callsign
 */
static int bpq_set_mac_address(struct net_device *dev, void *addr)
{
    struct sockaddr *sa = (struct sockaddr *)addr;

    memcpy(dev->dev_addr, sa->sa_data, dev->addr_len);

    return 0;
}

/*	Ioctl commands
 *
 *		SIOCSBPQETHOPT		reserved for enhancements
 *		SIOCSBPQETHADDR		set the destination and accepted
 *					source ethernet address (broadcast
 *					or multicast: accept all)
 */
static int bpq_ioctl(struct net_device *dev, struct ifreq *ifr, int cmd)
{
	struct bpq_ethaddr __user *ethaddr = ifr->ifr_data;
	struct bpqdev *bpq = netdev_priv(dev);
	struct bpq_req req;

	if (!capable(CAP_NET_ADMIN))
		return -EPERM;

	switch (cmd) {
		case SIOCSBPQETHOPT:
			if (copy_from_user(&req, ifr->ifr_data, sizeof(struct bpq_req)))
				return -EFAULT;
			switch (req.cmd) {
				case SIOCGBPQETHPARAM:
				case SIOCSBPQETHPARAM:
				default:
					return -EINVAL;
			}

			break;

		case SIOCSBPQETHADDR:
			if (copy_from_user(bpq->dest_addr, ethaddr->destination, ETH_ALEN))
				return -EFAULT;
			if (copy_from_user(bpq->acpt_addr, ethaddr->accept, ETH_ALEN))
				return -EFAULT;
			break;

		default:
			return -EINVAL;
	}

	return 0;
}

/*
 * open/close a device
 */
static int bpq_open(struct net_device *dev)
{
	netif_start_queue(dev);
	return 0;
}

static int bpq_close(struct net_device *dev)
{
	netif_stop_queue(dev);
	return 0;
}


/* ------------------------------------------------------------------------ */


/*
 *	Proc filesystem
 */
static void *bpq_seq_start(struct seq_file *seq, loff_t *pos)
	__acquires(RCU)
{
	int i = 1;
	struct bpqdev *bpqdev;

	rcu_read_lock();

	if (*pos == 0)
		return SEQ_START_TOKEN;
	
	list_for_each_entry_rcu(bpqdev, &bpq_devices, bpq_list) {
		if (i == *pos)
			return bpqdev;
	}
	return NULL;
}

static void *bpq_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
	struct list_head *p;

	++*pos;

	if (v == SEQ_START_TOKEN)
		p = rcu_dereference(bpq_devices.next);
	else
		p = rcu_dereference(((struct bpqdev *)v)->bpq_list.next);

	return (p == &bpq_devices) ? NULL 
		: list_entry(p, struct bpqdev, bpq_list);
}

static void bpq_seq_stop(struct seq_file *seq, void *v)
	__releases(RCU)
{
	rcu_read_unlock();
}


static int bpq_seq_show(struct seq_file *seq, void *v)
{
	if (v == SEQ_START_TOKEN)
		seq_puts(seq, 
			 "dev   ether      destination        accept from\n");
	else {
		const struct bpqdev *bpqdev = v;

		seq_printf(seq, "%-5s %-10s %pM  ",
			bpqdev->axdev->name, bpqdev->ethdev->name,
			bpqdev->dest_addr);

		if (is_multicast_ether_addr(bpqdev->acpt_addr))
			seq_printf(seq, "*\n");
		else
			seq_printf(seq, "%pM\n", bpqdev->acpt_addr);

	}
	return 0;
}

static const struct seq_operations bpq_seqops = {
	.start = bpq_seq_start,
	.next = bpq_seq_next,
	.stop = bpq_seq_stop,
	.show = bpq_seq_show,
};

static int bpq_info_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &bpq_seqops);
}

static const struct file_operations bpq_info_fops = {
	.owner = THIS_MODULE,
	.open = bpq_info_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release,
};


/* ------------------------------------------------------------------------ */

static const struct net_device_ops bpq_netdev_ops = {
	.ndo_open	     = bpq_open,
	.ndo_stop	     = bpq_close,
	.ndo_start_xmit	     = bpq_xmit,
	.ndo_set_mac_address = bpq_set_mac_address,
	.ndo_do_ioctl	     = bpq_ioctl,
};

static void bpq_setup(struct net_device *dev)
{
	dev->netdev_ops	     = &bpq_netdev_ops;
	dev->destructor	     = free_netdev;

	memcpy(dev->broadcast, &ax25_bcast, AX25_ADDR_LEN);
	memcpy(dev->dev_addr,  &ax25_defaddr, AX25_ADDR_LEN);

	dev->flags      = 0;

#if defined(CONFIG_AX25) || defined(CONFIG_AX25_MODULE)
	dev->header_ops      = &ax25_header_ops;
#endif

	dev->type            = ARPHRD_AX25;
	dev->hard_header_len = AX25_MAX_HEADER_LEN + AX25_BPQ_HEADER_LEN;
	dev->mtu             = AX25_DEF_PACLEN;
	dev->addr_len        = AX25_ADDR_LEN;

}

/*
 *	Setup a new device.
 */
static int bpq_new_device(struct net_device *edev)
{
	int err;
	struct net_device *ndev;
	struct bpqdev *bpq;

	ndev = alloc_netdev(sizeof(struct bpqdev), "bpq%d",
			   bpq_setup);
	if (!ndev)
		return -ENOMEM;

		
	bpq = netdev_priv(ndev);
	dev_hold(edev);
	bpq->ethdev = edev;
	bpq->axdev = ndev;

	memcpy(bpq->dest_addr, bcast_addr, sizeof(bpq_eth_addr));
	memcpy(bpq->acpt_addr, bcast_addr, sizeof(bpq_eth_addr));

	err = dev_alloc_name(ndev, ndev->name);
	if (err < 0) 
		goto error;

	err = register_netdevice(ndev);
	if (err)
		goto error;
	bpq_set_lockdep_class(ndev);

	/* List protected by RTNL */
	list_add_rcu(&bpq->bpq_list, &bpq_devices);
	return 0;

 error:
	dev_put(edev);
	free_netdev(ndev);
	return err;
	
}

static void bpq_free_device(struct net_device *ndev)
{
	struct bpqdev *bpq = netdev_priv(ndev);

	dev_put(bpq->ethdev);
	list_del_rcu(&bpq->bpq_list);

	unregister_netdevice(ndev);
}

/*
 *	Handle device status changes.
 */
static int bpq_device_event(struct notifier_block *this,unsigned long event, void *ptr)
{
	struct net_device *dev = (struct net_device *)ptr;

	if (dev_net(dev) != &init_net)
		return NOTIFY_DONE;

	if (!dev_is_ethdev(dev))
		return NOTIFY_DONE;

	switch (event) {
	case NETDEV_UP:		/* new ethernet device -> new BPQ interface */
		if (bpq_get_ax25_dev(dev) == NULL)
			bpq_new_device(dev);
		break;

	case NETDEV_DOWN:	/* ethernet device closed -> close BPQ interface */
		if ((dev = bpq_get_ax25_dev(dev)) != NULL)
			dev_close(dev);
		break;

	case NETDEV_UNREGISTER:	/* ethernet device removed -> free BPQ interface */
		if ((dev = bpq_get_ax25_dev(dev)) != NULL)
			bpq_free_device(dev);
		break;
	default:
		break;
	}

	return NOTIFY_DONE;
}


/* ------------------------------------------------------------------------ */

/*
 * Initialize driver. To be called from af_ax25 if not compiled as a
 * module
 */
static int __init bpq_init_driver(void)
{
#ifdef CONFIG_PROC_FS
	if (!proc_net_fops_create(&init_net, "bpqether", S_IRUGO, &bpq_info_fops)) {
		printk(KERN_ERR
			"bpq: cannot create /proc/net/bpqether entry.\n");
		return -ENOENT;
	}
#endif  /* CONFIG_PROC_FS */

	dev_add_pack(&bpq_packet_type);

	register_netdevice_notifier(&bpq_dev_notifier);

	printk(banner);

	return 0;
}

static void __exit bpq_cleanup_driver(void)
{
	struct bpqdev *bpq;

	dev_remove_pack(&bpq_packet_type);

	unregister_netdevice_notifier(&bpq_dev_notifier);

	proc_net_remove(&init_net, "bpqether");

	rtnl_lock();
	while (!list_empty(&bpq_devices)) {
		bpq = list_entry(bpq_devices.next, struct bpqdev, bpq_list);
		bpq_free_device(bpq->axdev);
	}
	rtnl_unlock();
}

MODULE_AUTHOR("Joerg Reuter DL1BKE <jreuter@yaina.de>");
MODULE_DESCRIPTION("Transmit and receive AX.25 packets over Ethernet");
MODULE_LICENSE("GPL");
module_init(bpq_init_driver);
module_exit(bpq_cleanup_driver);