aboutsummaryrefslogtreecommitdiff
path: root/net/atm/br2684.c
blob: 13858e2675c5f57277f031eacece09724bc84cd3 (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
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
/*
 * Ethernet netdevice using ATM AAL5 as underlying carrier
 * (RFC1483 obsoleted by RFC2684) for Linux
 *
 * Authors: Marcell GAL, 2000, XDSL Ltd, Hungary
 *          Eric Kinzie, 2006-2007, US Naval Research Laboratory
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/netdevice.h>
#include <linux/skbuff.h>
#include <linux/etherdevice.h>
#include <linux/rtnetlink.h>
#include <linux/ip.h>
#include <asm/uaccess.h>
#include <net/arp.h>
#include <linux/atm.h>
#include <linux/atmdev.h>
#include <linux/capability.h>
#include <linux/seq_file.h>

#include <linux/atmbr2684.h>

#include "common.h"

#ifdef SKB_DEBUG
static void skb_debug(const struct sk_buff *skb)
{
#define NUM2PRINT 50
	char buf[NUM2PRINT * 3 + 1];	/* 3 chars per byte */
	int i = 0;
	for (i = 0; i < skb->len && i < NUM2PRINT; i++) {
		sprintf(buf + i * 3, "%2.2x ", 0xff & skb->data[i]);
	}
	printk(KERN_DEBUG "br2684: skb: %s\n", buf);
}
#else
#define skb_debug(skb)	do {} while (0)
#endif

#define BR2684_ETHERTYPE_LEN	2
#define BR2684_PAD_LEN		2

#define LLC		0xaa, 0xaa, 0x03
#define SNAP_BRIDGED	0x00, 0x80, 0xc2
#define SNAP_ROUTED	0x00, 0x00, 0x00
#define PID_ETHERNET	0x00, 0x07
#define ETHERTYPE_IPV4	0x08, 0x00
#define ETHERTYPE_IPV6	0x86, 0xdd
#define PAD_BRIDGED	0x00, 0x00

static unsigned char ethertype_ipv4[] = { ETHERTYPE_IPV4 };
static unsigned char ethertype_ipv6[] = { ETHERTYPE_IPV6 };
static unsigned char llc_oui_pid_pad[] =
			{ LLC, SNAP_BRIDGED, PID_ETHERNET, PAD_BRIDGED };
static unsigned char llc_oui_ipv4[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV4 };
static unsigned char llc_oui_ipv6[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV6 };

enum br2684_encaps {
	e_vc = BR2684_ENCAPS_VC,
	e_llc = BR2684_ENCAPS_LLC,
};

struct br2684_vcc {
	struct atm_vcc *atmvcc;
	struct net_device *device;
	/* keep old push, pop functions for chaining */
	void (*old_push) (struct atm_vcc * vcc, struct sk_buff * skb);
	/* void (*old_pop)(struct atm_vcc *vcc, struct sk_buff *skb); */
	enum br2684_encaps encaps;
	struct list_head brvccs;
#ifdef CONFIG_ATM_BR2684_IPFILTER
	struct br2684_filter filter;
#endif /* CONFIG_ATM_BR2684_IPFILTER */
	unsigned copies_needed, copies_failed;
};

struct br2684_dev {
	struct net_device *net_dev;
	struct list_head br2684_devs;
	int number;
	struct list_head brvccs;	/* one device <=> one vcc (before xmas) */
	struct net_device_stats stats;
	int mac_was_set;
	enum br2684_payload payload;
};

/*
 * This lock should be held for writing any time the list of devices or
 * their attached vcc's could be altered.  It should be held for reading
 * any time these are being queried.  Note that we sometimes need to
 * do read-locking under interrupt context, so write locking must block
 * the current CPU's interrupts
 */
static DEFINE_RWLOCK(devs_lock);

static LIST_HEAD(br2684_devs);

static inline struct br2684_dev *BRPRIV(const struct net_device *net_dev)
{
	return (struct br2684_dev *)net_dev->priv;
}

static inline struct net_device *list_entry_brdev(const struct list_head *le)
{
	return list_entry(le, struct br2684_dev, br2684_devs)->net_dev;
}

static inline struct br2684_vcc *BR2684_VCC(const struct atm_vcc *atmvcc)
{
	return (struct br2684_vcc *)(atmvcc->user_back);
}

static inline struct br2684_vcc *list_entry_brvcc(const struct list_head *le)
{
	return list_entry(le, struct br2684_vcc, brvccs);
}

/* Caller should hold read_lock(&devs_lock) */
static struct net_device *br2684_find_dev(const struct br2684_if_spec *s)
{
	struct list_head *lh;
	struct net_device *net_dev;
	switch (s->method) {
	case BR2684_FIND_BYNUM:
		list_for_each(lh, &br2684_devs) {
			net_dev = list_entry_brdev(lh);
			if (BRPRIV(net_dev)->number == s->spec.devnum)
				return net_dev;
		}
		break;
	case BR2684_FIND_BYIFNAME:
		list_for_each(lh, &br2684_devs) {
			net_dev = list_entry_brdev(lh);
			if (!strncmp(net_dev->name, s->spec.ifname, IFNAMSIZ))
				return net_dev;
		}
		break;
	}
	return NULL;
}

/*
 * Send a packet out a particular vcc.  Not to useful right now, but paves
 * the way for multiple vcc's per itf.  Returns true if we can send,
 * otherwise false
 */
static int br2684_xmit_vcc(struct sk_buff *skb, struct br2684_dev *brdev,
			   struct br2684_vcc *brvcc)
{
	struct atm_vcc *atmvcc;
	int minheadroom = (brvcc->encaps == e_llc) ? 10 : 2;

	if (skb_headroom(skb) < minheadroom) {
		struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
		brvcc->copies_needed++;
		dev_kfree_skb(skb);
		if (skb2 == NULL) {
			brvcc->copies_failed++;
			return 0;
		}
		skb = skb2;
	}

	if (brvcc->encaps == e_llc) {
		if (brdev->payload == p_bridged) {
			skb_push(skb, sizeof(llc_oui_pid_pad));
			skb_copy_to_linear_data(skb, llc_oui_pid_pad,
						sizeof(llc_oui_pid_pad));
		} else if (brdev->payload == p_routed) {
			unsigned short prot = ntohs(skb->protocol);

			skb_push(skb, sizeof(llc_oui_ipv4));
			switch (prot) {
			case ETH_P_IP:
				skb_copy_to_linear_data(skb, llc_oui_ipv4,
							sizeof(llc_oui_ipv4));
				break;
			case ETH_P_IPV6:
				skb_copy_to_linear_data(skb, llc_oui_ipv6,
							sizeof(llc_oui_ipv6));
				break;
			default:
				dev_kfree_skb(skb);
				return 0;
			}
		}
	} else {
		skb_push(skb, 2);
		if (brdev->payload == p_bridged)
			memset(skb->data, 0, 2);
	}
	skb_debug(skb);

	ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
	if (!atm_may_send(atmvcc, skb->truesize)) {
		/*
		 * We free this here for now, because we cannot know in a higher
		 * layer whether the skb pointer it supplied wasn't freed yet.
		 * Now, it always is.
		 */
		dev_kfree_skb(skb);
		return 0;
	}
	atomic_add(skb->truesize, &sk_atm(atmvcc)->sk_wmem_alloc);
	ATM_SKB(skb)->atm_options = atmvcc->atm_options;
	brdev->stats.tx_packets++;
	brdev->stats.tx_bytes += skb->len;
	atmvcc->send(atmvcc, skb);
	return 1;
}

static inline struct br2684_vcc *pick_outgoing_vcc(struct sk_buff *skb,
						   struct br2684_dev *brdev)
{
	return list_empty(&brdev->brvccs) ? NULL : list_entry_brvcc(brdev->brvccs.next);	/* 1 vcc/dev right now */
}

static int br2684_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
	struct br2684_dev *brdev = BRPRIV(dev);
	struct br2684_vcc *brvcc;

	pr_debug("br2684_start_xmit, skb->dst=%p\n", skb->dst);
	read_lock(&devs_lock);
	brvcc = pick_outgoing_vcc(skb, brdev);
	if (brvcc == NULL) {
		pr_debug("no vcc attached to dev %s\n", dev->name);
		brdev->stats.tx_errors++;
		brdev->stats.tx_carrier_errors++;
		/* netif_stop_queue(dev); */
		dev_kfree_skb(skb);
		read_unlock(&devs_lock);
		return 0;
	}
	if (!br2684_xmit_vcc(skb, brdev, brvcc)) {
		/*
		 * We should probably use netif_*_queue() here, but that
		 * involves added complication.  We need to walk before
		 * we can run.
		 *
		 * Don't free here! this pointer might be no longer valid!
		 */
		brdev->stats.tx_errors++;
		brdev->stats.tx_fifo_errors++;
	}
	read_unlock(&devs_lock);
	return 0;
}

static struct net_device_stats *br2684_get_stats(struct net_device *dev)
{
	pr_debug("br2684_get_stats\n");
	return &BRPRIV(dev)->stats;
}

/*
 * We remember when the MAC gets set, so we don't override it later with
 * the ESI of the ATM card of the first VC
 */
static int (*my_eth_mac_addr) (struct net_device *, void *);
static int br2684_mac_addr(struct net_device *dev, void *p)
{
	int err = my_eth_mac_addr(dev, p);
	if (!err)
		BRPRIV(dev)->mac_was_set = 1;
	return err;
}

#ifdef CONFIG_ATM_BR2684_IPFILTER
/* this IOCTL is experimental. */
static int br2684_setfilt(struct atm_vcc *atmvcc, void __user * arg)
{
	struct br2684_vcc *brvcc;
	struct br2684_filter_set fs;

	if (copy_from_user(&fs, arg, sizeof fs))
		return -EFAULT;
	if (fs.ifspec.method != BR2684_FIND_BYNOTHING) {
		/*
		 * This is really a per-vcc thing, but we can also search
		 * by device.
		 */
		struct br2684_dev *brdev;
		read_lock(&devs_lock);
		brdev = BRPRIV(br2684_find_dev(&fs.ifspec));
		if (brdev == NULL || list_empty(&brdev->brvccs) || brdev->brvccs.next != brdev->brvccs.prev)	/* >1 VCC */
			brvcc = NULL;
		else
			brvcc = list_entry_brvcc(brdev->brvccs.next);
		read_unlock(&devs_lock);
		if (brvcc == NULL)
			return -ESRCH;
	} else
		brvcc = BR2684_VCC(atmvcc);
	memcpy(&brvcc->filter, &fs.filter, sizeof(brvcc->filter));
	return 0;
}

/* Returns 1 if packet should be dropped */
static inline int
packet_fails_filter(__be16 type, struct br2684_vcc *brvcc, struct sk_buff *skb)
{
	if (brvcc->filter.netmask == 0)
		return 0;	/* no filter in place */
	if (type == htons(ETH_P_IP) &&
	    (((struct iphdr *)(skb->data))->daddr & brvcc->filter.
	     netmask) == brvcc->filter.prefix)
		return 0;
	if (type == htons(ETH_P_ARP))
		return 0;
	/*
	 * TODO: we should probably filter ARPs too.. don't want to have
	 * them returning values that don't make sense, or is that ok?
	 */
	return 1;		/* drop */
}
#endif /* CONFIG_ATM_BR2684_IPFILTER */

static void br2684_close_vcc(struct br2684_vcc *brvcc)
{
	pr_debug("removing VCC %p from dev %p\n", brvcc, brvcc->device);
	write_lock_irq(&devs_lock);
	list_del(&brvcc->brvccs);
	write_unlock_irq(&devs_lock);
	brvcc->atmvcc->user_back = NULL;	/* what about vcc->recvq ??? */
	brvcc->old_push(brvcc->atmvcc, NULL);	/* pass on the bad news */
	kfree(brvcc);
	module_put(THIS_MODULE);
}

/* when AAL5 PDU comes in: */
static void br2684_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
{
	struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
	struct net_device *net_dev = brvcc->device;
	struct br2684_dev *brdev = BRPRIV(net_dev);

	pr_debug("br2684_push\n");

	if (unlikely(skb == NULL)) {
		/* skb==NULL means VCC is being destroyed */
		br2684_close_vcc(brvcc);
		if (list_empty(&brdev->brvccs)) {
			write_lock_irq(&devs_lock);
			list_del(&brdev->br2684_devs);
			write_unlock_irq(&devs_lock);
			unregister_netdev(net_dev);
		}
		return;
	}

	skb_debug(skb);
	atm_return(atmvcc, skb->truesize);
	pr_debug("skb from brdev %p\n", brdev);
	if (brvcc->encaps == e_llc) {

		if (skb->len > 7 && skb->data[7] == 0x01)
			__skb_trim(skb, skb->len - 4);

		/* accept packets that have "ipv[46]" in the snap header */
		if ((skb->len >= (sizeof(llc_oui_ipv4)))
		    &&
		    (memcmp
		     (skb->data, llc_oui_ipv4,
		      sizeof(llc_oui_ipv4) - BR2684_ETHERTYPE_LEN) == 0)) {
			if (memcmp
			    (skb->data + 6, ethertype_ipv6,
			     sizeof(ethertype_ipv6)) == 0)
				skb->protocol = __constant_htons(ETH_P_IPV6);
			else if (memcmp
				 (skb->data + 6, ethertype_ipv4,
				  sizeof(ethertype_ipv4)) == 0)
				skb->protocol = __constant_htons(ETH_P_IP);
			else {
				brdev->stats.rx_errors++;
				dev_kfree_skb(skb);
				return;
			}
			skb_pull(skb, sizeof(llc_oui_ipv4));
			skb_reset_network_header(skb);
			skb->pkt_type = PACKET_HOST;
			/*
			 * Let us waste some time for checking the encapsulation.
			 * Note, that only 7 char is checked so frames with a valid FCS
			 * are also accepted (but FCS is not checked of course).
			 */
		} else if ((skb->len >= sizeof(llc_oui_pid_pad)) &&
			   (memcmp(skb->data, llc_oui_pid_pad, 7) == 0)) {
			skb_pull(skb, sizeof(llc_oui_pid_pad));
			skb->protocol = eth_type_trans(skb, net_dev);
		} else {
			brdev->stats.rx_errors++;
			dev_kfree_skb(skb);
			return;
		}

	} else {
		/* first 2 chars should be 0 */
		if (*((u16 *) (skb->data)) != 0) {
			brdev->stats.rx_errors++;
			dev_kfree_skb(skb);
			return;
		}
		skb_pull(skb, BR2684_PAD_LEN + ETH_HLEN);	/* pad, dstmac, srcmac, ethtype */
		skb->protocol = eth_type_trans(skb, net_dev);
	}

#ifdef CONFIG_ATM_BR2684_IPFILTER
	if (unlikely(packet_fails_filter(skb->protocol, brvcc, skb))) {
		brdev->stats.rx_dropped++;
		dev_kfree_skb(skb);
		return;
	}
#endif /* CONFIG_ATM_BR2684_IPFILTER */
	skb->dev = net_dev;
	ATM_SKB(skb)->vcc = atmvcc;	/* needed ? */
	pr_debug("received packet's protocol: %x\n", ntohs(skb->protocol));
	skb_debug(skb);
	if (unlikely(!(net_dev->flags & IFF_UP))) {
		/* sigh, interface is down */
		brdev->stats.rx_dropped++;
		dev_kfree_skb(skb);
		return;
	}
	brdev->stats.rx_packets++;
	brdev->stats.rx_bytes += skb->len;
	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
	netif_rx(skb);
}

/*
 * Assign a vcc to a dev
 * Note: we do not have explicit unassign, but look at _push()
 */
static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
{
	int err;
	struct br2684_vcc *brvcc;
	struct sk_buff *skb;
	struct sk_buff_head *rq;
	struct br2684_dev *brdev;
	struct net_device *net_dev;
	struct atm_backend_br2684 be;
	unsigned long flags;

	if (copy_from_user(&be, arg, sizeof be))
		return -EFAULT;
	brvcc = kzalloc(sizeof(struct br2684_vcc), GFP_KERNEL);
	if (!brvcc)
		return -ENOMEM;
	write_lock_irq(&devs_lock);
	net_dev = br2684_find_dev(&be.ifspec);
	if (net_dev == NULL) {
		printk(KERN_ERR
		       "br2684: tried to attach to non-existant device\n");
		err = -ENXIO;
		goto error;
	}
	brdev = BRPRIV(net_dev);
	if (atmvcc->push == NULL) {
		err = -EBADFD;
		goto error;
	}
	if (!list_empty(&brdev->brvccs)) {
		/* Only 1 VCC/dev right now */
		err = -EEXIST;
		goto error;
	}
	if (be.fcs_in != BR2684_FCSIN_NO || be.fcs_out != BR2684_FCSOUT_NO ||
	    be.fcs_auto || be.has_vpiid || be.send_padding || (be.encaps !=
							       BR2684_ENCAPS_VC
							       && be.encaps !=
							       BR2684_ENCAPS_LLC)
	    || be.min_size != 0) {
		err = -EINVAL;
		goto error;
	}
	pr_debug("br2684_regvcc vcc=%p, encaps=%d, brvcc=%p\n", atmvcc,
		 be.encaps, brvcc);
	if (list_empty(&brdev->brvccs) && !brdev->mac_was_set) {
		unsigned char *esi = atmvcc->dev->esi;
		if (esi[0] | esi[1] | esi[2] | esi[3] | esi[4] | esi[5])
			memcpy(net_dev->dev_addr, esi, net_dev->addr_len);
		else
			net_dev->dev_addr[2] = 1;
	}
	list_add(&brvcc->brvccs, &brdev->brvccs);
	write_unlock_irq(&devs_lock);
	brvcc->device = net_dev;
	brvcc->atmvcc = atmvcc;
	atmvcc->user_back = brvcc;
	brvcc->encaps = (enum br2684_encaps)be.encaps;
	brvcc->old_push = atmvcc->push;
	barrier();
	atmvcc->push = br2684_push;

	rq = &sk_atm(atmvcc)->sk_receive_queue;

	spin_lock_irqsave(&rq->lock, flags);
	if (skb_queue_empty(rq)) {
		skb = NULL;
	} else {
		/* NULL terminate the list.  */
		rq->prev->next = NULL;
		skb = rq->next;
	}
	rq->prev = rq->next = (struct sk_buff *)rq;
	rq->qlen = 0;
	spin_unlock_irqrestore(&rq->lock, flags);

	while (skb) {
		struct sk_buff *next = skb->next;

		skb->next = skb->prev = NULL;
		BRPRIV(skb->dev)->stats.rx_bytes -= skb->len;
		BRPRIV(skb->dev)->stats.rx_packets--;
		br2684_push(atmvcc, skb);

		skb = next;
	}
	__module_get(THIS_MODULE);
	return 0;
      error:
	write_unlock_irq(&devs_lock);
	kfree(brvcc);
	return err;
}

static void br2684_setup(struct net_device *netdev)
{
	struct br2684_dev *brdev = BRPRIV(netdev);

	ether_setup(netdev);
	brdev->net_dev = netdev;

	my_eth_mac_addr = netdev->set_mac_address;
	netdev->set_mac_address = br2684_mac_addr;
	netdev->hard_start_xmit = br2684_start_xmit;
	netdev->get_stats = br2684_get_stats;

	INIT_LIST_HEAD(&brdev->brvccs);
}

static void br2684_setup_routed(struct net_device *netdev)
{
	struct br2684_dev *brdev = BRPRIV(netdev);
	brdev->net_dev = netdev;

	netdev->hard_header_len = 0;
	my_eth_mac_addr = netdev->set_mac_address;
	netdev->set_mac_address = br2684_mac_addr;
	netdev->hard_start_xmit = br2684_start_xmit;
	netdev->get_stats = br2684_get_stats;
	netdev->addr_len = 0;
	netdev->mtu = 1500;
	netdev->type = ARPHRD_PPP;
	netdev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
	netdev->tx_queue_len = 100;
	INIT_LIST_HEAD(&brdev->brvccs);
}

static int br2684_create(void __user * arg)
{
	int err;
	struct net_device *netdev;
	struct br2684_dev *brdev;
	struct atm_newif_br2684 ni;
	enum br2684_payload payload;

	pr_debug("br2684_create\n");

	if (copy_from_user(&ni, arg, sizeof ni)) {
		return -EFAULT;
	}

	if (ni.media & BR2684_FLAG_ROUTED)
		payload = p_routed;
	else
		payload = p_bridged;
	ni.media &= 0xffff;	/* strip flags */

	if (ni.media != BR2684_MEDIA_ETHERNET || ni.mtu != 1500) {
		return -EINVAL;
	}

	netdev = alloc_netdev(sizeof(struct br2684_dev),
			      ni.ifname[0] ? ni.ifname : "nas%d",
			      (payload == p_routed) ?
			      br2684_setup_routed : br2684_setup);
	if (!netdev)
		return -ENOMEM;

	brdev = BRPRIV(netdev);

	pr_debug("registered netdev %s\n", netdev->name);
	/* open, stop, do_ioctl ? */
	err = register_netdev(netdev);
	if (err < 0) {
		printk(KERN_ERR "br2684_create: register_netdev failed\n");
		free_netdev(netdev);
		return err;
	}

	write_lock_irq(&devs_lock);
	brdev->payload = payload;
	brdev->number = list_empty(&br2684_devs) ? 1 :
	    BRPRIV(list_entry_brdev(br2684_devs.prev))->number + 1;
	list_add_tail(&brdev->br2684_devs, &br2684_devs);
	write_unlock_irq(&devs_lock);
	return 0;
}

/*
 * This handles ioctls actually performed on our vcc - we must return
 * -ENOIOCTLCMD for any unrecognized ioctl
 */
static int br2684_ioctl(struct socket *sock, unsigned int cmd,
			unsigned long arg)
{
	struct atm_vcc *atmvcc = ATM_SD(sock);
	void __user *argp = (void __user *)arg;
	atm_backend_t b;

	int err;
	switch (cmd) {
	case ATM_SETBACKEND:
	case ATM_NEWBACKENDIF:
		err = get_user(b, (atm_backend_t __user *) argp);
		if (err)
			return -EFAULT;
		if (b != ATM_BACKEND_BR2684)
			return -ENOIOCTLCMD;
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		if (cmd == ATM_SETBACKEND)
			return br2684_regvcc(atmvcc, argp);
		else
			return br2684_create(argp);
#ifdef CONFIG_ATM_BR2684_IPFILTER
	case BR2684_SETFILT:
		if (atmvcc->push != br2684_push)
			return -ENOIOCTLCMD;
		if (!capable(CAP_NET_ADMIN))
			return -EPERM;
		err = br2684_setfilt(atmvcc, argp);

		return err;
#endif /* CONFIG_ATM_BR2684_IPFILTER */
	}
	return -ENOIOCTLCMD;
}

static struct atm_ioctl br2684_ioctl_ops = {
	.owner = THIS_MODULE,
	.ioctl = br2684_ioctl,
};

#ifdef CONFIG_PROC_FS
static void *br2684_seq_start(struct seq_file *seq, loff_t * pos)
	__acquires(devs_lock)
{
	read_lock(&devs_lock);
	return seq_list_start(&br2684_devs, *pos);
}

static void *br2684_seq_next(struct seq_file *seq, void *v, loff_t * pos)
{
	return seq_list_next(v, &br2684_devs, pos);
}

static void br2684_seq_stop(struct seq_file *seq, void *v)
	__releases(devs_lock)
{
	read_unlock(&devs_lock);
}

static int br2684_seq_show(struct seq_file *seq, void *v)
{
	const struct br2684_dev *brdev = list_entry(v, struct br2684_dev,
						    br2684_devs);
	const struct net_device *net_dev = brdev->net_dev;
	const struct br2684_vcc *brvcc;
	DECLARE_MAC_BUF(mac);

	seq_printf(seq, "dev %.16s: num=%d, mac=%s (%s)\n",
		   net_dev->name,
		   brdev->number,
		   print_mac(mac, net_dev->dev_addr),
		   brdev->mac_was_set ? "set" : "auto");

	list_for_each_entry(brvcc, &brdev->brvccs, brvccs) {
		seq_printf(seq, "  vcc %d.%d.%d: encaps=%s payload=%s"
			   ", failed copies %u/%u"
			   "\n", brvcc->atmvcc->dev->number,
			   brvcc->atmvcc->vpi, brvcc->atmvcc->vci,
			   (brvcc->encaps == e_llc) ? "LLC" : "VC",
			   (brdev->payload == p_bridged) ? "bridged" : "routed",
			   brvcc->copies_failed, brvcc->copies_needed);
#ifdef CONFIG_ATM_BR2684_IPFILTER
#define b1(var, byte)	((u8 *) &brvcc->filter.var)[byte]
#define bs(var)		b1(var, 0), b1(var, 1), b1(var, 2), b1(var, 3)
		if (brvcc->filter.netmask != 0)
			seq_printf(seq, "    filter=%d.%d.%d.%d/"
				   "%d.%d.%d.%d\n", bs(prefix), bs(netmask));
#undef bs
#undef b1
#endif /* CONFIG_ATM_BR2684_IPFILTER */
	}
	return 0;
}

static const struct seq_operations br2684_seq_ops = {
	.start = br2684_seq_start,
	.next = br2684_seq_next,
	.stop = br2684_seq_stop,
	.show = br2684_seq_show,
};

static int br2684_proc_open(struct inode *inode, struct file *file)
{
	return seq_open(file, &br2684_seq_ops);
}

static const struct file_operations br2684_proc_ops = {
	.owner = THIS_MODULE,
	.open = br2684_proc_open,
	.read = seq_read,
	.llseek = seq_lseek,
	.release = seq_release,
};

extern struct proc_dir_entry *atm_proc_root;	/* from proc.c */
#endif /* CONFIG_PROC_FS */

static int __init br2684_init(void)
{
#ifdef CONFIG_PROC_FS
	struct proc_dir_entry *p;
	p = proc_create("br2684", 0, atm_proc_root, &br2684_proc_ops);
	if (p == NULL)
		return -ENOMEM;
#endif
	register_atm_ioctl(&br2684_ioctl_ops);
	return 0;
}

static void __exit br2684_exit(void)
{
	struct net_device *net_dev;
	struct br2684_dev *brdev;
	struct br2684_vcc *brvcc;
	deregister_atm_ioctl(&br2684_ioctl_ops);

#ifdef CONFIG_PROC_FS
	remove_proc_entry("br2684", atm_proc_root);
#endif

	while (!list_empty(&br2684_devs)) {
		net_dev = list_entry_brdev(br2684_devs.next);
		brdev = BRPRIV(net_dev);
		while (!list_empty(&brdev->brvccs)) {
			brvcc = list_entry_brvcc(brdev->brvccs.next);
			br2684_close_vcc(brvcc);
		}

		list_del(&brdev->br2684_devs);
		unregister_netdev(net_dev);
	}
}

module_init(br2684_init);
module_exit(br2684_exit);

MODULE_AUTHOR("Marcell GAL");
MODULE_DESCRIPTION("RFC2684 bridged protocols over ATM/AAL5");
MODULE_LICENSE("GPL");