xref: /openbmc/linux/net/atm/br2684.c (revision 50dc9a85)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Ethernet netdevice using ATM AAL5 as underlying carrier
4  * (RFC1483 obsoleted by RFC2684) for Linux
5  *
6  * Authors: Marcell GAL, 2000, XDSL Ltd, Hungary
7  *          Eric Kinzie, 2006-2007, US Naval Research Laboratory
8  */
9 
10 #define pr_fmt(fmt) KBUILD_MODNAME ":%s: " fmt, __func__
11 
12 #include <linux/module.h>
13 #include <linux/init.h>
14 #include <linux/kernel.h>
15 #include <linux/list.h>
16 #include <linux/netdevice.h>
17 #include <linux/skbuff.h>
18 #include <linux/etherdevice.h>
19 #include <linux/rtnetlink.h>
20 #include <linux/ip.h>
21 #include <linux/uaccess.h>
22 #include <linux/slab.h>
23 #include <net/arp.h>
24 #include <linux/atm.h>
25 #include <linux/atmdev.h>
26 #include <linux/capability.h>
27 #include <linux/seq_file.h>
28 
29 #include <linux/atmbr2684.h>
30 
31 #include "common.h"
32 
33 static void skb_debug(const struct sk_buff *skb)
34 {
35 #ifdef SKB_DEBUG
36 #define NUM2PRINT 50
37 	print_hex_dump(KERN_DEBUG, "br2684: skb: ", DUMP_OFFSET,
38 		       16, 1, skb->data, min(NUM2PRINT, skb->len), true);
39 #endif
40 }
41 
42 #define BR2684_ETHERTYPE_LEN	2
43 #define BR2684_PAD_LEN		2
44 
45 #define LLC		0xaa, 0xaa, 0x03
46 #define SNAP_BRIDGED	0x00, 0x80, 0xc2
47 #define SNAP_ROUTED	0x00, 0x00, 0x00
48 #define PID_ETHERNET	0x00, 0x07
49 #define ETHERTYPE_IPV4	0x08, 0x00
50 #define ETHERTYPE_IPV6	0x86, 0xdd
51 #define PAD_BRIDGED	0x00, 0x00
52 
53 static const unsigned char ethertype_ipv4[] = { ETHERTYPE_IPV4 };
54 static const unsigned char ethertype_ipv6[] = { ETHERTYPE_IPV6 };
55 static const unsigned char llc_oui_pid_pad[] =
56 			{ LLC, SNAP_BRIDGED, PID_ETHERNET, PAD_BRIDGED };
57 static const unsigned char pad[] = { PAD_BRIDGED };
58 static const unsigned char llc_oui_ipv4[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV4 };
59 static const unsigned char llc_oui_ipv6[] = { LLC, SNAP_ROUTED, ETHERTYPE_IPV6 };
60 
61 enum br2684_encaps {
62 	e_vc = BR2684_ENCAPS_VC,
63 	e_llc = BR2684_ENCAPS_LLC,
64 };
65 
66 struct br2684_vcc {
67 	struct atm_vcc *atmvcc;
68 	struct net_device *device;
69 	/* keep old push, pop functions for chaining */
70 	void (*old_push)(struct atm_vcc *vcc, struct sk_buff *skb);
71 	void (*old_pop)(struct atm_vcc *vcc, struct sk_buff *skb);
72 	void (*old_release_cb)(struct atm_vcc *vcc);
73 	struct module *old_owner;
74 	enum br2684_encaps encaps;
75 	struct list_head brvccs;
76 #ifdef CONFIG_ATM_BR2684_IPFILTER
77 	struct br2684_filter filter;
78 #endif /* CONFIG_ATM_BR2684_IPFILTER */
79 	unsigned int copies_needed, copies_failed;
80 	atomic_t qspace;
81 };
82 
83 struct br2684_dev {
84 	struct net_device *net_dev;
85 	struct list_head br2684_devs;
86 	int number;
87 	struct list_head brvccs;	/* one device <=> one vcc (before xmas) */
88 	int mac_was_set;
89 	enum br2684_payload payload;
90 };
91 
92 /*
93  * This lock should be held for writing any time the list of devices or
94  * their attached vcc's could be altered.  It should be held for reading
95  * any time these are being queried.  Note that we sometimes need to
96  * do read-locking under interrupting context, so write locking must block
97  * the current CPU's interrupts.
98  */
99 static DEFINE_RWLOCK(devs_lock);
100 
101 static LIST_HEAD(br2684_devs);
102 
103 static inline struct br2684_dev *BRPRIV(const struct net_device *net_dev)
104 {
105 	return netdev_priv(net_dev);
106 }
107 
108 static inline struct net_device *list_entry_brdev(const struct list_head *le)
109 {
110 	return list_entry(le, struct br2684_dev, br2684_devs)->net_dev;
111 }
112 
113 static inline struct br2684_vcc *BR2684_VCC(const struct atm_vcc *atmvcc)
114 {
115 	return (struct br2684_vcc *)(atmvcc->user_back);
116 }
117 
118 static inline struct br2684_vcc *list_entry_brvcc(const struct list_head *le)
119 {
120 	return list_entry(le, struct br2684_vcc, brvccs);
121 }
122 
123 /* Caller should hold read_lock(&devs_lock) */
124 static struct net_device *br2684_find_dev(const struct br2684_if_spec *s)
125 {
126 	struct list_head *lh;
127 	struct net_device *net_dev;
128 	switch (s->method) {
129 	case BR2684_FIND_BYNUM:
130 		list_for_each(lh, &br2684_devs) {
131 			net_dev = list_entry_brdev(lh);
132 			if (BRPRIV(net_dev)->number == s->spec.devnum)
133 				return net_dev;
134 		}
135 		break;
136 	case BR2684_FIND_BYIFNAME:
137 		list_for_each(lh, &br2684_devs) {
138 			net_dev = list_entry_brdev(lh);
139 			if (!strncmp(net_dev->name, s->spec.ifname, IFNAMSIZ))
140 				return net_dev;
141 		}
142 		break;
143 	}
144 	return NULL;
145 }
146 
147 static int atm_dev_event(struct notifier_block *this, unsigned long event,
148 		 void *arg)
149 {
150 	struct atm_dev *atm_dev = arg;
151 	struct list_head *lh;
152 	struct net_device *net_dev;
153 	struct br2684_vcc *brvcc;
154 	struct atm_vcc *atm_vcc;
155 	unsigned long flags;
156 
157 	pr_debug("event=%ld dev=%p\n", event, atm_dev);
158 
159 	read_lock_irqsave(&devs_lock, flags);
160 	list_for_each(lh, &br2684_devs) {
161 		net_dev = list_entry_brdev(lh);
162 
163 		list_for_each_entry(brvcc, &BRPRIV(net_dev)->brvccs, brvccs) {
164 			atm_vcc = brvcc->atmvcc;
165 			if (atm_vcc && brvcc->atmvcc->dev == atm_dev) {
166 
167 				if (atm_vcc->dev->signal == ATM_PHY_SIG_LOST)
168 					netif_carrier_off(net_dev);
169 				else
170 					netif_carrier_on(net_dev);
171 
172 			}
173 		}
174 	}
175 	read_unlock_irqrestore(&devs_lock, flags);
176 
177 	return NOTIFY_DONE;
178 }
179 
180 static struct notifier_block atm_dev_notifier = {
181 	.notifier_call = atm_dev_event,
182 };
183 
184 /* chained vcc->pop function.  Check if we should wake the netif_queue */
185 static void br2684_pop(struct atm_vcc *vcc, struct sk_buff *skb)
186 {
187 	struct br2684_vcc *brvcc = BR2684_VCC(vcc);
188 
189 	pr_debug("(vcc %p ; net_dev %p )\n", vcc, brvcc->device);
190 	brvcc->old_pop(vcc, skb);
191 
192 	/* If the queue space just went up from zero, wake */
193 	if (atomic_inc_return(&brvcc->qspace) == 1)
194 		netif_wake_queue(brvcc->device);
195 }
196 
197 /*
198  * Send a packet out a particular vcc.  Not to useful right now, but paves
199  * the way for multiple vcc's per itf.  Returns true if we can send,
200  * otherwise false
201  */
202 static int br2684_xmit_vcc(struct sk_buff *skb, struct net_device *dev,
203 			   struct br2684_vcc *brvcc)
204 {
205 	struct br2684_dev *brdev = BRPRIV(dev);
206 	struct atm_vcc *atmvcc;
207 	int minheadroom = (brvcc->encaps == e_llc) ?
208 		((brdev->payload == p_bridged) ?
209 			sizeof(llc_oui_pid_pad) : sizeof(llc_oui_ipv4)) :
210 		((brdev->payload == p_bridged) ? BR2684_PAD_LEN : 0);
211 
212 	if (skb_headroom(skb) < minheadroom) {
213 		struct sk_buff *skb2 = skb_realloc_headroom(skb, minheadroom);
214 		brvcc->copies_needed++;
215 		dev_kfree_skb(skb);
216 		if (skb2 == NULL) {
217 			brvcc->copies_failed++;
218 			return 0;
219 		}
220 		skb = skb2;
221 	}
222 
223 	if (brvcc->encaps == e_llc) {
224 		if (brdev->payload == p_bridged) {
225 			skb_push(skb, sizeof(llc_oui_pid_pad));
226 			skb_copy_to_linear_data(skb, llc_oui_pid_pad,
227 						sizeof(llc_oui_pid_pad));
228 		} else if (brdev->payload == p_routed) {
229 			unsigned short prot = ntohs(skb->protocol);
230 
231 			skb_push(skb, sizeof(llc_oui_ipv4));
232 			switch (prot) {
233 			case ETH_P_IP:
234 				skb_copy_to_linear_data(skb, llc_oui_ipv4,
235 							sizeof(llc_oui_ipv4));
236 				break;
237 			case ETH_P_IPV6:
238 				skb_copy_to_linear_data(skb, llc_oui_ipv6,
239 							sizeof(llc_oui_ipv6));
240 				break;
241 			default:
242 				dev_kfree_skb(skb);
243 				return 0;
244 			}
245 		}
246 	} else { /* e_vc */
247 		if (brdev->payload == p_bridged) {
248 			skb_push(skb, 2);
249 			memset(skb->data, 0, 2);
250 		}
251 	}
252 	skb_debug(skb);
253 
254 	ATM_SKB(skb)->vcc = atmvcc = brvcc->atmvcc;
255 	pr_debug("atm_skb(%p)->vcc(%p)->dev(%p)\n", skb, atmvcc, atmvcc->dev);
256 	atm_account_tx(atmvcc, skb);
257 	dev->stats.tx_packets++;
258 	dev->stats.tx_bytes += skb->len;
259 
260 	if (atomic_dec_return(&brvcc->qspace) < 1) {
261 		/* No more please! */
262 		netif_stop_queue(brvcc->device);
263 		/* We might have raced with br2684_pop() */
264 		if (unlikely(atomic_read(&brvcc->qspace) > 0))
265 			netif_wake_queue(brvcc->device);
266 	}
267 
268 	/* If this fails immediately, the skb will be freed and br2684_pop()
269 	   will wake the queue if appropriate. Just return an error so that
270 	   the stats are updated correctly */
271 	return !atmvcc->send(atmvcc, skb);
272 }
273 
274 static void br2684_release_cb(struct atm_vcc *atmvcc)
275 {
276 	struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
277 
278 	if (atomic_read(&brvcc->qspace) > 0)
279 		netif_wake_queue(brvcc->device);
280 
281 	if (brvcc->old_release_cb)
282 		brvcc->old_release_cb(atmvcc);
283 }
284 
285 static inline struct br2684_vcc *pick_outgoing_vcc(const struct sk_buff *skb,
286 						   const struct br2684_dev *brdev)
287 {
288 	return list_empty(&brdev->brvccs) ? NULL : list_entry_brvcc(brdev->brvccs.next);	/* 1 vcc/dev right now */
289 }
290 
291 static netdev_tx_t br2684_start_xmit(struct sk_buff *skb,
292 				     struct net_device *dev)
293 {
294 	struct br2684_dev *brdev = BRPRIV(dev);
295 	struct br2684_vcc *brvcc;
296 	struct atm_vcc *atmvcc;
297 	netdev_tx_t ret = NETDEV_TX_OK;
298 
299 	pr_debug("skb_dst(skb)=%p\n", skb_dst(skb));
300 	read_lock(&devs_lock);
301 	brvcc = pick_outgoing_vcc(skb, brdev);
302 	if (brvcc == NULL) {
303 		pr_debug("no vcc attached to dev %s\n", dev->name);
304 		dev->stats.tx_errors++;
305 		dev->stats.tx_carrier_errors++;
306 		/* netif_stop_queue(dev); */
307 		dev_kfree_skb(skb);
308 		goto out_devs;
309 	}
310 	atmvcc = brvcc->atmvcc;
311 
312 	bh_lock_sock(sk_atm(atmvcc));
313 
314 	if (test_bit(ATM_VF_RELEASED, &atmvcc->flags) ||
315 	    test_bit(ATM_VF_CLOSE, &atmvcc->flags) ||
316 	    !test_bit(ATM_VF_READY, &atmvcc->flags)) {
317 		dev->stats.tx_dropped++;
318 		dev_kfree_skb(skb);
319 		goto out;
320 	}
321 
322 	if (sock_owned_by_user(sk_atm(atmvcc))) {
323 		netif_stop_queue(brvcc->device);
324 		ret = NETDEV_TX_BUSY;
325 		goto out;
326 	}
327 
328 	if (!br2684_xmit_vcc(skb, dev, brvcc)) {
329 		/*
330 		 * We should probably use netif_*_queue() here, but that
331 		 * involves added complication.  We need to walk before
332 		 * we can run.
333 		 *
334 		 * Don't free here! this pointer might be no longer valid!
335 		 */
336 		dev->stats.tx_errors++;
337 		dev->stats.tx_fifo_errors++;
338 	}
339  out:
340 	bh_unlock_sock(sk_atm(atmvcc));
341  out_devs:
342 	read_unlock(&devs_lock);
343 	return ret;
344 }
345 
346 /*
347  * We remember when the MAC gets set, so we don't override it later with
348  * the ESI of the ATM card of the first VC
349  */
350 static int br2684_mac_addr(struct net_device *dev, void *p)
351 {
352 	int err = eth_mac_addr(dev, p);
353 	if (!err)
354 		BRPRIV(dev)->mac_was_set = 1;
355 	return err;
356 }
357 
358 #ifdef CONFIG_ATM_BR2684_IPFILTER
359 /* this IOCTL is experimental. */
360 static int br2684_setfilt(struct atm_vcc *atmvcc, void __user * arg)
361 {
362 	struct br2684_vcc *brvcc;
363 	struct br2684_filter_set fs;
364 
365 	if (copy_from_user(&fs, arg, sizeof fs))
366 		return -EFAULT;
367 	if (fs.ifspec.method != BR2684_FIND_BYNOTHING) {
368 		/*
369 		 * This is really a per-vcc thing, but we can also search
370 		 * by device.
371 		 */
372 		struct br2684_dev *brdev;
373 		read_lock(&devs_lock);
374 		brdev = BRPRIV(br2684_find_dev(&fs.ifspec));
375 		if (brdev == NULL || list_empty(&brdev->brvccs) ||
376 		    brdev->brvccs.next != brdev->brvccs.prev)	/* >1 VCC */
377 			brvcc = NULL;
378 		else
379 			brvcc = list_entry_brvcc(brdev->brvccs.next);
380 		read_unlock(&devs_lock);
381 		if (brvcc == NULL)
382 			return -ESRCH;
383 	} else
384 		brvcc = BR2684_VCC(atmvcc);
385 	memcpy(&brvcc->filter, &fs.filter, sizeof(brvcc->filter));
386 	return 0;
387 }
388 
389 /* Returns 1 if packet should be dropped */
390 static inline int
391 packet_fails_filter(__be16 type, struct br2684_vcc *brvcc, struct sk_buff *skb)
392 {
393 	if (brvcc->filter.netmask == 0)
394 		return 0;	/* no filter in place */
395 	if (type == htons(ETH_P_IP) &&
396 	    (((struct iphdr *)(skb->data))->daddr & brvcc->filter.
397 	     netmask) == brvcc->filter.prefix)
398 		return 0;
399 	if (type == htons(ETH_P_ARP))
400 		return 0;
401 	/*
402 	 * TODO: we should probably filter ARPs too.. don't want to have
403 	 * them returning values that don't make sense, or is that ok?
404 	 */
405 	return 1;		/* drop */
406 }
407 #endif /* CONFIG_ATM_BR2684_IPFILTER */
408 
409 static void br2684_close_vcc(struct br2684_vcc *brvcc)
410 {
411 	pr_debug("removing VCC %p from dev %p\n", brvcc, brvcc->device);
412 	write_lock_irq(&devs_lock);
413 	list_del(&brvcc->brvccs);
414 	write_unlock_irq(&devs_lock);
415 	brvcc->atmvcc->user_back = NULL;	/* what about vcc->recvq ??? */
416 	brvcc->atmvcc->release_cb = brvcc->old_release_cb;
417 	brvcc->old_push(brvcc->atmvcc, NULL);	/* pass on the bad news */
418 	module_put(brvcc->old_owner);
419 	kfree(brvcc);
420 }
421 
422 /* when AAL5 PDU comes in: */
423 static void br2684_push(struct atm_vcc *atmvcc, struct sk_buff *skb)
424 {
425 	struct br2684_vcc *brvcc = BR2684_VCC(atmvcc);
426 	struct net_device *net_dev = brvcc->device;
427 	struct br2684_dev *brdev = BRPRIV(net_dev);
428 
429 	pr_debug("\n");
430 
431 	if (unlikely(skb == NULL)) {
432 		/* skb==NULL means VCC is being destroyed */
433 		br2684_close_vcc(brvcc);
434 		if (list_empty(&brdev->brvccs)) {
435 			write_lock_irq(&devs_lock);
436 			list_del(&brdev->br2684_devs);
437 			write_unlock_irq(&devs_lock);
438 			unregister_netdev(net_dev);
439 			free_netdev(net_dev);
440 		}
441 		return;
442 	}
443 
444 	skb_debug(skb);
445 	atm_return(atmvcc, skb->truesize);
446 	pr_debug("skb from brdev %p\n", brdev);
447 	if (brvcc->encaps == e_llc) {
448 
449 		if (skb->len > 7 && skb->data[7] == 0x01)
450 			__skb_trim(skb, skb->len - 4);
451 
452 		/* accept packets that have "ipv[46]" in the snap header */
453 		if ((skb->len >= (sizeof(llc_oui_ipv4))) &&
454 		    (memcmp(skb->data, llc_oui_ipv4,
455 			    sizeof(llc_oui_ipv4) - BR2684_ETHERTYPE_LEN) == 0)) {
456 			if (memcmp(skb->data + 6, ethertype_ipv6,
457 				   sizeof(ethertype_ipv6)) == 0)
458 				skb->protocol = htons(ETH_P_IPV6);
459 			else if (memcmp(skb->data + 6, ethertype_ipv4,
460 					sizeof(ethertype_ipv4)) == 0)
461 				skb->protocol = htons(ETH_P_IP);
462 			else
463 				goto error;
464 			skb_pull(skb, sizeof(llc_oui_ipv4));
465 			skb_reset_network_header(skb);
466 			skb->pkt_type = PACKET_HOST;
467 		/*
468 		 * Let us waste some time for checking the encapsulation.
469 		 * Note, that only 7 char is checked so frames with a valid FCS
470 		 * are also accepted (but FCS is not checked of course).
471 		 */
472 		} else if ((skb->len >= sizeof(llc_oui_pid_pad)) &&
473 			   (memcmp(skb->data, llc_oui_pid_pad, 7) == 0)) {
474 			skb_pull(skb, sizeof(llc_oui_pid_pad));
475 			skb->protocol = eth_type_trans(skb, net_dev);
476 		} else
477 			goto error;
478 
479 	} else { /* e_vc */
480 		if (brdev->payload == p_routed) {
481 			struct iphdr *iph;
482 
483 			skb_reset_network_header(skb);
484 			iph = ip_hdr(skb);
485 			if (iph->version == 4)
486 				skb->protocol = htons(ETH_P_IP);
487 			else if (iph->version == 6)
488 				skb->protocol = htons(ETH_P_IPV6);
489 			else
490 				goto error;
491 			skb->pkt_type = PACKET_HOST;
492 		} else { /* p_bridged */
493 			/* first 2 chars should be 0 */
494 			if (memcmp(skb->data, pad, BR2684_PAD_LEN) != 0)
495 				goto error;
496 			skb_pull(skb, BR2684_PAD_LEN);
497 			skb->protocol = eth_type_trans(skb, net_dev);
498 		}
499 	}
500 
501 #ifdef CONFIG_ATM_BR2684_IPFILTER
502 	if (unlikely(packet_fails_filter(skb->protocol, brvcc, skb)))
503 		goto dropped;
504 #endif /* CONFIG_ATM_BR2684_IPFILTER */
505 	skb->dev = net_dev;
506 	ATM_SKB(skb)->vcc = atmvcc;	/* needed ? */
507 	pr_debug("received packet's protocol: %x\n", ntohs(skb->protocol));
508 	skb_debug(skb);
509 	/* sigh, interface is down? */
510 	if (unlikely(!(net_dev->flags & IFF_UP)))
511 		goto dropped;
512 	net_dev->stats.rx_packets++;
513 	net_dev->stats.rx_bytes += skb->len;
514 	memset(ATM_SKB(skb), 0, sizeof(struct atm_skb_data));
515 	netif_rx(skb);
516 	return;
517 
518 dropped:
519 	net_dev->stats.rx_dropped++;
520 	goto free_skb;
521 error:
522 	net_dev->stats.rx_errors++;
523 free_skb:
524 	dev_kfree_skb(skb);
525 }
526 
527 /*
528  * Assign a vcc to a dev
529  * Note: we do not have explicit unassign, but look at _push()
530  */
531 static int br2684_regvcc(struct atm_vcc *atmvcc, void __user * arg)
532 {
533 	struct br2684_vcc *brvcc;
534 	struct br2684_dev *brdev;
535 	struct net_device *net_dev;
536 	struct atm_backend_br2684 be;
537 	int err;
538 
539 	if (copy_from_user(&be, arg, sizeof be))
540 		return -EFAULT;
541 	brvcc = kzalloc(sizeof(struct br2684_vcc), GFP_KERNEL);
542 	if (!brvcc)
543 		return -ENOMEM;
544 	/*
545 	 * Allow two packets in the ATM queue. One actually being sent, and one
546 	 * for the ATM 'TX done' handler to send. It shouldn't take long to get
547 	 * the next one from the netdev queue, when we need it. More than that
548 	 * would be bufferbloat.
549 	 */
550 	atomic_set(&brvcc->qspace, 2);
551 	write_lock_irq(&devs_lock);
552 	net_dev = br2684_find_dev(&be.ifspec);
553 	if (net_dev == NULL) {
554 		pr_err("tried to attach to non-existent device\n");
555 		err = -ENXIO;
556 		goto error;
557 	}
558 	brdev = BRPRIV(net_dev);
559 	if (atmvcc->push == NULL) {
560 		err = -EBADFD;
561 		goto error;
562 	}
563 	if (!list_empty(&brdev->brvccs)) {
564 		/* Only 1 VCC/dev right now */
565 		err = -EEXIST;
566 		goto error;
567 	}
568 	if (be.fcs_in != BR2684_FCSIN_NO ||
569 	    be.fcs_out != BR2684_FCSOUT_NO ||
570 	    be.fcs_auto || be.has_vpiid || be.send_padding ||
571 	    (be.encaps != BR2684_ENCAPS_VC &&
572 	     be.encaps != BR2684_ENCAPS_LLC) ||
573 	    be.min_size != 0) {
574 		err = -EINVAL;
575 		goto error;
576 	}
577 	pr_debug("vcc=%p, encaps=%d, brvcc=%p\n", atmvcc, be.encaps, brvcc);
578 	if (list_empty(&brdev->brvccs) && !brdev->mac_was_set) {
579 		unsigned char *esi = atmvcc->dev->esi;
580 		if (esi[0] | esi[1] | esi[2] | esi[3] | esi[4] | esi[5])
581 			dev_addr_set(net_dev, esi);
582 		else
583 			net_dev->dev_addr[2] = 1;
584 	}
585 	list_add(&brvcc->brvccs, &brdev->brvccs);
586 	write_unlock_irq(&devs_lock);
587 	brvcc->device = net_dev;
588 	brvcc->atmvcc = atmvcc;
589 	atmvcc->user_back = brvcc;
590 	brvcc->encaps = (enum br2684_encaps)be.encaps;
591 	brvcc->old_push = atmvcc->push;
592 	brvcc->old_pop = atmvcc->pop;
593 	brvcc->old_release_cb = atmvcc->release_cb;
594 	brvcc->old_owner = atmvcc->owner;
595 	barrier();
596 	atmvcc->push = br2684_push;
597 	atmvcc->pop = br2684_pop;
598 	atmvcc->release_cb = br2684_release_cb;
599 	atmvcc->owner = THIS_MODULE;
600 
601 	/* initialize netdev carrier state */
602 	if (atmvcc->dev->signal == ATM_PHY_SIG_LOST)
603 		netif_carrier_off(net_dev);
604 	else
605 		netif_carrier_on(net_dev);
606 
607 	__module_get(THIS_MODULE);
608 
609 	/* re-process everything received between connection setup and
610 	   backend setup */
611 	vcc_process_recv_queue(atmvcc);
612 	return 0;
613 
614 error:
615 	write_unlock_irq(&devs_lock);
616 	kfree(brvcc);
617 	return err;
618 }
619 
620 static const struct net_device_ops br2684_netdev_ops = {
621 	.ndo_start_xmit 	= br2684_start_xmit,
622 	.ndo_set_mac_address	= br2684_mac_addr,
623 	.ndo_validate_addr	= eth_validate_addr,
624 };
625 
626 static const struct net_device_ops br2684_netdev_ops_routed = {
627 	.ndo_start_xmit 	= br2684_start_xmit,
628 	.ndo_set_mac_address	= br2684_mac_addr,
629 };
630 
631 static void br2684_setup(struct net_device *netdev)
632 {
633 	struct br2684_dev *brdev = BRPRIV(netdev);
634 
635 	ether_setup(netdev);
636 	netdev->hard_header_len += sizeof(llc_oui_pid_pad); /* worst case */
637 	brdev->net_dev = netdev;
638 
639 	netdev->netdev_ops = &br2684_netdev_ops;
640 
641 	INIT_LIST_HEAD(&brdev->brvccs);
642 }
643 
644 static void br2684_setup_routed(struct net_device *netdev)
645 {
646 	struct br2684_dev *brdev = BRPRIV(netdev);
647 
648 	brdev->net_dev = netdev;
649 	netdev->hard_header_len = sizeof(llc_oui_ipv4); /* worst case */
650 	netdev->netdev_ops = &br2684_netdev_ops_routed;
651 	netdev->addr_len = 0;
652 	netdev->mtu = ETH_DATA_LEN;
653 	netdev->min_mtu = 0;
654 	netdev->max_mtu = ETH_MAX_MTU;
655 	netdev->type = ARPHRD_PPP;
656 	netdev->flags = IFF_POINTOPOINT | IFF_NOARP | IFF_MULTICAST;
657 	netdev->tx_queue_len = 100;
658 	INIT_LIST_HEAD(&brdev->brvccs);
659 }
660 
661 static int br2684_create(void __user *arg)
662 {
663 	int err;
664 	struct net_device *netdev;
665 	struct br2684_dev *brdev;
666 	struct atm_newif_br2684 ni;
667 	enum br2684_payload payload;
668 
669 	pr_debug("\n");
670 
671 	if (copy_from_user(&ni, arg, sizeof ni))
672 		return -EFAULT;
673 
674 	if (ni.media & BR2684_FLAG_ROUTED)
675 		payload = p_routed;
676 	else
677 		payload = p_bridged;
678 	ni.media &= 0xffff;	/* strip flags */
679 
680 	if (ni.media != BR2684_MEDIA_ETHERNET || ni.mtu != 1500)
681 		return -EINVAL;
682 
683 	netdev = alloc_netdev(sizeof(struct br2684_dev),
684 			      ni.ifname[0] ? ni.ifname : "nas%d",
685 			      NET_NAME_UNKNOWN,
686 			      (payload == p_routed) ? br2684_setup_routed : br2684_setup);
687 	if (!netdev)
688 		return -ENOMEM;
689 
690 	brdev = BRPRIV(netdev);
691 
692 	pr_debug("registered netdev %s\n", netdev->name);
693 	/* open, stop, do_ioctl ? */
694 	err = register_netdev(netdev);
695 	if (err < 0) {
696 		pr_err("register_netdev failed\n");
697 		free_netdev(netdev);
698 		return err;
699 	}
700 
701 	write_lock_irq(&devs_lock);
702 
703 	brdev->payload = payload;
704 
705 	if (list_empty(&br2684_devs)) {
706 		/* 1st br2684 device */
707 		brdev->number = 1;
708 	} else
709 		brdev->number = BRPRIV(list_entry_brdev(br2684_devs.prev))->number + 1;
710 
711 	list_add_tail(&brdev->br2684_devs, &br2684_devs);
712 	write_unlock_irq(&devs_lock);
713 	return 0;
714 }
715 
716 /*
717  * This handles ioctls actually performed on our vcc - we must return
718  * -ENOIOCTLCMD for any unrecognized ioctl
719  */
720 static int br2684_ioctl(struct socket *sock, unsigned int cmd,
721 			unsigned long arg)
722 {
723 	struct atm_vcc *atmvcc = ATM_SD(sock);
724 	void __user *argp = (void __user *)arg;
725 	atm_backend_t b;
726 
727 	int err;
728 	switch (cmd) {
729 	case ATM_SETBACKEND:
730 	case ATM_NEWBACKENDIF:
731 		err = get_user(b, (atm_backend_t __user *) argp);
732 		if (err)
733 			return -EFAULT;
734 		if (b != ATM_BACKEND_BR2684)
735 			return -ENOIOCTLCMD;
736 		if (!capable(CAP_NET_ADMIN))
737 			return -EPERM;
738 		if (cmd == ATM_SETBACKEND) {
739 			if (sock->state != SS_CONNECTED)
740 				return -EINVAL;
741 			return br2684_regvcc(atmvcc, argp);
742 		} else {
743 			return br2684_create(argp);
744 		}
745 #ifdef CONFIG_ATM_BR2684_IPFILTER
746 	case BR2684_SETFILT:
747 		if (atmvcc->push != br2684_push)
748 			return -ENOIOCTLCMD;
749 		if (!capable(CAP_NET_ADMIN))
750 			return -EPERM;
751 		err = br2684_setfilt(atmvcc, argp);
752 
753 		return err;
754 #endif /* CONFIG_ATM_BR2684_IPFILTER */
755 	}
756 	return -ENOIOCTLCMD;
757 }
758 
759 static struct atm_ioctl br2684_ioctl_ops = {
760 	.owner = THIS_MODULE,
761 	.ioctl = br2684_ioctl,
762 };
763 
764 #ifdef CONFIG_PROC_FS
765 static void *br2684_seq_start(struct seq_file *seq, loff_t * pos)
766 	__acquires(devs_lock)
767 {
768 	read_lock(&devs_lock);
769 	return seq_list_start(&br2684_devs, *pos);
770 }
771 
772 static void *br2684_seq_next(struct seq_file *seq, void *v, loff_t * pos)
773 {
774 	return seq_list_next(v, &br2684_devs, pos);
775 }
776 
777 static void br2684_seq_stop(struct seq_file *seq, void *v)
778 	__releases(devs_lock)
779 {
780 	read_unlock(&devs_lock);
781 }
782 
783 static int br2684_seq_show(struct seq_file *seq, void *v)
784 {
785 	const struct br2684_dev *brdev = list_entry(v, struct br2684_dev,
786 						    br2684_devs);
787 	const struct net_device *net_dev = brdev->net_dev;
788 	const struct br2684_vcc *brvcc;
789 
790 	seq_printf(seq, "dev %.16s: num=%d, mac=%pM (%s)\n",
791 		   net_dev->name,
792 		   brdev->number,
793 		   net_dev->dev_addr,
794 		   brdev->mac_was_set ? "set" : "auto");
795 
796 	list_for_each_entry(brvcc, &brdev->brvccs, brvccs) {
797 		seq_printf(seq, "  vcc %d.%d.%d: encaps=%s payload=%s"
798 			   ", failed copies %u/%u"
799 			   "\n", brvcc->atmvcc->dev->number,
800 			   brvcc->atmvcc->vpi, brvcc->atmvcc->vci,
801 			   (brvcc->encaps == e_llc) ? "LLC" : "VC",
802 			   (brdev->payload == p_bridged) ? "bridged" : "routed",
803 			   brvcc->copies_failed, brvcc->copies_needed);
804 #ifdef CONFIG_ATM_BR2684_IPFILTER
805 		if (brvcc->filter.netmask != 0)
806 			seq_printf(seq, "    filter=%pI4/%pI4\n",
807 				   &brvcc->filter.prefix,
808 				   &brvcc->filter.netmask);
809 #endif /* CONFIG_ATM_BR2684_IPFILTER */
810 	}
811 	return 0;
812 }
813 
814 static const struct seq_operations br2684_seq_ops = {
815 	.start = br2684_seq_start,
816 	.next = br2684_seq_next,
817 	.stop = br2684_seq_stop,
818 	.show = br2684_seq_show,
819 };
820 
821 extern struct proc_dir_entry *atm_proc_root;	/* from proc.c */
822 #endif /* CONFIG_PROC_FS */
823 
824 static int __init br2684_init(void)
825 {
826 #ifdef CONFIG_PROC_FS
827 	struct proc_dir_entry *p;
828 	p = proc_create_seq("br2684", 0, atm_proc_root, &br2684_seq_ops);
829 	if (p == NULL)
830 		return -ENOMEM;
831 #endif
832 	register_atm_ioctl(&br2684_ioctl_ops);
833 	register_atmdevice_notifier(&atm_dev_notifier);
834 	return 0;
835 }
836 
837 static void __exit br2684_exit(void)
838 {
839 	struct net_device *net_dev;
840 	struct br2684_dev *brdev;
841 	struct br2684_vcc *brvcc;
842 	deregister_atm_ioctl(&br2684_ioctl_ops);
843 
844 #ifdef CONFIG_PROC_FS
845 	remove_proc_entry("br2684", atm_proc_root);
846 #endif
847 
848 
849 	unregister_atmdevice_notifier(&atm_dev_notifier);
850 
851 	while (!list_empty(&br2684_devs)) {
852 		net_dev = list_entry_brdev(br2684_devs.next);
853 		brdev = BRPRIV(net_dev);
854 		while (!list_empty(&brdev->brvccs)) {
855 			brvcc = list_entry_brvcc(brdev->brvccs.next);
856 			br2684_close_vcc(brvcc);
857 		}
858 
859 		list_del(&brdev->br2684_devs);
860 		unregister_netdev(net_dev);
861 		free_netdev(net_dev);
862 	}
863 }
864 
865 module_init(br2684_init);
866 module_exit(br2684_exit);
867 
868 MODULE_AUTHOR("Marcell GAL");
869 MODULE_DESCRIPTION("RFC2684 bridged protocols over ATM/AAL5");
870 MODULE_LICENSE("GPL");
871