xref: /linux/arch/um/drivers/net_kern.c (revision dbcedec3a31119d7594baacc743300d127c99c56)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright (C) 2001 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
4  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and
5  * James Leu (jleu@mindspring.net).
6  * Copyright (C) 2001 by various other people who didn't put their name here.
7  */
8 
9 #include <linux/memblock.h>
10 #include <linux/etherdevice.h>
11 #include <linux/ethtool.h>
12 #include <linux/inetdevice.h>
13 #include <linux/init.h>
14 #include <linux/list.h>
15 #include <linux/netdevice.h>
16 #include <linux/platform_device.h>
17 #include <linux/rtnetlink.h>
18 #include <linux/skbuff.h>
19 #include <linux/slab.h>
20 #include <linux/spinlock.h>
21 #include <init.h>
22 #include <irq_kern.h>
23 #include <irq_user.h>
24 #include "mconsole_kern.h"
25 #include <net_kern.h>
26 #include <net_user.h>
27 
28 #define DRIVER_NAME "uml-netdev"
29 
30 static DEFINE_SPINLOCK(opened_lock);
31 static LIST_HEAD(opened);
32 
33 /*
34  * The drop_skb is used when we can't allocate an skb.  The
35  * packet is read into drop_skb in order to get the data off the
36  * connection to the host.
37  * It is reallocated whenever a maximum packet size is seen which is
38  * larger than any seen before.  update_drop_skb is called from
39  * eth_configure when a new interface is added.
40  */
41 static DEFINE_SPINLOCK(drop_lock);
42 static struct sk_buff *drop_skb;
43 static int drop_max;
44 
45 static int update_drop_skb(int max)
46 {
47 	struct sk_buff *new;
48 	unsigned long flags;
49 	int err = 0;
50 
51 	spin_lock_irqsave(&drop_lock, flags);
52 
53 	if (max <= drop_max)
54 		goto out;
55 
56 	err = -ENOMEM;
57 	new = dev_alloc_skb(max);
58 	if (new == NULL)
59 		goto out;
60 
61 	skb_put(new, max);
62 
63 	kfree_skb(drop_skb);
64 	drop_skb = new;
65 	drop_max = max;
66 	err = 0;
67 out:
68 	spin_unlock_irqrestore(&drop_lock, flags);
69 
70 	return err;
71 }
72 
73 static int uml_net_rx(struct net_device *dev)
74 {
75 	struct uml_net_private *lp = netdev_priv(dev);
76 	int pkt_len;
77 	struct sk_buff *skb;
78 
79 	/* If we can't allocate memory, try again next round. */
80 	skb = dev_alloc_skb(lp->max_packet);
81 	if (skb == NULL) {
82 		drop_skb->dev = dev;
83 		/* Read a packet into drop_skb and don't do anything with it. */
84 		(*lp->read)(lp->fd, drop_skb, lp);
85 		dev->stats.rx_dropped++;
86 		return 0;
87 	}
88 
89 	skb->dev = dev;
90 	skb_put(skb, lp->max_packet);
91 	skb_reset_mac_header(skb);
92 	pkt_len = (*lp->read)(lp->fd, skb, lp);
93 
94 	if (pkt_len > 0) {
95 		skb_trim(skb, pkt_len);
96 		skb->protocol = (*lp->protocol)(skb);
97 
98 		dev->stats.rx_bytes += skb->len;
99 		dev->stats.rx_packets++;
100 		netif_rx(skb);
101 		return pkt_len;
102 	}
103 
104 	kfree_skb(skb);
105 	return pkt_len;
106 }
107 
108 static void uml_dev_close(struct work_struct *work)
109 {
110 	struct uml_net_private *lp =
111 		container_of(work, struct uml_net_private, work);
112 	dev_close(lp->dev);
113 }
114 
115 static irqreturn_t uml_net_interrupt(int irq, void *dev_id)
116 {
117 	struct net_device *dev = dev_id;
118 	struct uml_net_private *lp = netdev_priv(dev);
119 	int err;
120 
121 	if (!netif_running(dev))
122 		return IRQ_NONE;
123 
124 	spin_lock(&lp->lock);
125 	while ((err = uml_net_rx(dev)) > 0) ;
126 	if (err < 0) {
127 		printk(KERN_ERR
128 		       "Device '%s' read returned %d, shutting it down\n",
129 		       dev->name, err);
130 		/* dev_close can't be called in interrupt context, and takes
131 		 * again lp->lock.
132 		 * And dev_close() can be safely called multiple times on the
133 		 * same device, since it tests for (dev->flags & IFF_UP). So
134 		 * there's no harm in delaying the device shutdown.
135 		 * Furthermore, the workqueue will not re-enqueue an already
136 		 * enqueued work item. */
137 		schedule_work(&lp->work);
138 		goto out;
139 	}
140 out:
141 	spin_unlock(&lp->lock);
142 	return IRQ_HANDLED;
143 }
144 
145 static int uml_net_open(struct net_device *dev)
146 {
147 	struct uml_net_private *lp = netdev_priv(dev);
148 	int err;
149 
150 	if (lp->fd >= 0) {
151 		err = -ENXIO;
152 		goto out;
153 	}
154 
155 	lp->fd = (*lp->open)(&lp->user);
156 	if (lp->fd < 0) {
157 		err = lp->fd;
158 		goto out;
159 	}
160 
161 	err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
162 			     IRQF_SHARED, dev->name, dev);
163 	if (err < 0) {
164 		printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
165 		err = -ENETUNREACH;
166 		goto out_close;
167 	}
168 
169 	netif_start_queue(dev);
170 
171 	/* clear buffer - it can happen that the host side of the interface
172 	 * is full when we get here.  In this case, new data is never queued,
173 	 * SIGIOs never arrive, and the net never works.
174 	 */
175 	while ((err = uml_net_rx(dev)) > 0) ;
176 
177 	spin_lock(&opened_lock);
178 	list_add(&lp->list, &opened);
179 	spin_unlock(&opened_lock);
180 
181 	return 0;
182 out_close:
183 	if (lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
184 	lp->fd = -1;
185 out:
186 	return err;
187 }
188 
189 static int uml_net_close(struct net_device *dev)
190 {
191 	struct uml_net_private *lp = netdev_priv(dev);
192 
193 	netif_stop_queue(dev);
194 
195 	um_free_irq(dev->irq, dev);
196 	if (lp->close != NULL)
197 		(*lp->close)(lp->fd, &lp->user);
198 	lp->fd = -1;
199 
200 	spin_lock(&opened_lock);
201 	list_del(&lp->list);
202 	spin_unlock(&opened_lock);
203 
204 	return 0;
205 }
206 
207 static netdev_tx_t uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
208 {
209 	struct uml_net_private *lp = netdev_priv(dev);
210 	unsigned long flags;
211 	int len;
212 
213 	netif_stop_queue(dev);
214 
215 	spin_lock_irqsave(&lp->lock, flags);
216 
217 	len = (*lp->write)(lp->fd, skb, lp);
218 	skb_tx_timestamp(skb);
219 
220 	if (len == skb->len) {
221 		dev->stats.tx_packets++;
222 		dev->stats.tx_bytes += skb->len;
223 		netif_trans_update(dev);
224 		netif_start_queue(dev);
225 
226 		/* this is normally done in the interrupt when tx finishes */
227 		netif_wake_queue(dev);
228 	}
229 	else if (len == 0) {
230 		netif_start_queue(dev);
231 		dev->stats.tx_dropped++;
232 	}
233 	else {
234 		netif_start_queue(dev);
235 		printk(KERN_ERR "uml_net_start_xmit: failed(%d)\n", len);
236 	}
237 
238 	spin_unlock_irqrestore(&lp->lock, flags);
239 
240 	dev_consume_skb_any(skb);
241 
242 	return NETDEV_TX_OK;
243 }
244 
245 static void uml_net_set_multicast_list(struct net_device *dev)
246 {
247 	return;
248 }
249 
250 static void uml_net_tx_timeout(struct net_device *dev, unsigned int txqueue)
251 {
252 	netif_trans_update(dev);
253 	netif_wake_queue(dev);
254 }
255 
256 #ifdef CONFIG_NET_POLL_CONTROLLER
257 static void uml_net_poll_controller(struct net_device *dev)
258 {
259 	disable_irq(dev->irq);
260 	uml_net_interrupt(dev->irq, dev);
261 	enable_irq(dev->irq);
262 }
263 #endif
264 
265 static void uml_net_get_drvinfo(struct net_device *dev,
266 				struct ethtool_drvinfo *info)
267 {
268 	strscpy(info->driver, DRIVER_NAME);
269 }
270 
271 static const struct ethtool_ops uml_net_ethtool_ops = {
272 	.get_drvinfo	= uml_net_get_drvinfo,
273 	.get_link	= ethtool_op_get_link,
274 	.get_ts_info	= ethtool_op_get_ts_info,
275 };
276 
277 void uml_net_setup_etheraddr(struct net_device *dev, char *str)
278 {
279 	u8 addr[ETH_ALEN];
280 	char *end;
281 	int i;
282 
283 	if (str == NULL)
284 		goto random;
285 
286 	for (i = 0; i < 6; i++) {
287 		addr[i] = simple_strtoul(str, &end, 16);
288 		if ((end == str) ||
289 		   ((*end != ':') && (*end != ',') && (*end != '\0'))) {
290 			printk(KERN_ERR
291 			       "setup_etheraddr: failed to parse '%s' "
292 			       "as an ethernet address\n", str);
293 			goto random;
294 		}
295 		str = end + 1;
296 	}
297 	if (is_multicast_ether_addr(addr)) {
298 		printk(KERN_ERR
299 		       "Attempt to assign a multicast ethernet address to a "
300 		       "device disallowed\n");
301 		goto random;
302 	}
303 	if (!is_valid_ether_addr(addr)) {
304 		printk(KERN_ERR
305 		       "Attempt to assign an invalid ethernet address to a "
306 		       "device disallowed\n");
307 		goto random;
308 	}
309 	if (!is_local_ether_addr(addr)) {
310 		printk(KERN_WARNING
311 		       "Warning: Assigning a globally valid ethernet "
312 		       "address to a device\n");
313 		printk(KERN_WARNING "You should set the 2nd rightmost bit in "
314 		       "the first byte of the MAC,\n");
315 		printk(KERN_WARNING "i.e. %02x:%02x:%02x:%02x:%02x:%02x\n",
316 		       addr[0] | 0x02, addr[1], addr[2], addr[3], addr[4],
317 		       addr[5]);
318 	}
319 	eth_hw_addr_set(dev, addr);
320 	return;
321 
322 random:
323 	printk(KERN_INFO
324 	       "Choosing a random ethernet address for device %s\n", dev->name);
325 	eth_hw_addr_random(dev);
326 }
327 
328 static DEFINE_SPINLOCK(devices_lock);
329 static LIST_HEAD(devices);
330 
331 static struct platform_driver uml_net_driver = {
332 	.driver = {
333 		.name  = DRIVER_NAME,
334 	},
335 };
336 
337 static void net_device_release(struct device *dev)
338 {
339 	struct uml_net *device = dev_get_drvdata(dev);
340 	struct net_device *netdev = device->dev;
341 	struct uml_net_private *lp = netdev_priv(netdev);
342 
343 	if (lp->remove != NULL)
344 		(*lp->remove)(&lp->user);
345 	list_del(&device->list);
346 	kfree(device);
347 	free_netdev(netdev);
348 }
349 
350 static const struct net_device_ops uml_netdev_ops = {
351 	.ndo_open 		= uml_net_open,
352 	.ndo_stop 		= uml_net_close,
353 	.ndo_start_xmit 	= uml_net_start_xmit,
354 	.ndo_set_rx_mode	= uml_net_set_multicast_list,
355 	.ndo_tx_timeout 	= uml_net_tx_timeout,
356 	.ndo_set_mac_address	= eth_mac_addr,
357 	.ndo_validate_addr	= eth_validate_addr,
358 #ifdef CONFIG_NET_POLL_CONTROLLER
359 	.ndo_poll_controller = uml_net_poll_controller,
360 #endif
361 };
362 
363 /*
364  * Ensures that platform_driver_register is called only once by
365  * eth_configure.  Will be set in an initcall.
366  */
367 static int driver_registered;
368 
369 static void eth_configure(int n, void *init, char *mac,
370 			  struct transport *transport, gfp_t gfp_mask)
371 {
372 	struct uml_net *device;
373 	struct net_device *dev;
374 	struct uml_net_private *lp;
375 	int err, size;
376 
377 	size = transport->private_size + sizeof(struct uml_net_private);
378 
379 	device = kzalloc(sizeof(*device), gfp_mask);
380 	if (device == NULL) {
381 		printk(KERN_ERR "eth_configure failed to allocate struct "
382 		       "uml_net\n");
383 		return;
384 	}
385 
386 	dev = alloc_etherdev(size);
387 	if (dev == NULL) {
388 		printk(KERN_ERR "eth_configure: failed to allocate struct "
389 		       "net_device for eth%d\n", n);
390 		goto out_free_device;
391 	}
392 
393 	INIT_LIST_HEAD(&device->list);
394 	device->index = n;
395 
396 	/* If this name ends up conflicting with an existing registered
397 	 * netdevice, that is OK, register_netdev{,ice}() will notice this
398 	 * and fail.
399 	 */
400 	snprintf(dev->name, sizeof(dev->name), "eth%d", n);
401 
402 	uml_net_setup_etheraddr(dev, mac);
403 
404 	printk(KERN_INFO "Netdevice %d (%pM) : ", n, dev->dev_addr);
405 
406 	lp = netdev_priv(dev);
407 	/* This points to the transport private data. It's still clear, but we
408 	 * must memset it to 0 *now*. Let's help the drivers. */
409 	memset(lp, 0, size);
410 	INIT_WORK(&lp->work, uml_dev_close);
411 
412 	/* sysfs register */
413 	if (!driver_registered) {
414 		platform_driver_register(&uml_net_driver);
415 		driver_registered = 1;
416 	}
417 	device->pdev.id = n;
418 	device->pdev.name = DRIVER_NAME;
419 	device->pdev.dev.release = net_device_release;
420 	dev_set_drvdata(&device->pdev.dev, device);
421 	if (platform_device_register(&device->pdev))
422 		goto out_free_netdev;
423 	SET_NETDEV_DEV(dev,&device->pdev.dev);
424 
425 	device->dev = dev;
426 
427 	/*
428 	 * These just fill in a data structure, so there's no failure
429 	 * to be worried about.
430 	 */
431 	(*transport->kern->init)(dev, init);
432 
433 	*lp = ((struct uml_net_private)
434 		{ .list  		= LIST_HEAD_INIT(lp->list),
435 		  .dev 			= dev,
436 		  .fd 			= -1,
437 		  .mac 			= { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
438 		  .max_packet		= transport->user->max_packet,
439 		  .protocol 		= transport->kern->protocol,
440 		  .open 		= transport->user->open,
441 		  .close 		= transport->user->close,
442 		  .remove 		= transport->user->remove,
443 		  .read 		= transport->kern->read,
444 		  .write 		= transport->kern->write,
445 		  .add_address 		= transport->user->add_address,
446 		  .delete_address  	= transport->user->delete_address });
447 
448 	spin_lock_init(&lp->lock);
449 	memcpy(lp->mac, dev->dev_addr, sizeof(lp->mac));
450 
451 	if ((transport->user->init != NULL) &&
452 	    ((*transport->user->init)(&lp->user, dev) != 0))
453 		goto out_unregister;
454 
455 	dev->mtu = transport->user->mtu;
456 	dev->netdev_ops = &uml_netdev_ops;
457 	dev->ethtool_ops = &uml_net_ethtool_ops;
458 	dev->watchdog_timeo = (HZ >> 1);
459 	dev->irq = UM_ETH_IRQ;
460 
461 	err = update_drop_skb(lp->max_packet);
462 	if (err)
463 		goto out_undo_user_init;
464 
465 	rtnl_lock();
466 	err = register_netdevice(dev);
467 	rtnl_unlock();
468 	if (err)
469 		goto out_undo_user_init;
470 
471 	spin_lock(&devices_lock);
472 	list_add(&device->list, &devices);
473 	spin_unlock(&devices_lock);
474 
475 	return;
476 
477 out_undo_user_init:
478 	if (transport->user->remove != NULL)
479 		(*transport->user->remove)(&lp->user);
480 out_unregister:
481 	platform_device_unregister(&device->pdev);
482 	return; /* platform_device_unregister frees dev and device */
483 out_free_netdev:
484 	free_netdev(dev);
485 out_free_device:
486 	kfree(device);
487 }
488 
489 static struct uml_net *find_device(int n)
490 {
491 	struct uml_net *device;
492 	struct list_head *ele;
493 
494 	spin_lock(&devices_lock);
495 	list_for_each(ele, &devices) {
496 		device = list_entry(ele, struct uml_net, list);
497 		if (device->index == n)
498 			goto out;
499 	}
500 	device = NULL;
501  out:
502 	spin_unlock(&devices_lock);
503 	return device;
504 }
505 
506 static int eth_parse(char *str, int *index_out, char **str_out,
507 		     char **error_out)
508 {
509 	char *end;
510 	int n, err = -EINVAL;
511 
512 	n = simple_strtoul(str, &end, 0);
513 	if (end == str) {
514 		*error_out = "Bad device number";
515 		return err;
516 	}
517 
518 	str = end;
519 	if (*str != '=') {
520 		*error_out = "Expected '=' after device number";
521 		return err;
522 	}
523 
524 	str++;
525 	if (find_device(n)) {
526 		*error_out = "Device already configured";
527 		return err;
528 	}
529 
530 	*index_out = n;
531 	*str_out = str;
532 	return 0;
533 }
534 
535 struct eth_init {
536 	struct list_head list;
537 	char *init;
538 	int index;
539 };
540 
541 static DEFINE_SPINLOCK(transports_lock);
542 static LIST_HEAD(transports);
543 
544 /* Filled in during early boot */
545 static LIST_HEAD(eth_cmd_line);
546 
547 static int check_transport(struct transport *transport, char *eth, int n,
548 			   void **init_out, char **mac_out, gfp_t gfp_mask)
549 {
550 	int len;
551 
552 	len = strlen(transport->name);
553 	if (strncmp(eth, transport->name, len))
554 		return 0;
555 
556 	eth += len;
557 	if (*eth == ',')
558 		eth++;
559 	else if (*eth != '\0')
560 		return 0;
561 
562 	*init_out = kmalloc(transport->setup_size, gfp_mask);
563 	if (*init_out == NULL)
564 		return 1;
565 
566 	if (!transport->setup(eth, mac_out, *init_out)) {
567 		kfree(*init_out);
568 		*init_out = NULL;
569 	}
570 	return 1;
571 }
572 
573 void register_transport(struct transport *new)
574 {
575 	struct list_head *ele, *next;
576 	struct eth_init *eth;
577 	void *init;
578 	char *mac = NULL;
579 	int match;
580 
581 	spin_lock(&transports_lock);
582 	BUG_ON(!list_empty(&new->list));
583 	list_add(&new->list, &transports);
584 	spin_unlock(&transports_lock);
585 
586 	list_for_each_safe(ele, next, &eth_cmd_line) {
587 		eth = list_entry(ele, struct eth_init, list);
588 		match = check_transport(new, eth->init, eth->index, &init,
589 					&mac, GFP_KERNEL);
590 		if (!match)
591 			continue;
592 		else if (init != NULL) {
593 			eth_configure(eth->index, init, mac, new, GFP_KERNEL);
594 			kfree(init);
595 		}
596 		list_del(&eth->list);
597 	}
598 }
599 
600 static int eth_setup_common(char *str, int index)
601 {
602 	struct list_head *ele;
603 	struct transport *transport;
604 	void *init;
605 	char *mac = NULL;
606 	int found = 0;
607 
608 	spin_lock(&transports_lock);
609 	list_for_each(ele, &transports) {
610 		transport = list_entry(ele, struct transport, list);
611 	        if (!check_transport(transport, str, index, &init,
612 					&mac, GFP_ATOMIC))
613 			continue;
614 		if (init != NULL) {
615 			eth_configure(index, init, mac, transport, GFP_ATOMIC);
616 			kfree(init);
617 		}
618 		found = 1;
619 		break;
620 	}
621 
622 	spin_unlock(&transports_lock);
623 	return found;
624 }
625 
626 static int __init eth_setup(char *str)
627 {
628 	struct eth_init *new;
629 	char *error;
630 	int n, err;
631 
632 	err = eth_parse(str, &n, &str, &error);
633 	if (err) {
634 		printk(KERN_ERR "eth_setup - Couldn't parse '%s' : %s\n",
635 		       str, error);
636 		return 1;
637 	}
638 
639 	new = memblock_alloc(sizeof(*new), SMP_CACHE_BYTES);
640 	if (!new)
641 		panic("%s: Failed to allocate %zu bytes\n", __func__,
642 		      sizeof(*new));
643 
644 	INIT_LIST_HEAD(&new->list);
645 	new->index = n;
646 	new->init = str;
647 
648 	list_add_tail(&new->list, &eth_cmd_line);
649 	return 1;
650 }
651 
652 __setup("eth", eth_setup);
653 __uml_help(eth_setup,
654 "eth[0-9]+=<transport>,<options>\n"
655 "    Configure a network device.\n\n"
656 );
657 
658 static int net_config(char *str, char **error_out)
659 {
660 	int n, err;
661 
662 	err = eth_parse(str, &n, &str, error_out);
663 	if (err)
664 		return err;
665 
666 	/* This string is broken up and the pieces used by the underlying
667 	 * driver.  So, it is freed only if eth_setup_common fails.
668 	 */
669 	str = kstrdup(str, GFP_KERNEL);
670 	if (str == NULL) {
671 	        *error_out = "net_config failed to strdup string";
672 		return -ENOMEM;
673 	}
674 	err = !eth_setup_common(str, n);
675 	if (err)
676 		kfree(str);
677 	return err;
678 }
679 
680 static int net_id(char **str, int *start_out, int *end_out)
681 {
682 	char *end;
683 	int n;
684 
685 	n = simple_strtoul(*str, &end, 0);
686 	if ((*end != '\0') || (end == *str))
687 		return -1;
688 
689 	*start_out = n;
690 	*end_out = n;
691 	*str = end;
692 	return n;
693 }
694 
695 static int net_remove(int n, char **error_out)
696 {
697 	struct uml_net *device;
698 	struct net_device *dev;
699 	struct uml_net_private *lp;
700 
701 	device = find_device(n);
702 	if (device == NULL)
703 		return -ENODEV;
704 
705 	dev = device->dev;
706 	lp = netdev_priv(dev);
707 	if (lp->fd > 0)
708 		return -EBUSY;
709 	unregister_netdev(dev);
710 	platform_device_unregister(&device->pdev);
711 
712 	return 0;
713 }
714 
715 static struct mc_device net_mc = {
716 	.list		= LIST_HEAD_INIT(net_mc.list),
717 	.name		= "eth",
718 	.config		= net_config,
719 	.get_config	= NULL,
720 	.id		= net_id,
721 	.remove		= net_remove,
722 };
723 
724 #ifdef CONFIG_INET
725 static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
726 			      void *ptr)
727 {
728 	struct in_ifaddr *ifa = ptr;
729 	struct net_device *dev = ifa->ifa_dev->dev;
730 	struct uml_net_private *lp;
731 	void (*proc)(unsigned char *, unsigned char *, void *);
732 	unsigned char addr_buf[4], netmask_buf[4];
733 
734 	if (dev->netdev_ops->ndo_open != uml_net_open)
735 		return NOTIFY_DONE;
736 
737 	lp = netdev_priv(dev);
738 
739 	proc = NULL;
740 	switch (event) {
741 	case NETDEV_UP:
742 		proc = lp->add_address;
743 		break;
744 	case NETDEV_DOWN:
745 		proc = lp->delete_address;
746 		break;
747 	}
748 	if (proc != NULL) {
749 		memcpy(addr_buf, &ifa->ifa_address, sizeof(addr_buf));
750 		memcpy(netmask_buf, &ifa->ifa_mask, sizeof(netmask_buf));
751 		(*proc)(addr_buf, netmask_buf, &lp->user);
752 	}
753 	return NOTIFY_DONE;
754 }
755 
756 /* uml_net_init shouldn't be called twice on two CPUs at the same time */
757 static struct notifier_block uml_inetaddr_notifier = {
758 	.notifier_call		= uml_inetaddr_event,
759 };
760 
761 static void inet_register(void)
762 {
763 	struct list_head *ele;
764 	struct uml_net_private *lp;
765 	struct in_device *ip;
766 	struct in_ifaddr *in;
767 
768 	register_inetaddr_notifier(&uml_inetaddr_notifier);
769 
770 	/* Devices may have been opened already, so the uml_inetaddr_notifier
771 	 * didn't get a chance to run for them.  This fakes it so that
772 	 * addresses which have already been set up get handled properly.
773 	 */
774 	spin_lock(&opened_lock);
775 	list_for_each(ele, &opened) {
776 		lp = list_entry(ele, struct uml_net_private, list);
777 		ip = lp->dev->ip_ptr;
778 		if (ip == NULL)
779 			continue;
780 		in = ip->ifa_list;
781 		while (in != NULL) {
782 			uml_inetaddr_event(NULL, NETDEV_UP, in);
783 			in = in->ifa_next;
784 		}
785 	}
786 	spin_unlock(&opened_lock);
787 }
788 #else
789 static inline void inet_register(void)
790 {
791 }
792 #endif
793 
794 static int uml_net_init(void)
795 {
796 	mconsole_register_dev(&net_mc);
797 	inet_register();
798 	return 0;
799 }
800 
801 __initcall(uml_net_init);
802 
803 static void close_devices(void)
804 {
805 	struct list_head *ele;
806 	struct uml_net_private *lp;
807 
808 	spin_lock(&opened_lock);
809 	list_for_each(ele, &opened) {
810 		lp = list_entry(ele, struct uml_net_private, list);
811 		um_free_irq(lp->dev->irq, lp->dev);
812 		if ((lp->close != NULL) && (lp->fd >= 0))
813 			(*lp->close)(lp->fd, &lp->user);
814 		if (lp->remove != NULL)
815 			(*lp->remove)(&lp->user);
816 	}
817 	spin_unlock(&opened_lock);
818 }
819 
820 __uml_exitcall(close_devices);
821 
822 void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *,
823 					void *),
824 		    void *arg)
825 {
826 	struct net_device *dev = d;
827 	struct in_device *ip = dev->ip_ptr;
828 	struct in_ifaddr *in;
829 	unsigned char address[4], netmask[4];
830 
831 	if (ip == NULL) return;
832 	in = ip->ifa_list;
833 	while (in != NULL) {
834 		memcpy(address, &in->ifa_address, sizeof(address));
835 		memcpy(netmask, &in->ifa_mask, sizeof(netmask));
836 		(*cb)(address, netmask, arg);
837 		in = in->ifa_next;
838 	}
839 }
840 
841 int dev_netmask(void *d, void *m)
842 {
843 	struct net_device *dev = d;
844 	struct in_device *ip = dev->ip_ptr;
845 	struct in_ifaddr *in;
846 	__be32 *mask_out = m;
847 
848 	if (ip == NULL)
849 		return 1;
850 
851 	in = ip->ifa_list;
852 	if (in == NULL)
853 		return 1;
854 
855 	*mask_out = in->ifa_mask;
856 	return 0;
857 }
858 
859 void *get_output_buffer(int *len_out)
860 {
861 	void *ret;
862 
863 	ret = (void *) __get_free_pages(GFP_KERNEL, 0);
864 	if (ret) *len_out = PAGE_SIZE;
865 	else *len_out = 0;
866 	return ret;
867 }
868 
869 void free_output_buffer(void *buffer)
870 {
871 	free_pages((unsigned long) buffer, 0);
872 }
873 
874 int tap_setup_common(char *str, char *type, char **dev_name, char **mac_out,
875 		     char **gate_addr)
876 {
877 	char *remain;
878 
879 	remain = split_if_spec(str, dev_name, mac_out, gate_addr, NULL);
880 	if (remain != NULL) {
881 		printk(KERN_ERR "tap_setup_common - Extra garbage on "
882 		       "specification : '%s'\n", remain);
883 		return 1;
884 	}
885 
886 	return 0;
887 }
888 
889 unsigned short eth_protocol(struct sk_buff *skb)
890 {
891 	return eth_type_trans(skb, skb->dev);
892 }
893