[PATCH] uml: fix net_kern workqueue abuse
[safe/jmp/linux-2.6] / arch / um / drivers / net_kern.c
1 /*
2  * Copyright (C) 2001 Lennert Buytenhek (buytenh@gnu.org) and 
3  * James Leu (jleu@mindspring.net).
4  * Copyright (C) 2001 by various other people who didn't put their name here.
5  * Licensed under the GPL.
6  */
7
8 #include "linux/kernel.h"
9 #include "linux/netdevice.h"
10 #include "linux/rtnetlink.h"
11 #include "linux/skbuff.h"
12 #include "linux/socket.h"
13 #include "linux/spinlock.h"
14 #include "linux/module.h"
15 #include "linux/init.h"
16 #include "linux/etherdevice.h"
17 #include "linux/list.h"
18 #include "linux/inetdevice.h"
19 #include "linux/ctype.h"
20 #include "linux/bootmem.h"
21 #include "linux/ethtool.h"
22 #include "linux/platform_device.h"
23 #include "asm/uaccess.h"
24 #include "user_util.h"
25 #include "kern_util.h"
26 #include "net_kern.h"
27 #include "net_user.h"
28 #include "mconsole_kern.h"
29 #include "init.h"
30 #include "irq_user.h"
31 #include "irq_kern.h"
32
33 static inline void set_ether_mac(struct net_device *dev, unsigned char *addr)
34 {
35         memcpy(dev->dev_addr, addr, ETH_ALEN);
36 }
37
38 #define DRIVER_NAME "uml-netdev"
39
40 static DEFINE_SPINLOCK(opened_lock);
41 static LIST_HEAD(opened);
42
43 static int uml_net_rx(struct net_device *dev)
44 {
45         struct uml_net_private *lp = dev->priv;
46         int pkt_len;
47         struct sk_buff *skb;
48
49         /* If we can't allocate memory, try again next round. */
50         skb = dev_alloc_skb(dev->mtu);
51         if (skb == NULL) {
52                 lp->stats.rx_dropped++;
53                 return 0;
54         }
55
56         skb->dev = dev;
57         skb_put(skb, dev->mtu);
58         skb->mac.raw = skb->data;
59         pkt_len = (*lp->read)(lp->fd, &skb, lp);
60
61         if (pkt_len > 0) {
62                 skb_trim(skb, pkt_len);
63                 skb->protocol = (*lp->protocol)(skb);
64                 netif_rx(skb);
65
66                 lp->stats.rx_bytes += skb->len;
67                 lp->stats.rx_packets++;
68                 return pkt_len;
69         }
70
71         kfree_skb(skb);
72         return pkt_len;
73 }
74
75 static void uml_dev_close(struct work_struct *work)
76 {
77         struct uml_net_private *lp =
78                 container_of(work, struct uml_net_private, work);
79         dev_close(lp->dev);
80 }
81
82 irqreturn_t uml_net_interrupt(int irq, void *dev_id)
83 {
84         struct net_device *dev = dev_id;
85         struct uml_net_private *lp = dev->priv;
86         int err;
87
88         if(!netif_running(dev))
89                 return(IRQ_NONE);
90
91         spin_lock(&lp->lock);
92         while((err = uml_net_rx(dev)) > 0) ;
93         if(err < 0) {
94                 printk(KERN_ERR 
95                        "Device '%s' read returned %d, shutting it down\n", 
96                        dev->name, err);
97                 /* dev_close can't be called in interrupt context, and takes
98                  * again lp->lock.
99                  * And dev_close() can be safely called multiple times on the
100                  * same device, since it tests for (dev->flags & IFF_UP). So
101                  * there's no harm in delaying the device shutdown.
102                  * Furthermore, the workqueue will not re-enqueue an already
103                  * enqueued work item. */
104                 schedule_work(&lp->work);
105                 goto out;
106         }
107         reactivate_fd(lp->fd, UM_ETH_IRQ);
108
109 out:
110         spin_unlock(&lp->lock);
111         return(IRQ_HANDLED);
112 }
113
114 static int uml_net_open(struct net_device *dev)
115 {
116         struct uml_net_private *lp = dev->priv;
117         int err;
118
119         if(lp->fd >= 0){
120                 err = -ENXIO;
121                 goto out;
122         }
123
124         lp->fd = (*lp->open)(&lp->user);
125         if(lp->fd < 0){
126                 err = lp->fd;
127                 goto out;
128         }
129
130         err = um_request_irq(dev->irq, lp->fd, IRQ_READ, uml_net_interrupt,
131                              IRQF_DISABLED | IRQF_SHARED, dev->name, dev);
132         if(err != 0){
133                 printk(KERN_ERR "uml_net_open: failed to get irq(%d)\n", err);
134                 err = -ENETUNREACH;
135                 goto out_close;
136         }
137
138         lp->tl.data = (unsigned long) &lp->user;
139         netif_start_queue(dev);
140
141         /* clear buffer - it can happen that the host side of the interface
142          * is full when we get here.  In this case, new data is never queued,
143          * SIGIOs never arrive, and the net never works.
144          */
145         while((err = uml_net_rx(dev)) > 0) ;
146
147         spin_lock(&opened_lock);
148         list_add(&lp->list, &opened);
149         spin_unlock(&opened_lock);
150
151         return 0;
152 out_close:
153         if(lp->close != NULL) (*lp->close)(lp->fd, &lp->user);
154         lp->fd = -1;
155 out:
156         return err;
157 }
158
159 static int uml_net_close(struct net_device *dev)
160 {
161         struct uml_net_private *lp = dev->priv;
162         
163         netif_stop_queue(dev);
164
165         free_irq(dev->irq, dev);
166         if(lp->close != NULL)
167                 (*lp->close)(lp->fd, &lp->user);
168         lp->fd = -1;
169
170         spin_lock(&opened_lock);
171         list_del(&lp->list);
172         spin_unlock(&opened_lock);
173
174         return 0;
175 }
176
177 static int uml_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
178 {
179         struct uml_net_private *lp = dev->priv;
180         unsigned long flags;
181         int len;
182
183         netif_stop_queue(dev);
184
185         spin_lock_irqsave(&lp->lock, flags);
186
187         len = (*lp->write)(lp->fd, &skb, lp);
188
189         if(len == skb->len) {
190                 lp->stats.tx_packets++;
191                 lp->stats.tx_bytes += skb->len;
192                 dev->trans_start = jiffies;
193                 netif_start_queue(dev);
194
195                 /* this is normally done in the interrupt when tx finishes */
196                 netif_wake_queue(dev);
197         } 
198         else if(len == 0){
199                 netif_start_queue(dev);
200                 lp->stats.tx_dropped++;
201         }
202         else {
203                 netif_start_queue(dev);
204                 printk(KERN_ERR "uml_net_start_xmit: failed(%d)\n", len);
205         }
206
207         spin_unlock_irqrestore(&lp->lock, flags);
208
209         dev_kfree_skb(skb);
210
211         return 0;
212 }
213
214 static struct net_device_stats *uml_net_get_stats(struct net_device *dev)
215 {
216         struct uml_net_private *lp = dev->priv;
217         return &lp->stats;
218 }
219
220 static void uml_net_set_multicast_list(struct net_device *dev)
221 {
222         if (dev->flags & IFF_PROMISC) return;
223         else if (dev->mc_count) dev->flags |= IFF_ALLMULTI;
224         else dev->flags &= ~IFF_ALLMULTI;
225 }
226
227 static void uml_net_tx_timeout(struct net_device *dev)
228 {
229         dev->trans_start = jiffies;
230         netif_wake_queue(dev);
231 }
232
233 static int uml_net_set_mac(struct net_device *dev, void *addr)
234 {
235         struct uml_net_private *lp = dev->priv;
236         struct sockaddr *hwaddr = addr;
237
238         spin_lock_irq(&lp->lock);
239         set_ether_mac(dev, hwaddr->sa_data);
240         spin_unlock_irq(&lp->lock);
241
242         return(0);
243 }
244
245 static int uml_net_change_mtu(struct net_device *dev, int new_mtu)
246 {
247         struct uml_net_private *lp = dev->priv;
248         int err = 0;
249
250         spin_lock_irq(&lp->lock);
251
252         new_mtu = (*lp->set_mtu)(new_mtu, &lp->user);
253         if(new_mtu < 0){
254                 err = new_mtu;
255                 goto out;
256         }
257
258         dev->mtu = new_mtu;
259
260  out:
261         spin_unlock_irq(&lp->lock);
262         return err;
263 }
264
265 static void uml_net_get_drvinfo(struct net_device *dev,
266                                 struct ethtool_drvinfo *info)
267 {
268         strcpy(info->driver, DRIVER_NAME);
269         strcpy(info->version, "42");
270 }
271
272 static struct ethtool_ops uml_net_ethtool_ops = {
273         .get_drvinfo    = uml_net_get_drvinfo,
274         .get_link       = ethtool_op_get_link,
275 };
276
277 void uml_net_user_timer_expire(unsigned long _conn)
278 {
279 #ifdef undef
280         struct connection *conn = (struct connection *)_conn;
281
282         dprintk(KERN_INFO "uml_net_user_timer_expire [%p]\n", conn);
283         do_connect(conn);
284 #endif
285 }
286
287 static void setup_etheraddr(char *str, unsigned char *addr)
288 {
289         char *end;
290         int i;
291
292         if(str == NULL)
293                 goto random;
294
295         for(i=0;i<6;i++){
296                 addr[i] = simple_strtoul(str, &end, 16);
297                 if((end == str) ||
298                    ((*end != ':') && (*end != ',') && (*end != '\0'))){
299                         printk(KERN_ERR
300                                "setup_etheraddr: failed to parse '%s' "
301                                "as an ethernet address\n", str);
302                         goto random;
303                 }
304                 str = end + 1;
305         }
306         if(addr[0] & 1){
307                 printk(KERN_ERR
308                        "Attempt to assign a broadcast ethernet address to a "
309                        "device disallowed\n");
310                 goto random;
311         }
312         return;
313
314 random:
315         random_ether_addr(addr);
316 }
317
318 static DEFINE_SPINLOCK(devices_lock);
319 static LIST_HEAD(devices);
320
321 static struct platform_driver uml_net_driver = {
322         .driver = {
323                 .name  = DRIVER_NAME,
324         },
325 };
326 static int driver_registered;
327
328 static int eth_configure(int n, void *init, char *mac,
329                          struct transport *transport)
330 {
331         struct uml_net *device;
332         struct net_device *dev;
333         struct uml_net_private *lp;
334         int save, err, size;
335
336         size = transport->private_size + sizeof(struct uml_net_private) + 
337                 sizeof(((struct uml_net_private *) 0)->user);
338
339         device = kzalloc(sizeof(*device), GFP_KERNEL);
340         if (device == NULL) {
341                 printk(KERN_ERR "eth_configure failed to allocate uml_net\n");
342                 return(1);
343         }
344
345         INIT_LIST_HEAD(&device->list);
346         device->index = n;
347
348         spin_lock(&devices_lock);
349         list_add(&device->list, &devices);
350         spin_unlock(&devices_lock);
351
352         setup_etheraddr(mac, device->mac);
353
354         printk(KERN_INFO "Netdevice %d ", n);
355         printk("(%02x:%02x:%02x:%02x:%02x:%02x) ",
356                device->mac[0], device->mac[1],
357                device->mac[2], device->mac[3],
358                device->mac[4], device->mac[5]);
359         printk(": ");
360         dev = alloc_etherdev(size);
361         if (dev == NULL) {
362                 printk(KERN_ERR "eth_configure: failed to allocate device\n");
363                 return 1;
364         }
365
366         lp = dev->priv;
367         /* This points to the transport private data. It's still clear, but we
368          * must memset it to 0 *now*. Let's help the drivers. */
369         memset(lp, 0, size);
370         INIT_WORK(&lp->work, uml_dev_close);
371
372         /* sysfs register */
373         if (!driver_registered) {
374                 platform_driver_register(&uml_net_driver);
375                 driver_registered = 1;
376         }
377         device->pdev.id = n;
378         device->pdev.name = DRIVER_NAME;
379         platform_device_register(&device->pdev);
380         SET_NETDEV_DEV(dev,&device->pdev.dev);
381
382         /* If this name ends up conflicting with an existing registered
383          * netdevice, that is OK, register_netdev{,ice}() will notice this
384          * and fail.
385          */
386         snprintf(dev->name, sizeof(dev->name), "eth%d", n);
387         device->dev = dev;
388
389         (*transport->kern->init)(dev, init);
390
391         dev->mtu = transport->user->max_packet;
392         dev->open = uml_net_open;
393         dev->hard_start_xmit = uml_net_start_xmit;
394         dev->stop = uml_net_close;
395         dev->get_stats = uml_net_get_stats;
396         dev->set_multicast_list = uml_net_set_multicast_list;
397         dev->tx_timeout = uml_net_tx_timeout;
398         dev->set_mac_address = uml_net_set_mac;
399         dev->change_mtu = uml_net_change_mtu;
400         dev->ethtool_ops = &uml_net_ethtool_ops;
401         dev->watchdog_timeo = (HZ >> 1);
402         dev->irq = UM_ETH_IRQ;
403
404         rtnl_lock();
405         err = register_netdevice(dev);
406         rtnl_unlock();
407         if (err) {
408                 device->dev = NULL;
409                 /* XXX: should we call ->remove() here? */
410                 free_netdev(dev);
411                 return 1;
412         }
413
414         /* lp.user is the first four bytes of the transport data, which
415          * has already been initialized.  This structure assignment will
416          * overwrite that, so we make sure that .user gets overwritten with
417          * what it already has.
418          */
419         save = lp->user[0];
420         *lp = ((struct uml_net_private)
421                 { .list                 = LIST_HEAD_INIT(lp->list),
422                   .dev                  = dev,
423                   .fd                   = -1,
424                   .mac                  = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0},
425                   .protocol             = transport->kern->protocol,
426                   .open                 = transport->user->open,
427                   .close                = transport->user->close,
428                   .remove               = transport->user->remove,
429                   .read                 = transport->kern->read,
430                   .write                = transport->kern->write,
431                   .add_address          = transport->user->add_address,
432                   .delete_address       = transport->user->delete_address,
433                   .set_mtu              = transport->user->set_mtu,
434                   .user                 = { save } });
435
436         init_timer(&lp->tl);
437         spin_lock_init(&lp->lock);
438         lp->tl.function = uml_net_user_timer_expire;
439         memcpy(lp->mac, device->mac, sizeof(lp->mac));
440
441         if (transport->user->init) 
442                 (*transport->user->init)(&lp->user, dev);
443
444         set_ether_mac(dev, device->mac);
445
446         return 0;
447 }
448
449 static struct uml_net *find_device(int n)
450 {
451         struct uml_net *device;
452         struct list_head *ele;
453
454         spin_lock(&devices_lock);
455         list_for_each(ele, &devices){
456                 device = list_entry(ele, struct uml_net, list);
457                 if(device->index == n)
458                         goto out;
459         }
460         device = NULL;
461  out:
462         spin_unlock(&devices_lock);
463         return(device);
464 }
465
466 static int eth_parse(char *str, int *index_out, char **str_out)
467 {
468         char *end;
469         int n;
470
471         n = simple_strtoul(str, &end, 0);
472         if(end == str){
473                 printk(KERN_ERR "eth_setup: Failed to parse '%s'\n", str);
474                 return(1);
475         }
476         if(n < 0){
477                 printk(KERN_ERR "eth_setup: device %d is negative\n", n);
478                 return(1);
479         }
480         str = end;
481         if(*str != '='){
482                 printk(KERN_ERR 
483                        "eth_setup: expected '=' after device number\n");
484                 return(1);
485         }
486         str++;
487         if(find_device(n)){
488                 printk(KERN_ERR "eth_setup: Device %d already configured\n",
489                        n);
490                 return(1);
491         }
492         if(index_out) *index_out = n;
493         *str_out = str;
494         return(0);
495 }
496
497 struct eth_init {
498         struct list_head list;
499         char *init;
500         int index;
501 };
502
503 /* Filled in at boot time.  Will need locking if the transports become
504  * modular.
505  */
506 struct list_head transports = LIST_HEAD_INIT(transports);
507
508 /* Filled in during early boot */
509 struct list_head eth_cmd_line = LIST_HEAD_INIT(eth_cmd_line);
510
511 static int check_transport(struct transport *transport, char *eth, int n,
512                            void **init_out, char **mac_out)
513 {
514         int len;
515
516         len = strlen(transport->name);
517         if(strncmp(eth, transport->name, len))
518                 return(0);
519
520         eth += len;
521         if(*eth == ',')
522                 eth++;
523         else if(*eth != '\0')
524                 return(0);
525
526         *init_out = kmalloc(transport->setup_size, GFP_KERNEL);
527         if(*init_out == NULL)
528                 return(1);
529
530         if(!transport->setup(eth, mac_out, *init_out)){
531                 kfree(*init_out);
532                 *init_out = NULL;
533         }
534         return(1);
535 }
536
537 void register_transport(struct transport *new)
538 {
539         struct list_head *ele, *next;
540         struct eth_init *eth;
541         void *init;
542         char *mac = NULL;
543         int match;
544
545         list_add(&new->list, &transports);
546
547         list_for_each_safe(ele, next, &eth_cmd_line){
548                 eth = list_entry(ele, struct eth_init, list);
549                 match = check_transport(new, eth->init, eth->index, &init,
550                                         &mac);
551                 if(!match)
552                         continue;
553                 else if(init != NULL){
554                         eth_configure(eth->index, init, mac, new);
555                         kfree(init);
556                 }
557                 list_del(&eth->list);
558         }
559 }
560
561 static int eth_setup_common(char *str, int index)
562 {
563         struct list_head *ele;
564         struct transport *transport;
565         void *init;
566         char *mac = NULL;
567
568         list_for_each(ele, &transports){
569                 transport = list_entry(ele, struct transport, list);
570                 if(!check_transport(transport, str, index, &init, &mac))
571                         continue;
572                 if(init != NULL){
573                         eth_configure(index, init, mac, transport);
574                         kfree(init);
575                 }
576                 return(1);
577         }
578         return(0);
579 }
580
581 static int eth_setup(char *str)
582 {
583         struct eth_init *new;
584         int n, err;
585
586         err = eth_parse(str, &n, &str);
587         if(err)
588                 return 1;
589
590         new = alloc_bootmem(sizeof(*new));
591         if (new == NULL){
592                 printk("eth_init : alloc_bootmem failed\n");
593                 return 1;
594         }
595
596         INIT_LIST_HEAD(&new->list);
597         new->index = n;
598         new->init = str;
599
600         list_add_tail(&new->list, &eth_cmd_line);
601         return 1;
602 }
603
604 __setup("eth", eth_setup);
605 __uml_help(eth_setup,
606 "eth[0-9]+=<transport>,<options>\n"
607 "    Configure a network device.\n\n"
608 );
609
610 #if 0
611 static int eth_init(void)
612 {
613         struct list_head *ele, *next;
614         struct eth_init *eth;
615
616         list_for_each_safe(ele, next, &eth_cmd_line){
617                 eth = list_entry(ele, struct eth_init, list);
618
619                 if(eth_setup_common(eth->init, eth->index))
620                         list_del(&eth->list);
621         }
622         
623         return(1);
624 }
625 __initcall(eth_init);
626 #endif
627
628 static int net_config(char *str)
629 {
630         int n, err;
631
632         err = eth_parse(str, &n, &str);
633         if(err) return(err);
634
635         str = kstrdup(str, GFP_KERNEL);
636         if(str == NULL){
637                 printk(KERN_ERR "net_config failed to strdup string\n");
638                 return(-1);
639         }
640         err = !eth_setup_common(str, n);
641         if(err) 
642                 kfree(str);
643         return(err);
644 }
645
646 static int net_id(char **str, int *start_out, int *end_out)
647 {
648         char *end;
649         int n;
650
651         n = simple_strtoul(*str, &end, 0);
652         if((*end != '\0') || (end == *str))
653                 return -1;
654
655         *start_out = n;
656         *end_out = n;
657         *str = end;
658         return n;
659 }
660
661 static int net_remove(int n)
662 {
663         struct uml_net *device;
664         struct net_device *dev;
665         struct uml_net_private *lp;
666
667         device = find_device(n);
668         if(device == NULL)
669                 return -ENODEV;
670
671         dev = device->dev;
672         lp = dev->priv;
673         if(lp->fd > 0)
674                 return -EBUSY;
675         if(lp->remove != NULL) (*lp->remove)(&lp->user);
676         unregister_netdev(dev);
677         platform_device_unregister(&device->pdev);
678
679         list_del(&device->list);
680         kfree(device);
681         free_netdev(dev);
682         return 0;
683 }
684
685 static struct mc_device net_mc = {
686         .name           = "eth",
687         .config         = net_config,
688         .get_config     = NULL,
689         .id             = net_id,
690         .remove         = net_remove,
691 };
692
693 static int uml_inetaddr_event(struct notifier_block *this, unsigned long event,
694                               void *ptr)
695 {
696         struct in_ifaddr *ifa = ptr;
697         struct net_device *dev = ifa->ifa_dev->dev;
698         struct uml_net_private *lp;
699         void (*proc)(unsigned char *, unsigned char *, void *);
700         unsigned char addr_buf[4], netmask_buf[4];
701
702         if(dev->open != uml_net_open) return(NOTIFY_DONE);
703
704         lp = dev->priv;
705
706         proc = NULL;
707         switch (event){
708         case NETDEV_UP:
709                 proc = lp->add_address;
710                 break;
711         case NETDEV_DOWN:
712                 proc = lp->delete_address;
713                 break;
714         }
715         if(proc != NULL){
716                 memcpy(addr_buf, &ifa->ifa_address, sizeof(addr_buf));
717                 memcpy(netmask_buf, &ifa->ifa_mask, sizeof(netmask_buf));
718                 (*proc)(addr_buf, netmask_buf, &lp->user);
719         }
720         return(NOTIFY_DONE);
721 }
722
723 struct notifier_block uml_inetaddr_notifier = {
724         .notifier_call          = uml_inetaddr_event,
725 };
726
727 static int uml_net_init(void)
728 {
729         struct list_head *ele;
730         struct uml_net_private *lp;     
731         struct in_device *ip;
732         struct in_ifaddr *in;
733
734         mconsole_register_dev(&net_mc);
735         register_inetaddr_notifier(&uml_inetaddr_notifier);
736
737         /* Devices may have been opened already, so the uml_inetaddr_notifier
738          * didn't get a chance to run for them.  This fakes it so that
739          * addresses which have already been set up get handled properly.
740          */
741         list_for_each(ele, &opened){
742                 lp = list_entry(ele, struct uml_net_private, list);
743                 ip = lp->dev->ip_ptr;
744                 if(ip == NULL) continue;
745                 in = ip->ifa_list;
746                 while(in != NULL){
747                         uml_inetaddr_event(NULL, NETDEV_UP, in);
748                         in = in->ifa_next;
749                 }
750         }       
751
752         return(0);
753 }
754
755 __initcall(uml_net_init);
756
757 static void close_devices(void)
758 {
759         struct list_head *ele;
760         struct uml_net_private *lp;
761
762         list_for_each(ele, &opened){
763                 lp = list_entry(ele, struct uml_net_private, list);
764                 free_irq(lp->dev->irq, lp->dev);
765                 if((lp->close != NULL) && (lp->fd >= 0))
766                         (*lp->close)(lp->fd, &lp->user);
767                 if(lp->remove != NULL) (*lp->remove)(&lp->user);
768         }
769 }
770
771 __uml_exitcall(close_devices);
772
773 struct sk_buff *ether_adjust_skb(struct sk_buff *skb, int extra)
774 {
775         if((skb != NULL) && (skb_tailroom(skb) < extra)){
776                 struct sk_buff *skb2;
777
778                 skb2 = skb_copy_expand(skb, 0, extra, GFP_ATOMIC);
779                 dev_kfree_skb(skb);
780                 skb = skb2;
781         }
782         if(skb != NULL) skb_put(skb, extra);
783         return(skb);
784 }
785
786 void iter_addresses(void *d, void (*cb)(unsigned char *, unsigned char *, 
787                                         void *), 
788                     void *arg)
789 {
790         struct net_device *dev = d;
791         struct in_device *ip = dev->ip_ptr;
792         struct in_ifaddr *in;
793         unsigned char address[4], netmask[4];
794
795         if(ip == NULL) return;
796         in = ip->ifa_list;
797         while(in != NULL){
798                 memcpy(address, &in->ifa_address, sizeof(address));
799                 memcpy(netmask, &in->ifa_mask, sizeof(netmask));
800                 (*cb)(address, netmask, arg);
801                 in = in->ifa_next;
802         }
803 }
804
805 int dev_netmask(void *d, void *m)
806 {
807         struct net_device *dev = d;
808         struct in_device *ip = dev->ip_ptr;
809         struct in_ifaddr *in;
810         __be32 *mask_out = m;
811
812         if(ip == NULL) 
813                 return(1);
814
815         in = ip->ifa_list;
816         if(in == NULL) 
817                 return(1);
818
819         *mask_out = in->ifa_mask;
820         return(0);
821 }
822
823 void *get_output_buffer(int *len_out)
824 {
825         void *ret;
826
827         ret = (void *) __get_free_pages(GFP_KERNEL, 0);
828         if(ret) *len_out = PAGE_SIZE;
829         else *len_out = 0;
830         return(ret);
831 }
832
833 void free_output_buffer(void *buffer)
834 {
835         free_pages((unsigned long) buffer, 0);
836 }
837
838 int tap_setup_common(char *str, char *type, char **dev_name, char **mac_out, 
839                      char **gate_addr)
840 {
841         char *remain;
842
843         remain = split_if_spec(str, dev_name, mac_out, gate_addr, NULL);
844         if(remain != NULL){
845                 printk("tap_setup_common - Extra garbage on specification : "
846                        "'%s'\n", remain);
847                 return(1);
848         }
849
850         return(0);
851 }
852
853 unsigned short eth_protocol(struct sk_buff *skb)
854 {
855         return(eth_type_trans(skb, skb->dev));
856 }
857
858 /*
859  * Overrides for Emacs so that we follow Linus's tabbing style.
860  * Emacs will notice this stuff at the end of the file and automatically
861  * adjust the settings for this buffer only.  This must remain at the end
862  * of the file.
863  * ---------------------------------------------------------------------------
864  * Local variables:
865  * c-file-style: "linux"
866  * End:
867  */