ip: fix mc_loop checks for tunnels with multicast outer addresses
[linux-2.6.git] / net / wanrouter / wanmain.c
1 /*****************************************************************************
2 * wanmain.c     WAN Multiprotocol Router Module. Main code.
3 *
4 *               This module is completely hardware-independent and provides
5 *               the following common services for the WAN Link Drivers:
6 *                o WAN device management (registering, unregistering)
7 *                o Network interface management
8 *                o Physical connection management (dial-up, incoming calls)
9 *                o Logical connection management (switched virtual circuits)
10 *                o Protocol encapsulation/decapsulation
11 *
12 * Author:       Gideon Hack
13 *
14 * Copyright:    (c) 1995-1999 Sangoma Technologies Inc.
15 *
16 *               This program is free software; you can redistribute it and/or
17 *               modify it under the terms of the GNU General Public License
18 *               as published by the Free Software Foundation; either version
19 *               2 of the License, or (at your option) any later version.
20 * ============================================================================
21 * Nov 24, 2000  Nenad Corbic    Updated for 2.4.X kernels
22 * Nov 07, 2000  Nenad Corbic    Fixed the Mulit-Port PPP for kernels 2.2.16 and
23 *                               greater.
24 * Aug 2,  2000  Nenad Corbic    Block the Multi-Port PPP from running on
25 *                               kernels 2.2.16 or greater.  The SyncPPP
26 *                               has changed.
27 * Jul 13, 2000  Nenad Corbic    Added SyncPPP support
28 *                               Added extra debugging in device_setup().
29 * Oct 01, 1999  Gideon Hack     Update for s514 PCI card
30 * Dec 27, 1996  Gene Kozin      Initial version (based on Sangoma's WANPIPE)
31 * Jan 16, 1997  Gene Kozin      router_devlist made public
32 * Jan 31, 1997  Alan Cox        Hacked it about a bit for 2.1
33 * Jun 27, 1997  Alan Cox        realigned with vendor code
34 * Oct 15, 1997  Farhan Thawar   changed wan_encapsulate to add a pad byte of 0
35 * Apr 20, 1998  Alan Cox        Fixed 2.1 symbols
36 * May 17, 1998  K. Baranowski   Fixed SNAP encapsulation in wan_encapsulate
37 * Dec 15, 1998  Arnaldo Melo    support for firmwares of up to 128000 bytes
38 *                               check wandev->setup return value
39 * Dec 22, 1998  Arnaldo Melo    vmalloc/vfree used in device_setup to allocate
40 *                               kernel memory and copy configuration data to
41 *                               kernel space (for big firmwares)
42 * Jun 02, 1999  Gideon Hack     Updates for Linux 2.0.X and 2.2.X kernels.
43 *****************************************************************************/
44
45 #include <linux/stddef.h>       /* offsetof(), etc. */
46 #include <linux/capability.h>
47 #include <linux/errno.h>        /* return codes */
48 #include <linux/kernel.h>
49 #include <linux/module.h>       /* support for loadable modules */
50 #include <linux/slab.h>         /* kmalloc(), kfree() */
51 #include <linux/smp_lock.h>
52 #include <linux/mm.h>
53 #include <linux/string.h>       /* inline mem*, str* functions */
54
55 #include <asm/byteorder.h>      /* htons(), etc. */
56 #include <linux/wanrouter.h>    /* WAN router API definitions */
57
58 #include <linux/vmalloc.h>      /* vmalloc, vfree */
59 #include <asm/uaccess.h>        /* copy_to/from_user */
60 #include <linux/init.h>         /* __initfunc et al. */
61
62 #define KMEM_SAFETYZONE 8
63
64 #define DEV_TO_SLAVE(dev)       (*((struct net_device **)netdev_priv(dev)))
65
66 /*
67  *      Function Prototypes
68  */
69
70 /*
71  *      WAN device IOCTL handlers
72  */
73
74 static int wanrouter_device_setup(struct wan_device *wandev,
75                                   wandev_conf_t __user *u_conf);
76 static int wanrouter_device_stat(struct wan_device *wandev,
77                                  wandev_stat_t __user *u_stat);
78 static int wanrouter_device_shutdown(struct wan_device *wandev);
79 static int wanrouter_device_new_if(struct wan_device *wandev,
80                                    wanif_conf_t __user *u_conf);
81 static int wanrouter_device_del_if(struct wan_device *wandev,
82                                    char __user *u_name);
83
84 /*
85  *      Miscellaneous
86  */
87
88 static struct wan_device *wanrouter_find_device(char *name);
89 static int wanrouter_delete_interface(struct wan_device *wandev, char *name);
90 static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
91         __acquires(lock);
92 static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
93         __releases(lock);
94
95
96
97 /*
98  *      Global Data
99  */
100
101 static char wanrouter_fullname[]  = "Sangoma WANPIPE Router";
102 static char wanrouter_copyright[] = "(c) 1995-2000 Sangoma Technologies Inc.";
103 static char wanrouter_modname[] = ROUTER_NAME; /* short module name */
104 struct wan_device* wanrouter_router_devlist; /* list of registered devices */
105
106 /*
107  *      Organize Unique Identifiers for encapsulation/decapsulation
108  */
109
110 #if 0
111 static unsigned char wanrouter_oui_ether[] = { 0x00, 0x00, 0x00 };
112 static unsigned char wanrouter_oui_802_2[] = { 0x00, 0x80, 0xC2 };
113 #endif
114
115 static int __init wanrouter_init(void)
116 {
117         int err;
118
119         printk(KERN_INFO "%s v%u.%u %s\n",
120                wanrouter_fullname, ROUTER_VERSION, ROUTER_RELEASE,
121                wanrouter_copyright);
122
123         err = wanrouter_proc_init();
124         if (err)
125                 printk(KERN_INFO "%s: can't create entry in proc filesystem!\n",
126                        wanrouter_modname);
127
128         return err;
129 }
130
131 static void __exit wanrouter_cleanup (void)
132 {
133         wanrouter_proc_cleanup();
134 }
135
136 /*
137  * This is just plain dumb.  We should move the bugger to drivers/net/wan,
138  * slap it first in directory and make it module_init().  The only reason
139  * for subsys_initcall() here is that net goes after drivers (why, BTW?)
140  */
141 subsys_initcall(wanrouter_init);
142 module_exit(wanrouter_cleanup);
143
144 /*
145  *      Kernel APIs
146  */
147
148 /*
149  *      Register WAN device.
150  *      o verify device credentials
151  *      o create an entry for the device in the /proc/net/router directory
152  *      o initialize internally maintained fields of the wan_device structure
153  *      o link device data space to a singly-linked list
154  *      o if it's the first device, then start kernel 'thread'
155  *      o increment module use count
156  *
157  *      Return:
158  *      0       Ok
159  *      < 0     error.
160  *
161  *      Context:        process
162  */
163
164
165 int register_wan_device(struct wan_device *wandev)
166 {
167         int err, namelen;
168
169         if ((wandev == NULL) || (wandev->magic != ROUTER_MAGIC) ||
170             (wandev->name == NULL))
171                 return -EINVAL;
172
173         namelen = strlen(wandev->name);
174         if (!namelen || (namelen > WAN_DRVNAME_SZ))
175                 return -EINVAL;
176
177         if (wanrouter_find_device(wandev->name))
178                 return -EEXIST;
179
180 #ifdef WANDEBUG
181         printk(KERN_INFO "%s: registering WAN device %s\n",
182                wanrouter_modname, wandev->name);
183 #endif
184
185         /*
186          *      Register /proc directory entry
187          */
188         err = wanrouter_proc_add(wandev);
189         if (err) {
190                 printk(KERN_INFO
191                         "%s: can't create /proc/net/router/%s entry!\n",
192                         wanrouter_modname, wandev->name);
193                 return err;
194         }
195
196         /*
197          *      Initialize fields of the wan_device structure maintained by the
198          *      router and update local data.
199          */
200
201         wandev->ndev = 0;
202         wandev->dev  = NULL;
203         wandev->next = wanrouter_router_devlist;
204         wanrouter_router_devlist = wandev;
205         return 0;
206 }
207
208 /*
209  *      Unregister WAN device.
210  *      o shut down device
211  *      o unlink device data space from the linked list
212  *      o delete device entry in the /proc/net/router directory
213  *      o decrement module use count
214  *
215  *      Return:         0       Ok
216  *                      <0      error.
217  *      Context:        process
218  */
219
220
221 int unregister_wan_device(char *name)
222 {
223         struct wan_device *wandev, *prev;
224
225         if (name == NULL)
226                 return -EINVAL;
227
228         for (wandev = wanrouter_router_devlist, prev = NULL;
229                 wandev && strcmp(wandev->name, name);
230                 prev = wandev, wandev = wandev->next)
231                 ;
232         if (wandev == NULL)
233                 return -ENODEV;
234
235 #ifdef WANDEBUG
236         printk(KERN_INFO "%s: unregistering WAN device %s\n",
237                wanrouter_modname, name);
238 #endif
239
240         if (wandev->state != WAN_UNCONFIGURED)
241                 wanrouter_device_shutdown(wandev);
242
243         if (prev)
244                 prev->next = wandev->next;
245         else
246                 wanrouter_router_devlist = wandev->next;
247
248         wanrouter_proc_delete(wandev);
249         return 0;
250 }
251
252 #if 0
253
254 /*
255  *      Encapsulate packet.
256  *
257  *      Return: encapsulation header size
258  *              < 0     - unsupported Ethertype
259  *
260  *      Notes:
261  *      1. This function may be called on interrupt context.
262  */
263
264
265 int wanrouter_encapsulate(struct sk_buff *skb, struct net_device *dev,
266                           unsigned short type)
267 {
268         int hdr_len = 0;
269
270         switch (type) {
271         case ETH_P_IP:          /* IP datagram encapsulation */
272                 hdr_len += 1;
273                 skb_push(skb, 1);
274                 skb->data[0] = NLPID_IP;
275                 break;
276
277         case ETH_P_IPX:         /* SNAP encapsulation */
278         case ETH_P_ARP:
279                 hdr_len += 7;
280                 skb_push(skb, 7);
281                 skb->data[0] = 0;
282                 skb->data[1] = NLPID_SNAP;
283                 skb_copy_to_linear_data_offset(skb, 2, wanrouter_oui_ether,
284                                                sizeof(wanrouter_oui_ether));
285                 *((unsigned short*)&skb->data[5]) = htons(type);
286                 break;
287
288         default:                /* Unknown packet type */
289                 printk(KERN_INFO
290                         "%s: unsupported Ethertype 0x%04X on interface %s!\n",
291                         wanrouter_modname, type, dev->name);
292                 hdr_len = -EINVAL;
293         }
294         return hdr_len;
295 }
296
297
298 /*
299  *      Decapsulate packet.
300  *
301  *      Return: Ethertype (in network order)
302  *                      0       unknown encapsulation
303  *
304  *      Notes:
305  *      1. This function may be called on interrupt context.
306  */
307
308
309 __be16 wanrouter_type_trans(struct sk_buff *skb, struct net_device *dev)
310 {
311         int cnt = skb->data[0] ? 0 : 1; /* there may be a pad present */
312         __be16 ethertype;
313
314         switch (skb->data[cnt]) {
315         case NLPID_IP:          /* IP datagramm */
316                 ethertype = htons(ETH_P_IP);
317                 cnt += 1;
318                 break;
319
320         case NLPID_SNAP:        /* SNAP encapsulation */
321                 if (memcmp(&skb->data[cnt + 1], wanrouter_oui_ether,
322                            sizeof(wanrouter_oui_ether))){
323                         printk(KERN_INFO
324                                 "%s: unsupported SNAP OUI %02X-%02X-%02X "
325                                 "on interface %s!\n", wanrouter_modname,
326                                 skb->data[cnt+1], skb->data[cnt+2],
327                                 skb->data[cnt+3], dev->name);
328                         return 0;
329                 }
330                 ethertype = *((__be16*)&skb->data[cnt+4]);
331                 cnt += 6;
332                 break;
333
334         /* add other protocols, e.g. CLNP, ESIS, ISIS, if needed */
335
336         default:
337                 printk(KERN_INFO
338                         "%s: unsupported NLPID 0x%02X on interface %s!\n",
339                         wanrouter_modname, skb->data[cnt], dev->name);
340                 return 0;
341         }
342         skb->protocol = ethertype;
343         skb->pkt_type = PACKET_HOST;    /*      Physically point to point */
344         skb_pull(skb, cnt);
345         skb_reset_mac_header(skb);
346         return ethertype;
347 }
348
349 #endif  /*  0  */
350
351 /*
352  *      WAN device IOCTL.
353  *      o find WAN device associated with this node
354  *      o execute requested action or pass command to the device driver
355  */
356
357 long wanrouter_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
358 {
359         struct inode *inode = file->f_path.dentry->d_inode;
360         int err = 0;
361         struct proc_dir_entry *dent;
362         struct wan_device *wandev;
363         void __user *data = (void __user *)arg;
364
365         if (!capable(CAP_NET_ADMIN))
366                 return -EPERM;
367
368         if ((cmd >> 8) != ROUTER_IOCTL)
369                 return -EINVAL;
370
371         dent = PDE(inode);
372         if ((dent == NULL) || (dent->data == NULL))
373                 return -EINVAL;
374
375         wandev = dent->data;
376         if (wandev->magic != ROUTER_MAGIC)
377                 return -EINVAL;
378
379         lock_kernel();
380         switch (cmd) {
381         case ROUTER_SETUP:
382                 err = wanrouter_device_setup(wandev, data);
383                 break;
384
385         case ROUTER_DOWN:
386                 err = wanrouter_device_shutdown(wandev);
387                 break;
388
389         case ROUTER_STAT:
390                 err = wanrouter_device_stat(wandev, data);
391                 break;
392
393         case ROUTER_IFNEW:
394                 err = wanrouter_device_new_if(wandev, data);
395                 break;
396
397         case ROUTER_IFDEL:
398                 err = wanrouter_device_del_if(wandev, data);
399                 break;
400
401         case ROUTER_IFSTAT:
402                 break;
403
404         default:
405                 if ((cmd >= ROUTER_USER) &&
406                     (cmd <= ROUTER_USER_MAX) &&
407                     wandev->ioctl)
408                         err = wandev->ioctl(wandev, cmd, arg);
409                 else err = -EINVAL;
410         }
411         unlock_kernel();
412         return err;
413 }
414
415 /*
416  *      WAN Driver IOCTL Handlers
417  */
418
419 /*
420  *      Setup WAN link device.
421  *      o verify user address space
422  *      o allocate kernel memory and copy configuration data to kernel space
423  *      o if configuration data includes extension, copy it to kernel space too
424  *      o call driver's setup() entry point
425  */
426
427 static int wanrouter_device_setup(struct wan_device *wandev,
428                                   wandev_conf_t __user *u_conf)
429 {
430         void *data = NULL;
431         wandev_conf_t *conf;
432         int err = -EINVAL;
433
434         if (wandev->setup == NULL) {    /* Nothing to do ? */
435                 printk(KERN_INFO "%s: ERROR, No setup script: wandev->setup()\n",
436                                 wandev->name);
437                 return 0;
438         }
439
440         conf = kmalloc(sizeof(wandev_conf_t), GFP_KERNEL);
441         if (conf == NULL){
442                 printk(KERN_INFO "%s: ERROR, Failed to allocate kernel memory !\n",
443                                 wandev->name);
444                 return -ENOBUFS;
445         }
446
447         if (copy_from_user(conf, u_conf, sizeof(wandev_conf_t))) {
448                 printk(KERN_INFO "%s: Failed to copy user config data to kernel space!\n",
449                                 wandev->name);
450                 kfree(conf);
451                 return -EFAULT;
452         }
453
454         if (conf->magic != ROUTER_MAGIC) {
455                 kfree(conf);
456                 printk(KERN_INFO "%s: ERROR, Invalid MAGIC Number\n",
457                                 wandev->name);
458                 return -EINVAL;
459         }
460
461         if (conf->data_size && conf->data) {
462                 if (conf->data_size > 128000) {
463                         printk(KERN_INFO
464                             "%s: ERROR, Invalid firmware data size %i !\n",
465                                         wandev->name, conf->data_size);
466                         kfree(conf);
467                         return -EINVAL;
468                 }
469
470                 data = vmalloc(conf->data_size);
471                 if (!data) {
472                         printk(KERN_INFO
473                                 "%s: ERROR, Faild allocate kernel memory !\n",
474                                 wandev->name);
475                         kfree(conf);
476                         return -ENOBUFS;
477                 }
478                 if (!copy_from_user(data, conf->data, conf->data_size)) {
479                         conf->data = data;
480                         err = wandev->setup(wandev, conf);
481                 } else {
482                         printk(KERN_INFO
483                              "%s: ERROR, Faild to copy from user data !\n",
484                                wandev->name);
485                         err = -EFAULT;
486                 }
487                 vfree(data);
488         } else {
489                 printk(KERN_INFO
490                     "%s: ERROR, No firmware found ! Firmware size = %i !\n",
491                                 wandev->name, conf->data_size);
492         }
493
494         kfree(conf);
495         return err;
496 }
497
498 /*
499  *      Shutdown WAN device.
500  *      o delete all not opened logical channels for this device
501  *      o call driver's shutdown() entry point
502  */
503
504 static int wanrouter_device_shutdown(struct wan_device *wandev)
505 {
506         struct net_device *dev;
507         int err=0;
508
509         if (wandev->state == WAN_UNCONFIGURED)
510                 return 0;
511
512         printk(KERN_INFO "\n%s: Shutting Down!\n",wandev->name);
513
514         for (dev = wandev->dev; dev;) {
515                 err = wanrouter_delete_interface(wandev, dev->name);
516                 if (err)
517                         return err;
518                 /* The above function deallocates the current dev
519                  * structure. Therefore, we cannot use netdev_priv(dev)
520                  * as the next element: wandev->dev points to the
521                  * next element */
522                 dev = wandev->dev;
523         }
524
525         if (wandev->ndev)
526                 return -EBUSY;  /* there are opened interfaces  */
527
528         if (wandev->shutdown)
529                 err=wandev->shutdown(wandev);
530
531         return err;
532 }
533
534 /*
535  *      Get WAN device status & statistics.
536  */
537
538 static int wanrouter_device_stat(struct wan_device *wandev,
539                                  wandev_stat_t __user *u_stat)
540 {
541         wandev_stat_t stat;
542
543         memset(&stat, 0, sizeof(stat));
544
545         /* Ask device driver to update device statistics */
546         if ((wandev->state != WAN_UNCONFIGURED) && wandev->update)
547                 wandev->update(wandev);
548
549         /* Fill out structure */
550         stat.ndev  = wandev->ndev;
551         stat.state = wandev->state;
552
553         if (copy_to_user(u_stat, &stat, sizeof(stat)))
554                 return -EFAULT;
555
556         return 0;
557 }
558
559 /*
560  *      Create new WAN interface.
561  *      o verify user address space
562  *      o copy configuration data to kernel address space
563  *      o allocate network interface data space
564  *      o call driver's new_if() entry point
565  *      o make sure there is no interface name conflict
566  *      o register network interface
567  */
568
569 static int wanrouter_device_new_if(struct wan_device *wandev,
570                                    wanif_conf_t __user *u_conf)
571 {
572         wanif_conf_t *cnf;
573         struct net_device *dev = NULL;
574         int err;
575
576         if ((wandev->state == WAN_UNCONFIGURED) || (wandev->new_if == NULL))
577                 return -ENODEV;
578
579         cnf = kmalloc(sizeof(wanif_conf_t), GFP_KERNEL);
580         if (!cnf)
581                 return -ENOBUFS;
582
583         err = -EFAULT;
584         if (copy_from_user(cnf, u_conf, sizeof(wanif_conf_t)))
585                 goto out;
586
587         err = -EINVAL;
588         if (cnf->magic != ROUTER_MAGIC)
589                 goto out;
590
591         if (cnf->config_id == WANCONFIG_MPPP) {
592                 printk(KERN_INFO "%s: Wanpipe Mulit-Port PPP support has not been compiled in!\n",
593                                 wandev->name);
594                 err = -EPROTONOSUPPORT;
595                 goto out;
596         } else {
597                 err = wandev->new_if(wandev, dev, cnf);
598         }
599
600         if (!err) {
601                 /* Register network interface. This will invoke init()
602                  * function supplied by the driver.  If device registered
603                  * successfully, add it to the interface list.
604                  */
605
606                 if (dev->name == NULL) {
607                         err = -EINVAL;
608                 } else {
609
610                         #ifdef WANDEBUG
611                         printk(KERN_INFO "%s: registering interface %s...\n",
612                                 wanrouter_modname, dev->name);
613                         #endif
614
615                         err = register_netdev(dev);
616                         if (!err) {
617                                 struct net_device *slave = NULL;
618                                 unsigned long smp_flags=0;
619
620                                 lock_adapter_irq(&wandev->lock, &smp_flags);
621
622                                 if (wandev->dev == NULL) {
623                                         wandev->dev = dev;
624                                 } else {
625                                         for (slave=wandev->dev;
626                                              DEV_TO_SLAVE(slave);
627                                              slave = DEV_TO_SLAVE(slave))
628                                                 DEV_TO_SLAVE(slave) = dev;
629                                 }
630                                 ++wandev->ndev;
631
632                                 unlock_adapter_irq(&wandev->lock, &smp_flags);
633                                 err = 0;        /* done !!! */
634                                 goto out;
635                         }
636                 }
637                 if (wandev->del_if)
638                         wandev->del_if(wandev, dev);
639                 free_netdev(dev);
640         }
641
642 out:
643         kfree(cnf);
644         return err;
645 }
646
647
648 /*
649  *      Delete WAN logical channel.
650  *       o verify user address space
651  *       o copy configuration data to kernel address space
652  */
653
654 static int wanrouter_device_del_if(struct wan_device *wandev, char __user *u_name)
655 {
656         char name[WAN_IFNAME_SZ + 1];
657         int err = 0;
658
659         if (wandev->state == WAN_UNCONFIGURED)
660                 return -ENODEV;
661
662         memset(name, 0, sizeof(name));
663
664         if (copy_from_user(name, u_name, WAN_IFNAME_SZ))
665                 return -EFAULT;
666
667         err = wanrouter_delete_interface(wandev, name);
668         if (err)
669                 return err;
670
671         /* If last interface being deleted, shutdown card
672          * This helps with administration at leaf nodes
673          * (You can tell if the person at the other end of the phone
674          * has an interface configured) and avoids DoS vulnerabilities
675          * in binary driver files - this fixes a problem with the current
676          * Sangoma driver going into strange states when all the network
677          * interfaces are deleted and the link irrecoverably disconnected.
678          */
679
680         if (!wandev->ndev && wandev->shutdown)
681                 err = wandev->shutdown(wandev);
682
683         return err;
684 }
685
686 /*
687  *      Miscellaneous Functions
688  */
689
690 /*
691  *      Find WAN device by name.
692  *      Return pointer to the WAN device data space or NULL if device not found.
693  */
694
695 static struct wan_device *wanrouter_find_device(char *name)
696 {
697         struct wan_device *wandev;
698
699         for (wandev = wanrouter_router_devlist;
700              wandev && strcmp(wandev->name, name);
701                 wandev = wandev->next);
702         return wandev;
703 }
704
705 /*
706  *      Delete WAN logical channel identified by its name.
707  *      o find logical channel by its name
708  *      o call driver's del_if() entry point
709  *      o unregister network interface
710  *      o unlink channel data space from linked list of channels
711  *      o release channel data space
712  *
713  *      Return: 0               success
714  *              -ENODEV         channel not found.
715  *              -EBUSY          interface is open
716  *
717  *      Note: If (force != 0), then device will be destroyed even if interface
718  *      associated with it is open. It's caller's responsibility to make
719  *      sure that opened interfaces are not removed!
720  */
721
722 static int wanrouter_delete_interface(struct wan_device *wandev, char *name)
723 {
724         struct net_device *dev = NULL, *prev = NULL;
725         unsigned long smp_flags=0;
726
727         lock_adapter_irq(&wandev->lock, &smp_flags);
728         dev = wandev->dev;
729         prev = NULL;
730         while (dev && strcmp(name, dev->name)) {
731                 struct net_device **slave = netdev_priv(dev);
732                 prev = dev;
733                 dev = *slave;
734         }
735         unlock_adapter_irq(&wandev->lock, &smp_flags);
736
737         if (dev == NULL)
738                 return -ENODEV; /* interface not found */
739
740         if (netif_running(dev))
741                 return -EBUSY;  /* interface in use */
742
743         if (wandev->del_if)
744                 wandev->del_if(wandev, dev);
745
746         lock_adapter_irq(&wandev->lock, &smp_flags);
747         if (prev) {
748                 struct net_device **prev_slave = netdev_priv(prev);
749                 struct net_device **slave = netdev_priv(dev);
750
751                 *prev_slave = *slave;
752         } else {
753                 struct net_device **slave = netdev_priv(dev);
754                 wandev->dev = *slave;
755         }
756         --wandev->ndev;
757         unlock_adapter_irq(&wandev->lock, &smp_flags);
758
759         printk(KERN_INFO "%s: unregistering '%s'\n", wandev->name, dev->name);
760
761         unregister_netdev(dev);
762
763         free_netdev(dev);
764
765         return 0;
766 }
767
768 static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
769         __acquires(lock)
770 {
771         spin_lock_irqsave(lock, *smp_flags);
772 }
773
774
775 static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
776         __releases(lock)
777 {
778         spin_unlock_irqrestore(lock, *smp_flags);
779 }
780
781 EXPORT_SYMBOL(register_wan_device);
782 EXPORT_SYMBOL(unregister_wan_device);
783
784 MODULE_LICENSE("GPL");
785
786 /*
787  *      End
788  */