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/mm.h>
  52 #include <linux/string.h>       /* inline mem*, str* functions */
  53
  54 #include <asm/byteorder.h>      /* htons(), etc. */
  55 #include <linux/wanrouter.h>    /* WAN router API definitions */
  56
  57 #include <linux/vmalloc.h>      /* vmalloc, vfree */
  58 #include <asm/uaccess.h>        /* copy_to/from_user */
  59 #include <linux/init.h>         /* __initfunc et al. */
  60
  61 #define KMEM_SAFETYZONE 8
  62
  63 /*
  64  *      Function Prototypes
  65  */
  66
  67 /*
  68  *      WAN device IOCTL handlers
  69  */
  70
  71 static int wanrouter_device_setup(struct wan_device *wandev,
  72                                   wandev_conf_t __user *u_conf);
  73 static int wanrouter_device_stat(struct wan_device *wandev,
  74                                  wandev_stat_t __user *u_stat);
  75 static int wanrouter_device_shutdown(struct wan_device *wandev);
  76 static int wanrouter_device_new_if(struct wan_device *wandev,
  77                                    wanif_conf_t __user *u_conf);
  78 static int wanrouter_device_del_if(struct wan_device *wandev,
  79                                    char __user *u_name);
  80
  81 /*
  82  *      Miscellaneous
  83  */
  84
  85 static struct wan_device *wanrouter_find_device(char *name);
  86 static int wanrouter_delete_interface(struct wan_device *wandev, char *name);
  87 static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags);
  88 static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags);
  89
  90
  91
  92 /*
  93  *      Global Data
  94  */
  95
  96 static char wanrouter_fullname[]  = "Sangoma WANPIPE Router";
  97 static char wanrouter_copyright[] = "(c) 1995-2000 Sangoma Technologies Inc.";
  98 static char wanrouter_modname[] = ROUTER_NAME; /* short module name */
  99 struct wan_device* wanrouter_router_devlist; /* list of registered devices */
 100
 101 /*
 102  *      Organize Unique Identifiers for encapsulation/decapsulation
 103  */
 104
 105 #if 0
 106 static unsigned char wanrouter_oui_ether[] = { 0x00, 0x00, 0x00 };
 107 static unsigned char wanrouter_oui_802_2[] = { 0x00, 0x80, 0xC2 };
 108 #endif
 109
 110 static int __init wanrouter_init(void)
 111 {
 112         int err;
 113
 114         printk(KERN_INFO "%s v%u.%u %s\n",
 115                wanrouter_fullname, ROUTER_VERSION, ROUTER_RELEASE,
 116                wanrouter_copyright);
 117
 118         err = wanrouter_proc_init();
 119         if (err)
 120                 printk(KERN_INFO "%s: can't create entry in proc filesystem!\n",
 121                        wanrouter_modname);
 122
 123         return err;
 124 }
 125
 126 static void __exit wanrouter_cleanup (void)
 127 {
 128         wanrouter_proc_cleanup();
 129 }
 130
 131 /*
 132  * This is just plain dumb.  We should move the bugger to drivers/net/wan,
 133  * slap it first in directory and make it module_init().  The only reason
 134  * for subsys_initcall() here is that net goes after drivers (why, BTW?)
 135  */
 136 subsys_initcall(wanrouter_init);
 137 module_exit(wanrouter_cleanup);
 138
 139 /*
 140  *      Kernel APIs
 141  */
 142
 143 /*
 144  *      Register WAN device.
 145  *      o verify device credentials
 146  *      o create an entry for the device in the /proc/net/router directory
 147  *      o initialize internally maintained fields of the wan_device structure
 148  *      o link device data space to a singly-linked list
 149  *      o if it's the first device, then start kernel 'thread'
 150  *      o increment module use count
 151  *
 152  *      Return:
 153  *      0       Ok
 154  *      < 0     error.
 155  *
 156  *      Context:        process
 157  */
 158
 159
 160 int register_wan_device(struct wan_device *wandev)
 161 {
 162         int err, namelen;
 163
 164         if ((wandev == NULL) || (wandev->magic != ROUTER_MAGIC) ||
 165             (wandev->name == NULL))
 166                 return -EINVAL;
 167
 168         namelen = strlen(wandev->name);
 169         if (!namelen || (namelen > WAN_DRVNAME_SZ))
 170                 return -EINVAL;
 171
 172         if (wanrouter_find_device(wandev->name))
 173                 return -EEXIST;
 174
 175 #ifdef WANDEBUG
 176         printk(KERN_INFO "%s: registering WAN device %s\n",
 177                wanrouter_modname, wandev->name);
 178 #endif
 179
 180         /*
 181          *      Register /proc directory entry
 182          */
 183         err = wanrouter_proc_add(wandev);
 184         if (err) {
 185                 printk(KERN_INFO
 186                         "%s: can't create /proc/net/router/%s entry!\n",
 187                         wanrouter_modname, wandev->name);
 188                 return err;
 189         }
 190
 191         /*
 192          *      Initialize fields of the wan_device structure maintained by the
 193          *      router and update local data.
 194          */
 195
 196         wandev->ndev = 0;
 197         wandev->dev  = NULL;
 198         wandev->next = wanrouter_router_devlist;
 199         wanrouter_router_devlist = wandev;
 200         return 0;
 201 }
 202
 203 /*
 204  *      Unregister WAN device.
 205  *      o shut down device
 206  *      o unlink device data space from the linked list
 207  *      o delete device entry in the /proc/net/router directory
 208  *      o decrement module use count
 209  *
 210  *      Return:         0       Ok
 211  *                      <0      error.
 212  *      Context:        process
 213  */
 214
 215
 216 int unregister_wan_device(char *name)
 217 {
 218         struct wan_device *wandev, *prev;
 219
 220         if (name == NULL)
 221                 return -EINVAL;
 222
 223         for (wandev = wanrouter_router_devlist, prev = NULL;
 224                 wandev && strcmp(wandev->name, name);
 225                 prev = wandev, wandev = wandev->next)
 226                 ;
 227         if (wandev == NULL)
 228                 return -ENODEV;
 229
 230 #ifdef WANDEBUG
 231         printk(KERN_INFO "%s: unregistering WAN device %s\n",
 232                wanrouter_modname, name);
 233 #endif
 234
 235         if (wandev->state != WAN_UNCONFIGURED)
 236                 wanrouter_device_shutdown(wandev);
 237
 238         if (prev)
 239                 prev->next = wandev->next;
 240         else
 241                 wanrouter_router_devlist = wandev->next;
 242
 243         wanrouter_proc_delete(wandev);
 244         return 0;
 245 }
 246
 247 #if 0
 248
 249 /*
 250  *      Encapsulate packet.
 251  *
 252  *      Return: encapsulation header size
 253  *              < 0     - unsupported Ethertype
 254  *
 255  *      Notes:
 256  *      1. This function may be called on interrupt context.
 257  */
 258
 259
 260 int wanrouter_encapsulate(struct sk_buff *skb, struct net_device *dev,
 261                           unsigned short type)
 262 {
 263         int hdr_len = 0;
 264
 265         switch (type) {
 266         case ETH_P_IP:          /* IP datagram encapsulation */
 267                 hdr_len += 1;
 268                 skb_push(skb, 1);
 269                 skb->data[0] = NLPID_IP;
 270                 break;
 271
 272         case ETH_P_IPX:         /* SNAP encapsulation */
 273         case ETH_P_ARP:
 274                 hdr_len += 7;
 275                 skb_push(skb, 7);
 276                 skb->data[0] = 0;
 277                 skb->data[1] = NLPID_SNAP;
 278                 skb_copy_to_linear_data_offset(skb, 2, wanrouter_oui_ether,
 279                                                sizeof(wanrouter_oui_ether));
 280                 *((unsigned short*)&skb->data[5]) = htons(type);
 281                 break;
 282
 283         default:                /* Unknown packet type */
 284                 printk(KERN_INFO
 285                         "%s: unsupported Ethertype 0x%04X on interface %s!\n",
 286                         wanrouter_modname, type, dev->name);
 287                 hdr_len = -EINVAL;
 288         }
 289         return hdr_len;
 290 }
 291
 292
 293 /*
 294  *      Decapsulate packet.
 295  *
 296  *      Return: Ethertype (in network order)
 297  *                      0       unknown encapsulation
 298  *
 299  *      Notes:
 300  *      1. This function may be called on interrupt context.
 301  */
 302
 303
 304 __be16 wanrouter_type_trans(struct sk_buff *skb, struct net_device *dev)
 305 {
 306         int cnt = skb->data[0] ? 0 : 1; /* there may be a pad present */
 307         __be16 ethertype;
 308
 309         switch (skb->data[cnt]) {
 310         case NLPID_IP:          /* IP datagramm */
 311                 ethertype = htons(ETH_P_IP);
 312                 cnt += 1;
 313                 break;
 314
 315         case NLPID_SNAP:        /* SNAP encapsulation */
 316                 if (memcmp(&skb->data[cnt + 1], wanrouter_oui_ether,
 317                            sizeof(wanrouter_oui_ether))){
 318                         printk(KERN_INFO
 319                                 "%s: unsupported SNAP OUI %02X-%02X-%02X "
 320                                 "on interface %s!\n", wanrouter_modname,
 321                                 skb->data[cnt+1], skb->data[cnt+2],
 322                                 skb->data[cnt+3], dev->name);
 323                         return 0;
 324                 }
 325                 ethertype = *((__be16*)&skb->data[cnt+4]);
 326                 cnt += 6;
 327                 break;
 328
 329         /* add other protocols, e.g. CLNP, ESIS, ISIS, if needed */
 330
 331         default:
 332                 printk(KERN_INFO
 333                         "%s: unsupported NLPID 0x%02X on interface %s!\n",
 334                         wanrouter_modname, skb->data[cnt], dev->name);
 335                 return 0;
 336         }
 337         skb->protocol = ethertype;
 338         skb->pkt_type = PACKET_HOST;    /*      Physically point to point */
 339         skb_pull(skb, cnt);
 340         skb_reset_mac_header(skb);
 341         return ethertype;
 342 }
 343
 344 #endif  /*  0  */
 345
 346 /*
 347  *      WAN device IOCTL.
 348  *      o find WAN device associated with this node
 349  *      o execute requested action or pass command to the device driver
 350  */
 351
 352 long wanrouter_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
 353 {
 354         struct inode *inode = file->f_path.dentry->d_inode;
 355         int err = 0;
 356         struct proc_dir_entry *dent;
 357         struct wan_device *wandev;
 358         void __user *data = (void __user *)arg;
 359
 360         if (!capable(CAP_NET_ADMIN))
 361                 return -EPERM;
 362
 363         if ((cmd >> 8) != ROUTER_IOCTL)
 364                 return -EINVAL;
 365
 366         dent = PDE(inode);
 367         if ((dent == NULL) || (dent->data == NULL))
 368                 return -EINVAL;
 369
 370         wandev = dent->data;
 371         if (wandev->magic != ROUTER_MAGIC)
 372                 return -EINVAL;
 373
 374         lock_kernel();
 375         switch (cmd) {
 376         case ROUTER_SETUP:
 377                 err = wanrouter_device_setup(wandev, data);
 378                 break;
 379
 380         case ROUTER_DOWN:
 381                 err = wanrouter_device_shutdown(wandev);
 382                 break;
 383
 384         case ROUTER_STAT:
 385                 err = wanrouter_device_stat(wandev, data);
 386                 break;
 387
 388         case ROUTER_IFNEW:
 389                 err = wanrouter_device_new_if(wandev, data);
 390                 break;
 391
 392         case ROUTER_IFDEL:
 393                 err = wanrouter_device_del_if(wandev, data);
 394                 break;
 395
 396         case ROUTER_IFSTAT:
 397                 break;
 398
 399         default:
 400                 if ((cmd >= ROUTER_USER) &&
 401                     (cmd <= ROUTER_USER_MAX) &&
 402                     wandev->ioctl)
 403                         err = wandev->ioctl(wandev, cmd, arg);
 404                 else err = -EINVAL;
 405         }
 406         unlock_kernel();
 407         return err;
 408 }
 409
 410 /*
 411  *      WAN Driver IOCTL Handlers
 412  */
 413
 414 /*
 415  *      Setup WAN link device.
 416  *      o verify user address space
 417  *      o allocate kernel memory and copy configuration data to kernel space
 418  *      o if configuration data includes extension, copy it to kernel space too
 419  *      o call driver's setup() entry point
 420  */
 421
 422 static int wanrouter_device_setup(struct wan_device *wandev,
 423                                   wandev_conf_t __user *u_conf)
 424 {
 425         void *data = NULL;
 426         wandev_conf_t *conf;
 427         int err = -EINVAL;
 428
 429         if (wandev->setup == NULL) {    /* Nothing to do ? */
 430                 printk(KERN_INFO "%s: ERROR, No setup script: wandev->setup()\n",
 431                                 wandev->name);
 432                 return 0;
 433         }
 434
 435         conf = kmalloc(sizeof(wandev_conf_t), GFP_KERNEL);
 436         if (conf == NULL){
 437                 printk(KERN_INFO "%s: ERROR, Failed to allocate kernel memory !\n",
 438                                 wandev->name);
 439                 return -ENOBUFS;
 440         }
 441
 442         if (copy_from_user(conf, u_conf, sizeof(wandev_conf_t))) {
 443                 printk(KERN_INFO "%s: Failed to copy user config data to kernel space!\n",
 444                                 wandev->name);
 445                 kfree(conf);
 446                 return -EFAULT;
 447         }
 448
 449         if (conf->magic != ROUTER_MAGIC) {
 450                 kfree(conf);
 451                 printk(KERN_INFO "%s: ERROR, Invalid MAGIC Number\n",
 452                                 wandev->name);
 453                 return -EINVAL;
 454         }
 455
 456         if (conf->data_size && conf->data) {
 457                 if (conf->data_size > 128000) {
 458                         printk(KERN_INFO
 459                             "%s: ERROR, Invalid firmware data size %i !\n",
 460                                         wandev->name, conf->data_size);
 461                         kfree(conf);
 462                         return -EINVAL;
 463                 }
 464
 465                 data = vmalloc(conf->data_size);
 466                 if (!data) {
 467                         printk(KERN_INFO
 468                                 "%s: ERROR, Faild allocate kernel memory !\n",
 469                                 wandev->name);
 470                         kfree(conf);
 471                         return -ENOBUFS;
 472                 }
 473                 if (!copy_from_user(data, conf->data, conf->data_size)) {
 474                         conf->data = data;
 475                         err = wandev->setup(wandev, conf);
 476                 } else {
 477                         printk(KERN_INFO
 478                              "%s: ERROR, Faild to copy from user data !\n",
 479                                wandev->name);
 480                         err = -EFAULT;
 481                 }
 482                 vfree(data);
 483         } else {
 484                 printk(KERN_INFO
 485                     "%s: ERROR, No firmware found ! Firmware size = %i !\n",
 486                                 wandev->name, conf->data_size);
 487         }
 488
 489         kfree(conf);
 490         return err;
 491 }
 492
 493 /*
 494  *      Shutdown WAN device.
 495  *      o delete all not opened logical channels for this device
 496  *      o call driver's shutdown() entry point
 497  */
 498
 499 static int wanrouter_device_shutdown(struct wan_device *wandev)
 500 {
 501         struct net_device *dev;
 502         int err=0;
 503
 504         if (wandev->state == WAN_UNCONFIGURED)
 505                 return 0;
 506
 507         printk(KERN_INFO "\n%s: Shutting Down!\n",wandev->name);
 508
 509         for (dev = wandev->dev; dev;) {
 510                 err = wanrouter_delete_interface(wandev, dev->name);
 511                 if (err)
 512                         return err;
 513                 /* The above function deallocates the current dev
 514                  * structure. Therefore, we cannot use dev->priv
 515                  * as the next element: wandev->dev points to the
 516                  * next element */
 517                 dev = wandev->dev;
 518         }
 519
 520         if (wandev->ndev)
 521                 return -EBUSY;  /* there are opened interfaces  */
 522
 523         if (wandev->shutdown)
 524                 err=wandev->shutdown(wandev);
 525
 526         return err;
 527 }
 528
 529 /*
 530  *      Get WAN device status & statistics.
 531  */
 532
 533 static int wanrouter_device_stat(struct wan_device *wandev,
 534                                  wandev_stat_t __user *u_stat)
 535 {
 536         wandev_stat_t stat;
 537
 538         memset(&stat, 0, sizeof(stat));
 539
 540         /* Ask device driver to update device statistics */
 541         if ((wandev->state != WAN_UNCONFIGURED) && wandev->update)
 542                 wandev->update(wandev);
 543
 544         /* Fill out structure */
 545         stat.ndev  = wandev->ndev;
 546         stat.state = wandev->state;
 547
 548         if (copy_to_user(u_stat, &stat, sizeof(stat)))
 549                 return -EFAULT;
 550
 551         return 0;
 552 }
 553
 554 /*
 555  *      Create new WAN interface.
 556  *      o verify user address space
 557  *      o copy configuration data to kernel address space
 558  *      o allocate network interface data space
 559  *      o call driver's new_if() entry point
 560  *      o make sure there is no interface name conflict
 561  *      o register network interface
 562  */
 563
 564 static int wanrouter_device_new_if(struct wan_device *wandev,
 565                                    wanif_conf_t __user *u_conf)
 566 {
 567         wanif_conf_t *cnf;
 568         struct net_device *dev = NULL;
 569         int err;
 570
 571         if ((wandev->state == WAN_UNCONFIGURED) || (wandev->new_if == NULL))
 572                 return -ENODEV;
 573
 574         cnf = kmalloc(sizeof(wanif_conf_t), GFP_KERNEL);
 575         if (!cnf)
 576                 return -ENOBUFS;
 577
 578         err = -EFAULT;
 579         if (copy_from_user(cnf, u_conf, sizeof(wanif_conf_t)))
 580                 goto out;
 581
 582         err = -EINVAL;
 583         if (cnf->magic != ROUTER_MAGIC)
 584                 goto out;
 585
 586         if (cnf->config_id == WANCONFIG_MPPP) {
 587                 printk(KERN_INFO "%s: Wanpipe Mulit-Port PPP support has not been compiled in!\n",
 588                                 wandev->name);
 589                 err = -EPROTONOSUPPORT;
 590                 goto out;
 591         } else {
 592                 dev = kzalloc(sizeof(struct net_device), GFP_KERNEL);
 593                 err = -ENOBUFS;
 594                 if (dev == NULL)
 595                         goto out;
 596                 err = wandev->new_if(wandev, dev, cnf);
 597         }
 598
 599         if (!err) {
 600                 /* Register network interface. This will invoke init()
 601                  * function supplied by the driver.  If device registered
 602                  * successfully, add it to the interface list.
 603                  */
 604
 605                 if (dev->name == NULL) {
 606                         err = -EINVAL;
 607                 } else {
 608
 609                         #ifdef WANDEBUG
 610                         printk(KERN_INFO "%s: registering interface %s...\n",
 611                                 wanrouter_modname, dev->name);
 612                         #endif
 613
 614                         err = register_netdev(dev);
 615                         if (!err) {
 616                                 struct net_device *slave = NULL;
 617                                 unsigned long smp_flags=0;
 618
 619                                 lock_adapter_irq(&wandev->lock, &smp_flags);
 620
 621                                 if (wandev->dev == NULL) {
 622                                         wandev->dev = dev;
 623                                 } else {
 624                                         for (slave=wandev->dev;
 625                                          *((struct net_device **)slave->priv);
 626                                  slave = *((struct net_device **)slave->priv));
 627
 628                                      *((struct net_device **)slave->priv) = 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         }
 640
 641         /* This code has moved from del_if() function */
 642         kfree(dev->priv);
 643         dev->priv = NULL;
 644
 645         /* Sync PPP is disabled */
 646         if (cnf->config_id != WANCONFIG_MPPP)
 647                 kfree(dev);
 648 out:
 649         kfree(cnf);
 650         return err;
 651 }
 652
 653
 654 /*
 655  *      Delete WAN logical channel.
 656  *       o verify user address space
 657  *       o copy configuration data to kernel address space
 658  */
 659
 660 static int wanrouter_device_del_if(struct wan_device *wandev, char __user *u_name)
 661 {
 662         char name[WAN_IFNAME_SZ + 1];
 663         int err = 0;
 664
 665         if (wandev->state == WAN_UNCONFIGURED)
 666                 return -ENODEV;
 667
 668         memset(name, 0, sizeof(name));
 669
 670         if (copy_from_user(name, u_name, WAN_IFNAME_SZ))
 671                 return -EFAULT;
 672
 673         err = wanrouter_delete_interface(wandev, name);
 674         if (err)
 675                 return err;
 676
 677         /* If last interface being deleted, shutdown card
 678          * This helps with administration at leaf nodes
 679          * (You can tell if the person at the other end of the phone
 680          * has an interface configured) and avoids DoS vulnerabilities
 681          * in binary driver files - this fixes a problem with the current
 682          * Sangoma driver going into strange states when all the network
 683          * interfaces are deleted and the link irrecoverably disconnected.
 684          */
 685
 686         if (!wandev->ndev && wandev->shutdown)
 687                 err = wandev->shutdown(wandev);
 688
 689         return err;
 690 }
 691
 692 /*
 693  *      Miscellaneous Functions
 694  */
 695
 696 /*
 697  *      Find WAN device by name.
 698  *      Return pointer to the WAN device data space or NULL if device not found.
 699  */
 700
 701 static struct wan_device *wanrouter_find_device(char *name)
 702 {
 703         struct wan_device *wandev;
 704
 705         for (wandev = wanrouter_router_devlist;
 706              wandev && strcmp(wandev->name, name);
 707                 wandev = wandev->next);
 708         return wandev;
 709 }
 710
 711 /*
 712  *      Delete WAN logical channel identified by its name.
 713  *      o find logical channel by its name
 714  *      o call driver's del_if() entry point
 715  *      o unregister network interface
 716  *      o unlink channel data space from linked list of channels
 717  *      o release channel data space
 718  *
 719  *      Return: 0               success
 720  *              -ENODEV         channel not found.
 721  *              -EBUSY          interface is open
 722  *
 723  *      Note: If (force != 0), then device will be destroyed even if interface
 724  *      associated with it is open. It's caller's responsibility to make
 725  *      sure that opened interfaces are not removed!
 726  */
 727
 728 static int wanrouter_delete_interface(struct wan_device *wandev, char *name)
 729 {
 730         struct net_device *dev = NULL, *prev = NULL;
 731         unsigned long smp_flags=0;
 732
 733         lock_adapter_irq(&wandev->lock, &smp_flags);
 734         dev = wandev->dev;
 735         prev = NULL;
 736         while (dev && strcmp(name, dev->name)) {
 737                 struct net_device **slave = dev->priv;
 738                 prev = dev;
 739                 dev = *slave;
 740         }
 741         unlock_adapter_irq(&wandev->lock, &smp_flags);
 742
 743         if (dev == NULL)
 744                 return -ENODEV; /* interface not found */
 745
 746         if (netif_running(dev))
 747                 return -EBUSY;  /* interface in use */
 748
 749         if (wandev->del_if)
 750                 wandev->del_if(wandev, dev);
 751
 752         lock_adapter_irq(&wandev->lock, &smp_flags);
 753         if (prev) {
 754                 struct net_device **prev_slave = prev->priv;
 755                 struct net_device **slave = dev->priv;
 756
 757                 *prev_slave = *slave;
 758         } else {
 759                 struct net_device **slave = dev->priv;
 760                 wandev->dev = *slave;
 761         }
 762         --wandev->ndev;
 763         unlock_adapter_irq(&wandev->lock, &smp_flags);
 764
 765         printk(KERN_INFO "%s: unregistering '%s'\n", wandev->name, dev->name);
 766
 767         /* Due to new interface linking method using dev->priv,
 768          * this code has moved from del_if() function.*/
 769         kfree(dev->priv);
 770         dev->priv=NULL;
 771
 772         unregister_netdev(dev);
 773
 774         free_netdev(dev);
 775
 776         return 0;
 777 }
 778
 779 static void lock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
 780 {
 781         spin_lock_irqsave(lock, *smp_flags);
 782 }
 783
 784
 785 static void unlock_adapter_irq(spinlock_t *lock, unsigned long *smp_flags)
 786 {
 787         spin_unlock_irqrestore(lock, *smp_flags);
 788 }
 789
 790 EXPORT_SYMBOL(register_wan_device);
 791 EXPORT_SYMBOL(unregister_wan_device);
 792
 793 MODULE_LICENSE("GPL");
 794
 795 /*
 796  *      End
 797  */