The Tcpdump Group git mirrors - libpcap/blob - inet.c

   1 /* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
   2 /*
   3  * Copyright (c) 1994, 1995, 1996, 1997, 1998
   4  *      The Regents of the University of California.  All rights reserved.
   5  *
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions
   8  * are met:
   9  * 1. Redistributions of source code must retain the above copyright
  10  *    notice, this list of conditions and the following disclaimer.
  11  * 2. Redistributions in binary form must reproduce the above copyright
  12  *    notice, this list of conditions and the following disclaimer in the
  13  *    documentation and/or other materials provided with the distribution.
  14  * 3. All advertising materials mentioning features or use of this software
  15  *    must display the following acknowledgement:
  16  *      This product includes software developed by the Computer Systems
  17  *      Engineering Group at Lawrence Berkeley Laboratory.
  18  * 4. Neither the name of the University nor of the Laboratory may be used
  19  *    to endorse or promote products derived from this software without
  20  *    specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #ifndef lint
  36 static const char rcsid[] _U_ =
  37     "@(#) $Header: /tcpdump/master/libpcap/inet.c,v 1.61 2004-12-16 22:07:28 guy Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #ifdef WIN32
  45 #include <pcap-stdinc.h>
  46 #else /* WIN32 */
  47
  48 #include <sys/param.h>
  49 #include <sys/file.h>
  50 #include <sys/ioctl.h>
  51 #include <sys/socket.h>
  52 #ifdef HAVE_SYS_SOCKIO_H
  53 #include <sys/sockio.h>
  54 #endif
  55 #include <sys/time.h>                           /* concession to AIX */
  56
  57 struct mbuf;            /* Squelch compiler warnings on some platforms for */
  58 struct rtentry;         /* declarations in <net/if.h> */
  59 #include <net/if.h>
  60 #include <netinet/in.h>
  61 #endif /* WIN32 */
  62
  63 #include <ctype.h>
  64 #include <errno.h>
  65 #include <memory.h>
  66 #include <stdio.h>
  67 #include <stdlib.h>
  68 #include <string.h>
  69 #ifndef WIN32
  70 #include <unistd.h>
  71 #endif /* WIN32 */
  72 #ifdef HAVE_LIMITS_H
  73 #include <limits.h>
  74 #else
  75 #define INT_MAX         2147483647
  76 #endif
  77
  78 #include "pcap-int.h"
  79
  80 #ifdef HAVE_OS_PROTO_H
  81 #include "os-proto.h"
  82 #endif
  83
  84 /* Not all systems have IFF_LOOPBACK */
  85 #ifdef IFF_LOOPBACK
  86 #define ISLOOPBACK(name, flags) ((flags) & IFF_LOOPBACK)
  87 #else
  88 #define ISLOOPBACK(name, flags) ((name)[0] == 'l' && (name)[1] == 'o' && \
  89     (isdigit((unsigned char)((name)[2])) || (name)[2] == '\0'))
  90 #endif
  91
  92 struct sockaddr *
  93 dup_sockaddr(struct sockaddr *sa, size_t sa_length)
  94 {
  95         struct sockaddr *newsa;
  96
  97         if ((newsa = malloc(sa_length)) == NULL)
  98                 return (NULL);
  99         return (memcpy(newsa, sa, sa_length));
 100 }
 101
 102 static int
 103 get_instance(const char *name)
 104 {
 105         const char *cp, *endcp;
 106         int n;
 107
 108         if (strcmp(name, "any") == 0) {
 109                 /*
 110                  * Give the "any" device an artificially high instance
 111                  * number, so it shows up after all other non-loopback
 112                  * interfaces.
 113                  */
 114                 return INT_MAX;
 115         }
 116
 117         endcp = name + strlen(name);
 118         for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp)
 119                 continue;
 120
 121         if (isdigit((unsigned char)*cp))
 122                 n = atoi(cp);
 123         else
 124                 n = 0;
 125         return (n);
 126 }
 127
 128 int
 129 add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name,
 130     u_int flags, const char *description, char *errbuf)
 131 {
 132         pcap_if_t *curdev, *prevdev, *nextdev;
 133         int this_instance;
 134
 135         /*
 136          * Is there already an entry in the list for this interface?
 137          */
 138         for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) {
 139                 if (strcmp(name, curdev->name) == 0)
 140                         break;  /* yes, we found it */
 141         }
 142         if (curdev == NULL) {
 143                 /*
 144                  * No, we didn't find it.
 145                  * Allocate a new entry.
 146                  */
 147                 curdev = malloc(sizeof(pcap_if_t));
 148                 if (curdev == NULL) {
 149                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 150                             "malloc: %s", pcap_strerror(errno));
 151                         return (-1);
 152                 }
 153
 154                 /*
 155                  * Fill in the entry.
 156                  */
 157                 curdev->next = NULL;
 158                 curdev->name = malloc(strlen(name) + 1);
 159                 strcpy(curdev->name, name);
 160                 if (description != NULL) {
 161                         /*
 162                          * We have a description for this interface.
 163                          */
 164                         curdev->description = malloc(strlen(description) + 1);
 165                         strcpy(curdev->description, description);
 166                 } else {
 167                         /*
 168                          * We don't.
 169                          */
 170                         curdev->description = NULL;
 171                 }
 172                 curdev->addresses = NULL;       /* list starts out as empty */
 173                 curdev->flags = 0;
 174                 if (ISLOOPBACK(name, flags))
 175                         curdev->flags |= PCAP_IF_LOOPBACK;
 176
 177                 /*
 178                  * Add it to the list, in the appropriate location.
 179                  * First, get the instance number of this interface.
 180                  */
 181                 this_instance = get_instance(name);
 182
 183                 /*
 184                  * Now look for the last interface with an instance number
 185                  * less than or equal to the new interface's instance
 186                  * number - except that non-loopback interfaces are
 187                  * arbitrarily treated as having interface numbers less
 188                  * than those of loopback interfaces, so the loopback
 189                  * interfaces are put at the end of the list.
 190                  *
 191                  * We start with "prevdev" being NULL, meaning we're before
 192                  * the first element in the list.
 193                  */
 194                 prevdev = NULL;
 195                 for (;;) {
 196                         /*
 197                          * Get the interface after this one.
 198                          */
 199                         if (prevdev == NULL) {
 200                                 /*
 201                                  * The next element is the first element.
 202                                  */
 203                                 nextdev = *alldevs;
 204                         } else
 205                                 nextdev = prevdev->next;
 206
 207                         /*
 208                          * Are we at the end of the list?
 209                          */
 210                         if (nextdev == NULL) {
 211                                 /*
 212                                  * Yes - we have to put the new entry
 213                                  * after "prevdev".
 214                                  */
 215                                 break;
 216                         }
 217
 218                         /*
 219                          * Is the new interface a non-loopback interface
 220                          * and the next interface a loopback interface?
 221                          */
 222                         if (!(curdev->flags & PCAP_IF_LOOPBACK) &&
 223                             (nextdev->flags & PCAP_IF_LOOPBACK)) {
 224                                 /*
 225                                  * Yes, we should put the new entry
 226                                  * before "nextdev", i.e. after "prevdev".
 227                                  */
 228                                 break;
 229                         }
 230
 231                         /*
 232                          * Is the new interface's instance number less
 233                          * than the next interface's instance number,
 234                          * and is it the case that the new interface is a
 235                          * non-loopback interface or the next interface is
 236                          * a loopback interface?
 237                          *
 238                          * (The goal of both loopback tests is to make
 239                          * sure that we never put a loopback interface
 240                          * before any non-loopback interface and that we
 241                          * always put a non-loopback interface before all
 242                          * loopback interfaces.)
 243                          */
 244                         if (this_instance < get_instance(nextdev->name) &&
 245                             (!(curdev->flags & PCAP_IF_LOOPBACK) ||
 246                                (nextdev->flags & PCAP_IF_LOOPBACK))) {
 247                                 /*
 248                                  * Yes - we should put the new entry
 249                                  * before "nextdev", i.e. after "prevdev".
 250                                  */
 251                                 break;
 252                         }
 253
 254                         prevdev = nextdev;
 255                 }
 256
 257                 /*
 258                  * Insert before "nextdev".
 259                  */
 260                 curdev->next = nextdev;
 261
 262                 /*
 263                  * Insert after "prevdev" - unless "prevdev" is null,
 264                  * in which case this is the first interface.
 265                  */
 266                 if (prevdev == NULL) {
 267                         /*
 268                          * This is the first interface.  Pass back a
 269                          * pointer to it, and put "curdev" before
 270                          * "nextdev".
 271                          */
 272                         *alldevs = curdev;
 273                 } else
 274                         prevdev->next = curdev;
 275         }
 276
 277         *curdev_ret = curdev;
 278         return (0);
 279 }
 280
 281 int
 282 add_addr_to_iflist(pcap_if_t **alldevs, char *name, u_int flags,
 283     struct sockaddr *addr, size_t addr_size,
 284     struct sockaddr *netmask, size_t netmask_size,
 285     struct sockaddr *broadaddr, size_t broadaddr_size,
 286     struct sockaddr *dstaddr, size_t dstaddr_size,
 287     char *errbuf)
 288 {
 289         pcap_if_t *curdev;
 290         pcap_addr_t *curaddr, *prevaddr, *nextaddr;
 291
 292         if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) {
 293                 /*
 294                  * Error - give up.
 295                  */
 296                 return (-1);
 297         }
 298         if (curdev == NULL) {
 299                 /*
 300                  * Device wasn't added because it can't be opened.
 301                  * Not a fatal error.
 302                  */
 303                 return (0);
 304         }
 305
 306         /*
 307          * "curdev" is an entry for this interface; add an entry for this
 308          * address to its list of addresses.
 309          *
 310          * Allocate the new entry and fill it in.
 311          */
 312         curaddr = malloc(sizeof(pcap_addr_t));
 313         if (curaddr == NULL) {
 314                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 315                     "malloc: %s", pcap_strerror(errno));
 316                 return (-1);
 317         }
 318
 319         curaddr->next = NULL;
 320         if (addr != NULL) {
 321                 curaddr->addr = dup_sockaddr(addr, addr_size);
 322                 if (curaddr->addr == NULL) {
 323                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 324                             "malloc: %s", pcap_strerror(errno));
 325                         free(curaddr);
 326                         return (-1);
 327                 }
 328         } else
 329                 curaddr->addr = NULL;
 330
 331         if (netmask != NULL) {
 332                 curaddr->netmask = dup_sockaddr(netmask, netmask_size);
 333                 if (curaddr->netmask == NULL) {
 334                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 335                             "malloc: %s", pcap_strerror(errno));
 336                         free(curaddr);
 337                         return (-1);
 338                 }
 339         } else
 340                 curaddr->netmask = NULL;
 341
 342         if (broadaddr != NULL) {
 343                 curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size);
 344                 if (curaddr->broadaddr == NULL) {
 345                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 346                             "malloc: %s", pcap_strerror(errno));
 347                         free(curaddr);
 348                         return (-1);
 349                 }
 350         } else
 351                 curaddr->broadaddr = NULL;
 352
 353         if (dstaddr != NULL) {
 354                 curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size);
 355                 if (curaddr->dstaddr == NULL) {
 356                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 357                             "malloc: %s", pcap_strerror(errno));
 358                         free(curaddr);
 359                         return (-1);
 360                 }
 361         } else
 362                 curaddr->dstaddr = NULL;
 363
 364         /*
 365          * Find the end of the list of addresses.
 366          */
 367         for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) {
 368                 nextaddr = prevaddr->next;
 369                 if (nextaddr == NULL) {
 370                         /*
 371                          * This is the end of the list.
 372                          */
 373                         break;
 374                 }
 375         }
 376
 377         if (prevaddr == NULL) {
 378                 /*
 379                  * The list was empty; this is the first member.
 380                  */
 381                 curdev->addresses = curaddr;
 382         } else {
 383                 /*
 384                  * "prevaddr" is the last member of the list; append
 385                  * this member to it.
 386                  */
 387                 prevaddr->next = curaddr;
 388         }
 389
 390         return (0);
 391 }
 392
 393 int
 394 pcap_add_if(pcap_if_t **devlist, char *name, u_int flags,
 395     const char *description, char *errbuf)
 396 {
 397         pcap_if_t *curdev;
 398
 399         return (add_or_find_if(&curdev, devlist, name, flags, description,
 400             errbuf));
 401 }
 402
 403
 404 /*
 405  * Free a list of interfaces.
 406  */
 407 void
 408 pcap_freealldevs(pcap_if_t *alldevs)
 409 {
 410         pcap_if_t *curdev, *nextdev;
 411         pcap_addr_t *curaddr, *nextaddr;
 412
 413         for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
 414                 nextdev = curdev->next;
 415
 416                 /*
 417                  * Free all addresses.
 418                  */
 419                 for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) {
 420                         nextaddr = curaddr->next;
 421                         if (curaddr->addr)
 422                                 free(curaddr->addr);
 423                         if (curaddr->netmask)
 424                                 free(curaddr->netmask);
 425                         if (curaddr->broadaddr)
 426                                 free(curaddr->broadaddr);
 427                         if (curaddr->dstaddr)
 428                                 free(curaddr->dstaddr);
 429                         free(curaddr);
 430                 }
 431
 432                 /*
 433                  * Free the name string.
 434                  */
 435                 free(curdev->name);
 436
 437                 /*
 438                  * Free the description string, if any.
 439                  */
 440                 if (curdev->description != NULL)
 441                         free(curdev->description);
 442
 443                 /*
 444                  * Free the interface.
 445                  */
 446                 free(curdev);
 447         }
 448 }
 449
 450 #ifndef WIN32
 451
 452 /*
 453  * Return the name of a network interface attached to the system, or NULL
 454  * if none can be found.  The interface must be configured up; the
 455  * lowest unit number is preferred; loopback is ignored.
 456  */
 457 char *
 458 pcap_lookupdev(errbuf)
 459         register char *errbuf;
 460 {
 461         pcap_if_t *alldevs;
 462 /* for old BSD systems, including bsdi3 */
 463 #ifndef IF_NAMESIZE
 464 #define IF_NAMESIZE IFNAMSIZ
 465 #endif
 466         static char device[IF_NAMESIZE + 1];
 467         char *ret;
 468
 469         if (pcap_findalldevs(&alldevs, errbuf) == -1)
 470                 return (NULL);
 471
 472         if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) {
 473                 /*
 474                  * There are no devices on the list, or the first device
 475                  * on the list is a loopback device, which means there
 476                  * are no non-loopback devices on the list.  This means
 477                  * we can't return any device.
 478                  *
 479                  * XXX - why not return a loopback device?  If we can't
 480                  * capture on it, it won't be on the list, and if it's
 481                  * on the list, there aren't any non-loopback devices,
 482                  * so why not just supply it as the default device?
 483                  */
 484                 (void)strlcpy(errbuf, "no suitable device found",
 485                     PCAP_ERRBUF_SIZE);
 486                 ret = NULL;
 487         } else {
 488                 /*
 489                  * Return the name of the first device on the list.
 490                  */
 491                 (void)strlcpy(device, alldevs->name, sizeof(device));
 492                 ret = device;
 493         }
 494
 495         pcap_freealldevs(alldevs);
 496         return (ret);
 497 }
 498
 499 int
 500 pcap_lookupnet(device, netp, maskp, errbuf)
 501         register const char *device;
 502         register bpf_u_int32 *netp, *maskp;
 503         register char *errbuf;
 504 {
 505         register int fd;
 506         register struct sockaddr_in *sin;
 507         struct ifreq ifr;
 508
 509         /*
 510          * The pseudo-device "any" listens on all interfaces and therefore
 511          * has the network address and -mask "0.0.0.0" therefore catching
 512          * all traffic. Using NULL for the interface is the same as "any".
 513          */
 514         if (!device || strcmp(device, "any") == 0
 515 #ifdef HAVE_DAG_API
 516             || strstr(device, "dag") != NULL
 517 #endif
 518             ) {
 519                 *netp = *maskp = 0;
 520                 return 0;
 521         }
 522
 523         fd = socket(AF_INET, SOCK_DGRAM, 0);
 524         if (fd < 0) {
 525                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
 526                     pcap_strerror(errno));
 527                 return (-1);
 528         }
 529         memset(&ifr, 0, sizeof(ifr));
 530 #ifdef linux
 531         /* XXX Work around Linux kernel bug */
 532         ifr.ifr_addr.sa_family = AF_INET;
 533 #endif
 534         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 535         if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
 536                 if (errno == EADDRNOTAVAIL) {
 537                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 538                             "%s: no IPv4 address assigned", device);
 539                 } else {
 540                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 541                             "SIOCGIFADDR: %s: %s",
 542                             device, pcap_strerror(errno));
 543                 }
 544                 (void)close(fd);
 545                 return (-1);
 546         }
 547         sin = (struct sockaddr_in *)&ifr.ifr_addr;
 548         *netp = sin->sin_addr.s_addr;
 549         if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
 550                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 551                     "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
 552                 (void)close(fd);
 553                 return (-1);
 554         }
 555         (void)close(fd);
 556         *maskp = sin->sin_addr.s_addr;
 557         if (*maskp == 0) {
 558                 if (IN_CLASSA(*netp))
 559                         *maskp = IN_CLASSA_NET;
 560                 else if (IN_CLASSB(*netp))
 561                         *maskp = IN_CLASSB_NET;
 562                 else if (IN_CLASSC(*netp))
 563                         *maskp = IN_CLASSC_NET;
 564                 else {
 565                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 566                             "inet class for 0x%x unknown", *netp);
 567                         return (-1);
 568                 }
 569         }
 570         *netp &= *maskp;
 571         return (0);
 572 }
 573
 574 #else /* WIN32 */
 575
 576 /*
 577  * Return the name of a network interface attached to the system, or NULL
 578  * if none can be found.  The interface must be configured up; the
 579  * lowest unit number is preferred; loopback is ignored.
 580  */
 581 char *
 582 pcap_lookupdev(errbuf)
 583         register char *errbuf;
 584 {
 585         DWORD dwVersion;
 586         DWORD dwWindowsMajorVersion;
 587         dwVersion = GetVersion();       /* get the OS version */
 588         dwWindowsMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
 589
 590         if (dwVersion >= 0x80000000 && dwWindowsMajorVersion >= 4) {
 591                 /*
 592                  * Windows 95, 98, ME.
 593                  */
 594                 ULONG NameLength = 8192;
 595                 static char AdaptersName[8192];
 596
 597                 if (PacketGetAdapterNames(AdaptersName,&NameLength) )
 598                         return (AdaptersName);
 599                 else
 600                         return NULL;
 601         } else {
 602                 /*
 603                  * Windows NT (NT 4.0, W2K, WXP). Convert the names to UNICODE for backward compatibility
 604                  */
 605                 ULONG NameLength = 8192;
 606                 static WCHAR AdaptersName[8192];
 607                 char *tAstr;
 608                 WCHAR *tUstr;
 609                 WCHAR *TAdaptersName = (WCHAR*)malloc(8192 * sizeof(WCHAR));
 610                 int NAdapts = 0;
 611
 612                 if(TAdaptersName == NULL)
 613                 {
 614                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "memory allocation failure");
 615                         return NULL;
 616                 }
 617
 618                 if ( !PacketGetAdapterNames((PTSTR)TAdaptersName,&NameLength) )
 619                 {
 620                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 621                                 "PacketGetAdapterNames: %s",
 622                                 pcap_win32strerror());
 623                         free(TAdaptersName);
 624                         return NULL;
 625                 }
 626
 627
 628                 tAstr = (char*)TAdaptersName;
 629                 tUstr = (WCHAR*)AdaptersName;
 630
 631                 /*
 632                  * Convert and copy the device names
 633                  */
 634                 while(sscanf(tAstr, "%S", tUstr) > 0)
 635                 {
 636                         tAstr += strlen(tAstr) + 1;
 637                         tUstr += wcslen(tUstr) + 1;
 638                         NAdapts ++;
 639                 }
 640
 641                 tAstr++;
 642                 *tUstr = 0;
 643                 tUstr++;
 644
 645                 /*
 646                  * Copy the descriptions
 647                  */
 648                 while(NAdapts--)
 649                 {
 650                         strcpy((char*)tUstr, tAstr);
 651                         (char*)tUstr += strlen(tAstr) + 1;;
 652                         tAstr += strlen(tAstr) + 1;
 653                 }
 654
 655                 free(TAdaptersName);
 656                 return (char *)(AdaptersName);
 657         }
 658 }
 659
 660
 661 int
 662 pcap_lookupnet(device, netp, maskp, errbuf)
 663         const register char *device;
 664         register bpf_u_int32 *netp, *maskp;
 665         register char *errbuf;
 666 {
 667         /*
 668          * We need only the first IPv4 address, so we must scan the array returned by PacketGetNetInfo()
 669          * in order to skip non IPv4 (i.e. IPv6 addresses)
 670          */
 671         npf_if_addr if_addrs[MAX_NETWORK_ADDRESSES];
 672         LONG if_addr_size = 1;
 673         struct sockaddr_in *t_addr;
 674         unsigned int i;
 675
 676         if (!PacketGetNetInfoEx((void *)device, if_addrs, &if_addr_size)) {
 677                 *netp = *maskp = 0;
 678                 return (0);
 679         }
 680
 681         for(i=0; i<MAX_NETWORK_ADDRESSES; i++)
 682         {
 683                 if(if_addrs[i].IPAddress.ss_family == AF_INET)
 684                 {
 685                         t_addr = (struct sockaddr_in *) &(if_addrs[i].IPAddress);
 686                         *netp = t_addr->sin_addr.S_un.S_addr;
 687                         t_addr = (struct sockaddr_in *) &(if_addrs[i].SubnetMask);
 688                         *maskp = t_addr->sin_addr.S_un.S_addr;
 689
 690                         *netp &= *maskp;
 691                         return (0);
 692                 }
 693
 694         }
 695
 696         *netp = *maskp = 0;
 697         return (0);
 698 }
 699
 700 #endif /* WIN32 */