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[] =
  37     "@(#) $Header: /tcpdump/master/libpcap/inet.c,v 1.51 2002-08-01 08:33:02 risso Exp $ (LBL)";
  38 #endif
  39
  40 #ifdef HAVE_CONFIG_H
  41 #include "config.h"
  42 #endif
  43
  44 #include <pcap-stdinc.h>
  45 #ifdef HAVE_SYS_SOCKIO_H
  46 #include <sys/sockio.h>
  47 #endif
  48
  49 struct mbuf;            /* Squelch compiler warnings on some platforms for */
  50 struct rtentry;         /* declarations in <net/if.h> */
  51 #include <net/if.h>
  52
  53 #include <ctype.h>
  54 #include <errno.h>
  55 #include <memory.h>
  56 #include <stdio.h>
  57 #include <stdlib.h>
  58 #include <string.h>
  59 #ifdef HAVE_LIMITS_H
  60 #include <limits.h>
  61 #else
  62 #define INT_MAX         2147483647
  63 #endif
  64 #ifdef HAVE_IFADDRS_H
  65 #include <ifaddrs.h>
  66 #endif
  67
  68 #include "pcap-int.h"
  69
  70 #ifdef HAVE_OS_PROTO_H
  71 #include "os-proto.h"
  72 #endif
  73
  74 /* Not all systems have IFF_LOOPBACK */
  75 #ifdef IFF_LOOPBACK
  76 #define ISLOOPBACK(name, flags) ((flags) & IFF_LOOPBACK)
  77 #else
  78 #define ISLOOPBACK(name, flags) ((name)[0] == 'l' && (name)[1] == 'o' && \
  79     (isdigit((unsigned char)((name)[2])) || (name)[2] == '\0'))
  80 #endif
  81
  82 struct sockaddr *
  83 dup_sockaddr(struct sockaddr *sa, size_t sa_len)
  84 {
  85         struct sockaddr *newsa;
  86
  87         if ((newsa = malloc(sa_len)) == NULL)
  88                 return (NULL);
  89         return (memcpy(newsa, sa, sa_len));
  90 }
  91
  92 static int
  93 get_instance(char *name)
  94 {
  95         char *cp, *endcp;
  96         int n;
  97
  98         if (strcmp(name, "any") == 0) {
  99                 /*
 100                  * Give the "any" device an artificially high instance
 101                  * number, so it shows up after all other non-loopback
 102                  * interfaces.
 103                  */
 104                 return INT_MAX;
 105         }
 106
 107         endcp = name + strlen(name);
 108         for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp)
 109                 continue;
 110
 111         if (isdigit((unsigned char)*cp))
 112                 n = atoi(cp);
 113         else
 114                 n = 0;
 115         return (n);
 116 }
 117
 118 int
 119 add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, char *name,
 120     u_int flags, const char *description, char *errbuf)
 121 {
 122         pcap_t *p;
 123         pcap_if_t *curdev, *prevdev, *nextdev;
 124         int this_instance;
 125
 126         /*
 127          * Can we open this interface for live capture?
 128          */
 129         p = pcap_open_live(name, 68, 0, 0, errbuf);
 130         if (p == NULL) {
 131                 /*
 132                  * No.  Don't bother including it.
 133                  * Don't treat this as an error, though.
 134                  */
 135                 *curdev_ret = NULL;
 136                 return (0);
 137         }
 138         pcap_close(p);
 139
 140         /*
 141          * Is there already an entry in the list for this interface?
 142          */
 143         for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) {
 144                 if (strcmp(name, curdev->name) == 0)
 145                         break;  /* yes, we found it */
 146         }
 147         if (curdev == NULL) {
 148                 /*
 149                  * No, we didn't find it.
 150                  * Allocate a new entry.
 151                  */
 152                 curdev = malloc(sizeof(pcap_if_t));
 153                 if (curdev == NULL) {
 154                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 155                             "malloc: %s", pcap_strerror(errno));
 156                         return (-1);
 157                 }
 158
 159                 /*
 160                  * Fill in the entry.
 161                  */
 162                 curdev->next = NULL;
 163                 curdev->name = malloc(strlen(name) + 1);
 164                 strcpy(curdev->name, name);
 165                 if (description != NULL) {
 166                         /*
 167                          * We have a description for this interface.
 168                          */
 169                         curdev->description = malloc(strlen(description) + 1);
 170                         strcpy(curdev->description, description);
 171                 } else {
 172                         /*
 173                          * We don't.
 174                          */
 175                         curdev->description = NULL;
 176                 }
 177                 curdev->addresses = NULL;       /* list starts out as empty */
 178                 curdev->flags = 0;
 179                 if (ISLOOPBACK(name, flags))
 180                         curdev->flags |= PCAP_IF_LOOPBACK;
 181
 182                 /*
 183                  * Add it to the list, in the appropriate location.
 184                  * First, get the instance number of this interface.
 185                  */
 186                 this_instance = get_instance(name);
 187
 188                 /*
 189                  * Now look for the last interface with an instance number
 190                  * less than or equal to the new interface's instance
 191                  * number - except that non-loopback interfaces are
 192                  * arbitrarily treated as having interface numbers less
 193                  * than those of loopback interfaces, so the loopback
 194                  * interfaces are put at the end of the list.
 195                  *
 196                  * We start with "prevdev" being NULL, meaning we're before
 197                  * the first element in the list.
 198                  */
 199                 prevdev = NULL;
 200                 for (;;) {
 201                         /*
 202                          * Get the interface after this one.
 203                          */
 204                         if (prevdev == NULL) {
 205                                 /*
 206                                  * The next element is the first element.
 207                                  */
 208                                 nextdev = *alldevs;
 209                         } else
 210                                 nextdev = prevdev->next;
 211
 212                         /*
 213                          * Are we at the end of the list?
 214                          */
 215                         if (nextdev == NULL) {
 216                                 /*
 217                                  * Yes - we have to put the new entry
 218                                  * after "prevdev".
 219                                  */
 220                                 break;
 221                         }
 222
 223                         /*
 224                          * Is the new interface a non-loopback interface
 225                          * and the next interface a loopback interface?
 226                          */
 227                         if (!(curdev->flags & PCAP_IF_LOOPBACK) &&
 228                             (nextdev->flags & PCAP_IF_LOOPBACK)) {
 229                                 /*
 230                                  * Yes, we should put the new entry
 231                                  * before "nextdev", i.e. after "prevdev".
 232                                  */
 233                                 break;
 234                         }
 235
 236                         /*
 237                          * Is the new interface's instance number less
 238                          * than the next interface's instance number,
 239                          * and is it the case that the new interface is a
 240                          * non-loopback interface or the next interface is
 241                          * a loopback interface?
 242                          *
 243                          * (The goal of both loopback tests is to make
 244                          * sure that we never put a loopback interface
 245                          * before any non-loopback interface and that we
 246                          * always put a non-loopback interface before all
 247                          * loopback interfaces.)
 248                          */
 249                         if (this_instance < get_instance(nextdev->name) &&
 250                             (!(curdev->flags & PCAP_IF_LOOPBACK) ||
 251                                (nextdev->flags & PCAP_IF_LOOPBACK))) {
 252                                 /*
 253                                  * Yes - we should put the new entry
 254                                  * before "nextdev", i.e. after "prevdev".
 255                                  */
 256                                 break;
 257                         }
 258
 259                         prevdev = nextdev;
 260                 }
 261
 262                 /*
 263                  * Insert before "nextdev".
 264                  */
 265                 curdev->next = nextdev;
 266
 267                 /*
 268                  * Insert after "prevdev" - unless "prevdev" is null,
 269                  * in which case this is the first interface.
 270                  */
 271                 if (prevdev == NULL) {
 272                         /*
 273                          * This is the first interface.  Pass back a
 274                          * pointer to it, and put "curdev" before
 275                          * "nextdev".
 276                          */
 277                         *alldevs = curdev;
 278                 } else
 279                         prevdev->next = curdev;
 280         }
 281
 282         *curdev_ret = curdev;
 283         return (0);
 284 }
 285
 286 int
 287 add_addr_to_iflist(pcap_if_t **alldevs, char *name, u_int flags,
 288     struct sockaddr *addr, size_t addr_size,
 289     struct sockaddr *netmask, size_t netmask_size,
 290     struct sockaddr *broadaddr, size_t broadaddr_size,
 291     struct sockaddr *dstaddr, size_t dstaddr_size,
 292     char *errbuf)
 293 {
 294         pcap_if_t *curdev;
 295         pcap_addr_t *curaddr, *prevaddr, *nextaddr;
 296
 297         if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) {
 298                 /*
 299                  * Error - give up.
 300                  */
 301                 return (-1);
 302         }
 303         if (curdev == NULL) {
 304                 /*
 305                  * Device wasn't added because it can't be opened.
 306                  * Not a fatal error.
 307                  */
 308                 return (0);
 309         }
 310
 311         /*
 312          * "curdev" is an entry for this interface; add an entry for this
 313          * address to its list of addresses.
 314          *
 315          * Allocate the new entry and fill it in.
 316          */
 317         curaddr = malloc(sizeof(pcap_addr_t));
 318         if (curaddr == NULL) {
 319                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 320                     "malloc: %s", pcap_strerror(errno));
 321                 return (-1);
 322         }
 323
 324         curaddr->next = NULL;
 325         if (addr != NULL) {
 326                 curaddr->addr = dup_sockaddr(addr, addr_size);
 327                 if (curaddr->addr == NULL) {
 328                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 329                             "malloc: %s", pcap_strerror(errno));
 330                         free(curaddr);
 331                         return (-1);
 332                 }
 333         } else
 334                 curaddr->addr = NULL;
 335
 336         if (netmask != NULL) {
 337                 curaddr->netmask = dup_sockaddr(netmask, netmask_size);
 338                 if (curaddr->netmask == NULL) {
 339                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 340                             "malloc: %s", pcap_strerror(errno));
 341                         free(curaddr);
 342                         return (-1);
 343                 }
 344         } else
 345                 curaddr->netmask = NULL;
 346
 347         if (broadaddr != NULL) {
 348                 curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size);
 349                 if (curaddr->broadaddr == NULL) {
 350                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 351                             "malloc: %s", pcap_strerror(errno));
 352                         free(curaddr);
 353                         return (-1);
 354                 }
 355         } else
 356                 curaddr->broadaddr = NULL;
 357
 358         if (dstaddr != NULL) {
 359                 curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size);
 360                 if (curaddr->dstaddr == NULL) {
 361                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 362                             "malloc: %s", pcap_strerror(errno));
 363                         free(curaddr);
 364                         return (-1);
 365                 }
 366         } else
 367                 curaddr->dstaddr = NULL;
 368
 369         /*
 370          * Find the end of the list of addresses.
 371          */
 372         for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) {
 373                 nextaddr = prevaddr->next;
 374                 if (nextaddr == NULL) {
 375                         /*
 376                          * This is the end of the list.
 377                          */
 378                         break;
 379                 }
 380         }
 381
 382         if (prevaddr == NULL) {
 383                 /*
 384                  * The list was empty; this is the first member.
 385                  */
 386                 curdev->addresses = curaddr;
 387         } else {
 388                 /*
 389                  * "prevaddr" is the last member of the list; append
 390                  * this member to it.
 391                  */
 392                 prevaddr->next = curaddr;
 393         }
 394
 395         return (0);
 396 }
 397
 398 int
 399 pcap_add_if(pcap_if_t **devlist, char *name, u_int flags,
 400     const char *description, char *errbuf)
 401 {
 402         pcap_if_t *curdev;
 403
 404         return (add_or_find_if(&curdev, devlist, name, flags, description,
 405             errbuf));
 406 }
 407
 408
 409 /*
 410  * Free a list of interfaces.
 411  */
 412 void
 413 pcap_freealldevs(pcap_if_t *alldevs)
 414 {
 415         pcap_if_t *curdev, *nextdev;
 416         pcap_addr_t *curaddr, *nextaddr;
 417
 418         for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
 419                 nextdev = curdev->next;
 420
 421                 /*
 422                  * Free all addresses.
 423                  */
 424                 for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) {
 425                         nextaddr = curaddr->next;
 426                         if (curaddr->addr)
 427                                 free(curaddr->addr);
 428                         if (curaddr->netmask)
 429                                 free(curaddr->netmask);
 430                         if (curaddr->broadaddr)
 431                                 free(curaddr->broadaddr);
 432                         if (curaddr->dstaddr)
 433                                 free(curaddr->dstaddr);
 434                         free(curaddr);
 435                 }
 436
 437                 /*
 438                  * Free the name string.
 439                  */
 440                 free(curdev->name);
 441
 442                 /*
 443                  * Free the description string, if any.
 444                  */
 445                 if (curdev->description != NULL)
 446                         free(curdev->description);
 447
 448                 /*
 449                  * Free the interface.
 450                  */
 451                 free(curdev);
 452         }
 453 }
 454
 455 #ifndef WIN32
 456
 457 /*
 458  * Return the name of a network interface attached to the system, or NULL
 459  * if none can be found.  The interface must be configured up; the
 460  * lowest unit number is preferred; loopback is ignored.
 461  */
 462 char *
 463 pcap_lookupdev(errbuf)
 464         register char *errbuf;
 465 {
 466         pcap_if_t *alldevs;
 467 /* for old BSD systems, including bsdi3 */
 468 #ifndef IF_NAMESIZE
 469 #define IF_NAMESIZE IFNAMSIZ
 470 #endif
 471         static char device[IF_NAMESIZE + 1];
 472         char *ret;
 473
 474         if (pcap_findalldevs(&alldevs, errbuf) == -1)
 475                 return (NULL);
 476
 477         if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) {
 478                 /*
 479                  * There are no devices on the list, or the first device
 480                  * on the list is a loopback device, which means there
 481                  * are no non-loopback devices on the list.  This means
 482                  * we can't return any device.
 483                  *
 484                  * XXX - why not return a loopback device?  If we can't
 485                  * capture on it, it won't be on the list, and if it's
 486                  * on the list, there aren't any non-loopback devices,
 487                  * so why not just supply it as the default device?
 488                  */
 489                 (void)strlcpy(errbuf, "no suitable device found",
 490                     PCAP_ERRBUF_SIZE);
 491                 ret = NULL;
 492         } else {
 493                 /*
 494                  * Return the name of the first device on the list.
 495                  */
 496                 (void)strlcpy(device, alldevs->name, sizeof(device));
 497                 ret = device;
 498         }
 499
 500         pcap_freealldevs(alldevs);
 501         return (ret);
 502 }
 503
 504 int
 505 pcap_lookupnet(device, netp, maskp, errbuf)
 506         register char *device;
 507         register bpf_u_int32 *netp, *maskp;
 508         register char *errbuf;
 509 {
 510         register int fd;
 511         register struct sockaddr_in *sin;
 512         struct ifreq ifr;
 513
 514         /*
 515          * The pseudo-device "any" listens on all interfaces and therefore
 516          * has the network address and -mask "0.0.0.0" therefore catching
 517          * all traffic. Using NULL for the interface is the same as "any".
 518          */
 519         if (!device || strcmp(device, "any") == 0) {
 520                 *netp = *maskp = 0;
 521                 return 0;
 522         }
 523
 524         fd = socket(AF_INET, SOCK_DGRAM, 0);
 525         if (fd < 0) {
 526                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
 527                     pcap_strerror(errno));
 528                 return (-1);
 529         }
 530         memset(&ifr, 0, sizeof(ifr));
 531 #ifdef linux
 532         /* XXX Work around Linux kernel bug */
 533         ifr.ifr_addr.sa_family = AF_INET;
 534 #endif
 535         (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
 536         if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
 537                 if (errno == EADDRNOTAVAIL) {
 538                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 539                             "%s: no IPv4 address assigned", device);
 540                 } else {
 541                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 542                             "SIOCGIFADDR: %s: %s",
 543                             device, pcap_strerror(errno));
 544                 }
 545                 (void)close(fd);
 546                 return (-1);
 547         }
 548         sin = (struct sockaddr_in *)&ifr.ifr_addr;
 549         *netp = sin->sin_addr.s_addr;
 550         if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
 551                 (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 552                     "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
 553                 (void)close(fd);
 554                 return (-1);
 555         }
 556         (void)close(fd);
 557         *maskp = sin->sin_addr.s_addr;
 558         if (*maskp == 0) {
 559                 if (IN_CLASSA(*netp))
 560                         *maskp = IN_CLASSA_NET;
 561                 else if (IN_CLASSB(*netp))
 562                         *maskp = IN_CLASSB_NET;
 563                 else if (IN_CLASSC(*netp))
 564                         *maskp = IN_CLASSC_NET;
 565                 else {
 566                         (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
 567                             "inet class for 0x%x unknown", *netp);
 568                         return (-1);
 569                 }
 570         }
 571         *netp &= *maskp;
 572         return (0);
 573 }
 574
 575 #else /* WIN32 */
 576
 577 /*
 578  * Return the name of a network interface attached to the system, or NULL
 579  * if none can be found.  The interface must be configured up; the
 580  * lowest unit number is preferred; loopback is ignored.
 581  */
 582 char *
 583 pcap_lookupdev(errbuf)
 584         register char *errbuf;
 585 {
 586         DWORD dwVersion;
 587         DWORD dwWindowsMajorVersion;
 588         dwVersion = GetVersion();       /* get the OS version */
 589         dwWindowsMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
 590
 591         if (dwVersion >= 0x80000000 && dwWindowsMajorVersion >= 4) {
 592                 /*
 593                  * Windows 95, 98, ME.
 594                  */
 595                 ULONG NameLength = 8192;
 596                 static char AdaptersName[8192];
 597
 598                 PacketGetAdapterNames(AdaptersName,&NameLength);
 599
 600                 return (AdaptersName);
 601         } else {
 602                 /*
 603                  * Windows NT (NT 4.0, W2K, WXP).
 604                  */
 605                 ULONG NameLength = 8192;
 606                 static WCHAR AdaptersName[8192];
 607
 608                 PacketGetAdapterNames((PTSTR)AdaptersName,&NameLength);
 609
 610                 return (char *)(AdaptersName);
 611         }
 612 }
 613
 614
 615 int
 616 pcap_lookupnet(device, netp, maskp, errbuf)
 617         register char *device;
 618         register bpf_u_int32 *netp, *maskp;
 619         register char *errbuf;
 620 {
 621         /*
 622          * We need only the first address, so we allocate a single
 623          * npf_if_addr structure and we set if_addr_size to 1.
 624          */
 625         npf_if_addr if_addrs;
 626         LONG if_addr_size = 1;
 627         struct sockaddr_in *t_addr;
 628
 629         if (!PacketGetNetInfoEx((void *)device, &if_addrs, &if_addr_size)) {
 630                 *netp = *maskp = 0;
 631                 return (0);
 632         }
 633
 634         t_addr = (struct sockaddr_in *) &(if_addrs.IPAddress);
 635         *netp = t_addr->sin_addr.S_un.S_addr;
 636         t_addr = (struct sockaddr_in *) &(if_addrs.SubnetMask);
 637         *maskp = t_addr->sin_addr.S_un.S_addr;
 638
 639         /*
 640          * XXX - will we ever get back a 0 netmask?
 641          * If so, we should presumably make the "if (*maskp == 0)" code
 642          * above common, rather than non-Win32-specific.
 643          */
 644
 645         *netp &= *maskp;
 646         return (0);
 647 }
 648
 649 #endif /* WIN32 */