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inet.c

/* -*- Mode: c; tab-width: 8; indent-tabs-mode: 1; c-basic-offset: 8; -*- */
/*
 * Copyright (c) 1994, 1995, 1996, 1997, 1998
 *    The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *    This product includes software developed by the Computer Systems
 *    Engineering Group at Lawrence Berkeley Laboratory.
 * 4. Neither the name of the University nor of the Laboratory may be used
 *    to endorse or promote products derived from this software without
 *    specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#ifndef lint
static const char rcsid[] _U_ =
    "@(#) $Header: /tcpdump/master/libpcap/inet.c,v 1.66.2.6 2007/06/11 09:52:04 guy Exp $ (LBL)";
#endif

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#ifdef WIN32
#include <pcap-stdinc.h>
#else /* WIN32 */

#include <sys/param.h>
#ifndef MSDOS
#include <sys/file.h>
#endif
#include <sys/ioctl.h>
#include <sys/socket.h>
#ifdef HAVE_SYS_SOCKIO_H
#include <sys/sockio.h>
#endif

struct mbuf;            /* Squelch compiler warnings on some platforms for */
struct rtentry;         /* declarations in <net/if.h> */
#include <net/if.h>
#include <netinet/in.h>
#endif /* WIN32 */

#include <ctype.h>
#include <errno.h>
#include <memory.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#if !defined(WIN32) && !defined(__BORLANDC__)
#include <unistd.h>
#endif /* !WIN32 && !__BORLANDC__ */
#ifdef HAVE_LIMITS_H
#include <limits.h>
#else
#define INT_MAX         2147483647
#endif

#include "pcap-int.h"

#ifdef HAVE_OS_PROTO_H
#include "os-proto.h"
#endif

/* Not all systems have IFF_LOOPBACK */
#ifdef IFF_LOOPBACK
#define ISLOOPBACK(name, flags) ((flags) & IFF_LOOPBACK)
#else
#define ISLOOPBACK(name, flags) ((name)[0] == 'l' && (name)[1] == 'o' && \
    (isdigit((unsigned char)((name)[2])) || (name)[2] == '\0'))
#endif

struct sockaddr *
dup_sockaddr(struct sockaddr *sa, size_t sa_length)
{
      struct sockaddr *newsa;

      if ((newsa = malloc(sa_length)) == NULL)
            return (NULL);
      return (memcpy(newsa, sa, sa_length));
}

static int
get_instance(const char *name)
{
      const char *cp, *endcp;
      int n;

      if (strcmp(name, "any") == 0) {
            /*
             * Give the "any" device an artificially high instance
             * number, so it shows up after all other non-loopback
             * interfaces.
             */
            return INT_MAX;
      }

      endcp = name + strlen(name);
      for (cp = name; cp < endcp && !isdigit((unsigned char)*cp); ++cp)
            continue;

      if (isdigit((unsigned char)*cp))
            n = atoi(cp);
      else
            n = 0;
      return (n);
}

int
add_or_find_if(pcap_if_t **curdev_ret, pcap_if_t **alldevs, const char *name,
    u_int flags, const char *description, char *errbuf)
{
      pcap_t *p;
      pcap_if_t *curdev, *prevdev, *nextdev;
      int this_instance;

      /*
       * Is there already an entry in the list for this interface?
       */
      for (curdev = *alldevs; curdev != NULL; curdev = curdev->next) {
            if (strcmp(name, curdev->name) == 0)
                  break;      /* yes, we found it */
      }

      if (curdev == NULL) {
            /*
             * No, we didn't find it.
             *
             * Can we open this interface for live capture?
             *
             * We do this check so that interfaces that are
             * supplied by the interface enumeration mechanism
             * we're using but that don't support packet capture
             * aren't included in the list.  Loopback interfaces
             * on Solaris are an example of this; we don't just
             * omit loopback interfaces on all platforms because
             * you *can* capture on loopback interfaces on some
             * OSes.
             *
             * On OS X, we don't do this check if the device
             * name begins with "wlt"; at least some versions
             * of OS X offer monitor mode capturing by having
             * a separate "monitor mode" device for each wireless
             * adapter, rather than by implementing the ioctls
             * that {Free,Net,Open,DragonFly}BSD provide.
             * Opening that device puts the adapter into monitor
             * mode, which, at least for some adapters, causes
             * them to deassociate from the network with which
             * they're associated.
             *
             * Instead, we try to open the corresponding "en"
             * device (so that we don't end up with, for users
             * without sufficient privilege to open capture
             * devices, a list of adapters that only includes
             * the wlt devices).
             */
#ifdef __APPLE__
            if (strncmp(name, "wlt", 3) == 0) {
                  char *en_name;
                  size_t en_name_len;

                  /*
                   * Try to allocate a buffer for the "en"
                   * device's name.
                   */
                  en_name_len = strlen(name) - 1;
                  en_name = malloc(en_name_len + 1);
                  if (en_name == NULL) {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "malloc: %s", pcap_strerror(errno));
                        return (-1);
                  }
                  strcpy(en_name, "en");
                  strcat(en_name, name + 3);
                  p = pcap_open_live(en_name, 68, 0, 0, errbuf);
                  free(en_name);
            } else
#endif /* __APPLE */
            p = pcap_open_live(name, 68, 0, 0, errbuf);
            if (p == NULL) {
                  /*
                   * No.  Don't bother including it.
                   * Don't treat this as an error, though.
                   */
                  *curdev_ret = NULL;
                  return (0);
            }
            pcap_close(p);

            /*
             * Yes, we can open it.
             * Allocate a new entry.
             */
            curdev = malloc(sizeof(pcap_if_t));
            if (curdev == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  return (-1);
            }

            /*
             * Fill in the entry.
             */
            curdev->next = NULL;
            curdev->name = strdup(name);
            if (curdev->name == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  free(curdev);
                  return (-1);
            }
            if (description != NULL) {
                  /*
                   * We have a description for this interface.
                   */
                  curdev->description = strdup(description);
                  if (curdev->description == NULL) {
                        (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                            "malloc: %s", pcap_strerror(errno));
                        free(curdev->name);
                        free(curdev);
                        return (-1);
                  }
            } else {
                  /*
                   * We don't.
                   */
                  curdev->description = NULL;
            }
            curdev->addresses = NULL;     /* list starts out as empty */
            curdev->flags = 0;
            if (ISLOOPBACK(name, flags))
                  curdev->flags |= PCAP_IF_LOOPBACK;

            /*
             * Add it to the list, in the appropriate location.
             * First, get the instance number of this interface.
             */
            this_instance = get_instance(name);

            /*
             * Now look for the last interface with an instance number
             * less than or equal to the new interface's instance
             * number - except that non-loopback interfaces are
             * arbitrarily treated as having interface numbers less
             * than those of loopback interfaces, so the loopback
             * interfaces are put at the end of the list.
             *
             * We start with "prevdev" being NULL, meaning we're before
             * the first element in the list.
             */
            prevdev = NULL;
            for (;;) {
                  /*
                   * Get the interface after this one.
                   */
                  if (prevdev == NULL) {
                        /*
                         * The next element is the first element.
                         */
                        nextdev = *alldevs;
                  } else
                        nextdev = prevdev->next;

                  /*
                   * Are we at the end of the list?
                   */
                  if (nextdev == NULL) {
                        /*
                         * Yes - we have to put the new entry
                         * after "prevdev".
                         */
                        break;
                  }

                  /*
                   * Is the new interface a non-loopback interface
                   * and the next interface a loopback interface?
                   */
                  if (!(curdev->flags & PCAP_IF_LOOPBACK) &&
                      (nextdev->flags & PCAP_IF_LOOPBACK)) {
                        /*
                         * Yes, we should put the new entry
                         * before "nextdev", i.e. after "prevdev".
                         */
                        break;
                  }

                  /*
                   * Is the new interface's instance number less
                   * than the next interface's instance number,
                   * and is it the case that the new interface is a
                   * non-loopback interface or the next interface is
                   * a loopback interface?
                   *
                   * (The goal of both loopback tests is to make
                   * sure that we never put a loopback interface
                   * before any non-loopback interface and that we
                   * always put a non-loopback interface before all
                   * loopback interfaces.)
                   */
                  if (this_instance < get_instance(nextdev->name) &&
                      (!(curdev->flags & PCAP_IF_LOOPBACK) ||
                         (nextdev->flags & PCAP_IF_LOOPBACK))) {
                        /*
                         * Yes - we should put the new entry
                         * before "nextdev", i.e. after "prevdev".
                         */
                        break;
                  }

                  prevdev = nextdev;
            }

            /*
             * Insert before "nextdev".
             */
            curdev->next = nextdev;

            /*
             * Insert after "prevdev" - unless "prevdev" is null,
             * in which case this is the first interface.
             */
            if (prevdev == NULL) {
                  /*
                   * This is the first interface.  Pass back a
                   * pointer to it, and put "curdev" before
                   * "nextdev".
                   */
                  *alldevs = curdev;
            } else
                  prevdev->next = curdev;
      }

      *curdev_ret = curdev;
      return (0);
}

int
add_addr_to_iflist(pcap_if_t **alldevs, const char *name, u_int flags,
    struct sockaddr *addr, size_t addr_size,
    struct sockaddr *netmask, size_t netmask_size,
    struct sockaddr *broadaddr, size_t broadaddr_size,
    struct sockaddr *dstaddr, size_t dstaddr_size,
    char *errbuf)
{
      pcap_if_t *curdev;
      pcap_addr_t *curaddr, *prevaddr, *nextaddr;

      if (add_or_find_if(&curdev, alldevs, name, flags, NULL, errbuf) == -1) {
            /*
             * Error - give up.
             */
            return (-1);
      }
      if (curdev == NULL) {
            /*
             * Device wasn't added because it can't be opened.
             * Not a fatal error.
             */
            return (0);
      }

      /*
       * "curdev" is an entry for this interface; add an entry for this
       * address to its list of addresses.
       *
       * Allocate the new entry and fill it in.
       */
      curaddr = malloc(sizeof(pcap_addr_t));
      if (curaddr == NULL) {
            (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                "malloc: %s", pcap_strerror(errno));
            return (-1);
      }

      curaddr->next = NULL;
      if (addr != NULL) {
            curaddr->addr = dup_sockaddr(addr, addr_size);
            if (curaddr->addr == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  free(curaddr);
                  return (-1);
            }
      } else
            curaddr->addr = NULL;

      if (netmask != NULL) {
            curaddr->netmask = dup_sockaddr(netmask, netmask_size);
            if (curaddr->netmask == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  if (curaddr->addr != NULL)
                        free(curaddr->addr);
                  free(curaddr);
                  return (-1);
            }
      } else
            curaddr->netmask = NULL;

      if (broadaddr != NULL) {
            curaddr->broadaddr = dup_sockaddr(broadaddr, broadaddr_size);
            if (curaddr->broadaddr == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  if (curaddr->netmask != NULL)
                        free(curaddr->netmask);
                  if (curaddr->addr != NULL)
                        free(curaddr->addr);
                  free(curaddr);
                  return (-1);
            }
      } else
            curaddr->broadaddr = NULL;

      if (dstaddr != NULL) {
            curaddr->dstaddr = dup_sockaddr(dstaddr, dstaddr_size);
            if (curaddr->dstaddr == NULL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "malloc: %s", pcap_strerror(errno));
                  if (curaddr->broadaddr != NULL)
                        free(curaddr->broadaddr);
                  if (curaddr->netmask != NULL)
                        free(curaddr->netmask);
                  if (curaddr->addr != NULL)
                        free(curaddr->addr);
                  free(curaddr);
                  return (-1);
            }
      } else
            curaddr->dstaddr = NULL;

      /*
       * Find the end of the list of addresses.
       */
      for (prevaddr = curdev->addresses; prevaddr != NULL; prevaddr = nextaddr) {
            nextaddr = prevaddr->next;
            if (nextaddr == NULL) {
                  /*
                   * This is the end of the list.
                   */
                  break;
            }
      }

      if (prevaddr == NULL) {
            /*
             * The list was empty; this is the first member.
             */
            curdev->addresses = curaddr;
      } else {
            /*
             * "prevaddr" is the last member of the list; append
             * this member to it.
             */
            prevaddr->next = curaddr;
      }

      return (0);
}

int
pcap_add_if(pcap_if_t **devlist, const char *name, u_int flags,
    const char *description, char *errbuf)
{
      pcap_if_t *curdev;

      return (add_or_find_if(&curdev, devlist, name, flags, description,
          errbuf));
}


/*
 * Free a list of interfaces.
 */
void
pcap_freealldevs(pcap_if_t *alldevs)
{
      pcap_if_t *curdev, *nextdev;
      pcap_addr_t *curaddr, *nextaddr;

      for (curdev = alldevs; curdev != NULL; curdev = nextdev) {
            nextdev = curdev->next;

            /*
             * Free all addresses.
             */
            for (curaddr = curdev->addresses; curaddr != NULL; curaddr = nextaddr) {
                  nextaddr = curaddr->next;
                  if (curaddr->addr)
                        free(curaddr->addr);
                  if (curaddr->netmask)
                        free(curaddr->netmask);
                  if (curaddr->broadaddr)
                        free(curaddr->broadaddr);
                  if (curaddr->dstaddr)
                        free(curaddr->dstaddr);
                  free(curaddr);
            }

            /*
             * Free the name string.
             */
            free(curdev->name);

            /*
             * Free the description string, if any.
             */
            if (curdev->description != NULL)
                  free(curdev->description);

            /*
             * Free the interface.
             */
            free(curdev);
      }
}

#if !defined(WIN32) && !defined(MSDOS)

/*
 * Return the name of a network interface attached to the system, or NULL
 * if none can be found.  The interface must be configured up; the
 * lowest unit number is preferred; loopback is ignored.
 */
char *
pcap_lookupdev(errbuf)
      register char *errbuf;
{
      pcap_if_t *alldevs;
/* for old BSD systems, including bsdi3 */
#ifndef IF_NAMESIZE
#define IF_NAMESIZE IFNAMSIZ
#endif
      static char device[IF_NAMESIZE + 1];
      char *ret;

      if (pcap_findalldevs(&alldevs, errbuf) == -1)
            return (NULL);

      if (alldevs == NULL || (alldevs->flags & PCAP_IF_LOOPBACK)) {
            /*
             * There are no devices on the list, or the first device
             * on the list is a loopback device, which means there
             * are no non-loopback devices on the list.  This means
             * we can't return any device.
             *
             * XXX - why not return a loopback device?  If we can't
             * capture on it, it won't be on the list, and if it's
             * on the list, there aren't any non-loopback devices,
             * so why not just supply it as the default device?
             */
            (void)strlcpy(errbuf, "no suitable device found",
                PCAP_ERRBUF_SIZE);
            ret = NULL;
      } else {
            /*
             * Return the name of the first device on the list.
             */
            (void)strlcpy(device, alldevs->name, sizeof(device));
            ret = device;
      }

      pcap_freealldevs(alldevs);
      return (ret);
}

int
pcap_lookupnet(device, netp, maskp, errbuf)
      register const char *device;
      register bpf_u_int32 *netp, *maskp;
      register char *errbuf;
{
      register int fd;
      register struct sockaddr_in *sin4;
      struct ifreq ifr;

      /*
       * The pseudo-device "any" listens on all interfaces and therefore
       * has the network address and -mask "0.0.0.0" therefore catching
       * all traffic. Using NULL for the interface is the same as "any".
       */
      if (!device || strcmp(device, "any") == 0
#ifdef HAVE_DAG_API
          || strstr(device, "dag") != NULL
#endif
#ifdef HAVE_SEPTEL_API
          || strstr(device, "septel") != NULL
#endif
          ) {
            *netp = *maskp = 0;
            return 0;
      }

      fd = socket(AF_INET, SOCK_DGRAM, 0);
      if (fd < 0) {
            (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "socket: %s",
                pcap_strerror(errno));
            return (-1);
      }
      memset(&ifr, 0, sizeof(ifr));
#ifdef linux
      /* XXX Work around Linux kernel bug */
      ifr.ifr_addr.sa_family = AF_INET;
#endif
      (void)strncpy(ifr.ifr_name, device, sizeof(ifr.ifr_name));
      if (ioctl(fd, SIOCGIFADDR, (char *)&ifr) < 0) {
            if (errno == EADDRNOTAVAIL) {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "%s: no IPv4 address assigned", device);
            } else {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "SIOCGIFADDR: %s: %s",
                      device, pcap_strerror(errno));
            }
            (void)close(fd);
            return (-1);
      }
      sin4 = (struct sockaddr_in *)&ifr.ifr_addr;
      *netp = sin4->sin_addr.s_addr;
      if (ioctl(fd, SIOCGIFNETMASK, (char *)&ifr) < 0) {
            (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                "SIOCGIFNETMASK: %s: %s", device, pcap_strerror(errno));
            (void)close(fd);
            return (-1);
      }
      (void)close(fd);
      *maskp = sin4->sin_addr.s_addr;
      if (*maskp == 0) {
            if (IN_CLASSA(*netp))
                  *maskp = IN_CLASSA_NET;
            else if (IN_CLASSB(*netp))
                  *maskp = IN_CLASSB_NET;
            else if (IN_CLASSC(*netp))
                  *maskp = IN_CLASSC_NET;
            else {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                      "inet class for 0x%x unknown", *netp);
                  return (-1);
            }
      }
      *netp &= *maskp;
      return (0);
}

#elif defined(WIN32)

/*
 * Return the name of a network interface attached to the system, or NULL
 * if none can be found.  The interface must be configured up; the
 * lowest unit number is preferred; loopback is ignored.
 */
char *
pcap_lookupdev(errbuf)
      register char *errbuf;
{
      DWORD dwVersion;
      DWORD dwWindowsMajorVersion;
      dwVersion = GetVersion();     /* get the OS version */
      dwWindowsMajorVersion = (DWORD)(LOBYTE(LOWORD(dwVersion)));
      
      if (dwVersion >= 0x80000000 && dwWindowsMajorVersion >= 4) {
            /*
             * Windows 95, 98, ME.
             */
            ULONG NameLength = 8192;
            static char AdaptersName[8192];
            
            if (PacketGetAdapterNames(AdaptersName,&NameLength) )
                  return (AdaptersName);
            else
                  return NULL;
      } else {
            /*
             * Windows NT (NT 4.0, W2K, WXP). Convert the names to UNICODE for backward compatibility
             */
            ULONG NameLength = 8192;
            static WCHAR AdaptersName[8192];
            char *tAstr;
            WCHAR *tUstr;
            WCHAR *TAdaptersName = (WCHAR*)malloc(8192 * sizeof(WCHAR));
            int NAdapts = 0;

            if(TAdaptersName == NULL)
            {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE, "memory allocation failure");
                  return NULL;
            }

            if ( !PacketGetAdapterNames((PTSTR)TAdaptersName,&NameLength) )
            {
                  (void)snprintf(errbuf, PCAP_ERRBUF_SIZE,
                        "PacketGetAdapterNames: %s",
                        pcap_win32strerror());
                  free(TAdaptersName);
                  return NULL;
            }


            tAstr = (char*)TAdaptersName;
            tUstr = (WCHAR*)AdaptersName;

            /*
             * Convert and copy the device names
             */
            while(sscanf(tAstr, "%S", tUstr) > 0)
            {
                  tAstr += strlen(tAstr) + 1;
                  tUstr += wcslen(tUstr) + 1;
                  NAdapts ++;
            }

            tAstr++;
            *tUstr = 0;
            tUstr++;

            /*
             * Copy the descriptions
             */
            while(NAdapts--)
            {
                  strcpy((char*)tUstr, tAstr);
                  (char*)tUstr += strlen(tAstr) + 1;;
                  tAstr += strlen(tAstr) + 1;
            }

            free(TAdaptersName);
            return (char *)(AdaptersName);
      }     
}


int
pcap_lookupnet(device, netp, maskp, errbuf)
      register const char *device;
      register bpf_u_int32 *netp, *maskp;
      register char *errbuf;
{
      /* 
       * We need only the first IPv4 address, so we must scan the array returned by PacketGetNetInfo()
       * in order to skip non IPv4 (i.e. IPv6 addresses)
       */
      npf_if_addr if_addrs[MAX_NETWORK_ADDRESSES];
      LONG if_addr_size = 1;
      struct sockaddr_in *t_addr;
      unsigned int i;

      if (!PacketGetNetInfoEx((void *)device, if_addrs, &if_addr_size)) {
            *netp = *maskp = 0;
            return (0);
      }

      for(i=0; i<MAX_NETWORK_ADDRESSES; i++)
      {
            if(if_addrs[i].IPAddress.ss_family == AF_INET)
            {
                  t_addr = (struct sockaddr_in *) &(if_addrs[i].IPAddress);
                  *netp = t_addr->sin_addr.S_un.S_addr;
                  t_addr = (struct sockaddr_in *) &(if_addrs[i].SubnetMask);
                  *maskp = t_addr->sin_addr.S_un.S_addr;

                  *netp &= *maskp;
                  return (0);
            }
                        
      }

      *netp = *maskp = 0;
      return (0);
}

#endif /* !WIN32 && !MSDOS */

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