ec_inet_macosx.c

Ettercap最初设计为交换网上的sniffer

/*
    ettercap -- inet utilities -- Module for MacOsX darwin 1.[34]
                                                    darwin 5.[012]

    Copyright (C) 2001  ALoR <[e-mail]>, NaGA <[e-mail]>

    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

    $Id: ec_inet_macosx.c,v 1.14 2002/06/12 16:19:38 alor Exp $
*/

#include "../../include/ec_main.h"

#include "../../include/ec_thread.h"
#include "../../include/ec_buffer.h"
#include "../../include/ec_inet.h"
#include "../../include/ec_inet_forge.h"
#include "../../include/ec_inet_structures.h"

#include <ctype.h>
#include <sys/ioctl.h>
#include <fcntl.h>

#include <sys/sysctl.h>
#include <sys/param.h>
#include <sys/timeb.h>
#include <sys/file.h>
#include <sys/ioctl.h>
#include <ctype.h>

#include <sys/types.h>
#include <sys/time.h>
#include <net/bpf.h>

#include <sys/socket.h>
#include <net/if_dl.h>
#include <net/route.h>
#include <net/if_types.h>
#include <arpa/inet.h>

#include <netinet/if_ether.h>
#ifdef HAVE_NET_ETHERNET_H
   #include <net/ethernet.h>
#endif


int IpForward_status;      // old ipforward status

int bpf_in_use;
int size;
int SocketBuffer = -1;

static char ARP_BROADCAST[6] = {0x0,0x0,0x0,0x0,0x0,0x0};

// protos...

int Inet_FindIFace(char *iface);
int Inet_CorrectIface(char *iface);
int Inet_GetIfaceInfo(char *iface, int *MTU, char *MyMAC, u_long *IP, u_long *NetMask);
int Inet_SetPromisc(char *iface);
int Inet_OpenRawSock(char *iface);
void Inet_CloseRawSock(int sock);
int Inet_GetRawPacket(int sock, char *buffer, int MTU, short *type);
int Inet_SendRawPacket(int sock, char *buffer, int len);
void Inet_SetNonBlock(int sock);
void Inet_Restore_ifr(void);
void Inet_DisableForwarding(void);
void Inet_RestoreForwarding(void);
char *Inet_MacFromIP(unsigned long ip);


// ----------------------------------------------

int Inet_FindIFace(char *iface)     // adapded from pcap_lookupdev
{
   int fd, minunit, n;
   char *cp;
   struct ifreq *ifrp, *ifend, *ifnext, *mp;
   struct ifconf ifc;
   char *buf;
   struct ifreq ifr;
   unsigned int buf_size;

   fd = socket(AF_INET, SOCK_DGRAM, 0);
   if (fd < 0)
      ERROR_MSG("socket()");

   buf_size = 8192;

   for (;;) {
      buf = malloc (buf_size);
      if (buf == NULL)
         ERROR_MSG("malloc()");

      ifc.ifc_len = buf_size;
      ifc.ifc_buf = buf;
      memset (buf, 0, buf_size);
      if (ioctl(fd, SIOCGIFCONF, (char *)&ifc) < 0 && errno != EINVAL)
         ERROR_MSG("ioctl(SIOCGIFCONF)");

      if (ifc.ifc_len < buf_size)
         break;

      free (buf);
      buf_size *= 2;
   }

   ifrp = (struct ifreq *)buf;
   ifend = (struct ifreq *)(buf + ifc.ifc_len);

   mp = NULL;
   minunit = 666;
   for (; ifrp < ifend; ifrp = ifnext)
   {
      const char *endcp;

#ifdef HAVE_SOCKADDR_SA_LEN
   n = ifrp->ifr_addr.sa_len + sizeof(ifrp->ifr_name);
   if (n < sizeof(*ifrp))
      ifnext = ifrp + 1;
   else
      ifnext = (struct ifreq *)((char *)ifrp + n);
   if (ifrp->ifr_addr.sa_family != AF_INET)
      continue;
#else
   ifnext = ifrp + 1;
#endif

      strncpy(ifr.ifr_name, ifrp->ifr_name, sizeof(ifr.ifr_name));

      if (ioctl(fd, SIOCGIFFLAGS, (char *)&ifr) < 0)
      {
         if (errno == ENXIO)
            continue;
         ERROR_MSG("ioctl(SIOCGIFFLAGS)");
      }

      DEBUG_MSG("Inet_FindIFace -- check for [%s]", ifr.ifr_name);

      /* Must be up and not the loopback */
      if ((ifr.ifr_flags & IFF_UP) == 0 || (ifr.ifr_flags & IFF_LOOPBACK) != 0)
         continue;

      endcp = ifrp->ifr_name + strlen(ifrp->ifr_name);
      for (cp = ifrp->ifr_name; cp < endcp && !isdigit(*cp); ++cp)
         continue;

      if (isdigit (*cp)) {
         n = atoi(cp);
      } else {
         n = 0;
      }
      if (n < minunit) {
         minunit = n;
         mp = ifrp;
      }
   }

   close(fd);

   if (mp == NULL)   // no device found
   {
      free(buf);
      return -1;
   }

   strlcpy(iface, mp->ifr_name, sizeof(Options.netiface));

   free(buf);

   DEBUG_MSG("Inet_FindIFace -- %s found !!", iface);

   return 0;

}


int Inet_CorrectIface(char *iface)
{
   int sock;
   struct ifreq ifr;

   DEBUG_MSG("Inet_CorrectIface\t\tIface: %s", iface);

   sock = socket(AF_INET, SOCK_DGRAM, 0);
   if (sock < 0)
      ERROR_MSG("socket()");

   memset(&ifr, 0, sizeof(ifr));
   strncpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));
   if ( ioctl(sock, SIOCGIFFLAGS, &ifr) < 0)             // check for iface
   {
      close(sock);
      return -1;
   }

   if (!(ifr.ifr_flags & IFF_UP ))                       // check for flag UP
   {
      close(sock);
      return -1;
   }

   if (ifr.ifr_flags & IFF_LOOPBACK )                    // check for loopback
   {
      Options.normal = 1;
      Error_msg("Ettercap can't be run on loopback device");
   }

   if ( ioctl(sock, SIOCGIFADDR, &ifr) < 0 )             // check for alias
   {
      close(sock);
      return -1;
   }

   close(sock);

   return 0;

}



int Inet_GetIfaceInfo(char *iface, int *MTU, char *MyMAC, unsigned long *IP, unsigned long *NetMask)
{
   int sock;
   struct ifreq ifr;

   sock = socket(PF_INET, SOCK_DGRAM, 0);

   memset(&ifr, 0, sizeof(ifr));
   strncpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));

   if (MTU != NULL)
   {
      if ( ioctl(sock, SIOCGIFMTU, &ifr) < 0)
      {
         DEBUG_MSG("Inet_GetIfaceInfo -- MTU FAILED... assuming 1500");
         *MTU = 1500;
      }
      else
         *MTU = ifr.ifr_mtu;
   }

   if (MyMAC != NULL)
   {
      int mib[6];
      size_t len;
      char *buf, *next, *end;
      struct if_msghdr *ifm;
      struct sockaddr_dl *sdl;

      mib[0] = CTL_NET;
      mib[1] = AF_ROUTE;
      mib[2] = 0;
      mib[3] = AF_LINK;
      mib[4] = NET_RT_IFLIST;
      mib[5] = 0;

      if (sysctl(mib, 6, NULL, &len, NULL, 0) < 0)
         ERROR_MSG("sysctl()");

      if ((buf = (char *)malloc(len)) == NULL )
         ERROR_MSG("malloc()");

      if (sysctl(mib, 6, buf, &len, NULL, 0) < 0)
         ERROR_MSG("sysctl()");

      end = buf + len;

      for (next = buf ; next < end ; next += ifm->ifm_msglen)
      {
         ifm = (struct if_msghdr *)next;
         if (ifm->ifm_type == RTM_IFINFO)
         {
            sdl = (struct sockaddr_dl *)(ifm + 1);
            if (strncmp(&sdl->sdl_data[0], iface, sdl->sdl_nlen) == 0)
            {
                memcpy(MyMAC, LLADDR(sdl), ETHER_ADDR_LEN);
                break;
            }
         }
      }

      free(buf);
   }

   if (IP != NULL)
   {
      if ( ioctl(sock, SIOCGIFADDR, &ifr) < 0 )
         ERROR_MSG("ioctl(SIOCGIFADDR)");
      memcpy((char *)IP, ifr.ifr_addr.sa_data+2, 4);
   }

   if (NetMask != NULL)
   {
      if ( ioctl(sock, SIOCGIFNETMASK, &ifr) < 0 )
         ERROR_MSG("ioctl(SIOCGIFNETMASK)");
      memcpy((char *)NetMask, ifr.ifr_addr.sa_data+2, 4);
      if (strcmp(Options.netmask, ""))       // specified on command line
         *NetMask = inet_addr(Options.netmask);
   }

   close(sock);

   return 0;


}


void Inet_SetNonBlock(int sock)
{
   DEBUG_MSG("Inet_SetNonBlock fd = %d", sock);

   fcntl(sock, F_SETFL, O_NONBLOCK);

}


void Inet_CloseRawSock(int sock)
{

   DEBUG_MSG("Inet_CloseRawSock \t wrappered to NULL");

   //close(sock);    // the bpf is close when ettercap exits

}




int Inet_OpenRawSock(char *iface)
{
   int fd, i = 0, type;
   char device[sizeof "/dev/bpf0000"];
   struct bpf_version bv;
   struct ifreq ifr;
   char MyMAC[6];

   // this BPF will ignore all outgoing packets

   static struct bpf_insn insns[] = {
      BPF_STMT(BPF_LD+BPF_H+BPF_ABS, 6),           // load mac address [1][2]
      BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x00, 0, 4), // k is left 0x00 and will be set later... insns[1].k = htons(*(short *)MyMAC);
      BPF_STMT(BPF_LD+BPF_H+BPF_ABS, 8),           // load mac address [3][4]
      BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x00, 0, 2), // if equal check the third part, else jump 2
      BPF_STMT(BPF_LD+BPF_H+BPF_ABS, 10),          // load mac address [5][6]
      BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, 0x00, 1, 0), // if equal this is outgoing ! drop it !
      BPF_STMT(BPF_RET|BPF_K, (u_int)-1),          // no filter, passing the wole packet
      BPF_STMT(BPF_RET|BPF_K, 0),                  // ignore the packet
   };

   static struct bpf_program filter = {
      sizeof insns / sizeof(insns[0]),
      insns
   };