ec_inet_macosx.c

Ettercap最初设计为交换网上的sniffer

#if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)
    u_int spoof_eth_src = 1;
#endif

   if (bpf_in_use != 0) {
      DEBUG_MSG("Inet_OpenRawSock %s", iface);
      DEBUG_MSG("Inet_OpenRawSock \t bpf_in_use = %d ", bpf_in_use);
      return bpf_in_use;
   }

   Inet_GetIfaceInfo(iface, NULL, MyMAC, NULL, NULL);

   insns[1].k = htons(*(short *)MyMAC);         // put MyMac in the filter...
   insns[3].k = htons(*(short *)(MyMAC+2));
   insns[5].k = htons(*(short *)(MyMAC+4));


   DEBUG_MSG("Inet_OpenRawSock %s", iface);


   do    // find an available bpf device
   {
      sprintf(device, "/dev/bpf%d", i++);
      fd = open(device, O_RDWR);
   } while (fd < 0 && errno == EBUSY);

   if (fd < 0)
      Error_msg("ec_inet_macosx:%d  no /dev/bpf* available (tried to open %d) | ERRNO : %d | %s", __LINE__, i, errno, strerror(errno));

   DEBUG_MSG("Inet_OpenRawSock \t fd = %d -- /dev/bpf%d ", fd, i-1);

   if (ioctl(fd, BIOCVERSION, (caddr_t)&bv) < 0)      // get bpf version
      ERROR_MSG(" ioctl(BIOCVERSION)");


   if (bv.bv_major != BPF_MAJOR_VERSION || bv.bv_minor < BPF_MINOR_VERSION)
      Error_msg(" Kernel bpf filter out of date ");

   for (size = 32768; size != 0; size >>= 1)
   {
      ioctl(fd, BIOCSBLEN, (caddr_t)&size);

      strncpy(ifr.ifr_name, iface, sizeof(ifr.ifr_name));    // attach the iface to the bpf
      if (ioctl(fd, BIOCSETIF, (caddr_t)&ifr) >= 0)
         break;  /* that size worked; we're done */

      if (errno != ENOBUFS)
         ERROR_MSG(" ioctl(BIOCSETIF)");
   }

   if (size == 0) Error_msg("BIOCSBLEN: No buffer size worked");

   if (ioctl(fd, BIOCGBLEN, (caddr_t)&size) < 0)
     ERROR_MSG(" ioctl(BIOCGBLEN)");

   if (ioctl(fd, BIOCGDLT, (caddr_t)&type) == -1)           // Get the data link layer type.
      ERROR_MSG(" ioctl(BIOCGDLT)");

   if (type != DLT_EN10MB)
      Error_msg("%s : Interface not supported ( only DLT_EN10MB) | %d", iface, type);

#if defined(BIOCGHDRCMPLT) && defined(BIOCSHDRCMPLT)     // auto fill the source mac address now set OFF
    if (ioctl(fd, BIOCSHDRCMPLT, &spoof_eth_src) == -1)
      ERROR_MSG(" ioctl(BIOCSHDRCMPLT)");
#endif

   i = 1;
   if (ioctl(fd, BIOCIMMEDIATE, &i) < 0)                    // Set immediate mode so packets are processed as they arrive.
      ERROR_MSG(" ioctl(BIOCIMMEDIATE)");


   if (ioctl(fd, BIOCSETF, (caddr_t)&filter) < 0)           // Set filter program.
      ERROR_MSG(" ioctl(BIOCSETF)");


   bpf_in_use = fd;

   return fd;

}



int Inet_GetRawPacket(int sock, char *buffer, int MTU, short *type)
{
   int len = 0, pktlen = 0;
   u_char *buf, *bp, *ep;
   static char MyMAC[6]={0x65,0x74,0x74,0x65,0x72,0x63};

   if (SocketBuffer == -1)                   // only the first time
      SocketBuffer = Buffer_Create(1.0e5);   // 100 K buffer


   Buffer_Get(SocketBuffer, &pktlen, sizeof(u_int));
   len = Buffer_Get(SocketBuffer, buffer, pktlen );

   if (type != NULL)
   {
       if (!strncmp(MyMAC,"etterc",6))    // only the first time...
           Inet_GetIfaceInfo(Options.netiface, NULL, MyMAC, NULL, NULL);
       if (!memcmp(MyMAC,buffer,6))
           *type = 0; // PACKET_HOST
       else
           *type = 1; // !PACKET_HOST
   }

   if (len > 0) return len;                     // there was pending fata.

   buf = (char *)calloc(size, sizeof(char));    // size is global and set by BIOCGBLEN

   len = read(sock, buf, size);


#define bhp ((struct bpf_hdr *)bp)              // Loop through the packet(s)
         bp = buf;
         ep = bp + len;
         while (bp < ep) {
            u_int caplen, hdrlen;

            caplen = bhp->bh_caplen;
            hdrlen = bhp->bh_hdrlen;

//          //  bp + hdrlen is my packet
//          //  caplen is the length

            if (caplen > MTU + ETH_HEADER) caplen = MTU + ETH_HEADER;  // evil workaround for the 1518 size packet with FCS

            Buffer_Put(SocketBuffer, &caplen, sizeof(u_int) );
            Buffer_Put(SocketBuffer, bp + hdrlen, caplen );

            bp += BPF_WORDALIGN(hdrlen + caplen);
         }
#undef bhp

   Buffer_Get(SocketBuffer, &pktlen, sizeof(u_int));
   len = Buffer_Get(SocketBuffer, buffer, pktlen );

   if (type != NULL)
   {
       if (!memcmp(MyMAC,buffer,6))
           *type = 0; // PACKET_HOST
       else
           *type = 1; // !PACKET_HOST
   }

   free(buf);

   return len;

}



int Inet_SendRawPacket(int sock, char *buffer, int len)
{

   int sent;

   sent = write(sock, buffer, len);
   if (sent < len)
   {
      while (errno == ENOBUFS)
      {
         usleep(5000);
         sent = write(sock, buffer, len);
         if (sent == len) return (sent);
      }

      Error_msg("ec_inet_macosx:%d write() %d(%d) | ERRNO : %d | %s \n", __LINE__, len, sent, errno, strerror(errno));
   }

   return (sent);
}



int Inet_SetPromisc(char *iface)
{

   DEBUG_MSG("Inet_SetPromisc %s %d", iface, bpf_in_use);

   if ( ioctl(bpf_in_use, BIOCPROMISC, NULL) < 0 )
      ERROR_MSG("ioctl(BIOCPROMISC)");

   return 0;
}



void Inet_Restore_ifr(void)
{

   // this function is not needed !!
   // when a bpf is closed, the interface is restored

}



void Inet_DisableForwarding(void)
{

   int mib[4];      // for sysctl()
   int val = 0;     // for sysctl()   disable
   size_t len;

   mib[0] = CTL_NET;
   mib[1] = PF_INET;
   mib[2] = IPPROTO_IP;
   mib[3] = IPCTL_FORWARDING;

   len = sizeof(IpForward_status);

   if( (sysctl(mib, 4, &IpForward_status, &len, &val, sizeof(val))) == -1)
    ERROR_MSG("sysctl() | net.inet.ip.forwarding");

   DEBUG_MSG("Inet_DisableForwarding | net.inet.ip.forwarding = %d  old_value = %d\n", val, IpForward_status);

   atexit(Inet_RestoreForwarding);

}



void Inet_RestoreForwarding(void)
{

   int mib[4];      // for sysctl()

   mib[0] = CTL_NET;
   mib[1] = PF_INET;
   mib[2] = IPPROTO_IP;
   mib[3] = IPCTL_FORWARDING;

   if (strcmp(ECThread_getname(pthread_self()), PROGRAM)) return;

   if( (sysctl(mib, 4, NULL, NULL, &IpForward_status, sizeof(IpForward_status))) == -1)
      ERROR_MSG("sysctl()");

   DEBUG_MSG("Inet_RestoreForwarding | net.inet.ip.forwarding = %d\n", IpForward_status);


}


char *Inet_MacFromIP(unsigned long ip)
{
   int mib[6];
   size_t len;
   char *buf, *next, *end;
   struct rt_msghdr *rtm;
   struct sockaddr_inarp *sin;
   struct sockaddr_dl *sdl;
   static char ETH_BROADCAST[6] = {0xFF,0xFF,0xFF,0xFF,0xFF,0xFF};

   DEBUG_MSG("Inet_MacFromIP");

   mib[0] = CTL_NET;
   mib[1] = AF_ROUTE;
   mib[2] = 0;
   mib[3] = AF_INET;
   mib[4] = NET_RT_FLAGS;
   mib[5] = RTF_LLINFO;

   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)
   {
      free(buf);
      ERROR_MSG("sysctl()");
   }
   end = buf + len;

   for (next = buf ; next < end ; next += rtm->rtm_msglen)
   {
      rtm = (struct rt_msghdr *)next;
      sin = (struct sockaddr_inarp *)(rtm + 1);
      sdl = (struct sockaddr_dl *)(sin + 1);

      if (sin->sin_addr.s_addr == ip && sdl->sdl_alen)
      {
         free(buf);
         return LLADDR(sdl);
      }
      else     // not in cache... try to find it...
      {
      	struct recv_packet recvpck;
         char MyMAC[6];
         u_long MyIP;
         int MTU, sock;
         TIME_DECLARE;

         DEBUG_MSG("Inet_MacFromIP -- try to find it");

         sock = Inet_OpenRawSock(Options.netiface);

         Inet_GetIfaceInfo(Options.netiface, &MTU, MyMAC, &MyIP, NULL);

         if (ip == MyIP)
         {
            DEBUG_MSG("Inet_MacFromIP -- try to find me... ;)");
            memcpy(LLADDR(sdl), MyMAC, ETHER_ADDR_LEN);
            Inet_CloseRawSock(sock);
            return (char *) LLADDR(sdl);
         }

      	recvpck.buf = Inet_Forge_packet( MTU + ALIGN_ETH_TO_WORD );
      	recvpck.aligned = recvpck.buf + ALIGN_ETH_TO_WORD;

         Inet_Forge_ethernet( recvpck.aligned, MyMAC, ETH_BROADCAST, ETH_P_ARP );

         Inet_Forge_arp( recvpck.aligned + ETH_HEADER, ARPOP_REQUEST,
                         MyMAC, MyIP,
                         ARP_BROADCAST, ip );

         Inet_SendRawPacket(sock, buf, ETH_HEADER + ARP_HEADER);

			memset(recvpck.aligned, 0, MTU);

         fcntl(sock, F_SETFL, O_NONBLOCK);
         TIME_START;

         do
         {
            int len;
            short pkttype;
            ETH_header *ethpkt;
            ARP_header *arppkt;

            len = Inet_GetRawPacket(sock, recvpck.aligned, MTU, &pkttype);

            ethpkt = (ETH_header *)recvpck.aligned;
            arppkt = (ARP_header *)(recvpck.aligned + ETH_HEADER);

            TIME_FINISH;

            if (len > 0 && pkttype == PACKET_HOST && ethpkt->type == htons(ETH_P_ARP) && arppkt->opcode == htons(ARPOP_REPLY))
            {
               if ( *(unsigned long *)arppkt->source_ip == ip )
               {
                  memcpy(LLADDR(sdl), &arppkt->source_add, ETHER_ADDR_LEN);
                  free(buf);
                  Inet_Forge_packet_destroy( recvpck.buf );
                  Inet_CloseRawSock(sock);
                  return (char *) LLADDR(sdl);
               }
            }
         } while ( TIME_ELAPSED < 0.5 );
         Inet_Forge_packet_destroy( recvpck.buf );
         Inet_CloseRawSock(sock);
      }
   }
   free(buf);

   return ETH_BROADCAST;  // workaround for non local ip

}


/* EOF */

// vim:ts=3:expandtab