1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

     2 /*

     3  * Copyright (c) University of Washington

     4  *

     5  * This program is free software; you can redistribute it and/or modify

     6  * it under the terms of the GNU General Public License version 2 as

     7  * published by the Free Software Foundation;

     8  *

     9  * This program is distributed in the hope that it will be useful,

    10  * but WITHOUT ANY WARRANTY; without even the implied warranty of

    11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

    12  * GNU General Public License for more details.

    13  *

    14  * You should have received a copy of the GNU General Public License

    15  * along with this program; if not, write to the Free Software

    16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    17  */

    18 

    19 #include <unistd.h>

    20 #include <string>

    21 #include <iostream>

    22 #include <iomanip>

    23 #include <sstream>

    24 #include <stdlib.h>

    25 #include <errno.h>

    26 

    27 #include <sys/socket.h>

    28 #include <sys/un.h>

    29 #include <sys/ioctl.h>

    30 #include <net/ethernet.h>

    31 #include <net/if.h>

    32 #include <netinet/in.h>

    33 #include <netpacket/packet.h>

    34 #include <arpa/inet.h>

    35 

    36 #include "creator-utils.h"

    37 

    38 #define EMU_MAGIC 65867

    39 

    40 using namespace ns3;

    41 

    42 int

    43 main (int argc, char *argv[])

    44 {

    45   int c;

    46   char *path = NULL;

    47 

    48   opterr = 0;

    49 

    50   while ((c = getopt (argc, argv, "vp:")) != -1)

    51     {

    52       switch (c)

    53         {

    54         case 'v':

    55           gVerbose = true;

    56           break;

    57         case 'p':

    58           path = optarg;

    59           break;

    60         }

    61     }

    62 

    63   //

    64   // This program is spawned by an emu net device running in a simulation.  It

    65   // wants to create a raw socket as described below.  We are going to do the

    66   // work here since we're running suid root.  Once we create the raw socket,

    67   // we have to send it back to the emu net device.  We do that over a Unix

    68   // (local interprocess) socket.  The emu net device created a socket to

    69   // listen for our response on, and it is expected to have encoded the address

    70   // information as a string and to have passed that string as an argument to

    71   // us.  We see it here as the "path" string.  We can't do anything useful

    72   // unless we have that string.

    73   //

    74   ABORT_IF (path == NULL, "path is a required argument", 0);

    75   LOG ("Provided path is \"" << path << "\"");

    76   //

    77   // The whole reason for all of the hoops we went through to call out to this

    78   // program will pay off here.  We created this program to run as suid root

    79   // in order to keep the main simulation program from having to be run with

    80   // root privileges.  We need root privileges to be able to open a raw socket

    81   // though.  So all of these hoops are to allow us to execute the following

    82   // single line of code:

    83   //

    84   LOG ("Creating raw socket");

    85   int sock = socket (PF_PACKET, SOCK_RAW, htons (ETH_P_ALL));

    86   ABORT_IF (sock == -1, "CreateSocket(): Unable to open raw socket", 1);

    87 

    88   //

    89   // Send the socket back to the emu net device so it can go about its business

    90   //

    91   SendSocket (path, sock, EMU_MAGIC);

    92 

    93   return 0;

    94 }

    95