etc/Mac/utun/17-15-utun.c

   1 #include <sys/types.h>
   2 #include <sys/ioctl.h>
   3 #include <sys/socket.h>
   4 #include <sys/sys_domain.h>
   5 #include <sys/kern_control.h>
   6 #include <net/if_utun.h>
   7 #include <errno.h>
   8 #include <stdio.h>
   9 #include <string.h>
  10 #include <syslog.h>
  11 #include <unistd.h>
  12
  13 #include <stdlib.h> // exit, etc.
  14
  15
  16 // Simple User-Tunneling Proof of Concept - extends listing 17-15 in book
  17 //
  18 // Compiles for both iOS and OS X..
  19 //
  20 // Coded by Jonathan Levin. Go ahead; Copy, improve - all rights allowed.
  21 //
  22 //  (though credit where credit is due would be nice ;-)
  23 // http://www.newosxbook.com/src.jl?tree=listings&file=17-15-utun.c     http://www.newosxbook.com/index.php?page=code
  24
  25 int
  26 tun(void)
  27 {
  28         struct sockaddr_ctl sc;
  29         struct ctl_info ctlInfo;
  30         int fd;
  31
  32
  33         memset(&ctlInfo, 0, sizeof(ctlInfo));
  34         if (strlcpy(ctlInfo.ctl_name, UTUN_CONTROL_NAME, sizeof(ctlInfo.ctl_name)) >=
  35             sizeof(ctlInfo.ctl_name)) {
  36                 fprintf(stderr,"UTUN_CONTROL_NAME too long");
  37                 return -1;
  38         }
  39         fd = socket(PF_SYSTEM, SOCK_DGRAM, SYSPROTO_CONTROL);
  40
  41         if (fd == -1) {
  42                 perror ("socket(SYSPROTO_CONTROL)");
  43                 return -1;
  44         }
  45         if (ioctl(fd, CTLIOCGINFO, &ctlInfo) == -1) {
  46                 perror ("ioctl(CTLIOCGINFO)");
  47                 close(fd);
  48                 return -1;
  49         }
  50
  51         sc.sc_id = ctlInfo.ctl_id;
  52         sc.sc_len = sizeof(sc);
  53         sc.sc_family = AF_SYSTEM;
  54         sc.ss_sysaddr = AF_SYS_CONTROL;
  55         sc.sc_unit = 2; /* Only have one, in this example... */
  56
  57
  58         // If the connect is successful, a tun%d device will be created, where "%d"
  59         // is our unit number -1
  60
  61         if (connect(fd, (struct sockaddr *)&sc, sizeof(sc)) == -1) {
  62                 perror ("connect(AF_SYS_CONTROL)");
  63                 close(fd);
  64                 return -1;
  65         }
  66         return fd;
  67 }
  68
  69 int
  70 main (int argc, char **argv)
  71 {
  72   int utunfd = tun();
  73
  74   if (utunfd == -1)
  75         {
  76                 fprintf(stderr,"Unable to establish UTUN descriptor - aborting\n");
  77                 exit(1);
  78         }
  79
  80   fprintf(stderr,"Utun interface is up.. Configure IPv4 using \"ifconfig utun1 _ipA_ _ipB_\"\n");
  81   fprintf(stderr,"                       Configure IPv6 using \"ifconfig utun1 inet6 _ip6_\"\n");
  82   fprintf(stderr,"Then (e.g.) ping _ipB_ (IPv6 will automatically generate ND messages)\n");
  83
  84
  85   // PoC - Just dump the packets...
  86   for (;;)
  87         {
  88                 unsigned char   c[1500];
  89                 int     len;
  90                 int     i;
  91
  92
  93                 len = read (utunfd,c, 1500);
  94
  95                 // First 4 bytes of read data are the AF: 2 for AF_INET, 1E for AF_INET6, etc..
  96                 for (i = 4; i< len; i++)
  97                 {
  98                    printf ("%02x ", c[i]);
  99                    if ( (i-4)%16 ==15) printf("\n");
 100                 }
 101                 printf ("\n");
 102
 103
 104         }
 105
 106    return(0);
 107 }