vde-2/src/vde_tunctl.c

   1 /* Copyright 2002 Jeff Dike
   2  * Licensed under the GPL
   3  */
   4
   5 #include <stdio.h>
   6 #include <stdlib.h>
   7 #include <string.h>
   8 #include <errno.h>
   9 #include <fcntl.h>
  10 #include <unistd.h>
  11 #include <pwd.h>
  12 #include <grp.h>
  13 #include <net/if.h>
  14 #include <sys/ioctl.h>
  15 #include <linux/if_tun.h>
  16
  17 /* TUNSETGROUP appeared in 2.6.23 */
  18 #ifndef TUNSETGROUP
  19 #define TUNSETGROUP   _IOW('T', 206, int)
  20 #endif
  21
  22 static void Usage(char *name)
  23 {
  24   fprintf(stderr, "Create: %s [-b] [-u owner] [-g group] [-n] [-t device-name] "
  25           "[-f tun-clone-device]\n", name);
  26   fprintf(stderr, "Delete: %s -d device-name [-f tun-clone-device]\n\n",
  27           name);
  28   fprintf(stderr, "The default tun clone device is /dev/net/tun - some systems"
  29           " use\n/dev/misc/net/tun instead\n\n");
  30   fprintf(stderr, "-b will result in brief output (just the device name)\n");
  31   fprintf(stderr, "-n create a tun interface (not needed if the device name prefix is tun\n");
  32   exit(1);
  33 }
  34
  35 int main(int argc, char **argv)
  36 {
  37   struct ifreq ifr;
  38   struct passwd *pw;
  39         struct group *gr;
  40         uid_t owner = -1;
  41         gid_t group = -1;
  42   int tap_fd, opt, delete = 0, brief = 0;
  43         int type=IFF_TAP;
  44
  45   char *tun = "", *file = "/dev/net/tun", *name = argv[0], *end;
  46
  47   while((opt = getopt(argc, argv, "bd:f:t:u:in")) > 0){
  48     switch(opt) {
  49       case 'b':
  50         brief = 1;
  51         break;
  52       case 'd':
  53         delete = 1;
  54                                 tun = optarg;
  55         break;
  56       case 'f':
  57                                 file = optarg;
  58                                 break;
  59       case 'u':
  60                                 pw = getpwnam(optarg);
  61                                 if(pw != NULL){
  62                                         owner = pw->pw_uid;
  63                                         break;
  64                                 }
  65                                 owner = strtol(optarg, &end, 0);
  66                                 if(*end != '\0'){
  67                                         fprintf(stderr, "'%s' is neither a username nor a numeric uid.\n",
  68                                                         optarg);
  69                                         Usage(name);
  70                                 }
  71                                 break;
  72                         case 'g':
  73                                 gr = getgrnam(optarg);
  74                                 if(gr != NULL){
  75                                         group = gr->gr_gid;
  76                                         break;
  77                                 }
  78                                 group = strtol(optarg, &end, 0);
  79                                 if(*end != '\0'){
  80                                         fprintf(stderr, "'%s' is neither a groupname nor a numeric group.\n",
  81                                                         optarg);
  82                                         Usage(name);
  83                                 }
  84                                 break;
  85                         case 't':
  86         tun = optarg;
  87         break;
  88                         case 'n':
  89                                 type = IFF_TUN;
  90                                 break;
  91       case 'h':
  92       default:
  93         Usage(name);
  94     }
  95   }
  96
  97   argv += optind;
  98   argc -= optind;
  99
 100   if(argc > 0)
 101     Usage(name);
 102
 103   if((tap_fd = open(file, O_RDWR)) < 0){
 104     fprintf(stderr, "Failed to open '%s' : ", file);
 105     perror("");
 106     exit(1);
 107   }
 108
 109   memset(&ifr, 0, sizeof(ifr));
 110
 111         if (strncmp(tun,"tun",3)==0) type=IFF_TUN;
 112   ifr.ifr_flags = type | IFF_NO_PI;
 113   strncpy(ifr.ifr_name, tun, sizeof(ifr.ifr_name) - 1);
 114   if(ioctl(tap_fd, TUNSETIFF, (void *) &ifr) < 0){
 115     perror("TUNSETIFF");
 116     exit(1);
 117   }
 118
 119   if(delete){
 120     if(ioctl(tap_fd, TUNSETPERSIST, 0) < 0){
 121       perror("TUNSETPERSIST");
 122       exit(1);
 123     }
 124     printf("Set '%s' nonpersistent\n", ifr.ifr_name);
 125   }
 126   else {
 127                 /* emulate behaviour prior to TUNSETGROUP */
 128                 if(owner == -1 && group == -1) {
 129                         owner = geteuid();
 130                 }
 131
 132                 if(owner != -1) {
 133                         if(ioctl(tap_fd, TUNSETOWNER, owner) < 0){
 134                                 perror("TUNSETOWNER");
 135                                 exit(1);
 136                         }
 137                 }
 138                 if(group != -1) {
 139                         if(ioctl(tap_fd, TUNSETGROUP, group) < 0){
 140                                 perror("TUNSETGROUP");
 141                                 exit(1);
 142                         }
 143                 }
 144
 145     if(ioctl(tap_fd, TUNSETPERSIST, 1) < 0){
 146       perror("TUNSETPERSIST");
 147       exit(1);
 148     }
 149     if(brief)
 150       printf("%s\n", ifr.ifr_name);
 151                 else {
 152                         printf("Set '%s' persistent and owned by", ifr.ifr_name);
 153                         if(owner != -1)
 154                                 printf(" uid %d", owner);
 155                         if(group != -1)
 156                                 printf(" gid %d", group);
 157                         printf("\n");
 158                 }
 159         }
 160         return(0);
 161 }