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/* Copyright 2002 Jeff Dike
* Licensed under the GPL
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <pwd.h>
#include <grp.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <linux/if_tun.h>
/* TUNSETGROUP appeared in 2.6.23 */
#ifndef TUNSETGROUP
#define TUNSETGROUP _IOW('T', 206, int)
#endif
static void Usage(char *name)
{
fprintf(stderr, "Create: %s [-b] [-u owner] [-g group] [-t device-name] "
"[-f tun-clone-device]\n", name);
fprintf(stderr, "Delete: %s -d device-name [-f tun-clone-device]\n\n",
name);
fprintf(stderr, "The default tun clone device is /dev/net/tun - some systems"
" use\n/dev/misc/net/tun instead\n\n");
fprintf(stderr, "-b will result in brief output (just the device name)\n");
exit(1);
}
int main(int argc, char **argv)
{
struct ifreq ifr;
struct passwd *pw;
struct group *gr;
uid_t owner = -1;
gid_t group = -1;
int tap_fd, opt, delete = 0, brief = 0;
char *tun = "", *file = "/dev/net/tun", *name = argv[0], *end;
while((opt = getopt(argc, argv, "bd:f:t:u:g:")) > 0){
switch(opt) {
case 'b':
brief = 1;
break;
case 'd':
delete = 1;
tun = optarg;
break;
case 'f':
file = optarg;
break;
case 'u':
pw = getpwnam(optarg);
if(pw != NULL){
owner = pw->pw_uid;
break;
}
owner = strtol(optarg, &end, 0);
if(*end != '\0'){
fprintf(stderr, "'%s' is neither a username nor a numeric uid.\n",
optarg);
Usage(name);
}
break;
case 'g':
gr = getgrnam(optarg);
if(gr != NULL){
group = gr->gr_gid;
break;
}
group = strtol(optarg, &end, 0);
if(*end != '\0'){
fprintf(stderr, "'%s' is neither a groupname nor a numeric group.\n",
optarg);
Usage(name);
}
break;
case 't':
tun = optarg;
break;
case 'h':
default:
Usage(name);
}
}
argv += optind;
argc -= optind;
if(argc > 0)
Usage(name);
if((tap_fd = open(file, O_RDWR)) < 0){
fprintf(stderr, "Failed to open '%s' : ", file);
perror("");
exit(1);
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, tun, sizeof(ifr.ifr_name) - 1);
if(ioctl(tap_fd, TUNSETIFF, (void *) &ifr) < 0){
perror("TUNSETIFF");
exit(1);
}
if(delete){
if(ioctl(tap_fd, TUNSETPERSIST, 0) < 0){
perror("disabling TUNSETPERSIST");
exit(1);
}
printf("Set '%s' nonpersistent\n", ifr.ifr_name);
}
else {
/* emulate behaviour prior to TUNSETGROUP */
if(owner == -1 && group == -1) {
owner = geteuid();
}
if(owner != -1) {
if(ioctl(tap_fd, TUNSETOWNER, owner) < 0){
perror("TUNSETOWNER");
exit(1);
}
}
if(group != -1) {
if(ioctl(tap_fd, TUNSETGROUP, group) < 0){
perror("TUNSETGROUP");
exit(1);
}
}
if(ioctl(tap_fd, TUNSETPERSIST, 1) < 0){
perror("enabling TUNSETPERSIST");
exit(1);
}
if(brief)
printf("%s\n", ifr.ifr_name);
else {
printf("Set '%s' persistent and owned by", ifr.ifr_name);
if(owner != -1)
printf(" uid %d", owner);
if(group != -1)
printf(" gid %d", group);
printf("\n");
}
}
return(0);
}
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