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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, int status)
- {
- 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(status);
- }
- 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:h")) > 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, 1);
- }
- 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, 1);
- }
- break;
- case 't':
- tun = optarg;
- break;
- case 'h':
- Usage(name, 0);
- break;
- default:
- Usage(name, 1);
- }
- }
- argv += optind;
- argc -= optind;
- if(argc > 0)
- Usage(name, 1);
- 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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