141 lines
2.9 KiB
C
141 lines
2.9 KiB
C
/*modeled after tunctl by Jeff Dike */
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#include <arpa/inet.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <errno.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <pwd.h>
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#include <grp.h>
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#include <net/if.h>
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#include <sys/ioctl.h>
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#include <linux/if.h>
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#include <linux/if_tun.h>
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#ifndef TUNSETGROUP
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#define TUNSETGROUP _IOW('T', 206, int)
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#endif
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static void
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usage(char *name)
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{
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fprintf(stderr,
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"Create: %s [-b] [-u owner] [-g group] [-t device-name]\n",
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name);
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fprintf(stderr, "Delete: %s -d device-name\n", name);
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}
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int
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main(int argc, char **argv)
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{
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struct ifreq ifr;
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struct passwd *pw;
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struct group *gr;
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uid_t owner = -1;
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gid_t group = -1;
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int tun_fd, opt, delete = 0;
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const char *tun = "", *file = "/dev/net/tun";
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char *name = argv[0], *end;
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while ((opt = getopt(argc, argv, "bd:f:t:u:g:")) > 0) {
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switch (opt) {
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case 'd':
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delete = 1;
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tun = optarg;
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break;
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case 'u':
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pw = getpwnam(optarg);
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if (pw != NULL) {
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owner = pw->pw_uid;
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break;
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}
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owner = strtol(optarg, &end, 0);
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if (*end != '\0') {
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fprintf(stderr,
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"'%s' is neither a username nor a numeric uid.\n",
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optarg);
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usage(name);
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exit(EXIT_FAILURE);
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}
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break;
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case 'g':
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gr = getgrnam(optarg);
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if (gr != NULL) {
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group = gr->gr_gid;
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break;
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}
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group = strtol(optarg, &end, 0);
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if (*end != '\0') {
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fprintf(stderr,
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"'%s' is neither a groupname nor a numeric group.\n",
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optarg);
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usage(name);
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exit(EXIT_FAILURE);
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}
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break;
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case 't':
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tun = optarg;
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break;
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case 'h':
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default:
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usage(name);
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exit(EXIT_FAILURE);
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}
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}
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argv += optind;
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argc -= optind;
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if (argc > 0) {
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usage(name);
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exit(EXIT_FAILURE);
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}
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if ((tun_fd = open(file, O_RDWR)) < 0) {
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fprintf(stderr, "Failed to open '%s' : ", file);
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perror("");
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exit(1);
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}
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memset(&ifr, 0, sizeof (ifr));
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ifr.ifr_flags = IFF_TUN | TUN_NO_PI;
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strncpy(ifr.ifr_name, tun, sizeof (ifr.ifr_name) - 1);
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if (ioctl(tun_fd, TUNSETIFF, (void *) &ifr) < 0) {
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perror("TUNSETIFF");
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exit(1);
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}
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if (delete) {
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if (ioctl(tun_fd, TUNSETPERSIST, 0) < 0) {
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perror("disabling TUNSETPERSIST");
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exit(EXIT_FAILURE);
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}
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printf("Set '%s' nonpersistent\n", ifr.ifr_name);
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} else {
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/* emulate behaviour prior to TUNSETGROUP */
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if (owner == (uid_t) -1 && group == (gid_t) -1) {
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owner = geteuid();
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}
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if (owner != (uid_t) -1) {
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if (ioctl(tun_fd, TUNSETOWNER, owner) < 0) {
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perror("TUNSETOWNER");
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exit(EXIT_FAILURE);
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}
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}
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if (group != (gid_t) -1) {
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if (ioctl(tun_fd, TUNSETGROUP, group) < 0) {
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perror("TUNSETGROUP");
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exit(EXIT_FAILURE);
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}
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}
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if (ioctl(tun_fd, TUNSETPERSIST, 1) < 0) {
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perror("enabling TUNSETPERSIST");
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exit(EXIT_FAILURE);
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}
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printf("Set '%s' persistent and owned by", ifr.ifr_name);
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if (owner != (uid_t) -1)
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printf(" uid %d", owner);
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if (group != (gid_t) -1)
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printf(" gid %d", group);
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printf("\n");
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}
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exit(EXIT_SUCCESS);
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}
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