source: MondoRescue/branches/3.2/mindi-busybox/networking/tunctl.c@ 3232

/* vi: set sw=4 ts=4: */
/*
 * tun devices controller
 *
 * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
 *
 * Original code:
 *      Jeff Dike
 *
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */

//usage:#define tunctl_trivial_usage
//usage:       "[-f device] ([-t name] | -d name)" IF_FEATURE_TUNCTL_UG(" [-u owner] [-g group] [-b]")
//usage:#define tunctl_full_usage "\n\n"
//usage:       "Create or delete tun interfaces\n"
//usage:     "\n    -f name     tun device (/dev/net/tun)"
//usage:     "\n    -t name     Create iface 'name'"
//usage:     "\n    -d name     Delete iface 'name'"
//usage:    IF_FEATURE_TUNCTL_UG(
//usage:     "\n    -u owner    Set iface owner"
//usage:     "\n    -g group    Set iface group"
//usage:     "\n    -b      Brief output"
//usage:    )
//usage:
//usage:#define tunctl_example_usage
//usage:       "# tunctl\n"
//usage:       "# tunctl -d tun0\n"

#include <netinet/in.h>
#include <net/if.h>
#include <linux/if_tun.h>
#include "libbb.h"

/* TUNSETGROUP appeared in 2.6.23 */
#ifndef TUNSETGROUP
#define TUNSETGROUP _IOW('T', 206, int)
#endif

#define IOCTL(a, b, c) ioctl_or_perror_and_die(a, b, c, NULL)

#if 1

int tunctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tunctl_main(int argc UNUSED_PARAM, char **argv)
{
    struct ifreq ifr;
    int fd;
    const char *opt_name = "tap%d";
    const char *opt_device = "/dev/net/tun";
#if ENABLE_FEATURE_TUNCTL_UG
    const char *opt_user, *opt_group;
    long user = -1, group = -1;
#endif
    unsigned opts;

    enum {
        OPT_f = 1 << 0, // control device name (/dev/net/tun)
        OPT_t = 1 << 1, // create named interface
        OPT_d = 1 << 2, // delete named interface
#if ENABLE_FEATURE_TUNCTL_UG
        OPT_u = 1 << 3, // set new interface owner
        OPT_g = 1 << 4, // set new interface group
        OPT_b = 1 << 5, // brief output
#endif
    };

    opt_complementary = "=0:t--d:d--t"; // no arguments; t ^ d
    opts = getopt32(argv, "f:t:d:" IF_FEATURE_TUNCTL_UG("u:g:b"),
            &opt_device, &opt_name, &opt_name
            IF_FEATURE_TUNCTL_UG(, &opt_user, &opt_group));

    // select device
    memset(&ifr, 0, sizeof(ifr));
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    strncpy_IFNAMSIZ(ifr.ifr_name, opt_name);

    // open device
    fd = xopen(opt_device, O_RDWR);
    IOCTL(fd, TUNSETIFF, (void *)&ifr);

    // delete?
    if (opts & OPT_d) {
        IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)0);
        bb_info_msg("Set '%s' %spersistent", ifr.ifr_name, "non");
        return EXIT_SUCCESS;
    }

    // create
#if ENABLE_FEATURE_TUNCTL_UG
    if (opts & OPT_g) {
        group = xgroup2gid(opt_group);
        IOCTL(fd, TUNSETGROUP, (void *)(uintptr_t)group);
    } else
        user = geteuid();
    if (opts & OPT_u)
        user = xuname2uid(opt_user);
    IOCTL(fd, TUNSETOWNER, (void *)(uintptr_t)user);
#endif
    IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)1);

    // show info
#if ENABLE_FEATURE_TUNCTL_UG
    if (opts & OPT_b) {
        puts(ifr.ifr_name);
    } else {
        printf("Set '%s' %spersistent", ifr.ifr_name, "");
        printf(" and owned by uid %ld", user);
        if (group != -1)
            printf(" gid %ld", group);
        bb_putchar('\n');
    }
#else
    puts(ifr.ifr_name);
#endif
    return EXIT_SUCCESS;
}

#else

/* -210 bytes: */

int tunctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int tunctl_main(int argc UNUSED_PARAM, char **argv)
{
    struct ifreq ifr;
    int fd;
    const char *opt_name = "tap%d";
    const char *opt_device = "/dev/net/tun";
    unsigned opts;

    enum {
        OPT_f = 1 << 0, // control device name (/dev/net/tun)
        OPT_t = 1 << 1, // create named interface
        OPT_d = 1 << 2, // delete named interface
    };

    opt_complementary = "=0:t--d:d--t"; // no arguments; t ^ d
    opts = getopt32(argv, "f:t:d:u:g:b", // u, g, b accepted and ignored
            &opt_device, &opt_name, &opt_name, NULL, NULL);

    // set interface name
    memset(&ifr, 0, sizeof(ifr));
    ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
    strncpy_IFNAMSIZ(ifr.ifr_name, opt_name);

    // open device
    fd = xopen(opt_device, O_RDWR);
    IOCTL(fd, TUNSETIFF, (void *)&ifr);

    // create or delete interface
    IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)(0 == (opts & OPT_d)));

    return EXIT_SUCCESS;
}

#endif