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/* 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.
*/
//config:config TUNCTL
//config: bool "tunctl (6.2 kb)"
//config: default y
//config: help
//config: tunctl creates or deletes tun devices.
//config:
//config:config FEATURE_TUNCTL_UG
//config: bool "Support owner:group assignment"
//config: default y
//config: depends on TUNCTL
//config: help
//config: Allow to specify owner and group of newly created interface.
//config: 340 bytes of pure bloat. Say no here.
//applet:IF_TUNCTL(APPLET_NOEXEC(tunctl, tunctl, BB_DIR_SBIN, BB_SUID_DROP, tunctl))
//kbuild:lib-$(CONFIG_TUNCTL) += tunctl.o
//usage:#define tunctl_trivial_usage
//usage: "[-f DEVICE] [-t NAME | -d NAME]" IF_FEATURE_TUNCTL_UG(" [-u USER] [-g GRP] [-b]")
//usage:#define tunctl_full_usage "\n\n"
//usage: "Create or delete TUN/TAP interfaces\n"
//usage: "\n -f DEV TUN device (default /dev/net/tun)"
//usage: "\n -t NAME Create iface (default: tapN)"
//usage: "\n -d NAME Delete iface"
//usage: IF_FEATURE_TUNCTL_UG(
//usage: "\n -u USER Set iface owner"
//usage: "\n -g GRP 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
};
opts = getopt32(argv, "^"
"f:t:d:" IF_FEATURE_TUNCTL_UG("u:g:b")
"\0"
"=0:t--d:d--t", // no arguments; t ^ d
&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);
printf("Set '%s' nonpersistent\n", ifr.ifr_name);
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
};
opts = getopt32(argv, "^"
"f:t:d:u:g:b" // u, g, b accepted and ignored
"\0"
"=0:t--d:d--t", // no arguments; t ^ d
&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
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