release/src/router/busybox/networking/tunctl.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * tun devices controller
   4  *
   5  * Copyright (C) 2008 by Vladimir Dronnikov <dronnikov@gmail.com>
   6  *
   7  * Original code:
   8  *      Jeff Dike
   9  *
  10  * Licensed under GPLv2, see file LICENSE in this tarball for details.
  11  */
  12 #include <netinet/in.h>
  13 #include <net/if.h>
  14 #include <linux/if_tun.h>
  15 #include "libbb.h"
  16
  17 /* TUNSETGROUP appeared in 2.6.23 */
  18 #ifndef TUNSETGROUP
  19 #define TUNSETGROUP _IOW('T', 206, int)
  20 #endif
  21
  22 #define IOCTL(a, b, c) ioctl_or_perror_and_die(a, b, c, NULL)
  23
  24 #if 1
  25
  26 int tunctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  27 int tunctl_main(int argc UNUSED_PARAM, char **argv)
  28 {
  29         struct ifreq ifr;
  30         int fd;
  31         const char *opt_name = "tap%d";
  32         const char *opt_device = "/dev/net/tun";
  33 #if ENABLE_FEATURE_TUNCTL_UG
  34         const char *opt_user, *opt_group;
  35         long user = -1, group = -1;
  36 #endif
  37         unsigned opts;
  38
  39         enum {
  40                 OPT_f = 1 << 0, // control device name (/dev/net/tun)
  41                 OPT_t = 1 << 1, // create named interface
  42                 OPT_d = 1 << 2, // delete named interface
  43 #if ENABLE_FEATURE_TUNCTL_UG
  44                 OPT_u = 1 << 3, // set new interface owner
  45                 OPT_g = 1 << 4, // set new interface group
  46                 OPT_b = 1 << 5, // brief output
  47 #endif
  48         };
  49
  50         opt_complementary = "=0:t--d:d--t"; // no arguments; t ^ d
  51         opts = getopt32(argv, "f:t:d:" USE_FEATURE_TUNCTL_UG("u:g:b"),
  52                         &opt_device, &opt_name, &opt_name
  53                         USE_FEATURE_TUNCTL_UG(, &opt_user, &opt_group));
  54
  55         // select device
  56         memset(&ifr, 0, sizeof(ifr));
  57         ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
  58         strncpy_IFNAMSIZ(ifr.ifr_name, opt_name);
  59
  60         // open device
  61         fd = xopen(opt_device, O_RDWR);
  62         IOCTL(fd, TUNSETIFF, (void *)&ifr);
  63
  64         // delete?
  65         if (opts & OPT_d) {
  66                 IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)0);
  67                 bb_info_msg("Set '%s' %spersistent", ifr.ifr_name, "non");
  68                 return EXIT_SUCCESS;
  69         }
  70
  71         // create
  72 #if ENABLE_FEATURE_TUNCTL_UG
  73         if (opts & OPT_g) {
  74                 group = xgroup2gid(opt_group);
  75                 IOCTL(fd, TUNSETGROUP, (void *)(uintptr_t)group);
  76         } else
  77                 user = geteuid();
  78         if (opts & OPT_u)
  79                 user = xuname2uid(opt_user);
  80         IOCTL(fd, TUNSETOWNER, (void *)(uintptr_t)user);
  81 #endif
  82         IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)1);
  83
  84         // show info
  85 #if ENABLE_FEATURE_TUNCTL_UG
  86         if (opts & OPT_b) {
  87                 puts(ifr.ifr_name);
  88         } else {
  89                 printf("Set '%s' %spersistent", ifr.ifr_name, "");
  90                 printf(" and owned by uid %ld", user);
  91                 if (group != -1)
  92                         printf(" gid %ld", group);
  93                 bb_putchar('\n');
  94         }
  95 #else
  96         puts(ifr.ifr_name);
  97 #endif
  98         return EXIT_SUCCESS;
  99 }
 100
 101 #else
 102
 103 /* -210 bytes: */
 104
 105 int tunctl_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
 106 int tunctl_main(int argc UNUSED_PARAM, char **argv)
 107 {
 108         struct ifreq ifr;
 109         int fd;
 110         const char *opt_name = "tap%d";
 111         const char *opt_device = "/dev/net/tun";
 112         unsigned opts;
 113
 114         enum {
 115                 OPT_f = 1 << 0, // control device name (/dev/net/tun)
 116                 OPT_t = 1 << 1, // create named interface
 117                 OPT_d = 1 << 2, // delete named interface
 118         };
 119
 120         opt_complementary = "=0:t--d:d--t"; // no arguments; t ^ d
 121         opts = getopt32(argv, "f:t:d:u:g:b", // u, g, b accepted and ignored
 122                         &opt_device, &opt_name, &opt_name, NULL, NULL);
 123
 124         // set interface name
 125         memset(&ifr, 0, sizeof(ifr));
 126         ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
 127         strncpy_IFNAMSIZ(ifr.ifr_name, opt_name);
 128
 129         // open device
 130         fd = xopen(opt_device, O_RDWR);
 131         IOCTL(fd, TUNSETIFF, (void *)&ifr);
 132
 133         // create or delete interface
 134         IOCTL(fd, TUNSETPERSIST, (void *)(uintptr_t)(0 == (opts & OPT_d)));
 135
 136         return EXIT_SUCCESS;
 137 }
 138
 139 #endif