src/network/networkd-netdev-tuntap.c

   1 /***
   2     This file is part of systemd.
   3
   4     Copyright 2014 Susant Sahani <susant@redhat.com>
   5
   6     systemd is free software; you can redistribute it and/or modify it
   7     under the terms of the GNU Lesser General Public License as published by
   8     the Free Software Foundation; either version 2.1 of the License, or
   9     (at your option) any later version.
  10
  11     systemd is distributed in the hope that it will be useful, but
  12     WITHOUT ANY WARRANTY; without even the implied warranty of
  13     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  14     Lesser General Public License for more details.
  15
  16     You should have received a copy of the GNU Lesser General Public License
  17     along with systemd; If not, see <http://www.gnu.org/licenses/>.
  18 ***/
  19
  20 #include <net/if.h>
  21 #include <sys/ioctl.h>
  22 #include <linux/if_tun.h>
  23
  24 #include "alloc-util.h"
  25 #include "fd-util.h"
  26 #include "networkd-netdev-tuntap.h"
  27 #include "user-util.h"
  28
  29 #define TUN_DEV "/dev/net/tun"
  30
  31 static int netdev_fill_tuntap_message(NetDev *netdev, struct ifreq *ifr) {
  32         TunTap *t;
  33
  34         assert(netdev);
  35         assert(netdev->ifname);
  36         assert(ifr);
  37
  38         if (netdev->kind == NETDEV_KIND_TAP) {
  39                 t = TAP(netdev);
  40                 ifr->ifr_flags |= IFF_TAP;
  41         } else {
  42                 t = TUN(netdev);
  43                 ifr->ifr_flags |= IFF_TUN;
  44         }
  45
  46         if (!t->packet_info)
  47                 ifr->ifr_flags |= IFF_NO_PI;
  48
  49         if (t->one_queue)
  50                 ifr->ifr_flags |= IFF_ONE_QUEUE;
  51
  52         if (t->multi_queue)
  53                 ifr->ifr_flags |= IFF_MULTI_QUEUE;
  54
  55         if (t->vnet_hdr)
  56                 ifr->ifr_flags |= IFF_VNET_HDR;
  57
  58         strncpy(ifr->ifr_name, netdev->ifname, IFNAMSIZ-1);
  59
  60         return 0;
  61 }
  62
  63 static int netdev_tuntap_add(NetDev *netdev, struct ifreq *ifr) {
  64         _cleanup_close_ int fd;
  65         TunTap *t = NULL;
  66         const char *user;
  67         const char *group;
  68         uid_t uid;
  69         gid_t gid;
  70         int r;
  71
  72         assert(netdev);
  73         assert(ifr);
  74
  75         fd = open(TUN_DEV, O_RDWR);
  76         if (fd < 0)
  77                 return log_netdev_error_errno(netdev, -errno,  "Failed to open tun dev: %m");
  78
  79         r = ioctl(fd, TUNSETIFF, ifr);
  80         if (r < 0)
  81                 return log_netdev_error_errno(netdev, -errno, "TUNSETIFF failed on tun dev: %m");
  82
  83         if (netdev->kind == NETDEV_KIND_TAP)
  84                 t = TAP(netdev);
  85         else
  86                 t = TUN(netdev);
  87
  88         assert(t);
  89
  90         if(t->user_name) {
  91
  92                 user = t->user_name;
  93
  94                 r = get_user_creds(&user, &uid, NULL, NULL, NULL);
  95                 if (r < 0)
  96                         return log_netdev_error_errno(netdev, r, "Cannot resolve user name %s: %m", t->user_name);
  97
  98                 r = ioctl(fd, TUNSETOWNER, uid);
  99                 if (r < 0)
 100                         return log_netdev_error_errno(netdev, -errno, "TUNSETOWNER failed on tun dev: %m");
 101         }
 102
 103         if (t->group_name) {
 104
 105                 group = t->group_name;
 106
 107                 r = get_group_creds(&group, &gid);
 108                 if (r < 0)
 109                         return log_netdev_error_errno(netdev, r, "Cannot resolve group name %s: %m", t->group_name);
 110
 111                 r = ioctl(fd, TUNSETGROUP, gid);
 112                 if (r < 0)
 113                         return log_netdev_error_errno(netdev, -errno, "TUNSETGROUP failed on tun dev: %m");
 114
 115         }
 116
 117         r = ioctl(fd, TUNSETPERSIST, 1);
 118         if (r < 0)
 119                 return log_netdev_error_errno(netdev, -errno, "TUNSETPERSIST failed on tun dev: %m");
 120
 121         return 0;
 122 }
 123
 124 static int netdev_create_tuntap(NetDev *netdev) {
 125         struct ifreq ifr = {};
 126         int r;
 127
 128         r = netdev_fill_tuntap_message(netdev, &ifr);
 129         if(r < 0)
 130                 return r;
 131
 132         return netdev_tuntap_add(netdev, &ifr);
 133 }
 134
 135 static void tuntap_done(NetDev *netdev) {
 136         TunTap *t = NULL;
 137
 138         assert(netdev);
 139
 140         if (netdev->kind == NETDEV_KIND_TUN)
 141                 t = TUN(netdev);
 142         else
 143                 t = TAP(netdev);
 144
 145         assert(t);
 146
 147         t->user_name = mfree(t->user_name);
 148         t->group_name = mfree(t->group_name);
 149 }
 150
 151 static int tuntap_verify(NetDev *netdev, const char *filename) {
 152         assert(netdev);
 153
 154         if (netdev->mtu)
 155                 log_netdev_warning(netdev, "MTU configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 156
 157         if (netdev->mac)
 158                 log_netdev_warning(netdev, "MAC configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 159
 160         return 0;
 161 }
 162
 163 const NetDevVTable tun_vtable = {
 164         .object_size = sizeof(TunTap),
 165         .sections = "Match\0NetDev\0Tun\0",
 166         .config_verify = tuntap_verify,
 167         .done = tuntap_done,
 168         .create = netdev_create_tuntap,
 169         .create_type = NETDEV_CREATE_INDEPENDENT,
 170 };
 171
 172 const NetDevVTable tap_vtable = {
 173         .object_size = sizeof(TunTap),
 174         .sections = "Match\0NetDev\0Tap\0",
 175         .config_verify = tuntap_verify,
 176         .done = tuntap_done,
 177         .create = netdev_create_tuntap,
 178         .create_type = NETDEV_CREATE_INDEPENDENT,
 179 };