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 #include <netinet/if_ether.h>
  24
  25 #include "alloc-util.h"
  26 #include "fd-util.h"
  27 #include "networkd-netdev-tuntap.h"
  28 #include "user-util.h"
  29
  30 #define TUN_DEV "/dev/net/tun"
  31
  32 static int netdev_fill_tuntap_message(NetDev *netdev, struct ifreq *ifr) {
  33         TunTap *t;
  34
  35         assert(netdev);
  36         assert(netdev->ifname);
  37         assert(ifr);
  38
  39         if (netdev->kind == NETDEV_KIND_TAP) {
  40                 t = TAP(netdev);
  41                 ifr->ifr_flags |= IFF_TAP;
  42         } else {
  43                 t = TUN(netdev);
  44                 ifr->ifr_flags |= IFF_TUN;
  45         }
  46
  47         if (!t->packet_info)
  48                 ifr->ifr_flags |= IFF_NO_PI;
  49
  50         if (t->one_queue)
  51                 ifr->ifr_flags |= IFF_ONE_QUEUE;
  52
  53         if (t->multi_queue)
  54                 ifr->ifr_flags |= IFF_MULTI_QUEUE;
  55
  56         if (t->vnet_hdr)
  57                 ifr->ifr_flags |= IFF_VNET_HDR;
  58
  59         strncpy(ifr->ifr_name, netdev->ifname, IFNAMSIZ-1);
  60
  61         return 0;
  62 }
  63
  64 static int netdev_tuntap_add(NetDev *netdev, struct ifreq *ifr) {
  65         _cleanup_close_ int fd;
  66         TunTap *t = NULL;
  67         const char *user;
  68         const char *group;
  69         uid_t uid;
  70         gid_t gid;
  71         int r;
  72
  73         assert(netdev);
  74         assert(ifr);
  75
  76         fd = open(TUN_DEV, O_RDWR);
  77         if (fd < 0)
  78                 return log_netdev_error_errno(netdev, -errno,  "Failed to open tun dev: %m");
  79
  80         r = ioctl(fd, TUNSETIFF, ifr);
  81         if (r < 0)
  82                 return log_netdev_error_errno(netdev, -errno, "TUNSETIFF failed on tun dev: %m");
  83
  84         if (netdev->kind == NETDEV_KIND_TAP)
  85                 t = TAP(netdev);
  86         else
  87                 t = TUN(netdev);
  88
  89         assert(t);
  90
  91         if (t->user_name) {
  92
  93                 user = t->user_name;
  94
  95                 r = get_user_creds(&user, &uid, NULL, NULL, NULL);
  96                 if (r < 0)
  97                         return log_netdev_error_errno(netdev, r, "Cannot resolve user name %s: %m", t->user_name);
  98
  99                 r = ioctl(fd, TUNSETOWNER, uid);
 100                 if (r < 0)
 101                         return log_netdev_error_errno(netdev, -errno, "TUNSETOWNER failed on tun dev: %m");
 102         }
 103
 104         if (t->group_name) {
 105
 106                 group = t->group_name;
 107
 108                 r = get_group_creds(&group, &gid);
 109                 if (r < 0)
 110                         return log_netdev_error_errno(netdev, r, "Cannot resolve group name %s: %m", t->group_name);
 111
 112                 r = ioctl(fd, TUNSETGROUP, gid);
 113                 if (r < 0)
 114                         return log_netdev_error_errno(netdev, -errno, "TUNSETGROUP failed on tun dev: %m");
 115
 116         }
 117
 118         r = ioctl(fd, TUNSETPERSIST, 1);
 119         if (r < 0)
 120                 return log_netdev_error_errno(netdev, -errno, "TUNSETPERSIST failed on tun dev: %m");
 121
 122         return 0;
 123 }
 124
 125 static int netdev_create_tuntap(NetDev *netdev) {
 126         struct ifreq ifr = {};
 127         int r;
 128
 129         r = netdev_fill_tuntap_message(netdev, &ifr);
 130         if (r < 0)
 131                 return r;
 132
 133         return netdev_tuntap_add(netdev, &ifr);
 134 }
 135
 136 static void tuntap_done(NetDev *netdev) {
 137         TunTap *t = NULL;
 138
 139         assert(netdev);
 140
 141         if (netdev->kind == NETDEV_KIND_TUN)
 142                 t = TUN(netdev);
 143         else
 144                 t = TAP(netdev);
 145
 146         assert(t);
 147
 148         t->user_name = mfree(t->user_name);
 149         t->group_name = mfree(t->group_name);
 150 }
 151
 152 static int tuntap_verify(NetDev *netdev, const char *filename) {
 153         assert(netdev);
 154
 155         if (netdev->mtu)
 156                 log_netdev_warning(netdev, "MTU configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 157
 158         if (netdev->mac)
 159                 log_netdev_warning(netdev, "MAC configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 160
 161         return 0;
 162 }
 163
 164 const NetDevVTable tun_vtable = {
 165         .object_size = sizeof(TunTap),
 166         .sections = "Match\0NetDev\0Tun\0",
 167         .config_verify = tuntap_verify,
 168         .done = tuntap_done,
 169         .create = netdev_create_tuntap,
 170         .create_type = NETDEV_CREATE_INDEPENDENT,
 171 };
 172
 173 const NetDevVTable tap_vtable = {
 174         .object_size = sizeof(TunTap),
 175         .sections = "Match\0NetDev\0Tap\0",
 176         .config_verify = tuntap_verify,
 177         .done = tuntap_done,
 178         .create = netdev_create_tuntap,
 179         .create_type = NETDEV_CREATE_INDEPENDENT,
 180 };