src/network/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 <fcntl.h>
  21 #include <linux/if_tun.h>
  22 #include <net/if.h>
  23 #include <netinet/if_ether.h>
  24 #include <sys/ioctl.h>
  25 #include <sys/stat.h>
  26 #include <sys/types.h>
  27
  28 #include "alloc-util.h"
  29 #include "fd-util.h"
  30 #include "netdev/tuntap.h"
  31 #include "user-util.h"
  32
  33 #define TUN_DEV "/dev/net/tun"
  34
  35 static int netdev_fill_tuntap_message(NetDev *netdev, struct ifreq *ifr) {
  36         TunTap *t;
  37
  38         assert(netdev);
  39         assert(netdev->ifname);
  40         assert(ifr);
  41
  42         if (netdev->kind == NETDEV_KIND_TAP) {
  43                 t = TAP(netdev);
  44                 ifr->ifr_flags |= IFF_TAP;
  45         } else {
  46                 t = TUN(netdev);
  47                 ifr->ifr_flags |= IFF_TUN;
  48         }
  49
  50         if (!t->packet_info)
  51                 ifr->ifr_flags |= IFF_NO_PI;
  52
  53         if (t->one_queue)
  54                 ifr->ifr_flags |= IFF_ONE_QUEUE;
  55
  56         if (t->multi_queue)
  57                 ifr->ifr_flags |= IFF_MULTI_QUEUE;
  58
  59         if (t->vnet_hdr)
  60                 ifr->ifr_flags |= IFF_VNET_HDR;
  61
  62         strncpy(ifr->ifr_name, netdev->ifname, IFNAMSIZ-1);
  63
  64         return 0;
  65 }
  66
  67 static int netdev_tuntap_add(NetDev *netdev, struct ifreq *ifr) {
  68         _cleanup_close_ int fd;
  69         TunTap *t = NULL;
  70         const char *user;
  71         const char *group;
  72         uid_t uid;
  73         gid_t gid;
  74         int r;
  75
  76         assert(netdev);
  77         assert(ifr);
  78
  79         fd = open(TUN_DEV, O_RDWR);
  80         if (fd < 0)
  81                 return log_netdev_error_errno(netdev, -errno,  "Failed to open tun dev: %m");
  82
  83         r = ioctl(fd, TUNSETIFF, ifr);
  84         if (r < 0)
  85                 return log_netdev_error_errno(netdev, -errno, "TUNSETIFF failed on tun dev: %m");
  86
  87         if (netdev->kind == NETDEV_KIND_TAP)
  88                 t = TAP(netdev);
  89         else
  90                 t = TUN(netdev);
  91
  92         assert(t);
  93
  94         if (t->user_name) {
  95
  96                 user = t->user_name;
  97
  98                 r = get_user_creds(&user, &uid, NULL, NULL, NULL);
  99                 if (r < 0)
 100                         return log_netdev_error_errno(netdev, r, "Cannot resolve user name %s: %m", t->user_name);
 101
 102                 r = ioctl(fd, TUNSETOWNER, uid);
 103                 if (r < 0)
 104                         return log_netdev_error_errno(netdev, -errno, "TUNSETOWNER failed on tun dev: %m");
 105         }
 106
 107         if (t->group_name) {
 108
 109                 group = t->group_name;
 110
 111                 r = get_group_creds(&group, &gid);
 112                 if (r < 0)
 113                         return log_netdev_error_errno(netdev, r, "Cannot resolve group name %s: %m", t->group_name);
 114
 115                 r = ioctl(fd, TUNSETGROUP, gid);
 116                 if (r < 0)
 117                         return log_netdev_error_errno(netdev, -errno, "TUNSETGROUP failed on tun dev: %m");
 118
 119         }
 120
 121         r = ioctl(fd, TUNSETPERSIST, 1);
 122         if (r < 0)
 123                 return log_netdev_error_errno(netdev, -errno, "TUNSETPERSIST failed on tun dev: %m");
 124
 125         return 0;
 126 }
 127
 128 static int netdev_create_tuntap(NetDev *netdev) {
 129         struct ifreq ifr = {};
 130         int r;
 131
 132         r = netdev_fill_tuntap_message(netdev, &ifr);
 133         if (r < 0)
 134                 return r;
 135
 136         return netdev_tuntap_add(netdev, &ifr);
 137 }
 138
 139 static void tuntap_done(NetDev *netdev) {
 140         TunTap *t = NULL;
 141
 142         assert(netdev);
 143
 144         if (netdev->kind == NETDEV_KIND_TUN)
 145                 t = TUN(netdev);
 146         else
 147                 t = TAP(netdev);
 148
 149         assert(t);
 150
 151         t->user_name = mfree(t->user_name);
 152         t->group_name = mfree(t->group_name);
 153 }
 154
 155 static int tuntap_verify(NetDev *netdev, const char *filename) {
 156         assert(netdev);
 157
 158         if (netdev->mtu)
 159                 log_netdev_warning(netdev, "MTU configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 160
 161         if (netdev->mac)
 162                 log_netdev_warning(netdev, "MAC configured for %s, ignoring", netdev_kind_to_string(netdev->kind));
 163
 164         return 0;
 165 }
 166
 167 const NetDevVTable tun_vtable = {
 168         .object_size = sizeof(TunTap),
 169         .sections = "Match\0NetDev\0Tun\0",
 170         .config_verify = tuntap_verify,
 171         .done = tuntap_done,
 172         .create = netdev_create_tuntap,
 173         .create_type = NETDEV_CREATE_INDEPENDENT,
 174 };
 175
 176 const NetDevVTable tap_vtable = {
 177         .object_size = sizeof(TunTap),
 178         .sections = "Match\0NetDev\0Tap\0",
 179         .config_verify = tuntap_verify,
 180         .done = tuntap_done,
 181         .create = netdev_create_tuntap,
 182         .create_type = NETDEV_CREATE_INDEPENDENT,
 183 };