src/network/networkd-netdev-tuntap.c

   1 /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
   2
   3 /***
   4     This file is part of systemd.
   5
   6     Copyright 2014 Susant Sahani <susant@redhat.com>
   7
   8     systemd is free software; you can redistribute it and/or modify it
   9     under the terms of the GNU Lesser General Public License as published by
  10     the Free Software Foundation; either version 2.1 of the License, or
  11     (at your option) any later version.
  12
  13     systemd is distributed in the hope that it will be useful, but
  14     WITHOUT ANY WARRANTY; without even the implied warranty of
  15     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  16     Lesser General Public License for more details.
  17
  18     You should have received a copy of the GNU Lesser General Public License
  19     along with systemd; If not, see <http://www.gnu.org/licenses/>.
  20 ***/
  21
  22 #include <sys/ioctl.h>
  23 #include <net/if.h>
  24 #include <linux/if_tun.h>
  25
  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 };