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