Line data    Source code

       1             : /*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
       2             : 
       3             : /***
       4             :   This file is part of systemd.
       5             : 
       6             :   Copyright 2010 Lennart Poettering
       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 <stdlib.h>
      24             : 
      25             : #include "sd-netlink.h"
      26             : #include "netlink-util.h"
      27             : #include "missing.h"
      28             : #include "loopback-setup.h"
      29             : 
      30           0 : static int start_loopback(sd_netlink *rtnl) {
      31           0 :         _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL;
      32             :         int r;
      33             : 
      34           0 :         r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX);
      35           0 :         if (r < 0)
      36           0 :                 return r;
      37             : 
      38           0 :         r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP);
      39           0 :         if (r < 0)
      40           0 :                 return r;
      41             : 
      42           0 :         r = sd_netlink_call(rtnl, req, 0, NULL);
      43           0 :         if (r < 0)
      44           0 :                 return r;
      45             : 
      46           0 :         return 0;
      47             : }
      48             : 
      49           0 : static bool check_loopback(sd_netlink *rtnl) {
      50           0 :         _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL;
      51             :         unsigned flags;
      52             :         int r;
      53             : 
      54           0 :         r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX);
      55           0 :         if (r < 0)
      56           0 :                 return false;
      57             : 
      58           0 :         r = sd_netlink_call(rtnl, req, 0, &reply);
      59           0 :         if (r < 0)
      60           0 :                 return false;
      61             : 
      62           0 :         r = sd_rtnl_message_link_get_flags(reply, &flags);
      63           0 :         if (r < 0)
      64           0 :                 return false;
      65             : 
      66           0 :         return flags & IFF_UP;
      67             : }
      68             : 
      69           0 : int loopback_setup(void) {
      70           0 :         _cleanup_netlink_unref_ sd_netlink *rtnl = NULL;
      71             :         int r;
      72             : 
      73           0 :         r = sd_netlink_open(&rtnl);
      74           0 :         if (r < 0)
      75           0 :                 return r;
      76             : 
      77           0 :         r = start_loopback(rtnl);
      78           0 :         if (r < 0) {
      79             : 
      80             :                 /* If we lack the permissions to configure the
      81             :                  * loopback device, but we find it to be already
      82             :                  * configured, let's exit cleanly, in order to
      83             :                  * supported unprivileged containers. */
      84           0 :                 if (r == -EPERM && check_loopback(rtnl))
      85           0 :                         return 0;
      86             : 
      87           0 :                 return log_warning_errno(r, "Failed to configure loopback device: %m");
      88             :         }
      89             : 
      90           0 :         return 0;
      91             : }