/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ /*** This file is part of systemd. Copyright 2010 Lennart Poettering systemd is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser General Public License as published by the Free Software Foundation; either version 2.1 of the License, or (at your option) any later version. systemd is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details. You should have received a copy of the GNU Lesser General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <net/if.h> #include <stdlib.h> #include "sd-netlink.h" #include "netlink-util.h" #include "missing.h" #include "loopback-setup.h" static int start_loopback(sd_netlink *rtnl) { _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL; int r; r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX); if (r < 0) return r; r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP); if (r < 0) return r; r = sd_netlink_call(rtnl, req, 0, NULL); if (r < 0) return r; return 0; } static bool check_loopback(sd_netlink *rtnl) { _cleanup_netlink_message_unref_ sd_netlink_message *req = NULL, *reply = NULL; unsigned flags; int r; r = sd_rtnl_message_new_link(rtnl, &req, RTM_GETLINK, LOOPBACK_IFINDEX); if (r < 0) return false; r = sd_netlink_call(rtnl, req, 0, &reply); if (r < 0) return false; r = sd_rtnl_message_link_get_flags(reply, &flags); if (r < 0) return false; return flags & IFF_UP; } int loopback_setup(void) { _cleanup_netlink_unref_ sd_netlink *rtnl = NULL; int r; r = sd_netlink_open(&rtnl); if (r < 0) return r; r = start_loopback(rtnl); if (r < 0) { /* If we lack the permissions to configure the * loopback device, but we find it to be already * configured, let's exit cleanly, in order to * supported unprivileged containers. */ if (r == -EPERM && check_loopback(rtnl)) return 0; return log_warning_errno(r, "Failed to configure loopback device: %m"); } return 0; }