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/***
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 "basic/missing.h"
#include "sd-netlink/sd-netlink.h"
#include "loopback-setup.h"
static int start_loopback(sd_netlink *rtnl) {
_cleanup_(sd_netlink_message_unrefp) 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_(sd_netlink_message_unrefp) 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_(sd_netlink_unrefp) 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;
}
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