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/*-*- 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 <sys/socket.h>
#include <net/if.h>
#include <asm/types.h>
#include <netinet/in.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#include "util.h"
#include "macro.h"
#include "loopback-setup.h"
#include "socket-util.h"
#include "sd-rtnl.h"
#include "rtnl-util.h"
/* this is hardcoded in the kernel, so don't look it up */
#define LOOPBACK_IFINDEX 1
static int start_loopback(sd_rtnl *rtnl) {
_cleanup_rtnl_message_unref_ sd_rtnl_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_rtnl_call(rtnl, req, 0, NULL);
if (r < 0)
return r;
return 0;
}
static int check_loopback(void) {
int r;
_cleanup_close_ int fd = -1;
union {
struct sockaddr sa;
struct sockaddr_in in;
} sa = {
.in.sin_family = AF_INET,
.in.sin_addr.s_addr = INADDR_LOOPBACK,
};
/* If we failed to set up the loop back device, check whether
* it might already be set up */
fd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
if (fd < 0)
return -errno;
if (bind(fd, &sa.sa, sizeof(sa.in)) >= 0)
r = 1;
else
r = errno == EADDRNOTAVAIL ? 0 : -errno;
return r;
}
int loopback_setup(void) {
_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
int r;
r = sd_rtnl_open(&rtnl, 0);
if (r < 0)
return r;
r = start_loopback(rtnl);
if (r == -EPERM) {
if (check_loopback() < 0) {
log_warning_errno(EPERM, "Failed to configure loopback device: %m");
return -EPERM;
}
} else if (r < 0) {
log_warning_errno(r, "Failed to configure loopback device: %m");
return r;
}
return 0;
}
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