109 lines
2.9 KiB
C
109 lines
2.9 KiB
C
/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
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/***
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This file is part of systemd.
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Copyright 2010 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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***/
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#include <sys/socket.h>
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#include <net/if.h>
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#include <asm/types.h>
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#include <netinet/in.h>
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#include <string.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include "util.h"
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#include "macro.h"
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#include "loopback-setup.h"
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#include "socket-util.h"
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#include "sd-rtnl.h"
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#include "rtnl-util.h"
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/* this is hardcoded in the kernel, so don't look it up */
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#define LOOPBACK_IFINDEX 1
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static int start_loopback(sd_rtnl *rtnl) {
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_cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
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int r;
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r = sd_rtnl_message_new_link(rtnl, &req, RTM_SETLINK, LOOPBACK_IFINDEX);
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if (r < 0)
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return r;
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r = sd_rtnl_message_link_set_flags(req, IFF_UP, IFF_UP);
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if (r < 0)
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return r;
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r = sd_rtnl_call(rtnl, req, 0, NULL);
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if (r < 0)
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return r;
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return 0;
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}
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static int check_loopback(void) {
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int r;
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_cleanup_close_ int fd = -1;
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union {
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struct sockaddr sa;
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struct sockaddr_in in;
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} sa = {
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.in.sin_family = AF_INET,
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.in.sin_addr.s_addr = INADDR_LOOPBACK,
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};
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/* If we failed to set up the loop back device, check whether
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* it might already be set up */
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fd = socket(AF_INET, SOCK_DGRAM|SOCK_NONBLOCK|SOCK_CLOEXEC, 0);
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if (fd < 0)
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return -errno;
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if (bind(fd, &sa.sa, sizeof(sa.in)) >= 0)
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r = 1;
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else
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r = errno == EADDRNOTAVAIL ? 0 : -errno;
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return r;
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}
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int loopback_setup(void) {
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_cleanup_rtnl_unref_ sd_rtnl *rtnl = NULL;
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int r;
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r = sd_rtnl_open(&rtnl, 0);
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if (r < 0)
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return r;
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r = start_loopback(rtnl);
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if (r == -EPERM) {
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if (check_loopback() < 0) {
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log_warning("Failed to configure loopback device: %s",
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strerror(EPERM));
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return -EPERM;
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}
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} else if (r < 0) {
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log_warning("Failed to configure loopback device: %s",
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strerror(-r));
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return r;
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}
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return 0;
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}
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