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/*
* Copyright (C) 2014-2017, Travelping GmbH <info@travelping.com>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* This program 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 Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
*/
#if defined(__linux__)
#ifdef HAVE_CONFIG_H
# include "config.h"
#endif
#ifndef _GNU_SOURCE
# define _GNU_SOURCE
#endif
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sched.h>
#include <signal.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/mount.h>
#include <sys/param.h>
#include <fcntl.h>
#include <errno.h>
#include "netns.h"
#define NETNS_PATH "/var/run/netns"
static int default_nsfd;
int switch_ns(int nsfd, sigset_t *oldmask)
{
sigset_t intmask;
int rc;
if (sigfillset(&intmask) < 0)
return -errno;
if ((rc = sigprocmask(SIG_BLOCK, &intmask, oldmask)) != 0)
return -rc;
if (setns(nsfd, CLONE_NEWNET) < 0)
return -errno;
return 0;
}
int restore_ns(sigset_t *oldmask)
{
int rc;
if (setns(default_nsfd, CLONE_NEWNET) < 0)
return -errno;
if ((rc = sigprocmask(SIG_SETMASK, oldmask, NULL)) != 0)
return -rc;
return 0;
}
int open_ns(int nsfd, const char *pathname, int flags)
{
sigset_t intmask, oldmask;
int fd;
int rc;
if (sigfillset(&intmask) < 0)
return -errno;
if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)
return -rc;
if (setns(nsfd, CLONE_NEWNET) < 0)
return -errno;
if ((fd = open(pathname, flags)) < 0)
return -errno;
if (setns(default_nsfd, CLONE_NEWNET) < 0) {
close(fd);
return -errno;
}
if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0) {
close(fd);
return -rc;
}
return fd;
}
int socket_ns(int nsfd, int domain, int type, int protocol)
{
sigset_t intmask, oldmask;
int sk;
int rc;
if (sigfillset(&intmask) < 0)
return -errno;
if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)
return -rc;
if (setns(nsfd, CLONE_NEWNET) < 0)
return -errno;
if ((sk = socket(domain, type, protocol)) < 0)
return -errno;
if (setns(default_nsfd, CLONE_NEWNET) < 0) {
close(sk);
return -errno;
}
if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0) {
close(sk);
return -rc;
}
return sk;
}
int init_netns()
{
if ((default_nsfd = open("/proc/self/ns/net", O_RDONLY)) < 0)
return -errno;
return 0;
}
int get_nsfd(const char *name)
{
int rc;
int fd;
sigset_t intmask, oldmask;
char path[MAXPATHLEN] = NETNS_PATH;
rc = mkdir(path, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
if (rc < 0 && errno != EEXIST)
return rc;
snprintf(path, sizeof(path), "%s/%s", NETNS_PATH, name);
fd = open(path, O_RDONLY|O_CREAT|O_EXCL, 0);
if (fd < 0) {
if (errno == EEXIST) {
if ((fd = open(path, O_RDONLY)) < 0)
return -errno;
return fd;
}
return -errno;
}
if (close(fd) < 0)
return -errno;
if (sigfillset(&intmask) < 0)
return -errno;
if ((rc = sigprocmask(SIG_BLOCK, &intmask, &oldmask)) != 0)
return -rc;
if (unshare(CLONE_NEWNET) < 0)
return -errno;
if (mount("/proc/self/ns/net", path, "none", MS_BIND, NULL) < 0)
return -errno;
if (setns(default_nsfd, CLONE_NEWNET) < 0)
return -errno;
if ((rc = sigprocmask(SIG_SETMASK, &oldmask, NULL)) != 0)
return -rc;
if ((fd = open(path, O_RDONLY)) < 0)
return -errno;
return fd;
}
#endif
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