148 lines
3.0 KiB
C
148 lines
3.0 KiB
C
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/*
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* Copyright (C) 2014-2017, Travelping GmbH <info@travelping.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as
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* published by the Free Software Foundation, either version 3 of the
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* License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*
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*/
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#if defined(__linux__)
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#ifndef _GNU_SOURCE
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# define _GNU_SOURCE
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#endif
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#include <errno.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <sched.h>
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#include <signal.h>
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <sys/socket.h>
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#include <sys/mount.h>
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#include <sys/param.h>
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#include <fcntl.h>
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#include <errno.h>
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#include "netns.h"
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#define NETNS_PATH "/var/run/netns"
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static int default_nsfd;
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int switch_ns(int nsfd, sigset_t *oldmask)
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{
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sigset_t intmask;
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sigfillset(&intmask);
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sigprocmask(SIG_BLOCK, &intmask, oldmask);
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return setns(nsfd, CLONE_NEWNET);
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}
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void restore_ns(sigset_t *oldmask)
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{
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setns(default_nsfd, CLONE_NEWNET);
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sigprocmask(SIG_SETMASK, oldmask, NULL);
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}
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int open_ns(int nsfd, const char *pathname, int flags)
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{
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sigset_t intmask, oldmask;
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int fd;
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int errsv;
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sigfillset(&intmask);
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sigprocmask(SIG_BLOCK, &intmask, &oldmask);
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setns(nsfd, CLONE_NEWNET);
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fd = open(pathname, flags);
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errsv = errno;
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setns(default_nsfd, CLONE_NEWNET);
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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errno = errsv;
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return fd;
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}
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int socket_ns(int nsfd, int domain, int type, int protocol)
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{
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sigset_t intmask, oldmask;
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int sk;
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int errsv;
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sigfillset(&intmask);
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sigprocmask(SIG_BLOCK, &intmask, &oldmask);
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setns(nsfd, CLONE_NEWNET);
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sk = socket(domain, type, protocol);
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errsv = errno;
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setns(default_nsfd, CLONE_NEWNET);
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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errno = errsv;
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return sk;
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}
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void init_netns()
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{
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if ((default_nsfd = open("/proc/self/ns/net", O_RDONLY)) < 0) {
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perror("init_netns");
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exit(EXIT_FAILURE);
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}
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}
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int get_nsfd(const char *name)
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{
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int r;
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sigset_t intmask, oldmask;
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char path[MAXPATHLEN] = NETNS_PATH;
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r = mkdir(path, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
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if (r < 0 && errno != EEXIST)
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return r;
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snprintf(path, sizeof(path), "%s/%s", NETNS_PATH, name);
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r = open(path, O_RDONLY|O_CREAT|O_EXCL, 0);
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if (r < 0) {
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if (errno == EEXIST)
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return open(path, O_RDONLY);
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return r;
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}
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close(r);
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sigfillset(&intmask);
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sigprocmask(SIG_BLOCK, &intmask, &oldmask);
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unshare(CLONE_NEWNET);
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mount("/proc/self/ns/net", path, "none", MS_BIND, NULL);
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setns(default_nsfd, CLONE_NEWNET);
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sigprocmask(SIG_SETMASK, &oldmask, NULL);
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return open(path, O_RDONLY);
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}
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#endif
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