diff options
Diffstat (limited to 'lib/netns.c')
-rw-r--r-- | lib/netns.c | 147 |
1 files changed, 147 insertions, 0 deletions
diff --git a/lib/netns.c b/lib/netns.c new file mode 100644 index 0000000..6734b5d --- /dev/null +++ b/lib/netns.c @@ -0,0 +1,147 @@ +/* + * 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; + + sigfillset(&intmask); + sigprocmask(SIG_BLOCK, &intmask, oldmask); + + return setns(nsfd, CLONE_NEWNET); +} + +void restore_ns(sigset_t *oldmask) +{ + setns(default_nsfd, CLONE_NEWNET); + + sigprocmask(SIG_SETMASK, oldmask, NULL); +} + +int open_ns(int nsfd, const char *pathname, int flags) +{ + sigset_t intmask, oldmask; + int fd; + int errsv; + + sigfillset(&intmask); + sigprocmask(SIG_BLOCK, &intmask, &oldmask); + + setns(nsfd, CLONE_NEWNET); + fd = open(pathname, flags); + errsv = errno; + setns(default_nsfd, CLONE_NEWNET); + + sigprocmask(SIG_SETMASK, &oldmask, NULL); + + errno = errsv; + return fd; +} + +int socket_ns(int nsfd, int domain, int type, int protocol) +{ + sigset_t intmask, oldmask; + int sk; + int errsv; + + sigfillset(&intmask); + sigprocmask(SIG_BLOCK, &intmask, &oldmask); + + setns(nsfd, CLONE_NEWNET); + sk = socket(domain, type, protocol); + errsv = errno; + setns(default_nsfd, CLONE_NEWNET); + + sigprocmask(SIG_SETMASK, &oldmask, NULL); + + errno = errsv; + return sk; +} + +void init_netns() +{ + if ((default_nsfd = open("/proc/self/ns/net", O_RDONLY)) < 0) { + perror("init_netns"); + exit(EXIT_FAILURE); + } +} + +int get_nsfd(const char *name) +{ + int r; + sigset_t intmask, oldmask; + char path[MAXPATHLEN] = NETNS_PATH; + + r = mkdir(path, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH); + if (r < 0 && errno != EEXIST) + return r; + + snprintf(path, sizeof(path), "%s/%s", NETNS_PATH, name); + r = open(path, O_RDONLY|O_CREAT|O_EXCL, 0); + if (r < 0) { + if (errno == EEXIST) + return open(path, O_RDONLY); + + return r; + } + close(r); + + sigfillset(&intmask); + sigprocmask(SIG_BLOCK, &intmask, &oldmask); + + unshare(CLONE_NEWNET); + mount("/proc/self/ns/net", path, "none", MS_BIND, NULL); + + setns(default_nsfd, CLONE_NEWNET); + + sigprocmask(SIG_SETMASK, &oldmask, NULL); + + return open(path, O_RDONLY); +} + +#endif |