blob: e41a598a847fb24049e6d1a63a746be221816abe [file] [log] [blame]
#define _ATFILE_SOURCE
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/inotify.h>
#include <sys/mount.h>
#include <sys/param.h>
#include <sys/syscall.h>
#include <stdio.h>
#include <string.h>
#include <sched.h>
#include <fcntl.h>
#include <dirent.h>
#include <errno.h>
#include <unistd.h>
#include "utils.h"
#include "ip_common.h"
#define NETNS_RUN_DIR "/var/run/netns"
#define NETNS_ETC_DIR "/etc/netns"
#ifndef CLONE_NEWNET
#define CLONE_NEWNET 0x40000000 /* New network namespace (lo, device, names sockets, etc) */
#endif
#ifndef MNT_DETACH
#define MNT_DETACH 0x00000002 /* Just detach from the tree */
#endif /* MNT_DETACH */
#ifndef HAVE_SETNS
static int setns(int fd, int nstype)
{
#ifdef __NR_setns
return syscall(__NR_setns, fd, nstype);
#else
errno = ENOSYS;
return -1;
#endif
}
#endif /* HAVE_SETNS */
static void usage(void) __attribute__((noreturn));
static void usage(void)
{
fprintf(stderr, "Usage: ip netns list\n");
fprintf(stderr, " ip netns add NAME\n");
fprintf(stderr, " ip netns delete NAME\n");
fprintf(stderr, " ip netns exec NAME cmd ...\n");
fprintf(stderr, " ip netns monitor\n");
exit(-1);
}
int get_netns_fd(const char *name)
{
char pathbuf[MAXPATHLEN];
const char *path, *ptr;
path = name;
ptr = strchr(name, '/');
if (!ptr) {
snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
NETNS_RUN_DIR, name );
path = pathbuf;
}
return open(path, O_RDONLY);
}
static int netns_list(int argc, char **argv)
{
struct dirent *entry;
DIR *dir;
dir = opendir(NETNS_RUN_DIR);
if (!dir)
return 0;
while ((entry = readdir(dir)) != NULL) {
if (strcmp(entry->d_name, ".") == 0)
continue;
if (strcmp(entry->d_name, "..") == 0)
continue;
printf("%s\n", entry->d_name);
}
closedir(dir);
return 0;
}
static void bind_etc(const char *name)
{
char etc_netns_path[MAXPATHLEN];
char netns_name[MAXPATHLEN];
char etc_name[MAXPATHLEN];
struct dirent *entry;
DIR *dir;
snprintf(etc_netns_path, sizeof(etc_netns_path), "%s/%s", NETNS_ETC_DIR, name);
dir = opendir(etc_netns_path);
if (!dir)
return;
while ((entry = readdir(dir)) != NULL) {
if (strcmp(entry->d_name, ".") == 0)
continue;
if (strcmp(entry->d_name, "..") == 0)
continue;
snprintf(netns_name, sizeof(netns_name), "%s/%s", etc_netns_path, entry->d_name);
snprintf(etc_name, sizeof(etc_name), "/etc/%s", entry->d_name);
if (mount(netns_name, etc_name, "none", MS_BIND, NULL) < 0) {
fprintf(stderr, "Bind %s -> %s failed: %s\n",
netns_name, etc_name, strerror(errno));
}
}
closedir(dir);
}
static int netns_exec(int argc, char **argv)
{
/* Setup the proper environment for apps that are not netns
* aware, and execute a program in that environment.
*/
const char *name, *cmd;
char net_path[MAXPATHLEN];
int netns;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
if (argc < 2) {
fprintf(stderr, "No cmd specified\n");
return -1;
}
name = argv[0];
cmd = argv[1];
snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
netns = open(net_path, O_RDONLY);
if (netns < 0) {
fprintf(stderr, "Cannot open network namespace: %s\n",
strerror(errno));
return -1;
}
if (setns(netns, CLONE_NEWNET) < 0) {
fprintf(stderr, "seting the network namespace failed: %s\n",
strerror(errno));
return -1;
}
if (unshare(CLONE_NEWNS) < 0) {
fprintf(stderr, "unshare failed: %s\n", strerror(errno));
return -1;
}
/* Mount a version of /sys that describes the network namespace */
if (umount2("/sys", MNT_DETACH) < 0) {
fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
return -1;
}
if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
return -1;
}
/* Setup bind mounts for config files in /etc */
bind_etc(name);
if (execvp(cmd, argv + 1) < 0)
fprintf(stderr, "exec of %s failed: %s\n",
cmd, strerror(errno));
exit(-1);
}
static int netns_delete(int argc, char **argv)
{
const char *name;
char netns_path[MAXPATHLEN];
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
name = argv[0];
snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
umount2(netns_path, MNT_DETACH);
if (unlink(netns_path) < 0) {
fprintf(stderr, "Cannot remove %s: %s\n",
netns_path, strerror(errno));
return -1;
}
return 0;
}
static int netns_add(int argc, char **argv)
{
/* This function creates a new network namespace and
* a new mount namespace and bind them into a well known
* location in the filesystem based on the name provided.
*
* The mount namespace is created so that any necessary
* userspace tweaks like remounting /sys, or bind mounting
* a new /etc/resolv.conf can be shared between uers.
*/
char netns_path[MAXPATHLEN];
const char *name;
int fd;
if (argc < 1) {
fprintf(stderr, "No netns name specified\n");
return -1;
}
name = argv[0];
snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
/* Create the base netns directory if it doesn't exist */
mkdir(NETNS_RUN_DIR, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
/* Create the filesystem state */
fd = open(netns_path, O_RDONLY|O_CREAT|O_EXCL, 0);
if (fd < 0) {
fprintf(stderr, "Could not create %s: %s\n",
netns_path, strerror(errno));
return -1;
}
close(fd);
if (unshare(CLONE_NEWNET) < 0) {
fprintf(stderr, "Failed to create a new network namespace: %s\n",
strerror(errno));
goto out_delete;
}
/* Bind the netns last so I can watch for it */
if (mount("/proc/self/ns/net", netns_path, "none", MS_BIND, NULL) < 0) {
fprintf(stderr, "Bind /proc/self/ns/net -> %s failed: %s\n",
netns_path, strerror(errno));
goto out_delete;
}
return 0;
out_delete:
netns_delete(argc, argv);
exit(-1);
return -1;
}
static int netns_monitor(int argc, char **argv)
{
char buf[4096];
struct inotify_event *event;
int fd;
fd = inotify_init();
if (fd < 0) {
fprintf(stderr, "inotify_init failed: %s\n",
strerror(errno));
return -1;
}
if (inotify_add_watch(fd, NETNS_RUN_DIR, IN_CREATE | IN_DELETE) < 0) {
fprintf(stderr, "inotify_add_watch failed: %s\n",
strerror(errno));
return -1;
}
for(;;) {
ssize_t len = read(fd, buf, sizeof(buf));
if (len < 0) {
fprintf(stderr, "read failed: %s\n",
strerror(errno));
return -1;
}
for (event = (struct inotify_event *)buf;
(char *)event < &buf[len];
event = (struct inotify_event *)((char *)event + sizeof(*event) + event->len)) {
if (event->mask & IN_CREATE)
printf("add %s\n", event->name);
if (event->mask & IN_DELETE)
printf("delete %s\n", event->name);
}
}
return 0;
}
int do_netns(int argc, char **argv)
{
if (argc < 1)
return netns_list(0, NULL);
if ((matches(*argv, "list") == 0) || (matches(*argv, "show") == 0) ||
(matches(*argv, "lst") == 0))
return netns_list(argc-1, argv+1);
if (matches(*argv, "help") == 0)
usage();
if (matches(*argv, "add") == 0)
return netns_add(argc-1, argv+1);
if (matches(*argv, "delete") == 0)
return netns_delete(argc-1, argv+1);
if (matches(*argv, "exec") == 0)
return netns_exec(argc-1, argv+1);
if (matches(*argv, "monitor") == 0)
return netns_monitor(argc-1, argv+1);
fprintf(stderr, "Command \"%s\" is unknown, try \"ip netns help\".\n", *argv);
exit(-1);
}