mirror_iproute2/lib/namespace.c
Vadim Kochan eb67e4498a lib: Add netns_switch func for change network namespace
New netns_switch func moved to the lib/namespace.c from ip/ipnetns.c
so it can be used from the other tools for fast switching
network namespace.

Signed-off-by: Vadim Kochan <vadim4j@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
2014-12-27 10:22:27 -08:00

87 lines
2.3 KiB
C

/*
* namespace.c
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <fcntl.h>
#include <dirent.h>
#include "utils.h"
#include "namespace.h"
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);
}
int netns_switch(char *name)
{
char net_path[MAXPATHLEN];
int netns;
snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
netns = open(net_path, O_RDONLY | O_CLOEXEC);
if (netns < 0) {
fprintf(stderr, "Cannot open network namespace \"%s\": %s\n",
name, strerror(errno));
return -1;
}
if (setns(netns, CLONE_NEWNET) < 0) {
fprintf(stderr, "setting the network namespace \"%s\" failed: %s\n",
name, strerror(errno));
return -1;
}
if (unshare(CLONE_NEWNS) < 0) {
fprintf(stderr, "unshare failed: %s\n", strerror(errno));
return -1;
}
/* Don't let any mounts propagate back to the parent */
if (mount("", "/", "none", MS_SLAVE | MS_REC, NULL)) {
fprintf(stderr, "\"mount --make-rslave /\" 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);
return 0;
}