5 #include <sys/inotify.h>
8 #include <sys/syscall.h>
18 #include "ip_common.h"
20 #define NETNS_RUN_DIR "/var/run/netns"
21 #define NETNS_ETC_DIR "/etc/netns"
24 #define CLONE_NEWNET 0x40000000 /* New network namespace (lo, device, names sockets, etc) */
28 #define MNT_DETACH 0x00000002 /* Just detach from the tree */
29 #endif /* MNT_DETACH */
32 static int setns(int fd, int nstype)
35 return syscall(__NR_setns, fd, nstype);
41 #endif /* HAVE_SETNS */
44 static void usage(void) __attribute__((noreturn));
46 static void usage(void)
48 fprintf(stderr, "Usage: ip netns list\n");
49 fprintf(stderr, " ip netns add NAME\n");
50 fprintf(stderr, " ip netns delete NAME\n");
51 fprintf(stderr, " ip netns exec NAME cmd ...\n");
52 fprintf(stderr, " ip netns monitor\n");
56 int get_netns_fd(const char *name)
58 char pathbuf[MAXPATHLEN];
59 const char *path, *ptr;
62 ptr = strchr(name, '/');
64 snprintf(pathbuf, sizeof(pathbuf), "%s/%s",
65 NETNS_RUN_DIR, name );
68 return open(path, O_RDONLY);
71 static int netns_list(int argc, char **argv)
76 dir = opendir(NETNS_RUN_DIR);
80 while ((entry = readdir(dir)) != NULL) {
81 if (strcmp(entry->d_name, ".") == 0)
83 if (strcmp(entry->d_name, "..") == 0)
85 printf("%s\n", entry->d_name);
91 static void bind_etc(const char *name)
93 char etc_netns_path[MAXPATHLEN];
94 char netns_name[MAXPATHLEN];
95 char etc_name[MAXPATHLEN];
99 snprintf(etc_netns_path, sizeof(etc_netns_path), "%s/%s", NETNS_ETC_DIR, name);
100 dir = opendir(etc_netns_path);
104 while ((entry = readdir(dir)) != NULL) {
105 if (strcmp(entry->d_name, ".") == 0)
107 if (strcmp(entry->d_name, "..") == 0)
109 snprintf(netns_name, sizeof(netns_name), "%s/%s", etc_netns_path, entry->d_name);
110 snprintf(etc_name, sizeof(etc_name), "/etc/%s", entry->d_name);
111 if (mount(netns_name, etc_name, "none", MS_BIND, NULL) < 0) {
112 fprintf(stderr, "Bind %s -> %s failed: %s\n",
113 netns_name, etc_name, strerror(errno));
119 static int netns_exec(int argc, char **argv)
121 /* Setup the proper environment for apps that are not netns
122 * aware, and execute a program in that environment.
124 const char *name, *cmd;
125 char net_path[MAXPATHLEN];
129 fprintf(stderr, "No netns name specified\n");
133 fprintf(stderr, "No cmd specified\n");
138 snprintf(net_path, sizeof(net_path), "%s/%s", NETNS_RUN_DIR, name);
139 netns = open(net_path, O_RDONLY);
141 fprintf(stderr, "Cannot open network namespace: %s\n",
145 if (setns(netns, CLONE_NEWNET) < 0) {
146 fprintf(stderr, "seting the network namespace failed: %s\n",
151 if (unshare(CLONE_NEWNS) < 0) {
152 fprintf(stderr, "unshare failed: %s\n", strerror(errno));
155 /* Mount a version of /sys that describes the network namespace */
156 if (umount2("/sys", MNT_DETACH) < 0) {
157 fprintf(stderr, "umount of /sys failed: %s\n", strerror(errno));
160 if (mount(name, "/sys", "sysfs", 0, NULL) < 0) {
161 fprintf(stderr, "mount of /sys failed: %s\n",strerror(errno));
165 /* Setup bind mounts for config files in /etc */
168 if (execvp(cmd, argv + 1) < 0)
169 fprintf(stderr, "exec of %s failed: %s\n",
170 cmd, strerror(errno));
174 static int netns_delete(int argc, char **argv)
177 char netns_path[MAXPATHLEN];
180 fprintf(stderr, "No netns name specified\n");
185 snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
186 umount2(netns_path, MNT_DETACH);
187 if (unlink(netns_path) < 0) {
188 fprintf(stderr, "Cannot remove %s: %s\n",
189 netns_path, strerror(errno));
195 static int netns_add(int argc, char **argv)
197 /* This function creates a new network namespace and
198 * a new mount namespace and bind them into a well known
199 * location in the filesystem based on the name provided.
201 * The mount namespace is created so that any necessary
202 * userspace tweaks like remounting /sys, or bind mounting
203 * a new /etc/resolv.conf can be shared between uers.
205 char netns_path[MAXPATHLEN];
210 fprintf(stderr, "No netns name specified\n");
215 snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
217 /* Create the base netns directory if it doesn't exist */
218 mkdir(NETNS_RUN_DIR, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH);
220 /* Create the filesystem state */
221 fd = open(netns_path, O_RDONLY|O_CREAT|O_EXCL, 0);
223 fprintf(stderr, "Could not create %s: %s\n",
224 netns_path, strerror(errno));
228 if (unshare(CLONE_NEWNET) < 0) {
229 fprintf(stderr, "Failed to create a new network namespace: %s\n",
234 /* Bind the netns last so I can watch for it */
235 if (mount("/proc/self/ns/net", netns_path, "none", MS_BIND, NULL) < 0) {
236 fprintf(stderr, "Bind /proc/self/ns/net -> %s failed: %s\n",
237 netns_path, strerror(errno));
242 netns_delete(argc, argv);
248 static int netns_monitor(int argc, char **argv)
251 struct inotify_event *event;
255 fprintf(stderr, "inotify_init failed: %s\n",
259 if (inotify_add_watch(fd, NETNS_RUN_DIR, IN_CREATE | IN_DELETE) < 0) {
260 fprintf(stderr, "inotify_add_watch failed: %s\n",
265 ssize_t len = read(fd, buf, sizeof(buf));
267 fprintf(stderr, "read failed: %s\n",
271 for (event = (struct inotify_event *)buf;
272 (char *)event < &buf[len];
273 event = (struct inotify_event *)((char *)event + sizeof(*event) + event->len)) {
274 if (event->mask & IN_CREATE)
275 printf("add %s\n", event->name);
276 if (event->mask & IN_DELETE)
277 printf("delete %s\n", event->name);
283 int do_netns(int argc, char **argv)
286 return netns_list(0, NULL);
288 if ((matches(*argv, "list") == 0) || (matches(*argv, "show") == 0) ||
289 (matches(*argv, "lst") == 0))
290 return netns_list(argc-1, argv+1);
292 if (matches(*argv, "help") == 0)
295 if (matches(*argv, "add") == 0)
296 return netns_add(argc-1, argv+1);
298 if (matches(*argv, "delete") == 0)
299 return netns_delete(argc-1, argv+1);
301 if (matches(*argv, "exec") == 0)
302 return netns_exec(argc-1, argv+1);
304 if (matches(*argv, "monitor") == 0)
305 return netns_monitor(argc-1, argv+1);
307 fprintf(stderr, "Command \"%s\" is unknown, try \"ip netns help\".\n", *argv);