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-rw-r--r--ip/ipnetns.c1103
1 files changed, 1103 insertions, 0 deletions
diff --git a/ip/ipnetns.c b/ip/ipnetns.c
new file mode 100644
index 0000000..1203534
--- /dev/null
+++ b/ip/ipnetns.c
@@ -0,0 +1,1103 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#define _ATFILE_SOURCE
+#include <sys/file.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/wait.h>
+#include <sys/inotify.h>
+#include <sys/mount.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 <ctype.h>
+#include <linux/limits.h>
+
+#include <linux/net_namespace.h>
+
+#include "utils.h"
+#include "list.h"
+#include "ip_common.h"
+#include "namespace.h"
+#include "json_print.h"
+
+static int usage(void)
+{
+ fprintf(stderr,
+ "Usage: ip netns list\n"
+ " ip netns add NAME\n"
+ " ip netns attach NAME PID\n"
+ " ip netns set NAME NETNSID\n"
+ " ip [-all] netns delete [NAME]\n"
+ " ip netns identify [PID]\n"
+ " ip netns pids NAME\n"
+ " ip [-all] netns exec [NAME] cmd ...\n"
+ " ip netns monitor\n"
+ " ip netns list-id [target-nsid POSITIVE-INT] [nsid POSITIVE-INT]\n"
+ "NETNSID := auto | POSITIVE-INT\n");
+ exit(-1);
+}
+
+/* This socket is used to get nsid */
+static struct rtnl_handle rtnsh = { .fd = -1 };
+
+static int have_rtnl_getnsid = -1;
+static int saved_netns = -1;
+static struct link_filter filter;
+
+static int ipnetns_accept_msg(struct rtnl_ctrl_data *ctrl,
+ struct nlmsghdr *n, void *arg)
+{
+ struct nlmsgerr *err = (struct nlmsgerr *)NLMSG_DATA(n);
+
+ if (n->nlmsg_type == NLMSG_ERROR &&
+ (err->error == -EOPNOTSUPP || err->error == -EINVAL))
+ have_rtnl_getnsid = 0;
+ else
+ have_rtnl_getnsid = 1;
+ return -1;
+}
+
+static int ipnetns_have_nsid(void)
+{
+ struct {
+ struct nlmsghdr n;
+ struct rtgenmsg g;
+ char buf[1024];
+ } req = {
+ .n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
+ .n.nlmsg_flags = NLM_F_REQUEST,
+ .n.nlmsg_type = RTM_GETNSID,
+ .g.rtgen_family = AF_UNSPEC,
+ };
+ int fd;
+
+ if (have_rtnl_getnsid >= 0) {
+ fd = open("/proc/self/ns/net", O_RDONLY);
+ if (fd < 0) {
+ fprintf(stderr,
+ "/proc/self/ns/net: %s. Continuing anyway.\n",
+ strerror(errno));
+ have_rtnl_getnsid = 0;
+ return 0;
+ }
+
+ addattr32(&req.n, 1024, NETNSA_FD, fd);
+
+ if (rtnl_send(&rth, &req.n, req.n.nlmsg_len) < 0) {
+ fprintf(stderr,
+ "rtnl_send(RTM_GETNSID): %s. Continuing anyway.\n",
+ strerror(errno));
+ have_rtnl_getnsid = 0;
+ close(fd);
+ return 0;
+ }
+ rtnl_listen(&rth, ipnetns_accept_msg, NULL);
+ close(fd);
+ }
+
+ return have_rtnl_getnsid;
+}
+
+int get_netnsid_from_name(const char *name)
+{
+ struct {
+ struct nlmsghdr n;
+ struct rtgenmsg g;
+ char buf[1024];
+ } req = {
+ .n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
+ .n.nlmsg_flags = NLM_F_REQUEST,
+ .n.nlmsg_type = RTM_GETNSID,
+ .g.rtgen_family = AF_UNSPEC,
+ };
+ struct nlmsghdr *answer;
+ struct rtattr *tb[NETNSA_MAX + 1];
+ struct rtgenmsg *rthdr;
+ int len, fd, ret = -1;
+
+ netns_nsid_socket_init();
+
+ fd = netns_get_fd(name);
+ if (fd < 0)
+ return fd;
+
+ addattr32(&req.n, 1024, NETNSA_FD, fd);
+ if (rtnl_talk(&rtnsh, &req.n, &answer) < 0) {
+ close(fd);
+ return -2;
+ }
+ close(fd);
+
+ /* Validate message and parse attributes */
+ if (answer->nlmsg_type == NLMSG_ERROR)
+ goto out;
+
+ rthdr = NLMSG_DATA(answer);
+ len = answer->nlmsg_len - NLMSG_SPACE(sizeof(*rthdr));
+ if (len < 0)
+ goto out;
+
+ parse_rtattr(tb, NETNSA_MAX, NETNS_RTA(rthdr), len);
+
+ if (tb[NETNSA_NSID]) {
+ ret = rta_getattr_s32(tb[NETNSA_NSID]);
+ }
+
+out:
+ free(answer);
+ return ret;
+}
+
+struct nsid_cache {
+ struct hlist_node nsid_hash;
+ struct hlist_node name_hash;
+ int nsid;
+ char name[0];
+};
+
+#define NSIDMAP_SIZE 128
+#define NSID_HASH_NSID(nsid) (nsid & (NSIDMAP_SIZE - 1))
+#define NSID_HASH_NAME(name) (namehash(name) & (NSIDMAP_SIZE - 1))
+
+static struct hlist_head nsid_head[NSIDMAP_SIZE];
+static struct hlist_head name_head[NSIDMAP_SIZE];
+
+static struct nsid_cache *netns_map_get_by_nsid(int nsid)
+{
+ struct hlist_node *n;
+ uint32_t h;
+
+ if (nsid < 0)
+ return NULL;
+
+ h = NSID_HASH_NSID(nsid);
+ hlist_for_each(n, &nsid_head[h]) {
+ struct nsid_cache *c = container_of(n, struct nsid_cache,
+ nsid_hash);
+ if (c->nsid == nsid)
+ return c;
+ }
+
+ return NULL;
+}
+
+char *get_name_from_nsid(int nsid)
+{
+ struct nsid_cache *c;
+
+ if (nsid < 0)
+ return NULL;
+
+ netns_nsid_socket_init();
+ netns_map_init();
+
+ c = netns_map_get_by_nsid(nsid);
+ if (c)
+ return c->name;
+
+ return NULL;
+}
+
+static int netns_map_add(int nsid, const char *name)
+{
+ struct nsid_cache *c;
+ uint32_t h;
+
+ if (netns_map_get_by_nsid(nsid) != NULL)
+ return -EEXIST;
+
+ c = malloc(sizeof(*c) + strlen(name) + 1);
+ if (c == NULL) {
+ perror("malloc");
+ return -ENOMEM;
+ }
+ c->nsid = nsid;
+ strcpy(c->name, name);
+
+ h = NSID_HASH_NSID(nsid);
+ hlist_add_head(&c->nsid_hash, &nsid_head[h]);
+
+ h = NSID_HASH_NAME(name);
+ hlist_add_head(&c->name_hash, &name_head[h]);
+
+ return 0;
+}
+
+static void netns_map_del(struct nsid_cache *c)
+{
+ hlist_del(&c->name_hash);
+ hlist_del(&c->nsid_hash);
+ free(c);
+}
+
+void netns_nsid_socket_init(void)
+{
+ if (rtnsh.fd > -1 || !ipnetns_have_nsid())
+ return;
+
+ if (rtnl_open(&rtnsh, 0) < 0) {
+ fprintf(stderr, "Cannot open rtnetlink\n");
+ exit(1);
+ }
+
+}
+
+void netns_map_init(void)
+{
+ static int initialized;
+ struct dirent *entry;
+ DIR *dir;
+ int nsid;
+
+ if (initialized || !ipnetns_have_nsid())
+ return;
+
+ dir = opendir(NETNS_RUN_DIR);
+ if (!dir)
+ return;
+
+ while ((entry = readdir(dir)) != NULL) {
+ if (strcmp(entry->d_name, ".") == 0)
+ continue;
+ if (strcmp(entry->d_name, "..") == 0)
+ continue;
+ nsid = get_netnsid_from_name(entry->d_name);
+
+ if (nsid >= 0)
+ netns_map_add(nsid, entry->d_name);
+ }
+ closedir(dir);
+ initialized = 1;
+}
+
+static int netns_get_name(int nsid, char *name)
+{
+ struct dirent *entry;
+ DIR *dir;
+ int id;
+
+ if (nsid < 0)
+ return -EINVAL;
+
+ dir = opendir(NETNS_RUN_DIR);
+ if (!dir)
+ return -ENOENT;
+
+ while ((entry = readdir(dir)) != NULL) {
+ if (strcmp(entry->d_name, ".") == 0)
+ continue;
+ if (strcmp(entry->d_name, "..") == 0)
+ continue;
+ id = get_netnsid_from_name(entry->d_name);
+
+ if (id >= 0 && nsid == id) {
+ strcpy(name, entry->d_name);
+ closedir(dir);
+ return 0;
+ }
+ }
+ closedir(dir);
+ return -ENOENT;
+}
+
+int print_nsid(struct nlmsghdr *n, void *arg)
+{
+ struct rtgenmsg *rthdr = NLMSG_DATA(n);
+ struct rtattr *tb[NETNSA_MAX+1];
+ int len = n->nlmsg_len;
+ FILE *fp = (FILE *)arg;
+ struct nsid_cache *c;
+ char name[NAME_MAX];
+ int nsid, current;
+
+ if (n->nlmsg_type != RTM_NEWNSID && n->nlmsg_type != RTM_DELNSID)
+ return 0;
+
+ len -= NLMSG_SPACE(sizeof(*rthdr));
+ if (len < 0) {
+ fprintf(stderr, "BUG: wrong nlmsg len %d in %s\n", len,
+ __func__);
+ return -1;
+ }
+
+ parse_rtattr(tb, NETNSA_MAX, NETNS_RTA(rthdr), len);
+ if (tb[NETNSA_NSID] == NULL) {
+ fprintf(stderr, "BUG: NETNSA_NSID is missing %s\n", __func__);
+ return -1;
+ }
+
+ open_json_object(NULL);
+ if (n->nlmsg_type == RTM_DELNSID)
+ print_bool(PRINT_ANY, "deleted", "Deleted ", true);
+
+ nsid = rta_getattr_s32(tb[NETNSA_NSID]);
+ if (nsid < 0)
+ print_string(PRINT_FP, NULL, "nsid unassigned ", NULL);
+ else
+ print_int(PRINT_ANY, "nsid", "nsid %d ", nsid);
+
+ if (tb[NETNSA_CURRENT_NSID]) {
+ current = rta_getattr_s32(tb[NETNSA_CURRENT_NSID]);
+ if (current < 0)
+ print_string(PRINT_FP, NULL,
+ "current-nsid unassigned ", NULL);
+ else
+ print_int(PRINT_ANY, "current-nsid",
+ "current-nsid %d ", current);
+ }
+
+ c = netns_map_get_by_nsid(tb[NETNSA_CURRENT_NSID] ? current : nsid);
+ if (c != NULL) {
+ print_string(PRINT_ANY, "name",
+ "(iproute2 netns name: %s)", c->name);
+ netns_map_del(c);
+ }
+
+ /* nsid might not be in cache */
+ if (c == NULL && n->nlmsg_type == RTM_NEWNSID)
+ if (netns_get_name(nsid, name) == 0) {
+ print_string(PRINT_ANY, "name",
+ "(iproute2 netns name: %s)", name);
+ netns_map_add(nsid, name);
+ }
+
+ print_string(PRINT_FP, NULL, "\n", NULL);
+ close_json_object();
+ fflush(fp);
+ return 0;
+}
+
+static int get_netnsid_from_netnsid(int nsid)
+{
+ struct {
+ struct nlmsghdr n;
+ struct rtgenmsg g;
+ char buf[1024];
+ } req = {
+ .n.nlmsg_len = NLMSG_LENGTH(NLMSG_ALIGN(sizeof(struct rtgenmsg))),
+ .n.nlmsg_flags = NLM_F_REQUEST,
+ .n.nlmsg_type = RTM_GETNSID,
+ .g.rtgen_family = AF_UNSPEC,
+ };
+ struct nlmsghdr *answer;
+ int err;
+
+ netns_nsid_socket_init();
+
+ err = addattr32(&req.n, sizeof(req), NETNSA_NSID, nsid);
+ if (err)
+ return err;
+
+ if (filter.target_nsid >= 0) {
+ err = addattr32(&req.n, sizeof(req), NETNSA_TARGET_NSID,
+ filter.target_nsid);
+ if (err)
+ return err;
+ }
+
+ if (rtnl_talk(&rtnsh, &req.n, &answer) < 0)
+ return -2;
+
+ /* Validate message and parse attributes */
+ if (answer->nlmsg_type == NLMSG_ERROR)
+ goto err_out;
+
+ new_json_obj(json);
+ err = print_nsid(answer, stdout);
+ delete_json_obj();
+err_out:
+ free(answer);
+ return err;
+}
+
+static int netns_filter_req(struct nlmsghdr *nlh, int reqlen)
+{
+ int err;
+
+ if (filter.target_nsid >= 0) {
+ err = addattr32(nlh, reqlen, NETNSA_TARGET_NSID,
+ filter.target_nsid);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+static int netns_list_id(int argc, char **argv)
+{
+ int nsid = -1;
+
+ if (!ipnetns_have_nsid()) {
+ fprintf(stderr,
+ "RTM_GETNSID is not supported by the kernel.\n");
+ return -ENOTSUP;
+ }
+
+ filter.target_nsid = -1;
+ while (argc > 0) {
+ if (strcmp(*argv, "target-nsid") == 0) {
+ if (filter.target_nsid >= 0)
+ duparg("target-nsid", *argv);
+ NEXT_ARG();
+
+ if (get_integer(&filter.target_nsid, *argv, 0))
+ invarg("\"target-nsid\" value is invalid",
+ *argv);
+ else if (filter.target_nsid < 0)
+ invarg("\"target-nsid\" value should be >= 0",
+ argv[1]);
+ } else if (strcmp(*argv, "nsid") == 0) {
+ if (nsid >= 0)
+ duparg("nsid", *argv);
+ NEXT_ARG();
+
+ if (get_integer(&nsid, *argv, 0))
+ invarg("\"nsid\" value is invalid", *argv);
+ else if (nsid < 0)
+ invarg("\"nsid\" value should be >= 0",
+ argv[1]);
+ } else
+ usage();
+ argc--; argv++;
+ }
+
+ if (nsid >= 0)
+ return get_netnsid_from_netnsid(nsid);
+
+ if (rtnl_nsiddump_req_filter_fn(&rth, AF_UNSPEC,
+ netns_filter_req) < 0) {
+ perror("Cannot send dump request");
+ exit(1);
+ }
+
+ new_json_obj(json);
+ if (rtnl_dump_filter(&rth, print_nsid, stdout) < 0) {
+ delete_json_obj();
+ fprintf(stderr, "Dump terminated\n");
+ exit(1);
+ }
+ delete_json_obj();
+ return 0;
+}
+
+static int netns_list(int argc, char **argv)
+{
+ struct dirent *entry;
+ DIR *dir;
+ int id;
+
+ dir = opendir(NETNS_RUN_DIR);
+ if (!dir)
+ return 0;
+
+ new_json_obj(json);
+ while ((entry = readdir(dir)) != NULL) {
+ if (strcmp(entry->d_name, ".") == 0)
+ continue;
+ if (strcmp(entry->d_name, "..") == 0)
+ continue;
+
+ open_json_object(NULL);
+ print_string(PRINT_ANY, "name",
+ "%s", entry->d_name);
+ if (ipnetns_have_nsid()) {
+ id = get_netnsid_from_name(entry->d_name);
+ if (id >= 0)
+ print_int(PRINT_ANY, "id", " (id: %d)", id);
+ }
+ print_string(PRINT_FP, NULL, "\n", NULL);
+ close_json_object();
+ }
+ closedir(dir);
+ delete_json_obj();
+ return 0;
+}
+
+static int do_switch(void *arg)
+{
+ char *netns = arg;
+
+ /* we just changed namespaces. clear any vrf association
+ * with prior namespace before exec'ing command
+ */
+ vrf_reset();
+
+ return netns_switch(netns);
+}
+
+static int on_netns_exec(char *nsname, void *arg)
+{
+ char **argv = arg;
+
+ printf("\nnetns: %s\n", nsname);
+ cmd_exec(argv[0], argv, true, do_switch, nsname);
+ return 0;
+}
+
+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.
+ */
+ if (argc < 1 && !do_all) {
+ fprintf(stderr, "No netns name specified\n");
+ return -1;
+ }
+ if ((argc < 2 && !do_all) || (argc < 1 && do_all)) {
+ fprintf(stderr, "No command specified\n");
+ return -1;
+ }
+
+ if (do_all)
+ return netns_foreach(on_netns_exec, argv);
+
+ /* ip must return the status of the child,
+ * but do_cmd() will add a minus to this,
+ * so let's add another one here to cancel it.
+ */
+ return -cmd_exec(argv[1], argv + 1, !!batch_mode, do_switch, argv[0]);
+}
+
+static int is_pid(const char *str)
+{
+ int ch;
+
+ for (; (ch = *str); str++) {
+ if (!isdigit(ch))
+ return 0;
+ }
+ return 1;
+}
+
+static int netns_pids(int argc, char **argv)
+{
+ const char *name;
+ char net_path[PATH_MAX];
+ int netns = -1, ret = -1;
+ struct stat netst;
+ DIR *dir;
+ struct dirent *entry;
+
+ if (argc < 1) {
+ fprintf(stderr, "No netns name specified\n");
+ goto out;
+ }
+ if (argc > 1) {
+ fprintf(stderr, "extra arguments specified\n");
+ goto out;
+ }
+
+ name = argv[0];
+ 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));
+ goto out;
+ }
+ if (fstat(netns, &netst) < 0) {
+ fprintf(stderr, "Stat of netns failed: %s\n",
+ strerror(errno));
+ goto out;
+ }
+ dir = opendir("/proc/");
+ if (!dir) {
+ fprintf(stderr, "Open of /proc failed: %s\n",
+ strerror(errno));
+ goto out;
+ }
+ while ((entry = readdir(dir))) {
+ char pid_net_path[PATH_MAX];
+ struct stat st;
+
+ if (!is_pid(entry->d_name))
+ continue;
+ snprintf(pid_net_path, sizeof(pid_net_path), "/proc/%s/ns/net",
+ entry->d_name);
+ if (stat(pid_net_path, &st) != 0)
+ continue;
+ if ((st.st_dev == netst.st_dev) &&
+ (st.st_ino == netst.st_ino)) {
+ printf("%s\n", entry->d_name);
+ }
+ }
+ ret = 0;
+ closedir(dir);
+out:
+ if (netns >= 0)
+ close(netns);
+ return ret;
+
+}
+
+int netns_identify_pid(const char *pidstr, char *name, int len)
+{
+ char net_path[PATH_MAX];
+ int netns = -1, ret = -1;
+ struct stat netst;
+ DIR *dir;
+ struct dirent *entry;
+
+ name[0] = '\0';
+
+ snprintf(net_path, sizeof(net_path), "/proc/%s/ns/net", pidstr);
+ netns = open(net_path, O_RDONLY);
+ if (netns < 0) {
+ fprintf(stderr, "Cannot open network namespace: %s\n",
+ strerror(errno));
+ goto out;
+ }
+ if (fstat(netns, &netst) < 0) {
+ fprintf(stderr, "Stat of netns failed: %s\n",
+ strerror(errno));
+ goto out;
+ }
+ dir = opendir(NETNS_RUN_DIR);
+ if (!dir) {
+ /* Succeed treat a missing directory as an empty directory */
+ if (errno == ENOENT) {
+ ret = 0;
+ goto out;
+ }
+
+ fprintf(stderr, "Failed to open directory %s:%s\n",
+ NETNS_RUN_DIR, strerror(errno));
+ goto out;
+ }
+
+ while ((entry = readdir(dir))) {
+ char name_path[PATH_MAX];
+ struct stat st;
+
+ if (strcmp(entry->d_name, ".") == 0)
+ continue;
+ if (strcmp(entry->d_name, "..") == 0)
+ continue;
+
+ snprintf(name_path, sizeof(name_path), "%s/%s", NETNS_RUN_DIR,
+ entry->d_name);
+
+ if (stat(name_path, &st) != 0)
+ continue;
+
+ if ((st.st_dev == netst.st_dev) &&
+ (st.st_ino == netst.st_ino)) {
+ strlcpy(name, entry->d_name, len);
+ }
+ }
+ ret = 0;
+ closedir(dir);
+out:
+ if (netns >= 0)
+ close(netns);
+ return ret;
+
+}
+
+static int netns_identify(int argc, char **argv)
+{
+ const char *pidstr;
+ char name[256];
+ int rc;
+
+ if (argc < 1) {
+ pidstr = "self";
+ } else if (argc > 1) {
+ fprintf(stderr, "extra arguments specified\n");
+ return -1;
+ } else {
+ pidstr = argv[0];
+ if (!is_pid(pidstr)) {
+ fprintf(stderr, "Specified string '%s' is not a pid\n",
+ pidstr);
+ return -1;
+ }
+ }
+
+ rc = netns_identify_pid(pidstr, name, sizeof(name));
+ if (!rc)
+ printf("%s\n", name);
+
+ return rc;
+}
+
+static int on_netns_del(char *nsname, void *arg)
+{
+ char netns_path[PATH_MAX];
+
+ snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, nsname);
+ umount2(netns_path, MNT_DETACH);
+ if (unlink(netns_path) < 0) {
+ fprintf(stderr, "Cannot remove namespace file \"%s\": %s\n",
+ netns_path, strerror(errno));
+ return -1;
+ }
+ return 0;
+}
+
+static int netns_delete(int argc, char **argv)
+{
+ if (argc < 1 && !do_all) {
+ fprintf(stderr, "No netns name specified\n");
+ return -1;
+ }
+
+ if (do_all)
+ return netns_foreach(on_netns_del, NULL);
+
+ return on_netns_del(argv[0], NULL);
+}
+
+static int create_netns_dir(void)
+{
+ /* Create the base netns directory if it doesn't exist */
+ if (mkdir(NETNS_RUN_DIR, S_IRWXU|S_IRGRP|S_IXGRP|S_IROTH|S_IXOTH)) {
+ if (errno != EEXIST) {
+ fprintf(stderr, "mkdir %s failed: %s\n",
+ NETNS_RUN_DIR, strerror(errno));
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+/* Obtain a FD for the current namespace, so we can reenter it later */
+static void netns_save(void)
+{
+ if (saved_netns != -1)
+ return;
+
+ saved_netns = open("/proc/self/ns/net", O_RDONLY | O_CLOEXEC);
+ if (saved_netns == -1) {
+ perror("Cannot open init namespace");
+ exit(1);
+ }
+}
+
+static void netns_restore(void)
+{
+ if (saved_netns == -1)
+ return;
+
+ if (setns(saved_netns, CLONE_NEWNET)) {
+ perror("setns");
+ exit(1);
+ }
+
+ close(saved_netns);
+ saved_netns = -1;
+}
+
+static int netns_add(int argc, char **argv, bool create)
+{
+ /* 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.
+ *
+ * If create is true, a new namespace will be created,
+ * otherwise an existing one will be attached to the file.
+ *
+ * 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 users.
+ */
+ char netns_path[PATH_MAX], proc_path[PATH_MAX];
+ const char *name;
+ pid_t pid;
+ int fd;
+ int lock;
+ int made_netns_run_dir_mount = 0;
+
+ if (create) {
+ if (argc < 1) {
+ fprintf(stderr, "No netns name specified\n");
+ return -1;
+ }
+ } else {
+ if (argc < 2) {
+ fprintf(stderr, "No netns name and PID specified\n");
+ return -1;
+ }
+
+ if (get_s32(&pid, argv[1], 0) || !pid) {
+ fprintf(stderr, "Invalid PID: %s\n", argv[1]);
+ return -1;
+ }
+ }
+ name = argv[0];
+
+ snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
+
+ if (create_netns_dir())
+ return -1;
+
+ /* Make it possible for network namespace mounts to propagate between
+ * mount namespaces. This makes it likely that a unmounting a network
+ * namespace file in one namespace will unmount the network namespace
+ * file in all namespaces allowing the network namespace to be freed
+ * sooner.
+ * These setup steps need to happen only once, as if multiple ip processes
+ * try to attempt the same operation at the same time, the mountpoints will
+ * be recursively created multiple times, eventually causing the system
+ * to lock up. For example, this has been observed when multiple netns
+ * namespaces are created in parallel at boot. See:
+ * https://bugs.debian.org/949235
+ * Try to take an exclusive file lock on the top level directory to ensure
+ * this cannot happen, but proceed nonetheless if it cannot happen for any
+ * reason.
+ */
+ lock = open(NETNS_RUN_DIR, O_RDONLY|O_DIRECTORY, 0);
+ if (lock < 0) {
+ fprintf(stderr, "Cannot open netns runtime directory \"%s\": %s\n",
+ NETNS_RUN_DIR, strerror(errno));
+ return -1;
+ }
+ if (flock(lock, LOCK_EX) < 0) {
+ fprintf(stderr, "Warning: could not flock netns runtime directory \"%s\": %s\n",
+ NETNS_RUN_DIR, strerror(errno));
+ close(lock);
+ lock = -1;
+ }
+ while (mount("", NETNS_RUN_DIR, "none", MS_SHARED | MS_REC, NULL)) {
+ /* Fail unless we need to make the mount point */
+ if (errno != EINVAL || made_netns_run_dir_mount) {
+ fprintf(stderr, "mount --make-shared %s failed: %s\n",
+ NETNS_RUN_DIR, strerror(errno));
+ if (lock != -1) {
+ flock(lock, LOCK_UN);
+ close(lock);
+ }
+ return -1;
+ }
+
+ /* Upgrade NETNS_RUN_DIR to a mount point */
+ if (mount(NETNS_RUN_DIR, NETNS_RUN_DIR, "none", MS_BIND | MS_REC, NULL)) {
+ fprintf(stderr, "mount --bind %s %s failed: %s\n",
+ NETNS_RUN_DIR, NETNS_RUN_DIR, strerror(errno));
+ if (lock != -1) {
+ flock(lock, LOCK_UN);
+ close(lock);
+ }
+ return -1;
+ }
+ made_netns_run_dir_mount = 1;
+ }
+ if (lock != -1) {
+ flock(lock, LOCK_UN);
+ close(lock);
+ }
+
+ /* Create the filesystem state */
+ fd = open(netns_path, O_RDONLY|O_CREAT|O_EXCL, 0);
+ if (fd < 0) {
+ fprintf(stderr, "Cannot create namespace file \"%s\": %s\n",
+ netns_path, strerror(errno));
+ return -1;
+ }
+ close(fd);
+
+ if (create) {
+ netns_save();
+ if (unshare(CLONE_NEWNET) < 0) {
+ fprintf(stderr, "Failed to create a new network namespace \"%s\": %s\n",
+ name, strerror(errno));
+ goto out_delete;
+ }
+
+ strcpy(proc_path, "/proc/self/ns/net");
+ } else {
+ snprintf(proc_path, sizeof(proc_path), "/proc/%d/ns/net", pid);
+ }
+
+ /* Bind the netns last so I can watch for it */
+ if (mount(proc_path, netns_path, "none", MS_BIND, NULL) < 0) {
+ fprintf(stderr, "Bind %s -> %s failed: %s\n",
+ proc_path, netns_path, strerror(errno));
+ goto out_delete;
+ }
+ netns_restore();
+
+ return 0;
+out_delete:
+ if (create) {
+ netns_restore();
+ netns_delete(argc, argv);
+ } else if (unlink(netns_path) < 0) {
+ fprintf(stderr, "Cannot remove namespace file \"%s\": %s\n",
+ netns_path, strerror(errno));
+ }
+ return -1;
+}
+
+int set_netnsid_from_name(const char *name, int nsid)
+{
+ struct {
+ struct nlmsghdr n;
+ struct rtgenmsg g;
+ char buf[1024];
+ } req = {
+ .n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtgenmsg)),
+ .n.nlmsg_flags = NLM_F_REQUEST,
+ .n.nlmsg_type = RTM_NEWNSID,
+ .g.rtgen_family = AF_UNSPEC,
+ };
+ int fd, err = 0;
+
+ netns_nsid_socket_init();
+
+ fd = netns_get_fd(name);
+ if (fd < 0)
+ return fd;
+
+ addattr32(&req.n, 1024, NETNSA_FD, fd);
+ addattr32(&req.n, 1024, NETNSA_NSID, nsid);
+ if (rtnl_talk(&rth, &req.n, NULL) < 0)
+ err = -2;
+
+ close(fd);
+ return err;
+}
+
+static int netns_set(int argc, char **argv)
+{
+ char netns_path[PATH_MAX];
+ const char *name;
+ int netns, nsid;
+
+ if (argc < 1) {
+ fprintf(stderr, "No netns name specified\n");
+ return -1;
+ }
+ if (argc < 2) {
+ fprintf(stderr, "No nsid specified\n");
+ return -1;
+ }
+ name = argv[0];
+ /* If a negative nsid is specified the kernel will select the nsid. */
+ if (strcmp(argv[1], "auto") == 0)
+ nsid = -1;
+ else if (get_integer(&nsid, argv[1], 0))
+ invarg("Invalid \"netnsid\" value", argv[1]);
+ else if (nsid < 0)
+ invarg("\"netnsid\" value should be >= 0", argv[1]);
+
+ snprintf(netns_path, sizeof(netns_path), "%s/%s", NETNS_RUN_DIR, name);
+ netns = open(netns_path, O_RDONLY | O_CLOEXEC);
+ if (netns < 0) {
+ fprintf(stderr, "Cannot open network namespace \"%s\": %s\n",
+ name, strerror(errno));
+ return -1;
+ }
+
+ return set_netnsid_from_name(name, nsid);
+}
+
+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 (create_netns_dir())
+ 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;
+}
+
+static int invalid_name(const char *name)
+{
+ return !*name || strlen(name) > NAME_MAX ||
+ strchr(name, '/') || !strcmp(name, ".") || !strcmp(name, "..");
+}
+
+int do_netns(int argc, char **argv)
+{
+ netns_nsid_socket_init();
+
+ if (argc < 1) {
+ netns_map_init();
+ return netns_list(0, NULL);
+ }
+
+ if (!do_all && argc > 1 && invalid_name(argv[1])) {
+ fprintf(stderr, "Invalid netns name \"%s\"\n", argv[1]);
+ exit(-1);
+ }
+
+ if ((matches(*argv, "list") == 0) || (matches(*argv, "show") == 0) ||
+ (matches(*argv, "lst") == 0)) {
+ netns_map_init();
+ return netns_list(argc-1, argv+1);
+ }
+
+ if ((matches(*argv, "list-id") == 0)) {
+ netns_map_init();
+ return netns_list_id(argc-1, argv+1);
+ }
+
+ if (matches(*argv, "help") == 0)
+ return usage();
+
+ if (matches(*argv, "add") == 0)
+ return netns_add(argc-1, argv+1, true);
+
+ if (matches(*argv, "set") == 0)
+ return netns_set(argc-1, argv+1);
+
+ if (matches(*argv, "delete") == 0)
+ return netns_delete(argc-1, argv+1);
+
+ if (matches(*argv, "identify") == 0)
+ return netns_identify(argc-1, argv+1);
+
+ if (matches(*argv, "pids") == 0)
+ return netns_pids(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);
+
+ if (matches(*argv, "attach") == 0)
+ return netns_add(argc-1, argv+1, false);
+
+ fprintf(stderr, "Command \"%s\" is unknown, try \"ip netns help\".\n", *argv);
+ exit(-1);
+}
generated by cgit v1.2.3 (git 2.39.1) at 2024-06-26 04:34:51 +0000