netns: allow to dump and monitor nsid
Two commands are added:
- ip netns list-id
- ip monitor nsid
A cache is also added to remember the association between the iproute2 netns
name (from /var/run/netns/) and the nsid.
To avoid interfering with the rth socket, a new rtnl socket (rtnsh) is used to
get nsid (we may send rtnl request during listing on rth).
Example:
$ ip netns list-id
nsid 0 (iproute2 netns name: foo)
$ ip monitor nsid
Deleted nsid 0 (iproute2 netns name: foo)
nsid 16 (iproute2 netns name: bar)
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
diff --git a/ip/ipnetns.c b/ip/ipnetns.c
index 24df167..438d59b 100644
--- a/ip/ipnetns.c
+++ b/ip/ipnetns.c
@@ -14,10 +14,12 @@
#include <errno.h>
#include <unistd.h>
#include <ctype.h>
+#include <linux/limits.h>
#include <linux/net_namespace.h>
#include "utils.h"
+#include "hlist.h"
#include "ip_common.h"
#include "namespace.h"
@@ -31,9 +33,13 @@
fprintf(stderr, " ip netns pids NAME\n");
fprintf(stderr, " ip [-all] netns exec [NAME] cmd ...\n");
fprintf(stderr, " ip netns monitor\n");
+ fprintf(stderr, " ip netns list-id\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 ipnetns_accept_msg(const struct sockaddr_nl *who,
@@ -106,7 +112,7 @@
return fd;
addattr32(&req.n, 1024, NETNSA_FD, fd);
- if (rtnl_talk(&rth, &req.n, 0, 0, &answer.n) < 0) {
+ if (rtnl_talk(&rtnsh, &req.n, 0, 0, &answer.n) < 0) {
close(fd);
return -2;
}
@@ -129,6 +135,196 @@
return -1;
}
+struct nsid_cache {
+ struct hlist_node nsid_hash;
+ struct hlist_node name_hash;
+ int nsid;
+ char name[NAME_MAX];
+};
+
+#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)
+{
+ uint32_t h = NSID_HASH_NSID(nsid);
+ struct hlist_node *n;
+
+ 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;
+}
+
+static int netns_map_add(int nsid, char *name)
+{
+ struct nsid_cache *c;
+ uint32_t h;
+
+ if (netns_map_get_by_nsid(nsid) != NULL)
+ return -EEXIST;
+
+ c = malloc(sizeof(*c));
+ 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_map_init(void)
+{
+ static int initialized;
+ struct dirent *entry;
+ DIR *dir;
+ int nsid;
+
+ if (initialized || !ipnetns_have_nsid())
+ return;
+
+ if (rtnl_open(&rtnsh, 0) < 0) {
+ fprintf(stderr, "Cannot open rtnetlink\n");
+ exit(1);
+ }
+
+ 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;
+
+ 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 (nsid == id) {
+ strcpy(name, entry->d_name);
+ closedir(dir);
+ return 0;
+ }
+ }
+ closedir(dir);
+ return -ENOENT;
+}
+
+int print_nsid(const struct sockaddr_nl *who, 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;
+
+ 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;
+ }
+
+ if (n->nlmsg_type == RTM_DELNSID)
+ fprintf(fp, "Deleted ");
+
+ nsid = rta_getattr_u32(tb[NETNSA_NSID]);
+ fprintf(fp, "nsid %u ", nsid);
+
+ c = netns_map_get_by_nsid(nsid);
+ if (c != NULL) {
+ fprintf(fp, "(iproute2 netns name: %s)", c->name);
+ netns_map_del(c);
+ }
+
+ /* During 'ip monitor nsid', no chance to have new nsid in cache. */
+ if (c == NULL && n->nlmsg_type == RTM_NEWNSID)
+ if (netns_get_name(nsid, name) == 0) {
+ fprintf(fp, "(iproute2 netns name: %s)", name);
+ netns_map_add(nsid, name);
+ }
+
+ fprintf(fp, "\n");
+ fflush(fp);
+ return 0;
+}
+
+static int netns_list_id(int argc, char **argv)
+{
+ if (!ipnetns_have_nsid()) {
+ fprintf(stderr,
+ "RTM_GETNSID is not supported by the kernel.\n");
+ return -ENOTSUP;
+ }
+
+ if (rtnl_wilddump_request(&rth, AF_UNSPEC, RTM_GETNSID) < 0) {
+ perror("Cannot send dump request");
+ exit(1);
+ }
+ if (rtnl_dump_filter(&rth, print_nsid, stdout) < 0) {
+ fprintf(stderr, "Dump terminated\n");
+ exit(1);
+ }
+ return 0;
+}
+
static int netns_list(int argc, char **argv)
{
struct dirent *entry;
@@ -577,6 +773,8 @@
int do_netns(int argc, char **argv)
{
+ netns_map_init();
+
if (argc < 1)
return netns_list(0, NULL);
@@ -584,6 +782,9 @@
(matches(*argv, "lst") == 0))
return netns_list(argc-1, argv+1);
+ if ((matches(*argv, "list-id") == 0))
+ return netns_list_id(argc-1, argv+1);
+
if (matches(*argv, "help") == 0)
return usage();