commit a721ebaafd6852e86b636e2595e36f635c2b3cae

Author: Nicolas Dichtel <nicolas.dichtel@6wind.com>

Date:   Wed Apr 15 14:23:22 2015 +0200

    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/include/ll_map.h b/include/ll_map.h

index f1dda39..a9d9cb3 100644

--- a/include/ll_map.h

+++ b/include/ll_map.h

@@ -10,5 +10,6 @@ extern const char *ll_index_to_name(unsigned idx);

 extern const char *ll_idx_n2a(unsigned idx, char *buf);

 extern int ll_index_to_type(unsigned idx);

 extern unsigned ll_index_to_flags(unsigned idx);

+extern unsigned namehash(const char *str);

 #endif /* __LL_MAP_H__ */

diff --git a/ip/ip_common.h b/ip/ip_common.h

index f9b4734..85529f0 100644

--- a/ip/ip_common.h

+++ b/ip/ip_common.h

@@ -30,6 +30,9 @@ extern int print_rule(const struct sockaddr_nl *who,

 		      struct nlmsghdr *n, void *arg);

 extern int print_netconf(const struct sockaddr_nl *who,

 			 struct nlmsghdr *n, void *arg);

+extern void netns_map_init(void);

+extern int print_nsid(const struct sockaddr_nl *who,

+		      struct nlmsghdr *n, void *arg);

 extern int do_ipaddr(int argc, char **argv);

 extern int do_ipaddrlabel(int argc, char **argv);

 extern int do_iproute(int argc, char **argv);

diff --git a/ip/ipmonitor.c b/ip/ipmonitor.c

index 86c473e..148cf1e 100644

--- a/ip/ipmonitor.c

+++ b/ip/ipmonitor.c

@@ -31,7 +31,7 @@ static void usage(void)

 {

 	fprintf(stderr, "Usage: ip monitor [ all | LISTofOBJECTS ] [ FILE ]\n");

 	fprintf(stderr, "LISTofOBJECTS := link | address | route | mroute | prefix |\n");

-	fprintf(stderr, "                 neigh | netconf\n");

+	fprintf(stderr, "                 neigh | netconf | nsid\n");

 	fprintf(stderr, "FILE := file FILENAME\n");

 	exit(-1);

 }

@@ -127,6 +127,12 @@ static int accept_msg(const struct sockaddr_nl *who,

 	    n->nlmsg_type == RTM_NEWTFILTER ||

 	    n->nlmsg_type == RTM_DELTFILTER)

 		return 0;

+	if (n->nlmsg_type == RTM_NEWNSID || n->nlmsg_type == RTM_DELNSID) {

+		if (prefix_banner)

+			fprintf(fp, "[NSID]");

+		print_nsid(who, n, arg);

+		return 0;

+	}

 	if (n->nlmsg_type != NLMSG_ERROR && n->nlmsg_type != NLMSG_NOOP &&

 	    n->nlmsg_type != NLMSG_DONE) {

 		fprintf(fp, "Unknown message: %08x %08x %08x\n",

@@ -146,6 +152,9 @@ int do_ipmonitor(int argc, char **argv)

 	int lprefix=0;

 	int lneigh=0;

 	int lnetconf=0;

+	int lnsid=0;

+

+	groups |= nl_mgrp(RTNLGRP_NSID);

 	rtnl_close(&rth);

 	ipaddr_reset_filter(1);

@@ -178,6 +187,9 @@ int do_ipmonitor(int argc, char **argv)

 		} else if (matches(*argv, "netconf") == 0) {

 			lnetconf = 1;

 			groups = 0;

+		} else if (matches(*argv, "nsid") == 0) {

+			lnsid = 1;

+			groups = 0;

 		} else if (strcmp(*argv, "all") == 0) {

 			groups = ~RTMGRP_TC;

 			prefix_banner=1;

@@ -223,6 +235,9 @@ int do_ipmonitor(int argc, char **argv)

 		if (!preferred_family || preferred_family == AF_INET6)

 			groups |= nl_mgrp(RTNLGRP_IPV6_NETCONF);

 	}

+	if (lnsid) {

+		groups |= nl_mgrp(RTNLGRP_NSID);

+	}

 	if (file) {

 		FILE *fp;

 		fp = fopen(file, "r");

@@ -236,6 +251,7 @@ int do_ipmonitor(int argc, char **argv)

 	if (rtnl_open(&rth, groups) < 0)

 		exit(1);

 	ll_init_map(&rth);

+	netns_map_init();

 	if (rtnl_listen(&rth, accept_msg, stdout) < 0)

 		exit(2);

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 @@ static int usage(void)

 	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 @@ static int get_netnsid_from_name(const char *name)

 		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 @@ static int get_netnsid_from_name(const char *name)

 	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 @@ static int netns_monitor(int argc, char **argv)

 int do_netns(int argc, char **argv)

 {

+	netns_map_init();

+

 	if (argc < 1)

 		return netns_list(0, NULL);

@@ -584,6 +782,9 @@ int do_netns(int argc, char **argv)

 	    (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();

diff --git a/lib/ll_map.c b/lib/ll_map.c

index fd7db55..a57a150 100644

--- a/lib/ll_map.c

+++ b/lib/ll_map.c

@@ -52,7 +52,7 @@ static struct ll_cache *ll_get_by_index(unsigned index)

 	return NULL;

 }

-static unsigned namehash(const char *str)

+unsigned namehash(const char *str)

 {

 	unsigned hash = 5381;

diff --git a/man/man8/ip-monitor.8 b/man/man8/ip-monitor.8

index b6e8d1d..a710b34 100644

--- a/man/man8/ip-monitor.8

+++ b/man/man8/ip-monitor.8

@@ -32,7 +32,7 @@ command is the first in the command line and then the object list follows:

 is the list of object types that we want to monitor.

 It may contain

 .BR link ", " address ", " route ", " mroute ", " prefix ", "

-.BR neigh " and " netconf "."

+.BR neigh ", " netconf " and " nsid "."

 If no

 .B file

 argument is given,

diff --git a/man/man8/ip-netns.8 b/man/man8/ip-netns.8

index 80a4ad1..c9b0fbc 100644

--- a/man/man8/ip-netns.8

+++ b/man/man8/ip-netns.8

@@ -42,6 +42,9 @@ ip-netns \- process network namespace management

 .ti -8

 .BR "ip netns monitor"

+.ti -8

+.BR "ip netns list-id"

+

 .SH DESCRIPTION

 A network namespace is logically another copy of the network stack,

 with its own routes, firewall rules, and network devices.

@@ -178,6 +181,13 @@ executing.

 This command watches network namespace name addition and deletion events

 and prints a line for each event it sees.

+.TP

+.B ip netns list-id - list network namespace ids (nsid)

+.sp

+Network namespace ids are used to identify a peer network namespace. This

+command displays nsid of the current network namespace and provides the

+corresponding iproute2 netns name (from /var/run/netns) if any.

+

 .SH EXAMPLES

 .PP

 ip netns list