ipmonitor: allows to monitor in several netns

With this patch, it's now possible to listen in all netns that have an nsid
assigned into the netns where the socket is opened.
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>

include/libnetlink.h

@@ -20,6 +20,8 @@ struct rtnl_handle
 	__u32			dump;
 	int			proto;
 	FILE		       *dump_fp;
+#define RTNL_HANDLE_F_LISTEN_ALL_NSID		0x01
+	int			flags;
 };
 
 extern int rcvbuf;
@@ -42,6 +44,7 @@ extern int rtnl_dump_request(struct rtnl_handle *rth, int type, void *req,
 	__attribute__((warn_unused_result));
 
 struct rtnl_ctrl_data {
+	int	nsid;
 };
 
 typedef int (*rtnl_filter_t)(const struct sockaddr_nl *,
@@ -125,6 +128,7 @@ static inline const char *rta_getattr_str(const struct rtattr *rta)
 	return (const char *)RTA_DATA(rta);
 }
 
+extern int rtnl_listen_all_nsid(struct rtnl_handle *);
 extern int rtnl_listen(struct rtnl_handle *, rtnl_listen_filter_t handler,
 		       void *jarg);
 extern int rtnl_from_file(FILE *, rtnl_listen_filter_t handler,

ip/ipmonitor.c

@@ -26,22 +26,30 @@
 
 static void usage(void) __attribute__((noreturn));
 int prefix_banner;
+int listen_all_nsid;
 
 static void usage(void)
 {
-	fprintf(stderr, "Usage: ip monitor [ all | LISTofOBJECTS ] [ FILE ]"
-			"[ label ] [dev DEVICE]\n");
+	fprintf(stderr, "Usage: ip monitor [ all | LISTofOBJECTS ] [ FILE ] "
+			"[ label ] [all-nsid] [dev DEVICE]\n");
 	fprintf(stderr, "LISTofOBJECTS := link | address | route | mroute | prefix |\n");
 	fprintf(stderr, "                 neigh | netconf | rule | nsid\n");
 	fprintf(stderr, "FILE := file FILENAME\n");
 	exit(-1);
 }
 
-static void print_headers(FILE *fp, char *label)
+static void print_headers(FILE *fp, char *label, struct rtnl_ctrl_data *ctrl)
 {
 	if (timestamp)
 		print_timestamp(fp);
 
+	if (listen_all_nsid) {
+		if (ctrl == NULL || ctrl->nsid < 0)
+			fprintf(fp, "[nsid current]");
+		else
+			fprintf(fp, "[nsid %d]", ctrl->nsid);
+	}
+
 	if (prefix_banner)
 		fprintf(fp, "%s", label);
 }
@@ -66,11 +74,11 @@ static int accept_msg(const struct sockaddr_nl *who,
 
 		if (r->rtm_family == RTNL_FAMILY_IPMR ||
 		    r->rtm_family == RTNL_FAMILY_IP6MR) {
-			print_headers(fp, "[MROUTE]");
+			print_headers(fp, "[MROUTE]", ctrl);
 			print_mroute(who, n, arg);
 			return 0;
 		} else {
-			print_headers(fp, "[ROUTE]");
+			print_headers(fp, "[ROUTE]", ctrl);
 			print_route(who, n, arg);
 			return 0;
 		}
@@ -78,17 +86,17 @@ static int accept_msg(const struct sockaddr_nl *who,
 
 	if (n->nlmsg_type == RTM_NEWLINK || n->nlmsg_type == RTM_DELLINK) {
 		ll_remember_index(who, n, NULL);
-		print_headers(fp, "[LINK]");
+		print_headers(fp, "[LINK]", ctrl);
 		print_linkinfo(who, n, arg);
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWADDR || n->nlmsg_type == RTM_DELADDR) {
-		print_headers(fp, "[ADDR]");
+		print_headers(fp, "[ADDR]", ctrl);
 		print_addrinfo(who, n, arg);
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWADDRLABEL || n->nlmsg_type == RTM_DELADDRLABEL) {
-		print_headers(fp, "[ADDRLABEL]");
+		print_headers(fp, "[ADDRLABEL]", ctrl);
 		print_addrlabel(who, n, arg);
 		return 0;
 	}
@@ -101,22 +109,22 @@ static int accept_msg(const struct sockaddr_nl *who,
 				return 0;
 		}
 
-		print_headers(fp, "[NEIGH]");
+		print_headers(fp, "[NEIGH]", ctrl);
 		print_neigh(who, n, arg);
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWPREFIX) {
-		print_headers(fp, "[PREFIX]");
+		print_headers(fp, "[PREFIX]", ctrl);
 		print_prefix(who, n, arg);
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWRULE || n->nlmsg_type == RTM_DELRULE) {
-		print_headers(fp, "[RULE]");
+		print_headers(fp, "[RULE]", ctrl);
 		print_rule(who, n, arg);
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWNETCONF) {
-		print_headers(fp, "[NETCONF]");
+		print_headers(fp, "[NETCONF]", ctrl);
 		print_netconf(who, ctrl, n, arg);
 		return 0;
 	}
@@ -125,7 +133,7 @@ static int accept_msg(const struct sockaddr_nl *who,
 		return 0;
 	}
 	if (n->nlmsg_type == RTM_NEWNSID || n->nlmsg_type == RTM_DELNSID) {
-		print_headers(fp, "[NSID]");
+		print_headers(fp, "[NSID]", ctrl);
 		print_nsid(who, n, arg);
 		return 0;
 	}
@@ -178,6 +186,8 @@ int do_ipmonitor(int argc, char **argv)
 			file = *argv;
 		} else if (matches(*argv, "label") == 0) {
 			prefix_banner = 1;
+		} else if (matches(*argv, "all-nsid") == 0) {
+			listen_all_nsid = 1;
 		} else if (matches(*argv, "link") == 0) {
 			llink=1;
 			groups = 0;
@@ -284,6 +294,9 @@ int do_ipmonitor(int argc, char **argv)
 
 	if (rtnl_open(&rth, groups) < 0)
 		exit(1);
+	if (listen_all_nsid && rtnl_listen_all_nsid(&rth) < 0)
+		exit(1);
+
 	ll_init_map(&rth);
 	netns_map_init();
 

lib/libnetlink.c

@@ -25,6 +25,10 @@
 
 #include "libnetlink.h"
 
+#ifndef SOL_NETLINK
+#define SOL_NETLINK 270
+#endif
+
 int rcvbuf = 1024 * 1024;
 
 void rtnl_close(struct rtnl_handle *rth)
@@ -418,6 +422,19 @@ int rtnl_talk(struct rtnl_handle *rtnl, struct nlmsghdr *n, pid_t peer,
 	}
 }
 
+int rtnl_listen_all_nsid(struct rtnl_handle *rth)
+{
+	unsigned int on = 1;
+
+	if (setsockopt(rth->fd, SOL_NETLINK, NETLINK_LISTEN_ALL_NSID, &on,
+		       sizeof(on)) < 0) {
+		perror("NETLINK_LISTEN_ALL_NSID");
+		return -1;
+	}
+	rth->flags |= RTNL_HANDLE_F_LISTEN_ALL_NSID;
+	return 0;
+}
+
 int rtnl_listen(struct rtnl_handle *rtnl,
 		rtnl_listen_filter_t handler,
 		void *jarg)
@@ -433,6 +450,12 @@ int rtnl_listen(struct rtnl_handle *rtnl,
 		.msg_iovlen = 1,
 	};
 	char   buf[16384];
+	char   cmsgbuf[BUFSIZ];
+
+	if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
+		msg.msg_control = &cmsgbuf;
+		msg.msg_controllen = sizeof(cmsgbuf);
+	}
 
 	memset(&nladdr, 0, sizeof(nladdr));
 	nladdr.nl_family = AF_NETLINK;
@@ -441,6 +464,9 @@ int rtnl_listen(struct rtnl_handle *rtnl,
 
 	iov.iov_base = buf;
 	while (1) {
+		struct rtnl_ctrl_data ctrl;
+		struct cmsghdr *cmsg;
+
 		iov.iov_len = sizeof(buf);
 		status = recvmsg(rtnl->fd, &msg, 0);
 
@@ -461,6 +487,21 @@ int rtnl_listen(struct rtnl_handle *rtnl,
 			fprintf(stderr, "Sender address length == %d\n", msg.msg_namelen);
 			exit(1);
 		}
+
+		if (rtnl->flags & RTNL_HANDLE_F_LISTEN_ALL_NSID) {
+			memset(&ctrl, 0, sizeof(ctrl));
+			ctrl.nsid = -1;
+			for (cmsg = CMSG_FIRSTHDR(&msg); cmsg;
+			     cmsg = CMSG_NXTHDR(&msg, cmsg))
+				if (cmsg->cmsg_level == SOL_NETLINK &&
+				    cmsg->cmsg_type == NETLINK_LISTEN_ALL_NSID &&
+				    cmsg->cmsg_len == CMSG_LEN(sizeof(int))) {
+					int *data = (int *)CMSG_DATA(cmsg);
+
+					ctrl.nsid = *data;
+				}
+		}
+
 		for (h = (struct nlmsghdr*)buf; status >= sizeof(*h); ) {
 			int err;
 			int len = h->nlmsg_len;
@@ -475,7 +516,7 @@ int rtnl_listen(struct rtnl_handle *rtnl,
 				exit(1);
 			}
 
-			err = handler(&nladdr, NULL, h, jarg);
+			err = handler(&nladdr, &ctrl, h, jarg);
 			if (err < 0)
 				return err;
 

man/man8/ip-monitor.8

@@ -14,6 +14,8 @@ ip-monitor, rtmon \- state monitoring
 ] [
 .BI label
 ] [
+.BI all-nsid
+] [
 .BI dev " DEVICE "
 ]
 .sp
@@ -46,6 +48,8 @@ command is the first in the command line and then the object list follows:
 ] [
 .BI label
 ] [
+.BI all-nsid
+] [
 .BI dev " DEVICE "
 ]
 
@@ -74,6 +78,19 @@ show the family of the message. For example:
 .in -2
 .sp
 
+.P
+If the
+.BI all-nsid
+option is set, the program listens to all network namespaces that have a
+nsid assigned into the network namespace were the program is running.
+A prefix is displayed to show the network namespace where the message
+originates. Example:
+.sp
+.in +2
+[nsid 0]10.16.0.112 dev eth0 lladdr 00:04:23:df:2f:d0 REACHABLE
+.in -2
+.sp
+
 .P
 If the
 .BI file