[PATCH iproute2] iplink: enable to specify newifindex when changing netns

@@ -95,7 +95,7 @@ void iplink_usage(void)
 		"		[ address LLADDR ]\n"
 		"		[ broadcast LLADDR ]\n"
 		"		[ mtu MTU ]\n"
-		"		[ netns { PID | NAME } ]\n"
+		"		[ netns { PID | NAME } [ newindex IXD ] ]\n"
 		"		[ link-netns NAME | link-netnsid ID ]\n"
 		"		[ alias NAME ]\n"
 		"		[ vf NUM [ mac LLADDR ]\n"

@@ -590,6 +590,7 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 	int numtxqueues = -1;
 	int numrxqueues = -1;
 	int link_netnsid = -1;
+	int newindex = 0;
 	int index = 0;
 	int group = -1;
 	int addr_len = 0;

@@ -683,6 +684,15 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 					  IFLA_NET_NS_PID, &netns, 4);
 			else
 				invarg("Invalid \"netns\" value\n", *argv);
+		} else if (strcmp(*argv, "newindex") == 0) {
+			NEXT_ARG();
+			if (newindex)
+				duparg("newindex", *argv);
+			newindex = atoi(*argv);
+			if (newindex <= 0)
+				invarg("Invalid \"newindex\" value", *argv);
+			addattr32(&req->n, sizeof(*req), IFLA_NEW_IFINDEX,
+				  newindex);
 		} else if (strcmp(*argv, "multicast") == 0) {
 			NEXT_ARG();
 			req->i.ifi_change |= IFF_MULTICAST;

@@ -578,6 +578,7 @@ static int iplink_parse_vf(int vf, int *argcp, char ***argvp,
 
 int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 {
+	bool move_netns = false;
 	char *name = NULL;
 	char *dev = NULL;
 	char *link = NULL;

@@ -683,6 +684,7 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 					  IFLA_NET_NS_PID, &netns, 4);
 			else
 				invarg("Invalid \"netns\" value\n", *argv);
+			move_netns = true;
 		} else if (strcmp(*argv, "multicast") == 0) {
 			NEXT_ARG();
 			req->i.ifi_change |= IFF_MULTICAST;

@@ -980,9 +982,11 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 		}
 	}
 
-	if (!(req->n.nlmsg_flags & NLM_F_CREATE) && index) {
+	if (index &&
+	    (!(req->n.nlmsg_flags & NLM_F_CREATE) &&
+	     !move_netns)) {
 		fprintf(stderr,
-			"index can be used only when creating devices.\n");
+			"index can be used only when creating devices or when moving device to another netns.\n");
 		exit(-1);
 	}
 

@@ -1019,6 +1023,9 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req, char **type)
 		/* Not renaming to the same name */
 		if (name == dev)
 			name = NULL;
+
+		if (index)
+			addattr32(&req->n, sizeof(*req), IFLA_NEW_IFINDEX, index);
 	} else {
 		if (name != dev) {
 			fprintf(stderr,