iplink: implement setting of master devic

ip/iplink.c

@@ -71,6 +71,8 @@ void iplink_usage(void)
 	fprintf(stderr, "	                  [ vf NUM [ mac LLADDR ]\n");
 	fprintf(stderr, "				   [ vlan VLANID [ qos VLAN-QOS ] ]\n");
 	fprintf(stderr, "				   [ rate TXRATE ] ] \n");
+	fprintf(stderr, "			  [ master DEVICE ]\n");
+	fprintf(stderr, "			  [ nomaster ]\n");
 	fprintf(stderr, "       ip link show [ DEVICE | group GROUP ]\n");
 
 	if (iplink_have_newlink()) {
@@ -362,6 +364,20 @@ int iplink_parse(int argc, char **argv, struct iplink_req *req,
 			if (len < 0)
 				return -1;
 			addattr_nest_end(&req->n, vflist);
+#ifdef IFLA_MASTER
+		} else if (matches(*argv, "master") == 0) {
+			int ifindex;
+			NEXT_ARG();
+			ifindex = ll_name_to_index(*argv);
+			if (!ifindex)
+				invarg("Device does not exist\n", *argv);
+			addattr_l(&req->n, sizeof(*req), IFLA_MASTER,
+				  &ifindex, 4);
+		} else if (matches(*argv, "nomaster") == 0) {
+			int ifindex = 0;
+			addattr_l(&req->n, sizeof(*req), IFLA_MASTER,
+				  &ifindex, 4);
+#endif
 #ifdef IFF_DYNAMIC
 		} else if (matches(*argv, "dynamic") == 0) {
 			NEXT_ARG();

man/man8/ip.8

@@ -97,7 +97,12 @@ ip \- show / manipulate routing, devices, policy routing and tunnels
 .B qos
 .IR VLAN-QOS " ] ] ["
 .B rate
-.IR TXRATE " ]"
+.IR TXRATE " ] |"
+.br
+.B master
+.IR DEVICE
+.br
+.B nomaster
 
 .ti -8
 .B ip link show
@@ -1055,6 +1060,14 @@ Setting this parameter to 0 disables rate limiting. The
 parameter must be specified.
 .in -8
 
+.TP
+.BI master " DEVICE"
+set master device of the device (enslave device).
+
+.TP
+.BI nomaster
+unset master device of the device (release device).
+
 .PP
 .B Warning:
 If multiple parameter changes are requested,