openvswitch: Honor dp_ifindex, when specified, for vport lookup by name.

When OVS_VPORT_ATTR_NAME is specified and dp_ifindex is nonzero, the
logical behavior would be for the vport name lookup scope to be limited
to the specified datapath, but in fact the dp_ifindex value was ignored.
This commit causes the search scope to be honored.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>

net/openvswitch/datapath.c

@@ -1521,6 +1521,9 @@ static struct vport *lookup_vport(struct ovs_header *ovs_header,
 		vport = ovs_vport_locate(nla_data(a[OVS_VPORT_ATTR_NAME]));
 		if (!vport)
 			return ERR_PTR(-ENODEV);
+		if (ovs_header->dp_ifindex &&
+		    ovs_header->dp_ifindex != get_dpifindex(vport->dp))
+			return ERR_PTR(-ENODEV);
 		return vport;
 	} else if (a[OVS_VPORT_ATTR_PORT_NO]) {
 		u32 port_no = nla_get_u32(a[OVS_VPORT_ATTR_PORT_NO]);