The origin of this prefix. manual(2) indicates a prefix
that was manually configured. wellknown(3) indicates a
well-known prefix, e.g. 169.254/16 for IPv4
autoconfiguration or fe80::/10 for IPv6 link-local
addresses. dhcp(4) indicates a prefix that was assigned
by a DHCP server. routeradv(5) indicates a prefix
learned from a router advertisement.