RTN_UNSPEC	0
RTN_UNICAST	1
RTN_LOCAL	2
RTN_BROADCAST	3
RTN_ANYCAST	4
RTN_MULTICAST	5
RTN_BLACKHOLE	6
RTN_UNREACHABLE	7
RTN_PROHIBIT	8
RTN_THROW	9
RTN_NAT		10
RTN_XRESOLVE	11