IP4_ADDR_6
SYS(fail, "ip -n %s a add %s/24 dev veth6", ns2, IP4_ADDR_6);
SYS(fail, "ip route add %s/32 dev veth5 %s", IP4_ADDR_6, vrf);
SYS(fail, "ip route add %s/32 dev veth5 via %s %s", IP4_ADDR_7, IP4_ADDR_6, vrf);
SYS(fail, "ip route add %s/32 dev veth5 via %s %s", IP4_ADDR_8, IP4_ADDR_6, vrf);
SYS(fail, "ip route add %s/32 dev veth8 via %s", IP4_ADDR_6, IP4_ADDR_7);
ns1, IP4_ADDR_GRE, IP4_ADDR_6, vrf);