IP4_ADDR_3
SYS(fail, "ip -n %s a add %s/24 dev veth3", ns2, IP4_ADDR_3);
SYS(fail, "ip route add %s/32 dev veth4", IP4_ADDR_3);
SYS(fail, "ip route add %s/32 dev veth4 via %s", IP4_ADDR_1, IP4_ADDR_3);
SYS(fail, "ip route add %s/32 dev veth4 via %s", IP4_ADDR_2, IP4_ADDR_3);