VETH0
SYS(fail, "ip link add " VETH0 " netns " NS0 " type veth peer name " VETH1 " netns " NS1);
SYS(fail, "ip -6 -net " NS0 " addr add " VETH0_ADDR6 "/64 dev " VETH0 " nodad");
SYS(fail, "ip -net " NS0 " addr add " VETH0_ADDR "/24 dev " VETH0);
SYS(fail, "ip -net " NS0 " link set dev " VETH0 " up");