The STREAMS Administrative Driver (SAD) provides an interface for applications to perform administrative operations on STREAMS modules and drivers. The interface is provided through ioctl commands. For more information see, the sad(4D) and ioctl(2) man pages.
You can use the autopush utility to configure a list of modules to be automatically pushed on a stream when a driver is first opened. For more information, see Autopush Facility and the autopush(8) man page.