STREAMS Framework – Kernel Level

Because the STREAMS subsystem of UNIX® provides a framework on which communications services can be built, it is often called the STREAMS framework. This framework consists of the stream head and a series of utilities (put, putnext), kernel structures (mblk, dblk), and linkages (queues) that facilitate the interconnections between modules, drivers, and basic system calls. This chapter describes the STREAMS components from the kernel developer's perspective.

• Overview of Streams in Kernel Space

• Stream Head

• Kernel-Level Messages

• Message Queues

• Entry Points

• Flow Control in Service Procedures