Technical data

tirdwr(7M) STREAMS Modules SunOS 5.5
NAME tirdwr − Transport Interface read/write interface STREAMS module
SYNOPSIS int ioctl( fd, I_PUSH, "tirdwr");
DESCRIPTION tirdwr is a STREAMS module that provides an alternate interface to a transport provider
which supports the Transport Interface (TI) functions of the Network Services library (see
Section 3N). This alternate interface allows a user to communicate with the transport
protocol provider using the read(2) and write(2) system calls. The putmsg(2) and
getmsg(2) system calls may also be used. However, putmsg and getmsg can only
transfer data messages between user and stream; control portions are disallowed.
The tirdwr module must only be pushed (see I_PUSH in streamio(7I)) onto a stream ter-
minated by a transport protocol provider which supports the TI. After the tirdwr module
has been pushed onto a stream, none of the Transport Interface functions can be used.
Subsequent calls to TI functions cause an error on the stream. Once the error is detected,
subsequent system calls on the stream return an error with errno set to EPROTO.
The following are the actions taken by the tirdwr module when pushed on the stream,
popped (see I_POP in streamio(7I)) off the stream, or when data passes through it.
push When the module is pushed onto a stream, it checks any existing data des-
tined for the user to ensure that only regular data messages are present. It
ignores any messages on the stream that relate to process management, such
as messages that generate signals to the user processes associated with the
stream. If any other messages are present, the I_PUSH will return an error
with errno set to EPROTO.
write The module takes the following actions on data that originated from a write
system call:
All messages with the exception of messages that contain control por-
tions (see the putmsg and getmsg system calls) are transparently
passed onto the module’s downstream neighbor.
Any zero lengthdata messages are freed by the module and they will
not be passed onto the module’s downstream neighbor.
Any messages with control portions generate an error, and any
further system calls associated with the stream fails with errno set to
EPROTO.
read The module takes the following actions on data that originated from the tran-
sport protocol provider:
All messages with the exception of those that contain control portions
(see the putmsg and getmsg system calls) are transparently passed
onto the module’s upstream neighbor.
7M-374 modified 3 Jul 1990