1tirdwr(7M) STREAMS Modules tirdwr(7M)
2
6 tirdwr - Transport Interface read/write interface STREAMS module
7
9 int ioctl( fd, I_PUSH, "tirdwr");
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13 tirdwr is a STREAMS module that provides an alternate interface to a
14 transport provider which supports the Transport Interface ("TI") func‐
15 tions of the Network Services library (see Section 3N). This alternate
16 interface allows a user to communicate with the transport protocol
17 provider using the read(2) and write(2) system calls. The putmsg(2)
18 and getmsg(2) system calls may also be used. However, putmsg and
19 getmsg can only transfer data messages between user and stream; con‐
20 trol portions are disallowed.
21 The tirdwr module must only be pushed (see I_PUSH in streamio(7I))
24 onto a stream terminated by a transport protocol provider which sup‐
25 ports the TI. After the tirdwr module has been pushed onto a stream,
26 none of the TI functions can be used. Subsequent calls to TI functions
27 cause an error on the stream. Once the error is detected, subsequent
28 system calls on the stream return an error with errno set to EPROTO.
29 The following are the actions taken by the tirdwr module when pushed on
32 the stream, popped (see I_POP in streamio(7I)) off the stream, or
33 when data passes through it.
34 push When the module is pushed onto a stream, it checks any exist‐
36 ing data destined for the user to ensure that only regular
37 data messages are present. It ignores any messages on the
38 stream that relate to process management, such as messages
39 that generate signals to the user processes associated with
40 the stream. If any other messages are present, the I_PUSH will
41 return an error with errno set to EPROTO.
42 write The module takes the following actions on data that originated
45 from a write system call:
46 o All messages with the exception of messages that
48 contain control portions (see the putmsg and getmsg
49 system calls) are transparently passed onto the
50 module's downstream neighbor.
51 o Any zero length data messages are freed by the mod‐
53 ule and they will not be passed onto the module's
54 downstream neighbor.
55 o Any messages with control portions generate an
57 error, and any further system calls associated with
58 the stream fails with errno set to EPROTO.
59 read The module takes the following actions on data that originated
62 from the transport protocol provider.
63 All messages with the exception of those that contain control
65 portions (see the putmsg and getmsg system calls) are trans‐
66 parently passed onto the module's upstream neighbor. The
67 action taken on messages with control portions will be as fol‐
68 lows:
69 o Any data messages with control portions have the
71 control portions removed from the message before to
72 passing the message on to the upstream neighbor.
73 o Messages that represent an orderly release indica‐
75 tion from the transport provider generate a zero
76 length data message, indicating the end of file,
77 which will be sent to the reader of the stream. The
78 orderly release message itself is freed by the mod‐
79 ule.
80 o Messages that represent an abortive disconnect
82 indication from the transport provider cause all
83 further write and putmsg system calls to fail with
84 errno set to ENXIO. All further read and getmsg
85 system calls return zero length data (indicating
86 end of file) once all previous data has been read.
87 o With the exception of the above rules, all other
89 messages with control portions generate an error
90 and all further system calls associated with the
91 stream will fail with errno set to EPROTO.
92 Any zero length data messages are freed by the module and they
93 are not passed onto the module's upstream neighbor.
94 pop When the module is popped off the stream or the stream is
97 closed, the module takes the following action:
98 o If an orderly release indication has been previ‐
100 ously received, then an orderly release request
101 will be sent to the remote side of the transport
102 connection.
103
106 Intro(3), getmsg(2), putmsg(2), read(2), write(2), Intro(3),
107 streamio(7I), timod(7M)
108 STREAMS Programming Guide
111SunOS 5.11 3 Jul 1990 tirdwr(7M)