xti_tcp.3.man

This a separate release of the OpenSS7 X/Open XTI/TLI library, TLI modules (timod, tirdwr) and the I

transport providers will always return
.B T_INVALID
for this field.
.TP
.I servtype
.B XTI-TCP
supports only connection-oriented modes with orderly release.  TCP
conforming transport service providers will return
.BR T_COTS_ORD .
.TP
.I flags
.B XTI-TCP
supports orderly release but does not support orderly release data and
does not support sending null data.  TCP conforming transport service
providers will not return
.B T_ORDRELDATA
or
.B T_SNDZERO
flags.  TCP conforming transport service providers may return the
.B XPG4_1
flag.
.\"
.\"
.SS t_listen\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_listen (3)
with the additional considerations described here.
.PP
Upon successful return
.BR t_listen (3)
indicates an existing connection and not a connection indication.  Since user
data cannot be exchanged during the connection establishment phase,
.I call->udata.maxlen
must be set to zero (0) before the call to
.BR t_listen (3).
The
.I call->addr
structure contains the remote calling socket.
.PP
.B XTI-TCP
does not support the same semantics with regard to indication of
connections, acceptance of indicated connections, and negotiation of options
during connection establishment.  This is because the connection can be
internally accepted before an indication is given to the XTI/TLI user.  To be able
to establish proposed values of options of end-to-end significance before a
connection is accepted, the proposed values of options must be set on the
transport endpoint upon which the XTI/TLI user is listening with
.BR t_listen (3)
rather than being responded to at the time that the connection is accepted
with
.BR t_accept (3).
This makes the semantics of these XTI/TLI functions somewhat different than is
experienced for ISO/OSI conforming protocols.  This characteristic of using
XTI/TLI for internet protocols is described in XNS 5.2.
.[
xns 5.2
.]
.PP
Some TCP options of end-to-end significance should be set before a call to
.BR t_listen (3)
using
.BR t_optmgmt (3)
as follows:
.PP
In addition, any of the options described under
.BR t_accept (3),
above, may be set with
.BR t_optmgmt (3)
before the call to
.BR t_listen (3).
.\"
.\"
.SS t_look\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_open (3)
with the additional considerations described here.
.PP
As soon as a segment with the TCP urgent pointer set enters the TCP receive
buffer, the event
.B T_EXDATA
in indicated.
.B T_EXDATA
remains set until all data up to the byte pointed to by the TCP urgent pointer
has been received.  If the urgent pointer si updated, and the user has not yet
received the byte previously pointed to by the urgent pointer, the update is
invisible to the user.
.\"
.\"
.SS t_open\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_open (3)
with the additional considerations described here.
.PP
.BR t_open (3)
is called as the first step in the initialization of a transport endpoint.
This function returns various default characteristics of the underlying
transport protocol by setting fields in the
.B t_info
structure.  The following should be the values returned by the call to
.BR t_open (3)
and
.BR t_getinfo (3)
with the TCP transport provider.
.PP
.TS
center tab(:);
l|c|c.
_
Parameters:Before call:After call
_
name:x:/
oflag:x:/
info->addr:/:sizeof(struct sockaddr_in)
info->options:/:x
info->tsdu:/:0
info->etsdu:/:T_INFINITE
info->connect:/:T_INVALID
info->discon:/:T_INVALID
info->servtype:/:T_COTS_ORD
info->flags:/:0
_
.TE
.PP
The information returned in the
.I info
parameter to this XTI/TLI call has the same considerations as the
.I info
parameter returned in the call to
.BR t_getinfo (3),
described above.
.\"
.\"
.SS t_optmgmt\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_optmgmt (3)
with the additional considerations described here.
.PP
The options that may be set, retrieved or negotiated using the XTI/TLI library
call are described under
.RI \*(lq OPTIONS \*(rq,
above.
.\"
.\"
.SS t_rcvconnect\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_rcvconnect (3)
with the additional considerations described here.
.PP
Since user data cannot be exchanged during the connection establishment phase,
.I call->udata.maxlen
must be set to zero (0) before the call to
.BR t_rcvconnect (3).
On return, the
.I call->addr
structure contains the address of the remote calling endpoint.
.PP
.BR t_rcvconnect (3)
will return all options of end-to-end significance indicating their
negotiation status in the
.I status
field of the returned option.  Options of end-to-end significance that will
always be returned are as follows:
.PP
Options of local significance will only be returned if their negotiation was
requested in the corresponding call to
.BR t_connect (3).
Options of local significance that can be negotiated during connection
establishment are as follows:
.\"
.\"
.SS t_rcvdis\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_rcvdis (3)
with the additional considerations described here.
.PP
Since data cannot be sent with a disconnect,
.I call->udata.len
must be set to zero (0).
.PP
.B XTI-TCP
does not support disconnection data and the
.I dis->udata
parameter must always be empty.
.PP\
.I dis->reason
will either be a negative
.BR UNIX \(rg
error code, or a  TCP protocol-specific error code as follows:
.PP
For TCP, a disconnect indication may be received associated with a connection
indication before the connection indication is accepted or refused.  In this
case,
.I dis->sequence
will be set appropriately.
.PP
.I dis->reason
can also return the following negative error numbers:
.TP \w'[ECONNABORTED]\(em'u
.RB [ ECONNABORTED ]
software related connection abort.
.PD 0
.TP
.RB [ ECONNRESET ]
connection was reset by peer.
.TP
.RB [ ECONNREFUSED ]
connection was refused by peer.
.TP
.RB [ ETIMEDOUT ]
connection timed out.
.TP
.RB [ EPROTO ]
connection aborted due to protocol error.
.TP
.RB [ ENETDOWN ]
network is down.
.TP
.RB [ ENETUNREACH ]
network is unreachable.
.TP
.RB [ ENETRESET ]
network dropped connection because of reset.
.TP
.RB [ EHOSTDOWN ]
the destination host is down.
.TP
.RB [ EHOSTUNREACH ]
no route to destination host.
.TP
.RB [ ESHUTDOWN ]
SYN received while shutting down.
.PD
.\"
.\"
.SS t_rcv\fR(3), \fBt_rcvv\fR(3)
.PP
.B XTI-TCP
supports these XTI/TLI library calls as described in
.BR t_rcv "(3) and " t_rcvv
with the additional considerations described here.
.PP
The
.B T_MORE
flag should be ignored if normal data is delivered.  If a byte in the data
stream is pointed to by the TCP urgent pointer, as many bytes as possible
preceding this marked byte and the marked byte itself are denoted as urgent
data and are received with the
.BR T_EXPEDITED
flag set.  If the buffer supplied by the user is too small to hold all urgent
data, the
.B T_MORE
flag will be set, indicating that urgent data still remains to be read.  Note
that the number of bytes received with the
.B T_EXPEDITED
flag set is not necessarily equal to the number of bytes sent by the peer user
with the
.B T_EXPEDITED
flag set.
.PP
When data is received using these XTI/TLI library calls, the
.I flags
parameter will not have the
.B T_MORE
flag bit set.
The
.I flags
parameter will have the
.B T_EXPEDITED
flag bit set if the data was sent out-of-band.
.PP
Data received with these XTI/TLI library calls, or using
.BR read "(2) or " readv (2),
will set the
.IR T_IP_OPTIONS ", " T_IP_TOS " and " T_IP_TTL
to the option values associated with the read data if the local options (XXX)
are set for the transport endpoint.
.PP
Reads using
.BR read "(2) or " readv (2)
are stream based reads of normal (in-band) data.  For additional
.BR read "(2) or " readv (2)
behavior, see the
.IR I_SRDOPT " and " I_GRDOPT
input output controls under
.BR streamio (7).
For advanced
.BR read "(2) and " readv (2)
support, use the
.BR tirdwr (4)
pushable module.
.\"
.\"
.SS t_rcvreldata\fR(3)
.PP
.B XTI-TCP
does not support a orderly release with data and this XTI/TLI library call will
return a
.I t_errno
value of
.RB [ TNOTSUPPORT ].
.\"
.\"
.SS t_rcvrel\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_rcvrel (3)
without modification.
.BR t_rcvrel (3)
is preferred over
.BR t_snddis (3)
for disconnecting an established connection (i.e. a connection in the
.B T_DATAXFER
state.
.\"
.\"
.SS t_rcvudata\fR(3), \fBt_rcvvudata\fR(3)
.PP
.B XTI-TCP
does not support a connection-less mode and these XTI/TLI library calls will
return a
.I t_errno
value of
.RB [ TNOTSUPPORT ].
For a connection-less mode service, see
.BR xti_udp (3).
.\"
.\"
.SS t_rcvuderr\fR(3)
.PP
.B XTI-TCP
does not support a connection-less mode and these XTI/TLI library calls will
return a
.I t_errno
value of
.RB [ TNOTSUPPORT ].
For a connection-less mode service, see
.BR xti_udp (3).
.\"
.\"
.SS t_snddis\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_snddis (3)
with the additional considerations described here.
.PP
Since data may not be sent with a disconnect,
.I call->udata.len
must be set to zero (0).
.PP
.B XTI-TCP
does not support disconnection from specified responding addresses.
Therefore, the
.I call->addr
parameter should be empty and will always be ignored.  TCP does not support
disconnect data or disconnect options.  The parameters
.I call->udata
and
.I call->opt
must always be empty.
.B XTI-TCP
does not support refusal of connection indications, and the
.I call->sequence
parameter is populated as described in
.BR t_snddis (3).
.\"
.\"
.SS t_snd\fR(3), \fBt_sndv\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_snd "(3) and " t_sndv (3)
with the additional considerations described here.
.PP
When data is send using these XTI/TLI library calls, the
.B T_MORE
flag bit in the
.I flags
parameter should always be set and will be ignored by the transport service
provider.
The
.B T_EXPEDITED
flag bit should be set in the
.I flags
parameter if the data to be sent is out-of-band data.
.PP
Writes using
.BR write "(2) or " writev (2)
are stream based writes of normal (in-band) data.  For additional
.BR write "(2) or " writev (2)
behavior, see the
.IR I_SWROPT " and " I_GWROPT
input output controls under
.BR streamio (7).
For advanced
.BR write "(2) and " writev (2)
support, use the
.BR tirdwr (4)
pushable module.
.\"
.\"
.SS t_sndreldata\fR(3)
.PP
.B XTI-TCP
does not support a orderly release with data and this XTI/TLI library call will
return a
.I t_errno
value of
.RB [ TNOTSUPPORT ].
.\"
.\"
.SS t_sndrel\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_sndrel (3)
without modification.
.\"
.\"
.SS t_sndudata\fR(3), \fBt_sndvudata\fR(3)
.PP
.B XTI-TCP
does not support a connection-less mode and these XTI/TLI library calls will
return a
.I t_errno
value of
.RB [ TNOTSUPPORT ].
For a connection-less mode service, see
.BR xti_udp (3).
.\"
.\"
.SS t_unbind\fR(3)
.PP
.B XTI-TCP
supports this XTI/TLI library call as described in
.BR t_rcvrel (3)
with the additional considerations described here.
.\"
.\"
.SH "BUGS"
.PP
Although
.BR XTI-TCP
has no known bugs, the
.BR INET (4)
implementation of
.B XTI-TCP
has not been conformance tested.
.\"
.\"
.SH "CAVEATS"
.PP
In support of the
.BR sockets (3)
library for
.BR tpi (7)
transport providers, the options described here have been made compatible with
the socket options described in
.BR tcp (7).
As a result, depending on the release of 
.BR INET (4),
the XTI/TLI options described might not be compatible with the options described
here.
.PP
The
.B Linux
socket version of TCP described in
.BR tcp (7),
accessed using the TPI interface of the
.B strinet
package described in
.BR INET (4),
supports all of the options described here.
.PP
Earlier version of the
.BR INET (4)
driver did not support wildcard binds.  If an attempt was made to bind to a
wildcard address or port number, the bind would fail with
.RB [ TNOADDR ].
While this is correct behavior, it was not consistent with other
.B XTI-TCP
implemetnations.  Recent versions of the
.BR INET (4)
driver include the ability to bind to wildcards or to request that the
transport service provider asign a suitable address.
.\"
.\"
.SH "SEE ALSO"
.PP
.BR INET (4),
.BR read (2),
.BR readv (2),
.BR tcp (4),
.BR tcp (7),
.BR sockets (3),
.BR t_accept (3),
.BR t_connect (3),
.BR T_CONN_REQ (7),
.BR tcp (7),
.BR t_errno (3),
.BR t_getinfo (3),
.BR timod (4),
.BR tirdwr (4),
.BR t_listen (3),
.BR T_OPTDATA_IND (7),
.BR t_optmgmt (3),
.BR t_rcvconnect (3),
.BR t_snddis (3),
.BR write (2),
.BR writev (2),
.BR xnet (3),
.BR xti (3),
.BR xti_ip (3),
.BR xti_tcp (3).
.\"
.\"
.SH "DEVICES"
.PP
There is one TCP device providing the Transport Provider Interface that
provide TCP conforming TPI devices as follows:
.\"
.\"
.TP
.IR /dev/tcp ", " /dev/inet/tcp
For more information on the TPI TCP device, see
.BR tcp (4).
.\"
.\"
.SH "VERSIONS"
.PP
The
.B TCP-TPI
driver is specific to the
.B OpenSS7
stack.
This is an unofficial Corrigendum to XNS 5.2 Revision 2.
.[
xns
.]
.\"
.\"
.[
$LIST$
.]
.T4