xti_sctp.3.man

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

.BR t_optmgmt (3)
See
.IR T_IP_OPTIONS .
.\"
.\"
.TP
.B T_IP_RETOPTS
Determine whether a
.I T_IP_RETOPTS
option indicating the IP options for the received packet will be
included in a
.BR T_OPTDATA_IND (7)
messge as well as reflected in the response to the current value
.B T_GET
operation to
.BR t_optmgmt (3).
The option value is a
.B t_scalar_t
with valid values
.BR T_YES " or " T_NO .
This option is for use with
.BR t_optmgmt (3).
.sp
This option is for use with the
.BR sockets (3)
library.
For
.BR xti (3)
it changes the semantics of the value returned to a
.B T_GET
operation to
.BR t_optmgmt (3).
When set to
.BR T_YES ,
the current value obtained with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the value of the last received message.
When set to
.BR T_NO ,
the current value obtains with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the default value or the value last set with a
.B T_NEGOTIATE
operation to
.BR t_optmgmt (3)
For additional information, see
.BR xti_ip (3).
.\"
.\"
.TP
.B T_IP_TOS
This option determines the type of service to be used in IP packets associated
with a subsequent data transmission.
The option value is formatted as a
.B t_scalar_t
that contains the type of service value.
This option is used with
.BR t_optmgmt (3).
The current value that is set will be used on all packets went with
.BR t_snd "(3), " t_sndv "(3), " write "(2) or " writev (2).
.I T_IP_RECVTOS
is set, the current value, when read, using
.BR t_optmgmt (3),
will return the value that was contained in the last IP packet read (or
partially read) with
.BR t_rcv "(3), " t_rcvv "(3), " read "(2) or " readv (2).
See
.BR xti_ip (3)
for additional information.
.\"
.\"
.TP
.B T_IP_TTL
This option determines the time to live to be used in IP packets associated
with a subsequent data transmission.
The option value is formatted as a
.B t_scalar_t
that contains the time to live value.
This option is used with
.BR t_optmgmt (3).
The current value that is set will be used on all packets went with
.BR t_snd "(3), " t_sndv "(3), " write "(2) or " writev (2).
.I T_IP_RECVTOS
is set, the current value, when read, using
.BR t_optmgmt (3),
will return the value that was contained in the last IP packet read (or
partially read) with
.BR t_rcv "(3), " t_rcvv "(3), " read "(2) or " readv (2).
See
.BR xti_ip (3)
for additional information.
.\"
.\"
.TP
.B T_IP_MTU
This option is a read-only option that returns the value of the Path MTU for the
SCTP association.
See SCTP level options for a mechanism for obtaining MTU on a per-destination
basis.  When the peer is not multi-homed, this option returns the same value
as would be obtained on a per-destination basis (because there is only one
destination).
See
.BR xti_ip (3)
for additional information.
.\"
.\"
.TP
.B T_IP_RECVERR
Not supported.
.\"
.\"
.TP
.B T_IP_PMTU_DISCOVER
Supported for SCTP transport service providers without modification.  See
.BR xti_ip (3)
for additional information.
.\"
.\"
.SS "T_INET_SCTP"
.PP
Options within this level are specific to the Stream Control Transmission
Protocol (SCTP) yet are used by protocol levels using SCTP transport.
.PP
The options defined with the option level
.B T_INET_SCTP
are as follows:
.\"
.\"
.TP
.B T_SCTP_NODELAY
This option determines whether to delay transmission of data to attempt to
coalesce smaller packets into larger packets.
The option value is formatted as a
.B t_uscalar_t
that can have the values
.BR T_YES " or " T_NO .
When set to
.BR T_YES ,
it conveys that packets are not to be delayed to coalesce smaller packets.
When set to
.BR T_NO ,
it conveys that packets are being delayed to coalesce smaller packets.
This option is used with
.BR t_optmgmt (3).
.sp
This option parallels the
.I T_TCP_NODELAY
option for compatibility with
.BR xti_tcp (3).
.IR T_SCTP_NODELAY " and " T_TCP_NODELAY
can be used interchangeably.
.sp
When Nagle is enabled,
.B SCTP
uses the Nagle algorithm
.[
RFC 896
.]
for bundling DATA chunks into a packet.  This results in far fewer short
packets in the network.  The algorithm is that described in RFC 896
.[
RFC 896
.]
ane RFC 1122
.[
RFC 1122
.]
with the Minshall modifications to accommodate delayed SACK as described in
draft-minshall-nagle-01.txt.
.[
minshall-nagle-01
.]
(Note: later version of
.BR tcp (7)
also include the Minshall modification).
.\"
.\"
.TP
.B T_SCTP_MAXSEG
This option determines the maximum segment size for outgoing packets.  Values
greater thatn the association MTU are ignored and have no effect.  This
parallels the
.I T_TCP_MAXSEG
option for compatibility with
.BR xti_tcp (3).
.IR T_SCTP_MAXSEG " and " T_TCP_MAXSEG
can be used interchangeably.
.sp
This value determines the maximum size (in bytes) above which SCTP will
fragment larger DATA chunks into smaller DATA chunks, and beneath which SCTP
will bundle DATA chunks into a single packet or combined smaller DATA chunks
into larger DATA chunks.  Normally this value is the association MTU value
minus the size of the current IP and SCTP headers, minus the size of one DATA
chunk header.  If the user sets this to a lower value, the lower value will be
used.
.sp
This option is formatted as a
.B t_scalar_t
indicating the maximum size in bytes.
This option is used with
.BR t_optmgmt (3).
.\"
.\"
.TP
.B T_SCTP_CORK
This option determines whether to cork the transmission stream waiting for
subsequent packets.  When set, this option permits a number of
.BR t_snd (3)
operations to be performed without sending the data subsequent to the cork.
When the cork is released, all subsequent data will be permitted to proceed.
The option is formatted as a
.B t_scalar_t
that can have the values
.BR T_YES ,
conveying that transmission is corked, or
.BR T_NO ,
conveying that transmission is uncorked.
THis option is used with
.BR t_optmgmt (3).
.\"
.\"
.TP
.B T_SCTP_SID
This option determines the SCTP Stream Identifier that is to be associated
with a given data transmission.  The option value is formatted as a
.B t_scalar_t
that contains the numeric value of the SCTP Stream Identifier.  This options
is used with
.BR t_optmgmt (3).
The current value that is set will be used on all packets sent with
.BR t_snd "(3), " t_sndv "(3), " write "(2) or " writev (2).
When option
.I T_SCTP_RECVSID
is set, the current value, when read, using
.BR t_optmgmt (3),
will return the value that was contained in the last packet read with
.BR t_rcv "(3), " t_rcvv "(3), " read "(2) or " readv (2).
See
.IR T_SCTP_RECVSID .
.\"
.\"
.TP
.B T_SCTP_PPI
This option determines the SCTP Payload Protocol Identifier that is to be
associated with a given data transmission.  The option value is formatted as a
.B t_scalar_t
that contains the numeric value of the SCTP Payload Protocol Identifier.  This
option is used with
.BR t_optmgmt (3).
The current value that is set will be used on all packets sent with
.BR t_snd "(3), " t_sndv "(3), " write "(2) or " writev (2).
When option
.I T_SCTP_RECVPPI
is set, the current value, when read, using
.BR t_optmgmt (3),
will return the value that was contained in the last packet read with
.BR t_rcv "(3), " t_rcvv "(3), " read "(2) or " readv (2).
See
.IR T_SCTP_RECVPPI .
.\"
.\"
.TP
.B T_SCTP_RECVSID
Determine whether a
.I T_SCTP_SID
option
indicating the SCTP Stream Identifier of the received data
will be included in a
.BR T_OPTDATA_IND (7)
message as well as reflected in the response to a current value
.B T_GET
operation to
.BR t_optmgmt (3).
The option value is a
.B t_scalar_t
with valid values
.BR T_YES " or " T_NO .
This option is for use with
.BR t_optmgmt (3).
.sp
This option is for use with the
.BR sockets (3)
library.
For
.BR xti (3)
it changes the semantics of the value returned to a
.B T_GET
operation to
.BR t_optmgmt (3).
When set to
.BR T_YES ,
the current value obtained with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the value of the last received message.
When set to
.BR T_NO ,
the current value obtains with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the default value or the value last set with a
.B T_NEGOTIATE
operation to
.BR t_optmgmt (3)
See
.IR T_SCTP_SID .
.\"
.\"
.TP
.B T_SCTP_RECVPPI
Determine whether a
.I T_SCTP_PPI
option
indicating the SCTP Payload Protocol Identifier of the received data
will be included in a
.BR T_OPTDATA_IND (7)
message as well as reflected in the response to a current value
.B T_GET
operation to
.BR t_optmgmt (3).
The option value is a
.B t_scalar_t
with valid values
.BR T_YES " or " T_NO .
This option is for use with
.BR t_optmgmt (3).
.sp
This option is for use with the
.BR sockets (3)
library.
For
.BR xti (3)
it changes the semantics of the value returned to a
.B T_GET
operation to
.BR t_optmgmt (3).
When set to
.BR T_YES ,
the current value obtained with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the value of the last received message.
When set to
.BR T_NO ,
the current value obtains with a
.B T_GET
operation to
.BR t_optmgmt (3)
will be the default value or the value last set with a
.B T_NEGOTIATE
operation to
.BR t_optmgmt (3)
See
.IR T_SCTP_PPI .
.\"
.\"
.TP
.B T_SCTP_HEARTBEAT_ITVL
This option determines the time interval (in seconds) between successive
HEARTBEAT messages used to probe destination transport addresses for RTT
calculation and activity.  This option is formatted as a
.BR t_scalar_t .
Valud values are zero (0), indicating do not heartbeat, or a value of 1 second
or greater indicating the heartbeat interval.
This options is used with
.BR t_optmgmt "(3), " t_connect "(3) or " t_accept (3).
.sp
The value set with
.BR t_optmgmt (3)
is the value that will be assigned to new destinations.
To be effective, this option must be set with the call to
.BR t_connect "(3) or before the call to " t_listen (3),
or when a passive connection indication is accepted with
.BR t_accept (3).
Active destinations can be controlled with the option
.IR T_SCTP_HB ,
below.
.\"
.\"
.TP
.B T_SCTP_HB
This option determines the heartbeat activation and interval associated with
a specific destination address.  The option value is a
.B t_sctp_hb
structure.  This option will return an error if it is attempted on a stream in
the unconnected state.  The
.B t_sctp_hb
structure is formatted as follows:
.sp
.nf
\fC\s-1\
typedef struct t_sctp_hb {
    uint32_t hb_dest;        /* destination address */
    t_uscalar_t hb_onoff;    /* activation flag */
    t_uscalar_t hb_itvl;     /* interval in milliseconds */
} t_sctp_hb_t;
\s+1\fR
.fi
.sp
The
.B t_sctp_hb
structure has the following fields:
.RS
.TP \w'hb_onoff\(em'u
.I hb_dest
is the
.B sockaddr_in
structure that contains the destination address to which the heartbeat setting
applies.
.PD 0
.TP
.I hb_onoff
is an integer boolean activation flag indicating whether heartbeat is active
on the destination.
.TP
.I hb_itvl
is the integer heartbeat interval in milliseconds.
.PD
.PP
This option is intended to be used with
.BR t_optmgmt "(3).
.I dest
must be one of the valid addresses associated with the connection.
Note that heartbeat activity can also be set on an association basis using the
option
.IR T_SCTP_HEARTBEAT_ITVL .
.RE
.\"
.\"
.TP
.B T_SCTP_RTO_INITIAL
This option determines the time interval (in milliseconds) that will be used
as an initial RTO (Retransmission Time Out) value when sending packets to a
destination for the first time.
This option if formatted as a
.BR t_scalar_t .
Valid values are zero or greater and must be within the range from
.IR T_SCTP_RTO_MIN " to " T_SCTP_RTO_MAX .
To be effective, this option must be set with the call to
.BR t_connect "(3) or before the call to " t_listen (3),
or when a passive connection indication is accepted with
.BR t_accept (3).
Active destinations can be controlled with the option
.IR T_SCTP_RTO ,
below.
.\"
.\"
.TP
.B T_SCTP_RTO_MIN
Determine the time interval (in milliseconds) that will be used as a minimum