Tribblix: manual page: setsockopt.3xnet

SETSOCKOPT(3XNET) X/Open Networking Services Library Functions

NAME

setsockopt - set the socket options

SYNOPSIS

cc [ flag... ] file... -lxnet [ library... ]
#include <sys/socket.h>

int setsockopt(int socket, int level, int option_name,
const void*option_value, socklen_t option_len);

DESCRIPTION

The setsockopt() function sets the option specified by the
option_name argument, at the protocol level specified by the level
argument, to the value pointed to by the option_value argument for
the socket associated with the file descriptor specified by the
socket argument.

The level argument specifies the protocol level at which the option
resides. To set options at the socket level, specify the level
argument as SOL_SOCKET. To set options at other levels, supply the
appropriate protocol number for the protocol controlling the option.
For example, to indicate that an option will be interpreted by the
TCP (Transport Control Protocol), set level to the protocol number of
TCP, as defined in the<netinet/in.h> header, or as determined by
using getprotobyname(3XNET).

The option_name argument specifies a single option to set. The
option_name argument and any specified options are passed
uninterpreted to the appropriate protocol module for interpretations.
The <sys/socket.h> header defines the socket level options. The
options are as follow

SO_DEBUG
Turns on recording of debugging information. This
option enables or disables debugging in the
underlying protocol modules. This option takes an
int value. This is a boolean option.

SO_BROADCAST
Permits sending of broadcast messages, if this is
supported by the protocol. This option takes an int
value. This is a boolean option.

SO_REUSEADDR
Specifies that the rules used in validating
addresses supplied to bind(3XNET) should allow reuse
of local addresses, if this is supported by the
protocol. This option takes an int value. This is a
boolean option.

SO_KEEPALIVE
Keeps connections active by enabling the periodic
transmission of messages, if this is supported by
the protocol. This option takes an int value.

If the connected socket fails to respond to these
messages, the connection is broken and threads
writing to that socket are notified with a SIGPIPE
signal.

This is a boolean option.

SO_LINGER
Lingers on a close(2) if data is present. This
option controls the action taken when unsent
messages queue on a socket and close(2) is
performed. If SO_LINGER is set, the system blocks
the process during close(2) until it can transmit
the data or until the time expires. If SO_LINGER is
not specified, and close(2) is issued, the system
handles the call in a way that allows the process to
continue as quickly as possible. This option takes
a linger structure, as defined in the <sys/socket.h>
header, to specify the state of the option and
linger interval.

SO_OOBINLINE
Leaves received out-of-band data (data marked
urgent) in line. This option takes an int value.
This is a boolean option.

SO_SNDBUF
Sets send buffer size. This option takes an int
value.

SO_RCVBUF
Sets receive buffer size. This option takes an int
value.

SO_DONTROUTE
Requests that outgoing messages bypass the standard
routing facilities. The destination must be on a
directly-connected network, and messages are
directed to the appropriate network interface
according to the destination address. The effect, if
any, of this option depends on what protocol is in
use. This option takes an int value. This is a
boolean option.

SO_MAC_EXEMPT
Sets the mandatory access control on the socket. A
socket that has this option enabled can communicate
with an unlabeled peer if the socket is in the
global zone or has a label that dominates the
default label of the peer. Otherwise, the socket
must have a label that is equal to the default label
of the unlabeled peer. SO_MAC_EXEMPT is a boolean
option that is available only when the system is
configured with Trusted Extensions.

SO_ALLZONES
Bypasses zone boundaries (privileged). This option
stores an int value. This is a boolean option.

The SO_ALLZONES option can be used to bypass zone
boundaries between shared-IP zones. Normally, the
system prevents a socket from being bound to an
address that is not assigned to the current zone. It
also prevents a socket that is bound to a wildcard
address from receiving traffic for other zones.
However, some daemons which run in the global zone
might need to send and receive traffic using
addresses that belong to other shared-IP zones. If
set before a socket is bound, SO_ALLZONES causes the
socket to ignore zone boundaries between shared-IP
zones and permits the socket to be bound to any
address assigned to the shared-IP zones. If the
socket is bound to a wildcard address, it receives
traffic intended for all shared-IP zones and behaves
as if an equivalent socket were bound in each active
shared-IP zone. Applications that use the
SO_ALLZONES option to initiate connections or send
datagram traffic should specify the source address
for outbound traffic by binding to a specific
address. There is no effect from setting this option
in an exclusive-IP zone. Setting this option
requires the sys_net_config privilege. See zones(7).

For boolean options, 0 indicates that the option is disabled and 1
indicates that the option is enabled.

Options at other protocol levels vary in format and name.

USAGE

The setsockopt() function provides an application program with the
means to control socket behavior. An application program can use
setsockopt() to allocate buffer space, control timeouts, or permit
socket data broadcasts. The <sys/socket.h> header defines the
socket-level options available to setsockopt().

Options may exist at multiple protocol levels. The SO_ options are
always present at the uppermost socket level.

RETURN VALUES

Upon successful completion, setsockopt() returns 0. Otherwise, -1 is
returned and errno is set to indicate the error.

ERRORS

The setsockopt() function will fail if:

EBADF
The socket argument is not a valid file descriptor.

EDOM
The send and receive timeout values are too big to fit
into the timeout fields in the socket structure.

EFAULT
The option_value parameter can not be accessed or
written.

EINVAL
The specified option is invalid at the specified
socket level or the socket has been shut down.

EISCONN
The socket is already connected, and a specified
option can not be set while the socket is connected.

ENOPROTOOPT
The option is not supported by the protocol.

ENOTSOCK
The socket argument does not refer to a socket.

The setsockopt() function may fail if:

ENOMEM
There was insufficient memory available for the operation
to complete.

ENOBUFS
Insufficient resources are available in the system to
complete the call.

ENOSR
There were insufficient STREAMS resources available for
the operation to complete.

ATTRIBUTES