BSD 4_3_Net_2 release

[unix-history] / usr / src / lib / libc / sys / getsockopt.2

diff --git a/usr/src/lib/libc/sys/getsockopt.2 b/usr/src/lib/libc/sys/getsockopt.2
index ee1b730..ceab2b6 100644 (file)
--- a/usr/src/lib/libc/sys/getsockopt.2
+++ b/usr/src/lib/libc/sys/getsockopt.2
@@ -1,210 +1,372 @@
-.\" Copyright (c) 1983 The Regents of the University of California.
+.\" Copyright (c) 1983, 1991 The Regents of the University of California.

 .\" All rights reserved.
 .\"
 .\" All rights reserved.
 .\"

-.\" Redistribution and use in source and binary forms are permitted provided
-.\" that: (1) source distributions retain this entire copyright notice and
-.\" comment, and (2) distributions including binaries display the following
-.\" acknowledgement:  ``This product includes software developed by the
-.\" University of California, Berkeley and its contributors'' in the
-.\" documentation or other materials provided with the distribution and in
-.\" all advertising materials mentioning features or use of this software.
-.\" Neither the name of the University nor the names of its contributors may
-.\" be used to endorse or promote products derived from this software without
-.\" specific prior written permission.
-.\" THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR IMPLIED
-.\" WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF
-.\" MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.

 .\"
 .\"

-.\"    @(#)getsockopt.2        6.6 (Berkeley) 6/23/90
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.

 .\"
 .\"

-.TH GETSOCKOPT 2 "June 23, 1990"
-.UC 5
-.SH NAME
-getsockopt, setsockopt \- get and set options on sockets
-.SH SYNOPSIS
-.nf
-.ft B
-#include <sys/types.h>
-#include <sys/socket.h>
-.PP
-.ft B
-getsockopt(s, level, optname, optval, optlen)
-int s, level, optname;
-char *optval;
-int *optlen;
-.sp
-setsockopt(s, level, optname, optval, optlen)
-int s, level, optname;
-char *optval;
-int optlen;
-.fi
-.SH DESCRIPTION
-.I Getsockopt
+.\"     @(#)getsockopt.2       6.9 (Berkeley) 5/1/91
+.\"
+.\" Copyright (c) 1983, 1991 The Regents of the University of California.
+.\" All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 3. All advertising materials mentioning features or use of this software
+.\"    must display the following acknowledgement:
+.\"    This product includes software developed by the University of
+.\"    California, Berkeley and its contributors.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)getsockopt.2       6.9 (Berkeley) 5/1/91
+.\"
+.Dd May 1, 1991
+.Dt GETSOCKOPT 2
+.Os BSD 4.3r
+.Sh NAME
+.Nm getsockopt ,
+.Nm setsockopt
+.Nd get and set options on sockets
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/socket.h>
+.Ft int
+.Fn getsockopt "int s" "int level" "int optname" "void *optval" "int *optlen"
+.Ft int
+.Fn setsockopt "int s" "int level" "int optname" "const void *optval" "int optlen"
+.Sh DESCRIPTION
+.Fn Getsockopt

 and
 and

-.I setsockopt
-manipulate
-.I options
+.Fn setsockopt
+manipulate the
+.Em options

 associated with a socket.  Options may exist at multiple
 protocol levels; they are always present at the uppermost
 associated with a socket.  Options may exist at multiple
 protocol levels; they are always present at the uppermost

-``socket'' level.
-.PP
+.Dq socket
+level.
+.Pp

 When manipulating socket options the level at which the
 option resides and the name of the option must be specified.
 When manipulating socket options the level at which the
 option resides and the name of the option must be specified.

-To manipulate options at the ``socket'' level,
-.I level
-is specified as SOL_SOCKET.  To manipulate options at any
+To manipulate options at the socket level,
+.Fa level
+is specified as
+.Dv SOL_SOCKET .
+To manipulate options at any

 other level the protocol number of the appropriate protocol
 controlling the option is supplied.  For example,
 other level the protocol number of the appropriate protocol
 controlling the option is supplied.  For example,

-to indicate that an option is to be interpreted by the TCP protocol,
-.I level
-should be set to the protocol number of TCP; see
-.IR getprotoent (3N).
-.PP
+to indicate that an option is to be interpreted by the
+.Tn TCP
+protocol,
+.Fa level
+should be set to the protocol number of
+.Tn TCP ;
+see
+.Xr getprotoent 3 .
+.Pp

 The parameters
 The parameters

-.I optval
+.Fa optval

 and
 and

-.I optlen
+.Fa optlen

 are used to access option values for
 are used to access option values for

-.IR setsockopt .
+.Fn setsockopt .

 For
 For

-.I getsockopt
+.Fn getsockopt

 they identify a buffer in which the value for the
 requested option(s) are to be returned.  For
 they identify a buffer in which the value for the
 requested option(s) are to be returned.  For

-.IR getsockopt ,
-.I optlen
+.Fn getsockopt ,
+.Fa optlen

 is a value-result parameter, initially containing the
 size of the buffer pointed to by
 is a value-result parameter, initially containing the
 size of the buffer pointed to by

-.IR optval ,
+.Fa optval ,

 and modified on return to indicate the actual size of
 the value returned.  If no option value is
 to be supplied or returned,
 and modified on return to indicate the actual size of
 the value returned.  If no option value is
 to be supplied or returned,

-.I optval
-may be supplied as 0.
-.PP
-.I Optname
+.Fa optval
+may be NULL.
+.Pp
+.Fa Optname

 and any specified options are passed uninterpreted to the appropriate
 protocol module for interpretation.
 The include file
 and any specified options are passed uninterpreted to the appropriate
 protocol module for interpretation.
 The include file

-.RI < sys/socket.h >
-contains definitions for ``socket'' level options, described below.
+.Ao Pa sys/socket.h Ac
+contains definitions for
+socket level options, described below.

 Options at other protocol levels vary in format and
 Options at other protocol levels vary in format and

-name; consult the appropriate entries in section (4P).
-.PP
-Most socket-level options take an
-.I int
+name; consult the appropriate entries in
+section
+4 of the manual.
+.Pp
+Most socket-level options utilize an
+.Fa int

 parameter for
 parameter for

-.IR optval .
+.Fa optval .

 For
 For

-.IR setsockopt ,
-the parameter should non-zero to enable a boolean option,
+.Fn setsockopt ,
+the parameter should be non-zero to enable a boolean option,

 or zero if the option is to be disabled.
 or zero if the option is to be disabled.

-SO_LINGER uses a
-.I struct linger
+.Dv SO_LINGER
+uses a
+.Fa struct linger

 parameter, defined in
 parameter, defined in

-.RI < sys/socket.h >,
+.Ao Pa sys/socket.h Ac ,

 which specifies the desired state of the option and the
 linger interval (see below).
 which specifies the desired state of the option and the
 linger interval (see below).

-.PP
+.Dv SO_SNDTIMEO
+and
+.Dv SO_RCVTIMEO
+use a
+.Fa struct timeval
+parameter, defined in
+.Ao Pa sys/time.h Ac .
+.Pp

 The following options are recognized at the socket level.
 Except as noted, each may be examined with
 The following options are recognized at the socket level.
 Except as noted, each may be examined with

-.I getsockopt
+.Fn getsockopt

 and set with
 and set with

-.IR setsockopt .
-.PP
-.RS
-.ta \w'SO_BROADCAST\ \ \ \ 'u
-.nf
-SO_DEBUG       toggle recording of debugging information
-SO_REUSEADDR   toggle local address reuse
-SO_KEEPALIVE   toggle keep connections alive
-SO_DONTROUTE   toggle routing bypass for outgoing messages
-SO_LINGER      linger on close if data present
-SO_BROADCAST   toggle permission to transmit broadcast messages
-SO_OOBINLINE   toggle reception of out-of-band data in band
-SO_SNDBUF      set buffer size for output
-SO_RCVBUF      set buffer size for input
-SO_TYPE        get the type of the socket (get only)
-SO_ERROR       get and clear error on the socket (get only)
-.fi
-.RE
-.PP
-SO_DEBUG enables debugging in the underlying protocol modules.
-SO_REUSEADDR indicates that the rules used in validating addresses supplied
+.Fn setsockopt .
+.Bl -column SO_OOBINLINE -offset indent
+.It Dv SO_DEBUG Ta "enables recording of debugging information"
+.It Dv SO_REUSEADDR Ta "enables local address reuse"
+.It Dv SO_KEEPALIVE Ta "enables keep connections alive"
+.It Dv SO_DONTROUTE Ta "enables routing bypass for outgoing messages"
+.It Dv SO_LINGER  Ta "linger on close if data present"
+.It Dv SO_BROADCAST Ta "enables permission to transmit broadcast messages"
+.It Dv SO_OOBINLINE Ta "enables reception of out-of-band data in band"
+.It Dv SO_SNDBUF Ta "set buffer size for output"
+.It Dv SO_RCVBUF Ta "set buffer size for input"
+.It Dv SO_SNDLOWAT Ta "set minimum count for output"
+.It Dv SO_RCVLOWAT Ta "set minimum count for input"
+.It Dv SO_SNDTIMEO Ta "set timeout value for output"
+.It Dv SO_RCVTIMEO Ta "set timeout value for input"
+.It Dv SO_TYPE Ta "get the type of the socket (get only)"
+.It Dv SO_ERROR Ta "get and clear error on the socket (get only)"
+.El
+.Pp
+.Dv SO_DEBUG
+enables debugging in the underlying protocol modules.
+.Dv SO_REUSEADDR
+indicates that the rules used in validating addresses supplied

 in a
 in a

-.IR bind (2)
-call should allow reuse of local addresses.  SO_KEEPALIVE enables the
+.Xr bind 2
+call should allow reuse of local addresses.
+.Dv SO_KEEPALIVE
+enables the

 periodic transmission of messages on a connected socket.  Should the
 connected party fail to respond to these messages, the connection is
 considered broken and processes using the socket are notified via a
 periodic transmission of messages on a connected socket.  Should the
 connected party fail to respond to these messages, the connection is
 considered broken and processes using the socket are notified via a

-SIGPIPE signal.  SO_DONTROUTE indicates that outgoing messages should
+.Dv SIGPIPE
+signal when attempting to send data.
+.Dv SO_DONTROUTE
+indicates that outgoing messages should

 bypass the standard routing facilities.  Instead, messages are directed
 to the appropriate network interface according to the network portion
 of the destination address.
 bypass the standard routing facilities.  Instead, messages are directed
 to the appropriate network interface according to the network portion
 of the destination address.

-.PP
-SO_LINGER controls the action taken when unsent messags
+.Pp
+.Dv SO_LINGER
+controls the action taken when unsent messags

 are queued on socket and a 
 are queued on socket and a 

-.IR close (2)
+.Xr close 2

 is performed.
 is performed.

-If the socket promises reliable delivery of data and SO_LINGER is set,
+If the socket promises reliable delivery of data and
+.Dv SO_LINGER is set,

 the system will block the process on the 
 the system will block the process on the 

-.I close
+.Xr close

 attempt until it is able to transmit the data or until it decides it
 is unable to deliver the information (a timeout period, termed the
 linger interval, is specified in the
 attempt until it is able to transmit the data or until it decides it
 is unable to deliver the information (a timeout period, termed the
 linger interval, is specified in the

-.IR setsockopt 
-call when SO_LINGER is requested). 
-If SO_LINGER is disabled and a 
-.I close
+.Fn setsockopt
+call when
+.Dv SO_LINGER
+is requested). 
+If
+.Dv SO_LINGER
+is disabled and a 
+.Xr close

 is issued, the system will process the close in a manner that allows
 the process to continue as quickly as possible.
 is issued, the system will process the close in a manner that allows
 the process to continue as quickly as possible.

-.PP
-The option SO_BROADCAST requests permission to send broadcast datagrams
+.Pp
+The option
+.Dv SO_BROADCAST
+requests permission to send broadcast datagrams

 on the socket.
 Broadcast was a privileged operation in earlier versions of the system.
 on the socket.
 Broadcast was a privileged operation in earlier versions of the system.

-With protocols that support out-of-band data, the SO_OOBINLINE option
+With protocols that support out-of-band data, the
+.Dv SO_OOBINLINE
+option

 requests that out-of-band data be placed in the normal data input queue
 as received; it will then be accessible with
 requests that out-of-band data be placed in the normal data input queue
 as received; it will then be accessible with

-.I recv
+.Xr recv

 or
 or

-.I read
-calls without the MSG_OOB flag.
-SO_SNDBUF and SO_RCVBUF are options to adjust the normal
+.Xr read
+calls without the
+.Dv MSG_OOB
+flag.
+Some protocols always behave as if this option is set.
+.Dv SO_SNDBUF
+and
+.Dv SO_RCVBUF
+are options to adjust the normal

 buffer sizes allocated for output and input buffers, respectively.
 The buffer size may be increased for high-volume connections,
 or may be decreased to limit the possible backlog of incoming data.
 The system places an absolute limit on these values.
 buffer sizes allocated for output and input buffers, respectively.
 The buffer size may be increased for high-volume connections,
 or may be decreased to limit the possible backlog of incoming data.
 The system places an absolute limit on these values.

-Finally, SO_TYPE and SO_ERROR are options used only with
-.IR setsockopt .
-SO_TYPE returns the type of the socket, such as SOCK_STREAM;
+.Pp
+.Dv SO_SNDLOWAT
+is an option to set the minimum count for output operations.
+Most output operations process all of the data supplied
+by the call, delivering data to the protocol for transmission
+and blocking as necessary for flow control.
+Nonblocking output operations will process as much data as permitted
+subject to flow control without blocking, but will process no data
+if flow control does not allow the smaller of the low water mark value
+or the entire request to be processed.
+A
+.Xr select 2
+operation testing the ability to write to a socket will return true
+only if the low water mark amount could be processed.
+The default value for
+.Dv SO_SNDLOWAT
+is set to a convenient size for network efficiency, often 1024.
+.Dv SO_RCVLOWAT
+is an option to set the minimum count for input operations.
+In general, receive calls will block until any (non-zero) amount of data
+is received, then return with smaller of the amount available or the amount
+requested.
+The default value for
+.Dv SO_SNDLOWAT
+is 1.
+If 
+.Dv SO_SNDLOWAT
+is set to a larger value, blocking receive calls normally
+wait until they have received the smaller of the low water mark value
+or the requested amount.
+Receive calls may still return less than the low water mark if an error
+occurs, a signal is caught, or the type of data next in the receive queue
+is different than that returned.
+.Pp
+.Dv SO_SNDTIMEO
+is an option to set a timeout value for output operations.
+It accepts a
+.Fa struct timeval
+parameter with the number of seconds and microseconds
+used to limit waits for output operations to complete.
+If a send operation has blocked for this much time,
+it returns with a partial count
+or with the error
+.Er EWOULDBLOCK
+if no data were sent.
+In the current implementation, this timer is restarted each time additional
+data are delivered to the protocol,
+implying that the limit applies to output portions ranging in size
+from the low water mark to the high water mark for output.
+.Dv SO_RCVTIMEO
+is an option to set a timeout value for input operations.
+It accepts a
+.Fa struct timeval
+parameter with the number of seconds and microseconds
+used to limit waits for input operations to complete.
+In the current implementation, this timer is restarted each time additional
+data are received by the protocol,
+and thus the limit is in effect an inactivity timer.
+If a receive operation has been blocked for this much time without
+receiving additional data, it returns with a short count
+or with the error
+.Er EWOULDBLOCK
+if no data were received.
+.Pp
+Finally,
+.Dv SO_TYPE
+and
+.Dv SO_ERROR
+are options used only with
+.Fn setsockopt .
+.Dv SO_TYPE
+returns the type of the socket, such as
+.Dv SOCK_STREAM ;

 it is useful for servers that inherit sockets on startup.
 it is useful for servers that inherit sockets on startup.

-SO_ERROR returns any pending error on the socket and clears
+.Dv SO_ERROR
+returns any pending error on the socket and clears

 the error status.
 It may be used to check for asynchronous errors on connected
 datagram sockets or for other asynchronous errors.
 the error status.
 It may be used to check for asynchronous errors on connected
 datagram sockets or for other asynchronous errors.

-.SH "RETURN VALUE"
-A 0 is returned if the call succeeds, \-1 if it fails.
-.SH ERRORS
+.Sh RETURN VALUES
+A 0 is returned if the call succeeds, -1 if it fails.
+.Sh ERRORS

 The call succeeds unless:
 The call succeeds unless:

-.TP 20
-[EBADF]
-The argument \fIs\fP is not a valid descriptor.
-.TP 20
-[ENOTSOCK]
-The argument \fIs\fP is a file, not a socket.
-.TP 20
-[ENOPROTOOPT]
+.Bl -tag -width ENOPROTOOPTAA
+.It Bq Er EBADF
+The argument
+.Fa s
+is not a valid descriptor.
+.It Bq Er ENOTSOCK
+The argument
+.Fa s
+is a file, not a socket.
+.It Bq Er ENOPROTOOPT

 The option is unknown at the level indicated.
 The option is unknown at the level indicated.

-.TP 20
-[EFAULT]
+.It Bq Er EFAULT

 The address pointed to by 
 The address pointed to by 

-.I optval
+.Fa optval

 is not in a valid part of the process address space.
 For
 is not in a valid part of the process address space.
 For

-.IR getsockopt ,
+.Fn getsockopt ,

 this error may also be returned if
 this error may also be returned if

-.I optlen
+.Fa optlen

 is not in a valid part of the process address space.
 is not in a valid part of the process address space.

-.SH "SEE ALSO"
-ioctl(2), socket(2), getprotoent(3N)
-.SH BUGS
+.El
+.Sh SEE ALSO
+.Xr ioctl 2 ,
+.Xr socket 2 ,
+.Xr getprotoent 3
+.Xr protocols 5
+.Sh BUGS

 Several of the socket options should be handled at lower levels of the system.
 Several of the socket options should be handled at lower levels of the system.

+.Sh HISTORY
+The
+.Nm
+system call appeared in
+.Bx 4.2 .