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

diff --git a/usr/src/lib/libc/sys/socket.2 b/usr/src/lib/libc/sys/socket.2
index 1e0fdd4..b9afe46 100644 (file)
--- a/usr/src/lib/libc/sys/socket.2
+++ b/usr/src/lib/libc/sys/socket.2
@@ -1,239 +1,231 @@
-.\" Copyright (c) 1983 Regents of the University of California.
-.\" All rights reserved.  The Berkeley software License Agreement
-.\" specifies the terms and conditions for redistribution.
+.\" Copyright (c) 1983, 1991 The Regents of the University of California.
+.\" All rights reserved.

 .\"
 .\"

-.\"    @(#)socket.2    6.3 (Berkeley) %G%
+.\" %sccs.include.redist.man%

 .\"
 .\"

-.TH SOCKET 2 ""
-.UC 5
-.SH NAME
-socket \- create an endpoint for communication
-.SH SYNOPSIS
-.nf
-.ft B
-#include <sys/types.h>
-#include <sys/socket.h>
-.PP
-.ft B
-s = socket(af, type, protocol)
-int s, af, type, protocol;
-.fi
-.SH DESCRIPTION
-.I Socket
+.\"     @(#)socket.2   6.8 (Berkeley) %G%
+.\"
+.Dd 
+.Dt SOCKET 2
+.Os BSD 4.2
+.Sh NAME
+.Nm socket
+.Nd create an endpoint for communication
+.Sh SYNOPSIS
+.Fd #include <sys/types.h>
+.Fd #include <sys/socket.h>
+.Ft int
+.Fn socket "int domain" "int type" "int protocol"
+.Sh DESCRIPTION
+.Fn Socket

 creates an endpoint for communication and returns a descriptor.
 creates an endpoint for communication and returns a descriptor.

-.PP
+.Pp

 The
 The

-.I af
-parameter specifies an address format with which addresses specified
-in later operations using the socket should be interpreted.  These
-formats are defined in the include file
-.IR <sys/socket.h> .
+.Fa domain
+parameter specifies a communications domain within which
+communication will take place; this selects the protocol family
+which should be used.
+These families are defined in the include file
+.Ao Pa sys/socket.h Ac .

 The currently understood formats are
 The currently understood formats are

-.PP
-.RS
-.nf
-.ta 1.25i 1.75i
-AF_UNIX        (UNIX path names),
-AF_INET        (ARPA Internet addresses),
-AF_NS  (Xerox Network Systems addresses), and
-AF_IMPLINK     (IMP \*(lqhost at IMP\*(rq addresses).
-.fi
-.RE
-.PP
+.Pp
+.Bd -literal -offset indent -compact
+AF_UNIX                (UNIX internal protocols),
+AF_INET                (ARPA Internet protocols),
+AF_ISO         (ISO protocols),
+AF_NS          (Xerox Network Systems protocols), and
+AF_IMPLINK     (IMP \*(lqhost at IMP\*(rq link layer).
+.Ed
+.Pp

 The socket has the indicated
 The socket has the indicated

-.I type,
+.Fa type ,

 which specifies the semantics of communication.  Currently
 defined types are:
 which specifies the semantics of communication.  Currently
 defined types are:

-.PP
-.RS
-.nf
+.Pp
+.Bd -literal -offset indent -compact

 SOCK_STREAM
 SOCK_DGRAM
 SOCK_RAW
 SOCK_SEQPACKET
 SOCK_RDM
 SOCK_STREAM
 SOCK_DGRAM
 SOCK_RAW
 SOCK_SEQPACKET
 SOCK_RDM

-.fi
-.RE
-.PP
-A SOCK_STREAM type provides sequenced, reliable,
-two-way connection based byte streams with an out-of-band data
-transmission mechanism.
-A SOCK_DGRAM socket supports
+.Ed
+.Pp
+A
+.Dv SOCK_STREAM
+type provides sequenced, reliable,
+two-way connection based byte streams.
+An out-of-band data transmission mechanism may be supported.
+A
+.Dv SOCK_DGRAM
+socket supports

 datagrams (connectionless, unreliable messages of
 a fixed (typically small) maximum length).
 datagrams (connectionless, unreliable messages of
 a fixed (typically small) maximum length).

-A SOCK_SEQPACKET socket may provide a sequenced, reliable,
+A
+.Dv SOCK_SEQPACKET
+socket may provide a sequenced, reliable,

 two-way connection-based data transmission path for datagrams
 of fixed maximum length; a consumer may be required to read
 an entire packet with each read system call.
 This facility is protocol specific, and presently implemented
 two-way connection-based data transmission path for datagrams
 of fixed maximum length; a consumer may be required to read
 an entire packet with each read system call.
 This facility is protocol specific, and presently implemented

-only for AF_NS.
-SOCK_RAW sockets provide access to internal network interfaces.
-The types SOCK_RAW,
+only for
+.Dv PF_NS .
+.Dv SOCK_RAW
+sockets provide access to internal network protocols and interfaces.
+The types
+.Dv SOCK_RAW ,

 which is available only to the super-user, and
 which is available only to the super-user, and

-SOCK_RDM, which is planned,
+.Dv SOCK_RDM ,
+which is planned,

 but not yet implemented, are not described here.
 but not yet implemented, are not described here.

-.PP
+.Pp

 The
 The

-.I protocol
+.Fa protocol

 specifies a particular protocol to be used with the socket.
 Normally only a single protocol exists to support a particular
 specifies a particular protocol to be used with the socket.
 Normally only a single protocol exists to support a particular

-socket type using a given address format.  However, it is possible
-that many protocols may exist in which case a particular protocol
+socket type within a given protocol family.  However, it is possible
+that many protocols may exist, in which case a particular protocol

 must be specified in this manner.  The protocol number to use is
 particular to the \*(lqcommunication domain\*(rq in which communication
 is to take place; see
 must be specified in this manner.  The protocol number to use is
 particular to the \*(lqcommunication domain\*(rq in which communication
 is to take place; see

-.IR services (3N)
-and
-.IR protocols (3N).
-.PP
-Sockets of type SOCK_STREAM
+.Xr protocols 5 .
+.Pp
+Sockets of type
+.Dv SOCK_STREAM

 are full-duplex byte streams, similar
 to pipes.  A stream socket must be in a
 are full-duplex byte streams, similar
 to pipes.  A stream socket must be in a

-.I connected
+.Em connected

 state before any data may be sent or received
 on it.  A connection to another socket is created with a
 state before any data may be sent or received
 on it.  A connection to another socket is created with a

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

 call.  Once connected, data may be transferred using
 call.  Once connected, data may be transferred using

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

 and
 and

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

 calls or some variant of the 
 calls or some variant of the 

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

 and
 and

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

 calls.  When a session has been completed a
 calls.  When a session has been completed a

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

 may be performed.
 Out-of-band data may also be transmitted as described in
 may be performed.
 Out-of-band data may also be transmitted as described in

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

 and received as described in
 and received as described in

-.IR recv (2).
-.PP
+.Xr recv 2 .
+.Pp

 The communications protocols used to implement a
 The communications protocols used to implement a

-SOCK_STREAM insure that data
+.Dv SOCK_STREAM
+insure that data

 is not lost or duplicated.  If a piece of data for which the
 peer protocol has buffer space cannot be successfully transmitted
 within a reasonable length of time, then
 the connection is considered broken and calls
 will indicate an error with
 is not lost or duplicated.  If a piece of data for which the
 peer protocol has buffer space cannot be successfully transmitted
 within a reasonable length of time, then
 the connection is considered broken and calls
 will indicate an error with

-\-1 returns and with ETIMEDOUT as the specific code
-in the global variable errno.
-The protocols optionally keep sockets \*(lqwarm\*(rq by
-forcing transmissions
+-1 returns and with
+.Dv ETIMEDOUT
+as the specific code
+in the global variable
+.Va errno .
+The protocols optionally keep sockets
+.Dq warm
+by forcing transmissions

 roughly every minute in the absence of other activity.
 An error is then indicated if no response can be
 elicited on an otherwise
 idle connection for a extended period (e.g. 5 minutes).
 roughly every minute in the absence of other activity.
 An error is then indicated if no response can be
 elicited on an otherwise
 idle connection for a extended period (e.g. 5 minutes).

-A SIGPIPE signal is raised if a process sends
+A
+.Dv SIGPIPE
+signal is raised if a process sends

 on a broken stream; this causes naive processes,
 which do not handle the signal, to exit.
 on a broken stream; this causes naive processes,
 which do not handle the signal, to exit.

-.PP
-SOCK_SEQPACKET sockets employ the same system calls
-as SOCK_STREAM sockets.  The only difference
+.Pp
+.Dv SOCK_SEQPACKET
+sockets employ the same system calls
+as
+.Dv SOCK_STREAM
+sockets.  The only difference

 is that 
 is that 

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

 calls will return only the amount of data requested,
 and any remaining in the arriving packet will be discarded.
 calls will return only the amount of data requested,
 and any remaining in the arriving packet will be discarded.

-.PP
-SOCK_DGRAM and SOCK_RAW
+.Pp
+.Dv SOCK_DGRAM
+and
+.Dv SOCK_RAW

 sockets allow sending of datagrams to correspondents
 named in
 sockets allow sending of datagrams to correspondents
 named in

-.IR send (2)
-calls.  It is also possible to receive datagrams at
-such a socket with
-.IR recv (2).
-.PP
+.Xr send 2
+calls.  Datagrams are generally received with
+.Xr recvfrom 2 ,
+which returns the next datagram with its return address.
+.Pp

 An 
 An 

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

 call can be used to specify a process group to receive
 call can be used to specify a process group to receive

-a SIGURG signal when the out-of-band data arrives.
-.PP
+a
+.Dv SIGURG
+signal when the out-of-band data arrives.
+It may also enable non-blocking I/O
+and asynchronous notification of I/O events
+via
+.Dv SIGIO .
+.Pp

 The operation of sockets is controlled by socket level
 The operation of sockets is controlled by socket level

-.IR options .
+.Em options .

 These options are defined in the file
 These options are defined in the file

-.RI < sys/socket.h >
-and explained below.  
-.I Setsockopt
+.Ao Pa sys/socket.h Ac .
+.Xr Setsockopt 2

 and
 and

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

 are used to set and get options, respectively.
 are used to set and get options, respectively.

-Options other than SO_LINGER take an 
-.I int
-parameter, which should non-zero if the option is to be
-enabled, or zero if it is to be disabled; SO_LINGER
-uses a
-.I struct linger
-parameter, defined in
-.RI < sys/socket.h >,
-which specifies the desired state of the option and the
-linger interval (see below).
-.PP
-.RS
-.DT
-.nf
-SO_DEBUG               turn on recording of debugging information
-SO_REUSEADDR   allow local address reuse
-SO_KEEPALIVE   keep connections alive
-SO_DONTROUTE   do not route outgoing messages
-SO_LINGER      linger on close if data present
-SO_BROADCAST   permit transmission of broadcast messages
-.fi
-.RE
-.PP
-SO_DEBUG enables debugging in the underlying protocol modules.
-SO_REUSEADDR indicates the rules used in validating addresses supplied
-in a
-.IR bind (2)
-call should allow reuse of local addresses.  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
-SIGPIPE signal.  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.  SO_LINGER
-controls the action taken when unsent messags
-are queued on socket and a 
-.IR close (2)
-is performed.
-If the socket promises reliable delivery of data and SO_LINGER is set,
-the system will block the process on the 
-.I 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
-.IR setsockopt 
-call when SO_LINGER is requested). 
-If SO_LINGER is disabled and a 
-.I close
-is issued, the system will process the close in a manner that allows
-the process to continue as quickly as possible.
-.SH "RETURN VALUE
-A \-1 is returned if an error occurs, otherwise the return
+.Sh RETURN VALUES
+A -1 is returned if an error occurs, otherwise the return

 value is a descriptor referencing the socket.
 value is a descriptor referencing the socket.

-.SH "ERRORS
-The \fIsocket\fP call fails if:
-.TP 20
-[EAFNOSUPPORT]
-The specified address family is not supported in this version
-of the system.
-.TP 20
-[ESOCKTNOSUPPORT]
-The specified socket type is not supported in this address family.
-.TP 20
-[EPROTONOSUPPORT]
-The specified protocol is not supported.
-.TP 20
-[EMFILE]
+.Sh ERRORS
+The
+.Fn socket
+call fails if:
+.Bl -tag -width EPROTONOPSUPPORTA
+.It Bq Er EPROTONOSUPPORT
+The protocol type or the specified protocol is not supported
+within this domain.
+.It Bq Er EMFILE

 The per-process descriptor table is full.
 The per-process descriptor table is full.

-.TP 20
-[ENOBUFS]
-No buffer space is available.  The socket cannot be created.
-.SH SEE ALSO
-accept(2), bind(2), connect(2), getsockname(2), getsockopt(2),
-ioctl(2), listen(2), recv(2),
-select(2), send(2), shutdown(2), socketpair(2)
-.br
-``A 4.2BSD Interprocess Communication Primer''.
-.SH BUGS
-The use of keepalives is a questionable feature for this layer.
+.It Bq Er ENFILE
+The system file table is full.
+.It Bq Er EACCESS
+Permission to create a socket of the specified type and/or protocol
+is denied.
+.It Bq Er ENOBUFS
+Insufficient buffer space is available.
+The socket cannot be created until sufficient resources are freed.
+.El
+.Sh SEE ALSO
+.Xr accept 2 ,
+.Xr bind 2 ,
+.Xr connect 2 ,
+.Xr getprotoent 3 ,
+.Xr getsockname 2 ,
+.Xr getsockopt 2 ,
+.Xr ioctl 2 ,
+.Xr listen 2 ,
+.Xr read 2 ,
+.Xr recv 2 ,
+.Xr select 2 ,
+.Xr send 2 ,
+.Xr shutdown 2 ,
+.Xr socketpair 2 ,
+.Xr write 2
+.Rs
+.%T "An Introductory 4.3 BSD Interprocess Communication Tutorial"
+.%O "reprinted in UNIX Programmer's Supplementary Documents Volume 1"
+.Re
+.Rs
+.%T "BSD Interprocess Communication Tutorial"
+.%O "reprinted in UNIX Programmer's Supplementary Documents Volume 1"
+.Re
+.Sh HISTORY
+The
+.Nm
+function call appeared in
+.Bx 4.2 .