85 lines
1.7 KiB
Groff
85 lines
1.7 KiB
Groff
.\" @(#)bindresvport.3n 2.2 88/08/02 4.0 RPCSRC; from 1.7 88/03/14 SMI
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.\" $NetBSD: bindresvport.3,v 1.5 1998/02/05 18:49:05 perry Exp $
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.\"
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.Dd November 22, 1987
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.Dt BINDRESVPORT 3
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.Os
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.Sh NAME
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.Nm bindresvport
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.Nd bind a socket to a privileged IP port
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <netinet/in.h>
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.Ft int
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.Fn bindresvport "int sd" "struct sockaddr_in *sin"
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.Sh DESCRIPTION
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.Fn bindresvport
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is used to bind a socket descriptor to a privileged
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.Tn IP
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port, that is, a
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port number in the range 0-1023.
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The routine returns 0 if it is successful,
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otherwise -1 is returned and
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.Va errno
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set to reflect the cause of the error.
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.Pp
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If
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.Fa sin
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is a pointer to a
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.Ft "struct sockaddr_in"
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then the appropriate fields in the structure should be defined.
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If
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.Fa sin.sin_port
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is
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.Sq 0
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then an anonymous port (in the range 600-1023) will be
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chosen, and if
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.Xr bind 2
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is successful, the
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.Fa sin.sin_port
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will be updated to contain the allocated port.
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.Pp
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If
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.Fa sin
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is the
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.Dv NULL
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pointer,
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an anonymous port will be allocated (as above).
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However, there is no way for
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.Fn bindresvport
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to return the allocated port in this case.
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.Pp
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Only root can bind to a privileged port; this call will fail for any
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other users.
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.Sh RETURN VALUES
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If the bind is successful, a 0 value is returned.
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A return value of -1 indicates an error, which is
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further specified in the global
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.Va errno .
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EPFNOSUPPORT
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If
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.Fa sin
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was supplied, and
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.Fa sin.sin_family
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isn't
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.Dv AF_INET .
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.El
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.Pp
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.Fn bindresvport
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may also fail and set
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.Va errno
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for any of the errors specified for the calls
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.Xr bind 2 ,
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.Xr getsockopt 2 ,
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or
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.Xr setsockopt 2 .
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.Sh SEE ALSO
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.Xr bind 2 ,
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.Xr getsockopt 2 ,
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.Xr setsockopt 2 ,
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.Xr ip 4 .
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