165 lines
4.9 KiB
Groff
165 lines
4.9 KiB
Groff
.\" $NetBSD: bind.2,v 1.13 1999/03/23 10:59:11 lukem Exp $
|
|
.\"
|
|
.\" Copyright (c) 1983, 1993
|
|
.\" 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.
|
|
.\"
|
|
.\" @(#)bind.2 8.1 (Berkeley) 6/4/93
|
|
.\"
|
|
.Dd March 23, 1999
|
|
.Dt BIND 2
|
|
.Os
|
|
.Sh NAME
|
|
.Nm bind
|
|
.Nd bind a name to a socket
|
|
.Sh SYNOPSIS
|
|
.Fd #include <sys/types.h>
|
|
.Fd #include <sys/socket.h>
|
|
.Ft int
|
|
.Fn bind "int s" "const struct sockaddr *name" "socklen_t namelen"
|
|
.Sh DESCRIPTION
|
|
.Fn bind
|
|
assigns a name to an unnamed socket.
|
|
When a socket is created
|
|
with
|
|
.Xr socket 2
|
|
it exists in a name space (address family)
|
|
but has no name assigned.
|
|
.Fn bind
|
|
requests that
|
|
.Fa name
|
|
be assigned to the socket.
|
|
.Sh NOTES
|
|
Binding a name in the
|
|
.Ux
|
|
domain creates a socket in the file
|
|
system that must be deleted by the caller when it is no longer
|
|
needed (using
|
|
.Xr unlink 2 ) .
|
|
.Pp
|
|
The rules used in name binding vary between communication domains.
|
|
Consult the manual entries in section 4 for detailed information.
|
|
.Sh RETURN VALUES
|
|
If the bind is successful, a 0 value is returned.
|
|
A return value of -1 indicates an error, which is
|
|
further specified in the global
|
|
.Va errno .
|
|
.Sh ERRORS
|
|
The
|
|
.Fn bind
|
|
call will fail if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EBADF
|
|
.Fa s
|
|
is not a valid descriptor.
|
|
.It Bq Er ENOTSOCK
|
|
.Fa s
|
|
is not a socket.
|
|
.It Bq Er EADDRNOTAVAIL
|
|
The specified address is not available from the local machine.
|
|
.It Bq Er EADDRINUSE
|
|
The specified address is already in use.
|
|
.It Bq Er EINVAL
|
|
The socket is already bound to an address.
|
|
.It Bq Er EACCES
|
|
The requested address is protected, and the current user
|
|
has inadequate permission to access it.
|
|
.It Bq Er EFAULT
|
|
The
|
|
.Fa name
|
|
parameter is not in a valid part of the user
|
|
address space.
|
|
.El
|
|
.Pp
|
|
The following errors are specific to binding names in the
|
|
.Ux
|
|
domain.
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOTDIR
|
|
A component of the path prefix is not a directory.
|
|
.It Bq Er ENAMETOOLONG
|
|
A component of a pathname exceeded
|
|
.Dv {NAME_MAX}
|
|
characters, or an entire path name exceeded
|
|
.Dv {PATH_MAX}
|
|
characters.
|
|
.It Bq Er ENOENT
|
|
A prefix component of the path name does not exist.
|
|
.It Bq Er ELOOP
|
|
Too many symbolic links were encountered in translating the pathname.
|
|
.It Bq Er EIO
|
|
An I/O error occurred while making the directory entry or allocating the inode.
|
|
.It Bq Er EROFS
|
|
The name would reside on a read-only file system.
|
|
.It Bq Er EISDIR
|
|
An empty pathname was specified.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr connect 2 ,
|
|
.Xr listen 2 ,
|
|
.Xr socket 2 ,
|
|
.Xr getsockname 2
|
|
.Sh HISTORY
|
|
The
|
|
.Fn bind
|
|
function call appeared in
|
|
.Bx 4.2 .
|
|
.Sh SECURITY CONSIDERATIONS
|
|
.Fn bind
|
|
was changed in
|
|
.Nx 1.4
|
|
to prevent the binding of a socket to the same port as an existing
|
|
socket when all of the following is true:
|
|
.Bl -bullet -compact -offset indent
|
|
.It
|
|
either of the existing or new addresses is
|
|
.Li INADDR_ANY ,
|
|
.It
|
|
the uid of the new socket is not root, and
|
|
the uids of the creators of the sockets are different,
|
|
.It
|
|
the address is not a multicast address, and
|
|
.It
|
|
both sockets are not bound to
|
|
.Li INADDR_ANY
|
|
with
|
|
.Li SO_REUSEPORT
|
|
set.
|
|
.El
|
|
.Pp
|
|
This prevents an attack where a user could bind to a port with
|
|
the host's IP address (after setting
|
|
.Li SO_REUSEADDR )
|
|
and
|
|
.Sq steal
|
|
packets destined for a server that bound to the
|
|
same port with
|
|
.Li INADDR_ANY .
|