62ad77f006
passed storage buffers rather than using static storage. Reimplement ether_ntoa() and ether_aton() in terms of these functions. These variants are thread-safe.
235 lines
5.9 KiB
Groff
235 lines
5.9 KiB
Groff
.\" Copyright (c) 1995 Bill Paul <wpaul@ctr.columbia.edu>.
|
|
.\" Copyright (c) 2007 Robert N. M. Watson
|
|
.\" 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 Bill Paul.
|
|
.\" 4. Neither the name of the author nor the names of any co-contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY Bill Paul 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.
|
|
.\"
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd May 13, 2007
|
|
.Dt ETHERS 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm ethers ,
|
|
.Nm ether_line ,
|
|
.Nm ether_aton ,
|
|
.Nm ether_aton_r ,
|
|
.Nm ether_ntoa ,
|
|
.Nm ether_ntoa_r ,
|
|
.Nm ether_ntohost ,
|
|
.Nm ether_hostton
|
|
.Nd Ethernet address conversion and lookup routines
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In sys/socket.h
|
|
.In net/ethernet.h
|
|
.Ft int
|
|
.Fn ether_line "const char *l" "struct ether_addr *e" "char *hostname"
|
|
.Ft struct ether_addr *
|
|
.Fn ether_aton "const char *a"
|
|
.Ft struct ether_addr *
|
|
.Fn ether_aton_r "const char *a" "struct ether_addr *e"
|
|
.Ft char *
|
|
.Fn ether_ntoa "const struct ether_addr *n"
|
|
.Ft char *
|
|
.Fn ether_ntoa_r "const struct ether_addr *n" "char *buf"
|
|
.Ft int
|
|
.Fn ether_ntohost "char *hostname" "const struct ether_addr *e"
|
|
.Ft int
|
|
.Fn ether_hostton "const char *hostname" "struct ether_addr *e"
|
|
.Sh DESCRIPTION
|
|
These functions operate on ethernet addresses using an
|
|
.Vt ether_addr
|
|
structure, which is defined in the header file
|
|
.In netinet/if_ether.h :
|
|
.Bd -literal -offset indent
|
|
/*
|
|
* The number of bytes in an ethernet (MAC) address.
|
|
*/
|
|
#define ETHER_ADDR_LEN 6
|
|
|
|
/*
|
|
* Structure of a 48-bit Ethernet address.
|
|
*/
|
|
struct ether_addr {
|
|
u_char octet[ETHER_ADDR_LEN];
|
|
};
|
|
.Ed
|
|
.Pp
|
|
The function
|
|
.Fn ether_line
|
|
scans
|
|
.Fa l ,
|
|
an
|
|
.Tn ASCII
|
|
string in
|
|
.Xr ethers 5
|
|
format and sets
|
|
.Fa e
|
|
to the ethernet address specified in the string and
|
|
.Fa h
|
|
to the hostname.
|
|
This function is used to parse lines from
|
|
.Pa /etc/ethers
|
|
into their component parts.
|
|
.Pp
|
|
The
|
|
.Fn ether_aton
|
|
and
|
|
.Fn ether_aton_r
|
|
functions convert
|
|
.Tn ASCII
|
|
representation of ethernet addresses into
|
|
.Vt ether_addr
|
|
structures.
|
|
Likewise, the
|
|
.Fn ether_ntoa
|
|
and
|
|
.Fn ether_ntoa_r
|
|
functions
|
|
convert ethernet addresses specified as
|
|
.Vt ether_addr
|
|
structures into
|
|
.Tn ASCII
|
|
strings.
|
|
.Pp
|
|
The
|
|
.Fn ether_ntohost
|
|
and
|
|
.Fn ether_hostton
|
|
functions map ethernet addresses to their corresponding hostnames
|
|
as specified in the
|
|
.Pa /etc/ethers
|
|
database.
|
|
The
|
|
.Fn ether_ntohost
|
|
function
|
|
converts from ethernet address to hostname, and
|
|
.Fn ether_hostton
|
|
converts from hostname to ethernet address.
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn ether_line
|
|
function
|
|
returns zero on success and non-zero if it was unable to parse
|
|
any part of the supplied line
|
|
.Fa l .
|
|
It returns the extracted ethernet address in the supplied
|
|
.Vt ether_addr
|
|
structure
|
|
.Fa e
|
|
and the hostname in the supplied string
|
|
.Fa h .
|
|
.Pp
|
|
On success,
|
|
.Fn ether_ntoa
|
|
and
|
|
.Fn ether_ntoa_r
|
|
functions return a pointer to a string containing an
|
|
.Tn ASCII
|
|
representation of an ethernet address.
|
|
If it is unable to convert
|
|
the supplied
|
|
.Vt ether_addr
|
|
structure, it returns a
|
|
.Dv NULL
|
|
pointer.
|
|
.Fn ether_ntoa
|
|
stores the result in a static buffer;
|
|
.Fn ether_ntoa_r
|
|
stores the result in a user-passed buffer.
|
|
.Pp
|
|
|
|
Likewise,
|
|
.Fn ether_aton
|
|
and
|
|
.Fn ether_aton_r
|
|
return a pointer to an
|
|
.Vt ether_addr
|
|
structure on success and a
|
|
.Dv NULL
|
|
pointer on failure.
|
|
.Fn ether_aton
|
|
stores the result in a static buffer;
|
|
.Fn ether_aton_r
|
|
stores the result in a user-passed buffer.
|
|
.Pp
|
|
The
|
|
.Fn ether_ntohost
|
|
and
|
|
.Fn ether_hostton
|
|
functions both return zero on success or non-zero if they were
|
|
unable to find a match in the
|
|
.Pa /etc/ethers
|
|
database.
|
|
.Sh NOTES
|
|
The user must insure that the hostname strings passed to the
|
|
.Fn ether_line ,
|
|
.Fn ether_ntohost
|
|
and
|
|
.Fn ether_hostton
|
|
functions are large enough to contain the returned hostnames.
|
|
.Sh NIS INTERACTION
|
|
If the
|
|
.Pa /etc/ethers
|
|
contains a line with a single + in it, the
|
|
.Fn ether_ntohost
|
|
and
|
|
.Fn ether_hostton
|
|
functions will attempt to consult the NIS
|
|
.Pa ethers.byname
|
|
and
|
|
.Pa ethers.byaddr
|
|
maps in addition to the data in the
|
|
.Pa /etc/ethers
|
|
file.
|
|
.Sh SEE ALSO
|
|
.Xr ethers 5 ,
|
|
.Xr yp 8
|
|
.Sh HISTORY
|
|
This particular implementation of the
|
|
.Nm
|
|
library functions were written for and first appeared in
|
|
.Fx 2.1 .
|
|
Thread-safe function variants first appeared in
|
|
.Fx 7.0 .
|
|
.Sh BUGS
|
|
The
|
|
.Fn ether_aton
|
|
and
|
|
.Fn ether_ntoa
|
|
functions returns values that are stored in static memory areas
|
|
which may be overwritten the next time they are called.
|
|
.Pp
|
|
.Fn ether_ntoa_r
|
|
accepts a character buffer pointer, but not a buffer length.
|
|
The caller must ensure adequate space is available in the buffer in order to
|
|
avoid a buffer overflow.
|