1130b656e5
This will make a number of things easier in the future, as well as (finally!) avoiding the Id-smashing problem which has plagued developers for so long. Boy, I'm glad we're not using sup anymore. This update would have been insane otherwise.
185 lines
5.0 KiB
Groff
185 lines
5.0 KiB
Groff
.\" Copyright (c) 1995
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.\" Bill Paul <wpaul@ctr.columbia.edu>. All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by Bill Paul.
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.\" 4. Neither the name of the author nor the names of any co-contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY Bill Paul AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 12, 1995
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.Dt ETHERS 3
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.Os FreeBSD 2.1
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.Sh NAME
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.Nm ethers ,
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.Nm ether_line ,
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.Nm ether_aton ,
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.Nm ether_ntoa ,
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.Nm ether_ntohost ,
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.Nm ether_hostton
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.Nd Ethernet address conversion and lookup routines
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <sys/socket.h>
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.Fd #include <net/ethernet.h>
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.Ft int
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.Fn ether_line "char *l" "struct ether_addr *e" "char *hostname"
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.Ft struct ether_addr *
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.Fn ether_aton "char *a"
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.Ft char *
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.Fn ether_ntoa "struct ether_addr *n"
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.Ft int
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.Fn ether_ntohost "char *hostname" "struct ether_addr *e"
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.Ft int
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.Fn ether_hostton "char *hostname" "struct ether_addr *e"
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.Sh DESCRIPTION
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These functions operate on ethernet addresses using an
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.Ar ether_addr
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structure, which is defined in the header file
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.Aq Pa netinet/if_ether.h :
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.Bd -literal -offset indent
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/*
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* Structure of a 48-bit Ethernet address.
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*/
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struct ether_addr {
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u_char octet[6];
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};
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.Ed
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.Pp
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The function
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.Fn ether_line
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scans
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.Ar l ,
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an
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.Tn ASCII
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string in
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.Xr ethers 5
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format and sets
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.Ar e
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to the ethernet address specified in the string and
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.Ar h
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to the hostname. This function is used to parse lines from
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.Pa /etc/ethers
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into their component parts.
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.Pp
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The
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.Fn ether_aton
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function converts an
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.Tn ASCII
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representation of an ethernet address into an
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.Ar ether_addr
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structure. Likewise,
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.Fn ether_ntoa
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converts an ethernet address specified as an
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.Ar ether_addr
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structure into an
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.Tn ASCII
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string.
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.Pp
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The
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.Fn ether_ntohost
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and
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.Fn ether_hostton
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functions map ethernet addresses to their corresponding hostnames
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as specified in the
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.Pa /etc/ethers
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database.
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.Fn ether_ntohost
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converts from ethernet address to hostname, and
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.Fn ether_hostton
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converts from hostname to ethernet address.
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.Sh RETURN VALUES
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.Fn ether_line
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returns zero on success and non-zero if it was unable to parse
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any part of the supplied line
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.Ar l .
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It returns the extracted ethernet address in the supplied
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.Ar ether_addr
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structure
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.Ar e
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and the hostname in the supplied string
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.Ar h .
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.Pp
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On success,
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.Fn ether_ntoa
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returns a pointer to a string containing an
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.Tn ASCII
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representation of an ethernet address. If it is unable to convert
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the supplied
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.Ar ether_addr
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structure, it returns a NULL pointer. Likewise,
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.Fn ether_aton
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returns a pointer to an
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.Ar ether_addr
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structure on success and a NULL pointer on failure.
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.Pp
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The
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.Fn ether_ntohost
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and
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.Fn ether_hostton
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functions both return zero on success or non-zero if they were
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unable to find a match in the
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.Pa /etc/ethers
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database.
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.Sh NOTES
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The user must insure that the hostname strings passed to the
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the
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.Fn ether_line ,
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.Fn ether_ntohost
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and
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.Fn ether_hostton
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functions are large enough to contain the returned hostnames.
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.Sh NIS INTERACTION
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If the
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.Pa /etc/ethers
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contains a line with a single + in it, the
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.Fn ether_ntohost
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and
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.Fn ether_hostton
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functions will attempt to consult the NIS
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.Pa ethers.byname
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and
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.Pa ethers.byaddr
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maps in addition to the data in the
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.Pa /etc/ethers
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file.
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.Sh SEE ALSO
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.Xr yp 4 ,
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.Xr ethers 5
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.Sh BUGS
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.Pp
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The
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.Fn ether_aton
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and
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.Fn ether_ntoa
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functions returns values that are stored in static memory areas
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which may be overwritten the next time they are called.
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.Sh HISTORY
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This particular implementation of the
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.Nm ethers
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library functions were written for and first appeared in
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.Fx 2.1 .
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