[dragonfly.git] / lib / libc / net / linkaddr.3

.\" Copyright (c) 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Donn Seeley at BSDI.
.\"
.\" 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.
.\" 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.
.\"
.\"     From: @(#)linkaddr.3	8.1 (Berkeley) 7/28/93
.\" $FreeBSD: src/lib/libc/net/linkaddr.3,v 1.16 2007/02/28 21:18:38 bms Exp $
.\"
.Dd February 28, 2007
.Dt LINK_ADDR 3
.Os
.Sh NAME
.Nm link_addr ,
.Nm link_ntoa
.Nd elementary address specification routines for link level access
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In sys/types.h
.In sys/socket.h
.In net/if_dl.h
.Ft void
.Fn link_addr "const char *addr" "struct sockaddr_dl *sdl"
.Ft char *
.Fn link_ntoa "const struct sockaddr_dl *sdl"
.Sh DESCRIPTION
The routine
.Fn link_addr
interprets character strings representing
link-level addresses, returning binary information suitable
for use in system calls.
The routine
.Fn link_ntoa
takes
a link-level
address and returns an
.Tn ASCII
string representing some of the information present,
including the link level address itself, and the interface name
or number, if present.
This facility is experimental and is
still subject to change.
.Pp
For
.Fn link_addr ,
the string
.Fa addr
may contain
an optional network interface identifier of the form
.Dq "name unit-number" ,
suitable for the first argument to
.Xr ifconfig 8 ,
followed in all cases by a colon and
an interface address in the form of
groups of hexadecimal digits
separated by periods.
Each group represents a byte of address;
address bytes are filled left to right from
low order bytes through high order bytes.
.Pp
.\" A regular expression may make this format clearer:
.\" .Bd -literal -offset indent
.\" ([a-z]+[0-9]+:)?[0-9a-f]+(\e.[0-9a-f]+)*
.\" .Ed
.\" .Pp
Thus
.Li lnc0:8.0.9.13.d.30
represents an ethernet address
to be transmitted on the first Lance ethernet interface.
.Sh RETURN VALUES
The
.Fn link_ntoa
function
always returns a null terminated string.
The
.Fn link_addr
function
has no return value.
(See
.Sx BUGS . )
.Sh SEE ALSO
.Xr getnameinfo 3
.Sh HISTORY
The
.Fn link_addr
and
.Fn link_ntoa
functions appeared in
.Bx 4.3 Reno .
.Sh BUGS
The returned values for
.Fn link_ntoa
reside in a static memory area.
.Pp
The function
.Fn link_addr
should diagnose improperly formed input, and there should be an unambiguous
way to recognize this.
.Pp
If the
.Va sdl_len
field of the link socket address
.Fa sdl
is 0,
.Fn link_ntoa
will not insert a colon before the interface address bytes.
If this translated address is given to
.Fn link_addr
without inserting an initial colon,
the latter will not interpret it correctly.
Commit	Line	Data
984263bc MD	1	.\" Copyright (c) 1993
	2	.\" The Regents of the University of California. All rights reserved.
	3	.\"
	4	.\" This code is derived from software contributed to Berkeley by
	5	.\" Donn Seeley at BSDI.
	6	.\"
	7	.\" Redistribution and use in source and binary forms, with or without
	8	.\" modification, are permitted provided that the following conditions
	9	.\" are met:
	10	.\" 1. Redistributions of source code must retain the above copyright
	11	.\" notice, this list of conditions and the following disclaimer.
	12	.\" 2. Redistributions in binary form must reproduce the above copyright
	13	.\" notice, this list of conditions and the following disclaimer in the
	14	.\" documentation and/or other materials provided with the distribution.
984263bc MD	15	.\" 4. Neither the name of the University nor the names of its contributors
	16	.\" may be used to endorse or promote products derived from this software
	17	.\" without specific prior written permission.
	18	.\"
	19	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	20	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	21	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	22	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	23	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	24	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	25	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	26	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	27	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	28	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	29	.\" SUCH DAMAGE.
	30	.\"
	31	.\" From: @(#)linkaddr.3 8.1 (Berkeley) 7/28/93
12b71966	32	.\" $FreeBSD: src/lib/libc/net/linkaddr.3,v 1.16 2007/02/28 21:18:38 bms Exp $
984263bc	33	.\"
12b71966	34	.Dd February 28, 2007
984263bc MD	35	.Dt LINK_ADDR 3
	36	.Os
	37	.Sh NAME
	38	.Nm link_addr ,
	39	.Nm link_ntoa
	40	.Nd elementary address specification routines for link level access
	41	.Sh LIBRARY
	42	.Lb libc
	43	.Sh SYNOPSIS
	44	.In sys/types.h
	45	.In sys/socket.h
	46	.In net/if_dl.h
	47	.Ft void
	48	.Fn link_addr "const char addr" "struct sockaddr_dl sdl"
	49	.Ft char *
	50	.Fn link_ntoa "const struct sockaddr_dl *sdl"
	51	.Sh DESCRIPTION
	52	The routine
	53	.Fn link_addr
	54	interprets character strings representing
	55	link-level addresses, returning binary information suitable
	56	for use in system calls.
	57	The routine
	58	.Fn link_ntoa
	59	takes
	60	a link-level
	61	address and returns an
	62	.Tn ASCII
	63	string representing some of the information present,
	64	including the link level address itself, and the interface name
	65	or number, if present.
	66	This facility is experimental and is
	67	still subject to change.
	68	.Pp
	69	For
	70	.Fn link_addr ,
	71	the string
	72	.Fa addr
	73	may contain
	74	an optional network interface identifier of the form
	75	.Dq "name unit-number" ,
	76	suitable for the first argument to
	77	.Xr ifconfig 8 ,
	78	followed in all cases by a colon and
	79	an interface address in the form of
	80	groups of hexadecimal digits
	81	separated by periods.
	82	Each group represents a byte of address;
	83	address bytes are filled left to right from
	84	low order bytes through high order bytes.
	85	.Pp
	86	.\" A regular expression may make this format clearer:
	87	.\" .Bd -literal -offset indent
	88	.\" ([a-z]+[0-9]+:)?[0-9a-f]+(\e.[0-9a-f]+)*
	89	.\" .Ed
	90	.\" .Pp
	91	Thus
ad9f8794	92	.Li lnc0:8.0.9.13.d.30
984263bc MD	93	represents an ethernet address
984263bc MD	94	to be transmitted on the first Lance ethernet interface.
984263bc	95	.Sh RETURN VALUES
12b71966	96	The
984263bc	97	.Fn link_ntoa
12b71966	98	function
984263bc	99	always returns a null terminated string.
12b71966	100	The
984263bc	101	.Fn link_addr
12b71966	102	function
984263bc MD	103	has no return value.
	104	(See
	105	.Sx BUGS . )
	106	.Sh SEE ALSO
12b71966	107	.Xr getnameinfo 3
984263bc MD	108	.Sh HISTORY
	109	The
	110	.Fn link_addr
	111	and
	112	.Fn link_ntoa
	113	functions appeared in
12b71966	114	.Bx 4.3 Reno .
984263bc	115	.Sh BUGS
3efc72a7 SW	116	The returned values for
3efc72a7 SW	117	.Fn link_ntoa
984263bc MD	118	reside in a static memory area.
	119	.Pp
	120	The function
	121	.Fn link_addr
	122	should diagnose improperly formed input, and there should be an unambiguous
	123	way to recognize this.
	124	.Pp
	125	If the
	126	.Va sdl_len
	127	field of the link socket address
	128	.Fa sdl
	129	is 0,
	130	.Fn link_ntoa
	131	will not insert a colon before the interface address bytes.
	132	If this translated address is given to
	133	.Fn link_addr
	134	without inserting an initial colon,
	135	the latter will not interpret it correctly.