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. 15.\" 3. All advertising materials mentioning features or use of this software 16.\" must display the following acknowledgement: 17.\" This product includes software developed by the University of 18.\" California, Berkeley and its contributors. 19.\" 4. Neither the name of the University nor the names of its contributors 20.\" may be used to endorse or promote products derived from this software 21.\" without specific prior written permission. 22.\" 23.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 24.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 25.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 26.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 27.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 28.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 29.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 30.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 31.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 32.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 33.\" SUCH DAMAGE. 34.\" 35.\" From: @(#)linkaddr.3 8.1 (Berkeley) 7/28/93 36.\" $Id$ 37.\" 38.Dd June 17, 1996 39.Dt LINK_ADDR 3 40.Os BSD 4.4 41.Sh NAME 42.Nm link_addr , 43.Nm link_ntoa 44.Nd elementary address specification routines for link level access 45.Sh SYNOPSIS 46.Fd #include <sys/types.h> 47.Fd #include <sys/socket.h> 48.Fd #include <net/if_dl.h> 49.Ft void 50.Fn link_addr "const char *addr" "struct sockaddr_dl *sdl" 51.Ft char * 52.Fn link_ntoa "const struct sockaddr_dl *sdl" 53.Sh DESCRIPTION 54The routine 55.Fn link_addr 56interprets character strings representing 57link-level addresses, returning binary information suitable 58for use in system calls. 59The routine 60.Fn link_ntoa 61takes 62a link-level 63address and returns an 64.Tn ASCII 65string representing some of the information present, 66including the link level address itself, and the interface name 67or number, if present. 68This facility is experimental and is 69still subject to change. 70.Pp 71For 72.Fn link_addr , 73the string 74.Fa addr 75may contain 76an optional network interface identifier of the form 77.Dq "name unit-number" , 78suitable for the first argument to 79.Xr ifconfig 8 , 80followed in all cases by a colon and 81an interface address in the form of 82groups of hexadecimal digits 83separated by periods. 84Each group represents a byte of address; 85address bytes are filled left to right from 86low order bytes through high order bytes. 87.Pp 88.\" A regular expression may make this format clearer: 89.\" .Bd -literal -offset indent 90.\" ([a-z]+[0-9]+:)?[0-9a-f]+(\e.[0-9a-f]+)* 91.\" .Ed 92.\" .Pp 93Thus 94.Li le0:8.0.9.13.d.30 95represents an ethernet address 96to be transmitted on the first Lance ethernet interface. 97.Pp 98The direct use of these functions is deprecated in favor of the 99.Xr addr2ascii 3 100interface; however, portable programs cannot rely on the latter as it is 101not yet widely implemented. 102.Sh RETURN VALUES 103.Fn link_ntoa 104always returns a null terminated string. 105.Fn link_addr 106has no return value. 107(See 108.Sx BUGS . ) 109.Sh SEE ALSO 110.Xr addr2ascii 3 111.\" .Xr iso 4 112.Sh HISTORY 113The 114.Fn link_addr 115and 116.Fn link_ntoa 117functions appeared in 118.Bx 4.3 Reno . 119.Sh BUGS 120The returned values for link_ntoa 121reside in a static memory area. 122.Pp 123The function 124.Fn link_addr 125should diagnose improperly formed input, and there should be an unambiguous 126way to recognize this. 127.Pp 128If the 129.Va sdl_len 130field of the link socket address 131.Fa sdl 132is 0, 133.Fn link_ntoa 134will not insert a colon before the interface address bytes. 135If this translated address is given to 136.Fn link_addr 137without inserting an initial colon, 138the latter will not interpret it correctly. 139