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LINK_ADDR(3)		    Library Functions Manual		  LINK_ADDR(3)

NAME
       link_addr,  link_ntoa  -- elementary address specification routines for
       link level access

LIBRARY
       Standard	C Library (libc, -lc)

SYNOPSIS
       #include	<sys/types.h>
       #include	<sys/socket.h>
       #include	<net/if_dl.h>

       void
       link_addr(const char *addr, struct sockaddr_dl *sdl);

       char *
       link_ntoa(const struct sockaddr_dl *sdl);

DESCRIPTION
       The routine link_addr() interprets character strings representing link-
       level addresses,	returning binary information suitable for use in  sys-
       tem  calls.  The	routine	link_ntoa() takes a link-level address and re-
       turns an	ASCII string representing some of the information present, in-
       cluding the link	level address itself, and the interface	name  or  num-
       ber, if present.	 This facility is experimental and is still subject to
       change.

       For link_addr(),	the string addr	may contain an optional	network	inter-
       face  identifier	of the form "name unit-number",	suitable for the first
       argument	to ifconfig(8),	followed in all	cases by a colon and an	inter-
       face 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.

       Thus le0:8.0.9.13.d.30 represents an ethernet address to	be transmitted
       on the first Lance ethernet interface.

RETURN VALUES
       The link_ntoa() function	always returns a null terminated string.   The
       link_addr() function has	no return value.  (See "BUGS".)

SEE ALSO
       getnameinfo(3)

HISTORY
       The link_addr() and link_ntoa() functions appeared in 4.3BSD-Reno.

BUGS
       The returned values for link_ntoa reside	in a static memory area.

       The  function  link_addr() should diagnose improperly formed input, and
       there should be an unambiguous way to recognize this.

       If the sdl_len field of the link	socket address sdl is  0,  link_ntoa()
       will  not  insert  a colon before the interface address bytes.  If this
       translated address is given to link_addr() without inserting an initial
       colon, the latter will not interpret it correctly.

FreeBSD	13.2		       February	28, 2007		  LINK_ADDR(3)
NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUES | SEE ALSO | HISTORY | BUGS

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