link_addr							     link_addr

NAME    [Toc]    [Back]

     link_addr - elementary address specification routines for link level
     access

SYNOPSIS    [Toc]    [Back]

     #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    [Toc]    [Back]

     The routine link_addr interprets character	strings	representing linklevel
 addresses, returning	binary information suitable for	use in system
     calls.  The routine link_ntoa takes a link-level address and returns a
     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.

     For link_addr, the	string may contain an optional network interface
     identifier	of the form name unit-number, 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.

     Thus "ec0:8.0.9.13.d.30" represents an ethernet address to	be transmitted
     on	the first ethernet interface.

RETURN VALUES    [Toc]    [Back]

     link_ntoa always returns a	null terminated	string.	 link_addr has no
     return value.

BUGS    [Toc]    [Back]

     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.


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