netbsd man page for linkntoa

LINK_ADDR(3)						   BSD 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 returns an 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.

     Prior to a call to link_addr(), sdl->sdl_len must be initialized to the size of the link-level socket structure, typically sizeof(struct
     sockaddr_dl).

     For link_addr(), the string addr may contain an optional network interface identifier of the form ``name unit-number'', suitable for the
     first argument to ifconfig(8), followed in all cases by a colon and an interface address in the form of groups of hexadecimal digits sepa-
     rated 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
     link_ntoa() always returns a null terminated string.  link_addr() has no return value (See BUGS).

SEE ALSO
     ethers(3), iso(4)

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.

BSD
								   July 28, 1993							       BSD