LINK_ADDR(3) BSD Programmer's Manual LINK_ADDR(3)NAME
link_addr, link_ntoa - elementary address specification routines for link
level access
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 link_addr() function interprets character strings representing link-
level addresses, returning binary information suitable for use in system
calls. 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 facil-
ity 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 VALUESlink_ntoa() always returns a NUL-terminated string. link_addr() has no
return value. (See BUGS.)
SEE ALSOifconfig(8)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.
MirOS BSD #10-current July 28, 1993 1
