| LINK_ADDR(3) | Library Functions Manual | LINK_ADDR(3) | 
link_addr, link_ntoa —
#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);
link_addr() interprets character strings
  representing link-level addresses, returning binary information suitable for
  use in system 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 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.
link_ntoa() always returns a null terminated string.
  link_addr() has no return value (See
  BUGS).
link_addr() and link_ntoa()
  functions appeared in 4.3BSD-Reno.
link_ntoa() resides in a static
  memory area. If it would overflow this area,
  link_ntoa() silently truncates the result.
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.
| December 7, 2016 | NetBSD 10.0 |