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 9.2 |