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