link_addr(3c)

link_addr                                                            link_addr



NAME
     link_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.