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 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.
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 le0:18.104.22.168.d.30 represents an ethernet address to be transmitted on the first Lance ethernet interface.
The direct use of these functions is deprecated in favor of the addr2ascii(3) interface; however, portable programs cannot rely on the latter as it is not yet widely implemented.
The link_ntoa function always returns a null terminated string. The link_addr function has no return value. (See BUGS.)