LINK_ADDR

Section: C Library Functions (3)
Index Return to Main Contents

BSD mandoc
BSD 4.4

NAME

link_addr link_ntoa - elementary address specification routines for link level access

SYNOPSIS

Fd #include <sys/types.h> Fd #include <sys/socket.h> Fd #include <net/if_dl.h> Ft void Fn link_addr const char *addr struct sockaddr_dl *sdl Ft char * Fn link_ntoa const struct sockaddr_dl *sdl

DESCRIPTION

The routine Fn link_addr interprets character strings representing link-level addresses, returning binary information suitable for use in system calls. The routine Fn 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 Fn link_addr , the string Fa addr may contain an optional network interface identifier of the form ``name unit-number'' suitable for the first argument to ifconfig(4), 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.

RETURN VALUES

Fn link_ntoa always returns a null terminated string. Fn link_addr has no return value. (See Sx BUGS . )

HISTORY

The Fn link_addr and Fn link_ntoa functions appeared in BSD 4.3 Reno

BUGS

The returned values for link_ntoa reside in a static memory area.

The function Fn 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 Fa sdl is 0, Fn link_ntoa will not insert a colon before the interface address bytes. If this translated address is given to Fn link_addr without inserting an initial colon, the latter will not interpret it correctly.

This document was created by man2html, using the manual pages.
Time: 19:41:59 GMT, December 25, 2022