ETHERS(3) OpenBSD Programmer's Manual ETHERS(3)NAME
ether_aton, ether_ntoa, ether_ntohost, ether_hostton, ether_line - get
ethers entry
SYNOPSIS
#include <sys/types.h>
#include <sys/socket.h>
#include <net/if.h>
#include <netinet/in.h>
#include <netinet/if_ether.h>
char *
ether_ntoa(struct ether_addr *e);
struct ether_addr *
ether_aton(const char *s);
int
ether_ntohost(char *hostname, struct ether_addr *e);
int
ether_hostton(const char *hostname, struct ether_addr *e);
int
ether_line(const char *l, struct ether_addr *e, char *hostname);
DESCRIPTION
Ethernet addresses are represented by the following structure:
struct ether_addr {
u_int8_t ether_addr_octet[6];
};
The ether_ntoa() function converts this structure into an ASCII string of
the form ``xx:xx:xx:xx:xx:xx'', consisting of 6 hexadecimal numbers
separated by colons. It returns a pointer to a static buffer that is
reused for each call. The ether_aton() converts an ASCII string of the
same form and to a structure containing the 6 octets of the address. It
returns a pointer to a static structure that is reused for each call.
ether_aton() will return NULL if the string does not represent a valid
address.
The ether_ntohost() and ether_hostton() functions interrogate the
database mapping host names to Ethernet addresses, /etc/ethers. The
ether_ntohost() function looks up the given Ethernet address and writes
the associated host name into the character buffer passed. This buffer
should be MAXHOSTNAMELEN characters in size. The ether_hostton()
function looks up the given host name and writes the associated Ethernet
address into the structure passed. Both functions return zero if they
find the requested host name or address, and -1 if not.
Each call reads /etc/ethers from the beginning; if a `+' appears alone on
a line in the file, then ether_hostton() will consult the ethers.byname
YP map, and ether_ntohost() will consult the ethers.byaddr YP map.
The ether_line() function parses a line from the /etc/ethers file and
fills in the passed struct ether_addr and character buffer with the
Ethernet address and host name on the line. It returns zero if the line
was successfully parsed and -1 if not. The character buffer should be
MAXHOSTNAMELEN characters in size.
FILES
/etc/ethers
SEE ALSOethers(5)HISTORY
The ether_ntoa(), ether_aton(), ether_ntohost(), ether_hostton(), and
ether_line() functions were adopted from SunOS and appeared in NetBSD 0.9
b.
BUGS
The data space used by these functions is static; if future use requires
the data, it should be copied before any subsequent calls to these
functions overwrite it.
OpenBSD 4.9 December 7, 2008 OpenBSD 4.9