ETHERS(3SOCKET)ETHERS(3SOCKET)NAME
ethers, ether_ntoa, ether_aton, ether_ntohost, ether_hostton,
ether_line - Ethernet address mapping operations
SYNOPSIS
cc [ flag ... ] file ... -lsocket-lnsl [ library ... ]
#include <sys/types.h>
#include <sys/ethernet.h>
char *ether_ntoa(const struct ether_addr *e);
struct ether_addr *ether_aton(const char *s);
int ether_ntohost(char *hostname, const 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
These routines are useful for mapping 48 bit Ethernet numbers to their
ASCII representations or their corresponding host names, and vice
versa.
The function ether_ntoa() converts a 48 bit Ethernet number pointed to
by e to its standard ASCII representation; it returns a pointer to the
ASCII string. The representation is of the form x:x:x: x:x:x where x
is a hexadecimal number between 0 and ff. The function ether_aton()
converts an ASCII string in the standard representation back to a 48
bit Ethernet number; the function returns NULL if the string cannot be
scanned successfully.
The function ether_ntohost() maps an Ethernet number (pointed to by e)
to its associated hostname. The string pointed to by hostname must be
long enough to hold the hostname and a NULL character. The function
returns zero upon success and non-zero upon failure. Inversely, the
function ether_hostton() maps a hostname string to its corresponding
Ethernet number; the function modifies the Ethernet number pointed to
by e. The function also returns zero upon success and non-zero upon
failure. In order to do the mapping, both these functions may lookup
one or more of the following sources: the ethers file, the NIS maps
ethers.byname and ethers.byaddr and the NIS+ table ethers. The sources
and their lookup order are specified in the /etc/nsswitch.conf file.
See nsswitch.conf(4) for details.
The function ether_line() scans a line, pointed to by l, and sets the
hostname and the Ethernet number, pointed to by e. The string pointed
to by hostname must be long enough to hold the hostname and a NULL
character. The function returns zero upon success and non-zero upon
failure. The format of the scanned line is described by ethers(4).
FILES
/etc/ethers
Ethernet address to hostname database or domain
/etc/nsswitch.conf
configuration file for the name service switch
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌───────────────┬─────────────────┐
│ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├───────────────┼─────────────────┤
│MT-Level │ MT-Safe │
└───────────────┴─────────────────┘
SEE ALSOethers(4), nsswitch.conf(4), attributes(5)
Apr 5, 2004 ETHERS(3SOCKET)
