ethers(3N)                                             ethers(3N)



     NAME
          ethers, ether_ntoa, ether_aton, ether_ntohost,
          ether_hostton,   ether_line   -   Ethernet  address  mapping
          operations

     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(e)
          struct ether_addr *e;

          struct ether_addr *ether_aton(s)
          char *s;

          ether_ntohost(hostname, e)
          char *hostname;
          struct ether_addr *e;

          ether_hostton(hostname, e)
          char *hostname;
          struct ether_addr *e;

          ether_line(l, e, hostname)
          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 correspond-
          ing host names, and vice versa.

          The function ether_ntoa converts a 48-bit Ethernet number
          pointed to by e to its standard ACSII representation; it re-
          turns 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 255.  The
          function ether_aton converts an ASCII string in the standard
          representation back to a 48-bit Ethernet number; the func-
          tion returns NULL if the string cannot be scanned success-
          fully.

          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



     April, 1990                                                     1

     ethers(3N)                                             ethers(3N)



          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 suc-
          cess and non-zero upon failure.

          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 re-
          turns zero upon success and non-zero upon failure.  The for-
          mat of the scanned line is described by ethers(4).

     FILES
          /etc/ethers
          /etc/ethers.byaddr    Yellow Pages control file
          /etc/ethers.byname    Yellow Pages control file

     SEE ALSO
          ethers(4).


































     2                                                     April, 1990