NAME

       ether_aton,  ether_ntoa,  ether_ntohost, ether_hostton, ether_line, ether_ntoa_r, ether_aton_r - Ethernet
       address manipulation routines

SYNOPSIS

       #include <netinet/ether.h>

       char *ether_ntoa(const struct ether_addr *addr);

       struct ether_addr *ether_aton(const char *asc);

       int ether_ntohost(char *hostname, const struct ether_addr *addr);

       int ether_hostton(const char *hostname, struct ether_addr *addr);

       int ether_line(const char *line, struct ether_addr *addr,
                      char *hostname);

       /* GNU extensions */
       char *ether_ntoa_r(const struct ether_addr *addr, char *buf);

       struct ether_addr *ether_aton_r(const char *asc,
                                       struct ether_addr *addr);

DESCRIPTION

       ether_aton() converts the 48-bit Ethernet  host  address  asc  from  the  standard  hex-digits-and-colons
       notation  into  binary  data  in network byte order and returns a pointer to it in a statically allocated
       buffer, which subsequent calls will overwrite.  ether_aton() returns NULL if the address is invalid.

       The ether_ntoa() function converts the Ethernet host address addr given in network byte order to a string
       in  standard  hex-digits-and-colons  notation,  omitting  leading  zeros.   The  string  is returned in a
       statically allocated buffer, which subsequent calls will overwrite.

       The ether_ntohost() function maps an Ethernet address to the corresponding hostname  in  /etc/ethers  and
       returns nonzero if it cannot be found.

       The  ether_hostton()  function  maps  a hostname to the corresponding Ethernet address in /etc/ethers and
       returns nonzero if it cannot be found.

       The ether_line() function parses a line in /etc/ethers format (ethernet address  followed  by  whitespace
       followed  by  hostname; '#' introduces a comment) and returns an address and hostname pair, or nonzero if
       it cannot be parsed.  The buffer pointed to by hostname must be sufficiently long, for example, have  the
       same length as line.

       The  functions  ether_ntoa_r()  and ether_aton_r() are reentrant thread-safe versions of ether_ntoa() and
       ether_aton() respectively, and do not use static buffers.

       The structure ether_addr is defined in <net/ethernet.h> as:

           struct ether_addr {
               uint8_t ether_addr_octet[6];
           }

ATTRIBUTES

   Multithreading (see pthreads(7))
       The ether_aton() and ether_ntoa() functions are not thread-safe.

       The ether_ntohost(), ether_hostton(),  ether_line(),  ether_ntoa_r()  and  ether_aton_r()  functions  are
       thread-safe.

CONFORMING TO

       4.3BSD, SunOS.

BUGS

       The glibc 2.2.5 implementation of ether_line() is broken.

SEE ALSO

       ethers(5)

COLOPHON

       This  page  is  part  of  release 3.54 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.