ether_aton(3) — Linux manual page

ether_aton(3)           Library Functions Manual           ether_aton(3)

NAME         top

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

LIBRARY         top

       Standard C library (libc, -lc)

SYNOPSIS         top

       #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         top

       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         top

       For an explanation of the terms used in this section, see
       attributes(7).
       ┌───────────────────────────────────┬───────────────┬───────────┐
       │ Interface                         │ Attribute     │ Value     │
       ├───────────────────────────────────┼───────────────┼───────────┤
       │ ether_aton(), ether_ntoa()        │ Thread safety │ MT-Unsafe │
       ├───────────────────────────────────┼───────────────┼───────────┤
       │ ether_ntohost(), ether_hostton(), │ Thread safety │ MT-Safe   │
       │ ether_line(), ether_ntoa_r(),     │               │           │
       │ ether_aton_r()                    │               │           │
       └───────────────────────────────────┴───────────────┴───────────┘

STANDARDS         top

       None.

HISTORY         top

       4.3BSD, SunOS.

BUGS         top

       In glibc 2.2.5 and earlier, the implementation of ether_line() is
       broken.

SEE ALSO         top

       ethers(5)

COLOPHON         top

       This page is part of the man-pages (Linux kernel and C library
       user-space interface documentation) project.  Information about
       the project can be found at 
       ⟨https://www.kernel.org/doc/man-pages/⟩.  If you have a bug report
       for this manual page, see
       ⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
       This page was obtained from the tarball man-pages-6.9.1.tar.gz
       fetched from
       ⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
       2024-06-26.  If you discover any rendering problems in this HTML
       version of the page, or you believe there is a better or more up-
       to-date source for the page, or you have corrections or
       improvements to the information in this COLOPHON (which is not
       part of the original manual page), send a mail to
       man-pages@man7.org

Linux man-pages 6.9.1          2024-05-02                  ether_aton(3)

Pages that refer to this page: getent(1)

HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH.