ether_aton(3) — Linux manual page

ether_aton(3)           Library Functions Manual           ether_aton(3)

NAME

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

LIBRARY

       Standard C library (libc, -lc)

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

       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

       None.

HISTORY

       4.3BSD, SunOS.

BUGS

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

SEE ALSO

       ethers(5)

COLOPHON

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

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