| .\" Copyright 2002 Ian Redfern (redferni@logica.com) |
| .\" |
| .\" %%%LICENSE_START(VERBATIM) |
| .\" Permission is granted to make and distribute verbatim copies of this |
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| .\" |
| .\" Permission is granted to copy and distribute modified versions of this |
| .\" manual under the conditions for verbatim copying, provided that the |
| .\" entire resulting derived work is distributed under the terms of a |
| .\" permission notice identical to this one. |
| .\" |
| .\" Since the Linux kernel and libraries are constantly changing, this |
| .\" manual page may be incorrect or out-of-date. The author(s) assume no |
| .\" responsibility for errors or omissions, or for damages resulting from |
| .\" the use of the information contained herein. The author(s) may not |
| .\" have taken the same level of care in the production of this manual, |
| .\" which is licensed free of charge, as they might when working |
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| .\" Formatted or processed versions of this manual, if unaccompanied by |
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| .\" %%%LICENSE_END |
| .\" |
| .\" References consulted: |
| .\" Linux libc source code |
| .\" FreeBSD 4.4 man pages |
| .\" |
| .\" Minor additions, aeb, 2013-06-21 |
| .\" |
| .TH ETHER_ATON 3 2021-03-22 "GNU" "Linux Programmer's Manual" |
| .SH NAME |
| ether_aton, ether_ntoa, ether_ntohost, ether_hostton, ether_line, |
| ether_ntoa_r, ether_aton_r \- Ethernet address manipulation routines |
| .SH SYNOPSIS |
| .nf |
| .B #include <netinet/ether.h> |
| .PP |
| .BI "char *ether_ntoa(const struct ether_addr *" addr ); |
| .BI "struct ether_addr *ether_aton(const char *" asc ); |
| .PP |
| .BI "int ether_ntohost(char *" hostname ", const struct ether_addr *" addr ); |
| .BI "int ether_hostton(const char *" hostname ", struct ether_addr *" addr ); |
| .PP |
| .BI "int ether_line(const char *" line ", struct ether_addr *" addr , |
| .BI " char *" hostname ); |
| .PP |
| /* GNU extensions */ |
| .BI "char *ether_ntoa_r(const struct ether_addr *" addr ", char *" buf ); |
| .PP |
| .BI "struct ether_addr *ether_aton_r(const char *" asc , |
| .BI " struct ether_addr *" addr ); |
| .fi |
| .SH DESCRIPTION |
| .BR ether_aton () |
| converts the 48-bit Ethernet host address |
| .I 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. |
| .BR ether_aton () |
| returns NULL if the address is invalid. |
| .PP |
| The |
| .BR ether_ntoa () |
| function converts the Ethernet host address |
| .I 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. |
| .PP |
| The |
| .BR ether_ntohost () |
| function maps an Ethernet address to the |
| corresponding hostname in |
| .I /etc/ethers |
| and returns nonzero if it cannot be found. |
| .PP |
| The |
| .BR ether_hostton () |
| function maps a hostname to the |
| corresponding Ethernet address in |
| .I /etc/ethers |
| and returns nonzero if it cannot be found. |
| .PP |
| The |
| .BR ether_line () |
| function parses a line in |
| .I /etc/ethers |
| format (ethernet address followed by whitespace followed by |
| hostname; \(aq#\(aq introduces a comment) and returns an address |
| and hostname pair, or nonzero if it cannot be parsed. |
| The buffer pointed to by |
| .I hostname |
| must be sufficiently long, for example, have the same length as |
| .IR line . |
| .PP |
| The functions |
| .BR ether_ntoa_r () |
| and |
| .BR ether_aton_r () |
| are reentrant |
| thread-safe versions of |
| .BR ether_ntoa () |
| and |
| .BR ether_aton () |
| respectively, and do not use static buffers. |
| .PP |
| The structure |
| .I ether_addr |
| is defined in |
| .I <net/ethernet.h> |
| as: |
| .PP |
| .in +4n |
| .EX |
| struct ether_addr { |
| uint8_t ether_addr_octet[6]; |
| } |
| .EE |
| .in |
| .SH ATTRIBUTES |
| For an explanation of the terms used in this section, see |
| .BR attributes (7). |
| .ad l |
| .nh |
| .TS |
| allbox; |
| lbx lb lb |
| l l l. |
| Interface Attribute Value |
| T{ |
| .BR ether_aton (), |
| .BR ether_ntoa () |
| T} Thread safety MT-Unsafe |
| T{ |
| .BR ether_ntohost (), |
| .BR ether_hostton (), |
| .BR ether_line (), |
| .BR ether_ntoa_r (), |
| .BR ether_aton_r () |
| T} Thread safety MT-Safe |
| .TE |
| .hy |
| .ad |
| .sp 1 |
| .SH CONFORMING TO |
| 4.3BSD, SunOS. |
| .SH BUGS |
| In glibc 2.2.5 and earlier, the implementation of |
| .BR ether_line () |
| .\" The fix was presumably commit c0a0f9a32c8baa6ab93d00eb42d92c02e9e146d7 |
| .\" which was in glibc 2.3 |
| is broken. |
| .SH SEE ALSO |
| .BR ethers (5) |