162 lines
5.0 KiB
Groff
162 lines
5.0 KiB
Groff
.\" $NetBSD: inet_net.3,v 1.4 1999/03/22 19:44:52 garbled Exp $
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.\"
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.\" Copyright (c) 1997 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Luke Mewburn.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 4. Neither the name of The NetBSD Foundation nor the names of its
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.\" contributors may be used to endorse or promote products derived
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.\" from this software without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd August 18, 2016
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.Dt INET_NET 3
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.Os
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.Sh NAME
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.Nm inet_net_ntop ,
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.Nm inet_net_pton
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.Nd Internet network number manipulation routines
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In sys/socket.h
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.In netinet/in.h
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.In arpa/inet.h
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.Ft char *
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.Fn inet_net_ntop "int af" "const void *src" "int bits" "char *dst" "size_t size"
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.Ft int
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.Fn inet_net_pton "int af" "const char *src" "void *dst" "size_t size"
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.Sh DESCRIPTION
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The
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.Fn inet_net_ntop
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function converts an Internet network number from network format (usually a
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.Vt "struct in_addr"
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or some other binary form, in network byte order) to CIDR presentation format
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(suitable for external display purposes).
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The
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.Fa bits
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argument
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is the number of bits in
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.Fa src
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that are the network number.
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It returns
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.Dv NULL
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if a system error occurs (in which case,
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.Va errno
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will have been set), or it returns a pointer to the destination string.
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.Pp
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The
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.Fn inet_net_pton
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function converts a presentation format Internet network number (that is,
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printable form as held in a character string) to network format (usually a
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.Vt "struct in_addr"
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or some other internal binary representation, in network byte order).
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It returns the number of bits (either computed based on the class, or
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specified with /CIDR), or \-1 if a failure occurred
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(in which case
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.Va errno
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will have been set.
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It will be set to
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.Er ENOENT
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if the Internet network number was not valid).
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.Pp
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The currently supported values for
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.Fa af
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are
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.Dv AF_INET
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and
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.Dv AF_INET6 .
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The
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.Fa size
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argument
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is the size of the result buffer
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.Fa dst .
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.Sh NETWORK NUMBERS (IP VERSION 4)
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Internet network numbers may be specified in one of the following forms:
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.Bd -literal -offset indent
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a.b.c.d/bits
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a.b.c.d
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a.b.c
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a.b
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a
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.Ed
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.Pp
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When four parts are specified, each is interpreted
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as a byte of data and assigned, from left to right,
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to the four bytes of an Internet network number.
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Note
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that when an Internet network number is viewed as a 32-bit
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integer quantity on a system that uses little-endian
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byte order (such as the
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.Tn Intel 386 , 486 ,
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and
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.Tn Pentium
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processors) the bytes referred to above appear as
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.Dq Li d.c.b.a .
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That is, little-endian bytes are ordered from right to left.
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.Pp
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When a three part number is specified, the last
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part is interpreted as a 16-bit quantity and placed
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in the rightmost two bytes of the Internet network number.
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This makes the three part number format convenient
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for specifying Class B network numbers as
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.Dq Li 128.net.host .
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.Pp
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When a two part number is supplied, the last part
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is interpreted as a 24-bit quantity and placed in
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the rightmost three bytes of the Internet network number.
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This makes the two part number format convenient
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for specifying Class A network numbers as
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.Dq Li net.host .
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.Pp
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When only one part is given, the value is stored
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directly in the Internet network number without any byte
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rearrangement.
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.Pp
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All numbers supplied as
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.Dq parts
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in a
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.Ql \&.
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notation
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may be decimal, octal, or hexadecimal, as specified
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in the C language (i.e., a leading 0x or 0X implies
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hexadecimal; otherwise, a leading 0 implies octal;
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otherwise, the number is interpreted as decimal).
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.\"
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.\" .Sh NETWORK NUMBERS (IP VERSION 6)
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.\" XXX - document this!
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.\"
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.Sh SEE ALSO
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.Xr byteorder 3 ,
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.Xr inet 3 ,
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.Xr networks 5
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.Sh HISTORY
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The
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.Fn inet_net_ntop
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and
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.Fn inet_net_pton
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functions appeared in BIND 4.9.4.
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