306 lines
7.8 KiB
Groff
306 lines
7.8 KiB
Groff
.\" Copyright (c) 1983, 1990, 1991, 1993
|
|
.\" The Regents of the University of California. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\" 4. Neither the name of the University nor the names of its contributors
|
|
.\" may be used to endorse or promote products derived from this software
|
|
.\" without specific prior written permission.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
|
|
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
|
|
.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
|
|
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
|
|
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
|
|
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
|
|
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
|
|
.\" SUCH DAMAGE.
|
|
.\"
|
|
.\" From: @(#)inet.3 8.1 (Berkeley) 6/4/93
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.Dd June 14, 2007
|
|
.Dt INET 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm inet_aton ,
|
|
.Nm inet_addr ,
|
|
.Nm inet_network ,
|
|
.Nm inet_ntoa ,
|
|
.Nm inet_ntoa_r ,
|
|
.Nm inet_ntop ,
|
|
.Nm inet_pton ,
|
|
.Nm inet_makeaddr ,
|
|
.Nm inet_lnaof ,
|
|
.Nm inet_netof
|
|
.Nd Internet address manipulation routines
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.Sh SYNOPSIS
|
|
.In sys/types.h
|
|
.In sys/socket.h
|
|
.In netinet/in.h
|
|
.In arpa/inet.h
|
|
.Ft int
|
|
.Fn inet_aton "const char *cp" "struct in_addr *pin"
|
|
.Ft in_addr_t
|
|
.Fn inet_addr "const char *cp"
|
|
.Ft in_addr_t
|
|
.Fn inet_network "const char *cp"
|
|
.Ft char *
|
|
.Fn inet_ntoa "struct in_addr in"
|
|
.Ft char *
|
|
.Fo inet_ntoa_r
|
|
.Fa "struct in_addr in"
|
|
.Fa "char *buf"
|
|
.Fa "socklen_t size"
|
|
.Fc
|
|
.Ft const char *
|
|
.Fo inet_ntop
|
|
.Fa "int af"
|
|
.Fa "const void * restrict src"
|
|
.Fa "char * restrict dst"
|
|
.Fa "socklen_t size"
|
|
.Fc
|
|
.Ft int
|
|
.Fn inet_pton "int af" "const char * restrict src" "void * restrict dst"
|
|
.Ft struct in_addr
|
|
.Fn inet_makeaddr "in_addr_t net" "in_addr_t lna"
|
|
.Ft in_addr_t
|
|
.Fn inet_lnaof "struct in_addr in"
|
|
.Ft in_addr_t
|
|
.Fn inet_netof "struct in_addr in"
|
|
.Sh DESCRIPTION
|
|
The routines
|
|
.Fn inet_aton ,
|
|
.Fn inet_addr
|
|
and
|
|
.Fn inet_network
|
|
interpret character strings representing
|
|
numbers expressed in the Internet standard
|
|
.Ql .\&
|
|
notation.
|
|
.Pp
|
|
The
|
|
.Fn inet_pton
|
|
function converts a presentation format address (that is, printable form
|
|
as held in a character string) to network format (usually a
|
|
.Ft struct in_addr
|
|
or some other internal binary representation, in network byte order).
|
|
It returns 1 if the address was valid for the specified address family, or
|
|
0 if the address was not parseable in the specified address family, or -1
|
|
if some system error occurred (in which case
|
|
.Va errno
|
|
will have been set).
|
|
This function is presently valid for
|
|
.Dv AF_INET
|
|
and
|
|
.Dv AF_INET6 .
|
|
.Pp
|
|
The
|
|
.Fn inet_aton
|
|
routine interprets the specified character string as an Internet address,
|
|
placing the address into the structure provided.
|
|
It returns 1 if the string was successfully interpreted,
|
|
or 0 if the string is invalid.
|
|
The
|
|
.Fn inet_addr
|
|
and
|
|
.Fn inet_network
|
|
functions return numbers suitable for use
|
|
as Internet addresses and Internet network
|
|
numbers, respectively.
|
|
.Pp
|
|
The function
|
|
.Fn inet_ntop
|
|
converts an address
|
|
.Fa *src
|
|
from network format
|
|
(usually a
|
|
.Ft struct in_addr
|
|
or some other binary form, in network byte order) to presentation format
|
|
(suitable for external display purposes).
|
|
The
|
|
.Fa size
|
|
argument specifies the size, in bytes, of the buffer
|
|
.Fa *dst .
|
|
.Dv INET_ADDRSTRLEN
|
|
and
|
|
.Dv INET6_ADDRSTRLEN
|
|
define the maximum size required to convert an address of the respective
|
|
type.
|
|
It returns NULL if a system error occurs (in which case,
|
|
.Va errno
|
|
will have been set), or it returns a pointer to the destination string.
|
|
This function is presently valid for
|
|
.Dv AF_INET
|
|
and
|
|
.Dv AF_INET6 .
|
|
.Pp
|
|
The routine
|
|
.Fn inet_ntoa
|
|
takes an Internet address and returns an
|
|
.Tn ASCII
|
|
string representing the address in
|
|
.Ql .\&
|
|
notation.
|
|
The routine
|
|
.Fn inet_ntoa_r
|
|
is the reentrant version of
|
|
.Fn inet_ntoa .
|
|
The routine
|
|
.Fn inet_makeaddr
|
|
takes an Internet network number and a local
|
|
network address and constructs an Internet address
|
|
from it.
|
|
The routines
|
|
.Fn inet_netof
|
|
and
|
|
.Fn inet_lnaof
|
|
break apart Internet host addresses, returning
|
|
the network number and local network address part,
|
|
respectively.
|
|
.Pp
|
|
All Internet addresses are returned in network
|
|
order (bytes ordered from left to right).
|
|
All network numbers and local address parts are
|
|
returned as machine byte order integer values.
|
|
.Sh INTERNET ADDRESSES
|
|
Values specified using the
|
|
.Ql .\&
|
|
notation take one
|
|
of the following forms:
|
|
.Bd -literal -offset indent
|
|
a.b.c.d
|
|
a.b.c
|
|
a.b
|
|
a
|
|
.Ed
|
|
.Pp
|
|
When four parts are specified, each is interpreted
|
|
as a byte of data and assigned, from left to right,
|
|
to the four bytes of an Internet address.
|
|
Note
|
|
that when an Internet address is viewed as a 32-bit
|
|
integer quantity on the
|
|
.Tn VAX
|
|
the bytes referred to
|
|
above appear as
|
|
.Dq Li d.c.b.a .
|
|
That is,
|
|
.Tn VAX
|
|
bytes are
|
|
ordered from right to left.
|
|
.Pp
|
|
When a three part address is specified, the last
|
|
part is interpreted as a 16-bit quantity and placed
|
|
in the right-most two bytes of the network address.
|
|
This makes the three part address format convenient
|
|
for specifying Class B network addresses as
|
|
.Dq Li 128.net.host .
|
|
.Pp
|
|
When a two part address is supplied, the last part
|
|
is interpreted as a 24-bit quantity and placed in
|
|
the right most three bytes of the network address.
|
|
This makes the two part address format convenient
|
|
for specifying Class A network addresses as
|
|
.Dq Li net.host .
|
|
.Pp
|
|
When only one part is given, the value is stored
|
|
directly in the network address without any byte
|
|
rearrangement.
|
|
.Pp
|
|
All numbers supplied as
|
|
.Dq parts
|
|
in a
|
|
.Ql .\&
|
|
notation
|
|
may be decimal, octal, or hexadecimal, as specified
|
|
in the C language (i.e., a leading 0x or 0X implies
|
|
hexadecimal; otherwise, a leading 0 implies octal;
|
|
otherwise, the number is interpreted as decimal).
|
|
.Sh DIAGNOSTICS
|
|
The constant
|
|
.Dv INADDR_NONE
|
|
is returned by
|
|
.Fn inet_addr
|
|
and
|
|
.Fn inet_network
|
|
for malformed requests.
|
|
.Sh ERRORS
|
|
The
|
|
.Fn inet_ntop
|
|
call fails if:
|
|
.Bl -tag -width Er
|
|
.It Bq Er ENOSPC
|
|
.Fa size
|
|
was not large enough to store the presentation form of the address.
|
|
.It Bq Er EAFNOSUPPORT
|
|
.Fa *src
|
|
was not an
|
|
.Dv AF_INET
|
|
or
|
|
.Dv AF_INET6
|
|
family address.
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr byteorder 3 ,
|
|
.Xr getaddrinfo 3 ,
|
|
.Xr gethostbyname 3 ,
|
|
.Xr getnameinfo 3 ,
|
|
.Xr getnetent 3 ,
|
|
.Xr inet_net 3 ,
|
|
.Xr hosts 5 ,
|
|
.Xr networks 5
|
|
.Rs
|
|
.%R RFC
|
|
.%N 2373
|
|
.%D July 1998
|
|
.%T "IP Version 6 Addressing Architecture"
|
|
.Re
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn inet_ntop
|
|
and
|
|
.Fn inet_pton
|
|
functions conform to
|
|
.St -xns5.2 .
|
|
Note that
|
|
.Fn inet_pton
|
|
does not accept 1-, 2-, or 3-part dotted addresses; all four parts
|
|
must be specified and are interpreted only as decimal values.
|
|
This is a narrower input set than that accepted by
|
|
.Fn inet_aton .
|
|
.Sh HISTORY
|
|
These
|
|
functions appeared in
|
|
.Bx 4.2 .
|
|
.Sh BUGS
|
|
The value
|
|
.Dv INADDR_NONE
|
|
(0xffffffff) is a valid broadcast address, but
|
|
.Fn inet_addr
|
|
cannot return that value without indicating failure.
|
|
The newer
|
|
.Fn inet_aton
|
|
function does not share this problem.
|
|
The problem of host byte ordering versus network byte ordering is
|
|
confusing.
|
|
The string returned by
|
|
.Fn inet_ntoa
|
|
resides in a static memory area.
|
|
.Pp
|
|
The
|
|
.Fn inet_addr
|
|
function should return a
|
|
.Fa struct in_addr .
|