184 lines
5.5 KiB
Groff
184 lines
5.5 KiB
Groff
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.\" Copyright (c) 1983, 1991 The Regents of the University of California.
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.\" All rights reserved.
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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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)inet.4 6.6 (Berkeley) 3/28/91
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.\"
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.Dd March 28, 1991
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.Dt INET 4
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.Os BSD 4.2
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.Sh NAME
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.Nm inet
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.Nd Internet protocol family
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.Sh SYNOPSIS
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.Fd #include <sys/types.h>
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.Fd #include <netinet/in.h>
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.Sh DESCRIPTION
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The Internet protocol family is a collection of protocols
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layered atop the
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.Em Internet Protocol
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.Pq Tn IP
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transport layer, and utilizing the Internet address format.
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The Internet family provides protocol support for the
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.Dv SOCK_STREAM , SOCK_DGRAM ,
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and
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.Dv SOCK_RAW
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socket types; the
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.Dv SOCK_RAW
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interface provides access to the
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.Tn IP
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protocol.
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.Sh ADDRESSING
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Internet addresses are four byte quantities, stored in
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network standard format (on the
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.Tn VAX
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these are word and byte
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reversed). The include file
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.Aq Pa netinet/in.h
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defines this address
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as a discriminated union.
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.Pp
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Sockets bound to the Internet protocol family utilize
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the following addressing structure,
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.Bd -literal -offset indent
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struct sockaddr_in {
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short sin_family;
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u_short sin_port;
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struct in_addr sin_addr;
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char sin_zero[8];
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};
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.Ed
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.Pp
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Sockets may be created with the local address
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.Dv INADDR_ANY
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to effect
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.Dq wildcard
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matching on incoming messages.
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The address in a
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.Xr connect 2
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or
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.Xr sendto 2
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call may be given as
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.Dv INADDR_ANY
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to mean
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.Dq this host .
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The distinguished address
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.Dv INADDR_BROADCAST
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is allowed as a shorthand for the broadcast address on the primary
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network if the first network configured supports broadcast.
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.Sh PROTOCOLS
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The Internet protocol family is comprised of
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the
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.Tn IP
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transport protocol, Internet Control
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Message Protocol
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.Pq Tn ICMP ,
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Transmission Control
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Protocol
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.Pq Tn TCP ,
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and User Datagram Protocol
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.Pq Tn UDP .
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.Tn TCP
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is used to support the
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.Dv SOCK_STREAM
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abstraction while
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.Tn UDP
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is used to support the
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.Dv SOCK_DGRAM
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abstraction. A raw interface to
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.Tn IP
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is available
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by creating an Internet socket of type
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.Dv SOCK_RAW .
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The
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.Tn ICMP
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message protocol is accessible from a raw socket.
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.Pp
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The 32-bit Internet address contains both network and host parts.
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It is frequency-encoded; the most-significant bit is clear
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in Class A addresses, in which the high-order 8 bits are the network
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number.
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Class B addresses use the high-order 16 bits as the network field,
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and Class C addresses have a 24-bit network part.
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Sites with a cluster of local networks and a connection to the
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.Tn DARPA
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Internet may chose to use a single network number for the cluster;
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this is done by using subnet addressing.
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The local (host) portion of the address is further subdivided
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into subnet and host parts.
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Within a subnet, each subnet appears to be an individual network;
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externally, the entire cluster appears to be a single, uniform
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network requiring only a single routing entry.
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Subnet addressing is enabled and examined by the following
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.Xr ioctl 2
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commands on a datagram socket in the Internet domain;
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they have the same form as the
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.Dv SIOCIFADDR
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command (see
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.Xr intro 4 ) .
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.Pp
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.Bl -tag -width SIOCSIFNETMASK
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.It Dv SIOCSIFNETMASK
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Set interface network mask.
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The network mask defines the network part of the address;
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if it contains more of the address than the address type would indicate,
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then subnets are in use.
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.It Dv SIOCGIFNETMASK
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Get interface network mask.
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.El
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.Sh SEE ALSO
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.Xr ioctl 2 ,
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.Xr socket 2 ,
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.Xr intro 4 ,
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.Xr tcp 4 ,
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.Xr udp 4 ,
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.Xr ip 4 ,
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.Xr icmp 4
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.Rs
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.%T "An Introductory 4.3 BSD Interprocess Communication Tutorial"
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.%B PS1
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.%N 7
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.Re
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.Rs
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.%T "An Advanced 4.3 BSD Interprocess Communication Tutorial"
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.%B PS1
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.%N 8
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.Re
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.Sh CAVEAT
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The Internet protocol support is subject to change as
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the Internet protocols develop. Users should not depend
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on details of the current implementation, but rather
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the services exported.
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.Sh HISTORY
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The
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.Nm
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protocol interface appeared in
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.Bx 4.2 .
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