inet(7F)inet(7F)NAME
inet - Internet protocol family
SYNOPSIS DESCRIPTION
The internet protocol family is a collection of protocols layered on top of the (IP) network layer, which utilizes the internet address
format. The internet family supports the SOCK_STREAM and SOCK_DGRAM socket types.
Addressing
Internet addresses are four byte entities. The include file defines this address as the structure
Sockets bound to the internet protocol family utilize an addressing structure called Pointers to this structure can be used in system calls
wherever they ask for a pointer to a
There are three fields of interest within this structure. The first is which must be set to AF_INET. The next is which specifies the port
number to be used on the desired host. The third is which is of type and specifies the address of the desired host.
Protocols
The internet protocol family is comprised of the IP network protocol, Internet Control Message Protocol (ICMP), Transmission Control Proto-
col (TCP), and User Datagram Protocol (UDP). TCP is used to support the socket type while UDP is used to support the socket type. The
ICMP message protocol and IP network protocol are not directly accessible.
The local port address is selected from independent domains for TCP and UDP sockets. This means that creating a TCP socket and binding it
to local port number 10000, for example, does not interfere with creating a UDP socket and also binding it to local port number 10000 at
the same time.
Port numbers in the range 1-1023 inclusive are reserved for use by the super-user only. Attempts to bind to port numbers in this range by
non-super-users fail and result in an error returned.
AUTHOR
was developed by the University of California, Berkeley.
SEE ALSO tcp(7P), udp(7P).
inet(7F)
Check Out this Related Man Page
INET(4) BSD Kernel Interfaces Manual INET(4)NAME
inet -- Internet protocol family
SYNOPSIS
#include <sys/types.h>
#include <netinet/in.h>
DESCRIPTION
The Internet protocol family is a collection of protocols layered atop the Internet Protocol (IP) transport layer, and utilizing the Internet
address format. The Internet family provides protocol support for the SOCK_STREAM, SOCK_DGRAM, and SOCK_RAW socket types; the SOCK_RAW
interface provides access to the IP protocol.
ADDRESSING
Internet addresses are four byte quantities, stored in network standard format (on the VAX these are word and byte reversed). The include
file <netinet/in.h> defines this address as a discriminated union.
Sockets bound to the Internet protocol family utilize the following addressing structure,
struct sockaddr_in {
short sin_family;
u_short sin_port;
struct in_addr sin_addr;
char sin_zero[8];
};
Sockets may be created with the local address INADDR_ANY to effect ``wildcard'' matching on incoming messages. The address in a connect(2)
or sendto(2) call may be given as INADDR_ANY to mean ``this host''. The distinguished address INADDR_BROADCAST is allowed as a shorthand for
the broadcast address on the primary network if the first network configured supports broadcast.
PROTOCOLS
The Internet protocol family is comprised of the IP transport protocol, Internet Control Message Protocol (ICMP), Transmission Control Proto-
col (TCP), and User Datagram Protocol (UDP). TCP is used to support the SOCK_STREAM abstraction while UDP is used to support the SOCK_DGRAM
abstraction. A raw interface to IP is available by creating an Internet socket of type SOCK_RAW. The ICMP message protocol is accessible
from a raw socket.
The 32-bit Internet address contains both network and host parts. It is frequency-encoded; the most-significant bit is clear in Class A
addresses, in which the high-order 8 bits are the network number. Class B addresses use the high-order 16 bits as the network field, and
Class C addresses have a 24-bit network part. Sites with a cluster of local networks and a connection to the Internet may chose to use a
single network number for the cluster; this is done by using subnet addressing. The local (host) portion of the address is further subdi-
vided into subnet and host parts. Within a subnet, each subnet appears to be an individual network; externally, the entire cluster appears
to be a single, uniform network requiring only a single routing entry. Subnet addressing is enabled and examined by the following ioctl(2)
commands on a datagram socket in the Internet domain; they have the same form as the SIOCIFADDR command (see intro(4)).
SIOCSIFNETMASK Set interface network mask. The network mask defines the network part of the address; if it contains more of the address
than the address type would indicate, then subnets are in use.
SIOCGIFNETMASK Get interface network mask.
SEE ALSO ioctl(2), socket(2), intro(4), tcp(4), udp(4), ip(4), icmp(4)
"An Introductory 4.3 BSD Interprocess Communication Tutorial", PS1, 7.
"An Advanced 4.3 BSD Interprocess Communication Tutorial", PS1, 8.
CAVEAT
The Internet protocol support is subject to change as the Internet protocols develop. Users should not depend on details of the current
implementation, but rather the services exported.
HISTORY
The inet protocol interface appeared in 4.2BSD.
4.2 Berkeley Distribution June 5, 1993 4.2 Berkeley Distribution