INtime SDK Help


#include <sys/types.h>
#include <netinet/in.h>

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.


Internet addresses are four byte quantities, stored in network standard format (on little endian machines, such as the alpha, amd64, i386 and ia64 these are word and byte reversed). The include file defines this address as a discriminated union.

Sockets bound to the Internet protocol family utilize the following addressing structure,

struct sockaddr_in {
  uint8_t          sin_len;
  sa_family_t      sin_family;
  in_port_t        sin_port;
  struct in_addr  sin_addr;
  char     sin_zero[8];

Sockets may be created with the local address INADDR_ANY to affect wildcard' matching on incoming messages. The address in a connect or sendto 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.


The Internet protocol family is comprised of the IP network protocol, Internet Control Message Protocol (ICMP), Internet Group Management Protocol (IGMP), Transmission Control Protocol (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. However, direct examination of addresses is discouraged. For those programs which absolutely need to break addresses into their component parts, the following ioctl commands are provided for a datagram socket in the Internet domain; they have the same form as the SIOCIFADDR command.

MIB Variables

A number of variables are implemented in the net.inet branch of the sysctl MIB. In addition to the variables supported by the transport protocols (for which the respective manual pages may be consulted), the following general variables are defined:


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.


The inet protocol interface appeared in 4.2BSD. The 'protocol cloning' code appeared in FreeBSD 2.1.


Versions Link to
INtime 4.0 netlib.lib
See Also