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-
- INET(4) UNIX Programmer's Manual INET(4)
-
- NNAAMMEE
- iinneett - Internet protocol family
-
- SSYYNNOOPPSSIISS
- ##iinncclluuddee <<ssyyss//ttyyppeess..hh>>
- ##iinncclluuddee <<nneettiinneett//iinn..hh>>
-
- DDEESSCCRRIIPPTTIIOONN
- The Internet protocol family is a collection of protocols layered atop
- the _I_n_t_e_r_n_e_t _P_r_o_t_o_c_o_l (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 inter-
- face provides access to the IP protocol.
-
- AADDDDRREESSSSIINNGG
- Internet addresses are four byte quantities, stored in network standard
- format (on the VAX these are word and byte reversed). The include file
- <_n_e_t_i_n_e_t_/_i_n_._h> defines this address as a discriminated union.
-
- Sockets bound to the Internet protocol family utilize the following ad-
- dressing 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.
-
- PPRROOTTOOCCOOLLSS
- The Internet protocol family is comprised of the IP transport protocol,
- Internet Control Message Protocol (ICMP), 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 ab-
- straction. 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 address-
- es, in which the high-order 8 bits are the network number. Class B ad-
- dresses use the high-order 16 bits as the network field, and Class C ad-
- dresses have a 24-bit network part. Sites with a cluster of local net-
- works 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 lo-
- cal (host) portion of the address is further subdivided 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 en-
- abled and examined by the following ioctl(2) commands on a datagram sock-
- et in the Internet domain; they have the same form as the SIOCIFADDR com-
- mand (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 sub-
- nets are in use.
-
- SIOCGIFNETMASK Get interface network mask.
-
- SSEEEE AALLSSOO
- ioctl(2), socket(2), intro(4), tcp(4), udp(4), ip(4), icmp(4)
-
- "An Introductory 4.3 BSD Interprocess Communication Tutorial", _P_S_1, 7.
-
- "An Advanced 4.3 BSD Interprocess Communication Tutorial", _P_S_1, 8.
-
- CCAAVVEEAATT
- 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.
-
- HHIISSTTOORRYY
- The iinneett protocol interface appeared in 4.2BSD.
-
- 4.2 Berkeley Distribution June 5, 1993 2
-