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Chapter 16

SocketInterface

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CONTENTSCONTENTS• SOME DEFINITIONS• SOCKETS• BYTE ORDERING• ADDRESS TRANSFORMATION• BYTE MANIPULATION FUNCTIONS• INFORMATION ABOUT REMOTE HOST• SOCKET SYSTEM CALLS• CONNECTIONLESS ITERATIVE SERVER

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CONTENTS (continued)CONTENTS (continued)• UDP CLIENT-SERVER PROGRAMS• CONNECTION-ORIENTED CONCURRENT SERVER• TCP CLIENT-SERVER PROGRAMS

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SOME DEFINITIONS

16.116.1

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Figure 16-1

Data types

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Figure 16-2

Internet address structure

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SOCKETS

16.216.2

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Figure 16-3

Socket address

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Figure 16-4

Socket structure

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Figure 16-5

Socket types

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BYTE ORDERING

16.316.3

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Figure 16-6

Big-endian byte order

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Figure 16-7

Little-endian byte order

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The byte order for the TCP/IPThe byte order for the TCP/IPprotocol suite is big endian.protocol suite is big endian.

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Figure 16-8

Byte-order transformation

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Figure 16-9

Declarations for byte-order transformation

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ADDRESSTRANSFORMATION

16.416.4

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Figure 16-10

Address transformation

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Figure 16-11

Declarations for address transformation

functions

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BYTEMANIPULATION

FUNCTIONS

16.516.5

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Figure 16-12

Declarations for byte-manipulation functions

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INFORMATIONABOUT REMOTE

HOST

16.616.6

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Figure 16-14

Hostent structure

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SOCKET SYSTEMCALLS

16.716.7

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Figure 16-15

Declaration for socket function

Create a blank socket.

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Figure 16-16

Declaration for bind function

Server Application binds a socket to a given socket address.

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Figure 16-17

Declaration for connect function

Client Application actively opens a connection with a remote server socket

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Figure 16-18

Declaration for listen function

Server Application is ready to receive connection requests

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Figure 16-19

Declaration for accept function

Server Application accepts the next connection request. A new “child” socket is created and initialized by the Operating System. Its socket descriptor is the “return value”

If no requests pending, sleep.

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Figure 16-20

Declaration for sendto function

Application sends UDP data to a remote socket

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Figure 16-21

Declaration for recvfrom function

Get the next message arriving at a socket, as well as the socket address of the sender.

Usually used by a UDP process

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Figure 16-22

Declaration for read function

Read the next message arriving at a specific Stream (i.e. TCP) socket.

Assumes that the connection has already been opened.

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Figure 16-23

Declaration for write function

Send a message to a specific Stream (i.e. TCP) socket. Assumes that the connection has already been opened.

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Figure 16-24

Declaration for close function

Terminate the TCP connection

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CONNECTIONLESSITERATIVE

SERVER

16.816.8

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Socket interfacefor connectionless

iterative server

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UDP CLIENT-SERVERPROGRAMS

16.916.9

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CONNECTION-ORIENTEDCONCURRENT SERVER

16.1016.10

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Figure 16-26

Socket interfacefor connection-oriented

concurrent server

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Figure 16-26 (repeated), Part I

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Figure 16-26 (repeated), Part II

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Figure 16-27, Part I

Clientand

Server

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Figure 16-27, Part II