©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl1 1 Chapter 16 Socket Interface

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl2 2 CONTENTS SOME DEFINITIONS SOCKETS BYTE ORDERING ADDRESS TRANSFORMATION BYTE MANIPULATION FUNCTIONS INFORMATION ABOUT REMOTE HOST SOCKET SYSTEM CALLS CONNECTIONLESS ITERATIVE SERVER

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl3 3 CONTENTS (continued) UDP CLIENT-SERVER PROGRAMS CONNECTION-ORIENTED CONCURRENT SERVER TCP CLIENT-SERVER PROGRAMS

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl4 4 SOME DEFINITIONS 16.1

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl5 5 Figure 16-1 Data types

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl6 6 Figure 16-2 Internet address structure

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl7 7 SOCKETS 16.2

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl8 8 Figure 16-3 Socket address

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl9 9 Figure 16-4 Socket structure

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl10 10 Figure 16-5 Socket types

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl11 11 BYTE ORDERING 16.3

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl12 12 Figure 16-6 Big-endian byte order

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl13 13 Figure 16-7 Little-endian byte order

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl14 14 The byte order for the TCP/IP protocol suite is big endian.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl15 15 Figure 16-8 Byte-order transformation

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl16 16 Figure 16-9 Declarations for byte-order transformation

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl17 17 ADDRESS TRANSFORMATION 16.4

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl18 18 Figure Address transformation

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl19 19 Figure Declarations for address transformation functions

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl20 20 BYTE MANIPULATION FUNCTIONS 16.5

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl21 21 Figure Declarations for byte-manipulation functions

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl22 22 INFORMATION ABOUT REMOTE HOST 16.6

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl23 23 Figure Hostent structure

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl24 24 SOCKET SYSTEM CALLS 16.7

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl25 25 Figure Declaration for socket function Create a blank socket.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl26 26 Figure Declaration for bind function Server Application binds a socket to a given socket address.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl27 27 Figure Declaration for connect function Client Application actively opens a connection with a remote server socket

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl28 28 Figure Declaration for listen function Server Application is ready to receive connection requests

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl29 29 Figure 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.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl30 30 Figure Declaration for sendto function Application sends UDP data to a remote socket

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl31 31 Figure 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

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl32 32 Figure 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.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl33 33 Figure Declaration for write function Send a message to a specific Stream (i.e. TCP) socket. Assumes that the connection has already been opened.

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl34 34 Figure Declaration for close function Terminate the TCP connection

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl35 35 CONNECTIONLESS ITERATIVE SERVER 16.8

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl36 36 Socket interface for connectionless iterative server

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl37 37 UDP CLIENT-SERVER PROGRAMS 16.9

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl38 38 CONNECTION-ORIENTED CONCURRENT SERVER 16.10

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl39 39 Figure Socket interface for connection-oriented concurrent server

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl40 40 Figure (repeated), Part I

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl41 41 Figure (repeated), Part II

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl42 42 Figure 16-27, Part I Client and Server

©The McGraw-Hill Companies, Inc., 2000© Adapted for use at JMU by Mohamed Aboutabl, 2003Mohamed Aboutabl43 43 Figure 16-27, Part II