windows network programming

IT COOKBOOKIT COOKBOOK

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Windows Network Programming

Chapter 01.

Intro. to Network and

Socket Programming


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Goal

• TCP/IP Protocol• Basic concept of socket• Windows socket overview• Writing and executing of Windows

socket application


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Internet Configuration

End System(PC, PDA, ...)

Router

End System(PC, PDA, ...)

Router

①

②

③

④


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TCP/IP Protocol

TCP/IP Protocol(OS)

Application

Router Router

TCP/IP Protocol(OS)

Application

End System End System


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TCP/IP Protocol Structure (1/6)

Network Access Layer

Internet Layer

Transport Layer

Application Layer

Device DriverNetwork Hardware

IP

TCP, UDP

TELNET, FTP, HTTP,SMTP, MIME, SNMP, ...

• TCP/IP Protocol Structure– Layering Structure


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TCP/IP Protocol Structure (2/6)

• Network access layer– Role

• Data transmission through physical network

– Components• Network hardware + device driver

– Addressing• physical address(MAC address)• Command: ‘ipconfig /all’

– Example• Ethernet


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TCP/IP Protocol Structure(3/6)

• Internet layer– Role

• Packet routing

– Addressing• IP address

• Transport layer– Role

• Data transfer to end system

– Addressing• port number

– Examples• TCP(Transmission Control Protocol), UDP(User

Datagram Protocol)


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• TCP and UDP

TCP UDP

Connection-oriented Protocol- Data transfer after connection setup

Connectionless Protocol- Data transfer winthout connection

Byte-stream service Datagram service

Reliable data transfer- Retransmission mechanism

Unreliable data transfer- No retransmission mechanism

1 to 1 communication(unicast)

1 to 1 communication(unicast)1 to N communication (broadcast),N to N Communication (multicast)


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• Application layer– Role

• Including some application protocol and services• Providing various application service

– Examples• Telnet, FTP, HTTP, SMTP etc.


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Packet transfer Principle (1/5)

• Packet– Control information defined by each protocol

(IP address, port number, error check code etc.) + data

– Depending on the location, header and trailer


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Packet transfer Principle(2/5)

• Packet transfer at sender side

Ethernet

IP

TCP

Application data

dataTCP Header

dataTCP HeaderIP Header

TCP Header

IP Header

Ethernet Header data Ethernet trailer


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• Packet transfer at receiver side

Ethernet

IP

TCP

Application data

dataTCP Header

dataTCP HeaderIP Header

TCP Header

IP Header

Ethernet Header

data Ethernet trailer


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• Packet transfer using Internet protocol


Internet Layer

Transport Layer

Application Layer


Internet Layer

Transport Layer

Application Layer


Internet Layer


Internet Layer

End system Router Router End system


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IP address and port number (1/3)

• IP 주소– Unique identifier of a internet host– IPv4: 32bit, IPv6: 128bit

• example) 147.46.114.70• example) loopback address: 127.0.0.1

• Port number– Unique process identifier


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IP address and port number (2/3)

• IP address and port number

TCP

IP

process process

process

UDP

Port number(0~65535)

IP address


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Client/server model

• Client/server Model• Server first executed• When client send the request, server processes

the request• Example: web client/server

Server Client

waiting

connecting


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socket concept (1/5)

• Three points of view① Data type② communication end-point③ Network programming interface


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socket concept(2/5)

• Data type– Each of client and server is identified by a

separate socket address– Example of socket address data type

• Struct sockaddr_in, in_addr

// file creation

int fd = open("myfile", ...);

...

read(fd, ...) // Reading

write(fd, ...) // Writing

// socket creation

SOCKET sock = socket(...);

...

recv(sock, ...) // Receive

send(sock, ...) // Send


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socket concept(3/5)

• Communication end-point– Socket requires three components

• protocol(TCP/IP, UDP/IP)• sender IP address, sender port number• receiver IP address, receiver port number


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socket concept(4/5)

• Communication end-point(cont’d)

client

send (sock, ...)

server

recv (sock, ...)

data

<client socket>• protocol: TCP/IP• IP address: 147.46.114.70• port number: 12023

<server socket>

• protocol : TCP/IP• IP address: 61.72.244.22• port number: 9001


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socket concept(5/5)

• Network programming interface– Socket is the interface between application

layer and transport layer in TCP/IP protocol stack

application

TCP

IP

UDP

application application

Socket interface

ICMP, IGMP


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Windows sockets (1/3)

• Windows Sockets, Winsock- Originated by Berkeley Software

Distribution UNIX- Included as API(Application Programming

Interface) since Windows 95 version


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Windows sockets(2/3)

• Winsock supported by windows version

• Supported protocols– TCP/IP, IPv6(windows XP or above),

IrDA(windows 98 or above), Bluetooth(windows XP SP2 or above), IPX/SPX, ATM, DECNet, TP4(Not supported since windows 2000), DLC(TP4(Not supported since windows XP), NetBEUI(Not supported since windows XP)

OSWinsock ver.

Windows 95 1.1 (2.2)

Windows 98/Me, Windows NT/2000/XP/2003 Server, Windows Vista/2008 Server/7

2.2

Windows CE 1.1 (2.2)


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Windows sockets(3/3)

• Structure

Winsock 2.xApplication

Winsock 1.xApplication

WINSOCK.DLL (16 bit)WSOCK32.DLL (32 bit)

WS2_32.DLL (32 bit)

Winsock 1.x API

Winsock 2.x API

TCP/IP IrDA IPX/SPX

MSWSOCK.DLL

...Bluetooth

Winsock 1.x Extended API


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Winsock application practice

• Source code: – Class webpage

• Sample Winsock application(server.cpp)

windows network programming

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