Compiled by: Jayakumar BalasubramanianWeb: http://www.jwritings.com

Email: b.jayakumar@gmail.com

Introduction Introduction to sockets The “Endian” concept Trivial functions Socket APIs Client server programming using sockets

Introduction

The “Endian” concept

Big-Endian

Little-Endian

Bit order transformation

Trivial functions

How does one talk to TCP/IP ?

Addressing in IP and TCP

Socket address

Socket APIs

API : Socket ()Use to create a socket.

fd = socket (family, type, protocol)

Family : AF_INET, AF_UNIX, AF_NS Type : SOCK_STREAM, SOCK_DGRAMProtocol : Protocol for a given socket

API: bind() [The anchor]

API: bind() Attach a transport address to a socket. status = bind (fd, addressp, addrlen); fd : Socket descriptor addressp : Pointer to address structure addrlen : Size of address structure

API: connect()

API : connect()The connect function is used by a TCP client to establish a connection with a TCP server

int fd, status, addrlen; struct sockaddr *addressp; status = connect (fd, addresssp, addrlen);

API: listen()

API: listen()listen() Prepares a socket to accept connections Must be used only on the server side of the

application before any connection request is accepted.

int fd, qlen, status; status = listen (fd, qlen);

fd : Socket descriptor qlen : Length of the queue

API : accept()

API : accept() Used in the server side of the connection to

accept incoming new connections When requests arrives it creates new socket,

accepts the connection on the new socket

int newfd, addrlen; struct sockaddr * addressp; newfd = accept (fd, addressp, & addrlen);

Connection establishment

API : send() Sends data over a communication channel Can be used in server and client side

int fd, len, flags; char *buff; sent = send (fd, buff, len, flags);

sent can be <= len

API : recv()Receives data over a communication channelCan be used in server and client side

int fd, len, flags, received; char *buff; received = recv (fd, buff, len, flags);

API: close() Close terminates both directions of data

transfer, reading and writing.

close( sockfd)

Web : http://www.jwritings.comEmail: b.jayakumar@gmail.com