EX4:Write a program to implement sliding window protocol using TCP socket

EX4:Write a program to Chat from server to client using TCP socket

Algorithm:

Server:

1.      Create a socket with the socket() system call.

2.     Bind the socket to an address using the bind() system call. For a server socket on the Internet, an address consists of a port number on the host machine.

3.     Listen for connections with the listen() system call.

4.   Accept a connection with the accept() system call. This call typically blocks until a client connects with the server.

5.      Get the date & time using ctime() system call.

6.      Send and receive data using the read() and write() system calls.

7.      Terminate the connections using close() system call.

Client:

1.      Create a socket with the socket() system call.

2.   Connect the socket to the address of the server using the connect() system call.

3.      Send and receive data using the read() and write() system calls.

4.      Terminate the connections using close() system call.

Server Program:

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define MAX 20
#define N 4
int main( int argc, char *argv[] ) {
    int socfd, clifd, addrlen;
    char buf[ MAX ];
    struct sockaddr_in myaddr;
    int sp, cp, ep;
    int inputBuf[ MAX ], ACK = -1;
    sp = 0;
    cp = sp;
    ep = sp + N;
if ( (socfd = socket( PF_INET, SOCK_STREAM, 0 )) < 0 )
        fprintf( stderr, "socket error\n" );
memset( &myaddr, 0, sizeof( &myaddr ) );   
    myaddr.sin_family = AF_INET;
    myaddr.sin_addr.s_addr = htonl( INADDR_ANY );
    myaddr.sin_port = htons( atoi( argv[1] ) );
    addrlen = sizeof( myaddr );
    if ( bind( socfd, (struct sockaddr *)&myaddr, addrlen ) < 0 )
        fprintf( stderr, "bind error\n" );
if ( listen( socfd, 1 ) < 0 )
        fprintf( stderr, "listen error\n" );
if ( (clifd = accept( socfd, (struct sockaddr *)&myaddr, &addrlen )) < 0 )
        fprintf( stderr, "accept error\n" );
while( cp < MAX ) {
        while( cp >= sp && cp <= ep ) {
            if( read( clifd, buf, sizeof(buf) ) > 0 ) {
                inputBuf[ cp++ ] = atoi( buf );
                printf( "%s received\n", buf );
            }}if( cp > 0 ) {
            sprintf( buf, "%d", cp-1 );
            if ( write( clifd, buf, sizeof(buf) ) != sizeof(buf) )
                fprintf( stderr, "write error\n" );
            else
                printf( "sending ACK %s\n", buf );
            sp = cp;
            ep = sp + N;   
        }}
    return 0;}
Client Program:

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <sys/select.h>
#include <arpa/inet.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define MAX 20
#define N 4
int main( int argc, char *argv[] ) {
    int socfd, clifd, addrlen;
    char buf[ MAX ];
    struct sockaddr_in  myaddr;
    int i, sp, cp, ep, inputBuf[ MAX ], ACK = -1;
    sp = 0;
    cp = sp;
    ep = sp + N;
for( i=0; i<MAX; i++ )
        inputBuf[i] = i;
if ( (socfd = socket( PF_INET, SOCK_STREAM, 0 )) < 0 )
        fprintf( stderr, "socket error" );
    myaddr.sin_family = AF_INET;
    myaddr.sin_addr.s_addr = htonl( INADDR_ANY );
    myaddr.sin_port = htons( atoi( argv[1] ) );
    addrlen = sizeof( struct sockaddr );
    if ( connect( socfd, (struct sockaddr *)&myaddr, addrlen ) < 0 )
        fprintf( stderr, "connect error" );
while( cp < MAX ) {
        while( cp >= sp && cp <= ep ) {
            sprintf( buf, "%d", inputBuf[ cp++ ] );
            if ( write( socfd, buf, sizeof(buf) ) != sizeof(buf) )
                fprintf( stderr, "write error" );
            else
                printf( "sending %s\n", buf );
        }
        if( read( socfd, buf, sizeof(buf) ) > 0 ) {
            ACK = atoi( buf );
            printf( "ACK %d received\n", ACK );
            sp = ACK+1;
            ep = sp + N;
}    }return 0;
}


OUTPUT:

server side:
[anandh@tecnetserver slide]$ cc slides.c -o server
[anandh@tecnetserver slide]$ ./server 5000
0 received
1 received
2 received
3 received
4 received
sending ACK 4
5 received
6 received
7 received
8 received
9 received
sending ACK 9
clientside:
[anandh@tecnetserver slide]$ cc slidec.c -o client
[anandh@tecnetserver slide]$ ./client 5000
sending 0
sending 1
sending 2
sending 3
sending 4
ACK 4 received
sending 5
sending 6
sending 7
sending 8
sending 9
ACK 9 received