SIMULATION OF SLIDING WINDOW PROTOCOLS USING C

SENDER

#include<sys/socket.h>

#include<sys/types.h>

#include<netinet/in.h>

#include<netdb.h>

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#include<unistd.h>

#include<errno.h>

int main()

{

int sock,bytes_received,connected,true=1,i=1,s,f=0,sin_size;

char send_data[1024],data[1024],c,fr[30]=" ";

struct sockaddr_in server_addr,client_addr;

if((sock=socket(AF_INET,SOCK_STREAM,0))==-1)

{

perror("Socket not created");

exit(1);

}

if(setsockopt(sock,SOL_SOCKET,SO_REUSEADDR,&true,sizeof(int))==-1)

{

perror("Setsockopt");

exit(1);

}

server_addr.sin_family=AF_INET;

server_addr.sin_port=htons(17000);

server_addr.sin_addr.s_addr=INADDR_ANY;

if(bind(sock,(struct sockaddr *)&server_addr,sizeof(struct sockaddr))==-1)

{

perror("Unable to bind");

exit(1);

}

if(listen(sock,5)==-1)

{

perror("Listen");

exit(1);

}

fflush(stdout);

sin_size=sizeof(struct sockaddr_in);

connected=accept(sock,(struct sockaddr *)&client_addr,&sin_size);

while(strcmp(fr,"exit")!=0)

{

printf("Enter Data Frame %d:(Enter exit for End): ",i);

scanf("%s",fr);

send(connected,fr,strlen(fr),0);

recv(sock,data,1024,0);

if(strlen(data)!=0)

printf("I got an acknowledgement : %s\n",data);

fflush(stdout);

i++;

}

close(sock);

return (0);

}

RECEIVER

#include<sys/socket.h>

#include<sys/types.h>

#include<netinet/in.h>

#include<netdb.h>

#include<stdio.h>

#include<string.h>

#include<stdlib.h>

#include<unistd.h>

#include<errno.h>

int main()

{

int sock,bytes_received,i=1;

char receive[30];

struct hostent *host;

struct sockaddr_in server_addr;

host=gethostbyname("127.0.0.1");

if((sock=socket(AF_INET,SOCK_STREAM,0))==-1)

{

perror("Socket not created");

exit(1);

}

printf("Socket created");

server_addr.sin_family=AF_INET;

server_addr.sin_port=htons(17000);

server_addr.sin_addr=*((struct in_addr *)host->h_addr);

bzero(&(server_addr.sin_zero),8);

if(connect(sock,(struct sockaddr *)&server_addr,sizeof(struct sockaddr))==-1)

{

perror("Connect");

exit(1);

}

while(1)

{

bytes_received=recv(sock,receive,20,0);

receive[bytes_received]='\0';

if(strcmp(receive,"exit")==0||strcmp(receive,"exit")==0)

{

close(sock);

break;

}

else

{

if(strlen(receive)<10)

{

printf("\n Frame %d data %s received\n",i,receive);

send(0,receive,strlen(receive),0);

}

else

{

send(0,"negative",10,0);

}

i++;

}

}

close(sock);

return(0);

}

OUTPUT

SENDER

$ cc sender.c

$ ./a.out

Enter Data Frame 1:(Enter exit for End): saveetha

Enter Data Frame 2:(Enter exit for End): mca

Enter Data Frame 3:(Enter exit for End): exit

$

RECEIVER

$ cc receiver.c

$ ./a.out

Socket created

Frame 1 data saveetha received

Frame 2 data mca received

$