5a,5b program

5A SERVER

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<string.h>

#define SERV_TCP_PORT 1434

int main()

{

char p[15],q[25],s[15],r[15];

int sockfd,newsockfd,clilen,i=1,j,k,n;

struct sockaddr_in caddr,saddr;

char c;

if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)

  perror("server:socket error");

bzero((char*)&saddr,sizeof(saddr));

saddr.sin_family=AF_INET;

saddr.sin_addr.s_addr=htonl(INADDR_ANY);

saddr.sin_port=htons(SERV_TCP_PORT);

if((bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr)))<0)

  perror("Bind error");

listen(sockfd,5);

clilen=sizeof(caddr);

if((newsockfd=accept(sockfd,(struct sockaddr*)&caddr,&clilen))<0)

  perror("srever:Accept error");

printf("Enter the String:");

scanf("%s",q);

for(i=0;i<strlen(q);i+=4)

{

 strcpy(p,"");

 for(j=0;j<4;j++)

 {

   if((i+j)==strlen(q))

   {

     for(k=0;k<3;k++)

     if((j+k)%4)

        p[j+k]=' ';

     else

     {

       j=j+k+1;

       break;

     }

   }

   p[j]=q[i+j];

 }

 p[j]='\0';

 p[strlen(p)]='\0';

 printf("\n The frame is transmitted is %s\n",p);

 write(newsockfd,p,strlen(p)+1);

 read(newsockfd,s,5);

 sscanf(s,"%d",&n);

 if(n==-1)

  puts("\nNo error");

 else

 {

   printf("An error has occured in position %d\n",n);

   for(j=n;j<4;j++)

     r[j-n]=p[j];

   r[j-n]='\0';

   strcat(r,"");

   n=strlen(r);

   for(j=0;j<n;j++)

     r[n+j]=s[n+j-1+i];

   r[n+j]='\0';

   puts("\nRetransmiting");

   write(newsockfd,r,strlen(r)+1);

 }

}

5A CLIENT:

#include<stdio.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<stdlib.h>

#include<string.h>

#define SERV_TCP_PORT 8999

int main(){

char p[25],q[25];

int sockfd,flag=1,n,c,i;

struct sockaddr_in saddr;

FILE *fp;

bzero((char*)&saddr,sizeof(saddr));

saddr.sin_family= AF_INET;

saddr.sin_addr.s_addr=inet_addr("127.0.0.1");

saddr.sin_port=htons( SERV_TCP_PORT);

if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)

perror("Client::Socket Error");

if((connect(sockfd,(struct sockaddr*)&saddr,sizeof(saddr)))<0)

perror("Client::Connect Error");

while(1){

read(sockfd,q,25);

printf("the received Frame is %s\n ",q );

puts("Do u want to insert an error or not ( 1 - yes/0 - no)?");

scanf("%d",&c);

if(c){

puts("Enter the bit position you want to enter the error");

scanf("%d",&n);

sprintf(p,"%d",n);

write(sockfd,p,strlen(p)+1);

read(sockfd,q,25);

printf("The Retransmitted frame is %s \n ",q);}

else{

puts("No error");

n=-1;

sprintf(p,"%d",n);

write(sockfd,p,strlen(p)+1);

}}

puts("Connection terminated");

close(sockfd);

return 0;}

5B SERVER

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<string.h>

#define SERV_TCP_PORT 5308

int main()

{

char p[15],q[25],s[15],m[0];

int sockfd,newsockfd,clilen,i,j,k,n;

struct sockaddr_in caddr,saddr;

char c;

if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)

perror("server:socket error");

bzero((char*)&saddr,sizeof(saddr));

saddr.sin_family=AF_INET;

saddr.sin_addr.s_addr=htonl(INADDR_ANY);

saddr.sin_port=htons(SERV_TCP_PORT);

if((bind(sockfd,(struct sockaddr*)&saddr,sizeof(saddr)))<0)

perror("Bind error");

listen(sockfd,5);

clilen=sizeof(caddr);

if((newsockfd=accept(sockfd,(struct sockaddr*)&caddr,&clilen))<0)

perror("srever:Accept error");

printf("Enter the String:");

scanf("%s",q);

int len=strlen(q);

q[len]='\0';

for(i=0;i<len+1;i++)

{

do

{

m[0]=q[i];

if(m[0]!='\0')

printf("\n The frame is transmitted is %c\n",m[0]);

write(newsockfd,m,1);

read(newsockfd,s,25);

sscanf(s,"%d",&n);

if(n==1)

printf("RETRANSMITING");

}while(n==1);

}

puts("\n Terminated!!!");

close(newsockfd);

close(sockfd);

}

5B CLIENT:

#include<stdio.h>

#include<sys/types.h>

#include<sys/socket.h>

#include<netinet/in.h>

#include<arpa/inet.h>

#include<stdlib.h>

#include<string.h>

#define SERV_TCP_PORT 5308

int main()

{

char p[25],q[25],m;

int sockfd,flag=1,n,c,i;

struct sockaddr_in saddr;

FILE *fp;

bzero((char*)&saddr,sizeof(saddr));

saddr.sin_family=AF_INET;

saddr.sin_addr.s_addr=inet_addr("127.0.0.1");

saddr.sin_port=htons(SERV_TCP_PORT);

if((sockfd=socket(AF_INET,SOCK_STREAM,0))<0)

perror("Cli: con ERROR");

if((connect(sockfd,(struct sockaddr*)&saddr,sizeof(saddr)))<0)

perror("error");

while(1)

{

printf("reading:");

read(sockfd,q,1);

m=q[0];

if(m=='\0')

break;

printf("THE received Frame is %c \n ",m);

puts("1 for error 0 for done");

scanf("%d",&n);

sprintf(p,"%d",n);

write(sockfd,p,strlen(p)+1);

}

puts("DONE");

close(sockfd);

return 0;

}