Question

Develop a client /server talk application in C or C++. You should run your server program first, and then open another window if you use loopback to connect the local host again, or you may go to another machine to run the client program that will connect to the server program. In this case you must find the server’s IP address first, and then connect to it.

If you use loopback, your procedure may look like:

➢ Server

Server is ready to talk… …

Open another window, and then run the client program

*You should use netstat | head command line to check if the server is in listening state.

➢ Client 127.0.0.1

*You should use netstat | head command line to check if the server and client processes are in the established state.

If you use two machines to run your programs, your procedure may look like:

➢ Server

Server is ready to talk… …

Open another window, and then run the client program

*You should use netstat | head command to check if the server is in listen state

➢ Client server_IP_ address

*You should use netstat | head command to check if the server and client processes are in the established state.

After establishing connection, the server and client programs will be ready to talk. You should start talking from the client program, and then the server responds to it. The conversation will continue to talk to each other until the client quitsby hitting Ctrl+D .

Client​​​​server

Hello​​​​à​Hello

How are you?​​ß​How are you?

I am fine.​​à​​I am fine.

Let us begin to work​ß​Let us begin to work

…​…

Hit Ctrl + D to terminate the conversation.

You might use the echo server and client application as an example to develop your talk program.

Requirements:

1. Write a readme file to explain how to run your program (5%);

2. Draw a data flow diagram to show your program design (10%);

3. Write a makefile that compiles your server and client programs (5%);

4. Comment your code properly (10%), and

Answer 1

1. ----------- README -----------------------

first execute server

./server

then in another window execute client by giving server_ip_address as a command line argument

./client 127.0.0.1

2.

3.

--------------------------- Makefile ----------------------------------

for server:

compile:
   gcc server.c -o server

for client:

compile:
   gcc client.c -o client

4.

server code:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAX 1024

int main(int argc, char *argv[])
{
   struct sockaddr_in server, client;
   int sock, new;
   int sockaddr_len = sizeof(struct sockaddr_in);
   int data;
   char buffer[MAX];
  
    //creating socket and checking whether socket was created or not
   if((sock = socket(AF_INET, SOCK_STREAM, 0)) == -1)
   {
       perror("socket");
       exit(-1);
   }
  
    //server details
   server.sin_family = AF_INET;
   server.sin_port = htons(9999);   //assigning 9999 as port address
   server.sin_addr.s_addr = INADDR_ANY;
   bzero(&server.sin_zero, 8);
  
   //binding to the port
   if( bind(sock,(struct sockaddr *)&server, sockaddr_len) == -1)
   {
       perror("bind");
       exit(-1);
   }
  
  
   //listening for incoming connections
   if((listen(sock, 5)) == -1)
   {
       perror("listen");
       exit(-1);
   }
  
  
  
   while(1)
   {
         printf("Server is ready to talk.....\n");
  
        //accept the incoming connection
       if( (new = accept(sock, (struct sockaddr *)&client, &(sockaddr_len))) == -1)
       {
           perror("Listen");
           exit(-1);
       }
  
   data = 1;
  
  
   while(data)
   {
       data = recv(new, buffer, MAX, 0); //receiving message from client
      
       if(data)
       {
           send(new,buffer, data, 0);//sending the same message to client
           buffer[data] = '\0';
           printf("sent messg : %s\n",buffer);//printing the sent message
       }
      
      
   }
   printf("Client was disconnected\n\n");
   close(new); //closing the file descriptor
  
   }
}

Client Code:

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <errno.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define MAX 1024

int main(int argc, char *argv[])
{
  
    struct sockaddr_in remote_server;
    int sock;
    char input[MAX];
    char output[MAX];
    int len;

    //creating socket
    sock = socket(AF_INET, SOCK_STREAM, 0);

    //checking socket was created or not
    if(sock == -1)
    {
        perror("socket:");
        exit(-1);
    }
  
    //remote server details like port and ip address
    remote_server.sin_family = AF_INET;
    remote_server.sin_port = htons(9999);   //assigning 9999 as port address
    remote_server.sin_addr.s_addr = inet_addr(argv[1]); /*IP Address will be taken from command line argument*/
    bzero(&remote_server.sin_zero, 8);

    //connecting to remote server
    if( (connect(sock, (struct sockaddr *)&remote_server, sizeof(struct sockaddr_in))) == -1 )
    {
        perror("connect:");
        exit(-1);
    }

    while(printf("Client:") && fgets(input, MAX, stdin)!=NULL)
    {
      
        send(sock, input, strlen(input),0); //sending the message to server

        len = recv(sock, output, MAX,0);    //message received from server
        output[len] = '\0';
        printf("Server: %s\n",output); // printing the message received from the server
      
    }

    printf("\n");
    close(sock);    //closing the socket descriptor    
}