Server Client program in C using sockets and tcp - c

Question

I have written a program for simple text chatting between server and client using socket programming. The server side runs okay since it's listening but when I run the client side program it runs but shows no output, meaning nothing shows up on server side if I type in Client side. Why am I not getting any response from Client side?
/****************** CLIENT CODE ****************/
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
int main(){
int clientSocket,n;
char buffer[256];
struct sockaddr_in serverAddr;
socklen_t addr_size;
/*---- Create the socket. The three arguments are: ----*/
/* 1) Internet domain 2) Stream socket 3) Default protocol (TCP in this case) */
clientSocket = socket(PF_INET, SOCK_STREAM, 0);
/*---- Configure settings of the server address struct ----*/
/* Address family = Internet */
serverAddr.sin_family = AF_INET;
/* Set port number, using htons function to use proper byte order */
serverAddr.sin_port = htons(7891);
/* Set IP address to localhost */
serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
/* Set all bits of the padding field to 0 */
memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);
/*---- Connect the socket to the server using the address struct ----*/
addr_size = sizeof serverAddr;
connect(clientSocket, (struct sockaddr *) &serverAddr, addr_size);
if (connect(clientSocket,(struct sockaddr *) &serverAddr,sizeof(serverAddr)) < 0)
error("ERROR connecting");
printf("Please enter the message: ");
bzero(buffer,256);
fgets(buffer,255,stdin);
n = write(clientSocket,buffer,strlen(buffer));
if (n < 0)
error("ERROR writing to socket");
bzero(buffer,256);
n = read(clientSocket,buffer,255);
if (n < 0)
error("ERROR reading from socket");
printf("%s\n",buffer);
close(clientSocket);
/*---- Read the message from the server into the buffer ----*/
//recv(clientSocket, buffer, 1024, 0);
/*---- Print the received message ----*/
//printf("Data received: %s",buffer);
return 0;
}
/****************** SERVER CODE ****************/
#include <stdio.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <string.h>
int main(){
int welcomeSocket, newSocket;
char buffer[256];
int n;
struct sockaddr_in serverAddr;
struct sockaddr_storage serverStorage;
socklen_t addr_size;
/*---- Create the socket. The three arguments are: ----*/
/* 1) Internet domain 2) Stream socket 3) Default protocol (TCP in this case) */
welcomeSocket = socket(PF_INET, SOCK_STREAM, 0);
/*---- Configure settings of the server address struct ----*/
/* Address family = Internet */
serverAddr.sin_family = AF_INET;
/* Set port number, using htons function to use proper byte order */
serverAddr.sin_port = htons(7891);
/* Set IP address to localhost */
serverAddr.sin_addr.s_addr = inet_addr("127.0.0.1");
/* Set all bits of the padding field to 0 */
memset(serverAddr.sin_zero, '\0', sizeof serverAddr.sin_zero);
/*---- Bind the address struct to the socket ----*/
bind(welcomeSocket, (struct sockaddr *) &serverAddr, sizeof(serverAddr));
/*---- Listen on the socket, with 5 max connection requests queued ----*/
if(listen(welcomeSocket,5)==0)
printf("Listening\n");
else
printf("Error\n");
/*---- Accept call creates a new socket for the incoming connection ----*/
addr_size = sizeof serverStorage;
newSocket = accept(welcomeSocket, (struct sockaddr *) &serverStorage, &addr_size);
/*---- Send message to the socket of the incoming connection ----*/
bzero(buffer,256);
n = read(welcomeSocket,buffer,255);
if (n < 0) error("ERROR reading from socket");
printf("Here is the message: %s\n",buffer);
n = write(welcomeSocket,"I got your message",18);
if (n < 0) error("ERROR reading from socket");
printf("Here is the message: %s\n",buffer);
n = write(welcomeSocket,"I got your message",18);
if (n < 0) error("ERROR writing to socket");
close(newSocket);
close(welcomeSocket);
return 0;
}

Answer 1

In your server code the read() should use the socket descriptor returned from the accept() not from the call to socket(). So try reading using newSocket rather than welcomeSocket.
n = read(newSocket,buffer,255);