My TCP socket server not sending and receiving - c

Question

I am trying to write a TCP socket server for a client then i ran into some problems. The server is not sending/receiving data. However, it can listen to and accept new clients.
I have tried "nc 127.0.0.1 -l 10001" to test the client and it works well. The server at one time could send and receive but encoded characters. I made some modifications and since then i have been seeing errors.
The exit Message can be commented or remove as it was declared in custom.h.
Any idea will be appreciated.
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <arpa/inet.h>
#include <netinet/in.h>
#include "custom.h"
#define PORT 10001
#define MAXIMUM_CONNECTION 20
#define DATA_SIZE 100
int main()
{
int sock = socket(PF_INET, SOCK_STREAM, IPPROTO_TCP);
struct sockaddr_in serverAddr, clientAddr;
memset(&serverAddr, '\0', sizeof(serverAddr));
serverAddr.sin_family = AF_INET;
serverAddr.sin_port = htons(PORT);
serverAddr.sin_addr.s_addr = htonl(INADDR_ANY);
if(bind(sock, (struct sockaddr *) &serverAddr, sizeof(serverAddr)) < 0) {
exitMessage("Failed to address to port");
}
if(listen(sock, MAXIMUM_CONNECTION) < 0) {
exitMessage("Server is deaf could not listen to incoming messages");
}
char buffer[DATA_SIZE], data[DATA_SIZE];
while(1) {
memset(buffer, '\0', DATA_SIZE);
memset(data, '\0', DATA_SIZE);
socklen_t clientAddrSize = sizeof(clientAddr);
if(accept(sock, (struct sockaddr *) &clientAddr, &clientAddrSize) < 0) {
exitMessage("Could not accept new connections");
}
if(recv(sock, buffer, DATA_SIZE - 1, 0) < 0) {
exitMessage("Failed to receive data from client");
}
printf("\nReceived: \'%s\' to client\n", buffer);
printf("input data for client: ");
int index = 0;
while((data[index++] = getchar()) != '\n');
if(send(sock, data, strlen(data), 0) < 0) {
exitMessage("Failed sending to client");
}
}
}

Answer 1

The socket you listen on is only for accepting new connections, not reading/writing data. The accept function returns a file descriptor for the accepted socket. That is the one you should be calling recv and send on.
int newsock;
if((newsock = accept(sock, (struct sockaddr *) &clientAddr, &clientAddrSize)) < 0) {
exitMessage("Could not accept new connections");
}
if(recv(newsock, buffer, DATA_SIZE - 1, 0) < 0) {
exitMessage("Failed to receive data from client");
}
printf("\nReceived: \'%s\' to client\n", buffer);
printf("input data for client: ");
int index = 0;
while((data[index++] = getchar()) != '\n');
if(send(newsock, data, strlen(data), 0) < 0) {
exitMessage("Failed sending to client");
}