socket_srv.c

File contents

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

#define SRV_PORT 7777

int main() {
  int s_tcp, news;                  /* socket descriptor */
  struct sockaddr_in sa, sa_client; /* socket address structure*/
  socklen_t sa_len = sizeof(struct sockaddr_in);
  int n;
  char info[256];

  sa.sin_family = AF_INET; /* select IPv4 */
  sa.sin_port = htons(SRV_PORT);
  sa.sin_addr.s_addr = INADDR_ANY;

  if ((s_tcp = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP)) < 0) {
    perror("TCP Socket");
    exit(1);
  }

  if (bind(s_tcp, (struct sockaddr *)&sa, sa_len) < 0) {
    perror("bind");
    exit(1);
  }

  if (listen(s_tcp, 5) < 0) {
    perror("listen");
    close(s_tcp);
    exit(1);
  }
  printf("Waiting for TCP connections ... \n");

  while (1) {
    if ((news = accept(s_tcp, (struct sockaddr *)&sa_client, &sa_len)) < 0) {
      perror("accept");
      close(s_tcp);
      exit(1);
    }
    if (recv(news, info, sizeof(info), 0)) {
      printf("Message received: %s \n", info);
    }
  }

  close(s_tcp);
}