#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <sys/socket.h>
#include <unistd.h>

int main() {
  struct sockaddr_in addr;
  addr.sin_family = AF_INET;         /* IPv4 */
  addr.sin_port = htons(8000);       /* Port */
  addr.sin_addr.s_addr = INADDR_ANY; /* equals to 0.0.0.0 */
  int sfd = socket(AF_INET, SOCK_STREAM, 0);
  if (sfd == -1) {
    perror("could not open socket");
    return 1;
  }
  int opt = 1;
  setsockopt(sfd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));
  int bind_addr = bind(sfd, (struct sockaddr *)&addr, sizeof(addr));
  if (bind_addr == -1) {
    perror("could not bind socket");
    return 1;
  }
  int listen_addr = listen(sfd, 100);
  if (listen_addr == -1) {
    perror("could not listen");
    return 1;
  }
  while (1) {
    int conn = accept(sfd, NULL, NULL);
    if (conn == -1) {
      perror("could not accept connection");
      return 1;
    }
    char buf[1024];
    ssize_t n = read(conn, buf, sizeof(buf));
    write(conn, buf, n);
    close(conn);
  }
  return 0;
}