#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <assert.h>
#include <arpa/inet.h>
#include <sys/socket.h>

#define BUFLEN 512
#define PORT 1234

int main(void)
{
  int ret;

  int sock = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
  if (sock == -1) {
    perror("socket");
    return -1;
  }

  struct sockaddr_in sockaddr = {0};
  sockaddr.sin_family = AF_INET;
  sockaddr.sin_port = htons(PORT);
  sockaddr.sin_addr.s_addr = htonl(INADDR_ANY);

  ret = bind(sock, (struct sockaddr *)&sockaddr, (sizeof (struct sockaddr_in)));
  if (ret == -1) {
    perror("bind");
    return -1;
  }

  char buf[BUFLEN];

  while (1) {
    printf("Wait for datagram\n");

    struct sockaddr_in src_addr = {0};
    socklen_t addrlen = (sizeof (struct sockaddr_in));

    ssize_t recv_len = recvfrom(sock, buf, BUFLEN, 0, (struct sockaddr *)&src_addr, &addrlen);
    if (recv_len == -1) {
      perror("recvfrom");
      return -1;
    }

    buf[recv_len] = 0;
    printf("Received packet from %s:%d\n", inet_ntoa(src_addr.sin_addr), ntohs(src_addr.sin_port));
    printf("Data: %s\n", buf);

    /*
    //now reply the client with the same data
    if (sendto(s, buf, recv_len, 0, (struct sockaddr*) &si_other, slen) == -1) {
      die("sendto()");
    }
    */
  }

  close(sock);

  return 0;
}