Function main

test/sockets/test_udp_echo.c:93–145

}

int main(void) {
  server_fd = socket(AF_INET, SOCK_DGRAM, 0);
  client_fd = socket(AF_INET, SOCK_DGRAM, 0);
  assert(server_fd >= 0 && client_fd >= 0);

  struct sockaddr_in addr;
  memset(&addr, 0, sizeof(addr));
  addr.sin_family = AF_INET;
  addr.sin_port = htons(0); // ephemeral
  inet_pton(AF_INET, "127.0.0.1", &addr.sin_addr);
  if (bind(server_fd, (struct sockaddr*)&addr, sizeof(addr)) != 0) {
    perror("bind");
    return 1;
  }

  // The OS-assigned ephemeral port must be readable synchronously.
  struct sockaddr_in la;
  socklen_t ll = sizeof(la);
  if (getsockname(server_fd, (struct sockaddr*)&la, &ll) != 0) {
    perror("getsockname");
    return 1;
  }
  assert(ntohs(la.sin_port) != 0);
  printf("listening on 127.0.0.1:%u\n", (unsigned)ntohs(la.sin_port));

  // Datagram socket options round-trip on the bound socket.
  int ttl = 64, on = 1, rcv = 131072, got;
  socklen_t gl = sizeof(got);
  assert(setsockopt(server_fd, IPPROTO_IP, IP_TTL, &ttl, sizeof(ttl)) == 0);
  assert(setsockopt(server_fd, SOL_SOCKET, SO_BROADCAST, &on, sizeof(on)) == 0);
  assert(setsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &rcv, sizeof(rcv)) == 0);
  assert(getsockopt(server_fd, IPPROTO_IP, IP_TTL, &got, &gl) == 0 && got == 64);
  assert(getsockopt(server_fd, SOL_SOCKET, SO_BROADCAST, &got, &gl) == 0 && got != 0);
  assert(getsockopt(server_fd, SOL_SOCKET, SO_RCVBUF, &got, &gl) == 0 && got > 0);

  set_nonblocking(server_fd);
  set_nonblocking(client_fd);

  memset(&dest, 0, sizeof(dest));
  dest.sin_family = AF_INET;
  dest.sin_port = la.sin_port;
  inet_pton(AF_INET, "127.0.0.1", &dest.sin_addr);

#ifdef __EMSCRIPTEN__
  emscripten_set_main_loop(main_loop, 0, 0);
#else
  while (1) {
    main_loop();
    usleep(1000);
  }
#endif
  return 0;
}