Function event_callback

components/net/lwip/lwip-2.1.2/src/api/sockets.c:2498–2583

* Callback registered in the netconn layer for each socket-netconn. * Processes recvevent (data available) and wakes up tasks waiting for select. * * @note for LWIP_TCPIP_CORE_LOCKING any caller of this function * must have the core lock held when signaling the following events * as they might cause select_list_cb to be checked: * NETCONN_EVT_RCVPLUS * NETCONN_EVT_SENDPLUS * NETCONN_

 * This requirement will be asserted in select_check_waiters()
 */
static void
event_callback(struct netconn *conn, enum netconn_evt evt, u16_t len)
{
  int s, check_waiters;
  struct lwip_sock *sock;
  SYS_ARCH_DECL_PROTECT(lev);

  LWIP_UNUSED_ARG(len);

  /* Get socket */
  if (conn) {
    s = conn->socket;
    if (s < 0) {
      /* Data comes in right away after an accept, even though
       * the server task might not have created a new socket yet.
       * Just count down (or up) if that's the case and we
       * will use the data later. Note that only receive events
       * can happen before the new socket is set up. */
      SYS_ARCH_PROTECT(lev);
      if (conn->socket < 0) {
        if (evt == NETCONN_EVT_RCVPLUS) {
          /* conn->socket is -1 on initialization
             lwip_accept adjusts sock->recvevent if conn->socket < -1 */
          conn->socket--;
        }
        SYS_ARCH_UNPROTECT(lev);
        return;
      }
      s = conn->socket;
      SYS_ARCH_UNPROTECT(lev);
    }

    sock = get_socket(s);
    if (!sock) {
      return;
    }
  } else {
    return;
  }

  check_waiters = 1;
  SYS_ARCH_PROTECT(lev);
  /* Set event as required */
  switch (evt) {
    case NETCONN_EVT_RCVPLUS:
      sock->rcvevent++;
      if (sock->rcvevent > 1) {
        check_waiters = 0;
      }
      break;
    case NETCONN_EVT_RCVMINUS:
      sock->rcvevent--;
      check_waiters = 0;
      break;
    case NETCONN_EVT_SENDPLUS:
      if (sock->sendevent) {
        check_waiters = 0;
      }