Function accept_function

components/net/lwip/lwip-2.1.2/src/api/api_msg.c:532–599

* Accept callback function for TCP netconns. * Allocates a new netconn and posts that to conn->acceptmbox. * * @see tcp.h (struct tcp_pcb_listen.accept) for parameters and return value */

 * @see tcp.h (struct tcp_pcb_listen.accept) for parameters and return value
 */
static err_t
accept_function(void *arg, struct tcp_pcb *newpcb, err_t err)
{
  struct netconn *newconn;
  struct netconn *conn = (struct netconn *)arg;

  if (conn == NULL) {
    return ERR_VAL;
  }
  if (!NETCONN_MBOX_VALID(conn, &conn->acceptmbox)) {
    LWIP_DEBUGF(API_MSG_DEBUG, ("accept_function: acceptmbox already deleted\n"));
    return ERR_VAL;
  }

  if (newpcb == NULL) {
    /* out-of-pcbs during connect: pass on this error to the application */
    if (sys_mbox_trypost(&conn->acceptmbox, lwip_netconn_err_to_msg(ERR_ABRT)) == ERR_OK) {
      /* Register event with callback */
      API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
    }
    return ERR_VAL;
  }
  LWIP_ASSERT("expect newpcb == NULL or err == ERR_OK", err == ERR_OK);
  LWIP_UNUSED_ARG(err); /* for LWIP_NOASSERT */

  LWIP_DEBUGF(API_MSG_DEBUG, ("accept_function: newpcb->state: %s\n", tcp_debug_state_str(newpcb->state)));

  /* We have to set the callback here even though
   * the new socket is unknown. newconn->socket is marked as -1. */
  newconn = netconn_alloc(conn->type, conn->callback);
  if (newconn == NULL) {
    /* outof netconns: pass on this error to the application */
    if (sys_mbox_trypost(&conn->acceptmbox, lwip_netconn_err_to_msg(ERR_ABRT)) == ERR_OK) {
      /* Register event with callback */
      API_EVENT(conn, NETCONN_EVT_RCVPLUS, 0);
    }
    return ERR_MEM;
  }
  newconn->pcb.tcp = newpcb;
  setup_tcp(newconn);

  /* handle backlog counter */
  tcp_backlog_delayed(newpcb);

  if (sys_mbox_trypost(&conn->acceptmbox, newconn) != ERR_OK) {
    /* When returning != ERR_OK, the pcb is aborted in tcp_process(),
       so do nothing here! */
    /* remove all references to this netconn from the pcb */
    struct tcp_pcb *pcb = newconn->pcb.tcp;
    tcp_arg(pcb, NULL);
    tcp_recv(pcb, NULL);
    tcp_sent(pcb, NULL);
    tcp_poll(pcb, NULL, 0);
    tcp_err(pcb, NULL);
    /* remove reference from to the pcb from this netconn */
    newconn->pcb.tcp = NULL;
    /* no need to drain since we know the recvmbox is empty. */
    sys_mbox_free(&newconn->recvmbox);