Function lwip_accept

components/net/lwip/lwip-2.1.2/src/api/sockets.c:641–737

 */

int
lwip_accept(int s, struct sockaddr *addr, socklen_t *addrlen)
{
  struct lwip_sock *sock, *nsock;
  struct netconn *newconn;
  ip_addr_t naddr;
  u16_t port = 0;
  int newsock;
  err_t err;
  int recvevent;
  SYS_ARCH_DECL_PROTECT(lev);

  LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d)...\n", s));
  sock = get_socket(s);
  if (!sock) {
    return -1;
  }

  /* wait for a new connection */
  err = netconn_accept(sock->conn, &newconn);
  if (err != ERR_OK) {
    LWIP_DEBUGF(SOCKETS_DEBUG, ("lwip_accept(%d): netconn_acept failed, err=%d\n", s, err));
    if (NETCONNTYPE_GROUP(netconn_type(sock->conn)) != NETCONN_TCP) {
      sock_set_errno(sock, EOPNOTSUPP);
    } else if (err == ERR_CLSD) {
      sock_set_errno(sock, EINVAL);
    } else {
      sock_set_errno(sock, err_to_errno(err));
    }
    done_socket(sock);
    return -1;
  }
  LWIP_ASSERT("newconn != NULL", newconn != NULL);

  newsock = alloc_socket(newconn, 1);
  if (newsock == -1) {
    netconn_delete(newconn);
    sock_set_errno(sock, ENFILE);
    done_socket(sock);
    return -1;
  }
  LWIP_ASSERT("invalid socket index", (newsock >= LWIP_SOCKET_OFFSET) && (newsock < NUM_SOCKETS + LWIP_SOCKET_OFFSET));
  nsock = &sockets[newsock - LWIP_SOCKET_OFFSET];

  /* See event_callback: If data comes in right away after an accept, even
   * though the server task might not have created a new socket yet.
   * In that case, newconn->socket is counted down (newconn->socket--),
   * so nsock->rcvevent is >= 1 here!
   */
  SYS_ARCH_PROTECT(lev);
  recvevent = (s16_t)(-1 - newconn->socket);
  newconn->socket = newsock;
  SYS_ARCH_UNPROTECT(lev);

  if (newconn->callback) {
    LOCK_TCPIP_CORE();
    while (recvevent > 0) {
      recvevent--;