fix(mbedtls): Fix already freed and exception bug when ESP8266 as SSL/TLS server

internal gitlab: b216a729

Author: wujiangang

VERSION

@@ -19,4 +19,4 @@ phy:
 gitlab:
  driver : 68fc7b06
  lwip : 3267f12f
- mbedtls : 83e9034f
+ mbedtls : e4dace14

lib/libmbedtls.a

@@ -751,24 +751,30 @@ int lwip_close(int s)
  {
  return -1;
  }
-
-if (sock->conn->state != NETCONN_STATE_ERROR){
- tcp_recv(sock->conn->tcp, NULL);
- err = tcp_close(sock->conn->tcp);
-
- if (err != ERR_OK)
- {
- /* closing failed, try again later */
- tcp_recv(sock->conn->tcp, recv_tcp);
- return -1;
- } 
-}
+ /*Do not set callback function when tcp->state is LISTEN.
+ Avoid memory overlap when conn->tcp changes from
+ struct tcp_bcb to struct tcp_pcb_listen after lwip_listen.*/
+ if (sock->conn->tcp->state != LISTEN)
+ {
+ if (sock->conn->state != NETCONN_STATE_ERROR){
+ tcp_recv(sock->conn->tcp, NULL);
+ err = tcp_close(sock->conn->tcp);
 
-/* closing succeeded */
-remove_tcp(sock->conn);
-free_netconn(sock->conn);
-free_socket(sock);
-return ERR_OK;
+ if (err != ERR_OK)
+ {
+ /* closing failed, try again later */
+ tcp_recv(sock->conn->tcp, recv_tcp);
+ return -1;
+ }
+ }
+ /* closing succeeded */
+ remove_tcp(sock->conn);
+ } else {
+ tcp_close(sock->conn->tcp);
+ }
+ free_netconn(sock->conn);
+ free_socket(sock);
+ return ERR_OK;
 }
 
 int lwip_write(int s, const void *data, size_t size)