[components/net/at]修复大数据量传输socket断开后可能丢数据的问题

components/net/at/at_socket/at_socket.c

@@ -1065,13 +1065,6 @@ int at_recvfrom(int socket, void *mem, size_t len, int flags, struct sockaddr *f
 
     while (1)
     {
-        if (sock->state == AT_SOCKET_CLOSED)
-        {
-            /* socket passively closed, receive function return 0 */
-            result = 0;
-            goto __exit;
-        }
-
         /* receive packet list last transmission of remaining data */
         rt_mutex_take(sock->recv_lock, RT_WAITING_FOREVER);
         recv_len = at_recvpkt_get(&(sock->recvpkt_list), (char *)mem, len);
@@ -1086,6 +1079,13 @@ int at_recvfrom(int socket, void *mem, size_t len, int flags, struct sockaddr *f
             goto __exit;
         }
 
+        if (sock->state == AT_SOCKET_CLOSED)
+        {
+            /* socket passively closed, receive function return 0 */
+            result = 0;
+            goto __exit;
+        }
+
         if (flags & MSG_DONTWAIT)
         {
             rt_set_errno(EAGAIN);