Fix #27: Required to lock TCPIP core functionality

Ref:
- #27
- espressif/arduino-esp32#10526

src/AsyncTCP.cpp

@@ -39,6 +39,26 @@ extern "C"{
 #include <NetworkInterface.h>
 #endif
 
+#define TAG "AsyncTCP"
+
+// https://github.com/espressif/arduino-esp32/issues/10526
+#ifdef CONFIG_LWIP_TCPIP_CORE_LOCKING
+#define TCP_MUTEX_LOCK()                                \
+  if (!sys_thread_tcpip(LWIP_CORE_LOCK_QUERY_HOLDER)) { \
+    ESP_LOGE(TAG, "LOCK_TCPIP_CORE @ %s:%d", __FILE__, __LINE__); \
+    LOCK_TCPIP_CORE();                                  \
+  }
+
+#define TCP_MUTEX_UNLOCK()                             \
+  if (sys_thread_tcpip(LWIP_CORE_LOCK_QUERY_HOLDER)) { \
+    ESP_LOGE(TAG, "UNLOCK_TCPIP_CORE @ %s:%d", __FILE__, __LINE__); \
+    UNLOCK_TCPIP_CORE();                               \
+  }
+#else  // CONFIG_LWIP_TCPIP_CORE_LOCKING
+#define TCP_MUTEX_LOCK()
+#define TCP_MUTEX_UNLOCK()
+#endif  // CONFIG_LWIP_TCPIP_CORE_LOCKING
+
 #define INVALID_CLOSED_SLOT -1
 
 /*
@@ -722,17 +742,20 @@ bool AsyncClient::_connect(ip_addr_t addr, uint16_t port){
         return false;
     }
 
+    TCP_MUTEX_LOCK();
     tcp_pcb* pcb = tcp_new_ip_type(addr.type);
     if (!pcb){
+        TCP_MUTEX_UNLOCK();
         log_e("pcb == NULL");
         return false;
     }
-
     tcp_arg(pcb, this);
     tcp_err(pcb, &_tcp_error);
     tcp_recv(pcb, &_tcp_recv);
     tcp_sent(pcb, &_tcp_sent);
     tcp_poll(pcb, &_tcp_poll, 1);
+    TCP_MUTEX_UNLOCK();
+
     esp_err_t err =_tcp_connect(pcb, _closed_slot, &addr, port,(tcp_connected_fn)&_tcp_connected);
     return err == ESP_OK;
 }
@@ -1461,7 +1484,9 @@ void AsyncServer::begin(){
         return;
     }
     int8_t err;
+    TCP_MUTEX_LOCK();
     _pcb = tcp_new_ip_type(_bind4 && _bind6 ? IPADDR_TYPE_ANY : (_bind6 ? IPADDR_TYPE_V6 : IPADDR_TYPE_V4));
+    TCP_MUTEX_UNLOCK();
     if (!_pcb){
         log_e("_pcb == NULL");
         return;
@@ -1493,14 +1518,18 @@ void AsyncServer::begin(){
         log_e("listen_pcb == NULL");
         return;
     }
+    TCP_MUTEX_LOCK();
     tcp_arg(_pcb, (void*) this);
     tcp_accept(_pcb, &_s_accept);
+    TCP_MUTEX_UNLOCK();
 }
 
 void AsyncServer::end(){
     if(_pcb){
+        TCP_MUTEX_LOCK();
         tcp_arg(_pcb, NULL);
         tcp_accept(_pcb, NULL);
+        TCP_MUTEX_UNLOCK();
         if(tcp_close(_pcb) != ERR_OK){
             _tcp_abort(_pcb, -1);
         }