Rework JerryScript transport layer. (#2421)

Introducing jerryscript-debugger-transport.h interface, which allows
chaining multiple protocols (e.g. tcp and websocket).

JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com

14 files changed, 947 insertions, 387 deletions

diff --git a/jerry-core/api/jerry-debugger-transport.c b/jerry-core/api/jerry-debugger-transport.c
new file mode 100644
index 00000000..d4ba0a3d
--- /dev/null
+++ b/jerry-core/api/jerry-debugger-transport.c
@@ -0,0 +1,273 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "debugger.h"
+#include "jcontext.h"
+#include "jerryscript.h"
+
+#ifdef JERRY_DEBUGGER
+
+/**
+ * Minimum number of bytes transmitted or received.
+ */
+#define JERRY_DEBUGGER_TRANSPORT_MIN_BUFFER_SIZE 64
+
+/**
+ * Sleep time in milliseconds between each jerry_debugger_receive call
+ */
+#define JERRY_DEBUGGER_TRANSPORT_TIMEOUT 100
+
+/**
+ * Allocate memory for a connection.
+ *
+ * @return allocated memory on success
+ *         NULL otherwise
+ */
+void *
+jerry_debugger_transport_malloc (size_t size) /**< size of the memory block */
+{
+  return jmem_heap_alloc_block_null_on_error (size);
+} /* jerry_debugger_transport_malloc */
+
+/**
+ * Free memory allocated for a connection.
+ */
+void
+jerry_debugger_transport_free (void *mem_p, /**< value returned by jerry_debugger_transport_malloc() */
+                               size_t size) /**< same size passed to jerry_debugger_transport_malloc() */
+{
+  jmem_heap_free_block (mem_p, size);
+} /* jerry_debugger_transport_free */
+
+/**
+ * Add a new transport layer.
+ */
+void
+jerry_debugger_transport_add (jerry_debugger_transport_header_t *header_p, /**< transport implementation */
+                              size_t send_message_header_size, /**< header bytes reserved for outgoing messages */
+                              size_t max_send_message_size, /**< maximum number of bytes transmitted in a message */
+                              size_t receive_message_header_size, /**< header bytes reserved for incoming messages */
+                              size_t max_receive_message_size) /**< maximum number of bytes received in a message */
+{
+  JERRY_ASSERT (max_send_message_size > JERRY_DEBUGGER_TRANSPORT_MIN_BUFFER_SIZE
+                && max_receive_message_size > JERRY_DEBUGGER_TRANSPORT_MIN_BUFFER_SIZE);
+
+  header_p->next_p = JERRY_CONTEXT (debugger_transport_header_p);
+  JERRY_CONTEXT (debugger_transport_header_p) = header_p;
+
+  uint8_t *payload_p;
+  size_t max_send_size;
+  size_t max_receive_size;
+
+  if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
+  {
+    payload_p = JERRY_CONTEXT (debugger_send_buffer_payload_p);
+    max_send_size = JERRY_CONTEXT (debugger_max_send_size);
+    max_receive_size = JERRY_CONTEXT (debugger_max_receive_size);
+  }
+  else
+  {
+    JERRY_DEBUGGER_SET_FLAGS (JERRY_DEBUGGER_CONNECTED);
+    payload_p = JERRY_CONTEXT (debugger_send_buffer);
+    max_send_size = JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE;
+    max_receive_size = JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE;
+  }
+
+  JERRY_ASSERT (max_send_size > JERRY_DEBUGGER_TRANSPORT_MIN_BUFFER_SIZE + send_message_header_size);
+  JERRY_ASSERT (max_receive_size > JERRY_DEBUGGER_TRANSPORT_MIN_BUFFER_SIZE + receive_message_header_size);
+
+  JERRY_CONTEXT (debugger_send_buffer_payload_p) = payload_p + send_message_header_size;
+
+  max_send_size = max_send_size - send_message_header_size;
+  max_receive_size = max_receive_size - receive_message_header_size;
+
+  if (max_send_size > max_send_message_size)
+  {
+    max_send_size = max_send_message_size;
+  }
+
+  if (max_receive_size > max_receive_message_size)
+  {
+    max_receive_size = max_receive_message_size;
+  }
+
+  JERRY_CONTEXT (debugger_max_send_size) = (uint8_t) max_send_size;
+  JERRY_CONTEXT (debugger_max_receive_size) = (uint8_t) max_receive_size;
+} /* jerry_debugger_transport_add */
+
+/**
+ * Starts the communication to the debugger client.
+ * Must be called after the connection is successfully established.
+ */
+void
+jerry_debugger_transport_start (void)
+{
+  JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
+
+  if (jerry_debugger_send_configuration (JERRY_CONTEXT (debugger_max_receive_size)))
+  {
+    JERRY_DEBUGGER_SET_FLAGS (JERRY_DEBUGGER_VM_STOP);
+    JERRY_CONTEXT (debugger_stop_context) = NULL;
+  }
+} /* jerry_debugger_transport_start */
+
+/**
+ * Returns true if a debugger client is connected.
+ *
+ * @return true - a debugger client is connected,
+ *         false - otherwise
+ */
+bool
+jerry_debugger_transport_is_connected (void)
+{
+  return (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED) != 0;
+} /* jerry_debugger_transport_is_connected */
+
+/**
+ * Notifies the debugger server that the connection is closed.
+ */
+void
+jerry_debugger_transport_close (void)
+{
+  if (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED))
+  {
+    return;
+  }
+
+  jerry_debugger_transport_header_t *current_p = JERRY_CONTEXT (debugger_transport_header_p);
+
+  JERRY_ASSERT (current_p != NULL);
+
+  do
+  {
+    jerry_debugger_transport_header_t *next_p = current_p->next_p;
+
+    current_p->close (current_p);
+
+    current_p = next_p;
+  }
+  while (current_p != NULL);
+
+  JERRY_CONTEXT (debugger_flags) = JERRY_DEBUGGER_VM_IGNORE;
+
+  jerry_port_log (JERRY_LOG_LEVEL_DEBUG, "Debugger client connection closed.\n");
+
+  jerry_debugger_free_unreferenced_byte_code ();
+} /* jerry_debugger_transport_close */
+
+/**
+ * Send data over the current connection
+ *
+ * @return true - data sent successfully,
+ *         false - connection closed
+ */
+bool
+jerry_debugger_transport_send (const uint8_t *message_p, /**< message to be sent */
+                               size_t message_length) /**< message length in bytes */
+{
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
+  JERRY_ASSERT (message_length > 0);
+
+  jerry_debugger_transport_header_t *header_p = JERRY_CONTEXT (debugger_transport_header_p);
+  uint8_t *payload_p = JERRY_CONTEXT (debugger_send_buffer_payload_p);
+  size_t max_send_size = JERRY_CONTEXT (debugger_max_send_size);
+
+  do
+  {
+    size_t fragment_length = (message_length <= max_send_size ? message_length
+                                                              : max_send_size);
+
+    memcpy (payload_p, message_p, fragment_length);
+
+    if (!header_p->send (header_p, payload_p, fragment_length))
+    {
+      return false;
+    }
+
+    message_p += fragment_length;
+    message_length -= fragment_length;
+  }
+  while (message_length > 0);
+
+  return true;
+} /* jerry_debugger_transport_send */
+
+/**
+ * Receive data from the current connection
+ *
+ * Note:
+ *   A message is received if message_start_p is not NULL
+ *
+ * @return true - function successfully completed,
+ *         false - connection closed
+ */
+bool
+jerry_debugger_transport_receive (jerry_debugger_transport_receive_context_t *context_p) /**< [out] receive
+                                                                                          *   context */
+{
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
+
+  context_p->buffer_p = JERRY_CONTEXT (debugger_receive_buffer);
+  context_p->received_length = JERRY_CONTEXT (debugger_received_length);
+  context_p->message_p = NULL;
+  context_p->message_length = 0;
+  context_p->message_total_length = 0;
+
+  jerry_debugger_transport_header_t *header_p = JERRY_CONTEXT (debugger_transport_header_p);
+
+  return header_p->receive (header_p, context_p);
+} /* jerry_debugger_transport_receive */
+
+/**
+ * Clear the message buffer after the message is processed
+ */
+void
+jerry_debugger_transport_receive_completed (jerry_debugger_transport_receive_context_t *context_p) /**< receive
+                                                                                                    *   context */
+{
+  JERRY_ASSERT (context_p->message_p != NULL);
+  JERRY_ASSERT (context_p->buffer_p == JERRY_CONTEXT (debugger_receive_buffer));
+
+  size_t message_total_length = context_p->message_total_length;
+  size_t received_length = context_p->received_length;
+
+  JERRY_ASSERT (message_total_length <= received_length);
+
+  if (message_total_length == 0 || message_total_length == received_length)
+  {
+    /* All received data is processed. */
+    JERRY_CONTEXT (debugger_received_length) = 0;
+    return;
+  }
+
+  uint8_t *buffer_p = context_p->buffer_p;
+  received_length -= message_total_length;
+
+  memmove (buffer_p, buffer_p + message_total_length, received_length);
+
+  JERRY_CONTEXT (debugger_received_length) = (uint16_t) received_length;
+} /* jerry_debugger_transport_receive_completed */
+
+/**
+ * Suspend execution for a given time.
+ * Note: If the platform does not have nanosleep or usleep, this function does not sleep at all.
+ */
+void
+jerry_debugger_transport_sleep (void)
+{
+  jerry_port_sleep (JERRY_DEBUGGER_TRANSPORT_TIMEOUT);
+} /* jerry_debugger_transport_sleep */
+
+#endif /* JERRY_DEBUGGER */
diff --git a/jerry-core/api/jerry-debugger.c b/jerry-core/api/jerry-debugger.c
index 717ad840..22bca84d 100644
--- a/jerry-core/api/jerry-debugger.c
+++ b/jerry-core/api/jerry-debugger.c
@@ -16,6 +16,8 @@
 #include "debugger.h"
 #include "jcontext.h"
 #include "jerryscript.h"
+#include "debugger-tcp.h"
+#include "debugger-ws.h"
 
 /**
  * Checks whether the debugger is connected.
@@ -96,8 +98,14 @@ void
 jerry_debugger_init (uint16_t port) /**< server port number */
 {
 #ifdef JERRY_DEBUGGER
-  JERRY_CONTEXT (debugger_port) = port;
-  jerry_debugger_accept_connection ();
+  if (!jerry_debugger_tcp_create (port)
+      || !jerry_debugger_ws_create ())
+  {
+    jerry_debugger_transport_close ();
+    return;
+  }
+
+  jerry_debugger_transport_start ();
 #else /* !JERRY_DEBUGGER */
   JERRY_UNUSED (port);
 #endif /* JERRY_DEBUGGER */
@@ -173,7 +181,7 @@ jerry_debugger_wait_for_client_source (jerry_debugger_wait_for_source_callback_t
         }
       }
 
-      jerry_debugger_sleep ();
+      jerry_debugger_transport_sleep ();
     }
 
     JERRY_ASSERT (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CLIENT_SOURCE_MODE)
diff --git a/jerry-core/api/jerry.c b/jerry-core/api/jerry.c
index 622705fb..6a8f9166 100644
--- a/jerry-core/api/jerry.c
+++ b/jerry-core/api/jerry.c
@@ -35,6 +35,7 @@
 #include "ecma-typedarray-object.h"
 #include "jcontext.h"
 #include "jerryscript.h"
+#include "jerryscript-debugger-transport.h"
 #include "jmem.h"
 #include "js-parser.h"
 #include "re-compiler.h"
@@ -199,7 +200,7 @@ jerry_cleanup (void)
 #ifdef JERRY_DEBUGGER
   if (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED)
   {
-    jerry_debugger_close_connection ();
+    jerry_debugger_transport_close ();
   }
 #endif /* JERRY_DEBUGGER */
 
diff --git a/jerry-core/debugger/debugger-tcp.c b/jerry-core/debugger/debugger-tcp.c
new file mode 100644
index 00000000..7b80a530
--- /dev/null
+++ b/jerry-core/debugger/debugger-tcp.c
@@ -0,0 +1,237 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "debugger-tcp.h"
+#include "jrt.h"
+
+#ifdef JERRY_DEBUGGER
+
+#include <arpa/inet.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+/**
+ * Implementation of transport over tcp/ip.
+ */
+typedef struct
+{
+  jerry_debugger_transport_header_t header; /**< transport header */
+  int tcp_socket; /**< tcp socket */
+} jerry_debugger_transport_tcp_t;
+
+/**
+ * Log tcp error message.
+ */
+static void
+jerry_debugger_tcp_log_error (void)
+{
+  JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+} /* jerry_debugger_tcp_log_error */
+
+/**
+ * Close a tcp connection.
+ */
+static void
+jerry_debugger_tcp_close (jerry_debugger_transport_header_t *header_p) /**< tcp implementation */
+{
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
+
+  jerry_debugger_transport_tcp_t *tcp_p = (jerry_debugger_transport_tcp_t *) header_p;
+
+  JERRY_DEBUG_MSG ("TCP connection closed.\n");
+
+  close (tcp_p->tcp_socket);
+
+  jerry_debugger_transport_free ((void *) header_p, sizeof (jerry_debugger_transport_tcp_t));
+} /* jerry_debugger_tcp_close */
+
+/**
+ * Send data over a tcp connection.
+ *
+ * @return true - if the data has been sent successfully
+ *         false - otherwise
+ */
+static bool
+jerry_debugger_tcp_send (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
+                         uint8_t *message_p, /**< message to be sent */
+                         size_t message_length) /**< message length in bytes */
+{
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
+
+  jerry_debugger_transport_tcp_t *tcp_p = (jerry_debugger_transport_tcp_t *) header_p;
+
+  do
+  {
+    ssize_t sent_bytes = send (tcp_p->tcp_socket, message_p, message_length, 0);
+
+    if (sent_bytes < 0)
+    {
+      if (errno == EWOULDBLOCK)
+      {
+        continue;
+      }
+
+      jerry_debugger_tcp_log_error ();
+      jerry_debugger_transport_close ();
+      return false;
+    }
+
+    message_p += sent_bytes;
+    message_length -= (size_t) sent_bytes;
+  }
+  while (message_length > 0);
+
+  return true;
+} /* jerry_debugger_tcp_send */
+
+/**
+ * Receive data from a tcp connection.
+ */
+static bool
+jerry_debugger_tcp_receive (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
+                            jerry_debugger_transport_receive_context_t *receive_context_p) /**< receive context */
+{
+  jerry_debugger_transport_tcp_t *tcp_p = (jerry_debugger_transport_tcp_t *) header_p;
+
+  uint8_t *buffer_p = receive_context_p->buffer_p + receive_context_p->received_length;
+  size_t buffer_size = JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE - receive_context_p->received_length;
+
+  ssize_t length = recv (tcp_p->tcp_socket, buffer_p, buffer_size, 0);
+
+  if (length < 0)
+  {
+    if (errno != EWOULDBLOCK)
+    {
+      jerry_debugger_tcp_log_error ();
+      jerry_debugger_transport_close ();
+      return false;
+    }
+    length = 0;
+  }
+
+  receive_context_p->received_length += (size_t) length;
+
+  if (receive_context_p->received_length > 0)
+  {
+    receive_context_p->message_p = receive_context_p->buffer_p;
+    receive_context_p->message_length = receive_context_p->received_length;
+  }
+
+  return true;
+} /* jerry_debugger_tcp_receive */
+
+/**
+ * Create a tcp connection.
+ *
+ * @return true if successful,
+ *         false otherwise
+ */
+bool
+jerry_debugger_tcp_create (uint16_t port) /**< listening port */
+{
+  int server_socket;
+  struct sockaddr_in addr;
+  socklen_t sin_size = sizeof (struct sockaddr_in);
+
+  addr.sin_family = AF_INET;
+  addr.sin_port = htons (port);
+  addr.sin_addr.s_addr = INADDR_ANY;
+
+  if ((server_socket = socket (AF_INET, SOCK_STREAM, 0)) == -1)
+  {
+    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+    return false;
+  }
+
+  int opt_value = 1;
+
+  if (setsockopt (server_socket, SOL_SOCKET, SO_REUSEADDR, &opt_value, sizeof (int)) == -1)
+  {
+    close (server_socket);
+    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+    return false;
+  }
+
+  if (bind (server_socket, (struct sockaddr *)&addr, sizeof (struct sockaddr)) == -1)
+  {
+    close (server_socket);
+    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+    return false;
+  }
+
+  if (listen (server_socket, 1) == -1)
+  {
+    close (server_socket);
+    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+    return false;
+  }
+
+  JERRY_DEBUG_MSG ("Waiting for client connection\n");
+
+  int tcp_socket = accept (server_socket, (struct sockaddr *)&addr, &sin_size);
+
+  close (server_socket);
+
+  if (tcp_socket == -1)
+  {
+    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+    return false;
+  }
+
+  /* Set non-blocking mode. */
+  int socket_flags = fcntl (tcp_socket, F_GETFL, 0);
+
+  if (socket_flags < 0)
+  {
+    close (tcp_socket);
+    return false;
+  }
+
+  if (fcntl (tcp_socket, F_SETFL, socket_flags | O_NONBLOCK) == -1)
+  {
+    close (tcp_socket);
+    return false;
+  }
+
+  JERRY_DEBUG_MSG ("Connected from: %s\n", inet_ntoa (addr.sin_addr));
+
+  size_t size = sizeof (jerry_debugger_transport_tcp_t);
+
+  jerry_debugger_transport_header_t *header_p;
+  header_p = (jerry_debugger_transport_header_t *) jerry_debugger_transport_malloc (size);
+
+  if (!header_p)
+  {
+    close (tcp_socket);
+    return false;
+  }
+
+  header_p->close = jerry_debugger_tcp_close;
+  header_p->send = jerry_debugger_tcp_send;
+  header_p->receive = jerry_debugger_tcp_receive;
+
+  ((jerry_debugger_transport_tcp_t *) header_p)->tcp_socket = tcp_socket;
+
+  jerry_debugger_transport_add (header_p,
+                                0,
+                                JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE,
+                                0,
+                                JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE);
+
+  return true;
+} /* jerry_debugger_tcp_create */
+
+#endif /* JERRY_DEBUGGER */
diff --git a/jerry-core/debugger/debugger-tcp.h b/jerry-core/debugger/debugger-tcp.h
new file mode 100644
index 00000000..a6d11aa8
--- /dev/null
+++ b/jerry-core/debugger/debugger-tcp.h
@@ -0,0 +1,27 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef DEBUGGER_TCP_H
+#define DEBUGGER_TCP_H
+
+#include "jerryscript-debugger-transport.h"
+
+#ifdef JERRY_DEBUGGER
+
+bool jerry_debugger_tcp_create (uint16_t port);
+
+#endif /* JERRY_DEBUGGER */
+
+#endif /* !DEBUGGER_TCP_H */
diff --git a/jerry-core/debugger/debugger-ws.c b/jerry-core/debugger/debugger-ws.c
index 0f12a693..d980b9b7 100644
--- a/jerry-core/debugger/debugger-ws.c
+++ b/jerry-core/debugger/debugger-ws.c
@@ -13,17 +13,11 @@
  * limitations under the License.
  */
 
-#include "debugger.h"
-#include "jcontext.h"
-#include "jerryscript-port.h"
+#include "debugger-ws.h"
+#include "jrt.h"
 
 #ifdef JERRY_DEBUGGER
 
-#include <arpa/inet.h>
-#include <errno.h>
-#include <fcntl.h>
-#include <unistd.h>
-
 /* JerryScript debugger protocol is a simplified version of RFC-6455 (WebSockets). */
 
 /**
@@ -62,12 +56,6 @@
 #define JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX 125
 
 /**
- * Waiting for data from the client.
- */
-#define JERRY_DEBUGGER_RECEIVE_DATA_MODE \
-  (JERRY_DEBUGGER_BREAKPOINT_MODE | JERRY_DEBUGGER_CLIENT_SOURCE_MODE)
-
-/**
  * WebSocket opcode types.
  */
 typedef enum
@@ -87,65 +75,7 @@ typedef struct
   uint8_t ws_opcode; /**< websocket opcode */
   uint8_t size; /**< size of the message */
   uint8_t mask[4]; /**< mask bytes */
-} jerry_debugger_receive_header_t;
-
-/**
- * Close the socket connection to the client.
- */
-static void
-jerry_debugger_close_connection_tcp (bool log_error) /**< log error */
-{
-  JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
-
-  JERRY_CONTEXT (debugger_flags) = JERRY_DEBUGGER_VM_IGNORE;
-
-  if (log_error)
-  {
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
-  }
-
-  JERRY_DEBUG_MSG ("Debugger client connection closed.\n");
-
-  close (JERRY_CONTEXT (debugger_connection));
-  JERRY_CONTEXT (debugger_connection) = -1;
-
-  jerry_debugger_free_unreferenced_byte_code ();
-} /* jerry_debugger_close_connection_tcp */
-
-/**
- * Send message to the client side.
- *
- * @return true - if the data was sent successfully to the client side
- *         false - otherwise
- */
-static bool
-jerry_debugger_send_tcp (const uint8_t *data_p, /**< data pointer */
-                         size_t data_size) /**< data size */
-{
-  JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
-
-  do
-  {
-    ssize_t sent_bytes = send (JERRY_CONTEXT (debugger_connection), data_p, data_size, 0);
-
-    if (sent_bytes < 0)
-    {
-      if (errno == EWOULDBLOCK)
-      {
-        continue;
-      }
-
-      jerry_debugger_close_connection_tcp (true);
-      return false;
-    }
-
-    data_size -= (size_t) sent_bytes;
-    data_p += sent_bytes;
-  }
-  while (data_size > 0);
-
-  return true;
-} /* jerry_debugger_send_tcp */
+} jerry_websocket_receive_header_t;
 
 /**
  * Convert a 6-bit value to a Base64 character.
@@ -213,8 +143,7 @@ jerry_to_base64 (const uint8_t *source_p, /**< source data */
  *         false - otherwise
  */
 static bool
-jerry_process_handshake (int client_socket, /**< client socket */
-                         uint8_t *request_buffer_p) /**< temporary buffer */
+jerry_process_handshake (uint8_t *request_buffer_p) /**< temporary buffer */
 {
   size_t request_buffer_size = 1024;
   uint8_t *request_end_p = request_buffer_p;
@@ -222,23 +151,33 @@ jerry_process_handshake (int client_socket, /**< client socket */
   /* Buffer request text until the double newlines are received. */
   while (true)
   {
-    size_t length = request_buffer_size - 1u - (size_t) (request_end_p - request_buffer_p);
-
-    if (length == 0)
+    jerry_debugger_transport_receive_context_t context;
+    if (!jerry_debugger_transport_receive (&context))
     {
-      JERRY_ERROR_MSG ("Handshake buffer too small.\n");
+      JERRY_ASSERT (!jerry_debugger_transport_is_connected ());
       return false;
     }
 
-    ssize_t size = recv (client_socket, request_end_p, length, 0);
+    if (context.message_p == NULL)
+    {
+      jerry_debugger_transport_sleep ();
+      continue;
+    }
+
+    size_t length = request_buffer_size - 1u - (size_t) (request_end_p - request_buffer_p);
 
-    if (size < 0)
+    if (length < context.message_length)
     {
-      JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
+      JERRY_ERROR_MSG ("Handshake buffer too small.\n");
       return false;
     }
 
-    request_end_p += (size_t) size;
+    /* Both stream and datagram packets are supported. */
+    memcpy (request_end_p, context.message_p, context.message_length);
+
+    jerry_debugger_transport_receive_completed (&context);
+
+    request_end_p += (size_t) context.message_length;
     *request_end_p = 0;
 
     if (request_end_p > request_buffer_p + 4
@@ -319,293 +258,194 @@ jerry_process_handshake (int client_socket, /**< client socket */
 
   text_p = "HTTP/1.1 101 Switching Protocols\r\nUpgrade: websocket\r\nConnection: Upgrade\r\nSec-WebSocket-Accept: ";
 
-  if (!jerry_debugger_send_tcp ((const uint8_t *) text_p, strlen (text_p))
-      || !jerry_debugger_send_tcp (request_buffer_p + sha1_length + 1, 27))
+  if (!jerry_debugger_transport_send ((const uint8_t *) text_p, strlen (text_p))
+      || !jerry_debugger_transport_send (request_buffer_p + sha1_length + 1, 27))
   {
     return false;
   }
 
   text_p = "=\r\n\r\n";
-  return jerry_debugger_send_tcp ((const uint8_t *) text_p, strlen (text_p));
+  return jerry_debugger_transport_send ((const uint8_t *) text_p, strlen (text_p));
 } /* jerry_process_handshake */
 
 /**
- * Initialize the socket connection.
- *
- * @return true - if the connection succeeded
- *         false - otherwise
+ * Close a tcp connection.
  */
-bool
-jerry_debugger_accept_connection (void)
+static void
+jerry_debugger_ws_close (jerry_debugger_transport_header_t *header_p) /**< tcp implementation */
 {
-  int server_socket;
-  struct sockaddr_in addr;
-  socklen_t sin_size = sizeof (struct sockaddr_in);
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
 
-  uint8_t *payload_p = JERRY_CONTEXT (debugger_send_buffer) + JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE;
-  JERRY_CONTEXT (debugger_send_buffer_payload_p) = payload_p;
+  jerry_debugger_transport_free ((void *) header_p, sizeof (jerry_debugger_transport_header_t));
+} /* jerry_debugger_ws_close */
 
-  uint8_t max_send_size = (JERRY_DEBUGGER_MAX_BUFFER_SIZE - JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE);
-  if (max_send_size > JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX)
-  {
-    max_send_size = JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX;
-  }
-  JERRY_CONTEXT (debugger_max_send_size) = max_send_size;
-
-  uint8_t receive_header_size = (JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE + JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE);
-  uint8_t max_receive_size = (uint8_t) (JERRY_DEBUGGER_MAX_BUFFER_SIZE - receive_header_size);
+/**
+ * Send data over a websocket connection.
+ *
+ * @return true - if the data has been sent successfully
+ *         false - otherwise
+ */
+static bool
+jerry_debugger_ws_send (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
+                        uint8_t *message_p, /**< message to be sent */
+                        size_t message_length) /**< message length in bytes */
+{
+  JERRY_ASSERT (message_length <= JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
 
-  if (max_receive_size > JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX)
-  {
-    max_receive_size = JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX;
-  }
-  JERRY_CONTEXT (debugger_max_receive_size) = max_receive_size;
+  message_p[-2] = JERRY_DEBUGGER_WEBSOCKET_FIN_BIT | JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME;
+  message_p[-1] = (uint8_t) message_length;
 
-  addr.sin_family = AF_INET;
-  addr.sin_port = htons (JERRY_CONTEXT (debugger_port));
-  addr.sin_addr.s_addr = INADDR_ANY;
+  return header_p->next_p->send (header_p->next_p, message_p - 2, message_length + 2);
+} /* jerry_debugger_ws_send */
 
-  if ((server_socket = socket (AF_INET, SOCK_STREAM, 0)) == -1)
+/**
+ * Receive data from a websocket connection.
+ */
+static bool
+jerry_debugger_ws_receive (jerry_debugger_transport_header_t *header_p, /**< tcp implementation */
+                           jerry_debugger_transport_receive_context_t *receive_context_p) /**< receive context */
+{
+  if (!header_p->next_p->receive (header_p->next_p, receive_context_p))
   {
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
     return false;
   }
 
-  int opt_value = 1;
-
-  if (setsockopt (server_socket, SOL_SOCKET, SO_REUSEADDR, &opt_value, sizeof (int)) == -1)
+  if (receive_context_p->message_p == NULL)
   {
-    close (server_socket);
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
-    return false;
+    return true;
   }
 
-  if (bind (server_socket, (struct sockaddr *)&addr, sizeof (struct sockaddr)) == -1)
-  {
-    close (server_socket);
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
-    return false;
-  }
+  size_t message_total_length = receive_context_p->message_total_length;
 
-  if (listen (server_socket, 1) == -1)
+  if (message_total_length == 0)
   {
-    close (server_socket);
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
-    return false;
+    /* Byte stream. */
+    if (receive_context_p->message_length < sizeof (jerry_websocket_receive_header_t))
+    {
+      receive_context_p->message_p = NULL;
+      return true;
+    }
   }
-
-  JERRY_DEBUG_MSG ("Waiting for client connection\n");
-
-  JERRY_CONTEXT (debugger_connection) = accept (server_socket, (struct sockaddr *)&addr, &sin_size);
-
-  if (JERRY_CONTEXT (debugger_connection) == -1)
+  else
   {
-    close (server_socket);
-    JERRY_ERROR_MSG ("Error: %s\n", strerror (errno));
-    return false;
+    /* Datagram packet. */
+    JERRY_ASSERT (receive_context_p->message_length >= sizeof (jerry_websocket_receive_header_t));
   }
 
-  close (server_socket);
-
-  JERRY_DEBUGGER_SET_FLAGS (JERRY_DEBUGGER_CONNECTED);
-
-  bool is_handshake_ok = false;
-
-  JMEM_DEFINE_LOCAL_ARRAY (request_buffer_p, 1024, uint8_t);
+  uint8_t *message_p = receive_context_p->message_p;
 
-  is_handshake_ok = jerry_process_handshake (JERRY_CONTEXT (debugger_connection),
-                                             request_buffer_p);
-
-  JMEM_FINALIZE_LOCAL_ARRAY (request_buffer_p);
-
-  if (!is_handshake_ok)
+  if ((message_p[0] & ~JERRY_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRY_DEBUGGER_WEBSOCKET_FIN_BIT
+      || (message_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK) > JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX
+      || !(message_p[1] & JERRY_DEBUGGER_WEBSOCKET_MASK_BIT))
   {
-    jerry_debugger_close_connection ();
+    JERRY_ERROR_MSG ("Unsupported Websocket message.\n");
+    jerry_debugger_transport_close ();
     return false;
   }
 
-  if (!jerry_debugger_send_configuration (max_receive_size))
+  if ((message_p[0] & JERRY_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME)
   {
+    JERRY_ERROR_MSG ("Unsupported Websocket opcode.\n");
+    jerry_debugger_transport_close ();
     return false;
   }
 
-  /* Set non-blocking mode. */
-  int socket_flags = fcntl (JERRY_CONTEXT (debugger_connection), F_GETFL, 0);
+  size_t message_length = (size_t) (message_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK);
 
-  if (socket_flags < 0)
+  if (message_total_length == 0)
   {
-    jerry_debugger_close_connection_tcp (true);
-    return false;
-  }
+    size_t new_total_length = message_length + sizeof (jerry_websocket_receive_header_t);
 
-  if (fcntl (JERRY_CONTEXT (debugger_connection), F_SETFL, socket_flags | O_NONBLOCK) == -1)
+    /* Byte stream. */
+    if (receive_context_p->message_length < new_total_length)
+    {
+      receive_context_p->message_p = NULL;
+      return true;
+    }
+
+    receive_context_p->message_total_length = new_total_length;
+  }
+  else
   {
-    jerry_debugger_close_connection_tcp (true);
-    return false;
+    /* Datagram packet. */
+    JERRY_ASSERT (receive_context_p->message_length == (message_length + sizeof (jerry_websocket_receive_header_t)));
   }
 
-  JERRY_DEBUG_MSG ("Connected from: %s\n", inet_ntoa (addr.sin_addr));
+  message_p += sizeof (jerry_websocket_receive_header_t);
 
-  JERRY_DEBUGGER_SET_FLAGS (JERRY_DEBUGGER_VM_STOP);
-  JERRY_CONTEXT (debugger_stop_context) = NULL;
+  receive_context_p->message_p = message_p;
+  receive_context_p->message_length = message_length;
 
-  return true;
-} /* jerry_debugger_accept_connection */
+  /* Unmask data bytes. */
+  const uint8_t *mask_p = message_p - JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE;
+  const uint8_t *mask_end_p = message_p;
+  const uint8_t *message_end_p = message_p + message_length;
 
-/**
- * Close the socket connection to the client.
- */
-inline void JERRY_ATTR_ALWAYS_INLINE
-jerry_debugger_close_connection (void)
-{
-  jerry_debugger_close_connection_tcp (false);
-} /* jerry_debugger_close_connection */
+  while (message_p < message_end_p)
+  {
+    /* Invert certain bits with xor operation. */
+    *message_p = *message_p ^ *mask_p;
 
-/**
- * Send message to the client side
- *
- * @return true - if the data was sent successfully to the debugger client,
- *         false - otherwise
- */
-bool
-jerry_debugger_send (size_t data_size) /**< data size */
-{
-  JERRY_ASSERT (data_size <= JERRY_CONTEXT (debugger_max_send_size));
+    message_p++;
+    mask_p++;
 
-  uint8_t *header_p = JERRY_CONTEXT (debugger_send_buffer);
-  header_p[0] = JERRY_DEBUGGER_WEBSOCKET_FIN_BIT | JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME;
-  header_p[1] = (uint8_t) data_size;
+    if (JERRY_UNLIKELY (mask_p >= mask_end_p))
+    {
+      mask_p -= JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE;
+    }
+  }
 
-  return jerry_debugger_send_tcp (header_p, data_size + JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE);
-} /* jerry_debugger_send */
+  return true;
+} /* jerry_debugger_ws_receive */
 
 /**
- * Receive message from the client.
- *
- * Note:
- *   If the function returns with true, the value of
- *   JERRY_DEBUGGER_VM_STOP flag should be ignored.
+ * Initialize the websocket transportation layer.
  *
- * @return true - if execution should be resumed,
+ * @return true - if the connection succeeded
  *         false - otherwise
  */
 bool
-jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p) /**< [out] data received from client */
+jerry_debugger_ws_create (void)
 {
-  JERRY_ASSERT (JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED);
-  JERRY_ASSERT (JERRY_CONTEXT (debugger_max_receive_size) <= JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
-
-  JERRY_ASSERT (message_data_p != NULL ? !!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE)
-                                       : !(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE));
-
-  JERRY_CONTEXT (debugger_message_delay) = JERRY_DEBUGGER_MESSAGE_FREQUENCY;
+  bool is_handshake_ok = false;
 
-  uint8_t *recv_buffer_p = JERRY_CONTEXT (debugger_receive_buffer);
-  bool resume_exec = false;
-  uint8_t expected_message_type = 0;
+  const size_t buffer_size = 1024;
+  uint8_t *request_buffer_p = (uint8_t *) jerry_debugger_transport_malloc (buffer_size);
 
-  while (true)
+  if (!request_buffer_p)
   {
-    uint32_t offset = JERRY_CONTEXT (debugger_receive_buffer_offset);
-
-    ssize_t byte_recv = recv (JERRY_CONTEXT (debugger_connection),
-                              recv_buffer_p + offset,
-                              JERRY_DEBUGGER_MAX_BUFFER_SIZE - offset,
-                              0);
-
-    if (byte_recv < 0)
-    {
-      if (errno != EWOULDBLOCK)
-      {
-        jerry_debugger_close_connection_tcp (true);
-        return true;
-      }
-
-      byte_recv = 0;
-    }
-
-    offset += (uint32_t) byte_recv;
-    JERRY_CONTEXT (debugger_receive_buffer_offset) = (uint16_t) offset;
-
-    if (offset < sizeof (jerry_debugger_receive_header_t))
-    {
-      if (expected_message_type != 0)
-      {
-        continue;
-      }
-
-      return resume_exec;
-    }
-
-    if ((recv_buffer_p[0] & ~JERRY_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRY_DEBUGGER_WEBSOCKET_FIN_BIT
-        || (recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK) > JERRY_CONTEXT (debugger_max_receive_size)
-        || !(recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_MASK_BIT))
-    {
-      JERRY_ERROR_MSG ("Unsupported Websocket message.\n");
-      jerry_debugger_close_connection ();
-      return true;
-    }
-
-    if ((recv_buffer_p[0] & JERRY_DEBUGGER_WEBSOCKET_OPCODE_MASK) != JERRY_DEBUGGER_WEBSOCKET_BINARY_FRAME)
-    {
-      JERRY_ERROR_MSG ("Unsupported Websocket opcode.\n");
-      jerry_debugger_close_connection ();
-      return true;
-    }
-
-    uint32_t message_size = (uint32_t) (recv_buffer_p[1] & JERRY_DEBUGGER_WEBSOCKET_LENGTH_MASK);
-    uint32_t message_total_size = (uint32_t) (message_size + sizeof (jerry_debugger_receive_header_t));
-
-    if (offset < message_total_size)
-    {
-      if (expected_message_type != 0)
-      {
-        continue;
-      }
+    return false;
+  }
 
-      return resume_exec;
-    }
+  is_handshake_ok = jerry_process_handshake (request_buffer_p);
 
-    /* Unmask data bytes. */
-    uint8_t *data_p = recv_buffer_p + sizeof (jerry_debugger_receive_header_t);
-    const uint8_t *mask_p = data_p - JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE;
-    const uint8_t *mask_end_p = data_p;
-    const uint8_t *data_end_p = data_p + message_size;
+  jerry_debugger_transport_free ((void *) request_buffer_p, buffer_size);
 
-    while (data_p < data_end_p)
-    {
-      /* Invert certain bits with xor operation. */
-      *data_p = *data_p ^ *mask_p;
+  if (!is_handshake_ok && jerry_debugger_transport_is_connected ())
+  {
+    return false;
+  }
 
-      data_p++;
-      mask_p++;
+  const size_t interface_size = sizeof (jerry_debugger_transport_header_t);
+  jerry_debugger_transport_header_t *header_p;
+  header_p = (jerry_debugger_transport_header_t *) jerry_debugger_transport_malloc (interface_size);
 
-      if (mask_p >= mask_end_p)
-      {
-        mask_p -= JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE;
-      }
-    }
+  if (!header_p)
+  {
+    return false;
+  }
 
-    /* The jerry_debugger_process_message function is inlined
-     * so passing these arguments is essentially free. */
-    if (!jerry_debugger_process_message (recv_buffer_p + sizeof (jerry_debugger_receive_header_t),
-                                         message_size,
-                                         &resume_exec,
-                                         &expected_message_type,
-                                         message_data_p))
-    {
-      return true;
-    }
+  header_p->close = jerry_debugger_ws_close;
+  header_p->send = jerry_debugger_ws_send;
+  header_p->receive = jerry_debugger_ws_receive;
 
-    if (message_total_size < offset)
-    {
-      memmove (recv_buffer_p,
-               recv_buffer_p + message_total_size,
-               offset - message_total_size);
-    }
+  jerry_debugger_transport_add (header_p,
+                                JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE,
+                                JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX,
+                                JERRY_DEBUGGER_WEBSOCKET_HEADER_SIZE + JERRY_DEBUGGER_WEBSOCKET_MASK_SIZE,
+                                JERRY_DEBUGGER_WEBSOCKET_ONE_BYTE_LEN_MAX);
 
-    JERRY_CONTEXT (debugger_receive_buffer_offset) = (uint16_t) (offset - message_total_size);
-  }
-} /* jerry_debugger_receive */
+  return true;
+} /* jerry_debugger_ws_create */
 
 #endif /* JERRY_DEBUGGER */
diff --git a/jerry-core/debugger/debugger-ws.h b/jerry-core/debugger/debugger-ws.h
index 3a7c97c8..7be74bf1 100644
--- a/jerry-core/debugger/debugger-ws.h
+++ b/jerry-core/debugger/debugger-ws.h
@@ -16,39 +16,13 @@
 #ifndef DEBUGGER_WS_H
 #define DEBUGGER_WS_H
 
-#include "ecma-globals.h"
+#include "jerryscript-debugger-transport.h"
 
 #ifdef JERRY_DEBUGGER
 
 /* JerryScript debugger protocol is a simplified version of RFC-6455 (WebSockets). */
 
-/**
- * Maximum number of bytes transmitted or received.
- */
-#define JERRY_DEBUGGER_MAX_BUFFER_SIZE 128
-
-/**
- * Incoming message: next message of string data.
- */
-typedef struct
-{
-  uint8_t type; /**< type of the message */
-} jerry_debugger_receive_uint8_data_part_t;
-
-/**
- * Byte data for evaluating expressions and receiving client source.
- */
-typedef struct
-{
-  uint32_t uint8_size; /**< total size of the client source */
-  uint32_t uint8_offset; /**< current offset in the client source */
-} jerry_debugger_uint8_data_t;
-
-bool jerry_debugger_accept_connection (void);
-void jerry_debugger_close_connection (void);
-
-bool jerry_debugger_send (size_t data_size);
-bool jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p);
+bool jerry_debugger_ws_create (void);
 
 void jerry_debugger_compute_sha1 (const uint8_t *input1, size_t input1_len,
                                   const uint8_t *input2, size_t input2_len,
diff --git a/jerry-core/debugger/debugger.c b/jerry-core/debugger/debugger.c
index a3591ad7..26b52d59 100644
--- a/jerry-core/debugger/debugger.c
+++ b/jerry-core/debugger/debugger.c
@@ -20,11 +20,20 @@
 #include "ecma-eval.h"
 #include "ecma-objects.h"
 #include "jcontext.h"
+#include "jerryscript-port.h"
 #include "lit-char-helpers.h"
 
 #ifdef JERRY_DEBUGGER
 
 /**
+ * Incoming message: next message of string data.
+ */
+typedef struct
+{
+  uint8_t type; /**< type of the message */
+} jerry_debugger_receive_uint8_data_part_t;
+
+/**
  * The number of message types in the debugger should reflect the
  * debugger versioning.
  */
@@ -34,6 +43,12 @@ JERRY_STATIC_ASSERT (JERRY_DEBUGGER_MESSAGES_OUT_MAX_COUNT == 27
                      debugger_version_correlates_to_message_type_count);
 
 /**
+ * Waiting for data from the client.
+ */
+#define JERRY_DEBUGGER_RECEIVE_DATA_MODE \
+  (JERRY_DEBUGGER_BREAKPOINT_MODE | JERRY_DEBUGGER_CLIENT_SOURCE_MODE)
+
+/**
  * Type cast the debugger send buffer into a specific type.
  */
 #define JERRY_DEBUGGER_SEND_BUFFER_AS(type, name_p) \
@@ -71,10 +86,27 @@ jerry_debugger_free_unreferenced_byte_code (void)
 } /* jerry_debugger_free_unreferenced_byte_code */
 
 /**
+ * Send data over an active connection.
+ *
+ * @return true - if the data was sent successfully
+ *         false - otherwise
+ */
+static bool
+jerry_debugger_send (size_t message_length) /**< message length in bytes */
+{
+  JERRY_ASSERT (message_length <= JERRY_CONTEXT (debugger_max_send_size));
+
+  jerry_debugger_transport_header_t *header_p = JERRY_CONTEXT (debugger_transport_header_p);
+  uint8_t *payload_p = JERRY_CONTEXT (debugger_send_buffer_payload_p);
+
+  return header_p->send (header_p, payload_p, message_length);
+} /* jerry_debugger_send */
+
+/**
  * Send backtrace.
  */
 static void
-jerry_debugger_send_backtrace (uint8_t *recv_buffer_p) /**< pointer to the received data */
+jerry_debugger_send_backtrace (const uint8_t *recv_buffer_p) /**< pointer to the received data */
 {
   JERRY_DEBUGGER_RECEIVE_BUFFER_AS (jerry_debugger_receive_get_backtrace_t, get_backtrace_p);
 
@@ -244,23 +276,13 @@ jerry_debugger_send_eval (const lit_utf8_byte_t *eval_string_p, /**< evaluated s
 } /* jerry_debugger_send_eval */
 
 /**
- * Suspend execution for a given time.
- * Note: If the platform does not have nanosleep or usleep, this function does not sleep at all.
- */
-void
-jerry_debugger_sleep (void)
-{
-  jerry_port_sleep (JERRY_DEBUGGER_TIMEOUT);
-} /* jerry_debugger_sleep */
-
-/**
  * Check received packet size.
  */
 #define JERRY_DEBUGGER_CHECK_PACKET_SIZE(type) \
   if (message_size != sizeof (type)) \
   { \
     JERRY_ERROR_MSG ("Invalid message size\n"); \
-    jerry_debugger_close_connection (); \
+    jerry_debugger_transport_close (); \
     return false; \
   }
 
@@ -270,8 +292,8 @@ jerry_debugger_sleep (void)
  * @return true - if message is processed successfully
  *         false - otherwise
  */
-inline bool JERRY_ATTR_ALWAYS_INLINE
-jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the received data */
+static inline bool JERRY_ATTR_ALWAYS_INLINE
+jerry_debugger_process_message (const uint8_t *recv_buffer_p, /**< pointer to the received data */
                                 uint32_t message_size, /**< message size */
                                 bool *resume_exec_p, /**< pointer to the resume exec flag */
                                 uint8_t *expected_message_type_p, /**< message type */
@@ -283,7 +305,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       && !(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_BREAKPOINT_MODE))
   {
     JERRY_ERROR_MSG ("Message requires breakpoint mode\n");
-    jerry_debugger_close_connection ();
+    jerry_debugger_transport_close ();
     return false;
   }
 
@@ -298,7 +320,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
     {
       jmem_heap_free_block (uint8_data_p, uint8_data_p->uint8_size + sizeof (jerry_debugger_uint8_data_t));
       JERRY_ERROR_MSG ("Unexpected message\n");
-      jerry_debugger_close_connection ();
+      jerry_debugger_transport_close ();
       return false;
     }
 
@@ -308,7 +330,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
     {
       jmem_heap_free_block (uint8_data_p, uint8_data_p->uint8_size + sizeof (jerry_debugger_uint8_data_t));
       JERRY_ERROR_MSG ("Invalid message size\n");
-      jerry_debugger_close_connection ();
+      jerry_debugger_transport_close ();
       return false;
     }
 
@@ -320,7 +342,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
     {
       jmem_heap_free_block (uint8_data_p, uint8_data_p->uint8_size + sizeof (jerry_debugger_uint8_data_t));
       JERRY_ERROR_MSG ("Invalid message size\n");
-      jerry_debugger_close_connection ();
+      jerry_debugger_transport_close ();
       return false;
     }
 
@@ -370,7 +392,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (byte_code_free_cp != JERRY_CONTEXT (debugger_byte_code_free_tail))
       {
         JERRY_ERROR_MSG ("Invalid byte code free order\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -531,7 +553,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_PARSER_WAIT_MODE))
       {
         JERRY_ERROR_MSG ("Not in parser wait mode\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -544,7 +566,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (message_size < sizeof (jerry_debugger_receive_eval_first_t) + 1)
       {
         JERRY_ERROR_MSG ("Invalid message size\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -558,7 +580,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
         if (eval_size != message_size - sizeof (jerry_debugger_receive_eval_first_t))
         {
           JERRY_ERROR_MSG ("Invalid message size\n");
-          jerry_debugger_close_connection ();
+          jerry_debugger_transport_close ();
           return false;
         }
 
@@ -594,14 +616,14 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (message_size <= sizeof (jerry_debugger_receive_client_source_first_t))
       {
         JERRY_ERROR_MSG ("Invalid message size\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
       if (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CLIENT_SOURCE_MODE))
       {
         JERRY_ERROR_MSG ("Not in client source mode\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -616,7 +638,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
           && client_source_size != message_size - header_size)
       {
         JERRY_ERROR_MSG ("Invalid message size\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -653,7 +675,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CLIENT_SOURCE_MODE))
       {
         JERRY_ERROR_MSG ("Not in client source mode\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -671,7 +693,7 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
       if (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CLIENT_SOURCE_MODE))
       {
         JERRY_ERROR_MSG ("Not in client source mode\n");
-        jerry_debugger_close_connection ();
+        jerry_debugger_transport_close ();
         return false;
       }
 
@@ -687,12 +709,75 @@ jerry_debugger_process_message (uint8_t *recv_buffer_p, /**< pointer to the rece
     default:
     {
       JERRY_ERROR_MSG ("Unexpected message.");
-      jerry_debugger_close_connection ();
+      jerry_debugger_transport_close ();
       return false;
     }
   }
 } /* jerry_debugger_process_message */
 
+/**
+ * Receive message from the client.
+ *
+ * Note:
+ *   If the function returns with true, the value of
+ *   JERRY_DEBUGGER_VM_STOP flag should be ignored.
+ *
+ * @return true - if execution should be resumed,
+ *         false - otherwise
+ */
+bool
+jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p) /**< [out] data received from client */
+{
+  JERRY_ASSERT (jerry_debugger_transport_is_connected ());
+
+  JERRY_ASSERT (message_data_p != NULL ? !!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE)
+                                       : !(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_RECEIVE_DATA_MODE));
+
+  JERRY_CONTEXT (debugger_message_delay) = JERRY_DEBUGGER_MESSAGE_FREQUENCY;
+
+  bool resume_exec = false;
+  uint8_t expected_message_type = 0;
+
+  while (true)
+  {
+    jerry_debugger_transport_receive_context_t context;
+    if (!jerry_debugger_transport_receive (&context))
+    {
+      JERRY_ASSERT (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED));
+      return true;
+    }
+
+    if (context.message_p == NULL)
+    {
+      if (expected_message_type != 0)
+      {
+        jerry_debugger_transport_sleep ();
+        continue;
+      }
+
+      return resume_exec;
+    }
+
+    /* Only datagram packets are supported. */
+    JERRY_ASSERT (context.message_total_length > 0);
+
+    /* The jerry_debugger_process_message function is inlined
+     * so passing these arguments is essentially free. */
+    if (!jerry_debugger_process_message (context.message_p,
+                                         (uint32_t) context.message_length,
+                                         &resume_exec,
+                                         &expected_message_type,
+                                         message_data_p))
+    {
+      JERRY_ASSERT (!(JERRY_CONTEXT (debugger_flags) & JERRY_DEBUGGER_CONNECTED));
+      return true;
+    }
+
+    jerry_debugger_transport_receive_completed (&context);
+  }
+} /* jerry_debugger_receive */
+
+
 #undef JERRY_DEBUGGER_CHECK_PACKET_SIZE
 
 /**
@@ -727,7 +812,7 @@ jerry_debugger_breakpoint_hit (uint8_t message_type) /**< message type */
 
   while (!jerry_debugger_receive (&uint8_data))
   {
-    jerry_debugger_sleep ();
+    jerry_debugger_transport_sleep ();
   }
 
   if (uint8_data != NULL)
diff --git a/jerry-core/debugger/debugger.h b/jerry-core/debugger/debugger.h
index 40239438..7321f5b3 100644
--- a/jerry-core/debugger/debugger.h
+++ b/jerry-core/debugger/debugger.h
@@ -18,6 +18,7 @@
 
 #include "debugger-ws.h"
 #include "ecma-globals.h"
+#include "jerryscript-debugger-transport.h"
 
 #ifdef JERRY_DEBUGGER
 
@@ -34,22 +35,17 @@
 #define JERRY_DEBUGGER_MESSAGE_FREQUENCY 5
 
 /**
- * Sleep time in milliseconds between each jerry_debugger_receive call
+ * This constant represents that the string to be sent has no subtype.
  */
-#define JERRY_DEBUGGER_TIMEOUT 100
-
-/**
-  * This constant represents that the string to be sent has no subtype.
-  */
 #define JERRY_DEBUGGER_NO_SUBTYPE 0
 
 /**
  * Limited resources available for the engine, so it is important to
  * check the maximum buffer size. It needs to be between 64 and 256 bytes.
  */
-#if JERRY_DEBUGGER_MAX_BUFFER_SIZE < 64 || JERRY_DEBUGGER_MAX_BUFFER_SIZE > 256
+#if JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE < 64 || JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE > 256
 #error Please define the MAX_BUFFER_SIZE between 64 and 256 bytes.
-#endif /* JERRY_DEBUGGER_MAX_BUFFER_SIZE < 64 || JERRY_DEBUGGER_MAX_BUFFER_SIZE > 256 */
+#endif /* JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE < 64 || JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE > 256 */
 
 /**
  * Calculate the maximum number of items for a given type
@@ -227,6 +223,15 @@ typedef enum
 } jerry_debugger_output_subtype_t;
 
 /**
+ * Byte data for evaluating expressions and receiving client source.
+ */
+typedef struct
+{
+  uint32_t uint8_size; /**< total size of the client source */
+  uint32_t uint8_offset; /**< current offset in the client source */
+} jerry_debugger_uint8_data_t;
+
+/**
  * Delayed free of byte code data.
  */
 typedef struct
@@ -400,11 +405,8 @@ typedef struct
 
 void jerry_debugger_free_unreferenced_byte_code (void);
 
-void jerry_debugger_sleep (void);
+bool jerry_debugger_receive (jerry_debugger_uint8_data_t **message_data_p);
 
-bool jerry_debugger_process_message (uint8_t *recv_buffer_p, uint32_t message_size,
-                                     bool *resume_exec_p, uint8_t *expected_message_p,
-                                     jerry_debugger_uint8_data_t **message_data_p);
 void jerry_debugger_breakpoint_hit (uint8_t message_type);
 
 void jerry_debugger_send_type (jerry_debugger_header_type_t type);
diff --git a/jerry-core/include/jerryscript-debugger-transport.h b/jerry-core/include/jerryscript-debugger-transport.h
new file mode 100644
index 00000000..24e4e853
--- /dev/null
+++ b/jerry-core/include/jerryscript-debugger-transport.h
@@ -0,0 +1,107 @@
+/* Copyright JS Foundation and other contributors, http://js.foundation
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef JERRYSCRIPT_DEBUGGER_TRANSPORT_H
+#define JERRYSCRIPT_DEBUGGER_TRANSPORT_H
+
+#include <jerryscript-core.h>
+
+#ifdef __cplusplus
+extern "C"
+{
+#endif /* __cplusplus */
+
+/** \addtogroup jerry-debugger-transport Jerry engine debugger interface - transport control
+ * @{
+ */
+
+/**
+ * Maximum number of bytes transmitted or received.
+ */
+#define JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE 128
+
+/**
+ * Receive message context.
+ */
+typedef struct
+{
+  uint8_t *buffer_p; /**< buffer for storing the received data */
+  size_t received_length; /**< number of currently received bytes */
+  uint8_t *message_p; /**< start of the received message */
+  size_t message_length; /**< length of the received message */
+  size_t message_total_length; /**< total length for datagram protocols,
+                                *   0 for stream protocols */
+} jerry_debugger_transport_receive_context_t;
+
+/**
+ * Forward definition of jerry_debugger_transport_header_t.
+ */
+struct jerry_debugger_transport_interface_t;
+
+/**
+ * Close connection callback.
+ */
+typedef void (*jerry_debugger_transport_close_t) (struct jerry_debugger_transport_interface_t *header_p);
+
+/**
+ * Send data callback.
+ */
+typedef bool (*jerry_debugger_transport_send_t) (struct jerry_debugger_transport_interface_t *header_p,
+                                                 uint8_t *message_p, size_t message_length);
+
+/**
+ * Receive data callback.
+ */
+typedef bool (*jerry_debugger_transport_receive_t) (struct jerry_debugger_transport_interface_t *header_p,
+                                                    jerry_debugger_transport_receive_context_t *context_p);
+
+/**
+ * Transport layer header.
+ */
+typedef struct jerry_debugger_transport_interface_t
+{
+  /* The following fields must be filled before calling jerry_debugger_transport_add(). */
+  jerry_debugger_transport_close_t close; /**< close connection callback */
+  jerry_debugger_transport_send_t send;  /**< send data callback */
+  jerry_debugger_transport_receive_t receive; /**< receive data callback */
+
+  /* The following fields are filled by jerry_debugger_transport_add(). */
+  struct jerry_debugger_transport_interface_t *next_p; /**< next transport layer */
+} jerry_debugger_transport_header_t;
+
+void * jerry_debugger_transport_malloc (size_t size);
+void jerry_debugger_transport_free (void *mem_p, size_t size);
+void jerry_debugger_transport_add (jerry_debugger_transport_header_t *header_p,
+                                   size_t send_message_header_size, size_t max_send_message_size,
+                                   size_t receive_message_header_size, size_t max_receive_message_size);
+void jerry_debugger_transport_start (void);
+
+bool jerry_debugger_transport_is_connected (void);
+void jerry_debugger_transport_close (void);
+
+bool jerry_debugger_transport_send (const uint8_t *message_p, size_t message_length);
+bool jerry_debugger_transport_receive (jerry_debugger_transport_receive_context_t *context_p);
+void jerry_debugger_transport_receive_completed (jerry_debugger_transport_receive_context_t *context_p);
+
+void jerry_debugger_transport_sleep (void);
+
+/**
+ * @}
+ */
+
+#ifdef __cplusplus
+}
+#endif /* __cplusplus */
+#endif /* !JERRYSCRIPT_DEBUGGER_TRANSPORT_H */
diff --git a/jerry-core/include/jerryscript-debugger.h b/jerry-core/include/jerryscript-debugger.h
index c6e73a79..a111c6b6 100644
--- a/jerry-core/include/jerryscript-debugger.h
+++ b/jerry-core/include/jerryscript-debugger.h
@@ -16,7 +16,7 @@
 #ifndef JERRYSCRIPT_DEBUGGER_H
 #define JERRYSCRIPT_DEBUGGER_H
 
-#include <stdbool.h>
+#include <jerryscript-core.h>
 
 #ifdef __cplusplus
 extern "C"
diff --git a/jerry-core/jcontext/jcontext.h b/jerry-core/jcontext/jcontext.h
index f1abe682..e98d4511 100644
--- a/jerry-core/jcontext/jcontext.h
+++ b/jerry-core/jcontext/jcontext.h
@@ -27,6 +27,7 @@
 #include "re-bytecode.h"
 #include "vm-defines.h"
 #include "jerryscript.h"
+#include "jerryscript-debugger-transport.h"
 
 /** \addtogroup context Context
  * @{
@@ -109,19 +110,18 @@ typedef struct
 #endif /* JERRY_VM_EXEC_STOP */
 
 #ifdef JERRY_DEBUGGER
-  uint8_t debugger_send_buffer[JERRY_DEBUGGER_MAX_BUFFER_SIZE]; /**< buffer for sending messages */
-  uint8_t debugger_receive_buffer[JERRY_DEBUGGER_MAX_BUFFER_SIZE]; /**< buffer for receiving messages */
+  uint8_t debugger_send_buffer[JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE]; /**< buffer for sending messages */
+  uint8_t debugger_receive_buffer[JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE]; /**< buffer for receiving messages */
+  jerry_debugger_transport_header_t *debugger_transport_header_p; /**< head of transport protocol chain */
   uint8_t *debugger_send_buffer_payload_p; /**< start where the outgoing message can be written */
   vm_frame_ctx_t *debugger_stop_context; /**< stop only if the current context is equal to this context */
   jmem_cpointer_t debugger_byte_code_free_head; /**< head of byte code free linked list */
   jmem_cpointer_t debugger_byte_code_free_tail; /**< tail of byte code free linked list */
   uint32_t debugger_flags; /**< debugger flags */
-  uint16_t debugger_receive_buffer_offset; /**< receive buffer offset */
-  uint16_t debugger_port; /**< debugger socket communication port */
+  uint16_t debugger_received_length; /**< length of currently received bytes */
   uint8_t debugger_message_delay; /**< call receive message when reaches zero */
-  uint8_t debugger_max_send_size; /**< maximum amount of data that can be written */
+  uint8_t debugger_max_send_size; /**< maximum amount of data that can be sent */
   uint8_t debugger_max_receive_size; /**< maximum amount of data that can be received */
-  int debugger_connection; /**< holds the file descriptor of the socket communication */
 #endif /* JERRY_DEBUGGER */
 
 #ifdef JERRY_ENABLE_LINE_INFO
diff --git a/jerry-core/parser/js/js-parser-internal.h b/jerry-core/parser/js/js-parser-internal.h
index 52ba022d..fd7e5405 100644
--- a/jerry-core/parser/js/js-parser-internal.h
+++ b/jerry-core/parser/js/js-parser-internal.h
@@ -232,6 +232,13 @@ typedef struct
 {
   uint32_t value;                             /**< line or offset of the breakpoint */
 } parser_breakpoint_info_t;
+
+/**
+ * Maximum number of breakpoint info.
+ */
+#define PARSER_MAX_BREAKPOINT_INFO_COUNT \
+  (JERRY_DEBUGGER_TRANSPORT_MAX_BUFFER_SIZE / sizeof (parser_breakpoint_info_t))
+
 #endif /* JERRY_DEBUGGER */
 
 /**
@@ -316,8 +323,7 @@ typedef struct
 #endif /* PARSER_DUMP_BYTE_CODE */
 
 #ifdef JERRY_DEBUGGER
-  /** extra data for each breakpoint */
-  parser_breakpoint_info_t breakpoint_info[JERRY_DEBUGGER_MAX_BUFFER_SIZE / sizeof (parser_breakpoint_info_t)];
+  parser_breakpoint_info_t breakpoint_info[PARSER_MAX_BREAKPOINT_INFO_COUNT]; /**< breakpoint info list */
   uint16_t breakpoint_info_count; /**< current breakpoint index */
   parser_line_counter_t last_breakpoint_line; /**< last line where breakpoint has been inserted */
 #endif /* JERRY_DEBUGGER */
diff --git a/jerry-core/parser/js/js-parser.c b/jerry-core/parser/js/js-parser.c
index df4e61d0..bb191a9b 100644
--- a/jerry-core/parser/js/js-parser.c
+++ b/jerry-core/parser/js/js-parser.c
@@ -2949,7 +2949,7 @@ parser_parse_script (const uint8_t *arg_list_p, /**< function argument list */
         break;
       }
 
-      jerry_debugger_sleep ();
+      jerry_debugger_transport_sleep ();
     }
   }
 #endif /* JERRY_DEBUGGER */