diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..6dc1654
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "lwip"]
+	path = lwip
+	url = git@github.com:lwip-tcpip/lwip.git
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2175ec2..f29b8f4 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -1,14 +1,13 @@
 cmake_minimum_required(VERSION 3.5)
 
 set(CMAKE_TRY_COMPILE_TARGET_TYPE "STATIC_LIBRARY")
-set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/arm-none-eabi-gcc.cmake)
+set(CMAKE_TOOLCHAIN_FILE ${CMAKE_SOURCE_DIR}/toolchain.cmake)
 
 enable_language(C ASM)
 set(CMAKE_C_STANDARD 11)
 set(CMAKE_C_STANDARD_REQUIRED ON)
 set(CMAKE_C_EXTENSIONS OFF)
 
-#Output directory
 set (CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_SOURCE_DIR}/build)
 
 project(stm32)
diff --git a/lwip b/lwip
new file mode 160000
index 0000000..d0efd9e
--- /dev/null
+++ b/lwip
@@ -0,0 +1 @@
+Subproject commit d0efd9ef7ba08e54b46b1060e2b4629a4907391b
diff --git a/arm-none-eabi-gcc.cmake b/toolchain.cmake
similarity index 95%
rename from arm-none-eabi-gcc.cmake
rename to toolchain.cmake
index 58841e7..c0f982a 100644
--- a/arm-none-eabi-gcc.cmake
+++ b/toolchain.cmake
@@ -30,4 +30,5 @@ set(CMAKE_SIZE_UTIL ${ARM_TOOLCHAIN_DIR}/${TOOLCHAIN_PREFIX}size CACHE INTERNAL
 set(CMAKE_FIND_ROOT_PATH ${BINUTILS_PATH})
 set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
 set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
-set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
\ No newline at end of file
+set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+