diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7b9b420b5..d890ef5cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -277,6 +277,7 @@ set(SOURCES
 	lib/parsers.c
 	lib/context.c
 	lib/sha-1.c
+	lib/alloc.c
 	)
 
 if (NOT LWS_WITHOUT_CLIENT)
diff --git a/lib/alloc.c b/lib/alloc.c
new file mode 100644
index 000000000..3bc5260ee
--- /dev/null
+++ b/lib/alloc.c
@@ -0,0 +1,30 @@
+#include "private-libwebsockets.h"
+
+static void *_realloc(void *ptr, size_t size)
+{
+	if (size)
+		return realloc(ptr, size);
+	else if (ptr)
+		free(ptr);
+	return NULL;
+}
+
+void *(*_lws_realloc)(void *ptr, size_t size) = _realloc;
+
+void *lws_realloc(void *ptr, size_t size)
+{
+	return _lws_realloc(ptr, size);
+}
+
+void *lws_zalloc(size_t size)
+{
+	void *ptr = _lws_realloc(NULL, size);
+	if (ptr)
+		memset(ptr, 0, size);
+	return ptr;
+}
+
+void lws_set_allocator(void *(*cb)(void *ptr, size_t size))
+{
+	_lws_realloc = cb;
+}
diff --git a/lib/libwebsockets.h b/lib/libwebsockets.h
index 0713b18f2..ff0ca338f 100644
--- a/lib/libwebsockets.h
+++ b/lib/libwebsockets.h
@@ -1337,6 +1337,12 @@ libwebsocket_read(struct libwebsocket_context *context,
 LWS_VISIBLE LWS_EXTERN struct libwebsocket_extension *libwebsocket_get_internal_extensions();
 #endif
 
+/*
+ * custom allocator support
+ */
+LWS_VISIBLE LWS_EXTERN void
+lws_set_allocator(void *(*realloc)(void *ptr, size_t size));
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/lib/private-libwebsockets.h b/lib/private-libwebsockets.h
index f053ae769..6fb16680c 100755
--- a/lib/private-libwebsockets.h
+++ b/lib/private-libwebsockets.h
@@ -1157,6 +1157,18 @@ lws_ssl_capable_write_no_ssl(struct libwebsocket *wsi, unsigned char *buf, int l
 #define lws_handshake_server(_a, _b, _c, _d) (0)
 #endif
 
+/*
+ * custom allocator
+ */
+LWS_EXTERN void*
+lws_realloc(void *ptr, size_t size);
+
+LWS_EXTERN void*
+lws_zalloc(size_t size);
+
+#define lws_malloc(S)	lws_realloc(NULL, S)
+#define lws_free(P)	lws_realloc(P, 0)
+
 /*
  * lws_plat_
  */