Moving I/O (aka communication) layer outside powHSM code (#189)

Moving I/O (aka communication) layer outside powHSM code

- The powHSM logic now handles only one command at a time
- Each implementation (i.e., Signer and TCPSigner) implement their own I/O and looping
- The communication module only facilitates access to the APDU buffer

firmware/src/hal/include/hal/communication.h

@@ -53,71 +53,4 @@ unsigned char *communication_get_msg_buffer();
  */
 size_t communication_get_msg_buffer_size();
 
-/**
- * @brief Exchanges bytes with the host. This function blocks until the host
- * sends a message.
- *
- *  The message exchanges data with the host using the msg_buffer. If there are
- * any bytes to transmit, they are transmitted first. After that the function
- * blocks until a new message is received from the host.
- *
- * @param tx The number of bytes sent to the host
- *
- * @returns the number of bytes received from the host
- */
-unsigned short communication_io_exchange(unsigned short tx);
-
-// BEGINNING of platform-dependent code
-#if defined(HSM_PLATFORM_X86)
-
-#include <stdio.h>
-
-/**
- * @brief For an external module processing
- * APDU messages
- *
- * @param cb the external module processing callback
- */
-typedef unsigned short (*communication_external_module_process_t)(
-    unsigned short tx);
-void communication_set_external_module_process(
-    communication_external_module_process_t cb);
-
-/**
- * @brief Starts a TCP server at the given host and port and sets it as the
- * channel on which communication_io_exchange will perform the IO operations
- * Either this or communication_set_input_file must be called before
- * using communication_io_exchange.
- *
- * @param port the port on which to listen for connections
- * @param host the interface to bind to
- */
-void communication_set_and_start_server(int port, const char *host);
-
-/**
- * @brief Sets the input file from which communication_io_exchange
- * will read the input.
- * Either this or communication_set_server must be called before
- * using communication_io_exchange.
- *
- * @param _input_file the input file that is used for I/O
- */
-void communication_set_input_file(FILE *_input_file);
-
-/**
- * @brief Sets the replica file to which communication_io_exchange will
- * write the input. Setting this is optional.
- *
- * @param _replica_file the file to which to replicate the inputs
- */
-void communication_set_replica_file(FILE *_replica_file);
-
-/**
- * @brief Perform an empty message write on the IO channel
- */
-void communication_reply();
-
-#endif
-// END of platform-dependent code
-
 #endif // __HAL_COMMUNICATION_H

firmware/src/hal/src/common/communication.c

@@ -0,0 +1,44 @@
+/**
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2021 RSK Labs Ltd
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#include "hal/communication.h"
+
+static unsigned char* msg_buffer;
+static size_t msg_buffer_size;
+
+// HAL implementation
+bool communication_init(unsigned char* _msg_buffer, size_t _msg_buffer_size) {
+    // Setup the exchange buffer
+    msg_buffer = _msg_buffer;
+    msg_buffer_size = _msg_buffer_size;
+    return true;
+}
+
+unsigned char* communication_get_msg_buffer() {
+    return msg_buffer;
+}
+
+size_t communication_get_msg_buffer_size() {
+    return msg_buffer_size;
+}

firmware/src/hal/src/ledger/communication.c

@@ -0,0 +1 @@
+../common/communication.c