From e357c6a1dc2b1eaa5ec4b6b1633ae8d1de874781 Mon Sep 17 00:00:00 2001
From: DJ2LS <dj2ls@proton.me>
Date: Wed, 13 Dec 2023 23:07:06 +0100
Subject: [PATCH] WIP ARQ - final crc check

---
 modem/arq_session_irs.py | 13 +++++++++++--
 modem/helpers.py         | 11 +++++++----
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/modem/arq_session_irs.py b/modem/arq_session_irs.py
index 22da422d..c9fbf1e6 100644
--- a/modem/arq_session_irs.py
+++ b/modem/arq_session_irs.py
@@ -2,6 +2,7 @@ import threading
 import data_frame_factory
 import queue
 import arq_session
+import helpers
 
 class ARQSessionIRS(arq_session.ARQSession):
 
@@ -52,6 +53,9 @@ class ARQSessionIRS(arq_session.ARQSession):
     def _all_data_received(self):
         return self.received_bytes == len(self.received_data)
 
+    def _final_crc_check(self):
+        return self.received_crc == helpers.get_crc_32(bytes(self.received_data)).hex()
+
     def handshake_session(self):
         if self.state in [self.STATE_CONN_REQ_RECEIVED, self.STATE_WAITING_INFO]:
             self.send_open_ack()
@@ -86,8 +90,13 @@ class ARQSessionIRS(arq_session.ARQSession):
             retries -= 1
 
         if self._all_data_received():
-            self.set_state(self.STATE_ENDED)
-        else: 
+            if self._final_crc_check():
+                self.set_state(self.STATE_ENDED)
+            else:
+                self.logger.warning("CRC check failed.")
+                self.set_state(self.STATE_FAILED)
+
+        else:
             self.set_state(self.STATE_FAILED)
 
 
diff --git a/modem/helpers.py b/modem/helpers.py
index 57f28ee6..85af20d7 100644
--- a/modem/helpers.py
+++ b/modem/helpers.py
@@ -49,6 +49,9 @@ def get_crc_8(data: str) -> bytes:
     Returns:
         CRC-8 (CCITT) of the provided data as bytes
     """
+    if not isinstance(data, (bytes)) or isinstance(data, (bytearray)):
+        data = bytes(data,"utf-8")
+
     crc_algorithm = crcengine.new("crc8-ccitt")  # load crc8 library
     crc_data = crc_algorithm(data)
     crc_data = crc_data.to_bytes(1, byteorder="big")
@@ -68,7 +71,7 @@ def get_crc_16(data: str) -> bytes:
     Returns:
         CRC-16 (CCITT) of the provided data as bytes
     """
-    if not isinstance(data, (bytes)):
+    if not isinstance(data, (bytes)) or isinstance(data, (bytearray)):
         data = bytes(data,"utf-8")
     
     crc_algorithm = crcengine.new("crc16-ccitt-false")  # load crc16 library
@@ -88,7 +91,7 @@ def get_crc_24(data: str) -> bytes:
     Returns:
         CRC-24 (OpenPGP) of the provided data as bytes
     """
-    if not isinstance(data, (bytes)):
+    if not isinstance(data, (bytes)) or isinstance(data, (bytearray)):
         data = bytes(data,'utf-8')
     crc_algorithm = crcengine.create(
         0x864CFB,
@@ -115,8 +118,8 @@ def get_crc_32(data: str) -> bytes:
     Returns:
         CRC-32 of the provided data as bytes
     """
-    if not isinstance(data, (bytes)):
-        data = bytes(data,"utf-8")
+    if not isinstance(data, (bytes)) or isinstance(data, (bytearray)):
+        data = bytes(data, "utf-8")
     crc_algorithm = crcengine.new("crc32")  # load crc32 library
     return crc_algorithm(data).to_bytes(4, byteorder="big")