4 files changed, 19 insertions, 10 deletions

diff --git a/src/isotp/isotp.c b/src/isotp/isotp.c
index f5b20795..58243123 100644
--- a/src/isotp/isotp.c
+++ b/src/isotp/isotp.c
@@ -33,23 +33,26 @@ void isotp_message_to_string(const IsoTpMessage* message, char* destination,
             message->arbitration_id, message->payload);
 }
 
-void isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
+bool isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
         const uint16_t arbitration_id, const uint8_t data[],
         const uint8_t data_length) {
+    bool message_completed = false;
+
     if(data_length < 1) {
-        return;
+        return message_completed;
     }
 
     if(handle->type == ISOTP_HANDLE_RECEIVING) {
         if(handle->receive_handle.arbitration_id != arbitration_id) {
-            return;
+            return message_completed;
         }
     } else if(handle->type == ISOTP_HANDLE_SENDING) {
         if(handle->send_handle.receiving_arbitration_id != arbitration_id) {
-            return;
+            return message_completed;
         }
     } else {
         shims->log("The ISO-TP handle is corrupt");
+        return message_completed;
     }
 
     IsoTpProtocolControlInformation pci = (IsoTpProtocolControlInformation)
@@ -73,11 +76,12 @@ void isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
                 size: payload_length
             };
 
-            isotp_handle_single_frame(handle, &message);
+            message_completed = isotp_handle_single_frame(handle, &message);
             break;
          }
         default:
             shims->log("Only single frame messages are supported");
             break;
     }
+    return message_completed;
 }
diff --git a/src/isotp/isotp.h b/src/isotp/isotp.h
index e3ec588a..4f58dac4 100644
--- a/src/isotp/isotp.h
+++ b/src/isotp/isotp.h
@@ -93,7 +93,13 @@ IsoTpShims isotp_init_shims(LogShim log,
         SendCanMessageShim send_can_message,
         SetTimerShim set_timer);
 
-void isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
+/* Public:
+ *
+ * Returns true if a complete ISO-TP message was sent or received as of
+ * processing this CAN frame. Check the 'success' and 'completed' flag on the
+ * handle to make sure.
+ */
+bool isotp_receive_can_frame(IsoTpShims* shims, IsoTpHandle* handle,
         const uint16_t arbitration_id, const uint8_t data[],
         const uint8_t size);
 
diff --git a/src/isotp/receive.c b/src/isotp/receive.c
index 1d623384..e69c59b7 100644
--- a/src/isotp/receive.c
+++ b/src/isotp/receive.c
@@ -1,8 +1,8 @@
 #include <isotp/receive.h>
 
-void isotp_handle_single_frame(IsoTpHandle* handle,
-        IsoTpMessage* message) {
+bool isotp_handle_single_frame(IsoTpHandle* handle, IsoTpMessage* message) {
     isotp_complete_receive(handle, message);
+    return true;
 }
 
 void isotp_complete_receive(IsoTpHandle* handle, IsoTpMessage* message) {
diff --git a/src/isotp/receive.h b/src/isotp/receive.h
index b7c17963..b01e12de 100644
--- a/src/isotp/receive.h
+++ b/src/isotp/receive.h
@@ -11,8 +11,7 @@ extern "C" {
 
 void isotp_complete_receive(IsoTpHandle* handle, IsoTpMessage* message);
 
-void isotp_handle_single_frame(IsoTpHandle* handle,
-        IsoTpMessage* message);
+bool isotp_handle_single_frame(IsoTpHandle* handle, IsoTpMessage* message);
 
 #ifdef __cplusplus
 }