From da6dd5a2273609dc9b275c1a0c1cc402b624101f Mon Sep 17 00:00:00 2001
From: Pavel Kirienko <pavel.kirienko@gmail.com>
Date: Fri, 3 Jul 2015 06:16:50 +0300
Subject: [PATCH] TransferReceiver: Checking for unexpected start of transfer

---
 libuavcan/src/transport/uc_transfer_receiver.cpp | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/libuavcan/src/transport/uc_transfer_receiver.cpp b/libuavcan/src/transport/uc_transfer_receiver.cpp
index 0ce3999466..9fc9e9b4e0 100644
--- a/libuavcan/src/transport/uc_transfer_receiver.cpp
+++ b/libuavcan/src/transport/uc_transfer_receiver.cpp
@@ -75,6 +75,11 @@ bool TransferReceiver::validate(const RxFrame& frame) const
         registerError();
         return false;
     }
+    if (frame.isStartOfTransfer() && (buffer_write_pos_ != 0))
+    {
+        UAVCAN_TRACE("TransferReceiver", "Unexpected start of transfer, %s", frame.toString().c_str());
+        registerError();
+    }
     if (frame.getToggle() != next_toggle_)
     {
         UAVCAN_TRACE("TransferReceiver", "Unexpected toggle bit (not %i), %s",