[lwip-users] Connection freeze after 29200 Bytes

[Norbert Kleber]

Hello everyone,

I ran into a problem while implementing the LwIP stack v1.3.2 onto the STM32F4 Evalboard.
My Intention is to build a bootloader application while using Raw API. I want to transmit the .bin file in Parts of 64kB (matching the CCM) to the microcontroller, put it into the CCM and after that is filled or all data is transmitted to write the data into the FLASH. As long the file to transfer is smaller than this magical 29200 Bytes every thing works fine, but if it exceeds that limit the TCP connection freezes after transmitting the 29200Bytes. Wireshark didn't see any messages following that freeze not even a keep alive message. If i stop my terminal program that is sending the data the frame for closing the connection is send and answered. To control the data transmission i have a second tcp connection to another port where i am sending control instructions like how many bytes to expect. The acknowledgements to these frames had somehow a decreasing window size.
That happens as follows:

1. frame window is 2920
2. receive frame length 13
3. ack frame window 2907

 Is there a mistake in interfacing the lwIP stack? The windowsize update function is disabled.

I took the driver as well as the interface out of the ethernet example for STM32F4Evalboar + STM32F4DIS-BB from element 14.

i would be grateful for any hint.

sincerly,

Norbert