[lwip-users] TCP Dup ACKs and TCP Window full

[Adrian Figueroa]

Hello,

 

I am writing a bootloader application that receives data over ethernet for flashing the processor it runs on. This is implemented on an STM32F746 running the ChibiOS-RTOS and the HAL drivers that come with it. Consequently, the netconn-api is used. I run Lwip 1.4.1, because Lwip 2.X was not yet ported to ChibiOS and I cannot to do it myself.

 

Lwip is used to implement a simple TCP server. A python TCP client connects to it and sends a chunk of data (around 200k).

 

I moved Lwip pools and heap to external SDRAM, so I can store large amounts of packets without discarding them.

 

First, the TCP server thread waits for an incoming connection with “netconn_accept()”. Find this in “server.c”, attached to this mail. There is also a “helper” thread that cleans things up after a connection was closed (dynamic threads).

 

After “netconn_accept()”, the netconn is handed over to a thread that receives data. Find the receiver functionality in “receiver.c”.

 

The receiver constantly calls netconn_recv(), until the connection is closed. A netbuf is filled each time and chained to the previous netbuf. I also have an evaluation thread that works on the received netbufs, but it does not do anything at the moment. In the end, I have a long netbuf chain in memory, ready for evaluation.

 

The problem is that I lose some of the packets in the process. Find the dump from Wireshark attached. My lwipopts.h is also included in the mail. I chose very generous amounts of storage for all pools, because I have 32 MB of SDRAM available. I get no errors at all in lwip_stats.

 

Do you have any suggestions?

 

Thank you in advance,

Adrian

 

 

 

 

server.c
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receiver.c
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dump_long.pcapng
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lwipopts.h
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