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?