9 years, 1 month ago.

UIPServer stops responding

Hi, it's me again :)

In the beggining let me appologize for the wall of text and thank you for all your work in this library :)

I've been using UIPEthernet since you kindly helped me to run it on Nucleo F411RE and it was fun. But when I started to run stability tests on it I noticed something strange. When I start UIPServer it begins to do its job and then just stops. By "stops" I mean it doesn't indicate that there are valid requests waiting (and there are). As a starting point to my further research I used your

and added a simple DS1820 to read data from.

When first time I saw that I was afraid that something in my code breaks and that Nucleo hangs, so I have added a Ticker to blink LED1 and to my surprise - it was still blinking even when http reqests stop being processed. Then I added a simple printf:

                size = client.read(buf, size);
                string received((char*)buf);
                free(buf);
                // printf added here, commandCount starts at 0 
                // and is incremented after each reqest parsed after this point
                printf("%d", commandCount); 
                printf(" - %s", received.c_str());

And again - LED1 blinks, but after few requests (and that number is not constant, sometimes it runs for 60+ requests, sometimes goes silent after only 2; for now it looks quite random) console stops logging new requests and web clients can't connect to Nucleo (both web browser and my C# service that connects to Nucleo). After that point no new connections to Nucleo succeed and the only solution is to restart it (in fact as a failsafe I have added a Ticker that restarts it if there was no request registered after 100 seconds, but of course that is a temporary solution).

My next guess was that maybe the ENC28J60 does hang or stops parsing packets, but I've enabled printf's in UIPEthernet.cpp in void UIPEthernetClass::tick(void) and it in fact does receive them (and a lot of them to be honest, it logs both IP and ARP packets incoming).

And so I went and asked uncle google what he thinks and after many, many, maaaaaany hours I found this: https://github.com/ntruchsess/arduino_uip/issues/30 and boy I was glad - I wasn't the only one hitting my head :) It looks like Norbert Truchsess was able to fix this behaviour (https://github.com/ntruchsess/arduino_uip/commit/027171ee990ee8a54e40a102f56cdf17897e45a0) in his andruino library and I was even happier... But when I tried to modify your version of the library I have noticed two things: first of all your library was created after that fix was implemented and secondly - you have modified the code a lot and I couldn't figure out how to include his fix into your code and if it is necessary in the first place.

What I tried was to change #define's as he did in UIPClient.h and modify UIPClient.cpp to reflect that but I was aware that changing this won't fix the problem. Then I have changed UIPClient.cpp from:

if (data)

to:

if (data && data->state)

but that didn't help neither. Then I've tried to change UIPServer.cpp in UIPClient UIPServer::available(void) from:

if(UIPClient::_available(u))

to:

if(UIPClient::_available(u) && u->state & UIP_CLIENT_REMOTECLOSED)

and now I got some results... But "not perfect" is a mild understatement :) While requests are being logged (in that first place I have showed at the beggining), the clients don't receive any response :/ So I've reverted all my changes and as a temporary solution right after http_send I call client.stop(). That somehow helps, server stops after more requests but still stops nevertheless. I tried to make requests that have "Connection: Close" header (previously I tried with "Connection: Keep-Alive" - same result) but that didn't help neither.

While I'll try to work on that some more I was hoping you may be willing to look into that as well :)

On a side note - do you have by any chance mbed version of the HardwareSerial.h that can easily be used to debug this library? Out of hurry I ended up replacing Serial.print's with simple printf's, but that is a tedious work and before I start to write my own version of that helper I prefer to ask first, reinvent the wheel later :)

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Last updated: 23 Jul 2020

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Zoltan Hudak / UIPEthernet Featured

Mbed library for ENC28J60 Ethernet modules. Full support for TCP/IP and UDP Server, Client and HTTP server (webserver). DHCP and DNS is included. client, ENC28J60, ethernet, server, uIP, UIPEthernet