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Forum Index : Microcontroller and PC projects : Any TCP gurus out there?
| Author | Message | ||||
| matherp Guru  Joined: 11/12/2012 Location: United KingdomPosts: 9119 |
I've just posted this on the Pico forum but thought someone here may also be able to help When a browser connects to the Pico-W action as a TCP-Server on port 80 it requests a connection and once accepted sends a request as per the debug dump below. My code then satisfies that request and closes the PCB - all that works well. However, if preload is enabled on the browser - default on Chrome and Edge a second connection is requested which is accepted but no data is received by the Pico-W and the connection just stays open consuming resource - see the second code segment. I've implemented a timer to kill off runt connections and you can see my close acting in the code segment. However, despite getting a success return the polling continues until some seconds later I see the third code segment. Can anyone tell me what the TCP server should do when it sees the second connection but no request. Am I handling it correctly by pre-emptively closing it? Why is my close not stopping the connection immediately instead leaving LWIP to tidy up. If I don't close the second connection then my limited number of PCBs is exhausted and that will stop the program. Any help appreciated. Like DarkElvenAngel I'm seeing the program crashing after running for some time - often 12 hours or more and am trying to get to the bottom of the issue and these runt connections may not be the issue but are certainly untidy. TCP connection request 55910 -> 80. TCP connection established 55910 -> 80. HTTP Client connected 2003be80 on pcb 0 Connection still free 7 Tcp_HTTP_recv on pcb 0 / 441 tcp_recved: received 441 bytes, wnd 11680 (0). Stack pointer is 20041d58 free space on heap 10224 TCP connection request 55911 -> 80. TCP connection established 55911 -> 80. HTTP Client connected 2003bd38 on pcb 1 Connection still free 6 sending page header to pcb 0 sending page to pcb 0 sending page to pcb 0 sending page to pcb 0 sending page to pcb 0 sending page end to pcb 0 tcp_server_sent 2920 tcp_server_sent 2920 tcp_server_sent 958 tcp_close: closing in State: CLOSE_WAIT Close success 2003be80 on pcb 0 tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: polling application Warning PCB 1 still open tcp_close: closing in State: ESTABLISHED Close success 2003baa8 on pcb 1 tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: processing active pcb tcp_slowtmr: polling application tcp_slowtmr: processing active pcb tcp_slowtmr: removing pcb stuck in FIN-WAIT-2 tcp_pcb_purge |
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led-bloon Senior Member  Joined: 21/12/2014 Location: AustraliaPosts: 205 |
No guru but... You have access to the originating IP that makes the connection request. After a connection, reject (ignore) any further connection requests from the same IP until the original connection is closed? (I am sure the originating IP is constant) led Miss you George |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9119 |
Unfortunately, that doesn't work. It is perfectly reasonable for them to make multiple requests for pictures, css etc. The issue here is that it request the connection and then does nothing on it |
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LeoNicolas Guru Joined: 07/10/2020 Location: CanadaPosts: 479 |
Just for curiosity, have you test it with Firefox or any other browser that is not from the WebKit family? |
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homa Guru Joined: 05/11/2021 Location: GermanyPosts: 351 |
What kind of header does the second connection have? https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers |
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| matherp Guru Joined: 11/12/2012 Location: United KingdomPosts: 9119 |
It doesn't ever send anything, it just makes a connection request |
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TassyJim Guru Joined: 07/08/2011 Location: AustraliaPosts: 6098 |
Definitely not a guru of any kind. I doubt if closing the inactive connection will cause any problems with the browser. My "production" system is running 7.07.08RC5 and seems to be rock steady. My test system running 5.08.00b4 falls over without any connections being initiated via the network. It runs happily for a few hours or more before reboot and no heartbeat LED flashing although the USB console works. I am in the process of adding more debug code but I doubt if the extra TCPIP connection is causing the problems. Jim VK7JH MMedit MMBasic Help |
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TheMonkeys Regular Member  Joined: 15/12/2022 Location: AustraliaPosts: 59 |
I'm unsure if this will help, but I thought I'd share. I have observed that after a period of inactivity - around 3-5 minutes - the WebMite frequently takes approximately 7 seconds to respond to a browser request. This behaviour has been consistent for quite a while. This is regardless of the type of request (transmit page or file). I should add that I use javascript XMLHttpRequest() for many page requests, but it seems not to make a difference. Cheers, Chris. |
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| TheMonkeys Regular Member Joined: 15/12/2022 Location: AustraliaPosts: 59 |
Oh, yes. From my 404 log... 26-09-2023 01:29:07 2 GET / HTTP/1.1 Host: xxx.xxx.xxx.xxx:2040 User-Agent: Mozilla/5.0 (compatible; InternetMeasurement/1.0; +https://internet-measurement.com/) Connection: close Accept: */* Accept-Encoding: gzip 26-09-2023 02:00:02 0 Host: 192.168.0.102:2040 Connection: close This - as you can see from the dates - is a while ago. The second entry - a request from a PHP script on my logging server - is missing: GET /ldata.piml HTTP/1.1 from the start, which still happens every now & then. I've written a handler for it, but perhaps the WebMite is occasionally missing the first part of the request? Hope this helps, Chris. Edited 2023-12-16 16:33 by TheMonkeys |
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