question on pygpsclient termination of NTRIP client connection

[pat-2010]

Troubleshooting a different problem I saw the following behavior. Is it expected?

Configuration: Raspberry Pi 5 running pypgsclient 1.4.22. Python 3.11.42. GPS receiver not applicable, since I see this behavior without turning on my GPS receiver. EDIT: noticed that my pygpsclient version was out of date. Updated to 1.4.24 and repeated the test with no change.

When I stop the NTRIP client using the stop button on the bottom of the NTRIP client connection, the status at the bottom says "Disconnected". Using Wireshark I can see the NTRIP message from the server and the ACK from my computer. When I disconnect, my computer continues to send ACKs and the server thinks I'm still connected. It's not until I exit pygpsclient that I get a different message from my computer that actually disconnects from the NTRIP server.

I have the wireshark stream saved in case any info there would be useful. Poking around the message stream, the last 3 messages are:

1- a 383 byte message from the server (normal transmission)
2- an ack from my computer
3- another ack from my computer, this time with the Reset bit set.

Wireshark packet dissection for the last 3 messages. Edited for brevity. Note that 132.239.152.175 is the NTRIP server.

No. Time Source Destination Protocol Length Info
275 10:58:00.262518025 132.239.152.175 192.168.1.80 TCP 383 ICY 200 OK [TCP segment of a reassembled PDU]
Frame 275: 383 bytes on wire (3064 bits), 383 bytes captured (3064 bits) on interface any, id 0
...
Flags: 0x018 (PSH, ACK)
000. .... .... = Reserved: Not set
...0 .... .... = Accurate ECN: Not set
.... 0... .... = Congestion Window Reduced: Not set
.... .0.. .... = ECN-Echo: Not set
.... ..0. .... = Urgent: Not set
.... ...1 .... = Acknowledgment: Set
.... .... 1... = Push: Set
.... .... .0.. = Reset: Not set
.... .... ..0. = Syn: Not set
.... .... ...0 = Fin: Not set
[TCP Flags: ·······AP···]
...

No. Time Source Destination Protocol Length Info
276 10:58:00.262570378 192.168.1.80 132.239.152.175 TCP 68 55374 → 2104 [ACK] Seq=211 Ack=14426 Win=64128 Len=0
Frame 276: 68 bytes on wire (544 bits), 68 bytes captured (544 bits) on interface any, id 0
...
1000 .... = Header Length: 32 bytes (8)
Flags: 0x010 (ACK)
000. .... .... = Reserved: Not set
...0 .... .... = Accurate ECN: Not set
.... 0... .... = Congestion Window Reduced: Not set
.... .0.. .... = ECN-Echo: Not set
.... ..0. .... = Urgent: Not set
.... ...1 .... = Acknowledgment: Set
.... .... 0... = Push: Not set
.... .... .0.. = Reset: Not set
.... .... ..0. = Syn: Not set
.... .... ...0 = Fin: Not set
[TCP Flags: ·······A····]
...

No. Time Source Destination Protocol Length Info
277 10:58:00.373324068 192.168.1.80 132.239.152.175 TCP 68 55374 → 2104 [RST, ACK] Seq=211 Ack=14426 Win=64128
Frame 277: 68 bytes on wire (544 bits), 68 bytes captured (544 bits) on interface any, id 0
...
1000 .... = Header Length: 32 bytes (8)
Flags: 0x014 (RST, ACK)
000. .... .... = Reserved: Not set
...0 .... .... = Accurate ECN: Not set
.... 0... .... = Congestion Window Reduced: Not set
.... .0.. .... = ECN-Echo: Not set
.... ..0. .... = Urgent: Not set
.... ...1 .... = Acknowledgment: Set
.... .... 0... = Push: Not set
.... .... .1.. = Reset: Set
.... .... ..0. = Syn: Not set
.... .... ...0 = Fin: Not set
[TCP Flags: ·······A·R··]
...

[semuadmin]

Install this branch of pygnssutils and try again - let me know how you get on...

 python3 -m pip install git+https://github.com/semuconsulting/[email protected]

[pat-2010]

That works. Thanks.

[semuadmin]

Thanks for confirming - fix to #98 will go into v1.1.5.

And thanks for the generous donation - very much appreciated 😃.