Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Håkon Alseth — Mon, 10 Jun 2024 07:14:01 GMT

Hi,

[quote user="Voxorin"]I didn't get the download client working due to other errors, 118 & 116 I think it was. [/quote]

That is ETIMEDOUT / EHOSTUNREACH:

https://github.com/zephyrproject-rtos/zephyr//blob/main/lib/libc/minimal/include/errno.h#L101-L103

Indicating that there's a network related issue.

[quote user="Voxorin"]

I don't have too much time to work on that though. For now I got things working by fragmenting and retrying until the download is complete.

I have to close the socket and create a new one to stop the issue from happening again immediately. Is there a way to manually clear the offloaded socket receive buffers?

[/quote]

Can you share a modem trace of the issue?

Clearing the buffers can be done by either reading out via recv() or closing the socket and re-opening it again.

Kind regards,

Håkon

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Voxorin — Sun, 09 Jun 2024 16:13:11 GMT

I didn't get the download client working due to other errors, 118 & 116 I think it was. I don't have too much time to work on that though. For now I got things working by fragmenting and retrying until the download is complete.

I have to close the socket and create a new one to stop the issue from happening again immediately. Is there a way to manually clear the offloaded socket receive buffers?

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Håkon Alseth — Wed, 05 Jun 2024 08:38:20 GMT

Hi,

Could you test with download_client to verify that you're able to get that working? If download_client works; you'll need to effectively re-implement the http parsing in your own application. You can look into the sources for how the download client performs such operations.

Kind regards,

Håkon

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Voxorin — Tue, 04 Jun 2024 15:36:27 GMT

How can I resolve this without the download client? I'd like to avoid limiting portability and rewriting too much code.

I've reduced the chunks size to 2000KB< and it still gets about 1/3 of the way through the download before giving the EMSGSIZE error. I'm struggling to find the actual cause of the issue.

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Håkon Alseth — Tue, 04 Jun 2024 12:23:02 GMT

Hi,

You can disable the range request by setting CONFIG_DOWNLOAD_CLIENT_RANGE_REQUESTS=n.

Note that this does not allow you to resume a download in case it was interrupted before finishing.

Kind regards,

Håkon

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Voxorin — Mon, 03 Jun 2024 22:23:23 GMT

There has to be a workaround that doesn't require 74 GET requests, right? It repeatedly downloads at least 49KB every time

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Voxorin — Mon, 03 Jun 2024 17:48:16 GMT

Hi Håkon,

Thanks for pointing me in the right direction. I see the download client uses Content-Range requests to get around the memory constraint.

I'd like to avoid multiple HTTP requests if possible. Can the issue be avoided if the chunk size is set to 1280 and the receive buffer is processed immediately?

RE: Modem error 122 (EMSGSIZE) when downloading file over ~50KB via HTTP/TCP/IPv6/LTE-M

Håkon Alseth — Mon, 03 Jun 2024 07:20:59 GMT

Hi,

Based on the port, it looks like you are using a secure connection.

Secure sockets has a restriction of max. 2k recv limit. Try to reduce the fragment size by setting CONFIG_DOWNLOAD_CLIENT_HTTP_FRAG_SIZE_1024=y for instance.

Kind regards,

Håkon