"Server did not honor partial content request"

[Jared]

Hey DZ,

I'm having some trouble with the download_client. It's not playing nice with the HTTP server I'm using. On the last chunk of data, the nRF91 is issuing a Content-Range that doesn't always play nice with all server implementations. The server I'm using is returning a 416 error. 

Here's the progress from the embedded side:

2021-03-09T02:02:42.279Z DEBUG modem << [00:01:00.078,948] [0m<inf> download_client: Downloaded 194560/200595 bytes (96%)[0m
2021-03-09T02:02:42.760Z DEBUG modem << [00:01:00.558,929] [0m<inf> download_client: Downloaded 196608/200595 bytes (98%)[0m
2021-03-09T02:02:43.135Z DEBUG modem << [00:01:00.934,387] [0m<inf> download_client: Downloaded 198656/200595 bytes (99%)[0m
2021-03-09T02:02:43.529Z DEBUG modem << [00:01:01.325,347] [1;31m<err> download_client: Server did not honor partial content request[0m
2021-03-09T02:02:43.558Z DEBUG modem << [00:01:01.335,388] [1;31m<err> fota_download: Download client error[0m
2021-03-09T02:02:43.559Z DEBUG modem << [00:01:01.341,766] [0m<inf> dfu_target_mcuboot: MCUBoot image upgrade aborted.[0m

Here's the log from the HTTP server.

{"level":"info","ts":1615255361.8753276,"logger":"http.log.access","msg":"handled request","request":{"remote_addr":"52.12.23.139:64562","proto":"HTTP/1.1","method":"GET","host":"pyrinas-dev-ota.jaredwolff.com","uri":"/images/352656102712240.bin","headers":{"Range":["bytes=196608-198655"],"Connection":["keep-alive"]},"tls":{"resumed":false,"version":771,"cipher_suite":49162,"proto":"","proto_mutual":true,"server_name":"pyrinas-dev-ota.jaredwolff.com"}},"common_log":"52.12.23.139 - - [09/Mar/2021:02:02:41 +0000] \"GET /images/352656102712240.bin HTTP/1.1\" 206 2048","duration":0.00488638,"size":2048,"status":206,"resp_headers":{"Accept-Ranges":["bytes"],"Last-Modified":["Tue, 09 Mar 2021 01:50:16 GMT"],"Server":["Caddy"],"Date":["Tue, 09 Mar 2021 02:02:40 GMT"],"Content-Range":["bytes 196608-198655/200595"],"Content-Length":["2048"],"Content-Type":["application/octet-stream"]}}
{"level":"error","ts":1615255362.3557446,"logger":"http.log.access","msg":"handled request","request":{"remote_addr":"52.12.23.139:64562","proto":"HTTP/1.1","method":"GET","host":"pyrinas-dev-ota.jaredwolff.com","uri":"/images/352656102712240.bin","headers":{"Range":["bytes=198656-200595"],"Connection":["keep-alive"]},"tls":{"resumed":false,"version":771,"cipher_suite":49162,"proto":"","proto_mutual":true,"server_name":"pyrinas-dev-ota.jaredwolff.com"}},"common_log":"52.12.23.139 - - [09/Mar/2021:02:02:42 +0000] \"GET /images/352656102712240.bin HTTP/1.1\" 416 0","duration":0.00314682,"size":0,"status":416,"resp_headers":{"Content-Length":["0"],"Date":["Tue, 09 Mar 2021 02:02:42 GMT"],"Server":["Caddy"],"Content-Range":["bytes */200595"]}}

Are there any workarounds for this? I'm downloading a FOTA update so there's a need for the payload size to be fixed. (Currently set to 2048)

Thank you!

Jared

[Håkon Alseth]

Hi,

 

Does your server support partial content requests? Do you know which httpd and version is running? 

Are you able to do a tcpdump on the server side, or provide a modem trace of the FOTA transaction?

 

Here's a .pcap of the http_update/application_update which I took just to see how the nRF sends its http requests:

trace-2021-03-09T12-49-16.pcap

 

Kind regards,

Håkon

[Jared]

Håkon Alseth said:

Does your server support partial content requests? Do you know which httpd and version is running? 

I'm using Caddy (caddy-2.2.0 on FreeBSD) as a reverse proxy to the plaintext server. It does support partial content requests. The nRF9160 was able to download up until the last chunk of data. The one that is causing the 416 error is Caddy on the HTTPS side. The proxied server never sees the last request when Content-Range header was set to:

"Content-Range":["bytes */200595"]

Håkon Alseth said:

Here's a .pcap of the http_update/application_update which I took just to see how the nRF sends its http requests:

The http requests are handled by the MFW correct?

I'll get a modem trace to you later today. Thanks for the support!