luci-mod-status: move getConntrackList from ubus to fs.exec

[jjm2473]

to prevent procd from being kicked off by ubusd
due to large amounts of data.
See openwrt/openwrt#9747

Fixes #6360

• This PR is not from my main or master branch 💩, but a separate branch ✅
• Each commit has a valid ✒️ Signed-off-by: <my@email.address> row (via git commit --signoff)
• Each commit and PR title has a valid 📝 <package name>: title first line subject for packages
• Incremented 🆙 any PKG_VERSION in the Makefile
• Tested on: ✅ qemu arm64, 25.12.1, Chrome
• ( Preferred ) Mention: @jow- @systemcrash
• ( Optional ) Closes: luci: Missleading error message when rpcd fails #6360
• Description:
  Move getConntrackList from ubus to web to prevent procd from being kicked off by ubusd due to large amounts of data.

Has been tested with a fake 5MB /proc/net/nf_conntrack, procd not kicked off (Such a large amount of data can actually cause browser lag.).

[jjm2473]

This is test on 24.10.5.
Create thousands of connections using https://qps.itzmx.com/.

[jjm2473]

[v2]:

1. Use grep to filter out connections in the TIME_WAIT state on backend to reduce front-end load
2. Ignore unused fields
3. Reduce commit message

Link to v1: jjm2473@bc970ea

[jjm2473]

Tested with over 10,000 connections, no issues were found, and the frontend remained stable.

[jow-]

That's a good idea, I like it. I just wonder if it would be better to have a dedicated backend route which takes care of the parsing and spits out a JSON for the front end to consume instead of parsing the raw system files in the frontend code directly.

[ptpt52]

LGTM

[jjm2473]

In fact, modern browsers generally outperform routers, so it might be more appropriate to perform the main computation in the browser?
The backend could use grep or sed to filter out some data to reduce network traffic, since luci (uhttpd) currently doesn't compress data.

[jjm2473]

Update: use grep -vF instead of grep -v, saving ~60% CPU time on backend.

[jjm2473]

[v3]:

1. Add a wrapper for easy align to the /usr/sbin/conntrack -L -o extended fallback in sys.uc (the fallback was added by a30c8d8 ).

Link to v2: jjm2473@f80986d
Link to v1: jjm2473@bc970ea