# ModemManager Hotplug script: Request for review **URL:** \ **Category:** Community Builds, Projects & Packages\ **Created:** [August 7, 2019, 10:44pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306 "2019-08-07T22:44:59Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![biangbiangmian](https://forum.openwrt.org/user_avatar/forum.openwrt.org/biangbiangmian/32/2379_2.png) [@biangbiangmian](https://forum.openwrt.org/u/biangbiangmian)\ **Post date:** [August 7, 2019, 10:45pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/1 "2019-08-07T22:45:00Z")
> This hotplug script is intended to work with ModemManager connections to keep the modem connection up and running. Sometimes ModemManager will think the modem is connected even though the data session is inactive. I don't have a full understanding, but I surmise it is basically because the object referencing the previous state of the modem (bearers, modem, etc) has gone stale. The way I'm working around this is to just restart the ModemManager service and bring the iface back up. One problem at the moment is if you disable/stop the modem interface it will be restarted by the hotplug script. Is there a hotplug event that could be used to not fire the script in that case? Or Perhaps just reference a UCI configuration element? Currently it only works with ModemManager 1.8, but work on updating it to 1.10 should start soon. ---
**Author:** ![biangbiangmian](https://forum.openwrt.org/user_avatar/forum.openwrt.org/biangbiangmian/32/2379_2.png) [@biangbiangmian](https://forum.openwrt.org/u/biangbiangmian)\ **Post date:** [August 10, 2019, 11:08pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/2 "2019-08-10T23:08:53Z")
Refactored ---
**Author:** ![vgaetera](https://forum.openwrt.org/user_avatar/forum.openwrt.org/vgaetera/32/113586_2.png) [@vgaetera](https://forum.openwrt.org/u/vgaetera)\ **Post date:** [August 11, 2019, 12:03am UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/3 "2019-08-11T00:03:25Z")
> **[ShellCheck – shell script analysis tool](https://www.shellcheck.net/)** > > ShellCheck finds bugs in your shell scripts ---
**Author:** ![vgaetera](https://forum.openwrt.org/user_avatar/forum.openwrt.org/vgaetera/32/113586_2.png) [@vgaetera](https://forum.openwrt.org/u/vgaetera)\ **Post date:** [August 12, 2019, 9:46am UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/4 "2019-08-12T09:46:23Z")
1. Useless use of `cat`: ``` cat FILE | grep PATTERN grep PATTERN FILE ``` 1. Deadline for `ping` is mandatory: ```bash ping ... ping -w 30 ... ``` 1. Extract large command blocks: ```bash if EXPR; then LARGE_BLOCK_OF_COMMANDS fi EOF if ! EXPR; then exit fi LARGE_BLOCK_OF_COMMANDS EOF ``` ---
**Author:** ![biangbiangmian](https://forum.openwrt.org/user_avatar/forum.openwrt.org/biangbiangmian/32/2379_2.png) [@biangbiangmian](https://forum.openwrt.org/u/biangbiangmian)\ **Post date:** [August 12, 2019, 8:08pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/5 "2019-08-12T20:08:00Z")
Thank you for the suggestions. It makes sense 1. Use grep only, so it just uses one command 2. So we put a maximum running time on that command 3. To exit early to save some CPU cycles ---
**Author:** ![trendy](https://forum.openwrt.org/user_avatar/forum.openwrt.org/trendy/32/8800_2.png) [@trendy](https://forum.openwrt.org/u/trendy)\ **Post date:** [March 18, 2022, 4:02pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/6 "2022-03-18T16:02:06Z")
Is there currently any way to restart an interface that went down? I have a Rasbperry Pi 4 with 4 huawei e3372h-320. They work fine most of the time, but at certain points they get disconnected and I have to either manually restart them from Luci or ifup from cli. I tried also to do the same from mwan3.user with ```nohighlight if ["${ACTION}" = "disconnected"] && ["${INTERFACE}" = "tmobile"] ; then curl -X POST --silent --data-urlencode \ "payload={\"text\": \"<@UA9128UNL> <@U671KBC4W4S> whale tmobile down\"}" \ https://hooks.slack.com/services/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 ifdown tmobile ; sleep 5; ifup tmobile fi ``` I get the slack notification, but the interface remains down. I'd prefer to restart only the interface and not the whole modemmanager, as the rest of the interfaces are working. ---
**Author:** ![biangbiangmian](https://forum.openwrt.org/user_avatar/forum.openwrt.org/biangbiangmian/32/2379_2.png) [@biangbiangmian](https://forum.openwrt.org/u/biangbiangmian)\ **Post date:** [March 19, 2022, 8:22am UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/7 "2022-03-19T08:22:53Z")
You might want to look into issuing a reboot command to that particular modem before doing an ifup of that modem's OpenWrt interface. If you don't care about preserving the Modem object state, a straightforward way to achieve this via ModemManager is by sending your modem's reboot AT command to that modem via `--command`. ---
**Author:** ![trendy](https://forum.openwrt.org/user_avatar/forum.openwrt.org/trendy/32/8800_2.png) [@trendy](https://forum.openwrt.org/u/trendy)\ **Post date:** [April 14, 2022, 9:28pm UTC](https://forum.openwrt.org/t/modemmanager-hotplug-script-request-for-review/42306/8 "2022-04-14T21:28:44Z")
Most of the times it seems that a modem reconnection is enough before issuing the `ifup`. To automate it I came up with the following script. It waits until the modem reaches a `registered` state, when connection is possible. Not very elegant, but open to suggestions. ```nohighlight #!/bin/sh for i in $(/usr/bin/mmcli -L | cut -d '/' -f 6 | cut -b 1) do echo Setting state for modem $i. state=$(/usr/bin/mmcli -m $i | grep "| state:" | cut -d ':' -f 2 | cut -d ' ' -f 2 | sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,2})?)?[mGK]//g") #echo "state set" echo Modem $i is in $state state. while [$state != "connected"] do echo "entered while" if [$state == "registered"] then echo "registered state, connecting..." /usr/bin/mmcli -m $i --simple-connect="apn=internet,ip-type=ipv4,allow-roaming=yes" sleep 15 echo "setting new state" state=$(/usr/bin/mmcli -m $i | grep "| state:" | cut -d ':' -f 2 | cut -d ' ' -f 2 | sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,2})?)?[mGK]//g") echo New state is $state else echo Not Registered. sleep 5 state=$(/usr/bin/mmcli -m $i | grep "| state:" | cut -d ':' -f 2 | cut -d ' ' -f 2 | sed -r "s/\x1B\[([0-9]{1,3}(;[0-9]{1,2})?)?[mGK]//g") fi done done echo All connected, bye... ``` edit: fixed the formatting of the **connected** which didn't work with the comparison in while.