| 20 lines hidden |
| | | <glacius:metadata> |
| | | <title>WiFi Reconnection Script</title> |
| | | <description>Little script to automatically reconnect to wifi, e.g. on a Raspberry Pi</description> |
| | | <category>Code snippets</category> |
| | | <category>Programming</category> |
| | | <category>Bash</category> |
| | | </glacius:metadata> |
| | | |
| | | <p> |
| | | I recently upgraded my magic mirror from a 1st gen Raspberry Pi B to a Raspberry Pi 4. |
| | | The RPi4 has a builtin WiFi adapter so I don't need the dongle. I thought it would be |
| | | more stable, but so far not so much. It can't connect to my 2.4GHz SSID but kinda |
| | | connects to the 5GHz SSID. However, it periodically refuses to reconnect. And since |
| | | the Pi is locked inside a frame, duct-taped to the back of a monitor, it's not easy |
| | | to rip it off the wall to troubleshoot. |
| | | </p> |
| | | |
| | | <p> |
| | | Normally what I would so is just unplug and plug it back in to make it reconnect, but |
| | | that only seemed like a reasonable thing to do on a Pi from 2012, but not one from this |
| | | decade. So I wrote this cron script that kind of works. |
| | | </p> |
| | | |
| | | <p> |
| | | Basically it uses the network manager CLI utility to see if the WiFi is connected, |
| | | Basically it uses the |
| | | <a href="https://www.networkmanager.dev/docs/api/latest/nmcli.html">NetworkManager CLI utility</a> |
| | | to see if the WiFi is connected, |
| | | and if not, it cycles the radio off and then on. In the event that this doesn't work |
| | | for 15 minutes (900 seconds), it just reboots the whole machine. I'm tired of trying |
| | | to debug this nonsense so I'm taking a scorched Earth approach now. |
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| | | </p> |
| | | <glacius:code lang="bash"><![CDATA[ |
| | | #!/bin/bash |
| | | |
| | | tempFile=/tmp/wifi-reconnect |
| | | |
| | | if [[ ! -f "${tempFile}" ]]; then |
| | | touch "${tempFile}" |
| | | fi |
| | | |
| | | if ! nmcli connection show --active | grep wifi > /dev/null; then |
| | | lastConnected=$(cat "${tempFile}") |
| | | threshold=900 |
| | | if [[ -n "${lastConnected}" && $(( lastConnected + threshold )) -lt $(date +%s) ]]; then |
| | | echo "$(date) not connected, haven't connected for ${threshold}s (last: ${lastConnected}), rebooting..." |
| | | shutdown -r now |
| | | exit |
| | | fi |
| | | |
| | | echo "$(date) not connected, cycling wifi radio..." |
| | | nmcli radio wifi off |
| | | nmcli radio wifi on |
| | | else |
| | | echo "$(date) connected" |
| | | date +%s > "${tempFile}" |
| | | fi |
| | | ]]></glacius:code> |
| | | |
| | | <p> |
| | | This runs every minute from a cron job in <code>/etc/cron.d/wifi-reconnect</code>: |
| | | </p> |
| | | |
| | | <glacius:code lang="cron"><![CDATA[* * * * * root /path/to/script/wifi-reconnect.sh >> /var/log/wifi-reconnect.log 2>&1 |
| | | ]]></glacius:code> |
| | | |
| | | <p> |
| | | The log file looks like this: |
| | | </p> |
| | | |
| | | <glacius:code lang="plaintext"><![CDATA[Sat 23 Mar 13:12:01 PDT 2024 connected |
| | | Sat 23 Mar 13:13:01 PDT 2024 not connected, cycling wifi radio... |
| | | Sat 23 Mar 13:14:01 PDT 2024 connected |
| | | Sat 23 Mar 13:15:02 PDT 2024 connected |
| | | Sat 23 Mar 13:16:01 PDT 2024 connected |
| | | Sat 23 Mar 13:17:01 PDT 2024 connected |
| | | Sat 23 Mar 13:18:01 PDT 2024 connected |
| | | Sat 23 Mar 13:19:01 PDT 2024 connected |
| | | Sat 23 Mar 13:20:01 PDT 2024 connected |
| | | Sat 23 Mar 13:21:01 PDT 2024 connected |
| | | Sat 23 Mar 13:22:01 PDT 2024 connected |
| | | Sat 23 Mar 13:23:02 PDT 2024 connected |
| | | ]]></glacius:code> |
| | | |