From ea622e65c175bb08a816fd93d53a1be2b73b0377 Mon Sep 17 00:00:00 2001
From: Pig Monkey <pm@pig-monkey.com>
Date: Wed, 15 Jan 2025 18:01:39 -0800
Subject: [PATCH] toggle wifi on ethernet via networkmanager

Required only for the brave new post-TLP world.
---
 group_vars/all                                |  1 +
 .../files/wifi-wired-exclusive.sh             | 40 +++++++++++++++++++
 roles/networkmanager/tasks/main.yml           |  7 ++++
 3 files changed, 48 insertions(+)
 create mode 100755 roles/networkmanager/files/wifi-wired-exclusive.sh

diff --git a/group_vars/all b/group_vars/all
index cfe7d5e..9e40462 100644
--- a/group_vars/all
+++ b/group_vars/all
@@ -53,6 +53,7 @@ mail:
 
 network:
     conn_check: False
+    wifi_wired_exclusive: True
     trusted_uuid:
         - 39744b35-2f2f-4a18-9da4-7542a56c28c2
         - d2642f7e-9e58-4b00-82f8-26b4ef76a54e
diff --git a/roles/networkmanager/files/wifi-wired-exclusive.sh b/roles/networkmanager/files/wifi-wired-exclusive.sh
new file mode 100755
index 0000000..9d4cc8c
--- /dev/null
+++ b/roles/networkmanager/files/wifi-wired-exclusive.sh
@@ -0,0 +1,40 @@
+#!/usr/bin/env bash
+# Stolen from Ilija Matoski:
+# https://www.matoski.com/article/wifi-ethernet-autoswitch/
+
+name_tag="wifi-wired-exclusive"
+syslog_tag="$name_tag"
+skip_filename="/etc/NetworkManager/.$name_tag"
+
+if [ -f "$skip_filename" ]; then
+  exit 0
+fi
+
+interface="$1"
+action="$2"
+
+# Bail out if the action is not either up or down.
+if [[ "$action" != "up" && "$action" != "down" ]]; then
+    exit 0
+fi
+
+iface_type=$(nmcli dev | grep "^$interface" | tr -s ' ' | cut -d' ' -f2)
+iface_state=$(nmcli dev | grep "^$interface" | tr -s ' ' | cut -d' ' -f3)
+
+echo "$syslog_tag: Interface $interface = $iface_state ($iface_type) is $action"
+
+enable_wifi() {
+   echo "$syslog_tag: Interface $interface ($iface_type) is down, enabling wifi."
+   nmcli radio wifi on
+}
+
+disable_wifi() {
+   echo "$syslog_tag: Disabling wifi, ethernet connection detected."
+   nmcli radio wifi off
+}
+
+if [[ "$iface_type" = "ethernet" || -z "$iface_type" ]] && [ "$action" = "down" ]; then
+  enable_wifi
+elif [ "$iface_type" = "ethernet" ] && [ "$action" = "up"  ] && [ "$iface_state" = "connected" ]; then
+  disable_wifi
+fi
diff --git a/roles/networkmanager/tasks/main.yml b/roles/networkmanager/tasks/main.yml
index a90f75b..272fa7e 100644
--- a/roles/networkmanager/tasks/main.yml
+++ b/roles/networkmanager/tasks/main.yml
@@ -19,6 +19,13 @@
       src: random_mac.conf.j2
       dest: /etc/NetworkManager/conf.d/20-random_mac.conf
 
+- name: Push WiFi/Wired Exclusive dispatcher
+  copy:
+    src: wifi-wired-exclusive.sh
+    dest: /etc/NetworkManager/dispatcher.d/70-wifi-wired-exclusive
+    mode: 0755
+  when: network.wifi_wired_exclusive is defined and network.wifi_wired_exclusive == True
+
 - name: Enable and start NetworkManager
   service:
       name: NetworkManager.service