Fixed up QMI data session bring up/maintenance

Makefile

-all: network-config qmi-service qmi-monitor-timer qmi-monitor-service
+all: network-config udev-config qmi-service qmi-monitor-timer qmi-monitor-service
 	tar xf libqmi-1.38.0.tar.gz
 	mkdir libqmi-1.38.0/build
 	cd libqmi-1.38.0/build && meson --prefix=/usr --buildtype=release -D bash_completion=false -D qrtr=false -D man=false -Dudev=false -Dmbim_qmux=false -Dintrospection=false ..
@@ -6,10 +6,10 @@ all: network-config qmi-service qmi-monitor-timer qmi-monitor-service
 	cd libqmi-1.38.0/build && ninja test
 	cd libqmi-1.38.0/build && ninja install
 	@echo "$$NETWORK_CONFIG" > /etc/systemd/network/wwan0.network
+	@echo "$$UDEV_CONFIG" > /etc/udev/rules.d/99-qmi.rules
 	install -m 0755 qmi-stats /usr/sbin
 	install -m 0755 qmi-monitor /usr/sbin
 	@echo "$$QMI_SERVICE" > /lib/systemd/system/qmi.service
-	systemctl enable qmi.service
 	@echo "$$QMI_MONITOR_TIMER" > /lib/systemd/system/qmi-monitor.timer
 	@echo "$$QMI_MONITOR_SERVICE" > /lib/systemd/system/qmi-monitor.service
 	systemctl enable qmi-monitor.timer
@@ -24,33 +24,41 @@ Name=wwan0
 
 [Network]
 DHCP=ipv4
+ConfigureWithoutCarrier=yes
+LinkLocalAddressing=no
+IPv6AcceptRA=no
+LLDP=no
+EmitLLDP=no
 
 [DHCP]
 RouteMetric=2048
 endef
 export NETWORK_CONFIG
 
+udev-config:
+define UDEV_CONFIG
+ACTION=="add", SUBSYSTEM=="net", KERNEL=="wwan*", RUN+="/bin/sh -c 'echo Y > /sys/class/net/%k/qmi/raw_ip'"
+ACTION=="add", KERNEL=="cdc-wdm0", TAG+="systemd", ENV{SYSTEMD_WANTS}="qmi.service"
+endef
+export UDEV_CONFIG
+
 qmi-service:
 define QMI_SERVICE
 [Unit]
-Description=Start QMI data session
-After=dev-cdc\x2dwdm0.device sys-subsystem-net-devices-wwan0.device
-Requires=dev-cdc\x2dwdm0.device
+Description=Bring up QMI data session
+DefaultDependencies=no
 BindsTo=dev-cdc\x2dwdm0.device
+After=dev-cdc\x2dwdm0.device
 
 [Service]
 Type=oneshot
 RemainAfterExit=yes
 
-ExecStartPre=/bin/sh -c 'echo Y > /sys/class/net/wwan0/qmi/raw_ip'
-ExecStart=/usr/bin/qmicli -d /dev/cdc-wdm0 --device-open-proxy --wds-start-network="ip-type=4" --client-no-release-cid
-ExecStop=/usr/bin/qmicli -d /dev/cdc-wdm0 --device-open-proxy --wds-stop-network=0xffffffff
+ExecStart=networkctl down wwan0 ; /usr/bin/qmicli -d /dev/cdc-wdm0 --device-open-proxy --wds-start-network="ip-type=4" --client-no-release-cid ; networkctl up wwan0
+ExecStop=networkctl down wwan0 ; /usr/bin/qmicli -d /dev/cdc-wdm0 --device-open-proxy --wds-stop-network=0xffffffff
 
 Restart=on-failure
 RestartSec=5
-
-[Install]
-WantedBy=multi-user.target
 endef
 export QMI_SERVICE
 
@@ -60,8 +68,8 @@ define QMI_MONITOR_TIMER
 Description=Monitor QMI connection
 
 [Timer]
-OnBootSec=30
-OnUnitActiveSec=30
+OnBootSec=300
+OnUnitActiveSec=300
 
 [Install]
 WantedBy=timers.target