Draft: Implement initial functionality

This implements initial functionality to use QMI modem(s) as wireless WAN.

Only one modem at the time acting as WAN is currently supported. The expected setup is just one modem - i.e. Turris router with LTE kit - but code can handle multiple attached modems.

In that scenario all detected modems are offered as a choice, but there can be only one selected and designated as WAN.

Following API functions are currently implemented:

• get_settings
• update_settings

This MR depends on functionality implemented in: foris-controller!125

foris_controller_backends/wwan/__init__.py

@@ -12,7 +12,7 @@ import turrishw
 from foris_controller.exceptions import BackendCommandFailed
 from foris_controller_backends.cmdline import BaseCmdLine
 from foris_controller_backends.maintain import MaintainCommands
-from foris_controller_backends.networks import NetworksUci
+from foris_controller_backends.networks import NetworksWanUci
 from foris_controller_backends.uci import (
     UciBackend,
     get_option_named,
@@ -45,6 +45,7 @@ class WWanUci:
 
             res = WWanUci._match_wwan_interface(if_name, dev_no, qmi_ctl_device, sim_status)
             if not res:
+                # We could not find existing uci configuration for given device -> return defaults
                 qmi_devices.append({
                     "id": dev_no,
                     "enabled": False,
@@ -54,7 +55,7 @@ class WWanUci:
                     "pincode": "",
                     "authentication": {"auth_type": "none"},
                     "sim_status": sim_status,
-                })  # default/empty values
+                })
             else:
                 qmi_devices.append(res)
 
@@ -100,7 +101,7 @@ class WWanUci:
         else:
             extra_auth = {"auth_type": "none"}
 
-        enabled = NetworksUci.is_designated_as_wan(if_name)
+        enabled = NetworksWanUci.is_designated_as_wan(if_name)
 
         return {
             "id": dev_no,
@@ -163,12 +164,18 @@ class WWanUci:
                 backend.set_option("network", wdev_name, "password", password)
 
             # switch uplink to wireless wan
-            NetworksUci.set_wan_firewall_zone_interfaces(backend, (wdev_name,))
+            NetworksWanUci.set_wan_firewall_zone_interfaces(backend, (wdev_name,))
 
         MaintainCommands().restart_network()
 
         return True
 
+    @staticmethod
+    def disable_wwan(id: int):
+        with UciBackend() as backend:
+            # reset to default wan
+            NetworksWanUci.set_wan_firewall_zone_interfaces(backend)
+
     @staticmethod
     def _get_id_from_dev_name(dev_name: str) -> typing.Optional[int]:
         """Extract device id (number) from its name.
@@ -192,6 +199,14 @@ class WWanCmd(BaseCmdLine):
         just whether SIM card is 'working' or not.
         """
         try:
+            # There are two utilities to fetch information from QMI modem - 'qmicli' and 'uqmi'.
+            # 'qmicli' is more recent and it looks like it is actively
+            # maintained, but at the moment it can produce only text output.
+            # 'uqmi' is older and it could get stuck while trying to fetch SIM
+            # state informations on certain modems. But it produces json output.
+            #
+            # Therefore I decided to go with 'uqmi' and set timeout for its
+            # process, in case it gets stuck.
             stdout, _ = WWanCmd._run_command_and_check_retval(
                 ["/sbin/uqmi", "-d", ctl_device, "--uim-get-sim-state"],
                 expected_retval=0, timeout=20
@@ -213,7 +228,7 @@ class WWanCmd(BaseCmdLine):
         if not pin_status:
             return "failure"  # no SIM detected
 
-        if pin_status != "verified":
+        if pin_status not in {"verified","disabled"}:
             return "failure"  # SIM is not active or bad pin?
 
         return "ok"