networks: Configure wireless BSSID, band, channel

Select the frequency band (2.4 GHz vs. 5 GHz) is a prerequisite for
selecting the channel.  Channel selection is useful primarily as follow:

- Restrict to a particular access point when multiple access points use
  the same SSID (AP name) but are available on different frequencies.

- Configure for a particular ad-hoc mesh network.

- Setup multiple access points from a single FreedomBox on multiple
  channels to maximize the throughput and number of simultaneous
  clients.

Ability to specify a particular BSSID will help associate with a
particular access point when multiple access points use the same
SSID (AP name).  This is also makes it slightly harder to trick clients
into connection to a malicious device.  Also configuring BATMAN-adv
seems to require setting a particular BSSID.

plinth/modules/networks/forms.py

@@ -188,8 +188,9 @@ class PPPoEForm(EthernetForm):
 
 class WifiForm(ConnectionForm):
     """Form to create/edit a Wi-Fi connection."""
-    field_order = ['name', 'interface', 'zone', 'ssid', 'mode', 'auth_mode',
-                   'passphrase', 'ipv4_method', 'ipv4_address', 'ipv4_netmask',
+    field_order = ['name', 'interface', 'zone', 'ssid', 'mode', 'band',
+                   'channel', 'bssid', 'auth_mode', 'passphrase',
+                   'ipv4_method', 'ipv4_address', 'ipv4_netmask',
                    'ipv4_gateway', 'ipv4_dns', 'ipv4_second_dns']
 
     ssid = forms.CharField(
@@ -200,6 +201,27 @@ class WifiForm(ConnectionForm):
         choices=[('infrastructure', _('Infrastructure')),
                  ('ap', _('Access Point')),
                  ('adhoc', _('Ad-hoc'))])
+    band = forms.ChoiceField(
+        label=_('Frequency Band'),
+        choices=[('auto', _('Automatic')),
+                 ('a', _('A (5 GHz)')),
+                 ('bg', _('B/G (2.4 GHz)'))])
+    channel = forms.IntegerField(
+        label=_('Channel'),
+        help_text=_('Optional value. Wireless channel in the selected '
+                    'frequency band to restrict to. Blank or 0 value means '
+                    'automatic selection.'),
+        min_value=0,
+        max_value=255,
+        required=False)
+    bssid = forms.RegexField(
+        label=_('BSSID'),
+        help_text=_('Optional value. Unique identifier for the access point. '
+                    'When connecting to an access point, connect only if the '
+                    'BSSID of the access point matches the one provided. '
+                    'Example: 00:11:22:aa:bb:cc.'),
+        regex=r'^([0-9A-Fa-f]{2}:){5}[0-9A-Fa-f]{2}$',
+        required=False)
     auth_mode = forms.ChoiceField(
         label=_('Authentication Mode'),
         help_text=_('Select WPA if the wireless network is secured and \
@@ -224,6 +246,9 @@ requires clients to have the password to connect.'),
         settings['wireless'] = {
             'ssid': self.cleaned_data['ssid'],
             'mode': self.cleaned_data['mode'],
+            'band': self.cleaned_data['band'],
+            'channel': self.cleaned_data['channel'],
+            'bssid': self.cleaned_data['bssid'],
             'auth_mode': self.cleaned_data['auth_mode'],
             'passphrase': self.cleaned_data['passphrase'],
         }

plinth/modules/networks/networks.py

@@ -164,6 +164,9 @@ def edit(request, uuid):
             settings_wireless = connection.get_setting_wireless()
             form_data['ssid'] = settings_wireless.get_ssid().get_data()
             form_data['mode'] = settings_wireless.get_mode()
+            form_data['band'] = settings_wireless.get_band() or 'auto'
+            form_data['channel'] = settings_wireless.get_channel()
+            form_data['bssid'] = settings_wireless.get_bssid()
             try:
                 wifi_sec = connection.get_setting_wireless_security()
                 if wifi_sec:
@@ -328,6 +331,7 @@ def add_wifi(request, ssid=None, interface_name=None):
                      'zone': 'external',
                      'ssid': ssid,
                      'mode': 'infrastructure',
+                     'band': 'auto',
                      'auth_mode': 'wpa',
                      'ipv4_method': 'auto'}
 

plinth/network.py

@@ -383,6 +383,14 @@ def _update_wireless_settings(connection, wireless):
     ssid_gbytes = glib.Bytes.new(wireless['ssid'].encode())
     settings.set_property(nm.SETTING_WIRELESS_SSID, ssid_gbytes)
     settings.set_property(nm.SETTING_WIRELESS_MODE, wireless['mode'])
+    band = wireless['band'] if wireless['band'] != 'auto' else None
+    settings.set_property(nm.SETTING_WIRELESS_BAND, band)
+    channel = wireless['channel']
+    if wireless['band'] == 'auto' or not wireless['channel']:
+        channel = 0
+
+    settings.set_property(nm.SETTING_WIRELESS_CHANNEL, channel)
+    settings.set_property(nm.SETTING_WIRELESS_BSSID, wireless['bssid'] or None)
 
     # Wireless Security
     if wireless['auth_mode'] == 'wpa' and wireless['passphrase']: