[feature] allow manual gateway selection for vpn

For now, the way to select a gateway is to add a section in
bitmaskd.cfg:

  [vpn_prefs]
  locations = ["frankfurt", "seattle__wa"]
  countries = ["DE", "US"]

Note that the location indication has priority over country code.

This will be exposed by the UI in release 0.11

- Resolves: #8855

7 files changed, 153 insertions, 9 deletions

diff --git a/docs/changelog.rst b/docs/changelog.rst
index c89f51e..6f94d87 100644
--- a/docs/changelog.rst
+++ b/docs/changelog.rst
@@ -5,6 +5,7 @@ Changelog
 
 Features
 ~~~~~~~~
+- Initial cli port of the legacy vpn code
 - `#8112 <https://0xacab.org/leap/bitmask-dev/issues/8112>`_: Check validity of key signature
 - `#8755 <https://0xacab.org/leap/bitmask-dev/issues/8755>`_: Add account based keymanagement API
 - `#8770 <https://0xacab.org/leap/bitmask-dev/issues/8770>`_: Simplify mail status in the cli
@@ -16,7 +17,7 @@ Features
 - `#8049 <https://0xacab.org/leap/bitmask-dev/issues/8049>`_: Restart the VPN automatically
 - `#8852 <https://0xacab.org/leap/bitmask-dev/issues/8852>`_: Stop the vpn (and all services) when application is shut down
 - `#8804 <https://0xacab.org/leap/bitmask-dev/issues/8804>`_: Automatic selection of gateways, based on user timezone
-- Initial cli port of the legacy vpn code
+- `#8855 <https://0xacab.org/leap/bitmask-dev/issues/8855>`_: Manual override for the vpn gateway selection
 - Add VPN API to bitmask.js
 - Add vpn get_cert command
 - Indicate a successful/failure OpenPGP header import
diff --git a/docs/index.rst b/docs/index.rst
index ecd9d60..bc509ca 100644
--- a/docs/index.rst
+++ b/docs/index.rst
@@ -66,6 +66,7 @@ Contents
    hacking/index
    bundles/index
    cli/index
+   vpn/index
    core/index
    bonafide/index
    keymanager/index
diff --git a/docs/vpn/index.rst b/docs/vpn/index.rst
new file mode 100644
index 0000000..7bb4799
--- /dev/null
+++ b/docs/vpn/index.rst
@@ -0,0 +1,39 @@
+:LastChangedDate: $LastChangedDate$
+:LastChangedRevision: $LastChangedRevision$
+:LastChangedBy: $LastChangedBy$
+
+.. _vpn:
+
+
+Bitmask VPN
+================================
+
+The Bitmask VPN Module
+
+Gateway Selection
+-----------------------------------
+
+By default, the Gateway Selector will apply a heuristic based on the configured
+timezone of the system.  This will choose the closest gateway based on the
+timezones that the provider states in the ``eip-config.json`` file.
+
+If the locations section is not properly set by the provider, or if the user
+wants to manually override the selection, the only way to do this for the
+``0.10`` version of Bitmask is to add a section to the ``bitmaskd.cfg``
+configuration file::
+
+  [vpn_prefs]
+  locations = ["rio__br"]
+  countries = ["BR", "AR", "UY"]
+
+Take into account that the locations entry has precedence over the country codes enumeration.
+
+Also, the normalization is done so that any non-alphabetic character is substituted by an underscore ('``_``).
+
+You can list all the configured locations using the CLI::
+
+  % bitmaskctl vpn list
+  demo.bitmask.net      [DE] Frankfurt (UTC+1)
+  demo.bitmask.net      [US] Seattle, WA (UTC-7)
+
+This manual override functionality will be exposed through the UI and the CLI in release ``0.11``.
diff --git a/src/leap/bitmask/cli/command.py b/src/leap/bitmask/cli/command.py
index 1daadc5..5586d09 100644
--- a/src/leap/bitmask/cli/command.py
+++ b/src/leap/bitmask/cli/command.py
@@ -54,7 +54,7 @@ def default_dict_printer(result):
 
     for key, value in result.items():
         if isinstance(value, list):
-            if isinstance(value[0], list):
+            if value and isinstance(value[0], list):
                 value = map(lambda l: ' '.join(l), value)
                 for item in value:
                     pprint('\t' + item)
diff --git a/src/leap/bitmask/vpn/gateways.py b/src/leap/bitmask/vpn/gateways.py
index 950e37c..92367c3 100644
--- a/src/leap/bitmask/vpn/gateways.py
+++ b/src/leap/bitmask/vpn/gateways.py
@@ -18,7 +18,7 @@
 """
 Gateway Selection
 """
-
+import copy
 import logging
 import os
 import re
@@ -27,24 +27,49 @@ import time
 from leap.common.config import get_path_prefix
 
 
+def _normalized(label):
+    return label.lower().replace(',', '_').replace(' ', '_')
+
+
 class GatewaySelector(object):
 
     # http://www.timeanddate.com/time/map/
     equivalent_timezones = {13: -11, 14: -10}
 
-    def __init__(self, gateways=None, locations=None, tz_offset=None):
+    def __init__(self, gateways=None, locations=None, tz_offset=None, preferred=None):
         '''
         Constructor for GatewaySelector.
 
+        By default, we will use a Time Zone Heuristic to choose the closest
+        gateway to the user.
+
+        If the user specified something in the 'vpn_prefs' section of
+        bitmaskd.cfg, we will passed a dictionary here with entries for
+        'countries' and 'locations', in the form of a list. The 'locations'
+        entry has preference over the 'countries' one.
+
+        :param gateways: an unordered list of all the available gateways, read
+                         from the eip-config file.
+        :type gateways: list
+        :param locations: a dictionary with the locations, as read from the
+                          eip-config file
+        :type locations: dict
         :param tz_offset: use this offset as a local distance to GMT.
         :type tz_offset: int
+        :param preferred: a dictionary containing the country code (cc) and the
+                          locations (locations) manually preferred by the user.
+        :type preferred: dict
         '''
         if gateways is None:
             gateways = []
         if locations is None:
             locations = {}
+        if preferred is None:
+            preferred = {}
         self.gateways = gateways
         self.locations = locations
+        self.preferred = preferred
+
         self._local_offset = tz_offset
         if tz_offset is None:
             tz_offset = self._get_local_offset()
@@ -90,7 +115,35 @@ class GatewaySelector(object):
         result = []
         for ip, distance, label, country in gateways_timezones:
             result.append((label, ip, country))
-        return result
+
+        filtered = self.apply_user_preferences(result)
+        return filtered 
+
+    def apply_user_preferences(self, options):
+        """
+        We re-sort the pre-sorted list of gateway options, according with the
+        user's preferences.
+
+        Location has preference over the Country Code indication.
+        """
+        applied = []
+        presorted = copy.copy(options)
+        for location in self.preferred.get('loc', []):
+            for index, data in enumerate(presorted):
+                label, ip, country = data
+                if _normalized(label) == _normalized(location):
+                    applied.append((label, ip, country))
+                    presorted.pop(index)
+
+        for cc in self.preferred.get('cc', []):
+            for index, data in enumerate(presorted):
+                label, ip, country = data
+                if _normalized(country) == _normalized(cc):
+                    applied.append((label, ip, country))
+                    presorted.pop(index)
+        if presorted:
+            applied += presorted 
+        return applied
 
     def get_gateways_country_code(self):
         country_codes = {}
diff --git a/src/leap/bitmask/vpn/service.py b/src/leap/bitmask/vpn/service.py
index b0dcba8..d2f952e 100644
--- a/src/leap/bitmask/vpn/service.py
+++ b/src/leap/bitmask/vpn/service.py
@@ -19,7 +19,7 @@
 """
 VPN service declaration.
 """
-
+import json
 import os
 
 from time import strftime
@@ -133,6 +133,7 @@ class VPNService(HookableService):
         return {'result': 'vpn stopped'}
 
     def do_status(self):
+        # TODO - add the current gateway and CC to the status
         childrenStatus = {
             'vpn': {'status': 'off', 'error': None},
             'firewall': {'status': 'off', 'error': None},
@@ -220,10 +221,21 @@ class VPNService(HookableService):
         bonafide = self.parent.getServiceNamed('bonafide')
         config = yield bonafide.do_provider_read(provider, 'eip')
 
-        sorted_gateways = GatewaySelector(
-            config.gateways, config.locations).select_gateways()
+        try:
+            _cco = self.parent.get_config('vpn_prefs', 'countries', "")
+            pref_cco = json.loads(_cco)
+        except ValueError:
+            pref_cco = []
+        try:
+            _loc = self.parent.get_config('vpn_prefs', 'locations', "")
+            pref_loc = json.loads(_loc)
+        except ValueError:
+            pref_loc = []
 
-        # TODO - add manual gateway selection ability.
+        sorted_gateways = GatewaySelector(
+            config.gateways, config.locations,
+            preferred={'cc': pref_cco, 'loc': pref_loc}
+            ).select_gateways()
 
         extra_flags = config.openvpn_configuration
 
diff --git a/tests/unit/vpn/test_gateways.py b/tests/unit/vpn/test_gateways.py
index cc7fbca..58b2676 100644
--- a/tests/unit/vpn/test_gateways.py
+++ b/tests/unit/vpn/test_gateways.py
@@ -126,3 +126,41 @@ class GatewaySelectorTestCase(unittest.TestCase):
             14)
         gateways = selector.select_gateways()
         assert gateways == [ips[4], ips[2], ips[3], ips[1]]
+
+    def test_apply_user_preferences(self):
+        preferred = {
+            'loc': ['anarres', 'paris__fr', 'montevideo'],
+            'cc': ['BR', 'AR', 'UY'],
+        }
+        selector = GatewaySelector(preferred=preferred)
+        pre = [
+            ('Seattle', '1.1.1.1', 'US'),
+            ('Rio de Janeiro', '1.1.1.1', 'BR'),
+            ('Montevideo', '1.1.1.1', 'UY'),
+            ('Cordoba', '1.1.1.1', 'AR')]
+        ordered = selector.apply_user_preferences(pre)
+        locations = [x[0] for x in ordered]
+        # first the preferred location, then order by country
+        assert locations == ['Montevideo', 'Rio de Janeiro', 'Cordoba', 'Seattle']
+
+        pre = [
+            ('Seattle', '', ''),
+            ('Montevideo', '', ''),
+            ('Paris, FR', '', ''),
+            ('AnaRreS', '', '')]
+        ordered = selector.apply_user_preferences(pre)
+        locations = [x[0] for x in ordered]
+        # first the preferred location, then order by country (test normalization)
+        assert locations == ['AnaRreS', 'Paris, FR', 'Montevideo', 'Seattle']
+
+        pre = [
+            ('Rio De Janeiro', '', 'BR'),
+            ('Tacuarembo', '', 'UY'),
+            ('Sao Paulo', '', 'BR'),
+            ('Cordoba', '', 'AR')]
+        ordered = selector.apply_user_preferences(pre)
+        locations = [x[0] for x in ordered]
+        # no matching location, order by country
+        assert locations == ['Rio De Janeiro', 'Sao Paulo', 'Cordoba', 'Tacuarembo']
+
+