Improve timezone gateway selector. Closes #2894

It allows to use multiple gateways in openvpn for redundancy.

3 files changed, 32 insertions, 26 deletions

diff --git a/changes/feature_2877-improve_gateway_selector b/changes/feature_2877-improve_gateway_selector
new file mode 100644
index 00000000..5162a09e
--- /dev/null
+++ b/changes/feature_2877-improve_gateway_selector
@@ -0,0 +1 @@
+  o Improve gateway selector based on timezone. It allows to use multiple gateways in openvpn for redundancy. Closes #2894.
diff --git a/src/leap/services/eip/eipconfig.py b/src/leap/services/eip/eipconfig.py
index f7d03963..a85fe64a 100644
--- a/src/leap/services/eip/eipconfig.py
+++ b/src/leap/services/eip/eipconfig.py
@@ -52,33 +52,32 @@ class VPNGatewaySelector(object):
         self._set_local_offset()
         self._eipconfig = eipconfig
 
-    def _get_best_gateway(self):
+    def get_gateways(self):
         """
-        Returns index of the closest gateway, using timezones offsets.
+        Returns the 4 best gateways, sorted by timezone proximity.
 
-        :rtype: int
+        :rtype: list of IPv4Address or IPv6Address object.
         """
-        best_gateway = (-1, 99)  # gateway, distance
+        gateways_timezones = []
         locations = self._eipconfig.get_locations()
         gateways = self._eipconfig.get_gateways()
+
         for idx, gateway in enumerate(gateways):
-            gateway_offset = int(locations[gateway['location']]['timezone'])
-            gateway_distance = self._get_timezone_distance(gateway_offset)
-            if gateway_distance < best_gateway[1]:
-                best_gateway = (idx, gateway_distance)
+            gateway_location = gateway.get('location')
+            gateway_distance = 99  # if hasn't location -> should go last
 
-        return best_gateway[0]
+            if gateway_location is not None:
+                gw_offset = int(locations[gateway['location']]['timezone'])
+                gateway_distance = self._get_timezone_distance(gw_offset)
 
-    def get_best_gateway_ip(self):
-        """
-        Returns the ip of the best possible gateway.
+            ip = self._eipconfig.get_gateway_ip(idx)
+            gateways_timezones.append((ip, gateway_distance))
 
-        :rtype: An IPv4Address or IPv6Address object.
-        """
-        best_gateway = self._get_best_gateway()
-        gateway_ip = self._eipconfig.get_gateway_ip(best_gateway)
+        gateways_timezones = sorted(gateways_timezones,
+                                    key=lambda gw: gw[1])[:4]
 
-        return gateway_ip
+        gateways = [ip for ip, dist in gateways_timezones]
+        return gateways
 
     def _get_timezone_distance(self, offset):
         '''
diff --git a/src/leap/services/eip/vpnlaunchers.py b/src/leap/services/eip/vpnlaunchers.py
index fa2989bc..fdc863c6 100644
--- a/src/leap/services/eip/vpnlaunchers.py
+++ b/src/leap/services/eip/vpnlaunchers.py
@@ -229,16 +229,18 @@ class LinuxVPNLauncher(VPNLauncher):
         # TODO: handle verbosity
 
         gateway_selector = VPNGatewaySelector(eipconfig)
-        gateway_ip = gateway_selector.get_best_gateway_ip()
+        gateways = gateway_selector.get_gateways()
 
-        logger.debug("Using gateway ip %s" % (gateway_ip,))
+        logger.debug("Using gateways ips: {}".format(', '.join(gateways)))
+
+        for gw in gateways:
+            args += ['--remote', gw, '1194', 'udp']
 
         args += [
             '--client',
             '--dev', 'tun',
             '--persist-tun',
             '--persist-key',
-            '--remote', gateway_ip, '1194', 'udp',
             '--tls-client',
             '--remote-cert-tls',
             'server'
@@ -393,16 +395,18 @@ class DarwinVPNLauncher(VPNLauncher):
         # TODO: handle verbosity
 
         gateway_selector = VPNGatewaySelector(eipconfig)
-        gateway_ip = gateway_selector.get_best_gateway_ip()
+        gateways = gateway_selector.get_gateways()
+
+        logger.debug("Using gateways ips: {}".format(', '.join(gateways)))
 
-        logger.debug("Using gateway ip %s" % (gateway_ip,))
+        for gw in gateways:
+            args += ['--remote', gw, '1194', 'udp']
 
         args += [
             '--client',
             '--dev', 'tun',
             '--persist-tun',
             '--persist-key',
-            '--remote', gateway_ip, '1194', 'udp',
             '--tls-client',
             '--remote-cert-tls',
             'server'
@@ -534,16 +538,18 @@ class WindowsVPNLauncher(VPNLauncher):
         # TODO: handle verbosity
 
         gateway_selector = VPNGatewaySelector(eipconfig)
-        gateway_ip = gateway_selector.get_best_gateway_ip()
+        gateways = gateway_selector.get_gateways()
+
+        logger.debug("Using gateways ips: {}".format(', '.join(gateways)))
 
-        logger.debug("Using gateway ip %s" % (gateway_ip,))
+        for gw in gateways:
+            args += ['--remote', gw, '1194', 'udp']
 
         args += [
             '--client',
             '--dev', 'tun',
             '--persist-tun',
             '--persist-key',
-            '--remote', gateway_ip, '1194', 'udp',
             '--tls-client',
             '--remote-cert-tls',
             'server'