Merge tag '0.3.0' into debian

Tag leap.common version 0.3.0

17 files changed, 1406 insertions, 553 deletions

diff --git a/src/leap/common/__init__.py b/src/leap/common/__init__.py
index 2b30715..3946fe8 100644
--- a/src/leap/common/__init__.py
+++ b/src/leap/common/__init__.py
@@ -16,4 +16,4 @@ except ImportError:
 
 __all__ = ["certs", "check", "files", "events"]
 
-__version__ = "0.2.5"
+__version__ = "0.3.0"
diff --git a/src/leap/common/check.py b/src/leap/common/check.py
index a2d39a6..82da5ff 100644
--- a/src/leap/common/check.py
+++ b/src/leap/common/check.py
@@ -18,7 +18,6 @@
 Set of functions to help checking situations
 """
 
-import inspect
 import logging
 import traceback
 
@@ -39,9 +38,11 @@ def leap_assert(condition, message=""):
     if not condition:
         logger.error("Bug: %s" % (message,))
         try:
-            frame = inspect.currentframe()
-            stack_trace = traceback.format_stack(frame)
-            logger.error(''.join(stack_trace))
+            for formatted_line in traceback.format_list(
+                    traceback.extract_stack()[:-1]):
+                for line in formatted_line.split("\n"):
+                    if len(line.strip()) > 0:
+                        logger.error(line)
         except Exception as e:
             logger.error("Bug in leap_assert: %r" % (e,))
     assert condition, message
@@ -59,3 +60,20 @@ def leap_assert_type(var, expectedType):
     leap_assert(isinstance(var, expectedType),
                 "Expected type %r instead of %r" %
                 (expectedType, type(var)))
+
+
+def leap_check(condition, message="", exception=Exception):
+    """
+    Asserts the condition and displays the message if that's not
+    met. It also logs the error and its backtrace.
+
+    :param condition: condition to check
+    :type condition: bool
+    :param message: message to display if the condition isn't met
+    :type message: str
+    :param exception: the exception to raise in case of condition being false.
+    :type exception: Exception
+    """
+    if not condition:
+        logger.error(message)
+        raise exception(message)
diff --git a/src/leap/common/config/baseconfig.py b/src/leap/common/config/baseconfig.py
index e6bd9c4..e310bc0 100644
--- a/src/leap/common/config/baseconfig.py
+++ b/src/leap/common/config/baseconfig.py
@@ -26,7 +26,7 @@ import os
 
 from abc import ABCMeta, abstractmethod
 
-from leap.common.check import leap_assert
+from leap.common.check import leap_assert, leap_check
 from leap.common.files import mkdir_p
 from leap.common.config.pluggableconfig import PluggableConfig
 from leap.common.config.prefixers import get_platform_prefixer
@@ -34,6 +34,12 @@ from leap.common.config.prefixers import get_platform_prefixer
 logger = logging.getLogger(__name__)
 
 
+class NonExistingSchema(Exception):
+    """
+    Raised if the schema needed to verify the config is None.
+    """
+
+
 class BaseConfig:
     """
     Abstract base class for any JSON based configuration.
@@ -55,13 +61,27 @@ class BaseConfig:
     def __init__(self):
         self._data = {}
         self._config_checker = None
+        self._api_version = None
 
     @abstractmethod
+    def _get_schema(self):
+        """
+        Returns the schema corresponding to the version given.
+
+        :rtype: dict or None if the version is not supported.
+        """
+        pass
+
     def _get_spec(self):
         """
         Returns the spec object for the specific configuration.
+
+        :rtype: dict or None if the version is not supported.
         """
-        return None
+        leap_assert(self._api_version is not None,
+                    "You should set the API version.")
+
+        return self._get_schema()
 
     def _safe_get_value(self, key):
         """
@@ -73,6 +93,17 @@ class BaseConfig:
         leap_assert(self._config_checker, "Load the config first")
         return self._config_checker.config.get(key, None)
 
+    def set_api_version(self, version):
+        """
+        Sets the supported api version.
+
+        :param api_version: the version of the api supported by the provider.
+        :type api_version: str
+        """
+        self._api_version = version
+        leap_assert(self._get_schema() is not None,
+                    "Version %s is not supported." % (version, ))
+
     def get_path_prefix(self):
         """
         Returns the platform dependant path prefixer
@@ -112,6 +143,7 @@ class BaseConfig:
     def load(self, path="", data=None, mtime=None, relative=True):
         """
         Loads the configuration from disk.
+        It may raise NonExistingSchema exception.
 
         :param path: if relative=True, this is a relative path
                      to configuration. The absolute path
@@ -131,8 +163,12 @@ class BaseConfig:
         else:
             config_path = path
 
+        schema = self._get_spec()
+        leap_check(schema is not None,
+                   "There is no schema to use.", NonExistingSchema)
+
         self._config_checker = PluggableConfig(format="json")
-        self._config_checker.options = copy.deepcopy(self._get_spec())
+        self._config_checker.options = copy.deepcopy(schema)
 
         try:
             if data is None:
@@ -155,26 +191,39 @@ class LocalizedKey(object):
     def __init__(self, func, **kwargs):
         self._func = func
 
-    def __call__(self, instance, lang="en"):
+    def __call__(self, instance, lang=None):
         """
         Tries to return the string for the specified language, otherwise
-        informs the problem and returns an empty string.
+        returns the default language string.
 
         :param lang: language code
         :type lang: str
 
         :return: localized value from the possible values returned by
                  self._func
+                 It returns None in case that the provider does not provides
+                 a matching pair of default_language and string for
+                 that language.
+                 e.g.:
+                     'default_language': 'es',
+                     'description': {'en': 'test description'}
+                Note that the json schema can't check that.
         """
         descriptions = self._func(instance)
-        description_lang = ""
-        config_lang = "en"
+        config_lang = instance.get_default_language()
+        if lang is None:
+            lang = config_lang
+
         for key in descriptions.keys():
             if lang.startswith(key):
                 config_lang = key
                 break
 
-        description_lang = descriptions[config_lang]
+        description_lang = descriptions.get(config_lang)
+        if description_lang is None:
+            logger.error("There is a misconfiguration in the "
+                         "provider's language strings.")
+
         return description_lang
 
     def __get__(self, instance, instancetype):
diff --git a/src/leap/common/config/prefixers.py b/src/leap/common/config/prefixers.py
index 050d4cd..9a5b043 100644
--- a/src/leap/common/config/prefixers.py
+++ b/src/leap/common/config/prefixers.py
@@ -95,7 +95,7 @@ class DarwinPrefixer(Prefixer):
         config_dir = BaseDirectory.xdg_config_home
         if not standalone:
             return config_dir
-        return os.getenv(os.getcwd(), "config")
+        return os.path.join(os.getcwd(), "config")
 
 
 class WindowsPrefixer(Prefixer):
diff --git a/src/leap/common/config/tests/test_baseconfig.py b/src/leap/common/config/tests/test_baseconfig.py
new file mode 100644
index 0000000..8a2915e
--- /dev/null
+++ b/src/leap/common/config/tests/test_baseconfig.py
@@ -0,0 +1,268 @@
+# -*- coding: utf-8 -*-
+# test_baseconfig.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Tests for baseconfig
+"""
+import json
+import unittest
+import copy
+
+from leap.common.config.baseconfig import BaseConfig, LocalizedKey
+from leap.common.testing.basetest import BaseLeapTest
+
+from mock import Mock
+
+# reduced eipconfig sample config
+sample_config = {
+    "gateways": [
+    {
+        "capabilities": {
+            "adblock": False,
+            "transport": ["openvpn"],
+            "user_ips": False
+        },
+        "host": "host.dev.example.org",
+    }, {
+        "capabilities": {
+            "adblock": False,
+            "transport": ["openvpn"],
+            "user_ips": False
+        },
+        "host": "host2.dev.example.org",
+    }
+    ],
+    "default_language": "en",
+    "languages": [
+        "en",
+        "es"
+    ],
+    "name": {
+        "en": "Baseconfig testing environment",
+        "es": "Entorno de pruebas de Baseconfig"
+    },
+    "serial": 1,
+    "version": 1
+}
+
+# reduced eipconfig.spec version
+sample_spec = {
+    'description': 'sample eip service config',
+    'type': 'object',
+    'properties': {
+        'serial': {
+            'type': int,
+            'default': 1,
+            'required': ["True"]
+        },
+        'version': {
+            'type': int,
+            'default': 1,
+            'required': ["True"]
+        },
+        "default_language": {
+            'type': unicode,
+            'default': 'en'
+        },
+        'languages': {
+            'type': list,
+            'default': ['en']
+        },
+        'name': {
+            'type': dict,
+            'format': 'translatable',
+            'default': {u'en': u'Test Provider'}
+        },
+        'gateways': {
+            'type': list,
+            'default': [
+                {"capabilities": {
+                    "adblock": True,
+                    "transport": ["openvpn"],
+                    "user_ips": False},
+                 "host": "location.example.org",
+                 }]
+        },
+    }
+}
+
+
+class TestConfig(BaseConfig):
+    """
+    BaseConfig implementation for testing purposes only.
+    """
+    def get_gateways(self):
+        return self._safe_get_value("gateways")
+
+    def get_serial(self):
+        return self._safe_get_value("serial")
+
+    def get_version(self):
+        return self._safe_get_value("version")
+
+    def _get_spec(self):
+        return sample_spec
+
+    def get_default_language(self):
+        return self._safe_get_value("default_language")
+
+    @LocalizedKey
+    def get_name(self):
+        return self._safe_get_value("name")
+
+
+class BaseConfigTest(BaseLeapTest):
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        pass
+
+    def _write_config(self, data):
+        """
+        Helper to write some data to a temp config file.
+
+        :param data: data to be used to save in the config file.
+        :data type: dict (valid json)
+        """
+        self.config_file = self.get_tempfile("config.json")
+        conf = open(self.config_file, "w")
+        conf.write(json.dumps(data))
+        conf.close()
+
+    def _get_config(self, fromfile=False, data=sample_config):
+        """
+        Helper that returns a TestConfig object using the data parameter
+        or a sample data.
+
+        :param fromfile: sets if we should use a file or a string
+        :fromfile type: bool
+        :param data: sets the data to be used to load in the TestConfig object
+        :data type: dict (valid json)
+        :rtype: TestConfig
+        """
+        config = TestConfig()
+
+        loaded = False
+        if fromfile:
+            self._write_config(data)
+            loaded = config.load(self.config_file, relative=False)
+        else:
+            json_string = json.dumps(data)
+            loaded = config.load(data=json_string)
+
+        if not loaded:
+            return None
+
+        return config
+
+    def test_loads_from_file(self):
+        config = self._get_config(fromfile=True)
+        self.assertIsNotNone(config)
+
+    def test_loads_from_data(self):
+        config = self._get_config()
+        self.assertIsNotNone(config)
+
+    def test_load_valid_config_from_file(self):
+        config = self._get_config(fromfile=True)
+        self.assertIsNotNone(config)
+
+        self.assertEqual(config.get_version(), sample_config["version"])
+        self.assertEqual(config.get_serial(), sample_config["serial"])
+        self.assertEqual(config.get_gateways(), sample_config["gateways"])
+
+    def test_load_valid_config_from_data(self):
+        config = self._get_config()
+        self.assertIsNotNone(config)
+
+        self.assertEqual(config.get_version(), sample_config["version"])
+        self.assertEqual(config.get_serial(), sample_config["serial"])
+        self.assertEqual(config.get_gateways(), sample_config["gateways"])
+
+    def test_safe_get_value_no_config(self):
+        config = TestConfig()
+
+        with self.assertRaises(AssertionError):
+            config.get_version()
+
+    def test_safe_get_value_non_existent_value(self):
+        config = self._get_config()
+
+        self.assertIsNone(config._safe_get_value('non-existent-value'))
+
+    def test_loaded(self):
+        config = self._get_config()
+        self.assertTrue(config.loaded())
+
+    def test_not_loaded(self):
+        config = TestConfig()
+        self.assertFalse(config.loaded())
+
+    def test_save_and_load(self):
+        config = self._get_config()
+        config.get_path_prefix = Mock(return_value=self.tempdir)
+        config_file = 'test_config.json'
+        self.assertTrue(config.save([config_file]))
+
+        config_saved = TestConfig()
+        config_file_path = self.get_tempfile(config_file)
+        self.assertTrue(config_saved.load(config_file_path, relative=False))
+
+        self.assertEqual(config.get_version(), config_saved.get_version())
+        self.assertEqual(config.get_serial(), config_saved.get_serial())
+        self.assertEqual(config.get_gateways(), config_saved.get_gateways())
+
+    def test_localizations(self):
+        conf = self._get_config()
+
+        self.assertEqual(conf.get_name(lang='en'), sample_config['name']['en'])
+        self.assertEqual(conf.get_name(lang='es'), sample_config['name']['es'])
+
+    def _localized_config(self, lang):
+        """
+        Helper to change default language of the provider config.
+        """
+        conf = copy.deepcopy(sample_config)
+        conf['default_language'] = lang
+        json_string = json.dumps(conf)
+        config = TestConfig()
+        config.load(data=json_string)
+
+        return config
+
+    def test_default_localization1(self):
+        default_language = sample_config['languages'][0]
+        config = self._localized_config(default_language)
+
+        default_name = sample_config['name'][default_language]
+
+        self.assertEqual(config.get_name(lang='xx'), default_name)
+        self.assertEqual(config.get_name(), default_name)
+
+    def test_default_localization2(self):
+        default_language = sample_config['languages'][1]
+        config = self._localized_config(default_language)
+
+        default_name = sample_config['name'][default_language]
+
+        self.assertEqual(config.get_name(lang='xx'), default_name)
+        self.assertEqual(config.get_name(), default_name)
+
+
+if __name__ == "__main__":
+    unittest.main(verbosity=2)
diff --git a/src/leap/common/crypto.py b/src/leap/common/crypto.py
deleted file mode 100644
index 7f80a8a..0000000
--- a/src/leap/common/crypto.py
+++ /dev/null
@@ -1,114 +0,0 @@
-# -*- coding: utf-8 -*-
-# crypto.py
-# Copyright (C) 2013 LEAP
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-import os
-import binascii
-
-from Crypto.Cipher import AES
-from Crypto.Util import Counter
-from leap.common.check import leap_assert, leap_assert_type
-
-#
-# encryption methods
-#
-
-class EncryptionMethods(object):
-    """
-    Representation of encryption methods that can be used.
-    """
-
-    AES_256_CTR = 'aes-256-ctr'
-
-
-class UnknownEncryptionMethod(Exception):
-    """
-    Raised when trying to encrypt/decrypt with unknown method.
-    """
-    pass
-
-
-#
-# encrypt/decrypt functions
-#
-
-# In the future, we might want to implement other encryption schemes and
-# possibly factor out the actual encryption/decryption routines of the
-# following functions to specific classes, while not changing the API.
-
-def encrypt_sym(data, key, method=EncryptionMethods.AES_256_CTR):
-    """
-    Encrypt C{data} with C{key}, using C{method} encryption method.
-
-    :param data: The data to be encrypted.
-    :type data: str
-    :param key: The key used to encrypt C{data} (must be 256 bits long).
-    :type key: str
-    :param method: The encryption method to use.
-    :type method: str
-
-    :return: A tuple with the initial value and the encrypted data.
-    :rtype: (long, str)
-    """
-    leap_assert_type(key, str)
-
-    # AES-256 in CTR mode
-    if method == EncryptionMethods.AES_256_CTR:
-        leap_assert(
-            len(key) == 32,  # 32 x 8 = 256 bits.
-            'Wrong key size: %s bits (must be 256 bits long).' % (len(key)*8))
-        iv = os.urandom(8)
-        ctr = Counter.new(64, prefix=iv)
-        cipher = AES.new(key=key, mode=AES.MODE_CTR, counter=ctr)
-        return binascii.b2a_base64(iv), cipher.encrypt(data)
-
-    # raise if method is unknown
-    raise UnknownEncryptionMethod('Unkwnown method: %s' % method)
-
-
-def decrypt_sym(data, key, method=EncryptionMethods.AES_256_CTR, **kwargs):
-    """
-    Decrypt C{data} with C{key} using C{method} encryption method.
-
-    :param data: The data to be decrypted.
-    :type data: str
-    :param key: The key used to decrypt C{data} (must be 256 bits long).
-    :type key: str
-    :param method: The encryption method to use.
-    :type method: str
-    :param kwargs: Other parameters specific to each encryption method.
-    :type kwargs: dict
-
-    :return: The decrypted data.
-    :rtype: str
-    """
-    leap_assert_type(key, str)
-
-    # AES-256 in CTR mode
-    if method == EncryptionMethods.AES_256_CTR:
-        # assert params
-        leap_assert(
-            len(key) == 32,  # 32 x 8 = 256 bits.
-            'Wrong key size: %s (must be 256 bits long).' % len(key))
-        leap_assert(
-            'iv' in kwargs,
-            'AES-256-CTR needs an initial value given as.')
-        ctr = Counter.new(64, prefix=binascii.a2b_base64(kwargs['iv']))
-        cipher = AES.new(key=key, mode=AES.MODE_CTR, counter=ctr)
-        return cipher.decrypt(data)
-
-    # raise if method is unknown
-    raise UnknownEncryptionMethod('Unkwnown method: %s' % method)
diff --git a/src/leap/common/events/README.rst b/src/leap/common/events/README.rst
index 813be8b..2e7f254 100644
--- a/src/leap/common/events/README.rst
+++ b/src/leap/common/events/README.rst
@@ -1,19 +1,19 @@
 Events mechanism
 ================
 
-The events mechanism allows for "components" to send signal events to each
-other by means of a centralized server. Components can register with the
+The events mechanism allows for clients to send signal events to each
+other by means of a centralized server. Clients can register with the
 server to receive signals of certain types, and they can also send signals to
-the server that will then redistribute these signals to registered components.
+the server that will then redistribute these signals to registered clients.
 
 
 Listening daemons
 -----------------
 
-Both components and the server listen for incoming messages by using a
+Both clients and the server listen for incoming messages by using a
 listening daemon that runs in its own thread. The server daemon has to be
-started explicitly, while components daemon will be started whenever a
-component registers with the server to receive messages.
+started explicitly, while clients daemon will be started whenever a
+client registers with the server to receive messages.
 
 
 How to use it
diff --git a/src/leap/common/events/__init__.py b/src/leap/common/events/__init__.py
index 9fc93ee..6eaf3d4 100644
--- a/src/leap/common/events/__init__.py
+++ b/src/leap/common/events/__init__.py
@@ -16,7 +16,58 @@
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
-An events mechanism that allows for signaling of events between components.
+This is an events mechanism that uses a server to allow for signaling of
+events between clients.
+
+Application components should use the interface available in this file to
+register callbacks to be executed upon receiving specific signals, and to send
+signals to other components.
+
+To register a callback to be executed when a specific event is signaled, use
+leap.common.events.register():
+
+>>> from leap.common.events import register
+>>> from leap.common.events.proto import CLIENT_UID
+>>> register(CLIENT_UID, lambda req: do_something(req))
+
+To signal an event, use leap.common.events.signal():
+
+>>> from leap.common.events import signal
+>>> from leap.common.events.proto import CLIENT_UID
+>>> signal(CLIENT_UID)
+
+
+NOTE ABOUT SYNC/ASYNC REQUESTS:
+
+Clients always communicate with the server, and never between themselves.
+When a client registers a callback for an event, the callback is saved locally
+in the client and the server stores the client socket port in a list
+associated with that event. When a client signals an event, the server
+forwards the signal to all registered client ports, and then each client
+executes its callbacks associated with that event locally.
+
+Each RPC call from a client to the server is followed by a response from the
+server to the client. Calls to register() and signal() (and all other RPC
+calls) can be synchronous or asynchronous meaning if they will or not wait for
+the server's response before returning.
+
+This mechanism was built on top of protobuf.socketrpc, and because of this RPC
+calls are made synchronous or asynchronous in the following way:
+
+  * If RPC calls receive a parameter called `reqcbk`, then the call is made
+    asynchronous. That means that:
+
+        - an eventual `timeout` parameter is not used,
+        - the call returns immediatelly with value None, and
+        - the `reqcbk` callback is executed asynchronously upon the arrival of
+          a response from the server.
+
+  * Otherwise, if the `reqcbk` parameter is None, then the call is made in a
+    synchronous manner:
+
+        - if a response from server arrives within `timeout` milliseconds, the
+          RPC call returns it;
+        - otherwise, the call returns None.
 """
 
 import logging
@@ -24,9 +75,9 @@ import socket
 
 
 from leap.common.events import (
-    events_pb2,
+    events_pb2 as proto,
     server,
-    component,
+    client,
     daemon,
 )
 
@@ -54,17 +105,40 @@ def register(signal, callback, uid=None, replace=False, reqcbk=None,
     :param replace: should an existent callback with same uid be replaced?
     :type replace: bool
     :param reqcbk: a callback to be called when a response from server is
-        received
-    :type reqcbk: function
-        callback(leap.common.events.events_pb2.EventResponse)
+                   received
+    :type reqcbk: function(leap.common.events.events_pb2.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+
+    :return: the response from server for synch calls or nothing for asynch
+        calls.
+    :rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    return client.register(signal, callback, uid, replace, reqcbk, timeout)
+
+
+def unregister(signal, uid=None, reqcbk=None, timeout=1000):
+    """
+    Unregister a callback.
+
+    If C{uid} is specified, unregisters only the callback identified by that
+    unique id. Otherwise, unregisters all callbacks registered for C{signal}.
+
+    :param signal: the signal that causes the callback to be launched
+    :type signal: int (see the `events.proto` file)
+    :param uid: a unique id for the callback
+    :type uid: int
+    :param reqcbk: a callback to be called when a response from server is
+                   received
+    :type reqcbk: function(proto.UnregisterRequest, proto.EventResponse)
     :param timeout: the timeout for synch calls
     :type timeout: int
 
     :return: the response from server for synch calls or nothing for asynch
-        calls
+             calls.
     :rtype: leap.common.events.events_pb2.EventsResponse or None
     """
-    return component.register(signal, callback, uid, replace, reqcbk, timeout)
+    return client.unregister(signal, uid, reqcbk, timeout)
 
 
 def signal(signal, content="", mac_method="", mac="", reqcbk=None,
@@ -87,14 +161,42 @@ def signal(signal, content="", mac_method="", mac="", reqcbk=None,
     :param mac: the content of the auth mac
     :type mac: str
     :param reqcbk: a callback to be called when a response from server is
-        received
-    :type reqcbk: function
-        callback(leap.common.events.events_pb2.EventResponse)
+                   received
+    :type reqcbk: function(proto.SignalRequest, proto.EventResponse)
     :param timeout: the timeout for synch calls
     :type timeout: int
 
     :return: the response from server for synch calls or nothing for asynch
-        calls
+             calls.
     :rtype: leap.common.events.events_pb2.EventsResponse or None
     """
-    return component.signal(signal, content, mac_method, mac, reqcbk, timeout)
+    return client.signal(signal, content, mac_method, mac, reqcbk, timeout)
+
+def ping_client(port, reqcbk=None, timeout=1000):
+    """
+    Ping a client running in C{port}.
+
+    :param port: the port in which the client should be listening
+    :type port: int
+    :param reqcbk: a callback to be called when a response from client is
+                   received
+    :type reqcbk: function(proto.PingRequest, proto.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+    """
+    return client.ping(port, reqcbk=reqcbk, timeout=timeout)
+
+
+def ping_server(port=server.SERVER_PORT, reqcbk=None, timeout=1000):
+    """
+    Ping the server.
+
+    :param port: the port in which server should be listening
+    :type port: int
+    :param reqcbk: a callback to be called when a response from server is
+                   received
+    :type reqcbk: function(proto.PingRequest, proto.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+    """
+    return server.ping(port, reqcbk=reqcbk, timeout=timeout)
diff --git a/src/leap/common/events/component.py b/src/leap/common/events/client.py
index 9932190..4ae9bff 100644
--- a/src/leap/common/events/component.py
+++ b/src/leap/common/events/client.py
@@ -1,5 +1,5 @@
 # -*- coding: utf-8 -*-
-# component.py
+# client.py
 # Copyright (C) 2013 LEAP
 #
 # This program is free software: you can redistribute it and/or modify
@@ -16,15 +16,15 @@
 # along with this program. If not, see <http://www.gnu.org/licenses/>.
 
 """
-The component end point of the events mechanism.
+The client end point of the events mechanism.
 
-Components are the communicating parties of the events mechanism. They
+Clients are the communicating parties of the events mechanism. They
 communicate by sending messages to a server, which in turn redistributes
-messages to other components.
+messages to other clients.
 
-When a component registers a callback for a given signal, it also tells the
+When a client registers a callback for a given signal, it also tells the
 server that it wants to be notified whenever signals of that type are sent by
-some other component.
+some other client.
 """
 
 
@@ -56,25 +56,26 @@ class CallbackAlreadyRegistered(Exception):
     """
     Raised when trying to register an already registered callback.
     """
+    pass
 
 
-def ensure_component_daemon():
+def ensure_client_daemon():
     """
-    Ensure the component daemon is running and listening for incoming
+    Ensure the client daemon is running and listening for incoming
     messages.
 
     :return: the daemon instance
-    :rtype: EventsComponentDaemon
+    :rtype: EventsClientDaemon
     """
     import time
-    daemon = EventsComponentDaemon.ensure(0)
-    logger.debug('ensure component daemon')
+    daemon = EventsClientDaemon.ensure(0)
+    logger.debug('ensure client daemon')
 
     # Because we use a random port we want to wait until a port is assigned to
-    # local component daemon.
+    # local client daemon.
 
-    while not (EventsComponentDaemon.get_instance() and
-               EventsComponentDaemon.get_instance().get_port()):
+    while not (EventsClientDaemon.get_instance() and
+               EventsClientDaemon.get_instance().get_port()):
         time.sleep(0.1)
     return daemon
 
@@ -94,16 +95,14 @@ def register(signal, callback, uid=None, replace=False, reqcbk=None,
     :param signal: the signal that causes the callback to be launched
     :type signal: int (see the `events.proto` file)
     :param callback: the callback to be called when the signal is received
-    :type callback: function
-        callback(leap.common.events.events_pb2.SignalRequest)
+    :type callback: function(leap.common.events.events_pb2.SignalRequest)
     :param uid: a unique id for the callback
     :type uid: int
     :param replace: should an existent callback with same uid be replaced?
     :type replace: bool
     :param reqcbk: a callback to be called when a response from server is
-        received
-    :type reqcbk: function
-        callback(leap.common.events.events_pb2.EventResponse)
+                   received
+    :type reqcbk: function(proto.RegisterRequest, proto.EventResponse)
     :param timeout: the timeout for synch calls
     :type timeout: int
 
@@ -111,10 +110,10 @@ def register(signal, callback, uid=None, replace=False, reqcbk=None,
     callback identified by the given uid and replace is False.
 
     :return: the response from server for synch calls or nothing for asynch
-        calls
+             calls.
     :rtype: leap.common.events.events_pb2.EventsResponse or None
     """
-    ensure_component_daemon()  # so we can receive registered signals
+    ensure_client_daemon()  # so we can receive registered signals
     # register callback locally
     if signal not in registered_callbacks:
         registered_callbacks[signal] = []
@@ -129,7 +128,7 @@ def register(signal, callback, uid=None, replace=False, reqcbk=None,
     # register callback on server
     request = proto.RegisterRequest()
     request.event = signal
-    request.port = EventsComponentDaemon.get_instance().get_port()
+    request.port = EventsClientDaemon.get_instance().get_port()
     request.mac_method = mac_auth.MacMethod.MAC_NONE
     request.mac = ""
     service = RpcService(proto.EventsServerService_Stub,
@@ -140,6 +139,56 @@ def register(signal, callback, uid=None, replace=False, reqcbk=None,
         str(request)[:40])
     return service.register(request, callback=reqcbk, timeout=timeout)
 
+def unregister(signal, uid=None, reqcbk=None, timeout=1000):
+    """
+    Unregister a callback.
+
+    If C{uid} is specified, unregisters only the callback identified by that
+    unique id. Otherwise, unregisters all callbacks
+
+    :param signal: the signal that causes the callback to be launched
+    :type signal: int (see the `events.proto` file)
+    :param uid: a unique id for the callback
+    :type uid: int
+    :param reqcbk: a callback to be called when a response from server is
+                   received
+    :type reqcbk: function(proto.UnregisterRequest, proto.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+
+    :return: the response from server for synch calls or nothing for asynch
+             calls or None if no callback is registered for that signal or
+             uid.
+    :rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    if signal not in registered_callbacks or not registered_callbacks[signal]:
+        logger.warning("No callback registered for signal %d." % signal)
+        return None
+    # unregister callback locally
+    cbklist = registered_callbacks[signal]
+    if uid is not None:
+        if filter(lambda (cbkuid, _): cbkuid == uid, cbklist) == []:
+            logger.warning("No callback registered for uid %d." % st)
+            return None
+        registered_callbacks[signal] = filter(lambda(x, y): x != uid, cbklist)
+    else:
+        # exclude all callbacks for given signal
+        registered_callbacks[signal] = []
+    # unregister port in server if there are no more callbacks for this signal
+    if not registered_callbacks[signal]:
+        request = proto.UnregisterRequest()
+        request.event = signal
+        request.port = EventsClientDaemon.get_instance().get_port()
+        request.mac_method = mac_auth.MacMethod.MAC_NONE
+        request.mac = ""
+        service = RpcService(proto.EventsServerService_Stub,
+                             server.SERVER_PORT, 'localhost')
+        logger.info(
+            "Sending unregistration request to server on port %s: %s",
+            server.SERVER_PORT,
+            str(request)[:40])
+        return service.unregister(request, callback=reqcbk, timeout=timeout)
+
 
 def signal(signal, content="", mac_method="", mac="", reqcbk=None,
            timeout=1000):
@@ -161,14 +210,13 @@ def signal(signal, content="", mac_method="", mac="", reqcbk=None,
     :param mac: the content of the auth mac
     :type mac: str
     :param reqcbk: a callback to be called when a response from server is
-        received
-    :type reqcbk: function
-        callback(leap.common.events.events_pb2.EventResponse)
+                   received
+    :type reqcbk: function(proto.SignalRequest, proto.EventResponse)
     :param timeout: the timeout for synch calls
     :type timeout: int
 
     :return: the response from server for synch calls or nothing for asynch
-        calls
+             calls.
     :rtype: leap.common.events.events_pb2.EventsResponse or None
     """
     request = proto.SignalRequest()
@@ -182,13 +230,38 @@ def signal(signal, content="", mac_method="", mac="", reqcbk=None,
     return service.signal(request, callback=reqcbk, timeout=timeout)
 
 
-class EventsComponentService(proto.EventsComponentService):
+def ping(port, reqcbk=None, timeout=1000):
     """
-    Service for receiving signal events in components.
+    Ping a client running in C{port}.
+
+    :param port: the port in which the client should be listening
+    :type port: int
+    :param reqcbk: a callback to be called when a response from client is
+                   received
+    :type reqcbk: function(proto.PingRequest, proto.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+
+    :return: the response from client for synch calls or nothing for asynch
+             calls.
+    :rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    request = proto.PingRequest()
+    service = RpcService(
+        proto.EventsClientService_Stub,
+        port,
+        'localhost')
+    logger.info("Pinging a client in port %d..." % port)
+    return service.ping(request, callback=reqcbk, timeout=timeout)
+
+
+class EventsClientService(proto.EventsClientService):
+    """
+    Service for receiving signal events in clients.
     """
 
     def __init__(self):
-        proto.EventsComponentService.__init__(self)
+        proto.EventsClientService.__init__(self)
 
     def signal(self, controller, request, done):
         """
@@ -199,7 +272,7 @@ class EventsComponentService(proto.EventsComponentService):
 
         :param controller: used to mediate a single method call
         :type controller: protobuf.socketrpc.controller.SocketRpcController
-        :param request: the request received from the component
+        :param request: the request received from the client
         :type request: leap.common.events.events_pb2.SignalRequest
         :param done: callback to be called when done
         :type done: protobuf.socketrpc.server.Callback
@@ -219,8 +292,24 @@ class EventsComponentService(proto.EventsComponentService):
         response.status = proto.EventResponse.OK
         done.run(response)
 
+    def ping(self, controller, request, done):
+        """
+        Reply to a ping request.
+
+        :param controller: used to mediate a single method call
+        :type controller: protobuf.socketrpc.controller.SocketRpcController
+        :param request: the request received from the client
+        :type request: leap.common.events.events_pb2.RegisterRequest
+        :param done: callback to be called when done
+        :type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info("Received ping request, sending response.")
+        response = proto.EventResponse()
+        response.status = proto.EventResponse.OK
+        done.run(response)
+
 
-class EventsComponentDaemon(daemon.EventsSingletonDaemon):
+class EventsClientDaemon(daemon.EventsSingletonDaemon):
     """
     A daemon that listens for incoming events from server.
     """
@@ -234,6 +323,6 @@ class EventsComponentDaemon(daemon.EventsSingletonDaemon):
         :type port: int
 
         :return: a daemon instance
-        :rtype: EventsComponentDaemon
+        :rtype: EventsClientDaemon
         """
-        return cls.ensure_service(port, EventsComponentService())
+        return cls.ensure_service(port, EventsClientService())
diff --git a/src/leap/common/events/daemon.py b/src/leap/common/events/daemon.py
index c253948..c4a4189 100644
--- a/src/leap/common/events/daemon.py
+++ b/src/leap/common/events/daemon.py
@@ -43,7 +43,7 @@ class ServiceAlreadyRunningException(Exception):
 
 class EventsRpcServer(SocketRpcServer):
     """
-    RPC server used in server and component interfaces to receive messages.
+    RPC server used in server and client interfaces to receive messages.
     """
 
     def __init__(self, port, host='localhost'):
diff --git a/src/leap/common/events/events.proto b/src/leap/common/events/events.proto
index 447b038..b844f42 100644
--- a/src/leap/common/events/events.proto
+++ b/src/leap/common/events/events.proto
@@ -17,6 +17,9 @@
 package leap.common.events;
 option py_generic_services = true;
 
+
+// These are the events that can be signaled using the events mechanism.
+
 enum Event {
   CLIENT_SESSION_ID = 1;
   CLIENT_UID = 2;
@@ -33,6 +36,10 @@ enum Event {
   RAISE_WINDOW = 13;
 }
 
+
+// A SignalRequest is the type of the message sent from one component to request
+// that a signal be sent to every registered component.
+
 message SignalRequest {
   required Event event = 1;
   required string content = 2;
@@ -42,6 +49,10 @@ message SignalRequest {
   optional bool error_occurred = 6;
 }
 
+
+// A RegisterRequest message tells the server that a component wants to
+// be signaled whenever a specific event occurs.
+
 message RegisterRequest {
   required Event event = 1;
   required int32 port = 2;
@@ -49,6 +60,28 @@ message RegisterRequest {
   required bytes mac = 4;
 }
 
+
+// An UnregisterRequest message tells the server that a component does not
+// want to be signaled when a specific event occurs.
+
+message UnregisterRequest {
+  required Event event = 1;
+  required int32 port = 2;
+  required string mac_method = 3;
+  required bytes mac = 4;
+}
+
+
+// A PingRequest message is used to find out if a server or component is
+// alive.
+
+message PingRequest {
+}
+
+
+// The EventResponse is the message sent back by server and components after
+// they receive other kinds of requests.
+
 message EventResponse {
 
   enum Status {
@@ -61,11 +94,20 @@ message EventResponse {
   optional string result = 2;
 }
 
+
+// The EventsServerService is the service provided by the server.
+
 service EventsServerService {
+  rpc ping(PingRequest) returns (EventResponse);
   rpc register(RegisterRequest) returns (EventResponse);
+  rpc unregister(UnregisterRequest) returns (EventResponse);
   rpc signal(SignalRequest) returns (EventResponse);
 }
 
-service EventsComponentService {
+
+// EventsComponentService is the service provided by components (clients).
+
+service EventsClientService {
+  rpc ping(PingRequest) returns (EventResponse);
   rpc signal(SignalRequest) returns (EventResponse);
 }
diff --git a/src/leap/common/events/events_pb2.py b/src/leap/common/events/events_pb2.py
index a4f1df4..274514c 100644
--- a/src/leap/common/events/events_pb2.py
+++ b/src/leap/common/events/events_pb2.py
@@ -1,85 +1,87 @@
 # Generated by the protocol buffer compiler.  DO NOT EDIT!
+# source: events.proto
 
-from google.protobuf import descriptor
-from google.protobuf import message
-from google.protobuf import reflection
-from google.protobuf import service
+from google.protobuf.internal import enum_type_wrapper
+from google.protobuf import descriptor as _descriptor
+from google.protobuf import message as _message
+from google.protobuf import reflection as _reflection
+from google.protobuf import service as _service
 from google.protobuf import service_reflection
 from google.protobuf import descriptor_pb2
 # @@protoc_insertion_point(imports)
 
 
-DESCRIPTOR = descriptor.FileDescriptor(
+DESCRIPTOR = _descriptor.FileDescriptor(
     name='events.proto',
     package='leap.common.events',
-    serialized_pb='\n\x0c\x65vents.proto\x12\x12leap.common.events\"\x97\x01\n\rSignalRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0f\n\x07\x63ontent\x18\x02 \x02(\t\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\x12\x12\n\nenc_method\x18\x05 \x01(\t\x12\x16\n\x0e\x65rror_occurred\x18\x06 \x01(\x08\"j\n\x0fRegisterRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0c\n\x04port\x18\x02 \x02(\x05\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\"\x82\x01\n\rEventResponse\x12\x38\n\x06status\x18\x01 \x02(\x0e\x32(.leap.common.events.EventResponse.Status\x12\x0e\n\x06result\x18\x02 \x01(\t\"\'\n\x06Status\x12\x06\n\x02OK\x10\x01\x12\n\n\x06UNAUTH\x10\x02\x12\t\n\x05\x45RROR\x10\x03*\xe7\x02\n\x05\x45vent\x12\x15\n\x11\x43LIENT_SESSION_ID\x10\x01\x12\x0e\n\nCLIENT_UID\x10\x02\x12\x19\n\x15SOLEDAD_CREATING_KEYS\x10\x03\x12\x1e\n\x1aSOLEDAD_DONE_CREATING_KEYS\x10\x04\x12\x1a\n\x16SOLEDAD_UPLOADING_KEYS\x10\x05\x12\x1f\n\x1bSOLEDAD_DONE_UPLOADING_KEYS\x10\x06\x12\x1c\n\x18SOLEDAD_DOWNLOADING_KEYS\x10\x07\x12!\n\x1dSOLEDAD_DONE_DOWNLOADING_KEYS\x10\x08\x12\x1c\n\x18SOLEDAD_NEW_DATA_TO_SYNC\x10\t\x12\x1a\n\x16SOLEDAD_DONE_DATA_SYNC\x10\n\x12\x17\n\x13UPDATER_NEW_UPDATES\x10\x0b\x12\x19\n\x15UPDATER_DONE_UPDATING\x10\x0c\x12\x10\n\x0cRAISE_WINDOW\x10\r2\xb9\x01\n\x13\x45ventsServerService\x12R\n\x08register\x12#.leap.common.events.RegisterRequest\x1a!.leap.common.events.EventResponse\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponse2h\n\x16\x45ventsComponentService\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponseB\x03\x90\x01\x01')
+    serialized_pb='\n\x0c\x65vents.proto\x12\x12leap.common.events\"\x97\x01\n\rSignalRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0f\n\x07\x63ontent\x18\x02 \x02(\t\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\x12\x12\n\nenc_method\x18\x05 \x01(\t\x12\x16\n\x0e\x65rror_occurred\x18\x06 \x01(\x08\"j\n\x0fRegisterRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0c\n\x04port\x18\x02 \x02(\x05\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\"l\n\x11UnregisterRequest\x12(\n\x05\x65vent\x18\x01 \x02(\x0e\x32\x19.leap.common.events.Event\x12\x0c\n\x04port\x18\x02 \x02(\x05\x12\x12\n\nmac_method\x18\x03 \x02(\t\x12\x0b\n\x03mac\x18\x04 \x02(\x0c\"\r\n\x0bPingRequest\"\x82\x01\n\rEventResponse\x12\x38\n\x06status\x18\x01 \x02(\x0e\x32(.leap.common.events.EventResponse.Status\x12\x0e\n\x06result\x18\x02 \x01(\t\"\'\n\x06Status\x12\x06\n\x02OK\x10\x01\x12\n\n\x06UNAUTH\x10\x02\x12\t\n\x05\x45RROR\x10\x03*\xe7\x02\n\x05\x45vent\x12\x15\n\x11\x43LIENT_SESSION_ID\x10\x01\x12\x0e\n\nCLIENT_UID\x10\x02\x12\x19\n\x15SOLEDAD_CREATING_KEYS\x10\x03\x12\x1e\n\x1aSOLEDAD_DONE_CREATING_KEYS\x10\x04\x12\x1a\n\x16SOLEDAD_UPLOADING_KEYS\x10\x05\x12\x1f\n\x1bSOLEDAD_DONE_UPLOADING_KEYS\x10\x06\x12\x1c\n\x18SOLEDAD_DOWNLOADING_KEYS\x10\x07\x12!\n\x1dSOLEDAD_DONE_DOWNLOADING_KEYS\x10\x08\x12\x1c\n\x18SOLEDAD_NEW_DATA_TO_SYNC\x10\t\x12\x1a\n\x16SOLEDAD_DONE_DATA_SYNC\x10\n\x12\x17\n\x13UPDATER_NEW_UPDATES\x10\x0b\x12\x19\n\x15UPDATER_DONE_UPDATING\x10\x0c\x12\x10\n\x0cRAISE_WINDOW\x10\r2\xdd\x02\n\x13\x45ventsServerService\x12J\n\x04ping\x12\x1f.leap.common.events.PingRequest\x1a!.leap.common.events.EventResponse\x12R\n\x08register\x12#.leap.common.events.RegisterRequest\x1a!.leap.common.events.EventResponse\x12V\n\nunregister\x12%.leap.common.events.UnregisterRequest\x1a!.leap.common.events.EventResponse\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponse2\xb1\x01\n\x13\x45ventsClientService\x12J\n\x04ping\x12\x1f.leap.common.events.PingRequest\x1a!.leap.common.events.EventResponse\x12N\n\x06signal\x12!.leap.common.events.SignalRequest\x1a!.leap.common.events.EventResponseB\x03\x90\x01\x01')
 
-_EVENT = descriptor.EnumDescriptor(
+_EVENT = _descriptor.EnumDescriptor(
     name='Event',
     full_name='leap.common.events.Event',
     filename=None,
     file=DESCRIPTOR,
     values=[
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='CLIENT_SESSION_ID', index=0, number=1,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='CLIENT_UID', index=1, number=2,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_CREATING_KEYS', index=2, number=3,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_DONE_CREATING_KEYS', index=3, number=4,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_UPLOADING_KEYS', index=4, number=5,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_DONE_UPLOADING_KEYS', index=5, number=6,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_DOWNLOADING_KEYS', index=6, number=7,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_DONE_DOWNLOADING_KEYS', index=7, number=8,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_NEW_DATA_TO_SYNC', index=8, number=9,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='SOLEDAD_DONE_DATA_SYNC', index=9, number=10,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='UPDATER_NEW_UPDATES', index=10, number=11,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='UPDATER_DONE_UPDATING', index=11, number=12,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='RAISE_WINDOW', index=12, number=13,
             options=None,
             type=None),
     ],
     containing_type=None,
     options=None,
-    serialized_start=432,
-    serialized_end=791,
+    serialized_start=557,
+    serialized_end=916,
 )
 
-
+Event = enum_type_wrapper.EnumTypeWrapper(_EVENT)
 CLIENT_SESSION_ID = 1
 CLIENT_UID = 2
 SOLEDAD_CREATING_KEYS = 3
@@ -95,240 +97,349 @@ UPDATER_DONE_UPDATING = 12
 RAISE_WINDOW = 13
 
 
-_EVENTRESPONSE_STATUS = descriptor.EnumDescriptor(
+_EVENTRESPONSE_STATUS = _descriptor.EnumDescriptor(
     name='Status',
     full_name='leap.common.events.EventResponse.Status',
     filename=None,
     file=DESCRIPTOR,
     values=[
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='OK', index=0, number=1,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='UNAUTH', index=1, number=2,
             options=None,
             type=None),
-        descriptor.EnumValueDescriptor(
+        _descriptor.EnumValueDescriptor(
             name='ERROR', index=2, number=3,
             options=None,
             type=None),
     ],
     containing_type=None,
     options=None,
-    serialized_start=390,
-    serialized_end=429,
+    serialized_start=515,
+    serialized_end=554,
 )
 
 
-_SIGNALREQUEST = descriptor.Descriptor(
+_SIGNALREQUEST = _descriptor.Descriptor(
     name='SignalRequest',
     full_name='leap.common.events.SignalRequest',
     filename=None,
     file=DESCRIPTOR,
     containing_type=None,
     fields=[
-        descriptor.FieldDescriptor(
+        _descriptor.FieldDescriptor(
             name='event', full_name='leap.common.events.SignalRequest.event', index=0,
             number=1, type=14, cpp_type=8, label=2,
             has_default_value=False, default_value=1,
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='content', full_name='leap.common.events.SignalRequest.content', index=1,
-      number=2, type=9, cpp_type=9, label=2,
-      has_default_value=False, default_value=unicode("", "utf-8"),
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='mac_method', full_name='leap.common.events.SignalRequest.mac_method', index=2,
-      number=3, type=9, cpp_type=9, label=2,
-      has_default_value=False, default_value=unicode("", "utf-8"),
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='mac', full_name='leap.common.events.SignalRequest.mac', index=3,
-      number=4, type=12, cpp_type=9, label=2,
-      has_default_value=False, default_value="",
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='enc_method', full_name='leap.common.events.SignalRequest.enc_method', index=4,
-      number=5, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=unicode("", "utf-8"),
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='error_occurred', full_name='leap.common.events.SignalRequest.error_occurred', index=5,
-      number=6, type=8, cpp_type=7, label=1,
-      has_default_value=False, default_value=False,
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-  ],
-  extensions=[
-  ],
-  nested_types=[],
-  enum_types=[
-  ],
-  options=None,
-  is_extendable=False,
-  extension_ranges=[],
-  serialized_start=37,
-  serialized_end=188,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='content', full_name='leap.common.events.SignalRequest.content', index=1,
+            number=2, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac_method', full_name='leap.common.events.SignalRequest.mac_method', index=2,
+            number=3, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac', full_name='leap.common.events.SignalRequest.mac', index=3,
+            number=4, type=12, cpp_type=9, label=2,
+            has_default_value=False, default_value="",
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='enc_method', full_name='leap.common.events.SignalRequest.enc_method', index=4,
+            number=5, type=9, cpp_type=9, label=1,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='error_occurred', full_name='leap.common.events.SignalRequest.error_occurred', index=5,
+            number=6, type=8, cpp_type=7, label=1,
+            has_default_value=False, default_value=False,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=37,
+    serialized_end=188,
+)
+
+
+_REGISTERREQUEST = _descriptor.Descriptor(
+    name='RegisterRequest',
+    full_name='leap.common.events.RegisterRequest',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        _descriptor.FieldDescriptor(
+            name='event', full_name='leap.common.events.RegisterRequest.event', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='port', full_name='leap.common.events.RegisterRequest.port', index=1,
+            number=2, type=5, cpp_type=1, label=2,
+            has_default_value=False, default_value=0,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac_method', full_name='leap.common.events.RegisterRequest.mac_method', index=2,
+            number=3, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac', full_name='leap.common.events.RegisterRequest.mac', index=3,
+            number=4, type=12, cpp_type=9, label=2,
+            has_default_value=False, default_value="",
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=190,
+    serialized_end=296,
+)
+
+
+_UNREGISTERREQUEST = _descriptor.Descriptor(
+    name='UnregisterRequest',
+    full_name='leap.common.events.UnregisterRequest',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        _descriptor.FieldDescriptor(
+            name='event', full_name='leap.common.events.UnregisterRequest.event', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='port', full_name='leap.common.events.UnregisterRequest.port', index=1,
+            number=2, type=5, cpp_type=1, label=2,
+            has_default_value=False, default_value=0,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac_method', full_name='leap.common.events.UnregisterRequest.mac_method', index=2,
+            number=3, type=9, cpp_type=9, label=2,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='mac', full_name='leap.common.events.UnregisterRequest.mac', index=3,
+            number=4, type=12, cpp_type=9, label=2,
+            has_default_value=False, default_value="",
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=298,
+    serialized_end=406,
 )
 
 
-_REGISTERREQUEST = descriptor.Descriptor(
-  name='RegisterRequest',
-  full_name='leap.common.events.RegisterRequest',
-  filename=None,
-  file=DESCRIPTOR,
-  containing_type=None,
-  fields=[
-    descriptor.FieldDescriptor(
-      name='event', full_name='leap.common.events.RegisterRequest.event', index=0,
-      number=1, type=14, cpp_type=8, label=2,
-      has_default_value=False, default_value=1,
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='port', full_name='leap.common.events.RegisterRequest.port', index=1,
-      number=2, type=5, cpp_type=1, label=2,
-      has_default_value=False, default_value=0,
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='mac_method', full_name='leap.common.events.RegisterRequest.mac_method', index=2,
-      number=3, type=9, cpp_type=9, label=2,
-      has_default_value=False, default_value=unicode("", "utf-8"),
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='mac', full_name='leap.common.events.RegisterRequest.mac', index=3,
-      number=4, type=12, cpp_type=9, label=2,
-      has_default_value=False, default_value="",
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-  ],
-  extensions=[
-  ],
-  nested_types=[],
-  enum_types=[
-  ],
-  options=None,
-  is_extendable=False,
-  extension_ranges=[],
-  serialized_start=190,
-  serialized_end=296,
+_PINGREQUEST = _descriptor.Descriptor(
+    name='PingRequest',
+    full_name='leap.common.events.PingRequest',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=408,
+    serialized_end=421,
 )
 
 
-_EVENTRESPONSE = descriptor.Descriptor(
-  name='EventResponse',
-  full_name='leap.common.events.EventResponse',
-  filename=None,
-  file=DESCRIPTOR,
-  containing_type=None,
-  fields=[
-    descriptor.FieldDescriptor(
-      name='status', full_name='leap.common.events.EventResponse.status', index=0,
-      number=1, type=14, cpp_type=8, label=2,
-      has_default_value=False, default_value=1,
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-    descriptor.FieldDescriptor(
-      name='result', full_name='leap.common.events.EventResponse.result', index=1,
-      number=2, type=9, cpp_type=9, label=1,
-      has_default_value=False, default_value=unicode("", "utf-8"),
-      message_type=None, enum_type=None, containing_type=None,
-      is_extension=False, extension_scope=None,
-      options=None),
-  ],
-  extensions=[
-  ],
-  nested_types=[],
-  enum_types=[
-    _EVENTRESPONSE_STATUS,
-  ],
-  options=None,
-  is_extendable=False,
-  extension_ranges=[],
-  serialized_start=299,
-  serialized_end=429,
+_EVENTRESPONSE = _descriptor.Descriptor(
+    name='EventResponse',
+    full_name='leap.common.events.EventResponse',
+    filename=None,
+    file=DESCRIPTOR,
+    containing_type=None,
+    fields=[
+        _descriptor.FieldDescriptor(
+            name='status', full_name='leap.common.events.EventResponse.status', index=0,
+            number=1, type=14, cpp_type=8, label=2,
+            has_default_value=False, default_value=1,
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+        _descriptor.FieldDescriptor(
+            name='result', full_name='leap.common.events.EventResponse.result', index=1,
+            number=2, type=9, cpp_type=9, label=1,
+            has_default_value=False, default_value=unicode("", "utf-8"),
+            message_type=None, enum_type=None, containing_type=None,
+            is_extension=False, extension_scope=None,
+            options=None),
+    ],
+    extensions=[
+    ],
+    nested_types=[],
+    enum_types=[
+        _EVENTRESPONSE_STATUS,
+    ],
+    options=None,
+    is_extendable=False,
+    extension_ranges=[],
+    serialized_start=424,
+    serialized_end=554,
 )
 
 _SIGNALREQUEST.fields_by_name['event'].enum_type = _EVENT
 _REGISTERREQUEST.fields_by_name['event'].enum_type = _EVENT
+_UNREGISTERREQUEST.fields_by_name['event'].enum_type = _EVENT
 _EVENTRESPONSE.fields_by_name['status'].enum_type = _EVENTRESPONSE_STATUS
-_EVENTRESPONSE_STATUS.containing_type = _EVENTRESPONSE;
+_EVENTRESPONSE_STATUS.containing_type = _EVENTRESPONSE
 DESCRIPTOR.message_types_by_name['SignalRequest'] = _SIGNALREQUEST
 DESCRIPTOR.message_types_by_name['RegisterRequest'] = _REGISTERREQUEST
+DESCRIPTOR.message_types_by_name['UnregisterRequest'] = _UNREGISTERREQUEST
+DESCRIPTOR.message_types_by_name['PingRequest'] = _PINGREQUEST
 DESCRIPTOR.message_types_by_name['EventResponse'] = _EVENTRESPONSE
 
 
-class SignalRequest(message.Message):
-    __metaclass__ = reflection.GeneratedProtocolMessageType
+class SignalRequest(_message.Message):
+    __metaclass__ = _reflection.GeneratedProtocolMessageType
     DESCRIPTOR = _SIGNALREQUEST
 
     # @@protoc_insertion_point(class_scope:leap.common.events.SignalRequest)
 
 
-class RegisterRequest(message.Message):
-    __metaclass__ = reflection.GeneratedProtocolMessageType
+class RegisterRequest(_message.Message):
+    __metaclass__ = _reflection.GeneratedProtocolMessageType
     DESCRIPTOR = _REGISTERREQUEST
 
     # @@protoc_insertion_point(class_scope:leap.common.events.RegisterRequest)
 
 
-class EventResponse(message.Message):
-    __metaclass__ = reflection.GeneratedProtocolMessageType
+class UnregisterRequest(_message.Message):
+    __metaclass__ = _reflection.GeneratedProtocolMessageType
+    DESCRIPTOR = _UNREGISTERREQUEST
+
+    # @@protoc_insertion_point(class_scope:leap.common.events.UnregisterRequest)
+
+
+class PingRequest(_message.Message):
+    __metaclass__ = _reflection.GeneratedProtocolMessageType
+    DESCRIPTOR = _PINGREQUEST
+
+    # @@protoc_insertion_point(class_scope:leap.common.events.PingRequest)
+
+
+class EventResponse(_message.Message):
+    __metaclass__ = _reflection.GeneratedProtocolMessageType
     DESCRIPTOR = _EVENTRESPONSE
 
     # @@protoc_insertion_point(class_scope:leap.common.events.EventResponse)
 
 
-_EVENTSSERVERSERVICE = descriptor.ServiceDescriptor(
-  name='EventsServerService',
-  full_name='leap.common.events.EventsServerService',
-  file=DESCRIPTOR,
-  index=0,
-  options=None,
-  serialized_start=794,
-  serialized_end=979,
-  methods=[
-  descriptor.MethodDescriptor(
-    name='register',
-    full_name='leap.common.events.EventsServerService.register',
+DESCRIPTOR.has_options = True
+DESCRIPTOR._options = _descriptor._ParseOptions(
+    descriptor_pb2.FileOptions(), '\220\001\001')
+
+_EVENTSSERVERSERVICE = _descriptor.ServiceDescriptor(
+    name='EventsServerService',
+    full_name='leap.common.events.EventsServerService',
+    file=DESCRIPTOR,
     index=0,
-    containing_service=None,
-    input_type=_REGISTERREQUEST,
-    output_type=_EVENTRESPONSE,
-    options=None,
-  ),
-  descriptor.MethodDescriptor(
-    name='signal',
-    full_name='leap.common.events.EventsServerService.signal',
-    index=1,
-    containing_service=None,
-    input_type=_SIGNALREQUEST,
-    output_type=_EVENTRESPONSE,
     options=None,
-  ),
-])
+    serialized_start=919,
+    serialized_end=1268,
+    methods=[
+        _descriptor.MethodDescriptor(
+            name='ping',
+            full_name='leap.common.events.EventsServerService.ping',
+            index=0,
+            containing_service=None,
+            input_type=_PINGREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+        _descriptor.MethodDescriptor(
+            name='register',
+            full_name='leap.common.events.EventsServerService.register',
+            index=1,
+            containing_service=None,
+            input_type=_REGISTERREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+        _descriptor.MethodDescriptor(
+            name='unregister',
+            full_name='leap.common.events.EventsServerService.unregister',
+            index=2,
+            containing_service=None,
+            input_type=_UNREGISTERREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+        _descriptor.MethodDescriptor(
+            name='signal',
+            full_name='leap.common.events.EventsServerService.signal',
+            index=3,
+            containing_service=None,
+            input_type=_SIGNALREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+    ])
 
 
-class EventsServerService(service.Service):
+class EventsServerService(_service.Service):
     __metaclass__ = service_reflection.GeneratedServiceType
     DESCRIPTOR = _EVENTSSERVERSERVICE
 
@@ -338,34 +449,43 @@ class EventsServerService_Stub(EventsServerService):
     DESCRIPTOR = _EVENTSSERVERSERVICE
 
 
-_EVENTSCOMPONENTSERVICE = descriptor.ServiceDescriptor(
-  name='EventsComponentService',
-  full_name='leap.common.events.EventsComponentService',
-  file=DESCRIPTOR,
-  index=1,
-  options=None,
-  serialized_start=981,
-  serialized_end=1085,
-  methods=[
-  descriptor.MethodDescriptor(
-    name='signal',
-    full_name='leap.common.events.EventsComponentService.signal',
-    index=0,
-    containing_service=None,
-    input_type=_SIGNALREQUEST,
-    output_type=_EVENTRESPONSE,
+_EVENTSCLIENTSERVICE = _descriptor.ServiceDescriptor(
+    name='EventsClientService',
+    full_name='leap.common.events.EventsClientService',
+    file=DESCRIPTOR,
+    index=1,
     options=None,
-  ),
-])
+    serialized_start=1271,
+    serialized_end=1448,
+    methods=[
+        _descriptor.MethodDescriptor(
+            name='ping',
+            full_name='leap.common.events.EventsClientService.ping',
+            index=0,
+            containing_service=None,
+            input_type=_PINGREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+        _descriptor.MethodDescriptor(
+            name='signal',
+            full_name='leap.common.events.EventsClientService.signal',
+            index=1,
+            containing_service=None,
+            input_type=_SIGNALREQUEST,
+            output_type=_EVENTRESPONSE,
+            options=None,
+        ),
+    ])
 
 
-class EventsComponentService(service.Service):
+class EventsClientService(_service.Service):
     __metaclass__ = service_reflection.GeneratedServiceType
-    DESCRIPTOR = _EVENTSCOMPONENTSERVICE
+    DESCRIPTOR = _EVENTSCLIENTSERVICE
 
 
-class EventsComponentService_Stub(EventsComponentService):
+class EventsClientService_Stub(EventsClientService):
     __metaclass__ = service_reflection.GeneratedServiceStubType
-    DESCRIPTOR = _EVENTSCOMPONENTSERVICE
+    DESCRIPTOR = _EVENTSCLIENTSERVICE
 
 # @@protoc_insertion_point(module_scope)
diff --git a/src/leap/common/events/server.py b/src/leap/common/events/server.py
index 1f3a874..59f3454 100644
--- a/src/leap/common/events/server.py
+++ b/src/leap/common/events/server.py
@@ -17,12 +17,12 @@
 """
 A server for the events mechanism.
 
-A server can receive different kinds of requests from components:
+A server can receive different kinds of requests from clients:
 
-  1. Registration request: store component port number to be notified when
+  1. Registration request: store client port number to be notified when
      a specific signal arrives.
 
-  2. Signal request: redistribute the signal to registered components.
+  2. Signal request: redistribute the signal to registered clients.
 """
 import logging
 import socket
@@ -40,12 +40,19 @@ logger = logging.getLogger(__name__)
 
 SERVER_PORT = 8090
 
-# the `registered_components` dictionary below should have the following
+# the `registered_clients` dictionary below should have the following
 # format:
 #
 #     { event_signal: [ port, ... ], ... }
 #
-registered_components = {}
+registered_clients = {}
+
+
+class PortAlreadyTaken(Exception):
+    """
+    Raised when trying to open a server in a port that is already taken.
+    """
+    pass
 
 
 def ensure_server(port=SERVER_PORT):
@@ -60,71 +67,150 @@ def ensure_server(port=SERVER_PORT):
 
     :return: the daemon instance or nothing
     :rtype: EventsServerDaemon or None
+
+    :raise PortAlreadyTaken: Raised if C{port} is already taken by something
+                             that is not an events server.
     """
     try:
+        # check if port is available
         s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
         s.connect(('localhost', port))
         s.close()
-        logger.info('Server is already running on port %d.', port)
-        return None
+        # port is taken, check if there's a server running there
+        response = ping(port)
+        if response is not None and response.status == proto.EventResponse.OK:
+            logger.info('A server is already running on port %d.', port)
+            return None
+        # port is taken, and not by an events server
+        logger.info('Port %d is taken by something not an events server.', port)
+        raise PortAlreadyTaken(port)
     except socket.error:
+        # port is available, run a server
         logger.info('Launching server on port %d.', port)
         return EventsServerDaemon.ensure(port)
 
 
+def ping(port=SERVER_PORT, reqcbk=None, timeout=1000):
+    """
+    Ping the server.
+
+    :param port: the port in which server should be listening
+    :type port: int
+    :param reqcbk: a callback to be called when a response from server is
+                   received
+    :type reqcbk: function(proto.PingRequest, proto.EventResponse)
+    :param timeout: the timeout for synch calls
+    :type timeout: int
+
+    :return: the response from server for synch calls or nothing for asynch
+             calls.
+    :rtype: leap.common.events.events_pb2.EventsResponse or None
+    """
+    request = proto.PingRequest()
+    service = RpcService(
+        proto.EventsServerService_Stub,
+        port,
+        'localhost')
+    logger.info("Pinging server in port %d..." % port)
+    return service.ping(request, callback=reqcbk, timeout=timeout)
+
+
 class EventsServerService(proto.EventsServerService):
     """
-    Service for receiving events in components.
+    Service for receiving events in clients.
     """
 
     def register(self, controller, request, done):
         """
-        Register a component port to be signaled when specific events come in.
+        Register a client port to be signaled when specific events come in.
 
         :param controller: used to mediate a single method call
         :type controller: protobuf.socketrpc.controller.SocketRpcController
-        :param request: the request received from the component
+        :param request: the request received from the client
         :type request: leap.common.events.events_pb2.RegisterRequest
         :param done: callback to be called when done
         :type done: protobuf.socketrpc.server.Callback
         """
         logger.info("Received registration request: %s..." % str(request)[:40])
-        # add component port to signal list
-        if request.event not in registered_components:
-            registered_components[request.event] = set([])
-        registered_components[request.event].add(request.port)
-        # send response back to component
+        # add client port to signal list
+        if request.event not in registered_clients:
+            registered_clients[request.event] = set([])
+        registered_clients[request.event].add(request.port)
+        # send response back to client
 
         logger.debug('sending response back')
         response = proto.EventResponse()
         response.status = proto.EventResponse.OK
         done.run(response)
 
+    def unregister(self, controller, request, done):
+        """
+        Unregister a client port so it will not be signaled when specific
+        events come in.
+
+        :param controller: used to mediate a single method call
+        :type controller: protobuf.socketrpc.controller.SocketRpcController
+        :param request: the request received from the client
+        :type request: leap.common.events.events_pb2.RegisterRequest
+        :param done: callback to be called when done
+        :type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info(
+            "Received unregistration request: %s..." % str(request)[:40])
+        # remove client port from signal list
+        response = proto.EventResponse()
+        if request.event in registered_clients:
+            try:
+                registered_clients[request.event].remove(request.port)
+                response.status = proto.EventResponse.OK
+            except KeyError:
+                response.status = proto.EventsResponse.ERROR
+                response.result = 'Port %d not registered.' % request.port
+        # send response back to client
+        logger.debug('sending response back')
+        done.run(response)
+
     def signal(self, controller, request, done):
         """
-        Perform an RPC call to signal all components registered to receive a
+        Perform an RPC call to signal all clients registered to receive a
         specific signal.
 
         :param controller: used to mediate a single method call
         :type controller: protobuf.socketrpc.controller.SocketRpcController
-        :param request: the request received from the component
+        :param request: the request received from the client
         :type request: leap.common.events.events_pb2.SignalRequest
         :param done: callback to be called when done
         :type done: protobuf.socketrpc.server.Callback
         """
-        logger.info('Received signal from component: %s...', str(request)[:40])
-        # send signal to all registered components
+        logger.info('Received signal from client: %s...', str(request)[:40])
+        # send signal to all registered clients
         # TODO: verify signal auth
-        if request.event in registered_components:
-            for port in registered_components[request.event]:
+        if request.event in registered_clients:
+            for port in registered_clients[request.event]:
 
                 def callback(req, resp):
                     logger.info("Signal received by " + str(port))
 
-                service = RpcService(proto.EventsComponentService_Stub,
+                service = RpcService(proto.EventsClientService_Stub,
                                      port, 'localhost')
                 service.signal(request, callback=callback)
-        # send response back to component
+        # send response back to client
+        response = proto.EventResponse()
+        response.status = proto.EventResponse.OK
+        done.run(response)
+
+    def ping(self, controller, request, done):
+        """
+        Reply to a ping request.
+
+        :param controller: used to mediate a single method call
+        :type controller: protobuf.socketrpc.controller.SocketRpcController
+        :param request: the request received from the client
+        :type request: leap.common.events.events_pb2.RegisterRequest
+        :param done: callback to be called when done
+        :type done: protobuf.socketrpc.server.Callback
+        """
+        logger.info("Received ping request, sending response.")
         response = proto.EventResponse()
         response.status = proto.EventResponse.OK
         done.run(response)
diff --git a/src/leap/common/testing/basetest.py b/src/leap/common/testing/basetest.py
index 8890bf9..54826d5 100644
--- a/src/leap/common/testing/basetest.py
+++ b/src/leap/common/testing/basetest.py
@@ -68,7 +68,8 @@ class BaseLeapTest(unittest.TestCase):
         # safety check! please do not wipe my home...
         # XXX needs to adapt to non-linuces
         leap_assert(
-            cls.tempdir.startswith('/tmp/leap_tests-'),
+            cls.tempdir.startswith('/tmp/leap_tests-') or
+            cls.tempdir.startswith('/var/folder'),
             "beware! tried to remove a dir which does not "
             "live in temporal folder!")
         shutil.rmtree(cls.tempdir)
diff --git a/src/leap/common/tests/test_check.py b/src/leap/common/tests/test_check.py
new file mode 100644
index 0000000..6ce8493
--- /dev/null
+++ b/src/leap/common/tests/test_check.py
@@ -0,0 +1,52 @@
+# -*- coding: utf-8 -*-
+# test_check.py
+# Copyright (C) 2013 LEAP
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+"""
+Tests for:
+    * leap/common/check.py
+"""
+try:
+    import unittest2 as unittest
+except ImportError:
+    import unittest
+
+import mock
+
+from leap.common import check
+
+class CheckTests(unittest.TestCase):
+    def test_raises_on_false_condition(self):
+        with self.assertRaises(AssertionError):
+            check.leap_assert(False, "Condition")
+
+    def test_raises_on_none_condition(self):
+        with self.assertRaises(AssertionError):
+            check.leap_assert(None, "Condition")
+
+    def test_suceeds_with_good_condition(self):
+        check.leap_assert(True, "")
+
+    def test_raises_on_bad_type(self):
+        with self.assertRaises(AssertionError):
+            check.leap_assert_type(42, str)
+
+    def test_succeeds_on_good_type(self):
+        check.leap_assert_type(42, int)
+
+    @mock.patch("traceback.extract_stack", mock.MagicMock(return_value=None))
+    def test_does_not_raise_on_bug(self):
+        with self.assertRaises(AssertionError):
+            check.leap_assert(False, "")
diff --git a/src/leap/common/tests/test_crypto.py b/src/leap/common/tests/test_crypto.py
deleted file mode 100644
index ae7dc71..0000000
--- a/src/leap/common/tests/test_crypto.py
+++ /dev/null
@@ -1,88 +0,0 @@
-## -*- coding: utf-8 -*-
-# test_crypto.py
-# Copyright (C) 2013 LEAP
-#
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-
-"""
-Tests for the crypto submodule.
-"""
-
-
-import os
-import binascii
-
-
-from leap.common.testing.basetest import BaseLeapTest
-from leap.common import crypto
-from Crypto import Random
-
-
-class CryptoTestCase(BaseLeapTest):
-
-    def setUp(self):
-        pass
-
-    def tearDown(self):
-        pass
-
-    def test_encrypt_decrypt_sym(self):
-        # generate 256-bit key
-        key = Random.new().read(32)
-        iv, cyphertext = crypto.encrypt_sym(
-            'data', key,
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertTrue(cyphertext is not None)
-        self.assertTrue(cyphertext != '')
-        self.assertTrue(cyphertext != 'data')
-        plaintext = crypto.decrypt_sym(
-            cyphertext, key, iv=iv,
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertEqual('data', plaintext)
-
-    def test_decrypt_with_wrong_iv_fails(self):
-        key = Random.new().read(32)
-        iv, cyphertext = crypto.encrypt_sym(
-            'data', key,
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertTrue(cyphertext is not None)
-        self.assertTrue(cyphertext != '')
-        self.assertTrue(cyphertext != 'data')
-        # get a different iv by changing the first byte
-        rawiv = binascii.a2b_base64(iv)
-        wrongiv = rawiv
-        while wrongiv == rawiv:
-            wrongiv = os.urandom(1) + rawiv[1:]
-        plaintext = crypto.decrypt_sym(
-            cyphertext, key, iv=binascii.b2a_base64(wrongiv),
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertNotEqual('data', plaintext)
-
-    def test_decrypt_with_wrong_key_fails(self):
-        key = Random.new().read(32)
-        iv, cyphertext = crypto.encrypt_sym(
-            'data', key,
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertTrue(cyphertext is not None)
-        self.assertTrue(cyphertext != '')
-        self.assertTrue(cyphertext != 'data')
-        wrongkey = Random.new().read(32)  # 256-bits key
-        # ensure keys are different in case we are extremely lucky
-        while wrongkey == key:
-            wrongkey = Random.new().read(32)
-        plaintext = crypto.decrypt_sym(
-            cyphertext, wrongkey, iv=iv,
-            method=crypto.EncryptionMethods.AES_256_CTR)
-        self.assertNotEqual('data', plaintext)
diff --git a/src/leap/common/tests/test_events.py b/src/leap/common/tests/test_events.py
index 8c0bd36..0779b2e 100644
--- a/src/leap/common/tests/test_events.py
+++ b/src/leap/common/tests/test_events.py
@@ -18,19 +18,27 @@
 import unittest
 import sets
 import time
+import socket
+import threading
+import random
+
+
+from mock import Mock
 from protobuf.socketrpc import RpcService
 from leap.common import events
 from leap.common.events import (
     server,
-    component,
+    client,
     mac_auth,
 )
 from leap.common.events.events_pb2 import (
     EventsServerService,
     EventsServerService_Stub,
+    EventsClientService_Stub,
     EventResponse,
     SignalRequest,
     RegisterRequest,
+    PingRequest,
     SOLEDAD_CREATING_KEYS,
     CLIENT_UID,
 )
@@ -39,11 +47,6 @@ from leap.common.events.events_pb2 import (
 port = 8090
 
 received = False
-local_callback_executed = False
-
-
-def callback(request, reponse):
-    return True
 
 
 class EventsTestCase(unittest.TestCase):
@@ -51,7 +54,7 @@ class EventsTestCase(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         server.EventsServerDaemon.ensure(8090)
-        cls.callbacks = events.component.registered_callbacks
+        cls.callbacks = events.client.registered_callbacks
 
     @classmethod
     def tearDownClass(cls):
@@ -62,8 +65,8 @@ class EventsTestCase(unittest.TestCase):
         super(EventsTestCase, self).setUp()
 
     def tearDown(self):
-        #events.component.registered_callbacks = {}
-        server.registered_components = {}
+        #events.client.registered_callbacks = {}
+        server.registered_clients = {}
         super(EventsTestCase, self).tearDown()
 
     def test_service_singleton(self):
@@ -76,24 +79,24 @@ class EventsTestCase(unittest.TestCase):
         self.assertEqual(service1, service2,
                          "Can't get singleton class for service.")
 
-    def test_component_register(self):
+    def test_client_register(self):
         """
-        Ensure components can register callbacks.
+        Ensure clients can register callbacks.
         """
         self.assertTrue(1 not in self.callbacks,
                         'There should should be no callback for this signal.')
         events.register(1, lambda x: True)
         self.assertTrue(1 in self.callbacks,
-                        'Could not register signal in local component.')
+                        'Could not register signal in local client.')
         events.register(2, lambda x: True)
         self.assertTrue(1 in self.callbacks,
-                        'Could not register signal in local component.')
+                        'Could not register signal in local client.')
         self.assertTrue(2 in self.callbacks,
-                        'Could not register signal in local component.')
+                        'Could not register signal in local client.')
 
     def test_register_signal_replace(self):
         """
-        Make sure components can replace already registered callbacks.
+        Make sure clients can replace already registered callbacks.
         """
         sig = 3
         cbk = lambda x: True
@@ -120,21 +123,32 @@ class EventsTestCase(unittest.TestCase):
         response = service.signal(request, timeout=1000)
         self.assertEqual(EventResponse.OK, response.status,
                          'Wrong response status.')
-        # test asynch
 
-        def local_callback(request, response):
-            global local_callback_executed
-            local_callback_executed = True
+    def test_signal_executes_callback(self):
+        """
+        Ensure callback is executed upon receiving signal.
+        """
+        sig = CLIENT_UID
+        request = SignalRequest()
+        request.event = sig
+        request.content = 'my signal contents'
+        request.mac_method = mac_auth.MacMethod.MAC_NONE
+        request.mac = ""
+        service = RpcService(EventsServerService_Stub, port, 'localhost')
 
-        events.register(sig, local_callback)
-        service.signal(request, callback=local_callback)
-        time.sleep(0.1)
-        self.assertTrue(local_callback_executed,
-                        'Local callback did not execute.')
+        # register a callback
+        flag = Mock()
+        events.register(sig, lambda req: flag(req.event))
+        # signal
+        response = service.signal(request)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+        time.sleep(1)  # wait for signal to arrive
+        flag.assert_called_once_with(sig)
 
     def test_events_server_service_register(self):
         """
-        Ensure the server can register components to be signaled.
+        Ensure the server can register clients to be signaled.
         """
         sig = 5
         request = RegisterRequest()
@@ -143,42 +157,39 @@ class EventsTestCase(unittest.TestCase):
         request.mac_method = mac_auth.MacMethod.MAC_NONE
         request.mac = ""
         service = RpcService(EventsServerService_Stub, port, 'localhost')
-        complist = server.registered_components
+        complist = server.registered_clients
         self.assertEqual({}, complist,
                          'There should be no registered_ports when '
                          'server has just been created.')
         response = service.register(request, timeout=1000)
         self.assertTrue(sig in complist, "Signal not registered succesfully.")
         self.assertTrue(8091 in complist[sig],
-                        'Failed registering component port.')
+                        'Failed registering client port.')
 
-    def test_component_request_register(self):
+    def test_client_request_register(self):
         """
-        Ensure components can register themselves with server.
+        Ensure clients can register themselves with server.
         """
         sig = 6
-        complist = server.registered_components
+        complist = server.registered_clients
         self.assertTrue(sig not in complist,
-                        'There should be no registered components for this '
+                        'There should be no registered clients for this '
                         'signal.')
         events.register(sig, lambda x: True)
         time.sleep(0.1)
-        port = component.EventsComponentDaemon.get_instance().get_port()
-        self.assertTrue(sig in complist, 'Failed registering component.')
+        port = client.EventsClientDaemon.get_instance().get_port()
+        self.assertTrue(sig in complist, 'Failed registering client.')
         self.assertTrue(port in complist[sig],
-                        'Failed registering component port.')
+                        'Failed registering client port.')
 
-    def test_component_receives_signal(self):
+    def test_client_receives_signal(self):
         """
-        Ensure components can receive signals.
+        Ensure clients can receive signals.
         """
         sig = 7
+        flag = Mock()
 
-        def getsig(param=None):
-            global received
-            received = True
-
-        events.register(sig, getsig)
+        events.register(sig, lambda req: flag(req.event))
         request = SignalRequest()
         request.event = sig
         request.content = ""
@@ -188,13 +199,230 @@ class EventsTestCase(unittest.TestCase):
         response = service.signal(request, timeout=1000)
         self.assertTrue(response is not None, 'Did not receive response.')
         time.sleep(0.5)
-        self.assertTrue(received, 'Did not receive signal back.')
+        flag.assert_called_once_with(sig)
 
-    def test_component_send_signal(self):
+    def test_client_send_signal(self):
         """
-        Ensure components can send signals.
+        Ensure clients can send signals.
         """
         sig = 8
         response = events.signal(sig)
         self.assertTrue(response.status == response.OK,
                         'Received wrong response status when signaling.')
+
+    def test_client_unregister_all(self):
+        """
+        Test that the client can unregister all events for one signal.
+        """
+        sig = CLIENT_UID
+        complist = server.registered_clients
+        events.register(sig, lambda x: True)
+        events.register(sig, lambda x: True)
+        time.sleep(0.1)
+        events.unregister(sig)
+        time.sleep(0.1)
+        port = client.EventsClientDaemon.get_instance().get_port()
+        self.assertFalse(bool(complist[sig]))
+        self.assertTrue(port not in complist[sig])
+
+    def test_client_unregister_by_uid(self):
+        """
+        Test that the client can unregister an event by uid.
+        """
+        sig = CLIENT_UID
+        complist = server.registered_clients
+        events.register(sig, lambda x: True, uid='cbkuid')
+        events.register(sig, lambda x: True, uid='cbkuid2')
+        time.sleep(0.1)
+        events.unregister(sig, uid='cbkuid')
+        time.sleep(0.1)
+        port = client.EventsClientDaemon.get_instance().get_port()
+        self.assertTrue(sig in complist)
+        self.assertTrue(len(complist[sig]) == 1)
+        self.assertTrue(
+            client.registered_callbacks[sig].pop()[0] == 'cbkuid2')
+        self.assertTrue(port in complist[sig])
+
+    def test_server_replies_ping(self):
+        """
+        Ensure server replies to a ping.
+        """
+        request = PingRequest()
+        service = RpcService(EventsServerService_Stub, port, 'localhost')
+        response = service.ping(request, timeout=1000)
+        self.assertIsNotNone(response)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_client_replies_ping(self):
+        """
+        Ensure clients reply to a ping.
+        """
+        daemon = client.ensure_client_daemon()
+        port = daemon.get_port()
+        request = PingRequest()
+        service = RpcService(EventsClientService_Stub, port, 'localhost')
+        response = service.ping(request, timeout=1000)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_server_ping(self):
+        """
+        Ensure the function from server module pings correctly.
+        """
+        response = server.ping()
+        self.assertIsNotNone(response)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_client_ping(self):
+        """
+        Ensure the function from client module pings correctly.
+        """
+        daemon = client.ensure_client_daemon()
+        response = client.ping(daemon.get_port())
+        self.assertIsNotNone(response)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_module_ping_server(self):
+        """
+        Ensure the function from main module pings server correctly.
+        """
+        response = events.ping_server()
+        self.assertIsNotNone(response)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_module_ping_client(self):
+        """
+        Ensure the function from main module pings clients correctly.
+        """
+        daemon = client.ensure_client_daemon()
+        response = events.ping_client(daemon.get_port())
+        self.assertIsNotNone(response)
+        self.assertEqual(EventResponse.OK, response.status,
+                         'Wrong response status.')
+
+    def test_ensure_server_raises_if_port_taken(self):
+        """
+        Verify that server raises an exception if port is already taken.
+        """
+        # get a random free port
+        while True:
+            port = random.randint(1024, 65535)
+            try:
+                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                s.connect(('localhost', port))
+                s.close()
+            except:
+                break
+
+        class PortBlocker(threading.Thread):
+
+            def run(self):
+                conns = 0
+                s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+                s.bind(('localhost', port))
+                s.setblocking(1)
+                s.listen(1)
+                while conns < 2:  # blocks until rece
+                    conns += 1
+                    s.accept()
+                s.close()
+
+        # block the port
+        taker = PortBlocker()
+        taker.start()
+        time.sleep(1)  # wait for thread to start.
+        self.assertRaises(
+            server.PortAlreadyTaken, server.ensure_server, port)
+
+    def test_async_register(self):
+        """
+        Test asynchronous registering of callbacks.
+        """
+        flag = Mock()
+
+        # executed after async register, when response is received from server
+        def reqcbk(request, response):
+            flag(request.event, response.status)
+
+        # callback registered by application
+        def callback(request):
+            pass
+
+        # passing a callback as reqcbk param makes the call asynchronous
+        result = events.register(CLIENT_UID, callback, reqcbk=reqcbk)
+        self.assertIsNone(result)
+        events.signal(CLIENT_UID)
+        time.sleep(1)  # wait for signal to arrive from server
+        flag.assert_called_once_with(CLIENT_UID, EventResponse.OK)
+
+    def test_async_signal(self):
+        """
+        Test asynchronous registering of callbacks.
+        """
+        flag = Mock()
+
+        # executed after async signal, when response is received from server
+        def reqcbk(request, response):
+            flag(request.event, response.status)
+
+        # passing a callback as reqcbk param makes the call asynchronous
+        result = events.signal(CLIENT_UID, reqcbk=reqcbk)
+        self.assertIsNone(result)
+        time.sleep(1)  # wait for signal to arrive from server
+        flag.assert_called_once_with(CLIENT_UID, EventResponse.OK)
+
+    def test_async_unregister(self):
+        """
+        Test asynchronous unregistering of callbacks.
+        """
+        flag = Mock()
+
+        # executed after async signal, when response is received from server
+        def reqcbk(request, response):
+            flag(request.event, response.status)
+
+        # callback registered by application
+        def callback(request):
+            pass
+
+        # passing a callback as reqcbk param makes the call asynchronous
+        events.register(CLIENT_UID, callback)
+        result = events.unregister(CLIENT_UID, reqcbk=reqcbk)
+        self.assertIsNone(result)
+        time.sleep(1)  # wait for signal to arrive from server
+        flag.assert_called_once_with(CLIENT_UID, EventResponse.OK)
+
+    def test_async_ping_server(self):
+        """
+        Test asynchronous pinging of server.
+        """
+        flag = Mock()
+
+        # executed after async signal, when response is received from server
+        def reqcbk(request, response):
+            flag(response.status)
+
+        result = events.ping_server(reqcbk=reqcbk)
+        self.assertIsNone(result)
+        time.sleep(1)  # wait for response to arrive from server.
+        flag.assert_called_once_with(EventResponse.OK)
+
+    def test_async_ping_client(self):
+        """
+        Test asynchronous pinging of client.
+        """
+        flag = Mock()
+
+        # executed after async signal, when response is received from server
+        def reqcbk(request, response):
+            flag(response.status)
+
+        daemon = client.ensure_client_daemon()
+        result = events.ping_client(daemon.get_port(), reqcbk=reqcbk)
+        self.assertIsNone(result)
+        time.sleep(1)  # wait for response to arrive from server.
+        flag.assert_called_once_with(EventResponse.OK)