privacy: only store coarse timestamps in the usage table

src/wormhole/scripts/runner.py

@@ -41,6 +41,9 @@ sp_start.add_argument("--transit", default="tcp:3001", metavar="tcp:PORT",
                       help="endpoint specification for the transit-relay port")
 sp_start.add_argument("--advertise-version", metavar="VERSION",
                       help="version to recommend to clients")
+sp_start.add_argument("--blur-usage", default=None, type=int,
+                      metavar="SECONDS",
+                      help="round logged access times to improve privacy")
 sp_start.add_argument("-n", "--no-daemon", action="store_true")
 #sp_start.add_argument("twistd_args", nargs="*", default=None,
 #                      metavar="[TWISTD-ARGS..]",
@@ -61,6 +64,9 @@ sp_restart.add_argument("--transit", default="tcp:3001", metavar="tcp:PORT",
                         help="endpoint specification for the transit-relay port")
 sp_restart.add_argument("--advertise-version", metavar="VERSION",
                         help="version to recommend to clients")
+sp_restart.add_argument("--blur-usage", default=None, type=int,
+                        metavar="SECONDS",
+                        help="round logged access times to improve privacy")
 sp_restart.add_argument("-n", "--no-daemon", action="store_true")
 sp_restart.set_defaults(func=cmd_server.restart_server)
 

src/wormhole/servers/cmd_server.py

@@ -11,7 +11,7 @@ class MyPlugin:
         from .server import RelayServer
         return RelayServer(self.args.rendezvous, self.args.transit,
                            self.args.advertise_version,
-                           "relay.sqlite")
+                           "relay.sqlite", self.args.blur_usage)
 
 def start_server(args):
     from twisted.python import usage

src/wormhole/servers/relay_server.py

@@ -207,10 +207,11 @@ class Deallocator(RelayResource):
 
 
 class Channel:
-    def __init__(self, app, db, welcome, appid, channelid):
+    def __init__(self, app, db, welcome, blur_usage, appid, channelid):
         self._app = app
         self._db = db
         self._welcome = welcome
+        self._blur_usage = blur_usage
         self._appid = appid
         self._channelid = channelid
         self._listeners = set() # callbacks that take JSONable object
@@ -297,6 +298,8 @@ class Channel:
 
     def _store_summary(self, summary):
         (started, result, total_time, waiting_time) = summary
+        if self._blur_usage:
+            started = self._blur_usage * (started // self._blur_usage)
         self._db.execute("INSERT INTO `usage`"
                          " (`type`, `started`, `result`,"
                          "  `total_time`, `waiting_time`)"
@@ -382,9 +385,10 @@ class Channel:
 
 
 class AppNamespace:
-    def __init__(self, db, welcome, appid):
+    def __init__(self, db, welcome, blur_usage, appid):
         self._db = db
         self._welcome = welcome
+        self._blur_usage = blur_usage
         self._appid = appid
         self._channels = {}
 
@@ -420,6 +424,7 @@ class AppNamespace:
         if not channelid in self._channels:
             log.msg("spawning #%d for appid %s" % (channelid, self._appid))
             self._channels[channelid] = Channel(self, self._db, self._welcome,
+                                                self._blur_usage,
                                                 self._appid, channelid)
         return self._channels[channelid]
 
@@ -448,11 +453,12 @@ class AppNamespace:
         return bool(self._channels)
 
 class Relay(resource.Resource, service.MultiService):
-    def __init__(self, db, welcome):
+    def __init__(self, db, welcome, blur_usage):
         resource.Resource.__init__(self)
         service.MultiService.__init__(self)
         self._db = db
         self._welcome = welcome
+        self._blur_usage = blur_usage
         self._apps = {}
         t = internet.TimerService(EXPIRATION_CHECK_PERIOD, self.prune)
         t.setServiceParent(self)
@@ -476,7 +482,8 @@ class Relay(resource.Resource, service.MultiService):
         assert isinstance(appid, type(u""))
         if not appid in self._apps:
             log.msg("spawning appid %s" % (appid,))
-            self._apps[appid] = AppNamespace(self._db, self._welcome, appid)
+            self._apps[appid] = AppNamespace(self._db, self._welcome,
+                                             self._blur_usage, appid)
         return self._apps[appid]
 
     def prune(self):

src/wormhole/servers/server.py

@@ -1,4 +1,5 @@
 from __future__ import print_function
+from twisted.python import log
 from twisted.internet import reactor, endpoints
 from twisted.application import service
 from twisted.web import server, static, resource
@@ -16,8 +17,9 @@ class Root(resource.Resource):
 
 class RelayServer(service.MultiService):
     def __init__(self, relayport, transitport, advertise_version,
-                 db_url=":memory:"):
+                 db_url=":memory:", blur_usage=None):
         service.MultiService.__init__(self)
+        self._blur_usage = blur_usage
         self.db = get_db(db_url)
         welcome = {
             "current_version": __version__,
@@ -35,11 +37,18 @@ class RelayServer(service.MultiService):
         r = endpoints.serverFromString(reactor, relayport)
         self.relayport_service = ServerEndpointService(r, site)
         self.relayport_service.setServiceParent(self)
-        self.relay = Relay(self.db, welcome) # accessible from tests
+        self.relay = Relay(self.db, welcome, blur_usage) # accessible from tests
         self.root.putChild(b"wormhole-relay", self.relay)
         if transitport:
-            self.transit = Transit(self.db)
+            self.transit = Transit(self.db, blur_usage)
             self.transit.setServiceParent(self) # for the timer
             t = endpoints.serverFromString(reactor, transitport)
             self.transport_service = ServerEndpointService(t, self.transit)
             self.transport_service.setServiceParent(self)
+    def startService(self):
+        service.MultiService.startService(self)
+        log.msg("Wormhole relay server (Rendezvous and Transit) running")
+        if self._blur_usage:
+            log.msg("blurring access times to %d seconds" % self._blur_usage)
+        else:
+            log.msg("not blurring access times")

src/wormhole/servers/transit_server.py

@@ -148,9 +148,10 @@ class Transit(protocol.ServerFactory, service.MultiService):
     MAXTIME = 60*SECONDS
     protocol = TransitConnection
 
-    def __init__(self, db):
+    def __init__(self, db, blur_usage):
         service.MultiService.__init__(self)
         self._db = db
+        self._blur_usage = blur_usage
         self._pending_requests = {} # token -> TransitConnection
         self._active_connections = set() # TransitConnection
 
@@ -170,6 +171,8 @@ class Transit(protocol.ServerFactory, service.MultiService):
     def recordUsage(self, started, result, total_bytes,
                     total_time, waiting_time):
         log.msg("Transit.recordUsage (%dB)" % total_bytes)
+        if self._blur_usage:
+            started = self._blur_usage * (started // self._blur_usage)
         self._db.execute("INSERT INTO `usage`"
                          " (`type`, `started`, `result`, `total_bytes`,"
                          "  `total_time`, `waiting_time`)"

src/wormhole/test/test_server.py

@@ -363,7 +363,7 @@ class OneEventAtATime:
 
 class Summary(unittest.TestCase):
     def test_summarize(self):
-        c = relay_server.Channel(None, None, None, None, None)
+        c = relay_server.Channel(None, None, None, None, None, None)
         A = relay_server.ALLOCATE
         D = relay_server.DEALLOCATE