relay: expire any rendezvous channel after one hour

src/wormhole/servers/relay.py

@@ -1,14 +1,18 @@
 from __future__ import print_function
-import re, json
+import re, json, time
 from collections import defaultdict
 from twisted.python import log
 from twisted.internet import protocol
-from twisted.application import strports, service
+from twisted.application import strports, service, internet
 from twisted.web import server, static, resource, http
 
 SECONDS = 1.0
+MINUTE = 60*SECONDS
+HOUR = 60*MINUTE
 MB = 1000*1000
 
+CHANNEL_EXPIRATION_TIME = 1*HOUR
+
 class Channel(resource.Resource):
     isLeaf = True
 
@@ -22,6 +26,7 @@ class Channel(resource.Resource):
         resource.Resource.__init__(self)
         self.channel_id = channel_id
         self.relay = relay
+        self.expire_at = time.time() + CHANNEL_EXPIRATION_TIME
         self.sides = set()
         self.messages = {"pake": defaultdict(list), # side -> [strings]
                          "data": defaultdict(list), # side -> [strings]
@@ -83,6 +88,14 @@ class Relay(resource.Resource):
         self.channels = {}
         self.next_channel = 1
 
+    def prune_old_channels(self):
+        now = time.time()
+        for channel_id in list(self.channels):
+            c = self.channels[channel_id]
+            if c.expire_at < now:
+                log.msg("expiring %d" % channel_id)
+                self.free_child(channel_id)
+
     def getChild(self, path, request):
         if path == "allocate":
             # be more clever later. Rotate through 1-99 unless they're all
@@ -243,8 +256,10 @@ class RelayServer(service.MultiService):
         site = server.Site(self.root)
         self.relayport_service = strports.service(relayport, site)
         self.relayport_service.setServiceParent(self)
-        self.relay = Relay() # for tests
+        self.relay = Relay() # accessible from tests
         self.root.putChild("relay", self.relay)
+        t = internet.TimerService(5*MINUTE, self.relay.prune_old_channels)
+        t.setServiceParent(self)
         self.transit = Transit()
         self.transit.setServiceParent(self) # for the timer
         self.transport_service = strports.service(transitport, self.transit)