417 lines
17 KiB
Python
417 lines
17 KiB
Python
from __future__ import print_function
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import re, json, time, random
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from twisted.python import log
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from twisted.internet import protocol
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from twisted.application import strports, service, internet
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from twisted.web import server, static, resource, http
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from .. import __version__
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from ..database import get_db
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SECONDS = 1.0
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MINUTE = 60*SECONDS
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HOUR = 60*MINUTE
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DAY = 24*HOUR
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MB = 1000*1000
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CHANNEL_EXPIRATION_TIME = 1*HOUR
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class EventsProtocol:
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def __init__(self, request):
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self.request = request
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def sendComment(self, comment):
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# this is ignored by clients, but can keep the connection open in the
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# face of firewall/NAT timeouts. It also helps unit tests, since
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# apparently twisted.web.client.Agent doesn't consider the connection
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# to be established until it sees the first byte of the reponse body.
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self.request.write(": %s\n\n" % comment)
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def sendEvent(self, data, name=None, id=None, retry=None):
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if name:
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self.request.write("event: %s\n" % name.encode("utf-8"))
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# e.g. if name=foo, then the client web page should do:
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# (new EventSource(url)).addEventListener("foo", handlerfunc)
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# Note that this basically defaults to "message".
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self.request.write("\n")
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if id:
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self.request.write("id: %s\n" % id.encode("utf-8"))
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self.request.write("\n")
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if retry:
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self.request.write("retry: %d\n" % retry) # milliseconds
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self.request.write("\n")
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for line in data.splitlines():
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self.request.write("data: %s\n" % line.encode("utf-8"))
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self.request.write("\n")
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def stop(self):
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self.request.finish()
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# note: no versions of IE (including the current IE11) support EventSource
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# relay URLs are:
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# GET /list -> {channel-ids: [INT..]}
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# POST /allocate/SIDE -> {channel-id: INT}
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# these return all messages for CHANNEL-ID= and MSGNUM= but SIDE!= :
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# POST /CHANNEL-ID/SIDE/post/MSGNUM {message: STR} -> {messages: [STR..]}
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# POST /CHANNEL-ID/SIDE/poll/MSGNUM -> {messages: [STR..]}
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# GET /CHANNEL-ID/SIDE/poll/MSGNUM (eventsource) -> STR, STR, ..
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# POST /CHANNEL-ID/SIDE/deallocate -> waiting | deleted
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class Channel(resource.Resource):
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isLeaf = True # I handle /CHANNEL-ID/*
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def __init__(self, channel_id, relay, db, welcome):
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resource.Resource.__init__(self)
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self.channel_id = channel_id
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self.relay = relay
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self.db = db
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self.welcome = welcome
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self.expire_at = time.time() + CHANNEL_EXPIRATION_TIME
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self.event_channels = set() # (side, msgnum, ep)
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def render_GET(self, request):
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# rest of URL is: SIDE/poll/MSGNUM
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their_side = request.postpath[0]
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if request.postpath[1] != "poll":
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request.setResponseCode(http.BAD_REQUEST, "GET to wrong URL")
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return "GET is only for /SIDE/poll/MSGNUM"
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their_msgnum = request.postpath[2]
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if "text/event-stream" not in (request.getHeader("accept") or ""):
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request.setResponseCode(http.BAD_REQUEST, "Must use EventSource")
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return "Must use EventSource (Content-Type: text/event-stream)"
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request.setHeader("content-type", "text/event-stream")
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ep = EventsProtocol(request)
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ep.sendEvent(json.dumps(self.welcome), name="welcome")
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handle = (their_side, their_msgnum, ep)
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self.event_channels.add(handle)
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request.notifyFinish().addErrback(self._shutdown, handle)
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for row in self.db.execute("SELECT * FROM `messages`"
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" WHERE `channel_id`=?"
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" ORDER BY `when` ASC",
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(self.channel_id,)).fetchall():
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self.message_added(row["side"], row["msgnum"], row["message"],
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channels=[handle])
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return server.NOT_DONE_YET
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def _shutdown(self, _, handle):
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self.event_channels.discard(handle)
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def message_added(self, msg_side, msg_msgnum, msg_str, channels=None):
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if channels is None:
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channels = self.event_channels
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for (their_side, their_msgnum, their_ep) in channels:
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if msg_side != their_side and msg_msgnum == their_msgnum:
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data = json.dumps({ "side": msg_side, "message": msg_str })
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their_ep.sendEvent(data)
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def render_POST(self, request):
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# rest of URL is: SIDE/(MSGNUM|deallocate)/(post|poll)
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side = request.postpath[0]
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verb = request.postpath[1]
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if verb == "deallocate":
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deleted = self.relay.maybe_free_child(self.channel_id, side)
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if deleted:
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return "deleted\n"
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return "waiting\n"
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if verb not in ("post", "poll"):
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request.setResponseCode(http.BAD_REQUEST)
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return "bad verb, want 'post' or 'poll'\n"
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msgnum = request.postpath[2]
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other_messages = []
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for row in self.db.execute("SELECT `message` FROM `messages`"
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" WHERE `channel_id`=? AND `side`!=?"
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" AND `msgnum`=?"
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" ORDER BY `when` ASC",
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(self.channel_id, side, msgnum)).fetchall():
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other_messages.append(row["message"])
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if verb == "post":
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data = json.load(request.content)
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self.db.execute("INSERT INTO `messages`"
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" (`channel_id`, `side`, `msgnum`, `message`, `when`)"
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" VALUES (?,?,?,?,?)",
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(self.channel_id, side, msgnum, data["message"],
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time.time()))
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self.db.execute("INSERT INTO `allocations`"
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" (`channel_id`, `side`)"
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" VALUES (?,?)",
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(self.channel_id, side))
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self.db.commit()
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self.message_added(side, msgnum, data["message"])
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request.setHeader("content-type", "application/json; charset=utf-8")
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return json.dumps({"welcome": self.welcome,
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"messages": other_messages})+"\n"
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def get_allocated(db):
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c = db.execute("SELECT DISTINCT `channel_id` FROM `allocations`")
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return set([row["channel_id"] for row in c.fetchall()])
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class Allocator(resource.Resource):
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isLeaf = True
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def __init__(self, db, welcome):
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resource.Resource.__init__(self)
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self.db = db
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self.welcome = welcome
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def allocate_channel_id(self):
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allocated = get_allocated(self.db)
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for size in range(1,4): # stick to 1-999 for now
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available = set()
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for cid in range(10**(size-1), 10**size):
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if cid not in allocated:
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available.add(cid)
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if available:
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return random.choice(list(available))
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# ouch, 999 currently allocated. Try random ones for a while.
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for tries in range(1000):
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cid = random.randrange(1000, 1000*1000)
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if cid not in allocated:
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return cid
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raise ValueError("unable to find a free channel-id")
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def render_POST(self, request):
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side = request.postpath[0]
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channel_id = self.allocate_channel_id()
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self.db.execute("INSERT INTO `allocations` VALUES (?,?)",
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(channel_id, side))
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self.db.commit()
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log.msg("allocated #%d, now have %d DB channels" %
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(channel_id, len(get_allocated(self.db))))
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request.setHeader("content-type", "application/json; charset=utf-8")
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return json.dumps({"welcome": self.welcome,
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"channel-id": channel_id})+"\n"
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class ChannelList(resource.Resource):
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def __init__(self, db, welcome):
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resource.Resource.__init__(self)
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self.db = db
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self.welcome = welcome
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def render_GET(self, request):
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c = self.db.execute("SELECT DISTINCT `channel_id` FROM `allocations`")
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allocated = sorted(set([row["channel_id"] for row in c.fetchall()]))
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request.setHeader("content-type", "application/json; charset=utf-8")
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return json.dumps({"welcome": self.welcome,
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"channel-ids": allocated})+"\n"
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class Relay(resource.Resource):
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PRUNE_AGE = 3*DAY # old channels expire after 3 days
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def __init__(self, db, welcome):
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resource.Resource.__init__(self)
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self.db = db
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self.welcome = welcome
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self.channels = {}
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def getChild(self, path, request):
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if path == "allocate":
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return Allocator(self.db, self.welcome)
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if path == "list":
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return ChannelList(self.db, self.welcome)
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if not re.search(r'^\d+$', path):
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return resource.ErrorPage(http.BAD_REQUEST,
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"invalid channel id",
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"invalid channel id")
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channel_id = int(path)
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if not channel_id in self.channels:
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log.msg("spawning #%d" % channel_id)
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self.channels[channel_id] = Channel(channel_id, self, self.db,
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self.welcome)
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return self.channels[channel_id]
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def maybe_free_child(self, channel_id, side):
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self.db.execute("DELETE FROM `allocations`"
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" WHERE `channel_id`=? AND `side`=?",
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(channel_id, side))
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self.db.commit()
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remaining = self.db.execute("SELECT COUNT(*) FROM `allocations`"
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" WHERE `channel_id`=?",
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(channel_id,)).fetchone()[0]
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if remaining:
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return False
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self.free_child(channel_id)
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return True
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def free_child(self, channel_id):
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self.db.execute("DELETE FROM `allocations` WHERE `channel_id`=?",
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(channel_id,))
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self.db.execute("DELETE FROM `messages` WHERE `channel_id`=?",
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(channel_id,))
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self.db.commit()
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if channel_id in self.channels:
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self.channels.pop(channel_id)
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log.msg("freed+killed #%d, now have %d DB channels, %d live" %
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(channel_id, len(get_allocated(self.db)), len(self.channels)))
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def prune_old_channels(self):
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old = time.time() - self.PRUNE_AGE
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for channel_id in get_allocated(self.db):
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c = self.db.execute("SELECT `when` FROM `messages`"
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" WHERE `channel_id`=?"
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" ORDER BY `when` DESC LIMIT 1", (channel_id,))
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rows = c.fetchall()
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if not rows or (rows[0]["when"] < old):
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log.msg("expiring %d" % channel_id)
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self.free_child(channel_id)
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class TransitConnection(protocol.Protocol):
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def __init__(self):
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self.got_token = False
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self.token_buffer = b""
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self.sent_ok = False
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self.buddy = None
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self.total_sent = 0
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def dataReceived(self, data):
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if self.sent_ok:
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# TODO: connect as producer/consumer
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self.total_sent += len(data)
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self.buddy.transport.write(data)
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return
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if self.got_token: # but not yet sent_ok
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self.transport.write("impatient\n")
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print("transit impatience failure")
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return self.disconnect() # impatience yields failure
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# else this should be (part of) the token
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self.token_buffer += data
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buf = self.token_buffer
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wanted = len("please relay \n")+32*2
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if len(buf) < wanted-1 and "\n" in buf:
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self.transport.write("bad handshake\n")
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print("transit handshake early failure")
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return self.disconnect()
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if len(buf) < wanted:
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return
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if len(buf) > wanted:
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self.transport.write("impatient\n")
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print("transit impatience failure")
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return self.disconnect() # impatience yields failure
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mo = re.search(r"^please relay (\w{64})\n", buf, re.M)
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if not mo:
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self.transport.write("bad handshake\n")
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print("transit handshake failure")
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return self.disconnect() # incorrectness yields failure
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token = mo.group(1)
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self.got_token = True
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self.factory.connection_got_token(token, self)
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def buddy_connected(self, them):
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self.buddy = them
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self.transport.write(b"ok\n")
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self.sent_ok = True
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# TODO: connect as producer/consumer
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def buddy_disconnected(self):
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print("buddy_disconnected %r" % self)
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self.buddy = None
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self.transport.loseConnection()
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def connectionLost(self, reason):
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print("connectionLost %r %s" % (self, reason))
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if self.buddy:
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self.buddy.buddy_disconnected()
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self.factory.transitFinished(self, self.total_sent)
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def disconnect(self):
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self.transport.loseConnection()
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self.factory.transitFailed(self)
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class Transit(protocol.ServerFactory, service.MultiService):
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# I manage pairs of simultaneous connections to a secondary TCP port,
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# both forwarded to the other. Clients must begin each connection with
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# "please relay TOKEN\n". I will send "ok\n" when the matching connection
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# is established, or disconnect if no matching connection is made within
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# MAX_WAIT_TIME seconds. I will disconnect if you send data before the
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# "ok\n". All data you get after the "ok\n" will be from the other side.
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# You will not receive "ok\n" until the other side has also connected and
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# submitted a matching token. The token is the same for each side.
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# In addition, the connections will be dropped after MAXLENGTH bytes have
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# been sent by either side, or MAXTIME seconds have elapsed after the
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# matching connections were established. A future API will reveal these
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# limits to clients instead of causing mysterious spontaneous failures.
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# These relay connections are not half-closeable (unlike full TCP
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# connections, applications will not receive any data after half-closing
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# their outgoing side). Applications must negotiate shutdown with their
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# peer and not close the connection until all data has finished
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# transferring in both directions. Applications which only need to send
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# data in one direction can use close() as usual.
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MAX_WAIT_TIME = 30*SECONDS
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MAXLENGTH = 10*MB
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MAXTIME = 60*SECONDS
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protocol = TransitConnection
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def __init__(self):
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service.MultiService.__init__(self)
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self.pending_requests = {} # token -> TransitConnection
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self.active_connections = set() # TransitConnection
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def connection_got_token(self, token, p):
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if token in self.pending_requests:
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print("transit relay 2: %r" % token)
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buddy = self.pending_requests.pop(token)
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self.active_connections.add(p)
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self.active_connections.add(buddy)
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p.buddy_connected(buddy)
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buddy.buddy_connected(p)
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else:
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self.pending_requests[token] = p
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print("transit relay 1: %r" % token)
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# TODO: timer
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def transitFinished(self, p, total_sent):
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print("transitFinished (%dB) %r" % (total_sent, p))
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for token,tc in self.pending_requests.items():
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if tc is p:
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del self.pending_requests[token]
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break
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self.active_connections.discard(p)
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def transitFailed(self, p):
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print("transitFailed %r" % p)
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pass
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class Root(resource.Resource):
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# child_FOO is a nevow thing, not a twisted.web.resource thing
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def __init__(self):
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resource.Resource.__init__(self)
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self.putChild("", static.Data("Wormhole Relay\n", "text/plain"))
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class RelayServer(service.MultiService):
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def __init__(self, relayport, transitport, advertise_version):
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service.MultiService.__init__(self)
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self.db = get_db("relay.sqlite")
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welcome = {
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"current_version": __version__,
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# adding .motd will cause all clients to display the message,
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# then keep running normally
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#"motd": "Welcome to the public relay.\nPlease enjoy this service.",
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#
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# adding .error will cause all clients to fail, with this message
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#"error": "This server has been disabled, see URL for details.",
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}
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if advertise_version:
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welcome["current_version"] = advertise_version
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self.root = Root()
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site = server.Site(self.root)
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self.relayport_service = strports.service(relayport, site)
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self.relayport_service.setServiceParent(self)
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self.relay = Relay(self.db, welcome) # accessible from tests
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self.root.putChild("wormhole-relay", self.relay)
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t = internet.TimerService(2*HOUR, self.relay.prune_old_channels)
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t.setServiceParent(self)
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self.transit = Transit()
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self.transit.setServiceParent(self) # for the timer
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self.transport_service = strports.service(transitport, self.transit)
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self.transport_service.setServiceParent(self)
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