magic-wormhole/src/wormhole/server/transit_server.py

329 lines
13 KiB
Python

from __future__ import print_function, unicode_literals
import re, time, collections
from twisted.python import log
from twisted.internet import protocol
from twisted.application import service
SECONDS = 1.0
MINUTE = 60*SECONDS
HOUR = 60*MINUTE
DAY = 24*HOUR
MB = 1000*1000
def round_to(size, coarseness):
return int(coarseness*(1+int((size-1)/coarseness)))
def blur_size(size):
if size == 0:
return 0
if size < 1e6:
return round_to(size, 10e3)
if size < 1e9:
return round_to(size, 1e6)
return round_to(size, 100e6)
class TransitConnection(protocol.Protocol):
def __init__(self):
self._got_token = False
self._got_side = False
self._token_buffer = b""
self._sent_ok = False
self._buddy = None
self._had_buddy = False
self._total_sent = 0
def describeToken(self):
d = "-"
if self._got_token:
d = self._got_token[:16].decode("ascii")
if self._got_side:
d += "-" + self._got_side.decode("ascii")
else:
d += "-<unsided>"
return d
def connectionMade(self):
self._started = time.time()
self._log_requests = self.factory._log_requests
def dataReceived(self, data):
if self._sent_ok:
# We are an IPushProducer to our buddy's IConsumer, so they'll
# throttle us (by calling pauseProducing()) when their outbound
# buffer is full (e.g. when their downstream pipe is full). In
# practice, this buffers about 10MB per connection, after which
# point the sender will only transmit data as fast as the
# receiver can handle it.
self._total_sent += len(data)
self._buddy.transport.write(data)
return
if self._got_token: # but not yet sent_ok
self.transport.write(b"impatient\n")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect() # impatience yields failure
# else this should be (part of) the token
self._token_buffer += data
buf = self._token_buffer
# old: "please relay {64}\n"
# new: "please relay {64} for side {16}\n"
(old, handshake_len, token) = self._check_old_handshake(buf)
assert old in ("yes", "waiting", "no")
if old == "yes":
# remember they aren't supposed to send anything past their
# handshake until we've said go
if len(buf) > handshake_len:
self.transport.write(b"impatient\n")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect() # impatience yields failure
return self._got_handshake(token, None)
(new, handshake_len, token, side) = self._check_new_handshake(buf)
assert new in ("yes", "waiting", "no")
if new == "yes":
if len(buf) > handshake_len:
self.transport.write(b"impatient\n")
if self._log_requests:
log.msg("transit impatience failure")
return self.disconnect() # impatience yields failure
return self._got_handshake(token, side)
if (old == "no" and new == "no"):
self.transport.write(b"bad handshake\n")
if self._log_requests:
log.msg("transit handshake failure")
return self.disconnect() # incorrectness yields failure
# else we'll keep waiting
def _check_old_handshake(self, buf):
# old: "please relay {64}\n"
# return ("yes", handshake, token) if buf contains an old-style handshake
# return ("waiting", None, None) if it might eventually contain one
# return ("no", None, None) if it could never contain one
wanted = len("please relay \n")+32*2
if len(buf) < wanted-1 and b"\n" in buf:
return ("no", None, None)
if len(buf) < wanted:
return ("waiting", None, None)
mo = re.search(br"^please relay (\w{64})\n", buf, re.M)
if mo:
token = mo.group(1)
return ("yes", wanted, token)
return ("no", None, None)
def _check_new_handshake(self, buf):
# new: "please relay {64} for side {16}\n"
wanted = len("please relay for side \n")+32*2+8*2
if len(buf) < wanted-1 and b"\n" in buf:
return ("no", None, None, None)
if len(buf) < wanted:
return ("waiting", None, None, None)
mo = re.search(br"^please relay (\w{64}) for side (\w{16})\n", buf, re.M)
if mo:
token = mo.group(1)
side = mo.group(2)
return ("yes", wanted, token, side)
return ("no", None, None, None)
def _got_handshake(self, token, side):
self._got_token = token
self._got_side = side
self.factory.connection_got_token(token, side, self)
def buddy_connected(self, them):
self._buddy = them
self._had_buddy = True
self.transport.write(b"ok\n")
self._sent_ok = True
# Connect the two as a producer/consumer pair. We use streaming=True,
# so this expects the IPushProducer interface, and uses
# pauseProducing() to throttle, and resumeProducing() to unthrottle.
self._buddy.transport.registerProducer(self.transport, True)
# The Transit object calls buddy_connected() on both protocols, so
# there will be two producer/consumer pairs.
def buddy_disconnected(self):
if self._log_requests:
log.msg("buddy_disconnected %s" % self.describeToken())
self._buddy = None
self.transport.loseConnection()
def connectionLost(self, reason):
if self._buddy:
self._buddy.buddy_disconnected()
self.factory.transitFinished(self, self._got_token, self._got_side,
self.describeToken())
# Record usage. There are four cases:
# * 1: we connected, never had a buddy
# * 2: we connected first, we disconnect before the buddy
# * 3: we connected first, buddy disconnects first
# * 4: buddy connected first, we disconnect before buddy
# * 5: buddy connected first, buddy disconnects first
# whoever disconnects first gets to write the usage record (1,2,4)
finished = time.time()
if not self._had_buddy: # 1
total_time = finished - self._started
self.factory.recordUsage(self._started, "lonely", 0,
total_time, None)
if self._had_buddy and self._buddy: # 2,4
total_bytes = self._total_sent + self._buddy._total_sent
starts = [self._started, self._buddy._started]
total_time = finished - min(starts)
waiting_time = max(starts) - min(starts)
self.factory.recordUsage(self._started, "happy", total_bytes,
total_time, waiting_time)
def disconnect(self):
self.transport.loseConnection()
self.factory.transitFailed(self)
finished = time.time()
total_time = finished - self._started
self.factory.recordUsage(self._started, "errory", 0,
total_time, None)
class Transit(protocol.ServerFactory, service.MultiService):
# I manage pairs of simultaneous connections to a secondary TCP port,
# both forwarded to the other. Clients must begin each connection with
# "please relay TOKEN for SIDE\n" (or a legacy form without the "for
# SIDE"). Two connections match if they use the same TOKEN and have
# different SIDEs (the redundant connections are dropped when a match is
# made). Legacy connections match any with the same TOKEN, ignoring SIDE
# (so two legacy connections will match each other).
# I will send "ok\n" when the matching connection is established, or
# disconnect if no matching connection is made within MAX_WAIT_TIME
# seconds. I will disconnect if you send data before the "ok\n". All data
# you get after the "ok\n" will be from the other side. You will not
# receive "ok\n" until the other side has also connected and submitted a
# matching token (and differing SIDE).
# In addition, the connections will be dropped after MAXLENGTH bytes have
# been sent by either side, or MAXTIME seconds have elapsed after the
# matching connections were established. A future API will reveal these
# limits to clients instead of causing mysterious spontaneous failures.
# These relay connections are not half-closeable (unlike full TCP
# connections, applications will not receive any data after half-closing
# their outgoing side). Applications must negotiate shutdown with their
# peer and not close the connection until all data has finished
# transferring in both directions. Applications which only need to send
# data in one direction can use close() as usual.
MAX_WAIT_TIME = 30*SECONDS
MAXLENGTH = 10*MB
MAXTIME = 60*SECONDS
protocol = TransitConnection
def __init__(self, db, blur_usage):
service.MultiService.__init__(self)
self._db = db
self._blur_usage = blur_usage
self._log_requests = blur_usage is None
self._pending_requests = {} # token -> set((side, TransitConnection))
self._active_connections = set() # TransitConnection
self._counts = collections.defaultdict(int)
self._count_bytes = 0
def connection_got_token(self, token, new_side, new_tc):
if token not in self._pending_requests:
self._pending_requests[token] = set()
potentials = self._pending_requests[token]
for old in potentials:
(old_side, old_tc) = old
if ((old_side is None)
or (new_side is None)
or (old_side != new_side)):
# we found a match
if self._log_requests:
log.msg("transit relay 2: %s" % new_tc.describeToken())
# drop and stop tracking the rest
potentials.remove(old)
for (_, leftover_tc) in potentials:
leftover_tc.disconnect() # TODO: not "errory"?
self._pending_requests.pop(token)
# glue the two ends together
self._active_connections.add(new_tc)
self._active_connections.add(old_tc)
new_tc.buddy_connected(old_tc)
old_tc.buddy_connected(new_tc)
return
if self._log_requests:
log.msg("transit relay 1: %s" % new_tc.describeToken())
potentials.add((new_side, new_tc))
# TODO: timer
def recordUsage(self, started, result, total_bytes,
total_time, waiting_time):
if self._log_requests:
log.msg("Transit.recordUsage (%dB)" % total_bytes)
if self._blur_usage:
started = self._blur_usage * (started // self._blur_usage)
total_bytes = blur_size(total_bytes)
self._db.execute("INSERT INTO `transit_usage`"
" (`started`, `total_time`, `waiting_time`,"
" `total_bytes`, `result`)"
" VALUES (?,?,?, ?,?)",
(started, total_time, waiting_time,
total_bytes, result))
self._db.commit()
self._counts[result] += 1
self._count_bytes += total_bytes
def transitFinished(self, tc, token, side, description):
if token in self._pending_requests:
side_tc = (side, tc)
if side_tc in self._pending_requests[token]:
self._pending_requests[token].remove(side_tc)
if not self._pending_requests[token]: # set is now empty
del self._pending_requests[token]
if self._log_requests:
log.msg("transitFinished %s" % (description,))
self._active_connections.discard(tc)
def transitFailed(self, p):
if self._log_requests:
log.msg("transitFailed %r" % p)
pass
def get_stats(self):
stats = {}
def q(query, values=()):
row = self._db.execute(query, values).fetchone()
return list(row.values())[0]
# current status: expected to be zero most of the time
c = stats["active"] = {}
c["connected"] = len(self._active_connections) / 2
c["waiting"] = len(self._pending_requests)
# usage since last reboot
rb = stats["since_reboot"] = {}
rb["bytes"] = self._count_bytes
rb["total"] = sum(self._counts.values(), 0)
rbm = rb["moods"] = {}
for result, count in self._counts.items():
rbm[result] = count
# historical usage (all-time)
u = stats["all_time"] = {}
u["total"] = q("SELECT COUNT() FROM `transit_usage`")
u["bytes"] = q("SELECT SUM(`total_bytes`) FROM `transit_usage`") or 0
um = u["moods"] = {}
um["happy"] = q("SELECT COUNT() FROM `transit_usage`"
" WHERE `result`='happy'")
um["lonely"] = q("SELECT COUNT() FROM `transit_usage`"
" WHERE `result`='lonely'")
um["errory"] = q("SELECT COUNT() FROM `transit_usage`"
" WHERE `result`='errory'")
return stats