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# Copyright (C) 2008-2012 AG Projects. See LICENSE for details
"""Establish MSRP connection.
This module provides means to obtain a connected and bound MSRPTransport
instance. It uniformly handles 3 different configurations you may find your
client engaged in:
1. Calling endpoint, not using a relay (DirectConnector)
2. Answering endpoint, not using a relay (DirectAcceptor)
3. Endpoint using a relay (RelayConnection)
The answering endpoint may skip using the relay if sure that it's accessible
directly. The calling endpoint is unlikely to need the relay.
Once you have an instance of the right class, the procedure to establish the
connection is the same:
full_local_path = connector.prepare()
try:
... put full_local_path in SDP 'a:path' attribute
... get full_remote_path from remote's 'a:path: attribute
... (the order of the above steps is reversed if you're the
... answering party, but that does not affect connector's usage)
msrptransport = connector.complete(full_remote_path)
finally:
connector.cleanup()
To customize connection's parameters, create a new protocol.URI object and pass
it to prepare() function, e.g.
local_uri = protocol.URI(use_tls=False, port=5000)
connector.prepare(local_uri)
prepare() may update local_uri in place with the actual connection parameters
used (e.g. if you specified port=0). 'port' attribute of local_uri is currently
only respected by AcceptorDirect.
Note that, acceptors and connectors are one-use only. MSRPServer, on the contrary,
can be used multiple times.
"""
from __future__ import with_statement
import random
from twisted.internet.address import IPv4Address
from twisted.names.srvconnect import SRVConnector
from application.python import Null
from application.system import host
from eventlib.twistedutil.protocol import GreenClientCreator, SpawnFactory
from eventlib import coros
from eventlib.api import timeout, sleep
from eventlib.green.socket import gethostbyname
from gnutls.interfaces.twisted import TLSContext
from msrplib import protocol, MSRPError
from msrplib.transport import MSRPTransport, MSRPTransactionError, MSRPBadRequest, MSRPNoSuchSessionError
from msrplib.digest import process_www_authenticate
__all__ = ['MSRPRelaySettings',
'MSRPTimeout',
'MSRPConnectTimeout',
'MSRPRelayConnectTimeout',
'MSRPIncomingConnectTimeout',
'MSRPBindSessionTimeout',
'MSRPRelayAuthError',
'MSRPAuthTimeout',
'MSRPServer',
'DirectConnector',
'DirectAcceptor',
'RelayConnection']
class MSRPRelaySettings(protocol.ConnectInfo):
use_tls = True
def __init__(self, domain, username, password, host=None, port=None, use_tls=None, credentials=None):
protocol.ConnectInfo.__init__(self, host, use_tls=use_tls, port=port, credentials=credentials)
self.domain = domain
self.username = username
self.password = password
def __str__(self):
result = "MSRPRelay %s://%s" % (self.scheme, self.host or self.domain)
if self.port:
result += ':%s' % self.port
return result
def __repr__(self):
params = [self.domain, self.username, self.password, self.host, self.port]
if params[-1] is None:
del params[-1]
if params[-1] is None:
del params[-1]
return '%s(%s)' % (type(self).__name__, ', '.join(repr(x) for x in params))
@property
def uri_domain(self):
return protocol.URI(host=self.domain, port=self.port, use_tls=self.use_tls, session_id='')
class TimeoutMixin(object):
@classmethod
def timeout(cls, *throw_args):
if not throw_args:
throw_args = (cls, )
return timeout(cls.seconds, *throw_args)
class MSRPTimeout(MSRPError, TimeoutMixin):
seconds = 30
class MSRPConnectTimeout(MSRPTimeout):
pass
class MSRPRelayConnectTimeout(MSRPTimeout):
pass
class MSRPIncomingConnectTimeout(MSRPTimeout):
pass
class MSRPBindSessionTimeout(MSRPTimeout):
pass
class MSRPRelayAuthError(MSRPTransactionError):
pass
class MSRPAuthTimeout(MSRPTransactionError, TimeoutMixin):
code = 408
comment = 'No response to AUTH request'
seconds = 30
class MSRPSRVConnector(SRVConnector):
def pickServer(self):
assert self.servers is not None
assert self.orderedServers is not None
if not self.servers and not self.orderedServers:
# no SRV record, fall back..
return self.domain, 2855
return SRVConnector.pickServer(self)
class ConnectBase(object):
SRVConnectorClass = MSRPSRVConnector
def __init__(self, logger=Null, use_sessmatch=False):
self.logger = logger
self.use_sessmatch = use_sessmatch
self.local_uri = None
def _connect(self, local_uri, remote_uri):
self.logger.info('Connecting to %s', remote_uri)
creator = GreenClientCreator(gtransport_class=MSRPTransport, local_uri=local_uri, logger=self.logger, use_sessmatch=self.use_sessmatch)
if remote_uri.host:
if remote_uri.use_tls:
msrp = creator.connectTLS(remote_uri.host, remote_uri.port or 2855, TLSContext(local_uri.credentials))
else:
msrp = creator.connectTCP(remote_uri.host, remote_uri.port or 2855)
else:
if not remote_uri.domain:
raise ValueError("remote_uri must have either 'host' or 'domain'")
if remote_uri.use_tls:
connectFuncName = 'connectTLS'
connectFuncArgs = (TLSContext(local_uri.credentials),)
else:
connectFuncName = 'connectTCP'
connectFuncArgs = ()
msrp = creator.connectSRV(remote_uri.scheme, remote_uri.domain,
connectFuncName=connectFuncName,
connectFuncArgs=connectFuncArgs,
ConnectorClass=self.SRVConnectorClass)
remote_address = msrp.getPeer()
self.logger.info('Connected to %s:%s', remote_address.host, remote_address.port)
return msrp
def _listen(self, local_uri, factory):
from twisted.internet import reactor
if local_uri.use_tls:
port = reactor.listenTLS(local_uri.port or 0, factory, TLSContext(local_uri.credentials), interface=local_uri.host)
else:
port = reactor.listenTCP(local_uri.port or 0, factory, interface=local_uri.host)
local_address = port.getHost()
local_uri.port = local_address.port
self.logger.info('Listening for incoming %s connections on %s:%s', local_uri.scheme.upper(), local_address.host, local_address.port)
return port
def cleanup(self, wait=True):
pass
class DirectConnector(ConnectBase):
def __init__(self, logger=Null, use_sessmatch=False):
ConnectBase.__init__(self, logger, use_sessmatch)
self.host_ip = host.default_ip
def __repr__(self):
return '<%s at %s local_uri=%s>' % (type(self).__name__, hex(id(self)), getattr(self, 'local_uri', '(none)'))
def prepare(self, local_uri=None):
local_uri = local_uri or protocol.URI(port=0)
local_uri.port = local_uri.port or 2855
self.local_uri = local_uri
return [local_uri]
def getHost(self):
return IPv4Address('TCP', self.host_ip, 0)
def complete(self, full_remote_path):
with MSRPConnectTimeout.timeout():
msrp = self._connect(self.local_uri, full_remote_path[0])
# can't do the following, because local_uri was already used in the INVITE
#msrp.local_uri.port = msrp.getHost().port
try:
with MSRPBindSessionTimeout.timeout():
msrp.bind(full_remote_path)
except:
msrp.loseConnection(wait=False)
raise
return msrp
class DirectAcceptor(ConnectBase):
def __init__(self, logger=Null, use_sessmatch=False):
ConnectBase.__init__(self, logger, use_sessmatch)
self.listening_port = None
self.transport_event = None
def __repr__(self):
return '<%s at %s local_uri=%s listening_port=%s>' % (type(self).__name__, hex(id(self)), self.local_uri, self.listening_port)
def prepare(self, local_uri=None):
"""Start listening for an incoming MSRP connection using port and
use_tls from local_uri if provided.
Return full local path, suitable to put in SDP a:path attribute.
Note, that `local_uri' may be updated in place.
"""
local_uri = local_uri or protocol.URI(port=0)
self.transport_event = coros.event()
local_uri.host = gethostbyname(local_uri.host)
factory = SpawnFactory(self.transport_event, MSRPTransport, local_uri, logger=self.logger, use_sessmatch=self.use_sessmatch)
self.listening_port = self._listen(local_uri, factory)
self.local_uri = local_uri
return [local_uri]
def getHost(self):
return self.listening_port.getHost()
def complete(self, full_remote_path):
"""Accept an incoming MSRP connection and bind it.
Return MSRPTransport instance.
"""
try:
with MSRPIncomingConnectTimeout.timeout():
msrp = self.transport_event.wait()
remote_address = msrp.getPeer()
self.logger.info('Incoming %s connection from %s:%s', self.local_uri.scheme.upper(), remote_address.host, remote_address.port)
finally:
self.cleanup()
try:
with MSRPBindSessionTimeout.timeout():
msrp.accept_binding(full_remote_path)
except:
msrp.loseConnection(wait=False)
raise
return msrp
def cleanup(self, wait=True):
if self.listening_port is not None:
self.listening_port.stopListening()
self.listening_port = None
self.transport_event = None
self.local_uri = None
def _deliver_chunk(msrp, chunk):
msrp.write_chunk(chunk)
with MSRPAuthTimeout.timeout():
response = msrp.read_chunk()
if response.method is not None:
raise MSRPBadRequest
if response.transaction_id!=chunk.transaction_id:
raise MSRPBadRequest
return response
class RelayConnection(ConnectBase):
def __init__(self, relay, mode, logger=Null, use_sessmatch=False):
if mode not in ('active', 'passive'):
raise ValueError("RelayConnection mode should be one of 'active' or 'passive'")
ConnectBase.__init__(self, logger, use_sessmatch)
self.mode = mode
self.relay = relay
self.msrp = None
def __repr__(self):
return '<%s at %s relay=%r msrp=%s>' % (type(self).__name__, hex(id(self)), self.relay, self.msrp)
def _relay_connect(self):
try:
msrp = self._connect(self.local_uri, self.relay)
except Exception:
self.logger.info('Could not connect to relay %s', self.relay)
raise
local_address = msrp.getHost()
remote_address = msrp.getPeer()
try:
self.local_uri.port = local_address.port
msrpdata = protocol.MSRPData(method="AUTH", transaction_id='%x' % random.getrandbits(64))
msrpdata.add_header(protocol.ToPathHeader([self.relay.uri_domain]))
msrpdata.add_header(protocol.FromPathHeader([self.local_uri]))
response = _deliver_chunk(msrp, msrpdata)
if response.code == 401:
www_authenticate = response.headers["WWW-Authenticate"]
auth, rsp_auth = process_www_authenticate(self.relay.username, self.relay.password, "AUTH",
str(self.relay.uri_domain), **www_authenticate.decoded)
msrpdata.transaction_id = '%x' % random.getrandbits(64)
msrpdata.add_header(protocol.AuthorizationHeader(auth))
response = _deliver_chunk(msrp, msrpdata)
if response.code != 200:
raise MSRPRelayAuthError(comment=response.comment, code=response.code)
msrp.set_local_path(list(response.headers["Use-Path"].decoded))
self.logger.info('Reserved session at relay %s:%s', remote_address.host, remote_address.port)
except:
self.logger.info('Could not reserve session at relay %s:%s', remote_address.host, remote_address.port)
msrp.loseConnection(wait=False)
raise
return msrp
def _relay_connect_timeout(self):
with MSRPRelayConnectTimeout.timeout():
return self._relay_connect()
def prepare(self, local_uri=None):
self.local_uri = local_uri or protocol.URI(port=0)
self.msrp = self._relay_connect_timeout()
return self.msrp.full_local_path
def getHost(self):
return self.msrp.getHost()
def cleanup(self, wait=True):
if self.msrp is not None:
self.msrp.loseConnection(wait=wait)
self.msrp = None
def complete(self, full_remote_path):
try:
with MSRPBindSessionTimeout.timeout():
if self.mode == 'active':
self.msrp.bind(full_remote_path)
else:
self.msrp.accept_binding(full_remote_path)
return self.msrp
except:
self.msrp.loseConnection(wait=False)
raise
finally:
self.msrp = None
class Notifier(coros.event):
def wait(self):
if self.ready():
self.reset()
return coros.event.wait(self)
def send(self, value=None, exc=None):
if self.ready():
self.reset()
return coros.event.send(self, value, exc=exc)
class MSRPServer(ConnectBase):
"""Manage listening sockets. Bind incoming requests.
MSRPServer solves the problem with AcceptorDirect: concurrent using of 2
or more AcceptorDirect instances on the same non-zero port is not possible.
If you initialize() those instances, one after another, one will listen on
the socket and another will get BindError.
MSRPServer avoids the problem by sharing the listening socket between multiple connections.
It has slightly different interface from AcceptorDirect, so it cannot be considered a drop-in
replacement.
"""
CLOSE_TIMEOUT = MSRPBindSessionTimeout.seconds * 2
def __init__(self, logger):
ConnectBase.__init__(self, logger)
self.ports = {} # maps interface -> port -> (use_tls, listening Port)
self.queue = coros.queue()
self.expected_local_uris = {} # maps local_uri -> Logger instance
self.expected_remote_paths = {} # maps full_remote_path -> event
self.new_full_remote_path_notifier = Notifier()
self.factory = SpawnFactory(self._incoming_handler, MSRPTransport, local_uri=None, logger=self.logger)
def prepare(self, local_uri=None, logger=None):
"""Start a listening port specified by local_uri if there isn't one on that port/interface already.
Add `local_uri' to the list of expected URIs, so that incoming connections featuring this URI won't be rejected.
If `logger' is provided use it for this connection instead of the default one.
"""
local_uri = local_uri or protocol.URI(port=2855)
need_listen = True
if local_uri.port:
use_tls, listening_port = self.ports.get(local_uri.host, {}).get(local_uri.port, (None, None))
if listening_port is not None:
if use_tls==local_uri.use_tls:
need_listen = False
else:
listening_port.stopListening()
sleep(0) # make the reactor really stop listening, so that the next listen() call won't fail
self.ports.pop(local_uri.host, {}).pop(local_uri.port, None)
else:
# caller does not care about port number
for (use_tls, port) in self.ports[local_uri.host]:
if local_uri.use_tls==use_tls:
local_uri.port = port.getHost().port
need_listen = False
if need_listen:
port = self._listen(local_uri, self.factory)
self.ports.setdefault(local_uri.host, {})[local_uri.port] = (local_uri.use_tls, port)
self.expected_local_uris[local_uri] = logger
self.local_uri = local_uri
return [local_uri]
def _incoming_handler(self, msrp):
peer = msrp.getPeer()
self.logger.info('Incoming connection from %s:%s', peer.host, peer.port)
with MSRPBindSessionTimeout.timeout():
chunk = msrp.read_chunk()
to_path = chunk.to_path
if len(to_path) != 1:
msrp.write_response(chunk, 400, 'Invalid To-Path', wait=False)
msrp.loseConnection(wait=False)
return
to_path = to_path[0]
if to_path in self.expected_local_uris:
logger = self.expected_local_uris.pop(to_path)
if logger is not None:
msrp.logger = logger
msrp.local_uri = to_path
else:
msrp.write_response(chunk, 481, 'Unknown To-Path', wait=False)
msrp.loseConnection(wait=False)
return
from_path = tuple(chunk.from_path)
# at this point, must wait for complete() function to be called which will
# provide an event for this full_remote_path
while True:
event = self.expected_remote_paths.pop(from_path, None)
if event is not None:
break
self.new_full_remote_path_notifier.wait()
if event is not None:
msrp._set_full_remote_path(list(from_path))
error = msrp.check_incoming_SEND_chunk(chunk)
else:
error = MSRPNoSuchSessionError
if error is None:
msrp.write_response(chunk, 200, 'OK')
if 'Content-Type' in chunk.headers or chunk.size>0:
# chunk must be made available to read_chunk() again because it has payload
raise NotImplementedError
if event is not None:
event.send(msrp)
else:
msrp.write_response(chunk, error.code, error.comment)
def complete(self, full_remote_path):
"""Wait until one of the incoming connections binds using provided full_remote_path.
Return connected and bound MSRPTransport instance.
If no such binding was made within MSRPBindSessionTimeout.seconds, raise MSRPBindSessionTimeout.
"""
full_remote_path = tuple(full_remote_path)
event = coros.event()
self.expected_remote_paths[full_remote_path] = event
try:
self.new_full_remote_path_notifier.send()
with MSRPBindSessionTimeout.timeout():
return event.wait()
finally:
self.expected_remote_paths.pop(full_remote_path, None)
def cleanup(self, local_uri):
"""Remove `local_uri' from the list of expected URIs"""
self.expected_local_uris.pop(local_uri, None)
def stopListening(self):
"""Close all the sockets that MSRPServer is listening on"""
for interface, rest in self.ports.iteritems():
for port, (use_tls, listening_port) in rest:
listening_port.stopListening()
self.ports = {}
def close(self):
"""Stop listening. Wait for the spawned greenlets to finish"""
self.stopListening()
with timeout(self.CLOSE_TIMEOUT, None):
self.factory.waitall()

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