--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sat/plugins/plugin_xep_0260.py	Mon Apr 02 19:44:50 2018 +0200
@@ -0,0 +1,459 @@
+#!/usr/bin/env python2
+# -*- coding: utf-8 -*-
+
+# SAT plugin for Jingle (XEP-0260)
+# Copyright (C) 2009-2018 Jérôme Poisson (goffi@goffi.org)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from sat.core.i18n import _
+from sat.core.constants import Const as C
+from sat.core.log import getLogger
+log = getLogger(__name__)
+from sat.core import exceptions
+from wokkel import disco, iwokkel
+from zope.interface import implements
+from twisted.words.xish import domish
+from twisted.words.protocols.jabber import jid
+from twisted.internet import defer
+import uuid
+
+try:
+    from twisted.words.protocols.xmlstream import XMPPHandler
+except ImportError:
+    from wokkel.subprotocols import XMPPHandler
+
+
+NS_JINGLE_S5B = 'urn:xmpp:jingle:transports:s5b:1'
+
+PLUGIN_INFO = {
+    C.PI_NAME: "Jingle SOCKS5 Bytestreams",
+    C.PI_IMPORT_NAME: "XEP-0260",
+    C.PI_TYPE: "XEP",
+    C.PI_MODES: C.PLUG_MODE_BOTH,
+    C.PI_PROTOCOLS: ["XEP-0260"],
+    C.PI_DEPENDENCIES: ["XEP-0166", "XEP-0065"],
+    C.PI_RECOMMENDATIONS: ["XEP-0261"], # needed for fallback
+    C.PI_MAIN: "XEP_0260",
+    C.PI_HANDLER: "yes",
+    C.PI_DESCRIPTION: _("""Implementation of Jingle SOCKS5 Bytestreams""")
+}
+
+
+class ProxyError(Exception):
+
+    def __str__(self):
+        return "an error happened while trying to use the proxy"
+
+
+class XEP_0260(object):
+    # TODO: udp handling
+
+    def __init__(self, host):
+        log.info(_("plugin Jingle SOCKS5 Bytestreams"))
+        self.host = host
+        self._j = host.plugins["XEP-0166"] # shortcut to access jingle
+        self._s5b = host.plugins["XEP-0065"] # and socks5 bytestream
+        try:
+            self._jingle_ibb = host.plugins["XEP-0261"]
+        except KeyError:
+            self._jingle_ibb = None
+        self._j.registerTransport(NS_JINGLE_S5B, self._j.TRANSPORT_STREAMING, self, 100)
+
+    def getHandler(self, client):
+        return XEP_0260_handler()
+
+    def _parseCandidates(self, transport_elt):
+        """Parse <candidate> elements
+
+        @param transport_elt(domish.Element): parent <transport> element
+        @return (list[plugin_xep_0065.Candidate): list of parsed candidates
+        """
+        candidates = []
+        for candidate_elt in transport_elt.elements(NS_JINGLE_S5B, 'candidate'):
+            try:
+                cid = candidate_elt['cid']
+                host = candidate_elt['host']
+                jid_= jid.JID(candidate_elt['jid'])
+                port = int(candidate_elt.getAttribute('port', 1080))
+                priority = int(candidate_elt['priority'])
+                type_ = candidate_elt.getAttribute('type', self._s5b.TYPE_DIRECT)
+            except (KeyError, ValueError):
+                raise exceptions.DataError()
+            candidate = self._s5b.Candidate(host, port, type_, priority, jid_, cid)
+            candidates.append(candidate)
+            # self._s5b.registerCandidate(candidate)
+        return candidates
+
+    def _buildCandidates(self, session, candidates, sid, session_hash, client, mode=None):
+        """Build <transport> element with candidates
+
+        @param session(dict): jingle session data
+        @param candidates(iterator[plugin_xep_0065.Candidate]): iterator of candidates to add
+        @param sid(unicode): transport stream id
+        @param client: %(doc_client)s
+        @param mode(str, None): 'tcp' or 'udp', or None to have no attribute
+        @return (domish.Element): parent <transport> element where <candidate> elements must be added
+        """
+        proxy = next((candidate for candidate in candidates if candidate.type == self._s5b.TYPE_PROXY), None)
+        transport_elt = domish.Element((NS_JINGLE_S5B, "transport"))
+        transport_elt['sid'] = sid
+        if proxy is not None:
+            transport_elt['dstaddr'] = session_hash
+        if mode is not None:
+            transport_elt['mode'] = 'tcp' # XXX: we only manage tcp for now
+
+        for candidate in candidates:
+            log.debug(u"Adding candidate: {}".format(candidate))
+            candidate_elt = transport_elt.addElement('candidate', NS_JINGLE_S5B)
+            if candidate.id is None:
+                candidate.id = unicode(uuid.uuid4())
+            candidate_elt['cid'] = candidate.id
+            candidate_elt['host'] = candidate.host
+            candidate_elt['jid'] = candidate.jid.full()
+            candidate_elt['port'] = unicode(candidate.port)
+            candidate_elt['priority'] = unicode(candidate.priority)
+            candidate_elt['type'] = candidate.type
+        return transport_elt
+
+    @defer.inlineCallbacks
+    def jingleSessionInit(self, client, session, content_name):
+        content_data = session['contents'][content_name]
+        transport_data = content_data['transport_data']
+        sid = transport_data['sid'] = unicode(uuid.uuid4())
+        session_hash = transport_data['session_hash'] = self._s5b.getSessionHash(client.jid, session['peer_jid'], sid)
+        transport_data['peer_session_hash'] = self._s5b.getSessionHash(session['peer_jid'], client.jid, sid) # requester and target are inversed for peer candidates
+        transport_data['stream_d'] = self._s5b.registerHash(client, session_hash, None)
+        candidates = transport_data['candidates'] = yield self._s5b.getCandidates(client)
+        mode = 'tcp' # XXX: we only manage tcp for now
+        transport_elt = self._buildCandidates(session, candidates, sid, session_hash, client, mode)
+
+        defer.returnValue(transport_elt)
+
+    def _proxyActivatedCb(self, iq_result_elt, client, candidate, session, content_name):
+        """Called when activation confirmation has been received from proxy
+
+        cf XEP-0260 § 2.4
+        """
+        # now that the proxy is activated, we have to inform other peer
+        iq_elt, transport_elt = self._j.buildAction(client, self._j.A_TRANSPORT_INFO, session, content_name)
+        activated_elt = transport_elt.addElement('activated')
+        activated_elt['cid'] = candidate.id
+        iq_elt.send()
+
+    def _proxyActivatedEb(self, stanza_error, client, candidate, session, content_name):
+        """Called when activation error has been received from proxy
+
+        cf XEP-0260 § 2.4
+        """
+        # TODO: fallback to IBB
+        # now that the proxy is activated, we have to inform other peer
+        iq_elt, transport_elt = self._j.buildAction(client, self._j.A_TRANSPORT_INFO, session, content_name)
+        transport_elt.addElement('proxy-error')
+        iq_elt.send()
+        log.warning(u"Can't activate proxy, we need to fallback to IBB: {reason}"
+            .format(reason = stanza_error.value.condition))
+        self.doFallback(session, content_name, client)
+
+    def _foundPeerCandidate(self, candidate, session, transport_data, content_name, client):
+        """Called when the best candidate from other peer is found
+
+        @param candidate(XEP_0065.Candidate, None): selected candidate,
+            or None if no candidate is accessible
+        @param session(dict):  session data
+        @param transport_data(dict): transport data
+        @param content_name(unicode): name of the current content
+        @param client(unicode): %(doc_client)s
+        """
+
+        transport_data['best_candidate'] = candidate
+        # we need to disconnect all non selected candidates before removing them
+        for c in transport_data['peer_candidates']:
+            if c is None or c is candidate:
+                continue
+            c.discard()
+        del transport_data['peer_candidates']
+        iq_elt, transport_elt = self._j.buildAction(client, self._j.A_TRANSPORT_INFO, session, content_name)
+        if candidate is None:
+            log.warning(u"Can't connect to any peer candidate")
+            candidate_elt = transport_elt.addElement('candidate-error')
+        else:
+            log.info(u"Found best peer candidate: {}".format(unicode(candidate)))
+            candidate_elt = transport_elt.addElement('candidate-used')
+            candidate_elt['cid'] = candidate.id
+        iq_elt.send() # TODO: check result stanza
+        self._checkCandidates(session, content_name, transport_data, client)
+
+    def _checkCandidates(self, session, content_name, transport_data, client):
+        """Called when a candidate has been choosed
+
+        if we have both candidates, we select one, or fallback to an other transport
+        @param session(dict):  session data
+        @param content_name(unicode): name of the current content
+        @param transport_data(dict): transport data
+        @param client(unicode): %(doc_client)s
+        """
+        content_data = session['contents'][content_name]
+        try:
+            best_candidate = transport_data['best_candidate']
+        except KeyError:
+            # we have not our best candidate yet
+            return
+        try:
+            peer_best_candidate = transport_data['peer_best_candidate']
+        except KeyError:
+            # we have not peer best candidate yet
+            return
+
+        # at this point we have both candidates, it's time to choose one
+        if best_candidate is None or peer_best_candidate is None:
+            choosed_candidate = best_candidate or peer_best_candidate
+        else:
+            if best_candidate.priority == peer_best_candidate.priority:
+                # same priority, we choose initiator one according to XEP-0260 §2.4 #4
+                log.debug(u"Candidates have same priority, we select the one choosed by initiator")
+                if session['initiator'] == client.jid:
+                    choosed_candidate = best_candidate
+                else:
+                    choosed_candidate = peer_best_candidate
+            else:
+                choosed_candidate = max(best_candidate, peer_best_candidate, key=lambda c:c.priority)
+
+        if choosed_candidate is None:
+            log.warning(u"Socks5 negociation failed, we need to fallback to IBB")
+            self.doFallback(session, content_name, client)
+        else:
+            if choosed_candidate == peer_best_candidate:
+                # peer_best_candidate was choosed from the candidates we have sent
+                # so our_candidate is true if choosed_candidate is peer_best_candidate
+                our_candidate = True
+                # than also mean that best_candidate must be discarded !
+                try:
+                    best_candidate.discard()
+                except AttributeError: # but it can be None
+                    pass
+            else:
+                our_candidate = False
+
+            log.info(u"Socks5 negociation successful, {who} candidate will be used: {candidate}".format(
+                who = u'our' if our_candidate else u'other peer',
+                candidate = choosed_candidate))
+            del transport_data['best_candidate']
+            del transport_data['peer_best_candidate']
+
+            if choosed_candidate.type == self._s5b.TYPE_PROXY:
+                # the stream transfer need to wait for proxy activation
+                # (see XEP-0260 § 2.4)
+                if our_candidate:
+                    d = self._s5b.connectCandidate(client, choosed_candidate, transport_data['session_hash'])
+                    d.addCallback(lambda dummy: choosed_candidate.activate(transport_data['sid'], session['peer_jid'], client))
+                    args = [client, choosed_candidate, session, content_name]
+                    d.addCallbacks(self._proxyActivatedCb, self._proxyActivatedEb, args, None, args)
+                else:
+                    # this Deferred will be called when we'll receive activation confirmation from other peer
+                    d = transport_data['activation_d'] = defer.Deferred()
+            else:
+                d = defer.succeed(None)
+
+            if content_data['senders'] == session['role']:
+                # we can now start the stream transfer (or start it after proxy activation)
+                d.addCallback(lambda dummy: choosed_candidate.startTransfer(transport_data['session_hash']))
+                d.addErrback(self._startEb, session, content_name, client)
+
+    def _startEb(self, fail, session, content_name, client):
+        """Called when it's not possible to start the transfer
+
+        Will try to fallback to IBB
+        """
+        try:
+            reason = unicode(fail.value)
+        except AttributeError:
+            reason = unicode(fail)
+        log.warning(u"Cant start transfert, we'll try fallback method: {}".format(reason))
+        self.doFallback(session, content_name, client)
+
+    def _candidateInfo(self, candidate_elt, session, content_name, transport_data, client):
+        """Called when best candidate has been received from peer (or if none is working)
+
+        @param candidate_elt(domish.Element): candidate-used or candidate-error element
+            (see XEP-0260 §2.3)
+        @param session(dict):  session data
+        @param content_name(unicode): name of the current content
+        @param transport_data(dict): transport data
+        @param client(unicode): %(doc_client)s
+        """
+        if candidate_elt.name == 'candidate-error':
+            # candidate-error, no candidate worked
+            transport_data['peer_best_candidate'] = None
+        else:
+            # candidate-used, one candidate was choosed
+            try:
+                cid = candidate_elt.attributes['cid']
+            except KeyError:
+                log.warning(u"No cid found in <candidate-used>")
+                raise exceptions.DataError
+            try:
+                candidate = (c for c in transport_data['candidates'] if c.id == cid).next()
+            except StopIteration:
+                log.warning(u"Given cid doesn't correspond to any known candidate !")
+                raise exceptions.DataError # TODO: send an error to other peer, and use better exception
+            except KeyError:
+                # a transport-info can also be intentionaly sent too early by other peer
+                # but there is little probability
+                log.error(u'"candidates" key doesn\'t exists in transport_data, it should at this point')
+                raise exceptions.InternalError
+            # at this point we have the candidate choosed by other peer
+            transport_data['peer_best_candidate'] = candidate
+            log.info(u"Other peer best candidate: {}".format(candidate))
+
+        del transport_data['candidates']
+        self._checkCandidates(session, content_name, transport_data, client)
+
+    def _proxyActivationInfo(self, proxy_elt, session, content_name, transport_data, client):
+        """Called when proxy has been activated (or has sent an error)
+
+        @param proxy_elt(domish.Element): <activated/> or <proxy-error/> element
+            (see XEP-0260 §2.4)
+        @param session(dict):  session data
+        @param content_name(unicode): name of the current content
+        @param transport_data(dict): transport data
+        @param client(unicode): %(doc_client)s
+        """
+        try:
+            activation_d = transport_data.pop('activation_d')
+        except KeyError:
+            log.warning(u"Received unexpected transport-info for proxy activation")
+
+        if proxy_elt.name == 'activated':
+            activation_d.callback(None)
+        else:
+            activation_d.errback(ProxyError())
+
+    @defer.inlineCallbacks
+    def jingleHandler(self, client, action, session, content_name, transport_elt):
+        content_data = session['contents'][content_name]
+        transport_data = content_data['transport_data']
+
+        if action in (self._j.A_ACCEPTED_ACK, self._j.A_PREPARE_RESPONDER):
+            pass
+
+        elif action == self._j.A_SESSION_ACCEPT:
+            # initiator side, we select a candidate in the ones sent by responder
+            assert 'peer_candidates' not in transport_data
+            transport_data['peer_candidates'] = self._parseCandidates(transport_elt)
+
+        elif action == self._j.A_START:
+            session_hash = transport_data['session_hash']
+            peer_candidates = transport_data['peer_candidates']
+            stream_object = content_data['stream_object']
+            self._s5b.associateStreamObject(client, session_hash, stream_object)
+            stream_d = transport_data.pop('stream_d')
+            stream_d.chainDeferred(content_data['finished_d'])
+            peer_session_hash = transport_data['peer_session_hash']
+            d = self._s5b.getBestCandidate(client, peer_candidates, session_hash, peer_session_hash)
+            d.addCallback(self._foundPeerCandidate, session, transport_data, content_name, client)
+
+        elif action == self._j.A_SESSION_INITIATE:
+            # responder side, we select a candidate in the ones sent by initiator
+            # and we give our candidates
+            assert 'peer_candidates' not in transport_data
+            sid = transport_data['sid'] = transport_elt['sid']
+            session_hash = transport_data['session_hash'] = self._s5b.getSessionHash(client.jid, session['peer_jid'], sid)
+            peer_session_hash = transport_data['peer_session_hash'] = self._s5b.getSessionHash(session['peer_jid'], client.jid, sid) # requester and target are inversed for peer candidates
+            peer_candidates = transport_data['peer_candidates'] = self._parseCandidates(transport_elt)
+            stream_object = content_data['stream_object']
+            stream_d = self._s5b.registerHash(client, session_hash, stream_object)
+            stream_d.chainDeferred(content_data['finished_d'])
+            d = self._s5b.getBestCandidate(client, peer_candidates, session_hash, peer_session_hash)
+            d.addCallback(self._foundPeerCandidate, session, transport_data, content_name, client)
+            candidates = yield self._s5b.getCandidates(client)
+            # we remove duplicate candidates
+            candidates = [candidate for candidate in candidates if candidate not in peer_candidates]
+
+            transport_data['candidates'] = candidates
+            # we can now build a new <transport> element with our candidates
+            transport_elt = self._buildCandidates(session, candidates, sid, session_hash, client)
+
+        elif action == self._j.A_TRANSPORT_INFO:
+            # transport-info can be about candidate or proxy activation
+            candidate_elt = None
+
+            for method, names in ((self._candidateInfo, ('candidate-used', 'candidate-error')),
+                                  (self._proxyActivationInfo, ('activated', 'proxy-error'))):
+                for name in names:
+                    try:
+                        candidate_elt = transport_elt.elements(NS_JINGLE_S5B, name).next()
+                    except StopIteration:
+                        continue
+                    else:
+                        method(candidate_elt, session, content_name, transport_data, client)
+                        break
+
+            if candidate_elt is None:
+                log.warning(u"Unexpected transport element: {}".format(transport_elt.toXml()))
+        elif action == self._j.A_DESTROY:
+            # the transport is replaced (fallback ?), We need mainly to kill XEP-0065 session.
+            # note that sid argument is not necessary for sessions created by this plugin
+            self._s5b.killSession(None, transport_data['session_hash'], None, client)
+        else:
+            log.warning(u"FIXME: unmanaged action {}".format(action))
+
+        defer.returnValue(transport_elt)
+
+    def jingleTerminate(self, client, action, session, content_name, reason_elt):
+        if reason_elt.decline:
+            log.debug(u"Session declined, deleting S5B session")
+            # we just need to clean the S5B session if it is declined
+            content_data = session['contents'][content_name]
+            transport_data = content_data['transport_data']
+            self._s5b.killSession(None, transport_data['session_hash'], None, client)
+
+    def _doFallback(self, feature_checked, session, content_name, client):
+        """Do the fallback, method called once feature is checked
+
+         @param feature_checked(bool): True if other peer can do IBB
+         """
+        if not feature_checked:
+            log.warning(u"Other peer can't manage jingle IBB, be have to terminate the session")
+            self._j.terminate(client, self._j.REASON_CONNECTIVITY_ERROR, session)
+        else:
+            self._j.transportReplace(client, self._jingle_ibb.NAMESPACE, session, content_name)
+
+    def doFallback(self, session, content_name, client):
+        """Fallback to IBB transport, used in last resort
+
+        @param session(dict):  session data
+        @param content_name(unicode): name of the current content
+        @param client(unicode): %(doc_client)s
+        """
+        if session['role'] != self._j.ROLE_INITIATOR:
+            # only initiator must do the fallback, see XEP-0260 §3
+            return
+        if self._jingle_ibb is None:
+            log.warning(u"Jingle IBB (XEP-0261) plugin is not available, we have to close the session")
+            self._j.terminate(client, self._j.REASON_CONNECTIVITY_ERROR, session)
+        else:
+            d = self.host.hasFeature(client, self._jingle_ibb.NAMESPACE, session['peer_jid'])
+            d.addCallback(self._doFallback, session, content_name, client)
+        return d
+
+
+class XEP_0260_handler(XMPPHandler):
+    implements(iwokkel.IDisco)
+
+    def getDiscoInfo(self, requestor, target, nodeIdentifier=''):
+        return [disco.DiscoFeature(NS_JINGLE_S5B)]
+
+    def getDiscoItems(self, requestor, target, nodeIdentifier=''):
+        return []