view sat/plugins/plugin_xep_0115.py @ 2646:712cb4ff3e13

core: new EncryptionHandler class which manage encrypted session as a core feature: Plugin handling encryption can now register using host.registerEncryptionPlugin, and an encryption session can now be started using messageEncryptionStart bridge method. This will make encryption handling more easy, as we now know if a session is clear or e2e encrypted, and which plugin handle it.
author Goffi <goffi@goffi.org>
date Sun, 29 Jul 2018 19:22:56 +0200
parents 56f94936df1e
children 378188abe941
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#!/usr/bin/env python2
# -*- coding: utf-8 -*-

# SAT plugin for managing xep-0115
# 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 twisted.words.xish import domish
from twisted.words.protocols.jabber import jid
from twisted.internet import defer, error
from zope.interface import implements
from wokkel import disco, iwokkel

try:
    from twisted.words.protocols.xmlstream import XMPPHandler
except ImportError:
    from wokkel.subprotocols import XMPPHandler

PRESENCE = "/presence"
NS_ENTITY_CAPABILITY = "http://jabber.org/protocol/caps"
NS_CAPS_OPTIMIZE = "http://jabber.org/protocol/caps#optimize"
CAPABILITY_UPDATE = PRESENCE + '/c[@xmlns="' + NS_ENTITY_CAPABILITY + '"]'

PLUGIN_INFO = {
    C.PI_NAME: "XEP 0115 Plugin",
    C.PI_IMPORT_NAME: "XEP-0115",
    C.PI_TYPE: "XEP",
    C.PI_MODES: C.PLUG_MODE_BOTH,
    C.PI_PROTOCOLS: ["XEP-0115"],
    C.PI_DEPENDENCIES: [],
    C.PI_MAIN: "XEP_0115",
    C.PI_HANDLER: "yes",
    C.PI_DESCRIPTION: _("""Implementation of entity capabilities"""),
}


class XEP_0115(object):
    cap_hash = None  # capabilities hash is class variable as it is common to all profiles

    def __init__(self, host):
        log.info(_("Plugin XEP_0115 initialization"))
        self.host = host
        host.trigger.add("Presence send", self._presenceTrigger)

    def getHandler(self, client):
        return XEP_0115_handler(self, client.profile)

    @defer.inlineCallbacks
    def _prepareCaps(self, client):
        # we have to calculate hash for client
        # because disco infos/identities may change between clients

        # optimize check
        client._caps_optimize = yield self.host.hasFeature(client, NS_CAPS_OPTIMIZE)
        if client._caps_optimize:
            log.info(_(u"Caps optimisation enabled"))
            client._caps_sent = False
        else:
            log.warning(_(u"Caps optimisation not available"))

        # hash generation
        _infos = yield client.discoHandler.info(client.jid, client.jid, "")
        disco_infos = disco.DiscoInfo()
        for item in _infos:
            disco_infos.append(item)
        cap_hash = client._caps_hash = self.host.memory.disco.generateHash(disco_infos)
        log.info(
            u"Our capability hash has been generated: [{cap_hash}]".format(
                cap_hash=cap_hash
            )
        )
        log.debug(u"Generating capability domish.Element")
        c_elt = domish.Element((NS_ENTITY_CAPABILITY, "c"))
        c_elt["hash"] = "sha-1"
        c_elt["node"] = C.APP_URL
        c_elt["ver"] = cap_hash
        client._caps_elt = c_elt
        if client._caps_optimize:
            client._caps_sent = False
        if cap_hash not in self.host.memory.disco.hashes:
            self.host.memory.disco.hashes[cap_hash] = disco_infos
            self.host.memory.updateEntityData(
                client.jid, C.ENTITY_CAP_HASH, cap_hash, profile_key=client.profile
            )

    def _presenceAddElt(self, client, obj):
        if client._caps_optimize:
            if client._caps_sent:
                return
            client.caps_sent = True
        obj.addChild(client._caps_elt)

    def _presenceTrigger(self, client, obj, presence_d):
        if not hasattr(client, "_caps_optimize"):
            presence_d.addCallback(lambda __: self._prepareCaps(client))

        presence_d.addCallback(lambda __: self._presenceAddElt(client, obj))
        return True


class XEP_0115_handler(XMPPHandler):
    implements(iwokkel.IDisco)

    def __init__(self, plugin_parent, profile):
        self.plugin_parent = plugin_parent
        self.host = plugin_parent.host
        self.profile = profile

    def connectionInitialized(self):
        self.xmlstream.addObserver(CAPABILITY_UPDATE, self.update)

    def getDiscoInfo(self, requestor, target, nodeIdentifier=""):
        return [
            disco.DiscoFeature(NS_ENTITY_CAPABILITY),
            disco.DiscoFeature(NS_CAPS_OPTIMIZE),
        ]

    def getDiscoItems(self, requestor, target, nodeIdentifier=""):
        return []

    def update(self, presence):
        """
        Manage the capabilities of the entity

        Check if we know the version of this capabilities and get the capabilities if necessary
        """
        from_jid = jid.JID(presence["from"])
        c_elem = presence.elements(NS_ENTITY_CAPABILITY, "c").next()
        try:
            c_ver = c_elem["ver"]
            c_hash = c_elem["hash"]
            c_node = c_elem["node"]
        except KeyError:
            log.warning(_(u"Received invalid capabilities tag: %s") % c_elem.toXml())
            return

        if c_ver in self.host.memory.disco.hashes:
            # we already know the hash, we update the jid entity
            log.debug(
                u"hash [%(hash)s] already in cache, updating entity [%(jid)s]"
                % {"hash": c_ver, "jid": from_jid.full()}
            )
            self.host.memory.updateEntityData(
                from_jid, C.ENTITY_CAP_HASH, c_ver, profile_key=self.profile
            )
            return

        if c_hash != "sha-1":  # unknown hash method
            log.warning(
                _(
                    u"Unknown hash method for entity capabilities: [%(hash_method)s] (entity: %(jid)s, node: %(node)s)"
                )
                % {"hash_method": c_hash, "jid": from_jid, "node": c_node}
            )

        def cb(dummy):
            computed_hash = self.host.memory.getEntityDatum(
                from_jid, C.ENTITY_CAP_HASH, self.profile
            )
            if computed_hash != c_ver:
                log.warning(
                    _(
                        u"Computed hash differ from given hash:\ngiven: [%(given_hash)s]\ncomputed: [%(computed_hash)s]\n(entity: %(jid)s, node: %(node)s)"
                    )
                    % {
                        "given_hash": c_ver,
                        "computed_hash": computed_hash,
                        "jid": from_jid,
                        "node": c_node,
                    }
                )

        def eb(failure):
            if isinstance(failure.value, error.ConnectionDone):
                return
            msg = (
                failure.value.condition
                if hasattr(failure.value, "condition")
                else failure.getErrorMessage()
            )
            log.error(
                _(u"Couldn't retrieve disco info for {jid}: {error}").format(
                    jid=from_jid.full(), error=msg
                )
            )

        d = self.host.getDiscoInfos(self.parent, from_jid)
        d.addCallbacks(cb, eb)
        # TODO: me must manage the full algorithm described at XEP-0115 #5.4 part 3