path: root/spec/Channel_Interface_SASL_Authentication.xml

<?xml version="1.0" ?>
<node name="/Channel_Interface_SASL_Authentication"
      xmlns:tp="http://telepathy.freedesktop.org/wiki/DbusSpec#extensions-v0">
  <tp:copyright> Copyright © 2010 Collabora Limited </tp:copyright>
  <tp:license xmlns="http://www.w3.org/1999/xhtml">
    <p>This library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.</p>

<p>This library 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
Lesser General Public License for more details.</p>

<p>You should have received a copy of the GNU Lesser General Public
License along with this library; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.</p>
  </tp:license>
  <interface name="org.freedesktop.Telepathy.Channel.Interface.SASLAuthentication.DRAFT2"
      tp:causes-havoc="experimental">
    <tp:added version="0.21.UNRELEASED">(draft 2)</tp:added>
    <tp:requires interface="org.freedesktop.Telepathy.Channel"/>
    <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
      <p>A channel interface for SASL authentication,
        as defined by
        <a href="http://tools.ietf.org/html/rfc4422">RFC 4422</a>.
        When this interface appears on a <tp:dbus-ref
          namespace="ofdT.Channel.Type">ServerAuthentication.DRAFT2</tp:dbus-ref>
        channel, it represents authentication with the server. In future,
        it could also be used to authenticate with secondary services,
        or even to authenticate end-to-end connections with contacts.</p>

      <p>In any protocol that requires a password, the connection manager can
        use this channel to let a user interface carry out a simple SASL-like
        handshake with it, as a way to get the user's credentials
        interactively. This can be used to connect to protocols that may
        require a password, without requiring that the password is saved in
        the <tp:dbus-ref
          namespace="ofdT">Account.Parameters</tp:dbus-ref>.</p>

      <p>In some protocols, such as XMPP, authentication with the server
        is also carried out using SASL. In these protocols, a channel with this
        interface can provide a simple 1:1 mapping of the SASL negotiations
        taking place in the protocol, allowing more advanced clients to
        perform authentication via SASL mechanisms not known to the
        connection manager.</p>

      <tp:rationale>
        <p>By providing SASL directly when the protocol supports it, we can
          use mechanisms like Kerberos or Google's <code>X-GOOGLE-TOKEN</code>
          without specific support in the connection manager.</p>
      </tp:rationale>

      <p>For channels managed by a
        <tp:dbus-ref namespace="ofdT">ChannelDispatcher</tp:dbus-ref>,
        only the channel's <tp:dbus-ref
          namespace="ofdT.Client">Handler</tp:dbus-ref> may call the
        methods on this interface. Other clients MAY observe the
        authentication process by watching its signals and properties.</p>

      <tp:rationale>
        <p>There can only be one Handler, which is a good fit for SASL's
          1-1 conversation between a client and a server.</p>
      </tp:rationale>
    </tp:docstring>

    <tp:simple-type name="SASL_Mechanism" type="s"
      array-name="SASL_Mechanism_List">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>A SASL mechanism, as defined by
          <a href="http://tools.ietf.org/html/rfc4422">RFC 4422</a>
          and registered in
          <a href="http://www.iana.org/assignments/sasl-mechanisms">the
            IANA registry of SASL mechanisms</a>, or an unregistered
          SASL mechanism such as <code>X-GOOGLE-TOKEN</code> used in the
          same contexts.</p>

        <p>As a special case, pseudo-mechanisms starting with
          <code>X-TELEPATHY-</code> are defined by this specification.
          Use of these pseudo-mechanisms indicates that the user's credentials
          are to be passed to the connection manager, which will then use
          them for authentication with the service, either by implementing
          the client side of some SASL mechanisms itself or by using a
          non-SASL protocol. The only such pseudo-mechanism currently
          defined is <code>X-TELEPATHY-PASSWORD</code>.</p>

        <p>The <code>X-TELEPATHY-PASSWORD</code> mechanism is extremely
          simple:</p>

        <ul>
          <li>The client MUST call
            <tp:member-ref>StartMechanismWithData</tp:member-ref>, with
            Initial_Data set to the password encoded in UTF-8.
            For simplicity, calling <tp:member-ref>StartMechanism</tp:member-ref>
            followed by calling <tp:member-ref>Respond</tp:member-ref> is not
            allowed in this mechanism.</li>

          <li>The connection manager uses the password, together with
            authentication details from the Connection parameters, to
            authenticate itself to the server.</li>

          <li>When the connection manager finishes its attempt to authenticate
            to the server, the channel's state changes to
            either SASL_Status_Server_Succeeded or
            SASL_Status_Server_Failed as appropriate.</li>
        </ul>
      </tp:docstring>
    </tp:simple-type>

    <property name="AvailableMechanisms"
      tp:name-for-bindings="Available_Mechanisms"
      type="as" tp:type="SASL_Mechanism[]"
      access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>The SASL mechanisms as offered by the server, plus any
          pseudo-SASL mechanisms supported by the connection manager for
          credentials transfer. For instance, in a protocol that
          natively uses SASL (like XMPP), this might be
          <code>[ "X-TELEPATHY-PASSWORD", "PLAIN", "DIGEST-MD5",
            "SCRAM-SHA-1" ]</code>.</p>

        <p>To make it possible to implement a very simple password-querying
          user interface without knowledge of any particular SASL mechanism,
          implementations of this interface MUST implement the
          pseudo-mechanism <code>X-TELEPATHY-PASSWORD</code>.</p>
      </tp:docstring>
    </property>

    <property name="HasInitialData" tp:name-for-bindings="Has_Initial_Data"
      type="b" access="read" tp:immutable="yes">
      <tp:docstring>
        If true, <tp:member-ref>StartMechanismWithData</tp:member-ref>
        can be expected to work (this is the case in most, but not all,
        protocols). If false, <tp:member-ref>StartMechanism</tp:member-ref>
        must be used instead.
      </tp:docstring>
    </property>

    <property name="CanTryAgain" tp:name-for-bindings="Can_Try_Again"
      type="b" access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>If true, <tp:member-ref>StartMechanism</tp:member-ref> and (if
          supported) <tp:member-ref>StartMechanismWithData</tp:member-ref>
          can be expected to work when in one of the Failed states. If
          false, the only thing you can do after failure is to close the
          channel.</p>

        <tp:rationale>
          <p>Retrying isn't required to work, although some protocols and
            implementations allow it.</p>
        </tp:rationale>
      </tp:docstring>
    </property>

    <property name="Encrypted"
      tp:name-for-bindings="Encrypted" type="b"
      access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>True if this authentication process occurs over an encrypted
          connection. This <strong>does not</strong> imply that steps have
          been taken to avoid man-in-the-middle attacks.</p>

        <tp:rationale>
          <p>For future support for <a
              href="http://tools.ietf.org/html/rfc5056">RFC 5056 Channel
              Binding</a> it is desirable to be able to use some SASL
            mechanisms over an encrypted connection to an unverified peer,
            which can prove that it is the desired destination during
            the SASL negotiation.</p>
        </tp:rationale>

        <p>Clients MAY use the combination of this property and
          <tp:member-ref>Verified</tp:member-ref> to decide whether the
          <code>PLAIN</code> mechanism is acceptable, for instance.</p>
      </tp:docstring>
    </property>

    <property name="Verified"
      tp:name-for-bindings="Verified" type="b"
      access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>True if this authentication process occurs over a connection
          that is protected against tampering, and has been verified to
          be with the desired destination: for instance, one where TLS
          was previously negotiated, and the TLS certificate has been
          verified against a configured certificate authority or
          accepted by the user.</p>

        <p>Clients MAY use the combination of this property and
          <tp:member-ref>Encrypted</tp:member-ref> to decide whether the
        <code>PLAIN</code> mechanism is acceptable, for instance.</p>
      </tp:docstring>
    </property>

    <property type="u" tp:type="SASL_Status" access="read"
      name="SASLStatus" tp:name-for-bindings="SASL_Status">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        The current status of this channel.
        Change notification is via the
        <tp:member-ref>SASLStatusChanged</tp:member-ref> signal.
      </tp:docstring>
    </property>

    <property type="s" tp:type="DBus_Error_Name" access="read"
      name="SASLError" tp:name-for-bindings="SASL_Error">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>The reason for the <tp:member-ref>SASLStatus</tp:member-ref>, or
          an empty string if the state is neither
          Server_Failed nor Client_Failed.</p>

        <p>In particular, an ordinary authentication failure (as would
          be produced for an incorrect password) SHOULD be represented by
          <tp:error-ref>AuthenticationFailed</tp:error-ref>,
          cancellation by the user's request SHOULD be represented
          by <tp:error-ref>Cancelled</tp:error-ref>, and
          cancellation by a local process due to inconsistent or invalid
          challenges from the server SHOULD be represented by
          <tp:error-ref>ServiceConfused</tp:error-ref>.</p>

        <p>If this interface appears on a <tp:dbus-ref
            namespace="ofdT.Channel.Type">ServerAuthentication.DRAFT2</tp:dbus-ref>
          channel, and connection to the server fails with an authentication
          failure, this error code SHOULD be copied into the
          <tp:dbus-ref
            namespace="ofdT">Connection.ConnectionError</tp:dbus-ref>
          signal.</p>
      </tp:docstring>
    </property>

    <property name="SASLErrorDetails"
      tp:name-for-bindings="SASL_Error_Details"
      access="read" type="a{sv}" tp:type="String_Variant_Map">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>If <tp:member-ref>SASLError</tp:member-ref> is non-empty,
          any additional information about the last
          disconnection; otherwise, the empty map. The keys and values are
          the same as for the second argument of
          <tp:dbus-ref
            namespace="ofdT">Connection.ConnectionError</tp:dbus-ref>.</p>

        <p>If this interface appears on a <tp:dbus-ref
            namespace="ofdT.Channel.Type">ServerAuthentication.DRAFT2</tp:dbus-ref>
          channel, and connection to the server fails with an authentication
          failure, these details SHOULD be copied into the
          <tp:dbus-ref
            namespace="ofdT">Connection.ConnectionError</tp:dbus-ref>
          signal.</p>
      </tp:docstring>
    </property>

    <property name="AuthorizationIdentity"
      tp:name-for-bindings="Authorization_Identity"
      type="s" access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>The identity for which authorization is being attempted,
          typically the 'account' from the <tp:dbus-ref
            namespace="ofdT.ConnectionManager">RequestConnection</tp:dbus-ref>
          parameters, normalized and formatted according to the
          conventions used for SASL in this protocol.</p>

        <tp:rationale>
          <p>The normalization used for SASL might not be the same
            normalization used elsewhere: for instance, in a protocol
            with email-like identifiers such as XMPP or SIP, the user
            "juliet@example.com" might have to authenticate to the
            example.com server via SASL PLAIN as "juliet".</p>
        </tp:rationale>

        <p>This is usually achieved by using the authorization identity for
          authentication, but an advanced Handler could offer the option
          to authenticate under a different identity.</p>

        <p>The terminology used here is that the authorization identity
          is who you want to act as, and the authentication identity is
          used to prove that you may do so. For instance, if Juliet is
          authorized to access a role account, "sysadmin@example.com",
          and act on its behalf, it might be possible to authenticate
          as "juliet@example.com" with her own password, but request to
          be authorized as "sysadmin@example.com" instead of her own
          account. See
          <a href="http://tools.ietf.org/html/rfc4422#section-3.4.1">RFC
            4422 §3.4.1</a> for more details.</p>

        <tp:rationale>
          <p>In SASL the authorization identity is normally guessed from
            the authentication identity, but the information available
            to the connection manager is the identity for which
            authorization is required, such as the desired JID in XMPP,
            so that's what we signal to UIs; it's up to the UI to
            choose whether to authenticate as the authorization identity
            or some other identity.</p>

          <p>As a concrete example, the "sysadmin" XMPP account mentioned
            above would have <code>{ 'account': 'sysadmin@example.com' }</code>
            in its Parameters, and this property would also be
            'sysadmin@example.com'. A simple Handler would
            merely prompt for sysadmin@example.com's password,
            and use that JID as both the authorization and authentication
            identity, which might result in SASL PLAIN authentication with the
            initial response
            '\000sysadmin@example.com\000root'.</p>

          <p>A more advanced Handler might also ask for an authentication
            identity, defaulting to 'sysadmin@example.com'; if Juliet
            provided authentication identity 'juliet@example.com' and
            password 'romeo', the Handler might perform SASL PLAIN
            authentication using the initial response
            'sysadmin@example.com\000juliet@example.com\000romeo'.</p>
        </tp:rationale>
      </tp:docstring>
    </property>

    <property name="DefaultRealm" tp:name-for-bindings="Default_Realm"
      type="s" access="read" tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>The default realm (as defined in
          <a href="http://tools.ietf.org/html/rfc2831#section-2.1.1">RFC
            2831</a>) to use for authentication, if the server does not
          supply one.</p>

        <tp:rationale>
          <p>The server is not required to provide a realm; if it doesn't,
            the client is expected to ask the user or provide a sensible
            default, typically the requested DNS name of the server.
            In some implementations of <code>DIGEST-MD5</code>, the
            server does not specify a realm, but expects that the client
            will choose a particular default, and authentication will
            fail if the client's default is different. Connection
            managers for protocols where this occurs are more easily able
            to work around these implementations than a generic client
            would be.</p>
        </tp:rationale>
      </tp:docstring>
    </property>

    <property name="SASLContext" tp:name-for-bindings="SASL_Context"
      type="a{sv}" tp:type="String_Variant_Map" access="read"
      tp:immutable="yes">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Additional protocol- or mechanism-specific context for the
          authentication. Only one well-known key is currently defined:</p>

        <dl>
          <dt>jabber-stream-id (string)</dt>
          <dd>The <code>id</code> attribute of the XMPP <code>stream</code>
            element, as used in <a
              href="http://xmpp.org/extensions/xep-0078.html">the digest
              mechanism historically used in Jabber</a>.</dd>
        </dl>
      </tp:docstring>
    </property>

    <method name="StartMechanism" tp:name-for-bindings="Start_Mechanism">
      <arg direction="in" name="Mechanism" type="s" tp:type="SASL_Mechanism">
        <tp:docstring>
          The chosen mechanism.
        </tp:docstring>
      </arg>
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Start an authentication try using <var>Mechanism</var>, without
          sending initial data (an "initial response" as defined in RFC
          4422).</p>

        <tp:rationale>
          <p>This method is appropriate for mechanisms where the client
            cannot send anything until it receives a challenge from the
            server, such as <code>DIGEST-MD5</code>.</p>
        </tp:rationale>
      </tp:docstring>

      <tp:possible-errors>
        <tp:error name="org.freedesktop.Telepathy.Error.NotAvailable">
          <tp:docstring>
            The channel is not in a state where starting authentication makes
            sense (i.e. SASL_Status_Not_Started, or (if
            <tp:member-ref>CanTryAgain</tp:member-ref> is true)
            SASL_Status_Server_Failed or
            SASL_Status_Client_Failed). You should call
            <tp:member-ref>AbortSASL</tp:member-ref> and wait for
            SASL_Status_Client_Failed before starting another attempt.
          </tp:docstring>
        </tp:error>
        <tp:error name="org.freedesktop.Telepathy.Error.NetworkError"/>
        <tp:error name="org.freedesktop.Telepathy.Error.NotImplemented">
          <tp:docstring>
            The server or connection manager doesn't implement the given
            SASL mechanism. Choose a SASL mechanism from
            <tp:member-ref>AvailableMechanisms</tp:member-ref>, or abort
            authentication if none of them are suitable.
          </tp:docstring>
        </tp:error>
      </tp:possible-errors>
    </method>

    <method name="StartMechanismWithData"
      tp:name-for-bindings="Start_Mechanism_With_Data">
      <arg direction="in" name="Mechanism" type="s" tp:type="SASL_Mechanism">
        <tp:docstring>
          The chosen mechanism.
        </tp:docstring>
      </arg>
      <arg direction="in" name="Initial_Data" type="ay">
        <tp:docstring>
          Initial data (an "initial response" in RFC 4422's terminology) to send
          with the mechanism.
        </tp:docstring>
      </arg>
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Start an authentication try using <var>Mechanism</var>, and send
          <var>Initial_Data</var> as the "initial response" defined in
          <a href="http://tools.ietf.org/html/rfc4422#section-3.3">RFC 4422
            §3.3</a>.</p>

        <p>If the underlying protocol does not make it possible to send
          initial data, this method will fail.</p>

        <tp:rationale>
          <p>This method is appropriate for mechanisms where the client may
            send data first, such as <code>PLAIN</code>.</p>

          <p>Having two methods allows any mechanism where it makes a difference
            to distinguish between the absence of an initial response
            (<tp:member-ref>StartMechanism</tp:member-ref>) and a zero-byte
            initial response (StartMechanismWithData, with Initial_Data
            empty).</p>
        </tp:rationale>
      </tp:docstring>

      <tp:possible-errors>
        <tp:error name="org.freedesktop.Telepathy.Error.NotAvailable">
          <tp:docstring>
            The channel is not in a state where starting authentication makes
            sense (i.e. SASL_Status_Not_Started, or (if
            <tp:member-ref>CanTryAgain</tp:member-ref> is true)
            SASL_Status_Server_Failed or
            SASL_Status_Client_Failed). You should call
            <tp:member-ref>AbortSASL</tp:member-ref> and wait for
            SASL_Status_Client_Failed before starting another attempt.
          </tp:docstring>
        </tp:error>
        <tp:error name="org.freedesktop.Telepathy.Error.NetworkError"/>
        <tp:error name="org.freedesktop.Telepathy.Error.NotImplemented">
          <tp:docstring>
            The server or connection manager doesn't implement the given
            SASL mechanism (choose one from
            <tp:member-ref>AvailableMechanisms</tp:member-ref>, or abort
            authentication if none of them are suitable), or doesn't allow
            initial data to be sent (as indicated by
            <tp:member-ref>HasInitialData</tp:member-ref>; call
            <tp:member-ref>StartMechanism</tp:member-ref> instead).
          </tp:docstring>
        </tp:error>
      </tp:possible-errors>
    </method>

    <method name="Respond" tp:name-for-bindings="Respond">
      <arg direction="in" name="Response_Data" type="ay">
        <tp:docstring>
          The response data.
        </tp:docstring>
      </arg>
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Send a response to the the last challenge received via
          <tp:member-ref>NewChallenge</tp:member-ref>.</p>
      </tp:docstring>

      <tp:possible-errors>
        <tp:error name="org.freedesktop.Telepathy.Error.NotAvailable">
          <tp:docstring>
            Either the state is not In_Progress, or no challenge has been
            received yet, or you have already responded to the last challenge.
          </tp:docstring>
        </tp:error>
        <tp:error name="org.freedesktop.Telepathy.Error.NetworkError"/>
      </tp:possible-errors>
    </method>

    <method name="AcceptSASL" tp:name-for-bindings="Accept_SASL">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>If the channel's status is SASL_Status_Server_Succeeded,
          this method confirms successful authentication and advances
          the status of the channel to SASL_Status_Succeeded.</p>

        <p>If the channel's status is SASL_Status_In_Progress, calling this
          method indicates that the last
          <tp:member-ref>NewChallenge</tp:member-ref> signal was in fact
          additional data sent after a successful SASL negotiation, and
          declares that from the client's point of view, authentication
          was successful. This advances the state of the channel to
          SASL_Status_Client_Accepted.</p>

        <p>In mechanisms where the server authenticates itself to the client,
          calling this method indicates that the client considers this to have
          been successful.</p>
      </tp:docstring>

      <tp:possible-errors>
        <tp:error name="org.freedesktop.Telepathy.Error.NotAvailable">
          <tp:docstring>
            Either the state is neither In_Progress nor Server_Succeeded, or no
            challenge has been received yet, or you have already responded to
            the last challenge.
          </tp:docstring>
        </tp:error>
        <tp:error name="org.freedesktop.Telepathy.Error.NetworkError"/>
      </tp:possible-errors>
    </method>

    <method name="AbortSASL" tp:name-for-bindings="Abort_SASL">
      <arg direction="in" name="Reason" type="u" tp:type="SASL_Abort_Reason">
        <tp:docstring>
          Reason for abort.
        </tp:docstring>
      </arg>
      <arg direction="in" name="Debug_Message" type="s">
        <tp:docstring>
          Debug message for abort.
        </tp:docstring>
      </arg>
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Abort the current authentication try.</p>

        <p>If the current status is SASL_Status_Server_Failed or
          SASL_Status_Client_Failed, this method returns successfully, but has
          no further effect. Otherwise, it changes the channel's state to
          SASL_Status_Client_Failed, with an appropriate error name and
          reason code.</p>
      </tp:docstring>
    </method>

    <signal name="SASLStatusChanged" tp:name-for-bindings="SASL_Status_Changed">
      <tp:docstring>
        Emitted when the status of the channel changes.
      </tp:docstring>
      <arg type="u" tp:type="SASL_Status" name="Status">
        <tp:docstring>
          The new value of <tp:member-ref>SASLStatus</tp:member-ref>.
        </tp:docstring>
      </arg>
      <arg type="s" tp:type="DBus_Error_Name" name="Reason">
        <tp:docstring>
          The new value of <tp:member-ref>SASLError</tp:member-ref>.
        </tp:docstring>
      </arg>
      <arg type="a{sv}" tp:type="String_Variant_Map" name="Details">
        <tp:docstring>
          The new value of <tp:member-ref>SASLErrorDetails</tp:member-ref>.
        </tp:docstring>
      </arg>
    </signal>

    <signal name="NewChallenge" tp:name-for-bindings="New_Challenge">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>Emitted when a new challenge is received from the server, or when
          a message indicating successful authentication and containing
          additional data is received from the server.</p>

        <p>When the channel's handler is ready to proceed, it should respond
          to the challenge by calling <tp:member-ref>Respond</tp:member-ref>,
          or respond to the additional data by calling
          <tp:member-ref>AcceptSASL</tp:member-ref>. Alternatively, it may call
          <tp:member-ref>AbortSASL</tp:member-ref> to abort authentication.</p>
      </tp:docstring>
      <arg name="Challenge_Data" type="ay">
        <tp:docstring>
          The challenge data or additional data from the server.
        </tp:docstring>
      </arg>
    </signal>

    <tp:enum name="SASL_Abort_Reason" type="u">
      <tp:docstring xmlns="http://www.w3.org/1999/xhtml">
        <p>A reason why SASL authentication was aborted by the client.</p>
      </tp:docstring>

      <tp:enumvalue suffix="Invalid_Challenge" value="0">
        <tp:docstring>
          The server sent an invalid challenge or data.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="User_Abort" value="1">
        <tp:docstring>
          The user aborted the authentication.
        </tp:docstring>
      </tp:enumvalue>
    </tp:enum>

    <tp:enum name="SASL_Status" type="u">
      <tp:enumvalue suffix="Not_Started" value="0">
        <tp:docstring>
          The initial state. The Handler SHOULD either
          call <tp:member-ref>AbortSASL</tp:member-ref>, or connect to the
          <tp:member-ref>NewChallenge</tp:member-ref> signal then call
          <tp:member-ref>StartMechanism</tp:member-ref> or
          <tp:member-ref>StartMechanismWithData</tp:member-ref>.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="In_Progress" value="1">
        <tp:docstring>
          The challenge/response exchange is in progress. The Handler SHOULD
          call either <tp:member-ref>Respond</tp:member-ref> or
          <tp:member-ref>AcceptSASL</tp:member-ref> exactly once per emission
          of <tp:member-ref>NewChallenge</tp:member-ref>, or call
          <tp:member-ref>AbortSASL</tp:member-ref> at any time.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="Server_Succeeded" value="2">
        <tp:docstring>
          The server has indicated successful authentication, and the
          connection manager is waiting for confirmation from the Handler.
          The Handler must call either <tp:member-ref>AcceptSASL</tp:member-ref> or
          <tp:member-ref>AbortSASL</tp:member-ref> to indicate whether it
          considers authentication to have been successful.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="Client_Accepted" value="3">
        <tp:docstring>
          The Handler has indicated successful authentication, and the
          connection manager is waiting for confirmation from the server.
          The state will progress to either Succeeded or Server_Failed when
          confirmation is received.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="Succeeded" value="4">
        <tp:docstring>
          Everyone is happy (the server sent success, and the client has called
          <tp:member-ref>AcceptSASL</tp:member-ref>). The Handler MUST call
          <tp:dbus-ref
            namespace="org.freedesktop.Telepathy.Channel">Close</tp:dbus-ref>
          to close the channel.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="Server_Failed" value="5">
        <tp:docstring>
          The server has indicated an authentication failure.
          If <tp:member-ref>CanTryAgain</tp:member-ref> is true,
          the client may try to authenticate again, by calling
          <tp:member-ref>StartMechanism</tp:member-ref> or
          <tp:member-ref>StartMechanismWithData</tp:member-ref> again.
          Otherwise, it should give up completely, by calling <tp:dbus-ref
            namespace="org.freedesktop.Telepathy.Channel">Close</tp:dbus-ref>
          on the channel.
        </tp:docstring>
      </tp:enumvalue>
      <tp:enumvalue suffix="Client_Failed" value="6">
        <tp:docstring>
          The client has indicated an authentication failure. The
          possible actions are the same as for Server_Failed.
        </tp:docstring>
      </tp:enumvalue>
    </tp:enum>

  </interface>
</node>
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