onionshare/tails/lib/stem/__init__.py

# Copyright 2011-2013, Damian Johnson and The Tor Project
# See LICENSE for licensing information

"""
Library for working with the tor process.

**Module Overview:**

::

  ControllerError - Base exception raised when using the controller.
    |- ProtocolError - Malformed socket data.
    |- OperationFailed - Tor was unable to successfully complete the operation.
    |  |- UnsatisfiableRequest - Tor was unable to satisfy a valid request.
    |  |  +- CircuitExtensionFailed - Attempt to make or extend a circuit failed.
    |  +- InvalidRequest - Invalid request.
    |     +- InvalidArguments - Invalid request parameters.
    +- SocketError - Communication with the socket failed.
       +- SocketClosed - Socket has been shut down.

.. data:: Runlevel (enum)

  Rating of importance used for event logging.

  =========== ===========
  Runlevel    Description
  =========== ===========
  **ERR**     critical issues that impair tor's ability to function
  **WARN**    non-critical issues the user should be aware of
  **NOTICE**  information that may be helpful to the user
  **INFO**    high level runtime information
  **DEBUG**   low level runtime information
  =========== ===========

.. data:: Signal (enum)

  Signals that the tor process will accept.

  ========================= ===========
  Signal                    Description
  ========================= ===========
  **RELOAD** or **HUP**     reloads our torrc
  **SHUTDOWN** or **INT**   shut down, waiting ShutdownWaitLength first if we're a relay
  **DUMP** or **USR1**      dumps information about open connections and circuits to our log
  **DEBUG** or **USR2**     switch our logging to the DEBUG runlevel
  **HALT** or **TERM**      exit tor immediately
  **NEWNYM**                switch to new circuits, so new application requests don't share any circuits with old ones (this also clears our DNS cache)
  **CLEARDNSCACHE**         clears cached DNS results
  ========================= ===========

.. data:: Flag (enum)

  Flag assigned to tor relays by the authorities to indicate various
  characteristics.

  ================= ===========
  Flag              Description
  ================= ===========
  **AUTHORITY**     relay is a directory authority
  **BADEXIT**       relay shouldn't be used as an exit due to being either problematic or malicious (`wiki <https://trac.torproject.org/projects/tor/wiki/doc/badRelays>`_)
  **BADDIRECTORY**  relay shouldn't be used for directory information
  **EXIT**          relay's exit policy makes it more useful as an exit rather than middle hop
  **FAST**          relay's suitable for high-bandwidth circuits
  **GUARD**         relay's suitable for being an entry guard (first hop)
  **HSDIR**         relay is being used as a v2 hidden service directory
  **NAMED**         relay can be referred to by its nickname
  **RUNNING**       relay is currently usable
  **STABLE**        relay's suitable for long-lived circuits
  **UNNAMED**       relay isn't presently bound to a nickname
  **V2DIR**         relay supports the v2 directory protocol
  **VALID**         relay has been validated
  ================= ===========

.. data:: CircStatus (enum)

  Statuses that a circuit can be in. Tor may provide statuses not in this enum.

  ============ ===========
  CircStatus   Description
  ============ ===========
  **LAUNCHED** new circuit was created
  **BUILT**    circuit finished being created and can accept traffic
  **EXTENDED** circuit has been extended by a hop
  **FAILED**   circuit construction failed
  **CLOSED**   circuit has been closed
  ============ ===========

.. data:: CircBuildFlag (enum)

  Attributes about how a circuit is built. These were introduced in tor version
  0.2.3.11. Tor may provide flags not in this enum.

  ================= ===========
  CircBuildFlag     Description
  ================= ===========
  **ONEHOP_TUNNEL** single hop circuit to fetch directory information
  **IS_INTERNAL**   circuit that won't be used for client traffic
  **NEED_CAPACITY** circuit only includes high capacity relays
  **NEED_UPTIME**   circuit only includes relays with a high uptime
  ================= ===========

.. data:: CircPurpose (enum)

  Description of what a circuit is intended for. These were introduced in tor
  version 0.2.1.6. Tor may provide purposes not in this enum.

  ==================== ===========
  CircPurpose          Description
  ==================== ===========
  **GENERAL**          client traffic or fetching directory information
  **HS_CLIENT_INTRO**  client side introduction point for a hidden service circuit
  **HS_CLIENT_REND**   client side hidden service rendezvous circuit
  **HS_SERVICE_INTRO** server side introduction point for a hidden service circuit
  **HS_SERVICE_REND**  server side hidden service rendezvous circuit
  **TESTING**          testing to see if we're reachable, so we can be used as a relay
  **CONTROLLER**       circuit that was built by a controller
  **MEASURE_TIMEOUT**  circuit being kept around to see how long it takes
  ==================== ===========

.. data:: CircClosureReason (enum)

  Reason that a circuit is being closed or failed to be established. Tor may
  provide reasons not in this enum.

  ========================= ===========
  CircClosureReason         Description
  ========================= ===========
  **NONE**                  no reason given
  **TORPROTOCOL**           violation in the tor protocol
  **INTERNAL**              internal error
  **REQUESTED**             requested by the client via a TRUNCATE command
  **HIBERNATING**           relay is presently hibernating
  **RESOURCELIMIT**         relay is out of memory, sockets, or circuit IDs
  **CONNECTFAILED**         unable to contact the relay
  **OR_IDENTITY**           relay had the wrong OR identification
  **OR_CONN_CLOSED**        connection failed after being established
  **FINISHED**              circuit has expired (see tor's MaxCircuitDirtiness config option)
  **TIMEOUT**               circuit construction timed out
  **DESTROYED**             circuit unexpectedly closed
  **NOPATH**                not enough relays to make a circuit
  **NOSUCHSERVICE**         requested hidden service does not exist
  **MEASUREMENT_EXPIRED**   same as **TIMEOUT** except that it was left open for measurement purposes
  ========================= ===========

.. data:: CircEvent (enum)

  Type of change reflected in a circuit by a CIRC_MINOR event. Tor may provide
  event types not in this enum.

  ===================== ===========
  CircEvent             Description
  ===================== ===========
  **PURPOSE_CHANGED**   circuit purpose or hidden service state has changed
  **CANNIBALIZED**      circuit connections are being reused for a different circuit
  ===================== ===========

.. data:: HiddenServiceState (enum)

  State that a hidden service circuit can have. These were introduced in tor
  version 0.2.3.11. Tor may provide states not in this enum.

  Enumerations fall into four groups based on their prefix...

  ======= ===========
  Prefix  Description
  ======= ===========
  HSCI_*  client-side introduction-point
  HSCR_*  client-side rendezvous-point
  HSSI_*  service-side introduction-point
  HSSR_*  service-side rendezvous-point
  ======= ===========

  ============================= ===========
  HiddenServiceState            Description
  ============================= ===========
  **HSCI_CONNECTING**           connecting to the introductory point
  **HSCI_INTRO_SENT**           sent INTRODUCE1 and awaiting a reply
  **HSCI_DONE**                 received a reply, circuit is closing
  **HSCR_CONNECTING**           connecting to the introductory point
  **HSCR_ESTABLISHED_IDLE**     rendezvous-point established, awaiting an introduction
  **HSCR_ESTABLISHED_WAITING**  introduction received, awaiting a rend
  **HSCR_JOINED**               connected to the hidden service
  **HSSI_CONNECTING**           connecting to the introductory point
  **HSSI_ESTABLISHED**          established introductory point
  **HSSR_CONNECTING**           connecting to the introductory point
  **HSSR_JOINED**               connected to the rendezvous-point
  ============================= ===========

.. data:: RelayEndReason (enum)

  Reasons why the stream is to be closed.

  =================== ===========
  RelayEndReason      Description
  =================== ===========
  **MISC**            none of the following reasons
  **RESOLVEFAILED**   unable to resolve the hostname
  **CONNECTREFUSED**  remote host refused the connection
  **EXITPOLICY**      OR refuses to connect to the destination
  **DESTROY**         circuit is being shut down
  **DONE**            connection has been closed
  **TIMEOUT**         connection timed out
  **NOROUTE**         routing error while contacting the destination
  **HIBERNATING**     relay is temporarily hibernating
  **INTERNAL**        internal error at the relay
  **RESOURCELIMIT**   relay has insufficient resources to service the request
  **CONNRESET**       connection was unexpectedly reset
  **TORPROTOCOL**     violation in the tor protocol
  **NOTDIRECTORY**    directory information requested from a relay that isn't mirroring it
  =================== ===========

.. data:: StreamStatus (enum)

  State that a stream going through tor can have. Tor may provide states not in
  this enum.

  ================= ===========
  StreamStatus      Description
  ================= ===========
  **NEW**           request for a new connection
  **NEWRESOLVE**    request to resolve an address
  **REMAP**         address is being re-mapped to another
  **SENTCONNECT**   sent a connect cell along a circuit
  **SENTRESOLVE**   sent a resolve cell along a circuit
  **SUCCEEDED**     stream has been established
  **FAILED**        stream is detached, and won't be re-established
  **DETACHED**      stream is detached, but might be re-established
  **CLOSED**        stream has closed
  ================= ===========

.. data:: StreamClosureReason (enum)

  Reason that a stream is being closed or failed to be established. This
  includes all values in the :data:`~stem.RelayEndReason` enumeration as
  well as the following. Tor may provide reasons not in this enum.

  ===================== ===========
  StreamClosureReason   Description
  ===================== ===========
  **END**               endpoint has sent a RELAY_END cell
  **PRIVATE_ADDR**      endpoint was a private address (127.0.0.1, 10.0.0.1, etc)
  ===================== ===========

.. data:: StreamSource (enum)

  Cause of a stream being remapped to another address. Tor may provide sources
  not in this enum.

  ============= ===========
  StreamSource  Description
  ============= ===========
  **CACHE**     tor is remapping because of a cached answer
  **EXIT**      exit relay requested the remap
  ============= ===========

.. data:: StreamPurpose (enum)

  Purpsoe of the stream. This is only provided with new streams and tor may
  provide purposes not in this enum.

  ================= ===========
  StreamPurpose     Description
  ================= ===========
  **DIR_FETCH**     fetching directory information (descriptors, consensus, etc)
  **DIR_UPLOAD**    uploading our descriptor to an authority
  **DNS_REQUEST**   user initiated DNS request
  **DIRPORT_TEST**  checking that our directory port is reachable externally
  **USER**          either relaying user traffic or not one of the above categories
  ================= ===========

.. data:: ORStatus (enum)

  State that an OR connection can have. Tor may provide states not in this
  enum.

  =============== ===========
  ORStatus        Description
  =============== ===========
  **NEW**         received OR connection, starting server-side handshake
  **LAUNCHED**    launched outbound OR connection, starting client-side handshake
  **CONNECTED**   OR connection has been established
  **FAILED**      attempt to establish OR connection failed
  **CLOSED**      OR connection has been closed
  =============== ===========

.. data:: ORClosureReason (enum)

  Reason that an OR connection is being closed or failed to be established. Tor
  may provide reasons not in this enum.

  =================== ===========
  ORClosureReason     Description
  =================== ===========
  **DONE**            OR connection shut down cleanly
  **CONNECTREFUSED**  got a ECONNREFUSED when connecting to the relay
  **IDENTITY**        identity of the relay wasn't what we expected
  **CONNECTRESET**    got a ECONNRESET or similar error from relay
  **TIMEOUT**         got a ETIMEOUT or similar error from relay
  **NOROUTE**         got a ENOTCONN, ENETUNREACH, ENETDOWN, EHOSTUNREACH, or similar error from relay
  **IOERROR**         got a different kind of error from relay
  **RESOURCELIMIT**   relay has insufficient resources to service the request
  **MISC**            connection refused for another reason
  =================== ===========

.. data:: AuthDescriptorAction (enum)

  Actions that directory authorities might take with relay descriptors. Tor may
  provide reasons not in this enum.

  ===================== ===========
  AuthDescriptorAction  Description
  ===================== ===========
  **ACCEPTED**          accepting the descriptor as the newest version
  **DROPPED**           descriptor rejected without notifying the relay
  **REJECTED**          relay notified that its descriptor has been rejected
  ===================== ===========

.. data:: StatusType (enum)

  Sources for tor status events. Tor may provide types not in this enum.

  ============= ===========
  StatusType    Description
  ============= ===========
  **GENERAL**   general tor activity, not specifically as a client or relay
  **CLIENT**    related to our activity as a tor client
  **SERVER**    related to our activity as a tor relay
  ============= ===========

.. data:: GuardType (enum)

  Use a guard relay can be for. Tor may provide types not in this enum.

  =========== ===========
  GuardType   Description
  =========== ===========
  **ENTRY**   used to connect to the tor network
  =========== ===========

.. data:: GuardStatus (enum)

  Status a guard relay can have. Tor may provide types not in this enum.

  ============= ===========
  GuardStatus   Description
  ============= ===========
  **NEW**       new guard that we weren't previously using
  **DROPPED**   removed from use as one of our guards
  **UP**        guard is now reachable
  **DOWN**      guard is now unreachable
  **BAD**       consensus or relay considers this relay to be unusable as a guard
  **GOOD**      consensus or relay considers this relay to be usable as a guard
  ============= ===========

.. data:: TimeoutSetType (enum)

  Way in which the timeout value of a circuit is changing. Tor may provide
  types not in this enum.

  =============== ===========
  TimeoutSetType  Description
  =============== ===========
  **COMPUTED**    tor has computed a new timeout based on prior circuits
  **RESET**       timeout reverted to its default
  **SUSPENDED**   timeout reverted to its default until network connectivity has recovered
  **DISCARD**     throwing out timeout value from when the network was down
  **RESUME**      resumed calculations to determine the proper timeout
  =============== ===========
"""

__version__ = '1.1.1'
__author__ = 'Damian Johnson'
__contact__ = 'atagar@torproject.org'
__url__ = 'https://stem.torproject.org/'
__license__ = 'LGPLv3'

__all__ = [
  "descriptor",
  "response",
  "util",
  "connection",
  "control",
  "exit_policy",
  "prereq",
  "process",
  "socket",
  "version",
  "ControllerError",
  "ProtocolError",
  "OperationFailed",
  "UnsatisfiableRequest",
  "CircuitExtensionFailed",
  "InvalidRequest",
  "InvalidArguments",
  "SocketError",
  "SocketClosed",
  "Runlevel",
  "Signal",
  "Flag",
  "CircStatus",
  "CircBuildFlag",
  "CircPurpose",
  "CircClosureReason",
  "CircEvent",
  "HiddenServiceState",
  "RelayEndReason",
  "StreamStatus",
  "StreamClosureReason",
  "StreamSource",
  "StreamPurpose",
  "ORStatus",
  "ORClosureReason",
  "AuthDescriptorAction",
  "StatusType",
  "GuardType",
  "GuardStatus",
  "TimeoutSetType",
]

import stem.util.enum

# Constant to indicate an undefined argument default. Usually we'd use None for
# this, but users will commonly provide None as the argument so need something
# else fairly unique...

UNDEFINED = "<Undefined_ >"


class ControllerError(Exception):
  "Base error for controller communication issues."


class ProtocolError(ControllerError):
  "Malformed content from the control socket."


class OperationFailed(ControllerError):
  """
  Base exception class for failed operations that return an error code

  :var str code: error code returned by Tor
  :var str message: error message returned by Tor or a human readable error
    message
  """

  def __init__(self, code = None, message = None):
    super(ControllerError, self).__init__(message)
    self.code = code
    self.message = message


class UnsatisfiableRequest(OperationFailed):
  """
  Exception raised if Tor was unable to process our request.
  """


class CircuitExtensionFailed(UnsatisfiableRequest):
  """
  An attempt to create or extend a circuit failed.

  :var stem.response.CircuitEvent circ: response notifying us of the failure
  """

  def __init__(self, message, circ = None):
    super(CircuitExtensionFailed, self).__init__(message = message)
    self.circ = circ


class InvalidRequest(OperationFailed):
  """
  Exception raised when the request was invalid or malformed.
  """


class InvalidArguments(InvalidRequest):
  """
  Exception class for requests which had invalid arguments.

  :var str code: error code returned by Tor
  :var str message: error message returned by Tor or a human readable error
    message
  :var list arguments: a list of arguments which were invalid
  """

  def __init__(self, code = None, message = None, arguments = None):
    super(InvalidArguments, self).__init__(code, message)
    self.arguments = arguments


class SocketError(ControllerError):
  "Error arose while communicating with the control socket."


class SocketClosed(SocketError):
  "Control socket was closed before completing the message."

Runlevel = stem.util.enum.UppercaseEnum(
  "DEBUG",
  "INFO",
  "NOTICE",
  "WARN",
  "ERR",
)

Flag = stem.util.enum.Enum(
  ("AUTHORITY", "Authority"),
  ("BADEXIT", "BadExit"),
  ("BADDIRECTORY", "BadDirectory"),
  ("EXIT", "Exit"),
  ("FAST", "Fast"),
  ("GUARD", "Guard"),
  ("HSDIR", "HSDir"),
  ("NAMED", "Named"),
  ("RUNNING", "Running"),
  ("STABLE", "Stable"),
  ("UNNAMED", "Unnamed"),
  ("V2DIR", "V2Dir"),
  ("V3DIR", "V3Dir"),
  ("VALID", "Valid"),
)

Signal = stem.util.enum.UppercaseEnum(
  "RELOAD",
  "HUP",
  "SHUTDOWN",
  "INT",
  "DUMP",
  "USR1",
  "DEBUG",
  "USR2",
  "HALT",
  "TERM",
  "NEWNYM",
  "CLEARDNSCACHE",
)

CircStatus = stem.util.enum.UppercaseEnum(
  "LAUNCHED",
  "BUILT",
  "EXTENDED",
  "FAILED",
  "CLOSED",
)

CircBuildFlag = stem.util.enum.UppercaseEnum(
  "ONEHOP_TUNNEL",
  "IS_INTERNAL",
  "NEED_CAPACITY",
  "NEED_UPTIME",
)

CircPurpose = stem.util.enum.UppercaseEnum(
  "GENERAL",
  "HS_CLIENT_INTRO",
  "HS_CLIENT_REND",
  "HS_SERVICE_INTRO",
  "HS_SERVICE_REND",
  "TESTING",
  "CONTROLLER",
  "MEASURE_TIMEOUT",
)

CircClosureReason = stem.util.enum.UppercaseEnum(
  "NONE",
  "TORPROTOCOL",
  "INTERNAL",
  "REQUESTED",
  "HIBERNATING",
  "RESOURCELIMIT",
  "CONNECTFAILED",
  "OR_IDENTITY",
  "OR_CONN_CLOSED",
  "FINISHED",
  "TIMEOUT",
  "DESTROYED",
  "NOPATH",
  "NOSUCHSERVICE",
  "MEASUREMENT_EXPIRED",
)

CircEvent = stem.util.enum.UppercaseEnum(
  "PURPOSE_CHANGED",
  "CANNIBALIZED",
)

HiddenServiceState = stem.util.enum.UppercaseEnum(
  "HSCI_CONNECTING",
  "HSCI_INTRO_SENT",
  "HSCI_DONE",
  "HSCR_CONNECTING",
  "HSCR_ESTABLISHED_IDLE",
  "HSCR_ESTABLISHED_WAITING",
  "HSCR_JOINED",
  "HSSI_CONNECTING",
  "HSSI_ESTABLISHED",
  "HSSR_CONNECTING",
  "HSSR_JOINED",
)

RelayEndReason = stem.util.enum.UppercaseEnum(
  "MISC",
  "RESOLVEFAILED",
  "CONNECTREFUSED",
  "EXITPOLICY",
  "DESTROY",
  "DONE",
  "TIMEOUT",
  "NOROUTE",
  "HIBERNATING",
  "INTERNAL",
  "RESOURCELIMIT",
  "CONNRESET",
  "TORPROTOCOL",
  "NOTDIRECTORY",
)

StreamStatus = stem.util.enum.UppercaseEnum(
  "NEW",
  "NEWRESOLVE",
  "REMAP",
  "SENTCONNECT",
  "SENTRESOLVE",
  "SUCCEEDED",
  "FAILED",
  "DETACHED",
  "CLOSED",
)

# StreamClosureReason is a superset of RelayEndReason
StreamClosureReason = stem.util.enum.UppercaseEnum(*(RelayEndReason.keys() + [
  "END",
  "PRIVATE_ADDR",
]))

StreamSource = stem.util.enum.UppercaseEnum(
  "CACHE",
  "EXIT",
)

StreamPurpose = stem.util.enum.UppercaseEnum(
  "DIR_FETCH",
  "DIR_UPLOAD",
  "DNS_REQUEST",
  "DIRPORT_TEST",
  "USER",
)

ORStatus = stem.util.enum.UppercaseEnum(
  "NEW",
  "LAUNCHED",
  "CONNECTED",
  "FAILED",
  "CLOSED",
)

ORClosureReason = stem.util.enum.UppercaseEnum(
  "DONE",
  "CONNECTREFUSED",
  "IDENTITY",
  "CONNECTRESET",
  "TIMEOUT",
  "NOROUTE",
  "IOERROR",
  "RESOURCELIMIT",
  "MISC",
)

AuthDescriptorAction = stem.util.enum.UppercaseEnum(
  "ACCEPTED",
  "DROPPED",
  "REJECTED",
)

StatusType = stem.util.enum.UppercaseEnum(
  "GENERAL",
  "CLIENT",
  "SERVER",
)

GuardType = stem.util.enum.UppercaseEnum(
  "ENTRY",
)

GuardStatus = stem.util.enum.UppercaseEnum(
  "NEW",
  "UP",
  "DOWN",
  "BAD",
  "GOOD",
  "DROPPED",
)

TimeoutSetType = stem.util.enum.UppercaseEnum(
  "COMPUTED",
  "RESET",
  "SUSPENDED",
  "DISCARD",
  "RESUME",
)