Commit 6e923ed8 authored by Nick Mathewson's avatar Nick Mathewson 🤹
Browse files

Add an OptimisticData option to control client-side optimistic data

parent 9b0d3719

changes/optimistic-client

+4 −2
Original line number Diff line number Diff line
@@ -3,5 +3,7 @@ 
      clients can now "optimistically" send data on a stream before

      the exit node reports that the stream has opened. This can save

      a round trip when starting connections with protocols where the

      client speaks first.  Implements proposal 181; code by Ian

      Goldberg.
 
      client speaks first. This behavior is controlled by a (currently

      disabled) networkstatus consensus parameter. To turn it on or

      off manually, use the "OptimisticData" torrc option.  Implements

      proposal 181; code by Ian Goldberg.

doc/tor.1.txt

+10 −0
Original line number Diff line number Diff line
@@ -930,6 +930,16 @@ The following options are useful only for clients (that is, if 
    that have the **AllowSingleHopExits** option turned on to build

    one-hop Tor connections.  (Default: 0)



**OptimisticData** **0**|**1**|**auto**::

    When this option is set, and Tor is using an exit node that supports

    the feature, it will try optimistically to send data to the exit node

    without waiting for the exit node to report whether the connection

    succeeded.  This can save a round-trip time for protocols like HTTP

    where the client talks first.  If OptimisticData is set to **auto**,

    Tor will look at the UseOptimisticData parameter in the networkstatus.

    (Default: auto)





SERVER OPTIONS

--------------

src/or/circuituse.c

+16 −1
Original line number Diff line number Diff line
@@ -18,6 +18,7 @@ 
#include "connection_edge.h"

#include "control.h"

#include "nodelist.h"

#include "networkstatus.h"

#include "policies.h"

#include "rendclient.h"

#include "rendcommon.h"
@@ -1541,6 +1542,19 @@ cpath_is_on_circuit(origin_circuit_t *circ, crypt_path_t *crypt_path) 
  return 0;

}



/** Return true iff client-side optimistic data is supported. */

static int

optimistic_data_enabled(void)

{

  const or_options_t *options = get_options();

  if (options->OptimisticData < 0) {

    const int32_t enabled =

      networkstatus_get_param(NULL, "UseOptimisticData", 0, 0, 1);

    return (int)enabled;

  }

  return options->OptimisticData;

}



/** Attach the AP stream <b>apconn</b> to circ's linked list of

 * p_streams. Also set apconn's cpath_layer to <b>cpath</b>, or to the last

 * hop in circ's cpath if <b>cpath</b> is NULL.
@@ -1580,7 +1594,8 @@ link_apconn_to_circ(edge_connection_t *apconn, origin_circuit_t *circ, 
                     apconn->cpath_layer->extend_info->identity_digest)) &&

      exitnode->rs) {

    /* Okay; we know what exit node this is. */

    if (circ->_base.purpose == CIRCUIT_PURPOSE_C_GENERAL &&

    if (optimistic_data_enabled() &&

        circ->_base.purpose == CIRCUIT_PURPOSE_C_GENERAL &&

        exitnode->rs->version_supports_optimistic_data)

      apconn->exit_allows_optimistic_data = 1;

    else

src/or/config.c

+1 −0
Original line number Diff line number Diff line
@@ -337,6 +337,7 @@ static config_var_t _option_vars[] = { 
  V(PerConnBWRate,               MEMUNIT,  "0"),

  V(PidFile,                     STRING,   NULL),

  V(TestingTorNetwork,           BOOL,     "0"),

  V(OptimisticData,              AUTOBOOL, "auto"),

  V(PortForwarding,              BOOL,     "0"),

  V(PortForwardingHelper,        FILENAME, "tor-fw-helper"),

  V(PreferTunneledDirConns,      BOOL,     "1"),

src/or/or.h

+4 −0
Original line number Diff line number Diff line
@@ -3271,6 +3271,10 @@ typedef struct { 
   * once. */

  int MaxClientCircuitsPending;



  /** If 1, we always send optimistic data when it's supported.  If 0, we

   * never use it.  If -1, we do what the consensus says. */

  int OptimisticData;



} or_options_t;



/** Persistent state for an onion router, as saved to disk. */