Make OptimisticData always-on.

We've been using it for years, and it seems to work just fine.  This
patch removes the option and its network parameter.

Part of #40139

doc/man/tor.1.txt

@@ -1314,15 +1314,6 @@ The following options are useful only for clients (that is, if
     Every NUM seconds consider whether to build a new circuit. (Default: 30
     seconds)
 
-[[OptimisticData]] **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)
-
 // These are out of order because they logically belong together
 [[PathBiasCircThreshold]] **PathBiasCircThreshold** __NUM__ +
 

src/app/config/config.c

@@ -610,7 +610,7 @@ static const config_var_t option_vars_[] = {
   V(TestingAuthKeySlop,              INTERVAL, "3 hours"),
   V(TestingSigningKeySlop,           INTERVAL, "1 day"),
 
-  V(OptimisticData,              AUTOBOOL, "auto"),
+  OBSOLETE("OptimisticData"),
   OBSOLETE("PortForwarding"),
   OBSOLETE("PortForwardingHelper"),
   OBSOLETE("PreferTunneledDirConns"),

src/app/config/or_options_st.h

@@ -869,10 +869,6 @@ struct or_options_t {
    * 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;
-
   /** If 1, we accept and launch no external network connections, except on
    * control ports. */
   int DisableNetwork;

src/core/or/circuituse.c

@@ -2632,22 +2632,6 @@ 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) {
-    /* Note: this default was 0 before #18815 was merged. We can't take the
-     * parameter out of the consensus until versions before that are all
-     * obsolete. */
-    const int32_t enabled =
-      networkstatus_get_param(NULL, "UseOptimisticData", /*default*/ 1, 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.
@@ -2700,11 +2684,10 @@ link_apconn_to_circ(entry_connection_t *apconn, origin_circuit_t *circ,
     exitnode = node_get_by_id(cpath->extend_info->identity_digest);
 
   /* See if we can use optimistic data on this circuit */
-  if (optimistic_data_enabled() &&
-      (circ->base_.purpose == CIRCUIT_PURPOSE_C_GENERAL ||
+  if (circ->base_.purpose == CIRCUIT_PURPOSE_C_GENERAL ||
       circ->base_.purpose == CIRCUIT_PURPOSE_C_HSDIR_GET ||
       circ->base_.purpose == CIRCUIT_PURPOSE_S_HSDIR_POST ||
-       circ->base_.purpose == CIRCUIT_PURPOSE_C_REND_JOINED))
+      circ->base_.purpose == CIRCUIT_PURPOSE_C_REND_JOINED)
     apconn->may_use_optimistic_data = 1;
   else
     apconn->may_use_optimistic_data = 0;

src/test/conf_examples/large_1/expected

@@ -111,7 +111,6 @@ NumDirectoryGuards 4
 NumEntryGuards 5
 NumPrimaryGuards 8
 OfflineMasterKey 1
-OptimisticData 1
 ORPort 2222
 OutboundBindAddress 10.0.0.7
 OutboundBindAddressExit 10.0.0.8

src/test/conf_examples/large_1/expected_no_dirauth

@@ -110,7 +110,6 @@ NumDirectoryGuards 4
 NumEntryGuards 5
 NumPrimaryGuards 8
 OfflineMasterKey 1
-OptimisticData 1
 ORPort 2222
 OutboundBindAddress 10.0.0.7
 OutboundBindAddressExit 10.0.0.8