Bug 7691: Send a probe cell down certain types of circs.

In general, if we tried to use a circ for a stream, but then decided to place
that stream on a different circuit, we need to probe the original circuit
before deciding it was a "success".

We also need to do the same for cannibalized circuits that go unused.

1 files changed, 11 insertions, 1 deletions

diff --git a/src/or/or.h b/src/or/or.h
index 7b8ff705a4..4b4806c62e 100644
--- a/src/or/or.h
+++ b/src/or/or.h
@@ -522,7 +522,9 @@ typedef enum {
 #define CIRCUIT_PURPOSE_TESTING 18
 /** A controller made this circuit and Tor should not use it. */
 #define CIRCUIT_PURPOSE_CONTROLLER 19
-#define CIRCUIT_PURPOSE_MAX_ 19
+/** This circuit is used for path bias probing only */
+#define CIRCUIT_PURPOSE_PATH_BIAS_TESTING 20
+#define CIRCUIT_PURPOSE_MAX_ 20
 /** A catch-all for unrecognized purposes. Currently we don't expect
  * to make or see any circuits with this purpose. */
 #define CIRCUIT_PURPOSE_UNKNOWN 255
@@ -2887,6 +2889,14 @@ typedef struct origin_circuit_t {
    * debug why we are not seeing first hops in some cases. */
   path_state_t path_state : 3;
 
+  /** For path probing. Store the temporary probe stream ID
+   * for response comparison */
+  streamid_t pathbias_probe_id;
+
+  /** For path probing. Store the temporary probe address nonce
+   * for response comparison. */
+  tor_addr_t pathbias_probe_nonce;
+
   /** Set iff this is a hidden-service circuit which has timed out
    * according to our current circuit-build timeout, but which has
    * been kept around because it might still succeed in connecting to