Retry circuits if the exit node is optional and nonexistant.

Previously, when we had the chosen_exit set but marked optional, and
we failed because we couldn't find an onion key for it, we'd just give
up on the circuit.  But what we really want to do is try again, without
the forced exit node.

Spotted by rovv.  Another case of bug 752.  I think this might be
unreachable in our current code, but proposal 158 could change that.

svn:r18451

1 files changed, 4 insertions, 1 deletions

diff --git a/src/or/circuituse.c b/src/or/circuituse.c
index 4bc6fcbe8..a1c8d1c14 100644
--- a/src/or/circuituse.c
+++ b/src/or/circuituse.c
@@ -1165,7 +1165,10 @@ circuit_get_open_circ_or_launch(edge_connection_t *conn,
             if (opt) {
               conn->chosen_exit_optional = 0;
               tor_free(conn->chosen_exit_name);
-              return 0;
+              /* Try again with no requested exit */
+              return circuit_get_open_circ_or_launch(conn,
+                                                     desired_circuit_purpose,
+                                                     circp);
             }
             return -1;
           }