Fix Reachability self-tests in test networks

Stop assuming that private addresses are local when checking
reachability in a TestingTorNetwork. Instead, when testing, assume
all OR connections are remote. (This is necessary due to many test
scenarios running all nodes on localhost.)

This assists in bootstrapping a testing Tor network.

Fixes bugs 13718 & 13924.

changes/bug13924-fix-testing-reachability

@@ -0,0 +1,7 @@
+  o Minor bugfixes:
+    - Stop assuming that private addresses are local when checking
+      reachability in a TestingTorNetwork. Instead, when testing, assume
+      all OR connections are remote. (This is necessary due to many test
+      scenarios running all nodes on localhost.)
+      This assists in bootstrapping a testing Tor network.
+      Fixes bugs 13718 & 13924.

src/or/circuitbuild.c

@@ -1378,8 +1378,10 @@ onionskin_answer(or_circuit_t *circ,
   log_debug(LD_CIRC,"Finished sending '%s' cell.",
             circ->is_first_hop ? "created_fast" : "created");
 
-  if (!channel_is_local(circ->p_chan) &&
-      !channel_is_outgoing(circ->p_chan)) {
+  /* Ignore the local bit when testing - many test networks run on local
+   * addresses */
+  if ((!channel_is_local(circ->p_chan) || get_options()->TestingTorNetwork)
+      && !channel_is_outgoing(circ->p_chan)) {
     /* record that we could process create cells from a non-local conn
      * that we didn't initiate; presumably this means that create cells
      * can reach us too. */