Try to diagnose bug 12184

Check for consistency between the queued destroy cells and the marked
circuit IDs.  Check for consistency in the count of queued destroy
cells in several ways.  Check to see whether any of the marked circuit
IDs have somehow been marked longer than the channel has existed.

1 files changed, 28 insertions, 1 deletions

diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index 6238e08e1e..ba16bb1457 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -59,6 +59,8 @@ typedef struct chan_circid_circuit_map_t {
   channel_t *chan;
   circid_t circ_id;
   circuit_t *circuit;
+  /* For debugging 12184: when was this placeholder item added? */
+  time_t made_placeholder_at;
 } chan_circid_circuit_map_t;
 
 /** Helper for hash tables: compare the channel and circuit ID for a and
@@ -184,6 +186,7 @@ circuit_set_circid_chan_helper(circuit_t *circ, int direction,
   found = HT_FIND(chan_circid_map, &chan_circid_map, &search);
   if (found) {
     found->circuit = circ;
+    found->made_placeholder_at = 0;
   } else {
     found = tor_malloc_zero(sizeof(chan_circid_circuit_map_t));
     found->circ_id = id;
@@ -241,11 +244,14 @@ channel_mark_circid_unusable(channel_t *chan, circid_t id)
              "a circuit there.", (unsigned)id, chan);
   } else if (ent) {
     /* It's already marked. */
+    if (!ent->made_placeholder_at)
+      ent->made_placeholder_at = approx_time();
   } else {
     ent = tor_malloc_zero(sizeof(chan_circid_circuit_map_t));
     ent->chan = chan;
     ent->circ_id = id;
-    /* leave circuit at NULL */
+    /* leave circuit at NULL. */
+    ent->made_placeholder_at = approx_time();
     HT_INSERT(chan_circid_map, &chan_circid_map, ent);
   }
 }
@@ -1090,6 +1096,27 @@ circuit_id_in_use_on_channel(circid_t circ_id, channel_t *chan)
   return 0;
 }
 
+/** Helper for debugging 12184.  Returns the time since which 'circ_id' has
+ * been marked unusable on 'chan'. */
+time_t
+circuit_id_when_marked_unusable_on_channel(circid_t circ_id, channel_t *chan)
+{
+  chan_circid_circuit_map_t search;
+  chan_circid_circuit_map_t *found;
+
+  memset(&search, 0, sizeof(search));
+  search.circ_id = circ_id;
+  search.chan = chan;
+
+  found = HT_FIND(chan_circid_map, &chan_circid_map, &search);
+
+  if (! found || found->circuit)
+    return 0;
+
+  return found->made_placeholder_at;
+}
+
+
 /** Return the circuit that a given edge connection is using. */
 circuit_t *
 circuit_get_by_edge_conn(edge_connection_t *conn)