make circ->onionskin a pointer, not a static array. moria2 was using

125000 circuit_t's after it had been up for a few weeks, which translates
to 20+ megs of wasted space.


svn:r5333

src/or/circuitbuild.c

@@ -414,10 +414,12 @@ circuit_n_conn_done(connection_t *or_conn, int status)
         }
       } else {
         /* pull the create cell out of circ->onionskin, and send it */
+        tor_assert(circ->onionskin);
         if (circuit_deliver_create_cell(circ,CELL_CREATE,circ->onionskin) < 0) {
           circuit_mark_for_close(circ);
           continue;
         }
+        tor_free(circ->onionskin);
       }
     }
   }
@@ -522,7 +524,7 @@ circuit_send_next_onion_skin(circuit_t *circ)
         return -1;
       }
     } else {
-      /* We are not an OR, and we building the first hop of a circuit to
+      /* We are not an OR, and we're building the first hop of a circuit to
        * a new OR: we can be speedy. */
       cell_type = CELL_CREATE_FAST;
       memset(payload, 0, sizeof(payload));
@@ -643,6 +645,7 @@ circuit_extend(cell_t *cell, circuit_t *circ)
     info(LD_CIRC|LD_OR,"Next router (%s:%d) not connected. Connecting.",
            tmpbuf, circ->n_port);
 
+    circ->onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
     memcpy(circ->onionskin, onionskin, ONIONSKIN_CHALLENGE_LEN);
     circ->state = CIRCUIT_STATE_OR_WAIT;
 
@@ -1197,6 +1200,8 @@ choose_good_exit_server_general(routerlist_t *dir, int need_uptime,
       smartlist_subtract(sl,excludedexits);
       if (options->StrictExitNodes || smartlist_overlap(sl,preferredexits))
         smartlist_intersect(sl,preferredexits);
+        /* XXX sometimes the above results in null, when the requested
+         * exit node is down. we should pick it anyway. */
       router = routerlist_sl_choose_by_bandwidth(sl);
       if (router)
         break;

src/or/circuitlist.c

@@ -250,6 +250,7 @@ circuit_free(circuit_t *circ)
       circuit_free_cpath_node(circ->build_state->pending_final_cpath);
   }
   tor_free(circ->build_state);
+  tor_free(circ->onionskin);
   circuit_free_cpath(circ->cpath);
   if (circ->rend_splice) {
     circ->rend_splice->rend_splice = NULL;
@@ -792,6 +793,7 @@ assert_circuit_ok(const circuit_t *c)
   tor_assert(c->deliver_window >= 0);
   tor_assert(c->package_window >= 0);
   if (c->state == CIRCUIT_STATE_OPEN) {
+    tor_assert(!c->onionskin);
     if (c->cpath) {
       tor_assert(CIRCUIT_IS_ORIGIN(c));
       tor_assert(!c->n_crypto);

src/or/command.c

@@ -200,6 +200,7 @@ command_process_create_cell(cell_t *cell, connection_t *conn)
   circ->purpose = CIRCUIT_PURPOSE_OR;
   circ->state = CIRCUIT_STATE_ONIONSKIN_PENDING;
   if (cell->command == CELL_CREATE) {
+    circ->onionskin = tor_malloc(ONIONSKIN_CHALLENGE_LEN);
     memcpy(circ->onionskin, cell->payload, ONIONSKIN_CHALLENGE_LEN);
 
     /* hand it off to the cpuworkers, and then return */

src/or/cpuworker.c

@@ -428,6 +428,7 @@ assign_to_cpuworker(connection_t *cpuworker, uint8_t question_type,
 
   if (question_type == CPUWORKER_TASK_ONION) {
     circ = task;
+    tor_assert(circ->onionskin);
 
     if (num_cpuworkers_busy == num_cpuworkers) {
       debug(LD_OR,"No idle cpuworkers. Queuing.");
@@ -453,6 +454,7 @@ assign_to_cpuworker(connection_t *cpuworker, uint8_t question_type,
     connection_write_to_buf((char*)&question_type, 1, cpuworker);
     connection_write_to_buf(tag, sizeof(tag), cpuworker);
     connection_write_to_buf(circ->onionskin, ONIONSKIN_CHALLENGE_LEN, cpuworker);
+    tor_free(circ->onionskin);
   }
   return 0;
 }

src/or/or.h

@@ -1068,8 +1068,11 @@ struct circuit_t {
    */
   crypt_path_t *cpath;
 
-  /** For storage while passing to cpuworker, or while n_conn is pending. */
-  char onionskin[ONIONSKIN_CHALLENGE_LEN];
+  /** For storage while passing to cpuworker (state
+    * CIRCUIT_STATE_ONIONSKIN_PENDING), or while n_conn is pending
+    * (state CIRCUIT_STATE_OR_WAIT). When defined, it is always
+    * length ONIONSKIN_CHALLENGE_LEN. */
+  char *onionskin;
 
   char handshake_digest[DIGEST_LEN]; /**< Stores KH for intermediate hops. */