make some bug 1090 warnings go away

When we excluded some Exits, we were sometimes warning the user that we
were going to use the node regardless. Many of those warnings were in
fact bogus, because the relay in question was not used to connect to
the outside world.

Based on patch by Rotor, thanks!

ChangeLog

@@ -33,6 +33,10 @@ Changes in version 0.2.1.20 - 2009-??-??
       controller when we want to inform the user of overall success or
       overall failure. Bugfix on 0.1.2.6-alpha. Fixes bug 1075. Reported
       by SwissTorExit.
+    - Don't warn when we're using a circuit that ends with a node
+      excluded in ExcludeExitNodes, but the circuit is not used to access
+      the outside world. This should help fix bug 1090. Bugfix on
+      0.2.1.6-alpha.
 
   o Minor features:
     - Add a "getinfo status/accepted-server-descriptor" controller

src/or/circuitbuild.c

@@ -1444,13 +1444,16 @@ choose_good_exit_server(uint8_t purpose, routerlist_t *dir,
 /** Log a warning if the user specified an exit for the circuit that
  * has been excluded from use by ExcludeNodes or ExcludeExitNodes. */
 static void
-warn_if_last_router_excluded(uint8_t purpose, const extend_info_t *exit)
+warn_if_last_router_excluded(origin_circuit_t *circ, const extend_info_t *exit)
 {
   or_options_t *options = get_options();
   routerset_t *rs = options->ExcludeNodes;
   const char *description;
-  int severity;
   int domain = LD_CIRC;
+  uint8_t purpose = circ->_base.purpose;
+
+  if (circ->build_state->onehop_tunnel)
+    return;
 
   switch (purpose)
     {
@@ -1463,48 +1466,40 @@ warn_if_last_router_excluded(uint8_t purpose, const extend_info_t *exit)
                (int)purpose);
       return;
     case CIRCUIT_PURPOSE_C_GENERAL:
+      if (circ->build_state->is_internal)
+        return;
       description = "Requested exit node";
       rs = options->_ExcludeExitNodesUnion;
-      severity = LOG_WARN;
       break;
     case CIRCUIT_PURPOSE_C_INTRODUCING:
     case CIRCUIT_PURPOSE_C_INTRODUCE_ACK_WAIT:
     case CIRCUIT_PURPOSE_C_INTRODUCE_ACKED:
-      description = "Introduction point for hidden service";
+    case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
-      severity = LOG_INFO;
+    case CIRCUIT_PURPOSE_S_CONNECT_REND:
-      break;
+    case CIRCUIT_PURPOSE_S_REND_JOINED:
+    case CIRCUIT_PURPOSE_TESTING:
+      return;
     case CIRCUIT_PURPOSE_C_ESTABLISH_REND:
     case CIRCUIT_PURPOSE_C_REND_READY:
     case CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED:
     case CIRCUIT_PURPOSE_C_REND_JOINED:
       description = "Chosen rendezvous point";
-      severity = LOG_WARN;
       domain = LD_BUG;
       break;
-    case CIRCUIT_PURPOSE_S_ESTABLISH_INTRO:
-      description = "Chosen introduction point";
-      severity = LOG_INFO;
-      break;
-    case CIRCUIT_PURPOSE_S_CONNECT_REND:
-    case CIRCUIT_PURPOSE_S_REND_JOINED:
-      description = "Client-selected rendezvous point";
-      severity = LOG_INFO;
-      break;
-    case CIRCUIT_PURPOSE_TESTING:
-      description = "Target for testing circuit";
-      severity = LOG_INFO;
-      break;
     case CIRCUIT_PURPOSE_CONTROLLER:
       rs = options->_ExcludeExitNodesUnion;
       description = "Controller-selected circuit target";
-      severity = LOG_WARN;
       break;
     }
 
-  if (routerset_contains_extendinfo(rs, exit))
+  if (routerset_contains_extendinfo(rs, exit)) {
-    log_fn(severity, domain, "%s '%s' is in ExcludeNodes%s.  Using anyway.",
+    log_fn(LOG_WARN, domain, "%s '%s' is in ExcludeNodes%s. Using anyway "
+           "(circuit purpose %d).",
            description,exit->nickname,
-           rs==options->ExcludeNodes?"":" or ExcludeExitNodes.");
+           rs==options->ExcludeNodes?"":" or ExcludeExitNodes",
+           (int)purpose);
+    circuit_log_path(LOG_WARN, domain, circ);
+  }
 
   return;
 }
@@ -1529,7 +1524,7 @@ onion_pick_cpath_exit(origin_circuit_t *circ, extend_info_t *exit)
   }
 
   if (exit) { /* the circuit-builder pre-requested one */
-    warn_if_last_router_excluded(circ->_base.purpose, exit);
+    warn_if_last_router_excluded(circ, exit);
     log_info(LD_CIRC,"Using requested exit node '%s'", exit->nickname);
     exit = extend_info_dup(exit);
   } else { /* we have to decide one */
@@ -1576,6 +1571,7 @@ int
 circuit_extend_to_new_exit(origin_circuit_t *circ, extend_info_t *exit)
 {
   int err_reason = 0;
+  warn_if_last_router_excluded(circ, exit);
   circuit_append_new_exit(circ, exit);
   circuit_set_state(TO_CIRCUIT(circ), CIRCUIT_STATE_BUILDING);
   if ((err_reason = circuit_send_next_onion_skin(circ))<0) {