Revised how we handle ClientTransportPlugin and Bridge lines.

Multiple Bridge lines can point to the same one ClientTransportPlugin
line, and we can have multiple ClientTransportPlugin lines in our
configuration file that don't match with a bridge. We also issue a
warning when we have a Bridge line with a pluggable transport but we
can't match it to a ClientTransportPlugin line.

1 files changed, 58 insertions, 19 deletions

diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index d5989f34c0..b1f967b7be 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -4607,16 +4607,15 @@ static transport_t *
 transport_get_by_name(const char *name)
 {
   tor_assert(name);
-  if (transport_list) {
-    SMARTLIST_FOREACH_BEGIN(transport_list, transport_t *, transport) {
-      if (!strcmp(transport->name, name))
-        return transport;
-    } SMARTLIST_FOREACH_END(transport);
-  }
 
-  log_notice(LD_GENERAL, "We were asked to match '%s' to a pluggable "
-             "transport, and we failed. If you didn't expect this, please "
-             "check your configuration.", name);
+  if (!transport_list)
+    return NULL;
+
+  SMARTLIST_FOREACH_BEGIN(transport_list, transport_t *, transport) {
+    if (!strcmp(transport->name, name))
+      return transport;
+  } SMARTLIST_FOREACH_END(transport);
+
   return NULL;
 }
 
@@ -4653,6 +4652,27 @@ transport_add_from_config(const tor_addr_t *addr, uint16_t port,
   return -1;
 }
 
+/** Warns the user of possible pluggable transport misconfiguration. */
+void
+validate_pluggable_transports_config(void)
+{
+  if (bridge_list) {
+    SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, b)
+      {
+        /* Skip bridges without transports. */
+        if (!b->transport_name)
+          continue;
+        /* See if the user has Bridges that specify nonexistent 
+           pluggable transports. We should warn the user in such case,
+           since it's probably misconfiguration. */
+        if (!transport_get_by_name(b->transport_name))
+          log_warn(LD_CONFIG, "You have a Bridge line using the %s "
+                   "pluggable transport, but there doesn't seem to be a "
+                   "corresponding ClientTransportPlugin line.", b->transport_name);
+      }  SMARTLIST_FOREACH_END(b);
+  }
+}
+
 /** Return a bridge pointer if <b>ri</b> is one of our known bridges
  * (either by comparing keys if possible, else by comparing addr/port).
  * Else return NULL. */
@@ -4789,24 +4809,41 @@ find_bridge_by_digest(const char *digest)
   return NULL;
 }
 
-/** If <b>addr</b> and <b>port</b> match one of our known bridges,
- *  returns its transport protocol if it has one, else returns NULL. */
-transport_t *
-find_transport_by_bridge_addrport(const tor_addr_t *addr, uint16_t port)
+/** If <b>addr</b> and <b>port</b> match the address and port of a
+ * bridge of ours that uses pluggable transports, place it's transport
+ * in <b>transport</b>.
+ *  
+ * Return:
+ * 0: if transport was found successfully.
+ * 1: if <b>addr</b>:<b>port</b> did not match a bridge,
+ *    or if matched bridge was not using transports.
+ * -1: if we should be using a transport, but the transport could not be found.
+ */
+int
+find_transport_by_bridge_addrport(const tor_addr_t *addr, uint16_t port, 
+                                  transport_t **transport)
 {
-  tor_assert(bridge_list);
+  if (!bridge_list)
+    return 1;
+
   SMARTLIST_FOREACH_BEGIN(bridge_list, bridge_info_t *, bridge)
     {
       if (tor_addr_eq(&bridge->addr, addr) &&
-          (bridge->port == port)) {
-        if (bridge->transport_name) {
-          return transport_get_by_name(bridge->transport_name);
-        } else /* bridge found, but it had no transport */
+          (bridge->port == port)) { /* bridge matched */
+        if (bridge->transport_name) { /* it also uses pluggable transports */
+          *transport = transport_get_by_name(bridge->transport_name);
+          if (*transport == NULL) { /* it uses pluggable transports, but
+                                       the transport could not be found! */
+            return -1;
+          }
+          return 0;
+        } else { /* bridge matched, but it doesn't use transports. */
           break;
+        }
       }
     } SMARTLIST_FOREACH_END(bridge);
 
-  return NULL;
+  return 1;
 }
 
 /** We need to ask <b>bridge</b> for its server descriptor. */
@@ -5116,6 +5153,8 @@ entry_guards_free_all(void)
   clear_bridge_list();
   clear_transport_list();
   smartlist_free(bridge_list);
+  smartlist_free(transport_list);
   bridge_list = NULL;
+  transport_list = NULL;
 }