-hopefully fixing #2390
[oweals/gnunet.git] / src / util / server.c
index c0b62374ea987aa725ab7b7620e343382b939f3e..b1edf2c455658fcbd1b18e4e818cd16ac3a1fba0 100644 (file)
@@ -91,9 +91,14 @@ struct GNUNET_SERVER_Handle
   struct HandlerList *handlers;
 
   /**
-   * List of our current clients.
+   * Head of list of our current clients.
    */
-  struct GNUNET_SERVER_Client *clients;
+  struct GNUNET_SERVER_Client *clients_head;
+
+  /**
+   * Head of list of our current clients.
+   */
+  struct GNUNET_SERVER_Client *clients_tail;
 
   /**
    * Head of linked list of functions to call on disconnects by clients.
@@ -199,10 +204,15 @@ struct GNUNET_SERVER_Client
 {
 
   /**
-   * This is a linked list.
+   * This is a doubly linked list.
    */
   struct GNUNET_SERVER_Client *next;
 
+  /**
+   * This is a doubly linked list.
+   */
+  struct GNUNET_SERVER_Client *prev;
+
   /**
    * Processing of incoming data.
    */
@@ -276,8 +286,7 @@ struct GNUNET_SERVER_Client
   int in_process_client_buffer;
 
   /**
-   * We're about to close down this client due to some serious
-   * error.
+   * We're about to close down this client.
    */
   int shutdown_now;
 
@@ -321,27 +330,66 @@ struct GNUNET_SERVER_Client
  * @param tc reason why we are running right now
  */
 static void
-process_listen_socket (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+process_listen_socket (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc);
+
+
+/**
+ * Add a listen task with the scheduler for this server.
+ *
+ * @param server handle to our server for which we are adding the listen
+ *        socket
+ */
+static void
+schedule_listen_task (struct GNUNET_SERVER_Handle *server)
 {
-  struct GNUNET_SERVER_Handle *server = cls;
-  struct GNUNET_CONNECTION_Handle *sock;
-  struct GNUNET_SERVER_Client *client;
   struct GNUNET_NETWORK_FDSet *r;
   unsigned int i;
 
-  server->listen_task = GNUNET_SCHEDULER_NO_TASK;
+  if (NULL == server->listen_sockets[0])
+    return; /* nothing to do, no listen sockets! */
+  if (NULL == server->listen_sockets[1])
+  {
+    /* simplified method: no fd set needed; this is then much simpler and
+       much more efficient */
+    server->listen_task =
+      GNUNET_SCHEDULER_add_read_net_with_priority (GNUNET_TIME_UNIT_FOREVER_REL,
+                                                  GNUNET_SCHEDULER_PRIORITY_HIGH,
+                                                  server->listen_sockets[0],
+                                                  &process_listen_socket, server);
+    return;
+  }
   r = GNUNET_NETWORK_fdset_create ();
   i = 0;
   while (NULL != server->listen_sockets[i])
     GNUNET_NETWORK_fdset_set (r, server->listen_sockets[i++]);
+  server->listen_task =
+    GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
+                                GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
+                                &process_listen_socket, server);
+  GNUNET_NETWORK_fdset_destroy (r);
+}
+
+
+/**
+ * Scheduler says our listen socket is ready.  Process it!
+ *
+ * @param cls handle to our server for which we are processing the listen
+ *        socket
+ * @param tc reason why we are running right now
+ */
+static void
+process_listen_socket (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_SERVER_Handle *server = cls;
+  struct GNUNET_CONNECTION_Handle *sock;
+  struct GNUNET_SERVER_Client *client;
+  unsigned int i;
+
+  server->listen_task = GNUNET_SCHEDULER_NO_TASK;
   if (0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN))
   {
     /* ignore shutdown, someone else will take care of it! */
-    server->listen_task =
-        GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
-                                     GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
-                                     &process_listen_socket, server);
-    GNUNET_NETWORK_fdset_destroy (r);
+    schedule_listen_task (server);
     return;
   }
   i = 0;
@@ -364,11 +412,7 @@ process_listen_socket (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
     i++;
   }
   /* listen for more! */
-  server->listen_task =
-      GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
-                                   GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
-                                   &process_listen_socket, server);
-  GNUNET_NETWORK_fdset_destroy (r);
+  schedule_listen_task (server);
 }
 
 
@@ -382,7 +426,7 @@ process_listen_socket (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 static struct GNUNET_NETWORK_Handle *
 open_listen_socket (const struct sockaddr *serverAddr, socklen_t socklen)
 {
-  const static int on = 1;
+  static int on = 1;
   struct GNUNET_NETWORK_Handle *sock;
   uint16_t port;
   int eno;
@@ -492,8 +536,6 @@ GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access,
                                    int require_found)
 {
   struct GNUNET_SERVER_Handle *server;
-  struct GNUNET_NETWORK_FDSet *r;
-  int i;
 
   server = GNUNET_malloc (sizeof (struct GNUNET_SERVER_Handle));
   server->idle_timeout = idle_timeout;
@@ -502,17 +544,7 @@ GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access,
   server->access_cls = access_cls;
   server->require_found = require_found;
   if (NULL != lsocks)
-  {
-    r = GNUNET_NETWORK_fdset_create ();
-    i = 0;
-    while (NULL != server->listen_sockets[i])
-      GNUNET_NETWORK_fdset_set (r, server->listen_sockets[i++]);
-    server->listen_task =
-        GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
-                                     GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
-                                     &process_listen_socket, server);
-    GNUNET_NETWORK_fdset_destroy (r);
-  }
+    schedule_listen_task (server);
   return server;
 }
 
@@ -637,7 +669,7 @@ test_monitor_clients (struct GNUNET_SERVER_Handle *server)
 
   if (GNUNET_YES != server->in_soft_shutdown)
     return;
-  for (client = server->clients; NULL != client; client = client->next)
+  for (client = server->clients_head; NULL != client; client = client->next)
     if (GNUNET_NO == client->is_monitor)
       return; /* not done yet */
   server->in_soft_shutdown = GNUNET_SYSERR;
@@ -705,8 +737,8 @@ GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *server)
     GNUNET_free (server->listen_sockets);
     server->listen_sockets = NULL;
   }
-  while (NULL != server->clients)
-    GNUNET_SERVER_client_disconnect (server->clients);
+  while (NULL != server->clients_head)
+    GNUNET_SERVER_client_disconnect (server->clients_head);
   while (NULL != (hpos = server->handlers))
   {
     server->handlers = hpos->next;
@@ -785,6 +817,7 @@ warn_no_receive_done (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   struct GNUNET_SERVER_Client *client = cls;
 
+  GNUNET_break (0 != client->warn_type); /* type should never be 0 here, as we don't use 0 */
   client->warn_task =
       GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
                                     &warn_no_receive_done, client);
@@ -869,9 +902,11 @@ GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
         }
         if (NULL != sender)
         {
-          if (0 == sender->suspended)
+          if ( (0 == sender->suspended) &&
+              (GNUNET_SCHEDULER_NO_TASK == sender->warn_task) )
           {
-            sender->warn_start = GNUNET_TIME_absolute_get ();
+           GNUNET_break (0 != type); /* type should never be 0 here, as we don't use 0 */
+            sender->warn_start = GNUNET_TIME_absolute_get ();      
             sender->warn_task =
                 GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
                                               &warn_no_receive_done, sender);
@@ -964,7 +999,6 @@ process_mst (struct GNUNET_SERVER_Client *client, int ret)
   }
   if ((GNUNET_SYSERR == ret) || (GNUNET_YES == client->shutdown_now))
     GNUNET_SERVER_client_disconnect (client);
-  GNUNET_SERVER_client_drop (client);
 }
 
 
@@ -1026,11 +1060,20 @@ process_incoming (void *cls, const void *buf, size_t available,
     ret =
         client->server->mst_receive (client->server->mst_cls, client->mst,
                                      client, buf, available, GNUNET_NO, GNUNET_YES);
-  else
+  else if (NULL != client->mst)
+  {
     ret =
         GNUNET_SERVER_mst_receive (client->mst, client, buf, available, GNUNET_NO,
                                    GNUNET_YES);
+  }
+  else
+  {
+    GNUNET_break (0);
+    return;
+  }
+
   process_mst (client, ret);
+  GNUNET_SERVER_client_drop (client);
 }
 
 
@@ -1046,6 +1089,7 @@ restart_processing (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
 {
   struct GNUNET_SERVER_Client *client = cls;
 
+  GNUNET_assert (GNUNET_YES != client->shutdown_now);
   client->restart_task = GNUNET_SCHEDULER_NO_TASK;
   if (GNUNET_NO == client->receive_pending)
   {
@@ -1061,6 +1105,7 @@ restart_processing (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
   GNUNET_SERVER_client_keep (client);
   client->receive_pending = GNUNET_NO;
   process_mst (client, GNUNET_NO);
+  GNUNET_SERVER_client_drop (client);
 }
 
 
@@ -1071,8 +1116,10 @@ restart_processing (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
  * @param cls closure (struct GNUNET_SERVER_Handle)
  * @param client identification of the client (struct GNUNET_SERVER_Client*)
  * @param message the actual message
+ *
+ * @return GNUNET_OK on success, GNUNET_SYSERR to stop further processing
  */
-static void
+static int
 client_message_tokenizer_callback (void *cls, void *client,
                                    const struct GNUNET_MessageHeader *message)
 {
@@ -1086,8 +1133,12 @@ client_message_tokenizer_callback (void *cls, void *client,
   sender->in_process_client_buffer = GNUNET_YES;
   ret = GNUNET_SERVER_inject (server, sender, message);
   sender->in_process_client_buffer = GNUNET_NO;
-  if (GNUNET_OK != ret)
+  if ( (GNUNET_OK != ret) || (GNUNET_YES == sender->shutdown_now) )
+  {
     GNUNET_SERVER_client_disconnect (sender);
+    return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
 }
 
 
@@ -1114,15 +1165,17 @@ GNUNET_SERVER_connect_socket (struct GNUNET_SERVER_Handle *server,
   client->reference_count = 1;
   client->server = server;
   client->last_activity = GNUNET_TIME_absolute_get ();
-  client->next = server->clients;
   client->idle_timeout = server->idle_timeout;
-  server->clients = client;
+  GNUNET_CONTAINER_DLL_insert (server->clients_head,
+                              server->clients_tail,
+                              client);
   if (NULL != server->mst_create)
     client->mst =
         server->mst_create (server->mst_cls, client);
   else
     client->mst =
         GNUNET_SERVER_mst_create (&client_message_tokenizer_callback, server);
+  GNUNET_assert (NULL != client->mst);
   client->receive_pending = GNUNET_YES;
   GNUNET_CONNECTION_receive (client->connection,
                              GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
@@ -1250,6 +1303,25 @@ GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
 }
 
 
+/**
+ * Destroy the connection that is passed in via 'cls'.  Used
+ * as calling 'GNUNET_CONNECTION_destroy' from within a function
+ * that was itself called from within 'process_notify' of
+ * 'connection.c' is not allowed (see #2329).
+ *
+ * @param cls connection to destroy
+ * @param tc scheduler context (unused)
+ */
+static void
+destroy_connection (void *cls,
+                   const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_CONNECTION_Handle *connection = cls;
+  
+  GNUNET_CONNECTION_destroy (connection);
+}
+
+
 /**
  * Ask the server to disconnect from the given client.
  * This is the same as returning GNUNET_SYSERR from a message
@@ -1262,10 +1334,7 @@ void
 GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client)
 {
   struct GNUNET_SERVER_Handle *server = client->server;
-  struct GNUNET_SERVER_Client *prev;
-  struct GNUNET_SERVER_Client *pos;
   struct NotifyList *n;
-  unsigned int rc;
 
   LOG (GNUNET_ERROR_TYPE_DEBUG,
        "Client is being disconnected from the server.\n");
@@ -1284,44 +1353,24 @@ GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client)
     GNUNET_CONNECTION_receive_cancel (client->connection);
     client->receive_pending = GNUNET_NO;
   }
-  rc = client->reference_count;
+  client->shutdown_now = GNUNET_YES;    
   client->reference_count++; /* make sure nobody else clean up client... */
-  if ( (GNUNET_YES != client->shutdown_now) &&
+  if ( (NULL != client->mst) &&
        (NULL != server) )
   {
-    client->shutdown_now = GNUNET_YES;
-    prev = NULL;
-    pos = server->clients;
-    while ((NULL != pos) && (pos != client))
-    {
-      prev = pos;
-      pos = pos->next;
-    }
-    GNUNET_assert (NULL != pos);
-    if (NULL == prev)
-      server->clients = pos->next;
-    else
-      prev->next = pos->next;
-    if (GNUNET_SCHEDULER_NO_TASK != client->restart_task)
-    {
-      GNUNET_SCHEDULER_cancel (client->restart_task);
-      client->restart_task = GNUNET_SCHEDULER_NO_TASK;
-    }
-    if (GNUNET_SCHEDULER_NO_TASK != client->warn_task)
-    {
-      GNUNET_SCHEDULER_cancel (client->warn_task);
-      client->warn_task = GNUNET_SCHEDULER_NO_TASK;
-    }
-    for (n = server->disconnect_notify_list_head; NULL != n; n = n->next)
-      n->callback (n->callback_cls, client);
+    GNUNET_CONTAINER_DLL_remove (server->clients_head,
+                                server->clients_tail,
+                                client);
     if (NULL != server->mst_destroy)
       server->mst_destroy (server->mst_cls, client->mst);
     else
       GNUNET_SERVER_mst_destroy (client->mst);
     client->mst = NULL;
+    for (n = server->disconnect_notify_list_head; NULL != n; n = n->next)
+      n->callback (n->callback_cls, client);
   }
   client->reference_count--;
-  if (rc > 0)
+  if (client->reference_count > 0)
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "RC still positive, not destroying everything.\n");
@@ -1338,7 +1387,16 @@ GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client)
     GNUNET_CONNECTION_persist_ (client->connection);
   if (NULL != client->th.cth)
     GNUNET_SERVER_notify_transmit_ready_cancel (&client->th);
-  GNUNET_CONNECTION_destroy (client->connection);
+  (void) GNUNET_SCHEDULER_add_now (&destroy_connection,
+                                  client->connection);
+  /* need to cancel again, as it might have been re-added
+     in the meantime (i.e. during callbacks) */
+  if (GNUNET_SCHEDULER_NO_TASK != client->warn_task)
+  {
+    GNUNET_SCHEDULER_cancel (client->warn_task);
+    client->warn_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  GNUNET_assert (GNUNET_NO == client->receive_pending);
   GNUNET_free (client);
   /* we might be in soft-shutdown, test if we're done */
   if (NULL != server)
@@ -1375,14 +1433,12 @@ transmit_ready_callback_wrapper (void *cls, size_t size, void *buf)
 {
   struct GNUNET_SERVER_Client *client = cls;
   GNUNET_CONNECTION_TransmitReadyNotify callback;
-  size_t ret;
 
   client->th.cth = NULL;
   callback = client->th.callback;
   client->th.callback = NULL;
   client->last_activity = GNUNET_TIME_absolute_get ();
-  ret = callback (client->th.callback_cls, size, buf);
-  return ret;
+  return callback (client->th.callback_cls, size, buf);
 }
 
 
@@ -1470,7 +1526,10 @@ GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success)
   {
     LOG (GNUNET_ERROR_TYPE_DEBUG,
          "GNUNET_SERVER_receive_done called with failure indication\n");
-    GNUNET_SERVER_client_disconnect (client);
+    if ( (client->reference_count > 0) || (client->suspended > 0) )
+      client->shutdown_now = GNUNET_YES;
+    else
+      GNUNET_SERVER_client_disconnect (client);
     return;
   }
   if (client->suspended > 0)