Imported Upstream version 0.9.2upstream/0.9.2

1 files changed, 1415 insertions, 0 deletions

diff --git a/src/util/server.c b/src/util/server.c
new file mode 100644
index 0000000..24804d2
--- /dev/null
+++ b/src/util/server.c
@@ -0,0 +1,1415 @@
+/*
+     This file is part of GNUnet.
+     (C) 2009 Christian Grothoff (and other contributing authors)
+
+     GNUnet is free software; you can redistribute it and/or modify
+     it under the terms of the GNU General Public License as published
+     by the Free Software Foundation; either version 2, or (at your
+     option) any later version.
+
+     GNUnet is distributed in the hope that it will be useful, but
+     WITHOUT ANY WARRANTY; without even the implied warranty of
+     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+     General Public License for more details.
+
+     You should have received a copy of the GNU General Public License
+     along with GNUnet; see the file COPYING.  If not, write to the
+     Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+     Boston, MA 02111-1307, USA.
+*/
+
+/**
+ * @file util/server.c
+ * @brief library for building GNUnet network servers
+ * @author Christian Grothoff
+ */
+
+#include "platform.h"
+#include "gnunet_common.h"
+#include "gnunet_connection_lib.h"
+#include "gnunet_scheduler_lib.h"
+#include "gnunet_server_lib.h"
+#include "gnunet_time_lib.h"
+#include "gnunet_disk_lib.h"
+#include "gnunet_protocols.h"
+
+#define LOG(kind,...) GNUNET_log_from (kind, "util", __VA_ARGS__)
+
+#define LOG_STRERROR(kind,syscall) GNUNET_log_from_strerror (kind, "util", syscall)
+
+#define LOG_STRERROR_FILE(kind,syscall,filename) GNUNET_log_from_strerror_file (kind, "util", syscall, filename)
+
+#define DEBUG_SERVER GNUNET_EXTRA_LOGGING
+
+/**
+ * List of arrays of message handlers.
+ */
+struct HandlerList
+{
+  /**
+   * This is a linked list.
+   */
+  struct HandlerList *next;
+
+  /**
+   * NULL-terminated array of handlers.
+   */
+  const struct GNUNET_SERVER_MessageHandler *handlers;
+};
+
+
+/**
+ * List of arrays of message handlers.
+ */
+struct NotifyList
+{
+  /**
+   * This is a linked list.
+   */
+  struct NotifyList *next;
+
+  /**
+   * Function to call.
+   */
+  GNUNET_SERVER_DisconnectCallback callback;
+
+  /**
+   * Closure for callback.
+   */
+  void *callback_cls;
+};
+
+
+/**
+ * @brief handle for a server
+ */
+struct GNUNET_SERVER_Handle
+{
+  /**
+   * List of handlers for incoming messages.
+   */
+  struct HandlerList *handlers;
+
+  /**
+   * List of our current clients.
+   */
+  struct GNUNET_SERVER_Client *clients;
+
+  /**
+   * Linked list of functions to call on disconnects by clients.
+   */
+  struct NotifyList *disconnect_notify_list;
+
+  /**
+   * Function to call for access control.
+   */
+  GNUNET_CONNECTION_AccessCheck access;
+
+  /**
+   * Closure for access.
+   */
+  void *access_cls;
+
+  /**
+   * NULL-terminated array of sockets used to listen for new
+   * connections.
+   */
+  struct GNUNET_NETWORK_Handle **listen_sockets;
+
+  /**
+   * After how long should an idle connection time
+   * out (on write).
+   */
+  struct GNUNET_TIME_Relative idle_timeout;
+
+  /**
+   * Task scheduled to do the listening.
+   */
+  GNUNET_SCHEDULER_TaskIdentifier listen_task;
+
+  /**
+   * Do we ignore messages of types that we do not understand or do we
+   * require that a handler is found (and if not kill the connection)?
+   */
+  int require_found;
+
+  /**
+   * Should all of the clients of this server continue to process
+   * connections as usual even if we get a shutdown request? (the
+   * listen socket always ignores shutdown).
+   */
+  int clients_ignore_shutdown;
+
+  GNUNET_SERVER_MstCreateCallback mst_create;
+  GNUNET_SERVER_MstDestroyCallback mst_destroy;
+  GNUNET_SERVER_MstReceiveCallback mst_receive;
+  void *mst_cls;
+};
+
+
+/**
+ * @brief handle for a client of the server
+ */
+struct GNUNET_SERVER_Client
+{
+
+  /**
+   * This is a linked list.
+   */
+  struct GNUNET_SERVER_Client *next;
+
+  /**
+   * Processing of incoming data.
+   */
+  void *mst;
+
+  /**
+   * Server that this client belongs to.
+   */
+  struct GNUNET_SERVER_Handle *server;
+
+  /**
+   * Client closure for callbacks.
+   */
+  struct GNUNET_CONNECTION_Handle *connection;
+
+  /**
+   * ID of task used to restart processing.
+   */
+  GNUNET_SCHEDULER_TaskIdentifier restart_task;
+
+  /**
+   * Task that warns about missing calls to 'GNUNET_SERVER_receive_done'.
+   */
+  GNUNET_SCHEDULER_TaskIdentifier warn_task;
+
+  /**
+   * Time when the warn task was started.
+   */
+  struct GNUNET_TIME_Absolute warn_start;
+
+  /**
+   * Last activity on this socket (used to time it out
+   * if reference_count == 0).
+   */
+  struct GNUNET_TIME_Absolute last_activity;
+
+  /**
+   *
+   */
+  GNUNET_CONNECTION_TransmitReadyNotify callback;
+
+  /**
+   * callback
+   */
+  void *callback_cls;
+
+  /**
+   * After how long should an idle connection time
+   * out (on write).
+   */
+  struct GNUNET_TIME_Relative idle_timeout;
+
+  /**
+   * Number of external entities with a reference to
+   * this client object.
+   */
+  unsigned int reference_count;
+
+  /**
+   * Was processing if incoming messages suspended while
+   * we were still processing data already received?
+   * This is a counter saying how often processing was
+   * suspended (once per handler invoked).
+   */
+  unsigned int suspended;
+
+  /**
+   * Are we currently in the "process_client_buffer" function (and
+   * will hence restart the receive job on exit if suspended == 0 once
+   * we are done?).  If this is set, then "receive_done" will
+   * essentially only decrement suspended; if this is not set, then
+   * "receive_done" may need to restart the receive process (either
+   * from the side-buffer or via select/recv).
+   */
+  int in_process_client_buffer;
+
+  /**
+   * We're about to close down this client due to some serious
+   * error.
+   */
+  int shutdown_now;
+
+  /**
+   * Are we currently trying to receive? (YES if we are, NO if we are not,
+   * SYSERR if data is already available in MST).
+   */
+  int receive_pending;
+
+  /**
+   * Finish pending write when disconnecting?
+   */
+  int finish_pending_write;
+
+  /**
+   * Persist the file handle for this client no matter what happens,
+   * force the OS to close once the process actually dies.  Should only
+   * be used in special cases!
+   */
+  int persist;
+
+  /**
+   * Type of last message processed (for warn_no_receive_done).
+   */
+  uint16_t warn_type;
+};
+
+
+/**
+ * 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;
+  struct GNUNET_NETWORK_FDSet *r;
+  unsigned int i;
+
+  server->listen_task = GNUNET_SCHEDULER_NO_TASK;
+  r = GNUNET_NETWORK_fdset_create ();
+  i = 0;
+  while (NULL != server->listen_sockets[i])
+    GNUNET_NETWORK_fdset_set (r, server->listen_sockets[i++]);
+  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_SCHEDULER_NO_TASK,
+                                     GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
+                                     &process_listen_socket, server);
+    GNUNET_NETWORK_fdset_destroy (r);
+    return;
+  }
+  i = 0;
+  while (NULL != server->listen_sockets[i])
+  {
+    if (GNUNET_NETWORK_fdset_isset (tc->read_ready, server->listen_sockets[i]))
+    {
+      sock =
+          GNUNET_CONNECTION_create_from_accept (server->access,
+                                                server->access_cls,
+                                                server->listen_sockets[i]);
+      if (sock != NULL)
+      {
+#if DEBUG_SERVER
+        LOG (GNUNET_ERROR_TYPE_DEBUG, "Server accepted incoming connection.\n");
+#endif
+        client = GNUNET_SERVER_connect_socket (server, sock);
+        GNUNET_CONNECTION_ignore_shutdown (sock,
+                                           server->clients_ignore_shutdown);
+        /* decrement reference count, we don't keep "client" alive */
+        GNUNET_SERVER_client_drop (client);
+      }
+    }
+    i++;
+  }
+  /* listen for more! */
+  server->listen_task =
+      GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
+                                   GNUNET_SCHEDULER_NO_TASK,
+                                   GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
+                                   &process_listen_socket, server);
+  GNUNET_NETWORK_fdset_destroy (r);
+}
+
+
+/**
+ * Create and initialize a listen socket for the server.
+ *
+ * @param serverAddr address to listen on
+ * @param socklen length of address
+ * @return NULL on error, otherwise the listen socket
+ */
+static struct GNUNET_NETWORK_Handle *
+open_listen_socket (const struct sockaddr *serverAddr, socklen_t socklen)
+{
+  const static int on = 1;
+  struct GNUNET_NETWORK_Handle *sock;
+  uint16_t port;
+  int eno;
+
+  switch (serverAddr->sa_family)
+  {
+  case AF_INET:
+    port = ntohs (((const struct sockaddr_in *) serverAddr)->sin_port);
+    break;
+  case AF_INET6:
+    port = ntohs (((const struct sockaddr_in6 *) serverAddr)->sin6_port);
+    break;
+  case AF_UNIX:
+    port = 0;
+    break;
+  default:
+    GNUNET_break (0);
+    port = 0;
+    break;
+  }
+  sock = GNUNET_NETWORK_socket_create (serverAddr->sa_family, SOCK_STREAM, 0);
+  if (NULL == sock)
+  {
+    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "socket");
+    errno = 0;
+    return NULL;
+  }
+  if (port != 0)
+  {
+    if (GNUNET_NETWORK_socket_setsockopt
+        (sock, SOL_SOCKET, SO_REUSEADDR, &on, sizeof (on)) != GNUNET_OK)
+      LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                    "setsockopt");
+#ifdef IPV6_V6ONLY
+    if ((serverAddr->sa_family == AF_INET6) &&
+        (GNUNET_NETWORK_socket_setsockopt
+         (sock, IPPROTO_IPV6, IPV6_V6ONLY, &on, sizeof (on)) != GNUNET_OK))
+      LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR | GNUNET_ERROR_TYPE_BULK,
+                    "setsockopt");
+#endif
+  }
+  /* bind the socket */
+  if (GNUNET_NETWORK_socket_bind (sock, serverAddr, socklen) != GNUNET_OK)
+  {
+    eno = errno;
+    if (errno != EADDRINUSE)
+    {
+      /* we don't log 'EADDRINUSE' here since an IPv4 bind may
+       * fail if we already took the port on IPv6; if both IPv4 and
+       * IPv6 binds fail, then our caller will log using the
+       * errno preserved in 'eno' */
+      LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "bind");
+      if (port != 0)
+        LOG (GNUNET_ERROR_TYPE_ERROR, _("`%s' failed for port %d (%s).\n"),
+             "bind", port,
+             (serverAddr->sa_family == AF_INET) ? "IPv4" : "IPv6");
+      eno = 0;
+    }
+    else
+    {
+      if (port != 0)
+        LOG (GNUNET_ERROR_TYPE_WARNING,
+             _("`%s' failed for port %d (%s): address already in use\n"),
+             "bind", port,
+             (serverAddr->sa_family == AF_INET) ? "IPv4" : "IPv6");
+      else if (serverAddr->sa_family == AF_UNIX)
+        LOG (GNUNET_ERROR_TYPE_WARNING,
+             _("`%s' failed for `%s': address already in use\n"), "bind",
+             ((const struct sockaddr_un *) serverAddr)->sun_path);
+
+    }
+    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
+    errno = eno;
+    return NULL;
+  }
+  if (GNUNET_OK != GNUNET_NETWORK_socket_listen (sock, 5))
+  {
+    LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "listen");
+    GNUNET_break (GNUNET_OK == GNUNET_NETWORK_socket_close (sock));
+    errno = 0;
+    return NULL;
+  }
+#if DEBUG_SERVER
+  if (port != 0)
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Server starts to listen on port %u.\n",
+         port);
+#endif
+  return sock;
+}
+
+
+/**
+ * Create a new server.
+ *
+ * @param access function for access control
+ * @param access_cls closure for access
+ * @param lsocks NULL-terminated array of listen sockets
+ * @param idle_timeout after how long should we timeout idle connections?
+ * @param require_found if YES, connections sending messages of unknown type
+ *        will be closed
+ * @return handle for the new server, NULL on error
+ *         (typically, "port" already in use)
+ */
+struct GNUNET_SERVER_Handle *
+GNUNET_SERVER_create_with_sockets (GNUNET_CONNECTION_AccessCheck access,
+                                   void *access_cls,
+                                   struct GNUNET_NETWORK_Handle **lsocks,
+                                   struct GNUNET_TIME_Relative idle_timeout,
+                                   int require_found)
+{
+  struct GNUNET_SERVER_Handle *ret;
+  struct GNUNET_NETWORK_FDSet *r;
+  int i;
+
+  ret = GNUNET_malloc (sizeof (struct GNUNET_SERVER_Handle));
+  ret->idle_timeout = idle_timeout;
+  ret->listen_sockets = lsocks;
+  ret->access = access;
+  ret->access_cls = access_cls;
+  ret->require_found = require_found;
+  if (lsocks != NULL)
+  {
+    r = GNUNET_NETWORK_fdset_create ();
+    i = 0;
+    while (NULL != ret->listen_sockets[i])
+      GNUNET_NETWORK_fdset_set (r, ret->listen_sockets[i++]);
+    ret->listen_task =
+        GNUNET_SCHEDULER_add_select (GNUNET_SCHEDULER_PRIORITY_HIGH,
+                                     GNUNET_SCHEDULER_NO_TASK,
+                                     GNUNET_TIME_UNIT_FOREVER_REL, r, NULL,
+                                     &process_listen_socket, ret);
+    GNUNET_NETWORK_fdset_destroy (r);
+  }
+  return ret;
+}
+
+
+/**
+ * Create a new server.
+ *
+ * @param access function for access control
+ * @param access_cls closure for access
+ * @param serverAddr address to listen on (including port), NULL terminated array
+ * @param socklen length of serverAddr
+ * @param idle_timeout after how long should we timeout idle connections?
+ * @param require_found if YES, connections sending messages of unknown type
+ *        will be closed
+ * @return handle for the new server, NULL on error
+ *         (typically, "port" already in use)
+ */
+struct GNUNET_SERVER_Handle *
+GNUNET_SERVER_create (GNUNET_CONNECTION_AccessCheck access, void *access_cls,
+                      struct sockaddr *const *serverAddr,
+                      const socklen_t * socklen,
+                      struct GNUNET_TIME_Relative idle_timeout,
+                      int require_found)
+{
+  struct GNUNET_NETWORK_Handle **lsocks;
+  unsigned int i;
+  unsigned int j;
+
+  i = 0;
+  while (serverAddr[i] != NULL)
+    i++;
+  if (i > 0)
+  {
+    lsocks = GNUNET_malloc (sizeof (struct GNUNET_NETWORK_Handle *) * (i + 1));
+    i = 0;
+    j = 0;
+    while (serverAddr[i] != NULL)
+    {
+      lsocks[j] = open_listen_socket (serverAddr[i], socklen[i]);
+      if (lsocks[j] != NULL)
+        j++;
+      i++;
+    }
+    if (j == 0)
+    {
+      if (errno != 0)
+        LOG_STRERROR (GNUNET_ERROR_TYPE_ERROR, "bind");
+      GNUNET_free (lsocks);
+      lsocks = NULL;
+    }
+  }
+  else
+  {
+    lsocks = NULL;
+  }
+  return GNUNET_SERVER_create_with_sockets (access, access_cls, lsocks,
+                                            idle_timeout, require_found);
+}
+
+
+/**
+ * Free resources held by this server.
+ *
+ * @param s server to destroy
+ */
+void
+GNUNET_SERVER_destroy (struct GNUNET_SERVER_Handle *s)
+{
+  struct HandlerList *hpos;
+  struct NotifyList *npos;
+  unsigned int i;
+
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Server shutting down.\n");
+#endif
+  if (GNUNET_SCHEDULER_NO_TASK != s->listen_task)
+  {
+    GNUNET_SCHEDULER_cancel (s->listen_task);
+    s->listen_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (s->listen_sockets != NULL)
+  {
+    i = 0;
+    while (s->listen_sockets[i] != NULL)
+      GNUNET_break (GNUNET_OK ==
+                    GNUNET_NETWORK_socket_close (s->listen_sockets[i++]));
+    GNUNET_free (s->listen_sockets);
+    s->listen_sockets = NULL;
+  }
+  while (s->clients != NULL)
+    GNUNET_SERVER_client_disconnect (s->clients);
+  while (NULL != (hpos = s->handlers))
+  {
+    s->handlers = hpos->next;
+    GNUNET_free (hpos);
+  }
+  while (NULL != (npos = s->disconnect_notify_list))
+  {
+    npos->callback (npos->callback_cls, NULL);
+    s->disconnect_notify_list = npos->next;
+    GNUNET_free (npos);
+  }
+  GNUNET_free (s);
+}
+
+
+/**
+ * Add additional handlers to an existing server.
+ *
+ * @param server the server to add handlers to
+ * @param handlers array of message handlers for
+ *        incoming messages; the last entry must
+ *        have "NULL" for the "callback"; multiple
+ *        entries for the same type are allowed,
+ *        they will be called in order of occurence.
+ *        These handlers can be removed later;
+ *        the handlers array must exist until removed
+ *        (or server is destroyed).
+ */
+void
+GNUNET_SERVER_add_handlers (struct GNUNET_SERVER_Handle *server,
+                            const struct GNUNET_SERVER_MessageHandler *handlers)
+{
+  struct HandlerList *p;
+
+  p = GNUNET_malloc (sizeof (struct HandlerList));
+  p->handlers = handlers;
+  p->next = server->handlers;
+  server->handlers = p;
+}
+
+
+void
+GNUNET_SERVER_set_callbacks (struct GNUNET_SERVER_Handle *server,
+                             GNUNET_SERVER_MstCreateCallback create,
+                             GNUNET_SERVER_MstDestroyCallback destroy,
+                             GNUNET_SERVER_MstReceiveCallback receive,
+                             void *cls)
+{
+  server->mst_create = create;
+  server->mst_destroy = destroy;
+  server->mst_receive = receive;
+  server->mst_cls = cls;
+}
+
+
+/**
+ * Task run to warn about missing calls to 'GNUNET_SERVER_receive_done'.
+ *
+ * @param cls our 'struct GNUNET_SERVER_Client*' to process more requests from
+ * @param tc scheduler context (unused)
+ */
+static void
+warn_no_receive_done (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_SERVER_Client *client = cls;
+
+  client->warn_task =
+      GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
+                                    &warn_no_receive_done, client);
+  if (0 == (GNUNET_SCHEDULER_REASON_SHUTDOWN & tc->reason))
+    LOG (GNUNET_ERROR_TYPE_WARNING,
+         _
+         ("Processing code for message of type %u did not call GNUNET_SERVER_receive_done after %llums\n"),
+         (unsigned int) client->warn_type,
+         (unsigned long long)
+         GNUNET_TIME_absolute_get_duration (client->warn_start).rel_value);
+}
+
+
+/**
+ * Disable the warning the server issues if a message is not acknowledged
+ * in a timely fashion.  Use this call if a client is intentionally delayed
+ * for a while.  Only applies to the current message.
+ *
+ * @param client client for which to disable the warning
+ */
+void
+GNUNET_SERVER_disable_receive_done_warning (struct GNUNET_SERVER_Client *client)
+{
+  if (GNUNET_SCHEDULER_NO_TASK != client->warn_task)
+  {
+    GNUNET_SCHEDULER_cancel (client->warn_task);
+    client->warn_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+}
+
+
+/**
+ * Inject a message into the server, pretend it came
+ * from the specified client.  Delivery of the message
+ * will happen instantly (if a handler is installed;
+ * otherwise the call does nothing).
+ *
+ * @param server the server receiving the message
+ * @param sender the "pretended" sender of the message
+ *        can be NULL!
+ * @param message message to transmit
+ * @return GNUNET_OK if the message was OK and the
+ *                   connection can stay open
+ *         GNUNET_SYSERR if the connection to the
+ *         client should be shut down
+ */
+int
+GNUNET_SERVER_inject (struct GNUNET_SERVER_Handle *server,
+                      struct GNUNET_SERVER_Client *sender,
+                      const struct GNUNET_MessageHeader *message)
+{
+  struct HandlerList *pos;
+  const struct GNUNET_SERVER_MessageHandler *mh;
+  unsigned int i;
+  uint16_t type;
+  uint16_t size;
+  int found;
+
+  type = ntohs (message->type);
+  size = ntohs (message->size);
+#if DEBUG_SERVER
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Server schedules transmission of %u-byte message of type %u to client.\n",
+       size, type);
+#endif
+  pos = server->handlers;
+  found = GNUNET_NO;
+  while (pos != NULL)
+  {
+    i = 0;
+    while (pos->handlers[i].callback != NULL)
+    {
+      mh = &pos->handlers[i];
+      if ((mh->type == type) || (mh->type == GNUNET_MESSAGE_TYPE_ALL))
+      {
+        if ((mh->expected_size != 0) && (mh->expected_size != size))
+        {
+#if GNUNET8_NETWORK_IS_DEAD
+          LOG (GNUNET_ERROR_TYPE_WARNING,
+               "Expected %u bytes for message of type %u, got %u\n",
+               mh->expected_size, mh->type, size);
+          GNUNET_break_op (0);
+#endif
+          return GNUNET_SYSERR;
+        }
+        if (sender != NULL)
+        {
+          if (0 == sender->suspended)
+          {
+            sender->warn_start = GNUNET_TIME_absolute_get ();
+            sender->warn_task =
+                GNUNET_SCHEDULER_add_delayed (GNUNET_TIME_UNIT_MINUTES,
+                                              &warn_no_receive_done, sender);
+            sender->warn_type = type;
+          }
+          sender->suspended++;
+        }
+        mh->callback (mh->callback_cls, sender, message);
+        found = GNUNET_YES;
+      }
+      i++;
+    }
+    pos = pos->next;
+  }
+  if (found == GNUNET_NO)
+  {
+    LOG (GNUNET_ERROR_TYPE_DEBUG | GNUNET_ERROR_TYPE_BULK,
+         "Received message of unknown type %d\n", type);
+    if (server->require_found == GNUNET_YES)
+      return GNUNET_SYSERR;
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * We are receiving an incoming message.  Process it.
+ *
+ * @param cls our closure (handle for the client)
+ * @param buf buffer with data received from network
+ * @param available number of bytes available in buf
+ * @param addr address of the sender
+ * @param addrlen length of addr
+ * @param errCode code indicating errors receiving, 0 for success
+ */
+static void
+process_incoming (void *cls, const void *buf, size_t available,
+                  const struct sockaddr *addr, socklen_t addrlen, int errCode);
+
+
+/**
+ * Process messages from the client's message tokenizer until either
+ * the tokenizer is empty (and then schedule receiving more), or
+ * until some handler is not immediately done (then wait for restart_processing)
+ * or shutdown.
+ *
+ * @param client the client to process, RC must have already been increased
+ *        using GNUNET_SERVER_client_keep and will be decreased by one in this
+ *        function
+ * @param ret GNUNET_NO to start processing from the buffer,
+ *            GNUNET_OK if the mst buffer is drained and we should instantly go back to receiving
+ *            GNUNET_SYSERR if we should instantly abort due to error in a previous step
+ */
+static void
+process_mst (struct GNUNET_SERVER_Client *client, int ret)
+{
+  while ((ret != GNUNET_SYSERR) && (client->server != NULL) &&
+         (GNUNET_YES != client->shutdown_now) && (0 == client->suspended))
+  {
+    if (ret == GNUNET_OK)
+    {
+      client->receive_pending = GNUNET_YES;
+#if DEBUG_SERVER
+      LOG (GNUNET_ERROR_TYPE_DEBUG,
+           "Server re-enters receive loop, timeout: %llu.\n",
+           client->idle_timeout.rel_value);
+#endif
+      GNUNET_CONNECTION_receive (client->connection,
+                                 GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
+                                 client->idle_timeout, &process_incoming,
+                                 client);
+      break;
+    }
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Server processes additional messages instantly.\n");
+#endif
+    if (client->server->mst_receive != NULL)
+      ret =
+          client->server->mst_receive (client->server->mst_cls, client->mst,
+                                       client, NULL, 0, GNUNET_NO, GNUNET_YES);
+    else
+      ret =
+          GNUNET_SERVER_mst_receive (client->mst, client, NULL, 0, GNUNET_NO,
+                                     GNUNET_YES);
+  }
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Server leaves instant processing loop: ret = %d, server = %p, shutdown = %d, suspended = %u\n",
+       ret, client->server, client->shutdown_now, client->suspended);
+#endif
+
+  if (ret == GNUNET_NO)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Server has more data pending but is suspended.\n");
+#endif
+    client->receive_pending = GNUNET_SYSERR;    /* data pending */
+  }
+  if ((ret == GNUNET_SYSERR) || (GNUNET_YES == client->shutdown_now))
+    GNUNET_SERVER_client_disconnect (client);
+  GNUNET_SERVER_client_drop (client);
+}
+
+
+/**
+ * We are receiving an incoming message.  Process it.
+ *
+ * @param cls our closure (handle for the client)
+ * @param buf buffer with data received from network
+ * @param available number of bytes available in buf
+ * @param addr address of the sender
+ * @param addrlen length of addr
+ * @param errCode code indicating errors receiving, 0 for success
+ */
+static void
+process_incoming (void *cls, const void *buf, size_t available,
+                  const struct sockaddr *addr, socklen_t addrlen, int errCode)
+{
+  struct GNUNET_SERVER_Client *client = cls;
+  struct GNUNET_SERVER_Handle *server = client->server;
+  struct GNUNET_TIME_Absolute end;
+  struct GNUNET_TIME_Absolute now;
+  int ret;
+
+  GNUNET_assert (client->receive_pending == GNUNET_YES);
+  client->receive_pending = GNUNET_NO;
+  now = GNUNET_TIME_absolute_get ();
+  end = GNUNET_TIME_absolute_add (client->last_activity, client->idle_timeout);
+
+  if ((buf == NULL) && (available == 0) && (addr == NULL) && (errCode == 0) &&
+      (client->shutdown_now != GNUNET_YES) && (server != NULL) &&
+      (GNUNET_YES == GNUNET_CONNECTION_check (client->connection)) &&
+      (end.abs_value > now.abs_value))
+  {
+    /* wait longer, timeout changed (i.e. due to us sending) */
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Receive time out, but no disconnect due to sending (%p)\n",
+         GNUNET_a2s (addr, addrlen));
+#endif
+    client->receive_pending = GNUNET_YES;
+    GNUNET_CONNECTION_receive (client->connection,
+                               GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
+                               GNUNET_TIME_absolute_get_remaining (end),
+                               &process_incoming, client);
+    return;
+  }
+  if ((buf == NULL) || (available == 0) || (errCode != 0) || (server == NULL) ||
+      (client->shutdown_now == GNUNET_YES) ||
+      (GNUNET_YES != GNUNET_CONNECTION_check (client->connection)))
+  {
+    /* other side closed connection, error connecting, etc. */
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG, "Server receives %u bytes from `%s'.\n",
+       (unsigned int) available, GNUNET_a2s (addr, addrlen));
+#endif
+  GNUNET_SERVER_client_keep (client);
+  client->last_activity = now;
+
+  if (server->mst_receive != NULL)
+    ret =
+        client->server->mst_receive (client->server->mst_cls, client->mst,
+                                     client, buf, available, GNUNET_NO, GNUNET_YES);
+  else
+    ret =
+        GNUNET_SERVER_mst_receive (client->mst, client, buf, available, GNUNET_NO,
+                                   GNUNET_YES);
+
+  process_mst (client, ret);
+}
+
+
+/**
+ * Task run to start again receiving from the network
+ * and process requests.
+ *
+ * @param cls our 'struct GNUNET_SERVER_Client*' to process more requests from
+ * @param tc scheduler context (unused)
+ */
+static void
+restart_processing (void *cls, const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_SERVER_Client *client = cls;
+  struct GNUNET_SERVER_Handle *server = client->server;
+
+  client->restart_task = GNUNET_SCHEDULER_NO_TASK;
+  if ((0 != (tc->reason & GNUNET_SCHEDULER_REASON_SHUTDOWN)) &&
+      (GNUNET_NO == server->clients_ignore_shutdown))
+  {
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+  if (client->receive_pending == GNUNET_NO)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG, "Server begins to read again from client.\n");
+#endif
+    client->receive_pending = GNUNET_YES;
+    GNUNET_CONNECTION_receive (client->connection,
+                               GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
+                               client->idle_timeout, &process_incoming, client);
+    return;
+  }
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Server continues processing messages still in the buffer.\n");
+#endif
+  GNUNET_SERVER_client_keep (client);
+  client->receive_pending = GNUNET_NO;
+  process_mst (client, GNUNET_NO);
+}
+
+
+/**
+ * This function is called whenever our inbound message tokenizer has
+ * received a complete message.
+ *
+ * @param cls closure (struct GNUNET_SERVER_Handle)
+ * @param client identification of the client (struct GNUNET_SERVER_Client*)
+ * @param message the actual message
+ */
+static void
+client_message_tokenizer_callback (void *cls, void *client,
+                                   const struct GNUNET_MessageHeader *message)
+{
+  struct GNUNET_SERVER_Handle *server = cls;
+  struct GNUNET_SERVER_Client *sender = client;
+  int ret;
+
+#if DEBUG_SERVER
+
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Tokenizer gives server message of type %u from client\n",
+       ntohs (message->type));
+#endif
+  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)
+    GNUNET_SERVER_client_disconnect (sender);
+}
+
+
+/**
+ * Add a TCP socket-based connection to the set of handles managed by
+ * this server.  Use this function for outgoing (P2P) connections that
+ * we initiated (and where this server should process incoming
+ * messages).
+ *
+ * @param server the server to use
+ * @param connection the connection to manage (client must
+ *        stop using this connection from now on)
+ * @return the client handle (client should call
+ *         "client_drop" on the return value eventually)
+ */
+struct GNUNET_SERVER_Client *
+GNUNET_SERVER_connect_socket (struct GNUNET_SERVER_Handle *server,
+                              struct GNUNET_CONNECTION_Handle *connection)
+{
+  struct GNUNET_SERVER_Client *client;
+
+  client = GNUNET_malloc (sizeof (struct GNUNET_SERVER_Client));
+  client->connection = connection;
+  client->mst =
+      GNUNET_SERVER_mst_create (&client_message_tokenizer_callback, 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;
+  client->receive_pending = GNUNET_YES;
+  client->callback = NULL;
+  client->callback_cls = NULL;
+
+  if (server->mst_create != NULL)
+    client->mst =
+        server->mst_create (server->mst_cls, client);
+  else
+    client->mst =
+        GNUNET_SERVER_mst_create (&client_message_tokenizer_callback, server);
+
+  GNUNET_CONNECTION_receive (client->connection,
+                             GNUNET_SERVER_MAX_MESSAGE_SIZE - 1,
+                             client->idle_timeout, &process_incoming, client);
+  return client;
+}
+
+
+/**
+ * Change the timeout for a particular client.  Decreasing the timeout
+ * may not go into effect immediately (only after the previous timeout
+ * times out or activity happens on the socket).
+ *
+ * @param client the client to update
+ * @param timeout new timeout for activities on the socket
+ */
+void
+GNUNET_SERVER_client_set_timeout (struct GNUNET_SERVER_Client *client,
+                                  struct GNUNET_TIME_Relative timeout)
+{
+  client->idle_timeout = timeout;
+}
+
+
+void
+GNUNET_SERVER_client_set_finish_pending_write (struct GNUNET_SERVER_Client *client,
+                                               int finish)
+{
+  client->finish_pending_write = finish;
+}
+
+
+/**
+ * Notify the server that the given client handle should
+ * be kept (keeps the connection up if possible, increments
+ * the internal reference counter).
+ *
+ * @param client the client to keep
+ */
+void
+GNUNET_SERVER_client_keep (struct GNUNET_SERVER_Client *client)
+{
+  client->reference_count++;
+}
+
+
+/**
+ * Notify the server that the given client handle is no
+ * longer required.  Decrements the reference counter.  If
+ * that counter reaches zero an inactive connection maybe
+ * closed.
+ *
+ * @param client the client to drop
+ */
+void
+GNUNET_SERVER_client_drop (struct GNUNET_SERVER_Client *client)
+{
+  GNUNET_assert (client->reference_count > 0);
+  client->reference_count--;
+  if ((client->shutdown_now == GNUNET_YES) && (client->reference_count == 0))
+    GNUNET_SERVER_client_disconnect (client);
+}
+
+
+/**
+ * Obtain the network address of the other party.
+ *
+ * @param client the client to get the address for
+ * @param addr where to store the address
+ * @param addrlen where to store the length of the address
+ * @return GNUNET_OK on success
+ */
+int
+GNUNET_SERVER_client_get_address (struct GNUNET_SERVER_Client *client,
+                                  void **addr, size_t * addrlen)
+{
+  return GNUNET_CONNECTION_get_address (client->connection, addr, addrlen);
+}
+
+
+/**
+ * Ask the server to notify us whenever a client disconnects.
+ * This function is called whenever the actual network connection
+ * is closed; the reference count may be zero or larger than zero
+ * at this point.
+ *
+ * @param server the server manageing the clients
+ * @param callback function to call on disconnect
+ * @param callback_cls closure for callback
+ */
+void
+GNUNET_SERVER_disconnect_notify (struct GNUNET_SERVER_Handle *server,
+                                 GNUNET_SERVER_DisconnectCallback callback,
+                                 void *callback_cls)
+{
+  struct NotifyList *n;
+
+  n = GNUNET_malloc (sizeof (struct NotifyList));
+  n->callback = callback;
+  n->callback_cls = callback_cls;
+  n->next = server->disconnect_notify_list;
+  server->disconnect_notify_list = n;
+}
+
+
+/**
+ * Ask the server to stop notifying us whenever a client disconnects.
+ *
+ * @param server the server manageing the clients
+ * @param callback function to call on disconnect
+ * @param callback_cls closure for callback
+ */
+void
+GNUNET_SERVER_disconnect_notify_cancel (struct GNUNET_SERVER_Handle *server,
+                                        GNUNET_SERVER_DisconnectCallback
+                                        callback, void *callback_cls)
+{
+  struct NotifyList *pos;
+  struct NotifyList *prev;
+
+  prev = NULL;
+  pos = server->disconnect_notify_list;
+  while (pos != NULL)
+  {
+    if ((pos->callback == callback) && (pos->callback_cls == callback_cls))
+      break;
+    prev = pos;
+    pos = pos->next;
+  }
+  if (pos == NULL)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  if (prev == NULL)
+    server->disconnect_notify_list = pos->next;
+  else
+    prev->next = pos->next;
+  GNUNET_free (pos);
+}
+
+
+/**
+ * Ask the server to disconnect from the given client.
+ * This is the same as returning GNUNET_SYSERR from a message
+ * handler, except that it allows dropping of a client even
+ * when not handling a message from that client.
+ *
+ * @param client the client to disconnect from
+ */
+void
+GNUNET_SERVER_client_disconnect (struct GNUNET_SERVER_Client *client)
+{
+  struct GNUNET_SERVER_Client *prev;
+  struct GNUNET_SERVER_Client *pos;
+  struct GNUNET_SERVER_Handle *server;
+  struct NotifyList *n;
+  unsigned int rc;
+
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "Client is being disconnected from the server.\n");
+#endif
+  if (client->restart_task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (client->restart_task);
+    client->restart_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (client->warn_task != GNUNET_SCHEDULER_NO_TASK)
+  {
+    GNUNET_SCHEDULER_cancel (client->warn_task);
+    client->warn_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (GNUNET_YES == client->receive_pending)
+  {
+    GNUNET_CONNECTION_receive_cancel (client->connection);
+    client->receive_pending = GNUNET_NO;
+  }
+
+  rc = client->reference_count;
+  if (client->shutdown_now != GNUNET_YES)
+  {
+    server = client->server;
+    client->shutdown_now = GNUNET_YES;
+    prev = NULL;
+    pos = server->clients;
+    while ((pos != NULL) && (pos != client))
+    {
+      prev = pos;
+      pos = pos->next;
+    }
+    GNUNET_assert (pos != NULL);
+    if (prev == NULL)
+      server->clients = pos->next;
+    else
+      prev->next = pos->next;
+    if (client->restart_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (client->restart_task);
+      client->restart_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+    if (client->warn_task != GNUNET_SCHEDULER_NO_TASK)
+    {
+      GNUNET_SCHEDULER_cancel (client->warn_task);
+      client->warn_task = GNUNET_SCHEDULER_NO_TASK;
+    }
+    n = server->disconnect_notify_list;
+    while (n != NULL)
+    {
+      n->callback (n->callback_cls, client);
+      n = n->next;
+    }
+  }
+  if (rc > 0)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "RC still positive, not destroying everything.\n");
+#endif
+    return;
+  }
+  if (client->in_process_client_buffer == GNUNET_YES)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "Still processing inputs, not destroying everything.\n");
+#endif
+    return;
+  }
+
+  if (client->persist == GNUNET_YES)
+    GNUNET_CONNECTION_persist_ (client->connection);
+  GNUNET_CONNECTION_destroy (client->connection, client->finish_pending_write);
+
+  if (client->server->mst_destroy != NULL)
+    client->server->mst_destroy (client->server->mst_cls, client->mst);
+  else
+    GNUNET_SERVER_mst_destroy (client->mst);
+
+  GNUNET_free (client);
+}
+
+
+/**
+ * Disable the "CORK" feature for communication with the given client,
+ * forcing the OS to immediately flush the buffer on transmission
+ * instead of potentially buffering multiple messages.
+ *
+ * @param client handle to the client
+ * @return GNUNET_OK on success
+ */
+int
+GNUNET_SERVER_client_disable_corking (struct GNUNET_SERVER_Client *client)
+{
+  return GNUNET_CONNECTION_disable_corking (client->connection);
+}
+
+
+/**
+ * Wrapper for transmission notification that calls the original
+ * callback and update the last activity time for our connection.
+ *
+ * @param cls the 'struct GNUNET_SERVER_Client'
+ * @param size number of bytes we can transmit
+ * @param buf where to copy the message
+ * @return number of bytes actually transmitted
+ */
+static size_t
+transmit_ready_callback_wrapper (void *cls, size_t size, void *buf)
+{
+  struct GNUNET_SERVER_Client *client = cls;
+  size_t ret;
+
+  ret = client->callback (client->callback_cls, size, buf);
+  if (ret > 0)
+    client->last_activity = GNUNET_TIME_absolute_get ();
+  return ret;
+}
+
+
+/**
+ * Notify us when the server has enough space to transmit
+ * a message of the given size to the given client.
+ *
+ * @param client client to transmit message to
+ * @param size requested amount of buffer space
+ * @param timeout after how long should we give up (and call
+ *        notify with buf NULL and size 0)?
+ * @param callback function to call when space is available
+ * @param callback_cls closure for callback
+ * @return non-NULL if the notify callback was queued; can be used
+ *           to cancel the request using
+ *           GNUNET_CONNECTION_notify_transmit_ready_cancel.
+ *         NULL if we are already going to notify someone else (busy)
+ */
+struct GNUNET_CONNECTION_TransmitHandle *
+GNUNET_SERVER_notify_transmit_ready (struct GNUNET_SERVER_Client *client,
+                                     size_t size,
+                                     struct GNUNET_TIME_Relative timeout,
+                                     GNUNET_CONNECTION_TransmitReadyNotify
+                                     callback, void *callback_cls)
+{
+  client->callback_cls = callback_cls;
+  client->callback = callback;
+  return GNUNET_CONNECTION_notify_transmit_ready (client->connection, size,
+                                                  timeout,
+                                                  &transmit_ready_callback_wrapper,
+                                                  client);
+}
+
+
+/**
+ * Set the persistent flag on this client, used to setup client connection
+ * to only be killed when the service it's connected to is actually dead.
+ *
+ * @param client the client to set the persistent flag on
+ */
+void
+GNUNET_SERVER_client_persist_ (struct GNUNET_SERVER_Client *client)
+{
+  client->persist = GNUNET_YES;
+}
+
+
+/**
+ * Resume receiving from this client, we are done processing the
+ * current request.  This function must be called from within each
+ * GNUNET_SERVER_MessageCallback (or its respective continuations).
+ *
+ * @param client client we were processing a message of
+ * @param success GNUNET_OK to keep the connection open and
+ *                          continue to receive
+ *                GNUNET_NO to close the connection (normal behavior)
+ *                GNUNET_SYSERR to close the connection (signal
+ *                          serious error)
+ */
+void
+GNUNET_SERVER_receive_done (struct GNUNET_SERVER_Client *client, int success)
+{
+  if (client == NULL)
+    return;
+  GNUNET_assert (client->suspended > 0);
+  client->suspended--;
+  if (success != GNUNET_OK)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "GNUNET_SERVER_receive_done called with failure indication\n");
+#endif
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+  if (client->suspended > 0)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "GNUNET_SERVER_receive_done called, but more clients pending\n");
+#endif
+    return;
+  }
+  if (GNUNET_SCHEDULER_NO_TASK != client->warn_task)
+  {
+    GNUNET_SCHEDULER_cancel (client->warn_task);
+    client->warn_task = GNUNET_SCHEDULER_NO_TASK;
+  }
+  if (client->in_process_client_buffer == GNUNET_YES)
+  {
+#if DEBUG_SERVER
+    LOG (GNUNET_ERROR_TYPE_DEBUG,
+         "GNUNET_SERVER_receive_done called while still in processing loop\n");
+#endif
+    return;
+  }
+  if ((client->server == NULL) || (GNUNET_YES == client->shutdown_now))
+  {
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+#if DEBUG_SERVER
+  LOG (GNUNET_ERROR_TYPE_DEBUG,
+       "GNUNET_SERVER_receive_done causes restart in reading from the socket\n");
+#endif
+  GNUNET_assert (GNUNET_SCHEDULER_NO_TASK == client->restart_task);
+  client->restart_task = GNUNET_SCHEDULER_add_now (&restart_processing, client);
+}
+
+
+/**
+ * Configure this server's connections to continue handling client
+ * requests as usual even after we get a shutdown signal.  The change
+ * only applies to clients that connect to the server from the outside
+ * using TCP after this call.  Clients managed previously or those
+ * added using GNUNET_SERVER_connect_socket and
+ * GNUNET_SERVER_connect_callback are not affected by this option.
+ *
+ * @param h server handle
+ * @param do_ignore GNUNET_YES to ignore, GNUNET_NO to restore default
+ */
+void
+GNUNET_SERVER_ignore_shutdown (struct GNUNET_SERVER_Handle *h, int do_ignore)
+{
+  h->clients_ignore_shutdown = do_ignore;
+}
+
+/* end of server.c */