1 files changed, 608 insertions, 0 deletions

diff --git a/src/consensus/gnunet-service-consensus.c b/src/consensus/gnunet-service-consensus.c
new file mode 100644
index 000000000..6cf3c0653
--- /dev/null
+++ b/src/consensus/gnunet-service-consensus.c
@@ -0,0 +1,608 @@
+/*
+      This file is part of GNUnet
+      (C) 2012 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.
+ */
+
+
+#include "platform.h"
+#include "gnunet_protocols.h"
+#include "gnunet_common.h"
+#include "gnunet_service_lib.h"
+#include "gnunet_consensus_service.h"
+#include "gnunet_core_service.h"
+#include "gnunet_container_lib.h"
+#include "consensus.h"
+
+
+struct ConsensusClient;
+
+static void
+send_next (struct ConsensusClient *cli);
+
+
+/**
+ * An element that is waiting to be transmitted to a client.
+ */
+struct PendingElement
+{
+  /**
+   * Pending elements are kept in a DLL.
+   */
+  struct PendingElement *next;
+
+  /**
+   * Pending elements are kept in a DLL.
+   */
+  struct PendingElement *prev;
+
+  /**
+   * The actual element
+   */
+  struct GNUNET_CONSENSUS_Element *element;
+};
+
+
+/**
+ * A consensus session consists of one or more local clients,
+ * as well as zero or more remote authorities.
+ */
+struct ConsensusSession
+{
+  /**
+   * Consensus sessions are kept in a DLL.
+   */
+  struct ConsensusSession *next;
+
+  /**
+   * Consensus sessions are kept in a DLL.
+   */
+  struct ConsensusSession *prev;
+
+  /**
+   * Consensus clients are kept in a DLL.
+   */
+  struct ConsensusClient *clients_head;
+
+  /**
+   * Consensus clients are kept in a DLL.
+   */
+  struct ConsensusClient *clients_tail;
+
+  /**
+  * Local consensus identification, chosen by clients.
+  */
+  struct GNUNET_HashCode *local_id;
+ 
+  /**
+  * Global consensus identification, computed
+  * from the local id and participating authorities.
+  */
+  struct GNUNET_HashCode *global_id;
+
+  /**
+   * Values in the consensus set of this session.
+   */
+  struct GNUNET_CONTAINER_MultiHashMap *values;
+};
+
+
+struct ConsensusClient
+{
+  /**
+   * Consensus clients are kept in a DLL.
+   */
+  struct ConsensusClient *next;
+  /**
+   * Consensus clients are kept in a DLL.
+   */
+  struct ConsensusClient *prev;
+
+  /**
+   * Corresponding server handle.
+   */
+  struct GNUNET_SERVER_Client *client;
+
+  /**
+   * Client wants to receive and send updates.
+   */
+  int begin;
+
+  /**
+   * Session this client belongs to
+   */
+  struct ConsensusSession *session;
+
+  /**
+   * Values in the consensus set of this client.
+   * Includes pending elements.
+   */
+  struct GNUNET_CONTAINER_MultiHashMap *values;
+
+  /**
+   * Elements that have not been set to the client yet.
+   */
+  struct PendingElement *pending_head;
+  /**
+   * Elements that have not been set to the client yet.
+   */
+  struct PendingElement *pending_tail;
+
+  /**
+   * Currently active transmit handle for sending to the client
+   */
+  struct GNUNET_SERVER_TransmitHandle *th;
+
+  /**
+   * Once conclude_requested is GNUNET_YES, the client may not
+   * insert any more values.
+   */
+  int conclude_requested;
+
+  /**
+   * Client has been informed about the conclusion.
+   */
+  int conclude_sent;
+};
+
+
+/**
+ * Linked list of sesstions this peer participates in.
+ */
+static struct ConsensusSession *sessions_head;
+
+/**
+ * Linked list of sesstions this peer participates in.
+ */
+static struct ConsensusSession *sessions_tail;
+
+/**
+ * Configuration of the consensus service.
+ */
+static const struct GNUNET_CONFIGURATION_Handle *cfg;
+
+/**
+ * Handle to the server for this service.
+ */
+static struct GNUNET_SERVER_Handle *srv;
+
+/**
+ * Peer that runs this service
+ */
+static struct GNUNET_PeerIdentity *my_peer;
+
+
+struct ConsensusClient *
+find_client (const struct GNUNET_SERVER_Client *srv_client)
+{
+  struct ConsensusSession *session;
+  struct ConsensusClient *client;
+
+  session = sessions_head;
+  while (NULL != session)
+  {
+    client = session->clients_head;
+    while (NULL != client)
+    {
+      if (client->client == srv_client)
+      {
+        return client;
+      }
+      client = client->next;
+    }
+    session = session->next;
+  }
+  return NULL;
+}
+
+static void
+disconnect_client (struct GNUNET_SERVER_Client *client)
+{
+  /* FIXME */
+}
+
+static void
+compute_global_id (struct GNUNET_HashCode *dst,
+                   const struct GNUNET_HashCode *local_id,
+                   const struct GNUNET_PeerIdentity *peers,
+                   int num_peers)
+{
+  *dst = *local_id;
+
+  /* FIXME: hash other peers into global id */
+}
+
+
+
+/**
+ * Iterator over hash map entries.
+ *
+ * @param cls closure, the client
+ * @param key current key code
+ * @param value value in the hash map
+ * @return GNUNET_YES if we should continue to
+ *         iterate,
+ *         GNUNET_NO if not.
+ */
+int
+update_pending (void *cls,
+                 const struct GNUNET_HashCode *key,
+                 void *value)
+{
+  struct ConsensusClient *cli;
+  struct GNUNET_CONSENSUS_Element *element;
+  struct PendingElement *pending_element;
+
+  cli = (struct ConsensusClient *) cls;
+  element = (struct GNUNET_CONSENSUS_Element *) value;
+  pending_element = GNUNET_malloc (sizeof (struct PendingElement));
+  pending_element->element = element;
+
+  if (GNUNET_NO == GNUNET_CONTAINER_multihashmap_contains (cli->values, key))
+  {
+    GNUNET_CONTAINER_DLL_insert_tail (cli->pending_head, cli->pending_tail, pending_element);
+    GNUNET_CONTAINER_multihashmap_put (cli->values, key, element, GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+  }
+  
+  return GNUNET_YES;
+}
+
+
+
+
+static size_t
+transmit_pending (void *cls, size_t size, void *buf)
+{
+  struct GNUNET_CONSENSUS_Element *element;
+  struct GNUNET_CONSENSUS_ElementMessage *msg;
+  struct ConsensusClient *cli;
+
+  cli = (struct ConsensusClient *) cls;
+  msg = (struct GNUNET_CONSENSUS_ElementMessage *) buf;
+  element = cli->pending_head->element;
+
+  GNUNET_assert (NULL != element);
+
+  cli->th = NULL;
+
+  msg->element_type = element->type;
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_RECEIVED_ELEMENT);
+  msg->header.size = htons (sizeof (struct GNUNET_CONSENSUS_ElementMessage) + element->size);
+  memcpy (&msg[1], &element[1], element->size);
+
+
+  cli->pending_head = cli->pending_head->next;
+
+  send_next (cli);
+
+  return sizeof (struct GNUNET_CONSENSUS_ElementMessage) + element->size;
+}
+
+
+static size_t
+transmit_conclude_done (void *cls, size_t size, void *buf)
+{
+  struct GNUNET_CONSENSUS_ConcludeDoneMessage *msg;
+
+  msg = (struct GNUNET_CONSENSUS_ConcludeDoneMessage *) buf;
+  msg->header.type = htons (GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE);
+  msg->header.size = htons (sizeof (struct GNUNET_CONSENSUS_ConcludeDoneMessage));
+  msg->num_peers = htons (0);
+
+  return sizeof (struct GNUNET_CONSENSUS_ConcludeDoneMessage);
+}
+
+
+/**
+ * Schedule sending the next message (if there is any) to a client.
+ *
+ * @param cli the client to send the next message to
+ */
+static void
+send_next (struct ConsensusClient *cli)
+{
+  int msize;
+
+  GNUNET_assert (NULL != cli);
+
+  if (NULL != cli->th)
+  {
+    return;
+  }
+
+  if ((cli->conclude_requested == GNUNET_YES) && (cli->conclude_sent == GNUNET_NO))
+  {
+    /* just the conclude message with no other authorities in the dummy */
+    msize = sizeof (struct GNUNET_CONSENSUS_ConcludeMessage);
+    cli->th =
+        GNUNET_SERVER_notify_transmit_ready (cli->client, msize,
+                                             GNUNET_TIME_UNIT_FOREVER_REL, &transmit_conclude_done, cli);
+    cli->conclude_sent = GNUNET_YES;
+  }
+  else if (NULL != cli->pending_head)
+  {
+    msize = cli->pending_head->element->size + sizeof (struct GNUNET_CONSENSUS_ElementMessage);
+    cli->th =
+        GNUNET_SERVER_notify_transmit_ready (cli->client, msize,
+                                             GNUNET_TIME_UNIT_FOREVER_REL, &transmit_pending, cli);
+  }
+}
+
+
+/**
+ * Called when a client wants to join a consensus session.
+ */
+static void
+client_join (void *cls,
+             struct GNUNET_SERVER_Client *client,
+             const struct GNUNET_MessageHeader *m)
+{
+  struct GNUNET_HashCode global_id;
+  const struct GNUNET_CONSENSUS_JoinMessage *msg;
+  struct ConsensusSession *session;
+  struct ConsensusClient *consensus_client;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "join\n");
+
+  fprintf(stderr, "foobar\n");
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "client joined\n");
+
+  msg = (struct GNUNET_CONSENSUS_JoinMessage *) m;
+  
+  /* kill the client if it already is in a session */
+  if (NULL != find_client (client))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "client tried to join twice\n");
+    disconnect_client (client);
+    return;
+  }
+
+  consensus_client = GNUNET_malloc (sizeof (struct ConsensusClient));
+  consensus_client->client = client;
+  consensus_client->begin = GNUNET_NO;
+  consensus_client->values = GNUNET_CONTAINER_multihashmap_create (4, GNUNET_NO);
+
+  GNUNET_SERVER_client_keep (client);
+
+  GNUNET_assert (NULL != consensus_client->values);
+
+  compute_global_id (&global_id, &msg->session_id, (struct GNUNET_PeerIdentity *) &m[1], msg->num_peers);
+
+  /* look if we already have a session for this local id */
+  session = sessions_head;
+  while (NULL != session)
+  {
+    if (0 == memcmp(&global_id, session->global_id, sizeof (struct GNUNET_HashCode)))
+    {
+      GNUNET_CONTAINER_DLL_insert (session->clients_head, session->clients_tail, consensus_client);
+      GNUNET_SERVER_receive_done (client, GNUNET_OK);
+      return;
+    }
+    session = session->next;
+  }
+
+  /* session does not exist yet, create it */
+  session = GNUNET_malloc (sizeof (struct ConsensusSession));
+  session->local_id = GNUNET_memdup (&msg->session_id, sizeof (struct GNUNET_HashCode));
+  session->global_id = GNUNET_memdup (&global_id, sizeof (struct GNUNET_HashCode));
+  session->values = GNUNET_CONTAINER_multihashmap_create (4, GNUNET_NO);
+
+  GNUNET_CONTAINER_DLL_insert (sessions_head, sessions_tail, session);
+  GNUNET_CONTAINER_DLL_insert (session->clients_head, session->clients_tail, consensus_client);
+
+  GNUNET_log (GNUNET_ERROR_TYPE_INFO, "created new session");
+
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * Called when a client performs an insert operation.
+ */
+void
+client_insert (void *cls,
+             struct GNUNET_SERVER_Client *client,
+             const struct GNUNET_MessageHeader *m)
+{
+  struct ConsensusClient *consensus_client;
+  struct GNUNET_CONSENSUS_ElementMessage *msg;
+  struct GNUNET_CONSENSUS_Element *element;
+  struct PendingElement *pending_element;
+  struct GNUNET_HashCode key;
+  int element_size;
+
+  GNUNET_log(GNUNET_ERROR_TYPE_INFO, "insert\n");
+
+  consensus_client = find_client (client);
+
+  if (NULL == consensus_client)
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING, "client tried to insert, but client is not in any session\n");
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+
+  msg = (struct GNUNET_CONSENSUS_ElementMessage *) m;
+  element_size = msg->header.size - sizeof (struct GNUNET_CONSENSUS_ElementMessage);
+
+  element = GNUNET_malloc (sizeof (struct GNUNET_CONSENSUS_Element) + element_size);
+
+  element->type = msg->element_type;
+  element->size = element_size;
+  memcpy (&element[1], &msg[1], element_size);
+  element->data = &element[1];
+
+  GNUNET_CRYPTO_hash (element, element_size, &key);
+
+  GNUNET_CONTAINER_multihashmap_put (consensus_client->session->values, &key, element,
+                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_REPLACE);
+  GNUNET_CONTAINER_multihashmap_put (consensus_client->values, &key, element,
+                                     GNUNET_CONTAINER_MULTIHASHMAPOPTION_REPLACE);
+
+  /* send the new value to all clients that don't have it */
+
+  consensus_client = consensus_client->session->clients_head;
+  while (NULL != consensus_client)
+  {
+    if (GNUNET_NO == GNUNET_CONTAINER_multihashmap_contains (consensus_client->values, &key))
+    {
+      pending_element = GNUNET_malloc (sizeof (struct PendingElement));
+      pending_element->element = element;
+      GNUNET_CONTAINER_DLL_insert_tail (consensus_client->pending_head, consensus_client->pending_tail, pending_element);
+      GNUNET_CONTAINER_multihashmap_put (consensus_client->values, &key, element,
+                                         GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY);
+      send_next (consensus_client);
+    }
+  }
+
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+/**
+ * Called when a client wants to begin
+ */
+void
+client_begin (void *cls,
+             struct GNUNET_SERVER_Client *client,
+             const struct GNUNET_MessageHeader *message)
+{
+  struct ConsensusClient *consensus_client;
+
+  consensus_client = find_client (client);
+
+  if (NULL == consensus_client)
+  {
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+
+  consensus_client->begin = GNUNET_YES;
+
+  GNUNET_CONTAINER_multihashmap_iterate (consensus_client->session->values, &update_pending, NULL);
+  send_next (consensus_client);
+
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+
+
+/**
+ * Called when a client performs the conclude operation.
+ */
+void
+client_conclude (void *cls,
+             struct GNUNET_SERVER_Client *client,
+             const struct GNUNET_MessageHeader *message)
+{
+  struct ConsensusClient *consensus_client;
+
+  consensus_client = find_client (client);
+  if (NULL == consensus_client)
+  {
+    GNUNET_SERVER_client_disconnect (client);
+    return;
+  }
+  consensus_client->conclude_requested = GNUNET_YES;
+  send_next (consensus_client);
+
+  GNUNET_SERVER_receive_done (client, GNUNET_OK);
+}
+
+/**
+ * Task that disconnects from core.
+ *
+ * @param cls core handle
+ * @param tc context information (why was this task triggered now)
+ */
+static void
+disconnect_core (void *cls,
+                 const struct GNUNET_SCHEDULER_TaskContext *tc)
+{
+  struct GNUNET_CORE_Handle *core;
+  core = (struct GNUNET_CORE_Handle *) cls;
+  GNUNET_CORE_disconnect (core);
+
+  GNUNET_log(GNUNET_ERROR_TYPE_INFO, "disconnected from core\n");
+}
+
+
+static void
+core_startup (void *cls,
+              struct GNUNET_CORE_Handle *core,
+              const struct GNUNET_PeerIdentity *peer)
+{
+  static const struct GNUNET_SERVER_MessageHandler handlers[] = {
+    {&client_join, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_JOIN, 0},
+    {&client_insert, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_INSERT, 0},
+    {&client_begin, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_BEGIN,
+        sizeof (struct GNUNET_MessageHeader)},
+    {&client_conclude, NULL, GNUNET_MESSAGE_TYPE_CONSENSUS_CLIENT_CONCLUDE,
+        sizeof (struct GNUNET_CONSENSUS_ConcludeMessage)},
+    {NULL, NULL, 0, 0}
+  };
+
+
+  GNUNET_SERVER_add_handlers (srv, handlers);
+
+  my_peer = GNUNET_memdup(peer, sizeof (struct GNUNET_PeerIdentity));
+
+  GNUNET_SCHEDULER_add_now (&disconnect_core, core);
+
+  GNUNET_log(GNUNET_ERROR_TYPE_INFO, "connected to core\n");
+}
+
+
+/**
+ * Process consensus requests.
+ *
+ * @param cls closure
+ * @param server the initialized server
+ * @param c configuration to use
+ */
+static void
+run (void *cls, struct GNUNET_SERVER_Handle *server, const struct GNUNET_CONFIGURATION_Handle *c)
+{
+  struct GNUNET_CORE_Handle *my_core;
+  static const struct GNUNET_CORE_MessageHandler handlers[] = {
+    {NULL, 0, 0}
+  };
+
+  GNUNET_log(GNUNET_ERROR_TYPE_INFO, "run\n");
+
+  cfg = c;
+  srv = server;
+  my_core = GNUNET_CORE_connect (c, NULL, &core_startup, NULL, NULL, NULL, GNUNET_NO, NULL, GNUNET_NO, handlers);
+  GNUNET_assert (NULL != my_core);
+}
+
+
+/**
+ * The main function for the statistics service.
+ *
+ * @param argc number of arguments from the command line
+ * @param argv command line arguments
+ * @return 0 ok, 1 on error
+ */
+int
+main (int argc, char *const *argv)
+{
+  return (GNUNET_OK ==
+          GNUNET_SERVICE_run (argc, argv, "consensus", GNUNET_SERVICE_OPTION_NONE, &run, NULL)) ? 0 : 1;
+}
+