converting core service to new service API

1 files changed, 854 insertions, 27 deletions

diff --git a/src/core/gnunet-service-core.c b/src/core/gnunet-service-core.c
index f9391e616..acaa10092 100644
--- a/src/core/gnunet-service-core.c
+++ b/src/core/gnunet-service-core.c
@@ -1,6 +1,6 @@
 /*
      This file is part of GNUnet.
-     Copyright (C) 2009, 2010, 2011 GNUnet e.V.
+     Copyright (C) 2009, 2010, 2011, 2016 GNUnet e.V.
 
      GNUnet is free software; you can redistribute it and/or modify
      it under the terms of the GNU General Public License as published
@@ -27,11 +27,75 @@
 #include <gcrypt.h>
 #include "gnunet_util_lib.h"
 #include "gnunet-service-core.h"
-#include "gnunet-service-core_clients.h"
 #include "gnunet-service-core_kx.h"
 #include "gnunet-service-core_sessions.h"
 #include "gnunet-service-core_typemap.h"
 
+/**
+ * How many messages do we queue up at most for optional
+ * notifications to a client?  (this can cause notifications
+ * about outgoing messages to be dropped).
+ */
+#define MAX_NOTIFY_QUEUE 1024
+
+
+/**
+ * Data structure for each client connected to the CORE service.
+ */
+struct GSC_Client
+{
+  /**
+   * Clients are kept in a linked list.
+   */
+  struct GSC_Client *next;
+
+  /**
+   * Clients are kept in a linked list.
+   */
+  struct GSC_Client *prev;
+
+  /**
+   * Handle for the client with the server API.
+   */
+  struct GNUNET_SERVICE_Client *client;
+
+  /**
+   * Message queue to talk to @e client.
+   */
+  struct GNUNET_MQ_Handle *mq;
+  
+  /**
+   * Array of the types of messages this peer cares
+   * about (with @e tcnt entries).  Allocated as part
+   * of this client struct, do not free!
+   */
+  uint16_t *types;
+  
+  /**
+   * Map of peer identities to active transmission requests of this
+   * client to the peer (of type `struct GSC_ClientActiveRequest`).
+   */
+  struct GNUNET_CONTAINER_MultiPeerMap *requests;
+
+  /**
+   * Map containing all peers that this client knows we're connected to.
+   */
+  struct GNUNET_CONTAINER_MultiPeerMap *connectmap;
+
+  /**
+   * Options for messages this client cares about,
+   * see GNUNET_CORE_OPTION_ values.
+   */
+  uint32_t options;
+
+  /**
+   * Number of types of incoming messages this client
+   * specifically cares about.  Size of the @e types array.
+   */
+  unsigned int tcnt;
+
+};
+
 
 /**
  * Our identity.
@@ -49,9 +113,739 @@ const struct GNUNET_CONFIGURATION_Handle *GSC_cfg;
 struct GNUNET_STATISTICS_Handle *GSC_stats;
 
 /**
- * Handle to the server of the core service.
+ * Big "or" of all client options.
+ */
+static uint32_t all_client_options;
+
+/**
+ * Head of linked list of our clients.
+ */
+static struct GSC_Client *client_head;
+
+/**
+ * Tail of linked list of our clients.
+ */
+static struct GSC_Client *client_tail;
+
+
+/**
+ * Test if the client is interested in messages of the given type.
+ *
+ * @param type message type
+ * @param c client to test
+ * @return #GNUNET_YES if @a c is interested, #GNUNET_NO if not.
+ */
+static int
+type_match (uint16_t type,
+            struct GSC_Client *c)
+{
+  if ( (0 == c->tcnt) &&
+       (0 != c->options) )
+    return GNUNET_YES;          /* peer without handlers and inbound/outbond
+                                   callbacks matches ALL */
+  if (NULL == c->types)
+    return GNUNET_NO;
+  for (unsigned int i = 0; i < c->tcnt; i++)
+    if (type == c->types[i])
+      return GNUNET_YES;
+  return GNUNET_NO;
+}
+
+
+/**
+ * Check #GNUNET_MESSAGE_TYPE_CORE_INIT request.
+ *
+ * @param cls client that sent #GNUNET_MESSAGE_TYPE_CORE_INIT
+ * @param im the `struct InitMessage` 
+ * @return #GNUNET_OK if @a im is well-formed
  */
-static struct GNUNET_SERVER_Handle *GSC_server;
+static int
+check_client_init (void *cls,
+                   const struct InitMessage *im)
+{
+  return GNUNET_OK;
+}
+
+
+/**
+ * Handle #GNUNET_MESSAGE_TYPE_CORE_INIT request.
+ *
+ * @param cls client that sent #GNUNET_MESSAGE_TYPE_CORE_INIT
+ * @param im the `struct InitMessage` 
+ */
+static void
+handle_client_init (void *cls,
+                    const struct InitMessage *im)
+{
+  struct GSC_Client *c = cls;
+  struct GNUNET_MQ_Envelope *env;
+  struct InitReplyMessage *irm;
+  uint16_t msize;
+  const uint16_t *types;
+
+  /* check that we don't have an entry already */
+  msize = ntohs (im->header.size) - sizeof (struct InitMessage);
+  types = (const uint16_t *) &im[1];
+  c->tcnt = msize / sizeof (uint16_t);
+  c->options = ntohl (im->options);
+  all_client_options |= c->options;
+  c->types = GNUNET_malloc (msize);
+  c->connectmap = GNUNET_CONTAINER_multipeermap_create (16,
+                                                        GNUNET_NO);
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multipeermap_put (c->connectmap,
+                                                    &GSC_my_identity,
+                                                    NULL,
+                                                    GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+  for (unsigned int i = 0; i < c->tcnt; i++)
+    c->types[i] = ntohs (types[i]);
+  GSC_TYPEMAP_add (c->types,
+                   c->tcnt);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client connecting to core service is interested in %u message types\n",
+              (unsigned int) c->tcnt);
+  /* send init reply message */
+  env = GNUNET_MQ_msg (irm,
+                       GNUNET_MESSAGE_TYPE_CORE_INIT_REPLY);
+  irm->reserved = htonl (0);
+  irm->my_identity = GSC_my_identity;
+  GNUNET_MQ_send (c->mq,
+                  env);
+  GSC_SESSIONS_notify_client_about_sessions (c);
+  GNUNET_SERVICE_client_continue (c->client);
+}
+
+
+/**
+ * We will never be ready to transmit the given message in (disconnect
+ * or invalid request).  Frees resources associated with @a car.  We
+ * don't explicitly tell the client, he'll learn with the disconnect
+ * (or violated the protocol).
+ *
+ * @param car request that now permanently failed; the
+ *        responsibility for the handle is now returned
+ *        to CLIENTS (SESSIONS is done with it).
+ * @param drop_client #GNUNET_YES if the client violated the protocol
+ *        and we should thus drop the connection
+ */
+void
+GSC_CLIENTS_reject_request (struct GSC_ClientActiveRequest *car,
+                            int drop_client)
+{
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multipeermap_remove (car->
+                                                       client_handle->requests,
+                                                       &car->target,
+                                                       car));
+  if (GNUNET_YES == drop_client)
+    GNUNET_SERVICE_client_drop (car->client_handle->client);
+  GNUNET_free (car);
+}
+
+
+/**
+ * Tell a client that we are ready to receive the message.
+ *
+ * @param car request that is now ready; the responsibility
+ *        for the handle remains shared between CLIENTS
+ *        and SESSIONS after this call.
+ */
+void
+GSC_CLIENTS_solicit_request (struct GSC_ClientActiveRequest *car)
+{
+  struct GSC_Client *c;
+  struct GNUNET_MQ_Envelope *env;
+  struct SendMessageReady *smr;
+  struct GNUNET_TIME_Relative delay;
+  struct GNUNET_TIME_Relative left;
+
+  c = car->client_handle;
+  if (GNUNET_YES !=
+      GNUNET_CONTAINER_multipeermap_contains (c->connectmap,
+                                              &car->target))
+  {
+    /* connection has gone down since, drop request */
+    GNUNET_assert (0 !=
+                   memcmp (&car->target,
+                           &GSC_my_identity,
+                           sizeof (struct GNUNET_PeerIdentity)));
+    GSC_SESSIONS_dequeue_request (car);
+    GSC_CLIENTS_reject_request (car,
+                                GNUNET_NO);
+    return;
+  }
+  delay = GNUNET_TIME_absolute_get_duration (car->received_time);
+  left = GNUNET_TIME_absolute_get_duration (car->deadline);
+  if (delay.rel_value_us > GNUNET_CONSTANTS_LATENCY_WARN.rel_value_us)
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Client waited %s for permission to transmit to `%s'%s (priority %u)\n",
+                GNUNET_STRINGS_relative_time_to_string (delay,
+                                                        GNUNET_YES),
+                GNUNET_i2s (&car->target),
+                (0 == left.rel_value_us)
+                ? " (past deadline)"
+                : "",
+                car->priority);
+  env = GNUNET_MQ_msg (smr,
+                       GNUNET_MESSAGE_TYPE_CORE_SEND_READY);
+  smr->size = htons (car->msize);
+  smr->smr_id = car->smr_id;
+  smr->peer = car->target;
+  GNUNET_MQ_send (c->mq,
+                  env);
+}
+
+
+/**
+ * Handle #GNUNET_MESSAGE_TYPE_CORE_SEND_REQUEST message.
+ *
+ * @param cls client that sent a #GNUNET_MESSAGE_TYPE_CORE_SEND_REQUEST
+ * @param req the `struct SendMessageRequest`
+ */
+static void
+handle_client_send_request (void *cls,
+                            const struct SendMessageRequest *req)
+{
+  struct GSC_Client *c = cls;
+  struct GSC_ClientActiveRequest *car;
+  int is_loopback;
+
+  if (NULL == c->requests)
+    c->requests = GNUNET_CONTAINER_multipeermap_create (16,
+                                                        GNUNET_NO);
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client asked for transmission to `%s'\n",
+              GNUNET_i2s (&req->peer));
+  is_loopback =
+      (0 ==
+       memcmp (&req->peer,
+               &GSC_my_identity,
+               sizeof (struct GNUNET_PeerIdentity)));
+  if ((! is_loopback) &&
+      (GNUNET_YES !=
+       GNUNET_CONTAINER_multipeermap_contains (c->connectmap,
+                                               &req->peer)))
+  {
+    /* neighbour must have disconnected since request was issued,
+     * ignore (client will realize it once it processes the
+     * disconnect notification) */
+    GNUNET_STATISTICS_update (GSC_stats,
+                              gettext_noop
+                              ("# send requests dropped (disconnected)"), 1,
+                              GNUNET_NO);
+    GNUNET_SERVICE_client_continue (c->client);
+    return;
+  }
+
+  car = GNUNET_CONTAINER_multipeermap_get (c->requests,
+                                           &req->peer);
+  if (NULL == car)
+  {
+    /* create new entry */
+    car = GNUNET_new (struct GSC_ClientActiveRequest);
+    GNUNET_assert (GNUNET_OK ==
+                   GNUNET_CONTAINER_multipeermap_put (c->requests,
+                                                      &req->peer,
+                                                      car,
+                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST));
+    car->client_handle = c;
+  }
+  else
+  {
+    /* dequeue and recycle memory from pending request, there can only
+       be at most one per client and peer */
+    GNUNET_STATISTICS_update (GSC_stats,
+                              gettext_noop ("# dequeuing CAR (duplicate request)"),
+                              1,
+                              GNUNET_NO);
+    GSC_SESSIONS_dequeue_request (car);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Transmission request to `%s' was a duplicate!\n",
+                GNUNET_i2s (&req->peer));
+  }
+  car->target = req->peer;
+  car->received_time = GNUNET_TIME_absolute_get ();
+  car->deadline = GNUNET_TIME_absolute_ntoh (req->deadline);
+  car->priority = (enum GNUNET_CORE_Priority) ntohl (req->priority);
+  car->msize = ntohs (req->size);
+  car->smr_id = req->smr_id;
+  car->was_solicited = GNUNET_NO;
+  GNUNET_SERVICE_client_continue (c->client);
+  if (is_loopback)
+  {
+    /* loopback, satisfy immediately */
+    GSC_CLIENTS_solicit_request (car);
+    return;
+  }
+  GSC_SESSIONS_queue_request (car);
+}
+
+
+/**
+ * Closure for the #client_tokenizer_callback().
+ */
+struct TokenizerContext
+{
+
+  /**
+   * Active request handle for the message.
+   */
+  struct GSC_ClientActiveRequest *car;
+
+  /**
+   * How important is this message.
+   */
+  enum GNUNET_CORE_Priority priority;
+
+  /**
+   * Is corking allowed (set only once we have the real message).
+   */
+  int cork;
+
+};
+
+
+/**
+ * Functions with this signature are called whenever a complete
+ * message is received by the tokenizer.  Used by
+ * #handle_client_send() for dispatching messages from clients to
+ * either the SESSION subsystem or other CLIENT (for loopback).
+ *
+ * @param cls reservation request (`struct TokenizerContext`)
+ * @param message the actual message
+ */
+static int
+tokenized_cb (void *cls,
+              const struct GNUNET_MessageHeader *message)
+{
+  struct TokenizerContext *tc = cls;
+  struct GSC_ClientActiveRequest *car = tc->car;
+  char buf[92];
+
+  GNUNET_snprintf (buf,
+                   sizeof (buf),
+                   gettext_noop ("# bytes of messages of type %u received"),
+                   (unsigned int) ntohs (message->type));
+  GNUNET_STATISTICS_update (GSC_stats,
+                            buf,
+                            ntohs (message->size),
+                            GNUNET_NO);
+  if (0 ==
+      memcmp (&car->target,
+              &GSC_my_identity,
+              sizeof (struct GNUNET_PeerIdentity)))
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Delivering message of type %u to myself\n",
+                ntohs (message->type));
+    GSC_CLIENTS_deliver_message (&GSC_my_identity,
+                                 message,
+                                 ntohs (message->size),
+                                 GNUNET_CORE_OPTION_SEND_FULL_OUTBOUND);
+    GSC_CLIENTS_deliver_message (&GSC_my_identity,
+                                 message,
+                                 sizeof (struct GNUNET_MessageHeader),
+                                 GNUNET_CORE_OPTION_SEND_HDR_OUTBOUND);
+    GSC_CLIENTS_deliver_message (&GSC_my_identity,
+                                 message,
+                                 ntohs (message->size),
+                                 GNUNET_CORE_OPTION_SEND_FULL_INBOUND);
+    GSC_CLIENTS_deliver_message (&GSC_my_identity,
+                                 message,
+                                 sizeof (struct GNUNET_MessageHeader),
+                                 GNUNET_CORE_OPTION_SEND_HDR_INBOUND);
+  }
+  else
+  {
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Delivering message of type %u and size %u to %s\n",
+                ntohs (message->type),
+                ntohs (message->size),
+                GNUNET_i2s (&car->target));
+    GSC_CLIENTS_deliver_message (&car->target,
+                                 message,
+                                 ntohs (message->size),
+                                 GNUNET_CORE_OPTION_SEND_FULL_OUTBOUND);
+    GSC_CLIENTS_deliver_message (&car->target,
+                                 message,
+                                 sizeof (struct GNUNET_MessageHeader),
+                                 GNUNET_CORE_OPTION_SEND_HDR_OUTBOUND);
+    GSC_SESSIONS_transmit (car,
+                           message,
+                           tc->cork,
+                           tc->priority);
+  }
+  return GNUNET_OK;
+}
+
+
+/**
+ * Check #GNUNET_MESSAGE_TYPE_CORE_SEND request.
+ *
+ * @param cls the `struct GSC_Client`
+ * @param sm the `struct SendMessage`
+ * @return #GNUNET_OK if @a sm is well-formed
+ */
+static int
+check_client_send (void *cls,
+                   const struct SendMessage *sm)
+{
+  return GNUNET_OK;
+}
+
+
+/**
+ * Handle #GNUNET_MESSAGE_TYPE_CORE_SEND request.
+ *
+ * @param cls the `struct GSC_Client`
+ * @param sm the `struct SendMessage`
+ */
+static void
+handle_client_send (void *cls,
+                    const struct SendMessage *sm)
+{
+  struct GSC_Client *c = cls;
+  struct TokenizerContext tc;
+  uint16_t msize;
+  struct GNUNET_TIME_Relative delay;
+  struct GNUNET_MessageStreamTokenizer *mst;
+
+  msize = ntohs (sm->header.size) - sizeof (struct SendMessage);
+  GNUNET_break (0 == ntohl (sm->reserved));
+  tc.car = GNUNET_CONTAINER_multipeermap_get (c->requests,
+                                              &sm->peer);
+  if (NULL == tc.car)
+  {
+    /* Must have been that we first approved the request, then got disconnected
+     * (which triggered removal of the 'car') and now the client gives us a message
+     * just *before* the client learns about the disconnect.  Theoretically, we
+     * might also now be *again* connected.  So this can happen (but should be
+     * rare).  If it does happen, the message is discarded. */
+    GNUNET_STATISTICS_update (GSC_stats,
+                              gettext_noop ("# messages discarded (session disconnected)"),
+                              1,
+                              GNUNET_NO);
+    GNUNET_SERVICE_client_continue (c->client);
+    return;
+  }
+  delay = GNUNET_TIME_absolute_get_duration (tc.car->received_time);
+  tc.cork = ntohl (sm->cork);
+  tc.priority = (enum GNUNET_CORE_Priority) ntohl (sm->priority);
+  if (delay.rel_value_us > GNUNET_CONSTANTS_LATENCY_WARN.rel_value_us)
+    GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+                "Client waited %s for transmission of %u bytes to `%s'%s\n",
+                GNUNET_STRINGS_relative_time_to_string (delay,
+                                                        GNUNET_YES),
+                msize,
+                GNUNET_i2s (&sm->peer),
+                tc.cork ? " (cork)" : " (uncorked)");
+  else
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Client waited %s for transmission of %u bytes to `%s'%s\n",
+                GNUNET_STRINGS_relative_time_to_string (delay,
+                                                        GNUNET_YES),
+                msize,
+                GNUNET_i2s (&sm->peer),
+                tc.cork ? " (cork)" : " (uncorked)");
+
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multipeermap_remove (c->requests,
+                                                       &sm->peer,
+                                                       tc.car));
+  mst = GNUNET_MST_create (&tokenized_cb,
+                           &tc);
+  GNUNET_MST_from_buffer (mst,
+                          (const char *) &sm[1],
+                          msize,
+                          GNUNET_YES,
+                          GNUNET_NO);
+  GNUNET_MST_destroy (mst);
+  GSC_SESSIONS_dequeue_request (tc.car);
+  GNUNET_free (tc.car);
+  GNUNET_SERVICE_client_continue (c->client);
+}
+
+
+/**
+ * Free client request records.
+ *
+ * @param cls NULL
+ * @param key identity of peer for which this is an active request
+ * @param value the `struct GSC_ClientActiveRequest` to free
+ * @return #GNUNET_YES (continue iteration)
+ */
+static int
+destroy_active_client_request (void *cls,
+                               const struct GNUNET_PeerIdentity *key,
+                               void *value)
+{
+  struct GSC_ClientActiveRequest *car = value;
+
+  GNUNET_assert (GNUNET_YES ==
+                 GNUNET_CONTAINER_multipeermap_remove (car->
+                                                       client_handle->requests,
+                                                       &car->target,
+                                                       car));
+  GSC_SESSIONS_dequeue_request (car);
+  GNUNET_free (car);
+  return GNUNET_YES;
+}
+
+
+/**
+ * A client connected, set up.
+ *
+ * @param cls closure
+ * @param client identification of the client
+ * @param mq message queue to talk to @a client
+ * @return our client handle
+ */
+static void *
+client_connect_cb (void *cls,
+                   struct GNUNET_SERVICE_Client *client,
+                   struct GNUNET_MQ_Handle *mq)
+{
+  struct GSC_Client *c;
+  
+  c = GNUNET_new (struct GSC_Client);
+  c->client = client;
+  c->mq = mq;
+  GNUNET_CONTAINER_DLL_insert (client_head,
+                               client_tail,
+                               c);
+  return c;
+}
+
+
+/**
+ * A client disconnected, clean up.
+ *
+ * @param cls closure
+ * @param client identification of the client
+ * @param app_ctx our `struct GST_Client` for @a client
+ */
+static void
+client_disconnect_cb (void *cls,
+                      struct GNUNET_SERVICE_Client *client,
+                      void *app_ctx)
+{
+  struct GSC_Client *c = app_ctx;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Client %p has disconnected from core service.\n",
+              client);
+  GNUNET_CONTAINER_DLL_remove (client_head,
+                               client_tail,
+                               c);
+  if (NULL != c->requests)
+  {
+    GNUNET_CONTAINER_multipeermap_iterate (c->requests,
+                                           &destroy_active_client_request,
+                                           NULL);
+    GNUNET_CONTAINER_multipeermap_destroy (c->requests);
+  }
+  if (NULL != c->connectmap)
+  {
+    GNUNET_CONTAINER_multipeermap_destroy (c->connectmap);
+    c->connectmap = NULL;
+  }
+  if (NULL != c->types)
+  {
+    GSC_TYPEMAP_remove (c->types,
+                        c->tcnt);
+    GNUNET_free (c->types);
+  }
+  GNUNET_free (c);
+
+  /* recalculate 'all_client_options' */
+  all_client_options = 0;
+  for (c = client_head; NULL != c ; c = c->next)
+    all_client_options |= c->options;
+}
+
+
+/**
+ * Notify a particular client about a change to existing connection to
+ * one of our neighbours (check if the client is interested).  Called
+ * from #GSC_SESSIONS_notify_client_about_sessions().
+ *
+ * @param client client to notify
+ * @param neighbour identity of the neighbour that changed status
+ * @param tmap_old previous type map for the neighbour, NULL for connect
+ * @param tmap_new updated type map for the neighbour, NULL for disconnect
+ */
+void
+GSC_CLIENTS_notify_client_about_neighbour (struct GSC_Client *client,
+                                           const struct GNUNET_PeerIdentity *neighbour,
+                                           const struct GSC_TypeMap *tmap_old,
+                                           const struct GSC_TypeMap *tmap_new)
+{
+  struct GNUNET_MQ_Envelope *env;
+  int old_match;
+  int new_match;
+
+  old_match = GSC_TYPEMAP_test_match (tmap_old,
+                                      client->types,
+                                      client->tcnt);
+  new_match = GSC_TYPEMAP_test_match (tmap_new,
+                                      client->types,
+                                      client->tcnt);
+  if (old_match == new_match)
+  {
+    GNUNET_assert (old_match ==
+                   GNUNET_CONTAINER_multipeermap_contains (client->connectmap,
+                                                           neighbour));
+    return;                     /* no change */
+  }
+  if (GNUNET_NO == old_match)
+  {
+    struct ConnectNotifyMessage *cnm;
+
+    /* send connect */
+    GNUNET_assert (GNUNET_NO ==
+                   GNUNET_CONTAINER_multipeermap_contains (client->connectmap,
+                                                           neighbour));
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CONTAINER_multipeermap_put (client->connectmap,
+                                                      neighbour,
+                                                      NULL,
+                                                      GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY));
+    env = GNUNET_MQ_msg (cnm,
+                         GNUNET_MESSAGE_TYPE_CORE_NOTIFY_CONNECT);
+    cnm->reserved = htonl (0);
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Sending NOTIFY_CONNECT message to client.\n");
+    cnm->peer = *neighbour;
+    GNUNET_MQ_send (client->mq,
+                    env);
+  }
+  else
+  {
+    struct DisconnectNotifyMessage *dcm;
+
+  /* send disconnect */
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CONTAINER_multipeermap_contains (client->connectmap,
+                                                           neighbour));
+    GNUNET_assert (GNUNET_YES ==
+                   GNUNET_CONTAINER_multipeermap_remove (client->connectmap,
+                                                         neighbour,
+                                                         NULL));
+    env = GNUNET_MQ_msg (dcm,
+                         GNUNET_MESSAGE_TYPE_CORE_NOTIFY_DISCONNECT);
+    dcm->reserved = htonl (0);
+    dcm->peer = *neighbour;
+    GNUNET_MQ_send (client->mq,
+                    env);
+  }
+}
+
+
+/**
+ * Notify all clients about a change to existing session.
+ * Called from SESSIONS whenever there is a change in sessions
+ * or types processed by the respective peer.
+ *
+ * @param neighbour identity of the neighbour that changed status
+ * @param tmap_old previous type map for the neighbour, NULL for connect
+ * @param tmap_new updated type map for the neighbour, NULL for disconnect
+ */
+void
+GSC_CLIENTS_notify_clients_about_neighbour (const struct GNUNET_PeerIdentity *neighbour,
+                                            const struct GSC_TypeMap *tmap_old,
+                                            const struct GSC_TypeMap *tmap_new)
+{
+  struct GSC_Client *c;
+
+  for (c = client_head; NULL != c; c = c->next)
+    GSC_CLIENTS_notify_client_about_neighbour (c,
+                                               neighbour,
+                                               tmap_old,
+                                               tmap_new);
+}
+
+
+/**
+ * Deliver P2P message to interested clients.  Caller must have checked
+ * that the sending peer actually lists the given message type as one
+ * of its types.
+ *
+ * @param sender peer who sent us the message
+ * @param msg the message
+ * @param msize number of bytes to transmit
+ * @param options options for checking which clients should
+ *        receive the message
+ */
+void
+GSC_CLIENTS_deliver_message (const struct GNUNET_PeerIdentity *sender,
+                             const struct GNUNET_MessageHeader *msg,
+                             uint16_t msize,
+                             uint32_t options)
+{
+  size_t size = msize + sizeof (struct NotifyTrafficMessage);
+
+  if (size >= GNUNET_SERVER_MAX_MESSAGE_SIZE)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  if (! ( (0 != (all_client_options & options)) ||
+          (0 != (options & GNUNET_CORE_OPTION_SEND_FULL_INBOUND)) ))
+    return; /* no client cares about this message notification */
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "Core service passes message from `%s' of type %u to client.\n",
+              GNUNET_i2s (sender),
+              (unsigned int) ntohs (msg->type));
+  GSC_SESSIONS_add_to_typemap (sender,
+                               ntohs (msg->type));
+
+  for (struct GSC_Client *c = client_head; NULL != c; c = c->next)
+  {
+    struct GNUNET_MQ_Envelope *env;
+    struct NotifyTrafficMessage *ntm;
+    uint16_t mtype;
+    int tm;
+
+    tm = type_match (ntohs (msg->type),
+                     c);
+    if (! ( (0 != (c->options & options)) ||
+            ( (0 != (options & GNUNET_CORE_OPTION_SEND_FULL_INBOUND)) &&
+              (GNUNET_YES == tm) ) ) )
+      continue;  /* neither options nor type match permit the message */
+    if ( (0 != (options & GNUNET_CORE_OPTION_SEND_HDR_INBOUND)) &&
+         ( (0 != (c->options & GNUNET_CORE_OPTION_SEND_FULL_INBOUND)) ||
+           (GNUNET_YES == tm) ) )
+      continue;
+    if ( (0 != (options & GNUNET_CORE_OPTION_SEND_HDR_OUTBOUND)) &&
+         (0 != (c->options & GNUNET_CORE_OPTION_SEND_FULL_OUTBOUND)) )
+      continue;
+    GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+                "Sending %u message with %u bytes to client interested in messages of type %u.\n",
+                options,
+                ntohs (msg->size),
+                (unsigned int) ntohs (msg->type));
+
+    if (0 != (options & (GNUNET_CORE_OPTION_SEND_FULL_INBOUND | GNUNET_CORE_OPTION_SEND_HDR_INBOUND)))
+      mtype = GNUNET_MESSAGE_TYPE_CORE_NOTIFY_INBOUND;
+    else
+      mtype = GNUNET_MESSAGE_TYPE_CORE_NOTIFY_OUTBOUND;
+    env = GNUNET_MQ_msg_extra (ntm,
+                               msize,
+                               mtype);
+    ntm->peer = *sender;
+    GNUNET_memcpy (&ntm[1],
+                   msg,
+                   msize);
+
+    GNUNET_assert ( (0 == (c->options & GNUNET_CORE_OPTION_SEND_FULL_INBOUND)) ||
+                    (GNUNET_YES != tm) ||
+                    (GNUNET_YES ==
+                     GNUNET_CONTAINER_multipeermap_contains (c->connectmap,
+                                                             sender)) );
+    GNUNET_MQ_send (c->mq,
+                    env);
+  }  
+}
 
 
 /**
@@ -63,9 +857,12 @@ static struct GNUNET_SERVER_Handle *GSC_server;
 static void
 shutdown_task (void *cls)
 {
+  struct GSC_Client *c;
+
   GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
               "Core service shutting down.\n");
-  GSC_CLIENTS_done ();
+  while (NULL != (c = client_head))
+    GNUNET_SERVICE_client_drop (c->client);
   GSC_SESSIONS_done ();
   GSC_KX_done ();
   GSC_TYPEMAP_done ();
@@ -80,22 +877,41 @@ shutdown_task (void *cls)
 
 
 /**
+ * Handle #GNUNET_MESSAGE_TYPE_CORE_MONITOR_PEERS request.  For this
+ * request type, the client does not have to have transmitted an INIT
+ * request.  All current peers are returned, regardless of which
+ * message types they accept.
+ *
+ * @param cls client sending the iteration request
+ * @param message iteration request message
+ */
+static void
+handle_client_monitor_peers (void *cls,
+                             const struct GNUNET_MessageHeader *message)
+{
+  struct GSC_Client *c = cls;
+  
+  GNUNET_SERVICE_client_continue (c->client);
+  GSC_KX_handle_client_monitor_peers (c->mq);
+}
+
+
+/**
  * Initiate core service.
  *
  * @param cls closure
- * @param server the initialized server
  * @param c configuration to use
+ * @param service the initialized service
  */
 static void
 run (void *cls,
-     struct GNUNET_SERVER_Handle *server,
-     const struct GNUNET_CONFIGURATION_Handle *c)
+     const struct GNUNET_CONFIGURATION_Handle *c,
+     struct GNUNET_SERVICE_Handle *service)
 {
   struct GNUNET_CRYPTO_EddsaPrivateKey *pk;
   char *keyfile;
 
   GSC_cfg = c;
-  GSC_server = server;
   if (GNUNET_OK !=
       GNUNET_CONFIGURATION_get_value_filename (GSC_cfg,
                                                "PEER",
@@ -111,20 +927,18 @@ run (void *cls,
                                         GSC_cfg);
   GNUNET_SCHEDULER_add_shutdown (&shutdown_task,
                                  NULL);
-  GNUNET_SERVER_suspend (server);
+  GNUNET_SERVICE_suspend (service);
   GSC_TYPEMAP_init ();
   pk = GNUNET_CRYPTO_eddsa_key_create_from_file (keyfile);
   GNUNET_free (keyfile);
   GNUNET_assert (NULL != pk);
-  if (GNUNET_OK != GSC_KX_init (pk,
-                                server))
+  if (GNUNET_OK != GSC_KX_init (pk))
   {
     GNUNET_SCHEDULER_shutdown ();
     return;
   }
   GSC_SESSIONS_init ();
-  GSC_CLIENTS_init (GSC_server);
-  GNUNET_SERVER_resume (GSC_server);
+  GNUNET_SERVICE_resume (service);
   GNUNET_log (GNUNET_ERROR_TYPE_INFO,
               _("Core service of `%s' ready.\n"),
               GNUNET_i2s (&GSC_my_identity));
@@ -132,19 +946,32 @@ run (void *cls,
 
 
 /**
- * The main function for the transport service.
- *
- * @param argc number of arguments from the command line
- * @param argv command line arguments
- * @return 0 ok, 1 on error
+ * Define "main" method using service macro.
  */
-int
-main (int argc, char *const *argv)
-{
-  return (GNUNET_OK ==
-          GNUNET_SERVICE_run (argc, argv, "core",
-                              GNUNET_SERVICE_OPTION_NONE,
-                              &run, NULL)) ? 0 : 1;
-}
+GNUNET_SERVICE_MAIN
+("core",
+ GNUNET_SERVICE_OPTION_NONE,
+ &run,
+ &client_connect_cb,
+ &client_disconnect_cb,
+ NULL,
+ GNUNET_MQ_hd_var_size (client_init,
+                        GNUNET_MESSAGE_TYPE_CORE_INIT,
+                        struct InitMessage, 
+                        NULL),
+ GNUNET_MQ_hd_fixed_size (client_monitor_peers,
+                          GNUNET_MESSAGE_TYPE_CORE_MONITOR_PEERS,
+                          struct GNUNET_MessageHeader,
+                          NULL),
+ GNUNET_MQ_hd_fixed_size (client_send_request,
+                          GNUNET_MESSAGE_TYPE_CORE_SEND_REQUEST,
+                          struct SendMessageRequest,
+                          NULL),
+ GNUNET_MQ_hd_var_size (client_send,
+                        GNUNET_MESSAGE_TYPE_CORE_SEND,
+                        struct SendMessage,
+                        NULL),
+ GNUNET_MQ_handler_end ());
+
 
 /* end of gnunet-service-core.c */