1 files changed, 629 insertions, 0 deletions

diff --git a/src/service/dht/plugin_dhtu_gnunet.c b/src/service/dht/plugin_dhtu_gnunet.c
new file mode 100644
index 000000000..1314f789a
--- /dev/null
+++ b/src/service/dht/plugin_dhtu_gnunet.c
@@ -0,0 +1,629 @@
+/*
+     This file is part of GNUnet
+     Copyright (C) 2021 GNUnet e.V.
+
+     GNUnet is free software: you can redistribute it and/or modify it
+     under the terms of the GNU Affero General Public License as published
+     by the Free Software Foundation, either version 3 of the License,
+     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
+     Affero General Public License for more details.
+
+     You should have received a copy of the GNU Affero General Public License
+     along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+     SPDX-License-Identifier: AGPL3.0-or-later
+ */
+
+/**
+ * @author Christian Grothoff
+ *
+ * @file plugin_dhtu_gnunet.c
+ * @brief plain IP based DHT network underlay
+ */
+#include "platform.h"
+#include "gnunet_dhtu_plugin.h"
+#include "gnunet_core_service.h"
+#include "gnunet_transport_application_service.h"
+#include "gnunet_hello_uri_lib.h"
+#include "gnunet_peerstore_service.h"
+#include "gnunet_nse_service.h"
+#include "plugin_dhtu_gnunet.h"
+
+/**
+ * Opaque handle that the underlay offers for our address to be used when
+ * sending messages to another peer.
+ */
+struct GNUNET_DHTU_Source
+{
+
+  /**
+   * Application context for this source.
+   */
+  void *app_ctx;
+
+};
+
+
+/**
+ * Opaque handle that the underlay offers for the target peer when sending
+ * messages to another peer.
+ */
+struct GNUNET_DHTU_Target
+{
+
+  /**
+   * Application context for this target.
+   */
+  void *app_ctx;
+
+  /**
+   * Our plugin with its environment.
+   */
+  struct Plugin *plugin;
+
+  /**
+   * CORE MQ to send messages to this peer.
+   */
+  struct GNUNET_MQ_Handle *mq;
+
+  /**
+   * Head of preferences expressed for this target.
+   */
+  struct GNUNET_DHTU_PreferenceHandle *ph_head;
+
+  /**
+   * Tail of preferences expressed for this target.
+   */
+  struct GNUNET_DHTU_PreferenceHandle *ph_tail;
+
+  /**
+   * Transport suggest handle.
+   */
+  struct GNUNET_TRANSPORT_ApplicationSuggestHandle *ash;
+
+  /**
+   * Identity of this peer.
+   */
+  struct GNUNET_PeerIdentity pid;
+
+  /**
+   * Preference counter, length of the @a ph_head DLL.
+   */
+  unsigned int ph_count;
+
+};
+
+
+/**
+ * Opaque handle expressing a preference of the DHT to
+ * keep a particular target connected.
+ */
+struct GNUNET_DHTU_PreferenceHandle
+{
+  /**
+   * Kept in a DLL.
+   */
+  struct GNUNET_DHTU_PreferenceHandle *next;
+
+  /**
+   * Kept in a DLL.
+   */
+  struct GNUNET_DHTU_PreferenceHandle *prev;
+
+  /**
+   * Target a preference was expressed for.
+   */
+  struct GNUNET_DHTU_Target *target;
+};
+
+
+/**
+ * Closure for all plugin functions.
+ */
+struct Plugin
+{
+
+  /**
+   * Our "source" address. Traditional CORE API does not tell us which source
+   * it is, so they are all identical.
+   */
+  struct GNUNET_DHTU_Source src;
+
+  /**
+   * Callbacks into the DHT.
+   */
+  struct GNUNET_DHTU_PluginEnvironment *env;
+
+  /**
+   * Handle to the PEERSTORE service.
+   */
+  struct GNUNET_PEERSTORE_Handle *peerstore;
+
+  /**
+   * Handle to the CORE service.
+   */
+  struct GNUNET_CORE_Handle *core;
+
+  /**
+   * Handle to Transport service.
+   */
+  struct GNUNET_TRANSPORT_ApplicationHandle *transport;
+
+  /**
+   * Handle to the NSE service.
+   */
+  struct GNUNET_NSE_Handle *nse;
+
+  /**
+   * Our peerstore notification context.  We use notification
+   * to instantly learn about new peers as they are discovered.
+   */
+  struct GNUNET_PEERSTORE_Monitor *peerstore_notify;
+
+  /**
+   * Identity of this peer.
+   */
+  struct GNUNET_PeerIdentity my_identity;
+
+  /**
+   * Our private key.
+   */
+  struct GNUNET_CRYPTO_EddsaPrivateKey *my_priv;
+
+};
+
+
+// #include "../peerinfo-tool/gnunet-peerinfo_plugins.c"
+
+
+/**
+ * Request creation of a session with a peer at the given @a address.
+ *
+ * @param cls closure (internal context for the plugin)
+ * @param pid target identity of the peer to connect to
+ * @param address target address to connect to
+ */
+static void
+gnunet_try_connect (void *cls,
+                    const struct GNUNET_PeerIdentity *pid,
+                    const char *address)
+{
+  struct Plugin *plugin = cls;
+  enum GNUNET_NetworkType nt = 0;
+  char *addr;
+  const char *eou;
+  int pfx_len;
+
+  eou = strstr (address,
+                "://");
+  if (NULL == eou)
+  {
+    GNUNET_break (0);
+    return;
+  }
+  pfx_len = eou - address;
+  eou += 3;
+  GNUNET_asprintf (&addr,
+                   "%.*s-%s",
+                   pfx_len,
+                   address,
+                   eou);
+  GNUNET_TRANSPORT_application_validate (plugin->transport,
+                                         pid,
+                                         nt,
+                                         addr);
+  GNUNET_free (addr);
+}
+
+
+/**
+ * Request underlay to keep the connection to @a target alive if possible.
+ * Hold may be called multiple times to express a strong preference to
+ * keep a connection, say because a @a target is in multiple tables.
+ *
+ * @param cls closure
+ * @param target connection to keep alive
+ */
+static struct GNUNET_DHTU_PreferenceHandle *
+gnunet_hold (void *cls,
+             struct GNUNET_DHTU_Target *target)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_DHTU_PreferenceHandle *ph;
+
+  ph = GNUNET_new (struct GNUNET_DHTU_PreferenceHandle);
+  ph->target = target;
+  GNUNET_CONTAINER_DLL_insert (target->ph_head,
+                               target->ph_tail,
+                               ph);
+  target->ph_count++;
+  if (NULL != target->ash)
+    GNUNET_TRANSPORT_application_suggest_cancel (target->ash);
+  target->ash
+    = GNUNET_TRANSPORT_application_suggest (plugin->transport,
+                                            &target->pid,
+                                            GNUNET_MQ_PRIO_BEST_EFFORT,
+                                            GNUNET_BANDWIDTH_ZERO);
+  return ph;
+}
+
+
+/**
+ * Do no long request underlay to keep the connection alive.
+ *
+ * @param cls closure
+ * @param target connection to keep alive
+ */
+static void
+gnunet_drop (struct GNUNET_DHTU_PreferenceHandle *ph)
+{
+  struct GNUNET_DHTU_Target *target = ph->target;
+  struct Plugin *plugin = target->plugin;
+
+  GNUNET_CONTAINER_DLL_remove (target->ph_head,
+                               target->ph_tail,
+                               ph);
+  target->ph_count--;
+  GNUNET_free (ph);
+  if (NULL != target->ash)
+    GNUNET_TRANSPORT_application_suggest_cancel (target->ash);
+  if (0 == target->ph_count)
+    target->ash = NULL;
+  else
+    target->ash
+      = GNUNET_TRANSPORT_application_suggest (plugin->transport,
+                                              &target->pid,
+                                              GNUNET_MQ_PRIO_BEST_EFFORT,
+                                              GNUNET_BANDWIDTH_ZERO);
+}
+
+
+/**
+ * Send message to some other participant over the network.  Note that
+ * sending is not guaranteeing that the other peer actually received the
+ * message.  For any given @a target, the DHT must wait for the @a
+ * finished_cb to be called before calling send() again.
+ *
+ * @param cls closure (internal context for the plugin)
+ * @param target receiver identification
+ * @param msg message
+ * @param msg_size number of bytes in @a msg
+ * @param finished_cb function called once transmission is done
+ *        (not called if @a target disconnects, then only the
+ *         disconnect_cb is called).
+ * @param finished_cb_cls closure for @a finished_cb
+ */
+static void
+gnunet_send (void *cls,
+             struct GNUNET_DHTU_Target *target,
+             const void *msg,
+             size_t msg_size,
+             GNUNET_SCHEDULER_TaskCallback finished_cb,
+             void *finished_cb_cls)
+{
+  struct GNUNET_MQ_Envelope *env;
+  struct GNUNET_MessageHeader *cmsg;
+
+  env = GNUNET_MQ_msg_extra (cmsg,
+                             msg_size,
+                             GNUNET_MESSAGE_TYPE_DHT_CORE);
+  GNUNET_MQ_notify_sent (env,
+                         finished_cb,
+                         finished_cb_cls);
+  memcpy (&cmsg[1],
+          msg,
+          msg_size);
+  GNUNET_MQ_send (target->mq,
+                  env);
+}
+
+
+/**
+ * Method called whenever a given peer connects.
+ *
+ * @param cls closure
+ * @param peer peer identity this notification is about
+ * @return closure associated with @a peer. given to mq callbacks and
+ *         #GNUNET_CORE_DisconnectEventHandler
+ */
+static void *
+core_connect_cb (void *cls,
+                 const struct GNUNET_PeerIdentity *peer,
+                 struct GNUNET_MQ_Handle *mq)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_DHTU_Target *target;
+
+  target = GNUNET_new (struct GNUNET_DHTU_Target);
+  target->plugin = plugin;
+  target->mq = mq;
+  target->pid = *peer;
+  plugin->env->connect_cb (plugin->env->cls,
+                           target,
+                           &target->pid,
+                           &target->app_ctx);
+  return target;
+}
+
+
+/**
+ * Method called whenever a peer disconnects.
+ *
+ * @param cls closure
+ * @param peer peer identity this notification is about
+ * @param peer_cls closure associated with peer. given in
+ *        #GNUNET_CORE_ConnectEventHandler
+ */
+static void
+core_disconnect_cb (void *cls,
+                    const struct GNUNET_PeerIdentity *peer,
+                    void *peer_cls)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_DHTU_Target *target = peer_cls;
+
+  plugin->env->disconnect_cb (target->app_ctx);
+  if (NULL != target->ash)
+    GNUNET_TRANSPORT_application_suggest_cancel (target->ash);
+  GNUNET_free (target);
+}
+
+
+static void
+add_addr (void *cls,
+          const struct GNUNET_PeerIdentity *pid,
+          const char *addr)
+{
+  struct Plugin *plugin = cls;
+
+  GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
+              "peerinfo_cb addr %s\n",
+              addr);
+  plugin->env->address_add_cb (plugin->env->cls,
+                               addr,
+                               &plugin->src,
+                               &plugin->src.app_ctx);
+}
+
+
+/**
+ * Find the @a hello for our identity and then pass
+ * it to the DHT as a URL.  Note that we only
+ * add addresses, never remove them, due to limitations
+ * of the current peerinfo/core/transport APIs.
+ * This will change with TNG.
+ *
+ * @param cls a `struct Plugin`
+ * @param peer id of the peer, NULL for last call
+ * @param hello hello message for the peer (can be NULL)
+ * @param err_msg message
+ */
+static void
+peerinfo_cb (void *cls,
+             const struct GNUNET_PEERSTORE_Record *record,
+             const char *emsg)
+{
+  struct Plugin *plugin = cls;
+  struct GNUNET_HELLO_Builder *builder;
+  struct GNUNET_MessageHeader *hello;
+
+  hello = record->value;
+  if (NULL == hello)
+    return;
+  if (0 !=
+      GNUNET_memcmp (&record->peer,
+                     &plugin->my_identity))
+  {
+    GNUNET_PEERSTORE_monitor_next (plugin->peerstore_notify, 1);
+    return;
+  }
+  builder = GNUNET_HELLO_builder_from_msg (hello);
+  GNUNET_HELLO_builder_iterate (builder,
+                                add_addr,
+                                plugin);
+  GNUNET_HELLO_builder_free (builder);
+  GNUNET_PEERSTORE_monitor_next (plugin->peerstore_notify, 1);
+}
+
+static void
+error_cb (void *cls)
+{
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "Error in PEERSTORE monitoring\n");
+}
+
+
+static void
+sync_cb (void *cls)
+{
+  GNUNET_log (GNUNET_ERROR_TYPE_WARNING,
+              "Done with initial PEERSTORE iteration during monitoring\n");
+}
+
+
+/**
+ * Function called after #GNUNET_CORE_connect has succeeded (or failed
+ * for good).  Note that the private key of the peer is intentionally
+ * not exposed here; if you need it, your process should try to read
+ * the private key file directly (which should work if you are
+ * authorized...).  Implementations of this function must not call
+ * #GNUNET_CORE_disconnect (other than by scheduling a new task to
+ * do this later).
+ *
+ * @param cls closure
+ * @param my_identity ID of this peer, NULL if we failed
+ */
+static void
+core_init_cb (void *cls,
+              const struct GNUNET_PeerIdentity *my_identity)
+{
+  struct Plugin *plugin = cls;
+
+  plugin->my_identity = *my_identity;
+  plugin->peerstore_notify = GNUNET_PEERSTORE_monitor_start (plugin->env->cfg,
+                                                             GNUNET_YES,
+                                                             "peerstore",
+                                                             NULL,
+                                                             GNUNET_PEERSTORE_HELLO_KEY,
+                                                             &error_cb,
+                                                             NULL,
+                                                             &sync_cb,
+                                                             NULL,
+                                                             &peerinfo_cb,
+                                                             plugin);
+}
+
+
+/**
+ * Anything goes, always return #GNUNET_OK.
+ *
+ * @param cls unused
+ * @param msg message to check
+ * @return #GNUNET_OK if all is fine
+ */
+static int
+check_core_message (void *cls,
+                    const struct GNUNET_MessageHeader *msg)
+{
+  (void) cls;
+  (void) msg;
+  return GNUNET_OK;
+}
+
+
+/**
+ * Handle message from CORE for the DHT. Passes it to the
+ * DHT logic.
+ *
+ * @param cls a `struct GNUNET_DHTU_Target` of the sender
+ * @param msg the message we received
+ */
+static void
+handle_core_message (void *cls,
+                     const struct GNUNET_MessageHeader *msg)
+{
+  struct GNUNET_DHTU_Target *origin = cls;
+  struct Plugin *plugin = origin->plugin;
+
+  plugin->env->receive_cb (plugin->env->cls,
+                           &origin->app_ctx,
+                           &plugin->src.app_ctx,
+                           &msg[1],
+                           ntohs (msg->size) - sizeof (*msg));
+}
+
+
+/**
+ * Callback to call when network size estimate is updated.
+ *
+ * @param cls closure
+ * @param timestamp time when the estimate was received from the server (or created by the server)
+ * @param logestimate the log(Base 2) value of the current network size estimate
+ * @param std_dev standard deviation for the estimate
+ */
+static void
+nse_cb (void *cls,
+        struct GNUNET_TIME_Absolute timestamp,
+        double logestimate,
+        double std_dev)
+{
+  struct Plugin *plugin = cls;
+
+  plugin->env->network_size_cb (plugin->env->cls,
+                                timestamp,
+                                logestimate,
+                                std_dev);
+}
+
+
+/**
+ * Exit point from the plugin.
+ *
+ * @param cls closure (our `struct Plugin`)
+ * @return NULL
+ */
+void *
+DHTU_gnunet_done (void *cls)
+{
+  struct GNUNET_DHTU_PluginFunctions *api = cls;
+  struct Plugin *plugin = api->cls;
+
+  if (NULL != plugin->nse)
+    GNUNET_NSE_disconnect (plugin->nse);
+  plugin->env->network_size_cb (plugin->env->cls,
+                                GNUNET_TIME_UNIT_FOREVER_ABS,
+                                0.0,
+                                0.0);
+  if (NULL != plugin->core)
+    GNUNET_CORE_disconnect (plugin->core);
+  if (NULL != plugin->transport)
+    GNUNET_TRANSPORT_application_done (plugin->transport);
+  if (NULL != plugin->peerstore_notify)
+    GNUNET_PEERSTORE_monitor_stop (plugin->peerstore_notify);
+  if (NULL != plugin->peerstore)
+    GNUNET_PEERSTORE_disconnect (plugin->peerstore);
+  // GPI_plugins_unload ();
+  GNUNET_free (plugin->my_priv);
+  GNUNET_free (plugin);
+  GNUNET_free (api);
+  return NULL;
+}
+
+
+/**
+ * Entry point for the plugin.
+ *
+ * @param cls closure (the `struct GNUNET_DHTU_PluginEnvironment`)
+ * @return the plugin's API
+ */
+void *
+DHTU_gnunet_init (void *cls)
+{
+  struct GNUNET_DHTU_PluginEnvironment *env = cls;
+  struct GNUNET_DHTU_PluginFunctions *api;
+  struct Plugin *plugin;
+  struct GNUNET_MQ_MessageHandler handlers[] = {
+    GNUNET_MQ_hd_var_size (core_message,
+                           GNUNET_MESSAGE_TYPE_DHT_CORE,
+                           struct GNUNET_MessageHeader,
+                           NULL),
+    GNUNET_MQ_handler_end ()
+  };
+
+  plugin = GNUNET_new (struct Plugin);
+  plugin->my_priv = GNUNET_CRYPTO_eddsa_key_create_from_configuration (
+    env->cfg);
+  plugin->env = env;
+  api = GNUNET_new (struct GNUNET_DHTU_PluginFunctions);
+  api->cls = plugin;
+  api->try_connect = &gnunet_try_connect;
+  api->hold = &gnunet_hold;
+  api->drop = &gnunet_drop;
+  api->send = &gnunet_send;
+  plugin->peerstore = GNUNET_PEERSTORE_connect (env->cfg);
+  plugin->transport = GNUNET_TRANSPORT_application_init (env->cfg);
+  plugin->core = GNUNET_CORE_connect (env->cfg,
+                                      plugin,
+                                      &core_init_cb,
+                                      &core_connect_cb,
+                                      &core_disconnect_cb,
+                                      handlers);
+  plugin->nse = GNUNET_NSE_connect (env->cfg,
+                                    &nse_cb,
+                                    plugin);
+  if ( (NULL == plugin->transport) ||
+       (NULL == plugin->core) ||
+       (NULL == plugin->nse) )
+  {
+    GNUNET_break (0);
+    GNUNET_free (api);
+    DHTU_gnunet_done (plugin);
+    return NULL;
+  }
+  // GPI_plugins_load (env->cfg);
+  return api;
+}