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- /*
- This file is part of GNUnet.
- Copyright (C) 2012, 2013, 2017 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
- */
- /**
- * @file fs/gnunet-service-fs_cadet_server.c
- * @brief non-anonymous file-transfer
- * @author Christian Grothoff
- *
- * TODO:
- * - PORT is set to old application type, unsure if we should keep
- * it that way (fine for now)
- */
- #include "platform.h"
- #include "gnunet_constants.h"
- #include "gnunet_util_lib.h"
- #include "gnunet_cadet_service.h"
- #include "gnunet_protocols.h"
- #include "gnunet_applications.h"
- #include "gnunet-service-fs.h"
- #include "gnunet-service-fs_indexing.h"
- #include "gnunet-service-fs_cadet.h"
- /**
- * After how long do we termiante idle connections?
- */
- #define IDLE_TIMEOUT GNUNET_TIME_relative_multiply (GNUNET_TIME_UNIT_MINUTES, 2)
- /**
- * A message in the queue to be written to the cadet.
- */
- struct WriteQueueItem
- {
- /**
- * Kept in a DLL.
- */
- struct WriteQueueItem *next;
- /**
- * Kept in a DLL.
- */
- struct WriteQueueItem *prev;
- /**
- * Number of bytes of payload, allocated at the end of this struct.
- */
- size_t msize;
- };
- /**
- * Information we keep around for each active cadeting client.
- */
- struct CadetClient
- {
- /**
- * DLL
- */
- struct CadetClient *next;
- /**
- * DLL
- */
- struct CadetClient *prev;
- /**
- * Channel for communication.
- */
- struct GNUNET_CADET_Channel *channel;
- /**
- * Head of write queue.
- */
- struct WriteQueueItem *wqi_head;
- /**
- * Tail of write queue.
- */
- struct WriteQueueItem *wqi_tail;
- /**
- * Current active request to the datastore, if we have one pending.
- */
- struct GNUNET_DATASTORE_QueueEntry *qe;
- /**
- * Task that is scheduled to asynchronously terminate the connection.
- */
- struct GNUNET_SCHEDULER_Task *terminate_task;
- /**
- * Task that is scheduled to terminate idle connections.
- */
- struct GNUNET_SCHEDULER_Task *timeout_task;
- /**
- * Size of the last write that was initiated.
- */
- size_t reply_size;
- };
- /**
- * Listen port for incoming requests.
- */
- static struct GNUNET_CADET_Port *cadet_port;
- /**
- * Head of DLL of cadet clients.
- */
- static struct CadetClient *sc_head;
- /**
- * Tail of DLL of cadet clients.
- */
- static struct CadetClient *sc_tail;
- /**
- * Number of active cadet clients in the 'sc_*'-DLL.
- */
- static unsigned int sc_count;
- /**
- * Maximum allowed number of cadet clients.
- */
- static unsigned long long sc_count_max;
- /**
- * Task run to asynchronously terminate the cadet due to timeout.
- *
- * @param cls the 'struct CadetClient'
- */
- static void
- timeout_cadet_task (void *cls)
- {
- struct CadetClient *sc = cls;
- struct GNUNET_CADET_Channel *tun;
- sc->timeout_task = NULL;
- tun = sc->channel;
- sc->channel = NULL;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Timeout for inactive cadet client %p\n",
- sc);
- GNUNET_CADET_channel_destroy (tun);
- }
- /**
- * Reset the timeout for the cadet client (due to activity).
- *
- * @param sc client handle to reset timeout for
- */
- static void
- refresh_timeout_task (struct CadetClient *sc)
- {
- if (NULL != sc->timeout_task)
- GNUNET_SCHEDULER_cancel (sc->timeout_task);
- sc->timeout_task = GNUNET_SCHEDULER_add_delayed (IDLE_TIMEOUT,
- &timeout_cadet_task,
- sc);
- }
- /**
- * Check if we are done with the write queue, and if so tell CADET
- * that we are ready to read more.
- *
- * @param cls where to process the write queue
- */
- static void
- continue_writing (void *cls)
- {
- struct CadetClient *sc = cls;
- struct GNUNET_MQ_Handle *mq;
- mq = GNUNET_CADET_get_mq (sc->channel);
- if (0 != GNUNET_MQ_get_length (mq))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Write pending, waiting for it to complete\n");
- return;
- }
- refresh_timeout_task (sc);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Finished processing cadet request from client %p, ready to receive the next one\n",
- sc);
- GNUNET_CADET_receive_done (sc->channel);
- }
- /**
- * Process a datum that was stored in the datastore.
- *
- * @param cls closure with the `struct CadetClient` which sent the query
- * @param key key for the content
- * @param size number of bytes in @a data
- * @param data content stored
- * @param type type of the content
- * @param priority priority of the content
- * @param anonymity anonymity-level for the content
- * @param replication replication-level for the content
- * @param expiration expiration time for the content
- * @param uid unique identifier for the datum;
- * maybe 0 if no unique identifier is available
- */
- static void
- handle_datastore_reply (void *cls,
- const struct GNUNET_HashCode *key,
- size_t size,
- const void *data,
- enum GNUNET_BLOCK_Type type,
- uint32_t priority,
- uint32_t anonymity,
- uint32_t replication,
- struct GNUNET_TIME_Absolute expiration,
- uint64_t uid)
- {
- struct CadetClient *sc = cls;
- size_t msize = size + sizeof(struct CadetReplyMessage);
- struct GNUNET_MQ_Envelope *env;
- struct CadetReplyMessage *srm;
- sc->qe = NULL;
- if (NULL == data)
- {
- /* no result, this should not really happen, as for
- non-anonymous routing only peers that HAVE the
- answers should be queried; OTOH, this is not a
- hard error as we might have had the answer in the
- past and the user might have unindexed it. Hence
- we log at level "INFO" for now. */
- if (NULL == key)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_INFO,
- "Have no answer and the query was NULL\n");
- }
- else
- {
- GNUNET_log (GNUNET_ERROR_TYPE_INFO,
- "Have no answer for query `%s'\n",
- GNUNET_h2s (key));
- }
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop (
- "# queries received via CADET not answered"),
- 1,
- GNUNET_NO);
- continue_writing (sc);
- return;
- }
- if (GNUNET_BLOCK_TYPE_FS_ONDEMAND == type)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Performing on-demand encoding for query %s\n",
- GNUNET_h2s (key));
- if (GNUNET_OK !=
- GNUNET_FS_handle_on_demand_block (key,
- size,
- data,
- type,
- priority,
- anonymity,
- replication,
- expiration,
- uid,
- &handle_datastore_reply,
- sc))
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "On-demand encoding request failed\n");
- continue_writing (sc);
- }
- return;
- }
- if (msize > GNUNET_MAX_MESSAGE_SIZE)
- {
- GNUNET_break (0);
- continue_writing (sc);
- return;
- }
- GNUNET_break (GNUNET_BLOCK_TYPE_ANY != type);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Starting transmission of %u byte reply of type %d for query `%s' via cadet to %p\n",
- (unsigned int) size,
- (unsigned int) type,
- GNUNET_h2s (key),
- sc);
- env = GNUNET_MQ_msg_extra (srm,
- size,
- GNUNET_MESSAGE_TYPE_FS_CADET_REPLY);
- srm->type = htonl (type);
- srm->expiration = GNUNET_TIME_absolute_hton (expiration);
- GNUNET_memcpy (&srm[1],
- data,
- size);
- GNUNET_MQ_notify_sent (env,
- &continue_writing,
- sc);
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# Blocks transferred via cadet"),
- 1,
- GNUNET_NO);
- GNUNET_MQ_send (GNUNET_CADET_get_mq (sc->channel),
- env);
- }
- /**
- * Functions with this signature are called whenever a
- * complete query message is received.
- *
- * @param cls closure with the `struct CadetClient`
- * @param sqm the actual message
- */
- static void
- handle_request (void *cls,
- const struct CadetQueryMessage *sqm)
- {
- struct CadetClient *sc = cls;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Received query for `%s' via cadet from client %p\n",
- GNUNET_h2s (&sqm->query),
- sc);
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# queries received via cadet"),
- 1,
- GNUNET_NO);
- refresh_timeout_task (sc);
- sc->qe = GNUNET_DATASTORE_get_key (GSF_dsh,
- 0 /* next_uid */,
- false /* random */,
- &sqm->query,
- ntohl (sqm->type),
- 0 /* priority */,
- GSF_datastore_queue_size,
- &handle_datastore_reply,
- sc);
- if (NULL == sc->qe)
- {
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Queueing request with datastore failed (queue full?)\n");
- continue_writing (sc);
- }
- }
- /**
- * Functions of this type are called upon new cadet connection from other peers.
- *
- * @param cls the closure from GNUNET_CADET_connect
- * @param channel the channel representing the cadet
- * @param initiator the identity of the peer who wants to establish a cadet
- * with us; NULL on binding error
- * @return initial channel context (our `struct CadetClient`)
- */
- static void *
- connect_cb (void *cls,
- struct GNUNET_CADET_Channel *channel,
- const struct GNUNET_PeerIdentity *initiator)
- {
- struct CadetClient *sc;
- GNUNET_assert (NULL != channel);
- if (sc_count >= sc_count_max)
- {
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop (
- "# cadet client connections rejected"),
- 1,
- GNUNET_NO);
- GNUNET_CADET_channel_destroy (channel);
- return NULL;
- }
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# cadet connections active"),
- 1,
- GNUNET_NO);
- sc = GNUNET_new (struct CadetClient);
- sc->channel = channel;
- GNUNET_CONTAINER_DLL_insert (sc_head,
- sc_tail,
- sc);
- sc_count++;
- refresh_timeout_task (sc);
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Accepting inbound cadet connection from `%s' as client %p\n",
- GNUNET_i2s (initiator),
- sc);
- return sc;
- }
- /**
- * Function called by cadet when a client disconnects.
- * Cleans up our `struct CadetClient` of that channel.
- *
- * @param cls our `struct CadetClient`
- * @param channel channel of the disconnecting client
- * @param channel_ctx
- */
- static void
- disconnect_cb (void *cls,
- const struct GNUNET_CADET_Channel *channel)
- {
- struct CadetClient *sc = cls;
- struct WriteQueueItem *wqi;
- if (NULL == sc)
- return;
- sc->channel = NULL;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Terminating cadet connection with client %p\n",
- sc);
- GNUNET_STATISTICS_update (GSF_stats,
- gettext_noop ("# cadet connections active"), -1,
- GNUNET_NO);
- if (NULL != sc->terminate_task)
- GNUNET_SCHEDULER_cancel (sc->terminate_task);
- if (NULL != sc->timeout_task)
- GNUNET_SCHEDULER_cancel (sc->timeout_task);
- if (NULL != sc->qe)
- GNUNET_DATASTORE_cancel (sc->qe);
- while (NULL != (wqi = sc->wqi_head))
- {
- GNUNET_CONTAINER_DLL_remove (sc->wqi_head,
- sc->wqi_tail,
- wqi);
- GNUNET_free (wqi);
- }
- GNUNET_CONTAINER_DLL_remove (sc_head,
- sc_tail,
- sc);
- sc_count--;
- GNUNET_free (sc);
- }
- /**
- * Function called whenever an MQ-channel's transmission window size changes.
- *
- * The first callback in an outgoing channel will be with a non-zero value
- * and will mean the channel is connected to the destination.
- *
- * For an incoming channel it will be called immediately after the
- * #GNUNET_CADET_ConnectEventHandler, also with a non-zero value.
- *
- * @param cls Channel closure.
- * @param channel Connection to the other end (henceforth invalid).
- * @param window_size New window size. If the is more messages than buffer size
- * this value will be negative..
- */
- static void
- window_change_cb (void *cls,
- const struct GNUNET_CADET_Channel *channel,
- int window_size)
- {
- /* FIXME: could do flow control here... */
- }
- /**
- * Initialize subsystem for non-anonymous file-sharing.
- */
- void
- GSF_cadet_start_server ()
- {
- struct GNUNET_MQ_MessageHandler handlers[] = {
- GNUNET_MQ_hd_fixed_size (request,
- GNUNET_MESSAGE_TYPE_FS_CADET_QUERY,
- struct CadetQueryMessage,
- NULL),
- GNUNET_MQ_handler_end ()
- };
- struct GNUNET_HashCode port;
- if (GNUNET_YES !=
- GNUNET_CONFIGURATION_get_value_number (GSF_cfg,
- "fs",
- "MAX_CADET_CLIENTS",
- &sc_count_max))
- return;
- GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
- "Initializing cadet FS server with a limit of %llu connections\n",
- sc_count_max);
- cadet_map = GNUNET_CONTAINER_multipeermap_create (16, GNUNET_YES);
- cadet_handle = GNUNET_CADET_connect (GSF_cfg);
- GNUNET_assert (NULL != cadet_handle);
- GNUNET_CRYPTO_hash (GNUNET_APPLICATION_PORT_FS_BLOCK_TRANSFER,
- strlen (GNUNET_APPLICATION_PORT_FS_BLOCK_TRANSFER),
- &port);
- cadet_port = GNUNET_CADET_open_port (cadet_handle,
- &port,
- &connect_cb,
- NULL,
- &window_change_cb,
- &disconnect_cb,
- handlers);
- }
- /**
- * Shutdown subsystem for non-anonymous file-sharing.
- */
- void
- GSF_cadet_stop_server ()
- {
- GNUNET_CONTAINER_multipeermap_iterate (cadet_map,
- &GSF_cadet_release_clients,
- NULL);
- GNUNET_CONTAINER_multipeermap_destroy (cadet_map);
- cadet_map = NULL;
- if (NULL != cadet_port)
- {
- GNUNET_CADET_close_port (cadet_port);
- cadet_port = NULL;
- }
- if (NULL != cadet_handle)
- {
- GNUNET_CADET_disconnect (cadet_handle);
- cadet_handle = NULL;
- }
- GNUNET_assert (NULL == sc_head);
- GNUNET_assert (0 == sc_count);
- }
- /* end of gnunet-service-fs_cadet.c */
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